biochemistry midterms
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Questions and Answers

What is the role of a catalyst in a chemical reaction?

  • It speeds up the reaction without being consumed. (correct)
  • It lowers the reaction temperature required.
  • It is used up during the reaction.
  • It increases the activation energy needed.

    • What does a holoenzyme consist of?

  • An apoenzyme and a cofactor. (correct)
  • A metal ion and a coenzyme.
  • An enzyme and a substrate.
  • Only the apoenzyme.

    • Which type of enzymes require metal for their function?

  • Metalloenzymes. (correct)
  • Coenzymes.
  • Catalytic enzymes.
  • Allosteric enzymes.

    • What distinguishes low-density lipoproteins (LDLs) from high-density lipoproteins (HDLs)?

    <p>LDLs transport cholesterol from the liver to various body tissues.</p> Signup and view all the answers

    Which of the following statements about statins is true?

    <p>They are widely prescribed to lower cholesterol levels.</p> Signup and view all the answers

    Which bile salt contains glycine as its alipathic group?

    <p>Glycocholate</p> Signup and view all the answers

    Which type of fats are predominantly saturated?

    <p>Fats</p> Signup and view all the answers

    What is the primary characteristic of oils compared to fats?

    <p>Oils are predominantly unsaturated</p> Signup and view all the answers

    Which of the following is considered a 'good fat'?

    <p>Polyunsaturated fats</p> Signup and view all the answers

    What type of chemical reaction is hydrolysis of triacylglycerols?

    <p>Reverse of esterification</p> Signup and view all the answers

    Which of the following describes waxes?

    <p>They are water-repellent and hydrophobic</p> Signup and view all the answers

    What process is responsible for the solidification of fats from liquid oils?

    <p>Hydrogenation</p> Signup and view all the answers

    Which hormones are classified as Vitamin D Hormones?

    <p>Vit.D2</p> Signup and view all the answers

    Which of the following fats is categorized as a 'bad fat'?

    <p>Saturated fats</p> Signup and view all the answers

    What is the typical state of fats at room temperature?

    <p>Solid or semisolid</p> Signup and view all the answers

    What is the primary function of messenger RNA (mRNA)?

    <p>To carry information specifying the amino acid sequence of a protein to the ribosome</p> Signup and view all the answers

    Which statement about translation is accurate?

    <p>Only mRNA is translated to protein</p> Signup and view all the answers

    What is a codon?

    <p>A sequence of three mRNA nucleotides that codes for a specific amino acid</p> Signup and view all the answers

    What initiates the process of translation?

    <p>AUG codon</p> Signup and view all the answers

    During DNA replication, what occurs to the parent DNA molecule?

    <p>It unwinds and serves as a template for new strands</p> Signup and view all the answers

    What ensures the new DNA molecules are identical to the original set?

    <p>DNA proofreading mechanisms</p> Signup and view all the answers

    Which of the following codons is a stop codon?

    <p>UAA</p> Signup and view all the answers

    What is the result of a frameshift mutation?

    <p>It causes a protein to be synthesized with an altered sequence.</p> Signup and view all the answers

    Which type of mutation involves the addition or loss of DNA bases?

    <p>Frameshift mutation</p> Signup and view all the answers

    In what way does a deletion mutation affect the chromosome?

    <p>It removes or loses a chromosomal segment.</p> Signup and view all the answers

    What is the primary goal of the polymerase chain reaction (PCR)?

    <p>To create many copies of a specific DNA region.</p> Signup and view all the answers

    What occurs during the annealing step of the PCR process?

    <p>Primers bind to the original DNA strands.</p> Signup and view all the answers

    What type of lipids are known as energy-storage lipids?

    <p>Triacylglycerols</p> Signup and view all the answers

    What is the process of reversing a segment within a chromosome called?

    <p>Inversion</p> Signup and view all the answers

    Which kind of lipids are classified as membrane lipids?

    <p>Phospholipids</p> Signup and view all the answers

    What defines a translocation mutation?

    <p>It moves a segment from one chromosome to a nonhomologous chromosome.</p> Signup and view all the answers

    What is the primary function of simple glycerides?

    <p>Energy storage</p> Signup and view all the answers

    Which of the following statements about eicosanoids is true?

    <p>They are derived from arachidonic acid.</p> Signup and view all the answers

    What is the parent structure of sphingolipids?

    <p>Sphingosine</p> Signup and view all the answers

    How many fatty acids esterify with glycerol to form a triglyceride?

    <p>3</p> Signup and view all the answers

    What characterizes a mixed triacylglycerol?

    <p>It has different R groups or fatty acids attached.</p> Signup and view all the answers

    What is the energy yield of triglycerides compared to carbohydrates or proteins?

    <p>9 cal/g</p> Signup and view all the answers

    What effect do eicosanoids typically have in the body?

    <p>Mediating inflammation</p> Signup and view all the answers

    Which type of triglyceride has all the same fatty acids attached?

    <p>Simple Triacylglycerol</p> Signup and view all the answers

    What is a characteristic feature of eicosanoids?

    <p>Short lifespan</p> Signup and view all the answers

    Which statement about DHA is true?

    <p>It plays a role in neural and visual function development.</p> Signup and view all the answers

    What role does helicase play in DNA replication?

    <p>It unwinds the DNA helix and separates the strands.</p> Signup and view all the answers

    Which enzyme is responsible for adding RNA primers during DNA replication?

    <p>Primase</p> Signup and view all the answers

    Which process ensures the continuity of the lagging strand during DNA replication?

    <p>Synthesis of Okazaki fragments</p> Signup and view all the answers

    What does ligase do in the process of DNA replication?

    <p>Joins DNA segments on discontinuous strands</p> Signup and view all the answers

    How would you describe the relationship between adenine and thymine according to Chargaff's rule?

    <p>They are equivalent in quantity.</p> Signup and view all the answers

    Which of the following correctly describes transcription?

    <p>It copies DNA into RNA.</p> Signup and view all the answers

    What determines the property of an amino acid?

    <p>The side chain (R)</p> Signup and view all the answers

    Under what conditions do amino acids exist as zwitterions?

    <p>Normal cellular conditions with no net charge</p> Signup and view all the answers

    Which statement about the stereochemistry of amino acids is true?

    <p>Proteins are generally composed of L-amino acids</p> Signup and view all the answers

    How does the pH of a solution affect the structure of amino acids?

    <p>Increasing pH causes zwitterions to lose a proton</p> Signup and view all the answers

    What is the fundamental role of proteins in cellular functions?

    <p>They are involved in virtually all cell functions</p> Signup and view all the answers

    Which type of mutation involves the reversal of a segment within a chromosome?

    <p>Inversion</p> Signup and view all the answers

    During which step of PCR are primers attached to the original DNA strands?

    <p>Annealing</p> Signup and view all the answers

    Which mutation involves the loss of a chromosomal segment?

    <p>Deletion</p> Signup and view all the answers

    What characterizes energy-storage lipids?

    <p>They are primarily triacylglycerols.</p> Signup and view all the answers

    What is the outcome when a segment of DNA is duplicated?

    <p>It may attach to a sister chromatid.</p> Signup and view all the answers

    What is the main purpose of the polymerase chain reaction?

    <p>To produce specific DNA regions.</p> Signup and view all the answers

    Which type of mutation refers to the movement of a DNA segment to a nonhomologous chromosome?

    <p>Translocation</p> Signup and view all the answers

    Which lipids are classified as membrane lipids?

    <p>Phospholipids</p> Signup and view all the answers

    What is the primary function of antioxidants such as vitamin C and vitamin E in food preservation?

    <p>They prevent undesirable oxidation processes.</p> Signup and view all the answers

    What occurs during the hydrogenation of triacylglycerols?

    <p>Carbon–carbon single bonds are formed.</p> Signup and view all the answers

    What role do cofactors play in the activity of enzymes?

    <p>They enhance or assist the catalytic properties of enzymes.</p> Signup and view all the answers

    What is unique about enzymes in relation to their substrates?

    <p>Enzymes possess active sites for specific substrate interaction.</p> Signup and view all the answers

    What is an apoenzyme?

    <p>An inactive form of an enzyme without its cofactor.</p> Signup and view all the answers

    Which statement best describes saturated fatty acids in the context of hydrogenation?

    <p>They are produced by the reduction of unsaturated fatty acids.</p> Signup and view all the answers

    How do enzymes affect the activation energy of a reaction?

    <p>They lower the activation energy required for the reaction.</p> Signup and view all the answers

    What are the potential effects of rancidity in fats and oils?

    <p>Objectionable odors and loss of nutritional quality.</p> Signup and view all the answers

    What effect does hydrogenation have on unsaturated fatty acids?

    <p>It alters them into saturated fatty acids.</p> Signup and view all the answers

    Which type of fatty acid is typically formed during the hydrogenation process?

    <p>Saturated fatty acid.</p> Signup and view all the answers

    What is the primary mode of action of statins?

    <p>Inhibition of HMG-CoA reductase</p> Signup and view all the answers

    Which enzyme is responsible for the decarboxylation of pyruvate?

    <p>Pyruvate decarboxylase</p> Signup and view all the answers

    Which classification of enzymes catalyzes oxidation-reduction reactions?

    <p>Oxidoreductases</p> Signup and view all the answers

    What type of reaction do isomerases facilitate?

    <p>Transfer of functional groups within the same molecule</p> Signup and view all the answers

    Which enzyme is an example of an oxidoreductase that transfers H+?

    <p>Lactate dehydrogenase</p> Signup and view all the answers

    Which enzyme catalyzes the removal of a carboxyl group from pyruvate?

    <p>DOPA decarboxylase</p> Signup and view all the answers

    What role do reductases play in biochemical reactions?

    <p>They reduce substrates by transferring electrons</p> Signup and view all the answers

    What is a function of transferases in the body?

    <p>They transfer functional or chemical groups</p> Signup and view all the answers

    Which example best illustrates the function of an isomerase?

    <p>Conversion of D-alanine to L-alanine</p> Signup and view all the answers

    Which statement about the action of dehydrogenases is true?

    <p>They introduce double bonds by removing hydrogen atoms.</p> Signup and view all the answers

    What term describes the presence of a carboxyl group in fatty acids?

    <p>Hydrophilicity</p> Signup and view all the answers

    How does the degree of saturation affect melting point and boiling point of fatty acids?

    <p>Saturated fatty acids have higher melting points.</p> Signup and view all the answers

    At what chain length do fatty acids typically become soluble in water?

    <p>Up to 10 carbons</p> Signup and view all the answers

    What effect does the presence of a double bond have on the physical properties of fatty acids?

    <p>Lowers melting point</p> Signup and view all the answers

    Which type of fatty acid is generally more soluble in water?

    <p>Unsaturated fatty acid</p> Signup and view all the answers

    What structural characteristic do most fatty acids share?

    <p>An even number of carbons</p> Signup and view all the answers

    How does solubility change as the length of the fatty acid chain increases?

    <p>Solubility decreases with more carbons</p> Signup and view all the answers

    What is the primary function of lyases in biochemical reactions?

    <p>Cleave C-C, C-O, or C-N bonds without hydrolysis or oxidation</p> Signup and view all the answers

    Which model of enzyme-substrate binding considers three-dimensional flexibility?

    <p>Induced fit model</p> Signup and view all the answers

    What is a specific characteristic of competitive inhibitors?

    <p>Compete with the substrate for the active site</p> Signup and view all the answers

    Which type of lyase is responsible for the removal of water from a substrate?

    <p>Dehydratase</p> Signup and view all the answers

    What effect does a non-competitive inhibitor have on an enzyme's Km and Vmax?

    <p>Keeps Km unchanged and decreases Vmax</p> Signup and view all the answers

    What component is essential for the structural role of phospholipids in biological membranes?

    <p>Polar and nonpolar portions</p> Signup and view all the answers

    Which of the following is a characteristic of glycolipids?

    <p>Have a recognition site on cell surfaces</p> Signup and view all the answers

    Which lipid serves as a major component of the myelin sheath in nerve tissues?

    <p>Ceramide derivatives</p> Signup and view all the answers

    What is the parent structure of phosphoglycerides?

    <p>Phosphatidic acid</p> Signup and view all the answers

    What is a common function of membrane lipids?

    <p>Structural framework</p> Signup and view all the answers

    Which statement correctly describes the composition of phospholipids?

    <p>Contain a fatty acid, alcohol, and a phosphate group</p> Signup and view all the answers

    What are ceramides primarily composed of?

    <p>Fatty acids and sphingosine</p> Signup and view all the answers

    In cell membranes, what structural arrangement do phospholipids form?

    <p>Lipid bilayers</p> Signup and view all the answers

    What role do glycolipids play regarding blood types?

    <p>They anchor blood type carbohydrates in the RBC membrane</p> Signup and view all the answers

    What is a characteristic of fats compared to oils?

    <p>Predominantly saturated</p> Signup and view all the answers

    Which process breaks down triacylglycerols into mono- or diacylglycerol and fatty acids?

    <p>Hydrolysis</p> Signup and view all the answers

    How are waxes generally described in terms of their chemical properties?

    <p>Hydrophobic and water-repellent</p> Signup and view all the answers

    Which type of fat can be classified as both good and bad?

    <p>Polyunsaturated fats</p> Signup and view all the answers

    What is the state of oils typically at room temperature?

    <p>Liquids</p> Signup and view all the answers

    Which vitamin D hormone is primarily found in plant tissue?

    <p>Vitamin D2</p> Signup and view all the answers

    Which chemical reaction involves the addition of a fatty acid to a glycerol molecule?

    <p>Esterification</p> Signup and view all the answers

    Which fatty acid types are categorized as important 'good fats'?

    <p>Omega-3 and omega-6</p> Signup and view all the answers

    What is the source distinction for fats and oils?

    <p>Fats primarily come from animal sources, while oils come from plants</p> Signup and view all the answers

    What is the combination that forms a glucocerebroside?

    <p>Ceramide + glucose</p> Signup and view all the answers

    Which of the following compounds is a glycolipid?

    <p>Ganglioside</p> Signup and view all the answers

    What type of linkage connects NANA to the oligosaccharide in gangliosides?

    <p>Alpha linkage</p> Signup and view all the answers

    What is the primary role of sphingomyelin in the body?

    <p>Used primarily in nerve tissue</p> Signup and view all the answers

    Which statement about cholesterol is true?

    <p>It has a cyclopentanoperhydrophenanthrene structure.</p> Signup and view all the answers

    Which of the following acts as an emulsifier for fatty acids?

    <p>Bile acids</p> Signup and view all the answers

    What percentage of all lipids in humans are sphingolipids?

    <p>25%</p> Signup and view all the answers

    Which molecule is primarily associated with the myelin sheath?

    <p>Sphingomyelin</p> Signup and view all the answers

    What characteristic of phospholipids allows them to form cell membranes?

    <p>Hydrophilic heads and hydrophobic tails</p> Signup and view all the answers

    What is the key structural feature of bile acids?

    <p>Derived from cholesterol</p> Signup and view all the answers

    What is the primary reason that longer hydrocarbon chains in fatty acids reduce solubility in water?

    <p>They are primarily made of hydrophobic components.</p> Signup and view all the answers

    Which type of fatty acid is solid at room temperature?

    <p>Saturated fatty acids</p> Signup and view all the answers

    What effect do double bonds have on the solubility of fatty acids?

    <p>They shorten the hydrocarbon chain.</p> Signup and view all the answers

    Which group in fatty acids is responsible for their hydrophilic nature?

    <p>Carboxyl group</p> Signup and view all the answers

    What is a characteristic of low-density lipoproteins (LDLs)?

    <p>They are linked to higher heart disease risk.</p> Signup and view all the answers

    How does the chain length affect the solubility of short-chain fatty acids in water?

    <p>Shorter chains are highly soluble.</p> Signup and view all the answers

    What property do unsaturated fatty acids generally have due to their structural configuration?

    <p>They are liquid at room temperature.</p> Signup and view all the answers

    What happens to zwitterions when the pH of the solution is increased?

    <p>They lose a proton</p> Signup and view all the answers

    Which type of amino acids are primarily utilized in protein assembly?

    <p>L-amino acids</p> Signup and view all the answers

    What effect does high salt concentration have on enzymes?

    <p>It can denature the enzyme</p> Signup and view all the answers

    What do animals require as essential fatty acids in their diets?

    <p>N-6 and N-3 fatty acids</p> Signup and view all the answers

    Which animals lack the ability to carry out chain elongation and desaturation?

    <p>Carnivores like cats and some fish</p> Signup and view all the answers

    What structure is a derivative of a 20-carbon fatty acid, which contains a cyclopentane ring and oxygen-containing functional groups?

    <p>Prostaglandins</p> Signup and view all the answers

    What is a characteristic feature of cis fatty acids compared to trans fatty acids?

    <p>Kinked structure affecting their physical properties</p> Signup and view all the answers

    How do essential fatty acids (EFA) generally affect body functions?

    <p>Promote smooth muscle relaxation and contraction</p> Signup and view all the answers

    Which of the following statements best describes butyric acid?

    <p>Present in coconut oil</p> Signup and view all the answers

    What role do prostaglandins play in the body?

    <p>They increase pain sensation and inflammation</p> Signup and view all the answers

    What significant effect does aspirin have related to prostaglandins?

    <p>Inhibits their synthesis</p> Signup and view all the answers

    What is true about the relationship between carbon chain length and the melting point of fatty acids?

    <p>Double bonds lower melting points regardless of chain length</p> Signup and view all the answers

    What is a characteristic of saturated fats?

    <p>They are typically solid or semisolid at room temperature.</p> Signup and view all the answers

    What is one of the processes involved in the chemical reactions of triacylglycerols?

    <p>Saponification</p> Signup and view all the answers

    What is a property of waxes?

    <p>They are hydrophobic and do not dissolve in water.</p> Signup and view all the answers

    Which type of fatty acids are omega-3 and omega-6 classified as?

    <p>Good fats</p> Signup and view all the answers

    Which reaction is the reverse of the esterification reaction involving triacylglycerols?

    <p>Hydrolysis</p> Signup and view all the answers

    What distinguishes fats from oils regarding their physical state?

    <p>Fats are predominantly saturated; oils are predominantly unsaturated.</p> Signup and view all the answers

    Which of the following processes relates to breaking ester bonds in triacylglycerols?

    <p>Saponification</p> Signup and view all the answers

    What is the principal function of simple glycerides?

    <p>Energy storage</p> Signup and view all the answers

    What characterizes eicosanoids in terms of their physiological effects?

    <p>They exert effects at very low concentrations.</p> Signup and view all the answers

    How many fatty acids can esterify with one glycerol molecule to form a triglyceride?

    <p>Three fatty acids</p> Signup and view all the answers

    What type of triacylglycerol has different fatty acids attached to the glycerol?

    <p>Mixed Triacylglycerol</p> Signup and view all the answers

    Which of the following statements about DHA is accurate?

    <p>DHA is required for proper neural and visual function development.</p> Signup and view all the answers

    What is the primary characteristic of triacylglycerols in terms of their composition?

    <p>They are composed of fatty acids and glycerol.</p> Signup and view all the answers

    What role do eicosanoids have in inflammation?

    <p>They mediate inflammatory responses.</p> Signup and view all the answers

    What distinguishes a simple triacylglycerol from a mixed triacylglycerol?

    <p>Simple contains a single type of fatty acid.</p> Signup and view all the answers

    Which bile salt has taurine as its alipathic group?

    <p>Taurocholate</p> Signup and view all the answers

    What characterizes waxes?

    <p>They have a protective coating property.</p> Signup and view all the answers

    What type of fats are primarily derived from plant sources?

    <p>Polyunsaturated fats</p> Signup and view all the answers

    During the hydrolysis of triacylglycerols, what is produced?

    <p>Mono- or diacylglycerol and fatty acids</p> Signup and view all the answers

    What role do codons play in the process of translation?

    <p>They signal the start or end of protein synthesis</p> Signup and view all the answers

    During DNA replication, what happens to the base sequences?

    <p>They must be identical to the original set</p> Signup and view all the answers

    Which of the following describes a codon?

    <p>A sequence of three RNA nucleotides coding for an amino acid</p> Signup and view all the answers

    Which statement about DNA replication is true?

    <p>It results in two identical daughter DNA molecules</p> Signup and view all the answers

    What is the function of tRNA during translation?

    <p>To carry amino acids to the ribosome</p> Signup and view all the answers

    What is the significance of the AUG codon?

    <p>It is a start codon that codes for methionine</p> Signup and view all the answers

    What are the hydrophilic components of fatty acids?

    <p>Carboxyl group</p> Signup and view all the answers

    How does the length of the hydrocarbon chain affect solubility in water?

    <p>Longer chains decrease solubility</p> Signup and view all the answers

    What is the state of saturated fatty acids at room temperature?

    <p>Solid</p> Signup and view all the answers

    What effect does an increasing number of double bonds in fatty acids have?

    <p>Increases water solubility</p> Signup and view all the answers

    What characteristic differentiates short chain fatty acids in terms of solubility?

    <p>Slightly soluble in water</p> Signup and view all the answers

    What type of cholesterol is associated with saturated fatty acids?

    <p>Low-density lipoprotein (LDL)</p> Signup and view all the answers

    Which of the following statements about unsaturated fatty acids is true?

    <p>They contain multiple double bonds</p> Signup and view all the answers

    Why are long-chain fatty acids less soluble in water?

    <p>They have fewer double bonds</p> Signup and view all the answers

    Which factor primarily affects fatty acids' solubility in water?

    <p>Hydrocarbon chain length</p> Signup and view all the answers

    What is the main reason for eating before taking aspirin?

    <p>To neutralize stomach acids</p> Signup and view all the answers

    What is the role of thromboxanes in the body?

    <p>To promote platelet aggregation</p> Signup and view all the answers

    Why are trans fatty acids considered harmful?

    <p>They facilitate blood clotting</p> Signup and view all the answers

    What are leukotrienes derived from?

    <p>Arachidonic acid</p> Signup and view all the answers

    What effect does LTC4 and LTD4 have on the body?

    <p>Increase bronchoconstriction</p> Signup and view all the answers

    Which of the following distinguishes prostaglandins from thromboxanes?

    <p>Prostaglandins have conjugated double bonds</p> Signup and view all the answers

    What is the characteristic structure of prostanoic acid?

    <p>A cyclic ether ring with oxygen-containing groups</p> Signup and view all the answers

    What potential risk does aspirin pose to patients with dengue fever?

    <p>It causes gastrointestinal bleeding</p> Signup and view all the answers

    Which fatty acid is a precursor for eicosanoids?

    <p>Arachidonic acid</p> Signup and view all the answers

    What does IL-1, IL-2, and IFN-γ promote in the immune response?

    <p>T-cell proliferation</p> Signup and view all the answers

    What is the main structural role of phospholipids in biological membranes?

    <p>They form the lipid bilayer that composes cell membranes</p> Signup and view all the answers

    What are glycolipids primarily composed of?

    <p>A fatty acid, sphingosine, and a carbohydrate</p> Signup and view all the answers

    Which component is a part of the basic structure of phospholipids?

    <p>Phosphatidic acid</p> Signup and view all the answers

    What function do some lipids serve on the surface of a cell?

    <p>Recognition sites for cellular interaction</p> Signup and view all the answers

    What distinguishes sphingomyelin from other types of lipids?

    <p>It is formed from ceramide and phosphorylcholine</p> Signup and view all the answers

    What is the primary role of ceramide derivatives in the human body?

    <p>Insulatory function in nerve tissues</p> Signup and view all the answers

    How are lipids characterized to ensure they can form membranes?

    <p>They must contain both polar and nonpolar portions</p> Signup and view all the answers

    What is a major component of the cellular membranes formed by phospholipids?

    <p>Lipid bilayers</p> Signup and view all the answers

    What role does the carbohydrate play in glycolipids?

    <p>Facilitates cellular recognition and interaction</p> Signup and view all the answers

    What type of lipids primarily constitute the myelin sheath surrounding neurons?

    <p>Sphingomyelin</p> Signup and view all the answers

    What is the primary structural feature of an alpha helix?

    <p>Spiral shape stabilized by hydrogen bonds</p> Signup and view all the answers

    Which type of proteins are generally water-soluble and compact in shape?

    <p>Enzymes and hormones</p> Signup and view all the answers

    What is the primary function of chaperones in protein folding?

    <p>They assist proteins to fold correctly</p> Signup and view all the answers

    Where is deoxyribonucleic acid (DNA) primarily found?

    <p>Within the cell nucleus</p> Signup and view all the answers

    What distinguishes peptides from proteins in terms of amino acid count?

    <p>Peptides contain less than 50 amino acids</p> Signup and view all the answers

    What structural characteristic distinguishes ribose from deoxyribose sugar?

    <p>Ribose has an OH group on the second carbon</p> Signup and view all the answers

    Which structure is formed by the interactions of multiple polypeptide chains?

    <p>Quaternary structure</p> Signup and view all the answers

    Which nitrogenous base pair forms two hydrogen bonds?

    <p>Adenine and Thymine</p> Signup and view all the answers

    How many hydrogen bonds connect Cytosine and Guanine in DNA?

    <p>Three</p> Signup and view all the answers

    What is the primary function of RNA within the cell?

    <p>To synthesize proteins</p> Signup and view all the answers

    What type of bonding connects the two strands of DNA?

    <p>Hydrogen Bonding</p> Signup and view all the answers

    Which statement accurately describes the composition of a nucleotide?

    <p>Nitrogen base, sugar, and phosphate</p> Signup and view all the answers

    What makes fatty acids amphipathic?

    <p>They contain both hydrophilic and hydrophobic groups.</p> Signup and view all the answers

    What effect does increasing the number of double bonds in fatty acids have on solubility?

    <p>It increases solubility in water.</p> Signup and view all the answers

    Which statement about saturated fatty acids is true?

    <p>They are associated with bad cholesterol.</p> Signup and view all the answers

    What describes the solubility characteristics of short-chain fatty acids?

    <p>They are sparingly soluble in water.</p> Signup and view all the answers

    How does the length of the hydrocarbon chain affect the solubility of fatty acids?

    <p>Longer chains decrease water solubility.</p> Signup and view all the answers

    Which fatty acid characteristic is linked with being solid at room temperature?

    <p>High level of saturation.</p> Signup and view all the answers

    Why are longer hydrocarbon chains associated with lower solubility in water?

    <p>They have fewer functional groups.</p> Signup and view all the answers

    What contributes to the solid nature of saturated fatty acids at room temperature?

    <p>The absence of double bonds.</p> Signup and view all the answers

    Which property is characteristic of unsaturated fatty acids compared to saturated fatty acids?

    <p>They tend to be more soluble in water.</p> Signup and view all the answers

    What type of bonds do lyases cleave?

    <p>C-C, C-O, or C-N bonds</p> Signup and view all the answers

    What is the primary characteristic of the lock and key model of enzyme activity?

    <p>Enzyme is rigid and does not change</p> Signup and view all the answers

    Which enzyme is an example of a dehydratase?

    <p>Carbonic anhydrase</p> Signup and view all the answers

    How does a competitive inhibitor affect enzyme activity?

    <p>Competes with substrate for the active site</p> Signup and view all the answers

    What is the effect of non-competitive inhibitors on enzyme activity?

    <p>Change the Vmax without affecting Km</p> Signup and view all the answers

    What distinguishes the induced fit model from the lock and key model?

    <p>Enzyme shape is altered after substrate binding</p> Signup and view all the answers

    Which of the following reactions is catalyzed by a deaminase?

    <p>Removal of NH3 from a substrate</p> Signup and view all the answers

    What is the role of hydratases in biochemical reactions?

    <p>Addition of H2O to a substrate</p> Signup and view all the answers

    Which inhibitor acts by binding to a site other than the active site?

    <p>Non-competitive inhibitor</p> Signup and view all the answers

    What type of enzyme is a decarboxylase responsible for?

    <p>Removal of CO2 from a substrate</p> Signup and view all the answers

    Which type of molecule binds to enzymes and reduces their activity?

    <p>Inhibitors</p> Signup and view all the answers

    What happens to a zwitterion when the pH of the solution is lowered?

    <p>It gains a proton</p> Signup and view all the answers

    Which amino acid stereochemistry is predominantly found in proteins?

    <p>L-amino acids</p> Signup and view all the answers

    What can high salt concentration do to an enzyme?

    <p>Denature it</p> Signup and view all the answers

    How many amino acids are known to occur in nature?

    <p>700</p> Signup and view all the answers

    What is the significance of the isoelectric point for amino acids?

    <p>It is the point where amino acids have no net charge.</p> Signup and view all the answers

    What is the primary linkage between amino acids in proteins?

    <p>Peptide bond</p> Signup and view all the answers

    What does changing the pH of a solution containing amino acids affect?

    <p>The charge of the zwitterions</p> Signup and view all the answers

    What is the primary function of ribosomal RNA (rRNA)?

    <p>To form the functional ribosome</p> Signup and view all the answers

    What occurs during transcription in protein synthesis?

    <p>DNA is copied into RNA</p> Signup and view all the answers

    Which type of RNA is responsible for bringing amino acids to the ribosome?

    <p>Transfer RNA (tRNA)</p> Signup and view all the answers

    In which process are genetic messages decoded to build proteins?

    <p>Translation</p> Signup and view all the answers

    What is the most abundant type of RNA found in cells?

    <p>Ribosomal RNA (rRNA)</p> Signup and view all the answers

    What does the Central Dogma of molecular biology describe?

    <p>The flow of genetic information in cells</p> Signup and view all the answers

    Which of the following best describes what occurs during replication?

    <p>Identical copies of DNA are made</p> Signup and view all the answers

    Which of the following correctly defines a metalloenzyme?

    <p>An enzyme that requires metal ions in its structure.</p> Signup and view all the answers

    What role do coenzymes play in enzymatic reactions?

    <p>They are organic molecules that facilitate enzyme activity.</p> Signup and view all the answers

    How do low-density lipoproteins (LDLs) function in the body?

    <p>They carry excess cholesterol from the liver to other parts of the body.</p> Signup and view all the answers

    Which characteristic describes a catalyst in chemical reactions?

    <p>It speeds up the reaction without being used up in the process.</p> Signup and view all the answers

    What is the primary role of statins in the body?

    <p>To lower cholesterol levels in the bloodstream.</p> Signup and view all the answers

    What is the basic structure found in all phosphoglycerides?

    <p>Phosphatidic acid</p> Signup and view all the answers

    Which function do glycolipids primarily serve in the cell membrane?

    <p>Recognition sites</p> Signup and view all the answers

    What type of lipid is used primarily in nerve tissues as myelin sheath?

    <p>Sphingomyelin</p> Signup and view all the answers

    Which of the following characteristics must lipids have to be suitable for forming bilayers?

    <p>Nonpolar tail and polar head</p> Signup and view all the answers

    What component is combined with sphingosine to produce ceramide?

    <p>Fatty acid</p> Signup and view all the answers

    Which characteristic defines fatty acids as amphipathic?

    <p>Presence of both hydrophilic and hydrophobic groups</p> Signup and view all the answers

    Which of the following describes the composition of phospholipids?

    <p>Fatty acid, alcohol, and phosphatidic acid</p> Signup and view all the answers

    Which lipid type contributes significantly to the structure of membranes?

    <p>Phospholipids</p> Signup and view all the answers

    What kind of lipid is sphingomyelin classified as?

    <p>Sphingophospholipid</p> Signup and view all the answers

    What primarily influences the solubility of fatty acids in water?

    <p>The length of the hydrocarbon chain</p> Signup and view all the answers

    Why are short-chain fatty acids considered sparingly soluble in water?

    <p>They have polar carboxylic acid groups</p> Signup and view all the answers

    What is the primary function of lipids in a biological membrane?

    <p>Structural integrity and insulation</p> Signup and view all the answers

    What type of fatty acids are generally solid at room temperature?

    <p>Saturated fatty acids</p> Signup and view all the answers

    Which component anchors blood type carbohydrates into red blood cell membranes?

    <p>Glycolipids</p> Signup and view all the answers

    Which fatty acids carry bad cholesterol in the body?

    <p>Saturated fatty acids</p> Signup and view all the answers

    How does the structure of unsaturated fatty acids differ from saturated fatty acids?

    <p>Unsaturated fatty acids contain fewer hydrogen atoms</p> Signup and view all the answers

    What is the solubility trend for fatty acids with increased hydrocarbon chain length?

    <p>Solubility in water decreases</p> Signup and view all the answers

    What is a consequence of having fewer double bonds in fatty acids?

    <p>Higher melting point</p> Signup and view all the answers

    What is the component that, when added to ceramide, forms glucocerebroside?

    <p>Glucose</p> Signup and view all the answers

    Which type of linkage connects oligosaccharides to ceramide in gangliosides?

    <p>Beta linkages</p> Signup and view all the answers

    Which molecule primarily forms the myelin sheath in nerve tissue?

    <p>Sphingomyelin</p> Signup and view all the answers

    What type of sugar forms a sulfatide when combined with ceramide?

    <p>Sulfated sugar</p> Signup and view all the answers

    Which structural feature is NOT associated with cholesterol?

    <p>Presence of nitrogen</p> Signup and view all the answers

    Which hormone class originates from cholesterol in the adrenal cortex?

    <p>Steroid hormones</p> Signup and view all the answers

    What role do bile acids play in the body?

    <p>Emulsify fatty acids</p> Signup and view all the answers

    Which part of the phospholipid is hydrophilic?

    <p>Ionic head groups</p> Signup and view all the answers

    What is the loss of the double bond in ring B of cholesterol characteristic of?

    <p>Conversion to bile acids</p> Signup and view all the answers

    What is a significant property of sphingolipids within human cells?

    <p>They are a major component of nerve tissue</p> Signup and view all the answers

    What is a frameshift mutation?

    <p>The addition or loss of DNA bases that alters a gene's reading frame</p> Signup and view all the answers

    Which of the following describes the process of translocation in genetics?

    <p>A segment from one chromosome is moved to a nonhomologous chromosome</p> Signup and view all the answers

    What occurs during the denaturation step of PCR?

    <p>The DNA strands are separated into single strands</p> Signup and view all the answers

    What is the purpose of annealing in the PCR process?

    <p>To allow primers to bind to the template DNA</p> Signup and view all the answers

    Which type of mutation involves the loss of a chromosomal segment?

    <p>Deletion</p> Signup and view all the answers

    Which of the following lipids is classified as an energy-storage lipid?

    <p>Triacylglycerols</p> Signup and view all the answers

    What characterizes an inversion mutation?

    <p>A segment within a chromosome is reversed</p> Signup and view all the answers

    Which bile salt is characterized by having taurine as its alipathic group?

    <p>Taurocholate</p> Signup and view all the answers

    Which type of fat is typically found in plant sources and is liquid at room temperature?

    <p>Unsaturated fats</p> Signup and view all the answers

    What chemical reaction describes the breaking of ester bonds in triacylglycerols?

    <p>Hydrolysis</p> Signup and view all the answers

    What is the primary feature of waxes in terms of their interaction with water?

    <p>Hydrophobic</p> Signup and view all the answers

    Which process involves the reverse action of esterification when dealing with triacylglycerols?

    <p>Hydrolysis</p> Signup and view all the answers

    Which type of fat includes omega 3 and 6 fatty acids and is considered beneficial?

    <p>Polyunsaturated fats</p> Signup and view all the answers

    Which statement accurately describes the state of oils at room temperature?

    <p>Liquid</p> Signup and view all the answers

    Which of the following is a common source of triglycerides?

    <p>Animal products</p> Signup and view all the answers

    What type of fats tend to be categorized as 'bad fats'?

    <p>Trans fats</p> Signup and view all the answers

    What type of bond is broken during the hydrolysis of triacylglycerols?

    <p>Ester bonds</p> Signup and view all the answers

    What property of waxes makes them suitable as insulators?

    <p>Low thermal conductivity</p> Signup and view all the answers

    Which of the following is a typical state of waxes at room temperature?

    <p>Solid</p> Signup and view all the answers

    Which enzyme family is primarily responsible for catalyzing oxidation reactions in biological systems?

    <p>Oxidoreductases</p> Signup and view all the answers

    What is a common application of lanolin, a type of wax?

    <p>Protective baby skin treatment</p> Signup and view all the answers

    What is a primary characteristic of waxes in terms of chemical stability?

    <p>Relatively chemically stable</p> Signup and view all the answers

    What type of chemical reaction results in the production of aldhehydes or carboxylic acids from alkenes?

    <p>Oxidation</p> Signup and view all the answers

    What do saponification reactions produce when triacylglycerols undergo hydrolysis in a basic solution?

    <p>Glycerol and salt of fatty acid</p> Signup and view all the answers

    What defines the role of enzymes as catalysts in biological systems?

    <p>They are not consumed during the reactions</p> Signup and view all the answers

    Which of the following waxes is secreted by the sebaceous glands of the skin?

    <p>Sebum</p> Signup and view all the answers

    What is the metabolic state of an enzyme when it is combined with a cofactor?

    <p>Holoenzyme</p> Signup and view all the answers

    What property of waxes allows them to function as lubricants?

    <p>Lubricating properties</p> Signup and view all the answers

    Which type of molecules can act as coenzymes in enzyme reactions?

    <p>Organic molecules derived from vitamins</p> Signup and view all the answers

    What is the primary role of low-density lipoproteins (LDLs) in the body?

    <p>Transport cholesterol from the liver to tissues</p> Signup and view all the answers

    What is a common function of statins?

    <p>Inhibit cholesterol production in the liver</p> Signup and view all the answers

    Which of the following best describes a catalyst in a chemical reaction?

    <p>A chemical that lowers the activation energy</p> Signup and view all the answers

    What is a characteristic of butyric acid?

    <p>It is predominant in coconut oil.</p> Signup and view all the answers

    Which essential fatty acids do animals require in their diets?

    <p>n-6 and n-3 fatty acids</p> Signup and view all the answers

    Which animals are unable to perform chain elongation and desaturation of fatty acids?

    <p>Cats and some fish</p> Signup and view all the answers

    What may prostaglandins contribute to in the body?

    <p>Increasing inflammation responses</p> Signup and view all the answers

    What distinguishes cis fatty acids from trans fatty acids?

    <p>Trans fatty acids have double bonds in a specific configuration.</p> Signup and view all the answers

    What is one effect of essential fatty acids in the animal diet?

    <p>They are necessary for prostaglandin production.</p> Signup and view all the answers

    How do the boiling and melting points of fatty acids generally change with chain length?

    <p>Longer chains have higher boiling and melting points.</p> Signup and view all the answers

    What role does aspirin play in the body during fever?

    <p>It inhibits the enzyme needed to make prostaglandins.</p> Signup and view all the answers

    Which statement accurately describes the effect of double bonds on fatty acids?

    <p>More double bonds lower the melting point.</p> Signup and view all the answers

    What type of mutation results from the addition or loss of DNA bases, altering a gene's reading frame?

    <p>Frameshift mutation</p> Signup and view all the answers

    Which process occurs first during the polymerase chain reaction (PCR)?

    <p>Denaturation of the template</p> Signup and view all the answers

    What is a characteristic of a deletion mutation?

    <p>It removes a chromosomal segment.</p> Signup and view all the answers

    What characterizes emulsification lipids?

    <p>They assist in the digestion of fats.</p> Signup and view all the answers

    Which statement correctly describes an inversion mutation?

    <p>It reverses a segment within a chromosome.</p> Signup and view all the answers

    What does not contribute to the classification of lipids based on solubility?

    <p>Functionality of the lipid</p> Signup and view all the answers

    What is the primary outcome of a frameshift mutation?

    <p>The resulting protein is often nonfunctional.</p> Signup and view all the answers

    What is a characteristic of saturated fatty acids compared to unsaturated fatty acids?

    <p>Higher melting point</p> Signup and view all the answers

    What factor primarily affects the solubility of fatty acids in water?

    <p>Length of the hydrocarbon chain</p> Signup and view all the answers

    Why are fatty acids with double bonds more soluble in water than their saturated counterparts?

    <p>Double bonds create bends in the chain</p> Signup and view all the answers

    What generally occurs to the melting point of a fatty acid as the number of carbon atoms increases?

    <p>It increases</p> Signup and view all the answers

    For fatty acids with fewer than 10 carbon atoms, what is true regarding their solubility?

    <p>They are highly soluble in water</p> Signup and view all the answers

    What determines the degree of saturation in fatty acids?

    <p>The presence of double bonds</p> Signup and view all the answers

    Which statement correctly describes the hydrophilic nature of fatty acids?

    <p>The carboxyl group is hydrophilic</p> Signup and view all the answers

    What is the solubility trend of fatty acids as the chain length increases beyond 10 carbon atoms?

    <p>Decreases and can become insoluble</p> Signup and view all the answers

    What distinguishes straight-chain fatty acids from branched-chain fatty acids in terms of melting point?

    <p>Straight chains have higher melting points due to closer packing</p> Signup and view all the answers

    What defines a metalloenzyme?

    <p>Enzymes that use metal ions as a cofactor</p> Signup and view all the answers

    What is the role of coenzymes in enzymatic reactions?

    <p>To assist in the activation of substrate molecules</p> Signup and view all the answers

    Which statement about cholesterol transport is accurate?

    <p>High levels of HDLs are associated with lower heart disease risk.</p> Signup and view all the answers

    What distinguishes a holoenzyme from an apoenzyme?

    <p>An apoenzyme includes its cofactor.</p> Signup and view all the answers

    What is the primary function of a catalyst in a chemical reaction?

    <p>To lower the activation energy needed for the reaction</p> Signup and view all the answers

    What effect does increasing the chain length of fatty acids have on the melting temperature?

    <p>Increases melting temperature</p> Signup and view all the answers

    Which type of fatty acid contains only one double bond?

    <p>Monounsaturated fatty acid</p> Signup and view all the answers

    What is the impact of unsaturation on the melting temperature of fatty acids?

    <p>Decreases melting temperature</p> Signup and view all the answers

    Which of the following fatty acids is classified as saturated?

    <p>Stearic acid (18:0)</p> Signup and view all the answers

    What is the primary reason that saturated fatty acids have higher melting temperatures than unsaturated fatty acids?

    <p>More Van der Waals forces</p> Signup and view all the answers

    How is a polyunsaturated fatty acid characterized?

    <p>Two or more double bonds</p> Signup and view all the answers

    Which chain length category includes fatty acids with 6 to 12 carbon atoms?

    <p>Medium chain</p> Signup and view all the answers

    What characteristic of fatty acid molecules is affected by their degree of saturation?

    <p>Melting temperature</p> Signup and view all the answers

    Which of the following fatty acids is expected to have the lowest melting point?

    <p>Arachidonic acid (20:4)</p> Signup and view all the answers

    How do Van der Waals forces contribute to the properties of fatty acids?

    <p>They increase melting temperature.</p> Signup and view all the answers

    What is the primary reason that short chain fatty acids are sparingly soluble in water?

    <p>They have a polar carboxylic acid group.</p> Signup and view all the answers

    How does the length of the hydrocarbon chain affect the solubility of fatty acids in water?

    <p>Longer chains decrease solubility.</p> Signup and view all the answers

    What effect do an increasing number of double bonds have on the solubility of fatty acids?

    <p>They increase the solubility.</p> Signup and view all the answers

    Which group is responsible for the amphipathic nature of fatty acids?

    <p>Hydrophilic carboxyl group.</p> Signup and view all the answers

    Which of the following statements is true regarding the solubility of fatty acids?

    <p>Unsaturated fatty acids are generally more soluble than saturated.</p> Signup and view all the answers

    What type of cholesterol is primarily associated with saturated fatty acids?

    <p>Low-density lipoprotein (LDL).</p> Signup and view all the answers

    What characterizes the state of fatty acids with longer hydrocarbon chains?

    <p>They tend to be solid at room temperature.</p> Signup and view all the answers

    What property do fatty acids exhibit due to their amphipathic nature?

    <p>They can form micelles in aqueous solutions.</p> Signup and view all the answers

    What primarily determines the difference in solubility between saturated and unsaturated fatty acids?

    <p>The number of double bonds present.</p> Signup and view all the answers

    What characteristic is true for butyric acid?

    <p>It is present in coconut oil.</p> Signup and view all the answers

    Which statement about cis and trans fatty acids is accurate?

    <p>Cis fatty acids generally have lower melting points than trans fatty acids.</p> Signup and view all the answers

    What function do prostaglandins serve in the body?

    <p>They control body temperature.</p> Signup and view all the answers

    Which animals cannot carry out chain elongation and desaturation of fatty acids?

    <p>Cats and some fish</p> Signup and view all the answers

    What distinguishes deoxyribose from ribose in nucleic acids?

    <p>Deoxyribose is characterized by the absence of an oxygen atom at C2.</p> Signup and view all the answers

    Which statement accurately describes the pairing of nitrogenous bases in DNA?

    <p>Cytosine pairs with Guanine through three hydrogen bonds.</p> Signup and view all the answers

    Which of the following best describes the structural characteristics of DNA?

    <p>DNA consists of two anti-parallel polynucleotide strands.</p> Signup and view all the answers

    Which of the following correctly describes a difference between purines and pyrimidines?

    <p>Purines are characterized by a double ring structure.</p> Signup and view all the answers

    What role does RNA primarily serve in the cell?

    <p>RNA's primary function is the synthesis of proteins.</p> Signup and view all the answers

    What occurs during the formation of a nucleoside?

    <p>A nitrogenous base is linked to a sugar without a phosphate.</p> Signup and view all the answers

    Which of the following statements regarding DNA strand direction is true?

    <p>One strand runs 5' to 3', while the other runs 3' to 5'.</p> Signup and view all the answers

    What is the function of helicase during DNA replication?

    <p>It unwinds the helix and separates the strands.</p> Signup and view all the answers

    Which enzyme is responsible for synthesizing RNA primers during DNA replication?

    <p>Primase</p> Signup and view all the answers

    What does DNA ligase do in the DNA replication process?

    <p>It joins DNA segments on the lagging strand.</p> Signup and view all the answers

    According to Chargaff's rule, what is the relationship between adenine and thymine in DNA?

    <p>The content of adenine equals the content of thymine.</p> Signup and view all the answers

    What is the primary role of DNA polymerase III during replication?

    <p>It copies each strand of DNA.</p> Signup and view all the answers

    What process occurs when RNA is synthesized from a DNA template?

    <p>Transcription</p> Signup and view all the answers

    What occurs during the replacement of RNA primers in DNA replication?

    <p>DNA polymerase I replaces primers with DNA nucleotides.</p> Signup and view all the answers

    What does the enzyme helicase specifically break during DNA replication?

    <p>Hydrogen bonds between DNA strands.</p> Signup and view all the answers

    What are Okazaki fragments formed from during DNA replication?

    <p>Discontinuous synthesis on the lagging strand.</p> Signup and view all the answers

    What is the most stable form of DNA found under physiological conditions?

    <p>B form</p> Signup and view all the answers

    What type of mutation does not affect the activity of the protein?

    <p>Silence mutation</p> Signup and view all the answers

    Which form of DNA is characterized by a left-handed helix and a zigzag appearance?

    <p>Z form</p> Signup and view all the answers

    What change occurs during a missense mutation?

    <p>One amino acid is substituted for another.</p> Signup and view all the answers

    Which type of mutation could result in an incomplete protein due to a premature stop signal?

    <p>Nonsense mutation</p> Signup and view all the answers

    Which characteristic distinguishes the A form of DNA?

    <p>Right-handed double helix with wider turns</p> Signup and view all the answers

    What term describes a change in the DNA sequence that may lead to neutral effects on cell function?

    <p>Polymorphism</p> Signup and view all the answers

    Which of the following is NOT a type of point mutation?

    <p>Duplication mutation</p> Signup and view all the answers

    Which feature of lipids distinguishes them from other biomolecules?

    <p>Soluble in non-polar organic solvents</p> Signup and view all the answers

    What type of mutation involves a change of single base pairs that creates a stop codon?

    <p>Nonsense mutation</p> Signup and view all the answers

    How does the length of a fatty acid chain affect its melting temperature?

    <p>Longer chain length increases melting temperature</p> Signup and view all the answers

    What type of fatty acid is characterized by one double bond?

    <p>Monounsaturated fatty acid</p> Signup and view all the answers

    Which fatty acid has a higher melting temperature?

    <p>Stearic acid (18:0)</p> Signup and view all the answers

    What effect does unsaturation have on the melting point of fatty acids?

    <p>Decreases the melting point by inducing disorder</p> Signup and view all the answers

    Which of the following is considered a classification of fatty acids based on chain length?

    <p>Short, medium, and long chain</p> Signup and view all the answers

    What role does saturation play in the physical properties of fatty acids?

    <p>It promotes ordered formation and increases melting temperature</p> Signup and view all the answers

    What is the typical characteristic of a polyunsaturated fatty acid?

    <p>Contains two or more double bonds</p> Signup and view all the answers

    What fatty acid is an example of a medium chain fatty acid?

    <p>Lauric acid (12)</p> Signup and view all the answers

    Which statement best describes the relationship between chain length and Van der Waals forces in fatty acids?

    <p>Long chain fatty acids have more Van der Waals forces</p> Signup and view all the answers

    What is a primary characteristic of short chain fatty acids?

    <p>They are less than 6 carbon atoms in length</p> Signup and view all the answers

    What is the primary function of HMG-CoA reductase in biochemical reactions?

    <p>Inhibit cholesterol synthesis</p> Signup and view all the answers

    Which enzyme is responsible for the conversion of lactate to pyruvate?

    <p>Lactate dehydrogenase</p> Signup and view all the answers

    What type of reaction do oxidoreductases primarily facilitate?

    <p>Oxidation and reduction reactions</p> Signup and view all the answers

    Which of the following enzymes catalyzes the removal of COO from pyruvate?

    <p>Pyruvate decarboxylase</p> Signup and view all the answers

    Which of the following statements is true about transferases?

    <p>They are involved in transferring functional or chemical groups.</p> Signup and view all the answers

    What is the function of messenger RNA (mRNA) in the cell?

    <p>It carries information specifying the amino acid sequence to the ribosome.</p> Signup and view all the answers

    Which statement accurately describes the role of codons?

    <p>They code for specific amino acids and dictate the order of amino acids in a protein.</p> Signup and view all the answers

    What occurs during the process of DNA replication?

    <p>A single DNA molecule unwinds and daughter strands are synthesized.</p> Signup and view all the answers

    Which codons signify the end of a gene?

    <p>UAA, UAG, and UGA</p> Signup and view all the answers

    At what stage does DNA replication occur within the cell cycle?

    <p>During interphase</p> Signup and view all the answers

    What role do rRNA and tRNA play in translation?

    <p>They help assemble amino acids into proteins.</p> Signup and view all the answers

    What is the significance of proofreading mechanisms during DNA replication?

    <p>To ensure accurate base pairing and correct most replication errors.</p> Signup and view all the answers

    What distinguishes essential fatty acids (EFA) in animals?

    <p>Animals require n-6 and n-3 fatty acids in their diets.</p> Signup and view all the answers

    Which type of fatty acids can animals not synthesize at the methyl end?

    <p>Essential fatty acids.</p> Signup and view all the answers

    What is the main function of prostaglandins in the body?

    <p>To mediate processes such as pain and inflammation.</p> Signup and view all the answers

    What is a characteristic difference between cis and trans fatty acids?

    <p>Cis fatty acids are more commonly found in nature.</p> Signup and view all the answers

    Why do cats need long-chain fatty acids in their diet?

    <p>They cannot carry out chain elongation and desaturation.</p> Signup and view all the answers

    How do animals utilize essential fatty acids from their diet?

    <p>By incorporating them directly into cell membranes.</p> Signup and view all the answers

    What happens when an animal consumes aspirin during a fever?

    <p>It inhibits enzyme activity related to prostaglandin production.</p> Signup and view all the answers

    What is a common characteristic of fatty acids with shorter carbon chains?

    <p>They are more water-soluble than longer chains.</p> Signup and view all the answers

    Which statement accurately describes the role of n-6 and n-3 fatty acids in animals?

    <p>They must be obtained through the diet.</p> Signup and view all the answers

    What is the primary role of eicosanoids in the body?

    <p>Mediating physiological responses</p> Signup and view all the answers

    What type of triglyceride contains different fatty acids attached to glycerol?

    <p>Mixed Triacylglycerol</p> Signup and view all the answers

    Which of the following accurately describes the function of triacylglycerol?

    <p>Energy storage</p> Signup and view all the answers

    What is the typical energy yield of triglycerides compared to carbohydrates?

    <p>9 cal/g</p> Signup and view all the answers

    What is a notable characteristic of eicosanoids in terms of their concentrations?

    <p>Act at extremely low concentrations</p> Signup and view all the answers

    What is the primary component of simple glycerides?

    <p>Fatty acids and glycerol</p> Signup and view all the answers

    Which fatty acid composition is typical for a diglyceride?

    <p>Two fatty acids</p> Signup and view all the answers

    What allows triglycerides to be compact and lighter than other forms of energy storage?

    <p>Absence of water</p> Signup and view all the answers

    What type of molecule serves as the parent structure for sphingolipids?

    <p>Sphingosine</p> Signup and view all the answers

    What describes the relationship between DHA and neural development?

    <p>DHA is necessary for proper neural function</p> Signup and view all the answers

    What is one of the main uses of waxes due to their low thermal conductivity?

    <p>As insulators to slow down heat transfer</p> Signup and view all the answers

    Which of the following is NOT a characteristic of waxes?

    <p>They are chemically unstable.</p> Signup and view all the answers

    What process occurs during the oxidation of triacylglycerols?

    <p>Production of aldehydes or carboxylic acids</p> Signup and view all the answers

    What is a common application of lanolin?

    <p>Protective treatment for baby skin</p> Signup and view all the answers

    What is the role of enzymes in biochemical reactions?

    <p>They accelerate chemical reactions without being consumed.</p> Signup and view all the answers

    Which wax is specifically the secretion from honey bees?

    <p>Beeswax</p> Signup and view all the answers

    What is a notable characteristic of cerumen?

    <p>It is also called earwax.</p> Signup and view all the answers

    What type of molecules can result from the oxidation of alkenes?

    <p>Aldehydes and/or carboxylic acids</p> Signup and view all the answers

    Which of the following waxes is frequently used for treating sore nipples in breastfeeding mothers?

    <p>Lanolin</p> Signup and view all the answers

    What happens to a catalyst after it has facilitated a reaction?

    <p>It is regenerated and can be reused.</p> Signup and view all the answers

    What is the most abundant type of RNA in protein synthesis?

    <p>Ribosomal RNA (rRNA)</p> Signup and view all the answers

    Which statement accurately describes the role of transfer RNA (tRNA)?

    <p>tRNA carries amino acids to the ribosome.</p> Signup and view all the answers

    Which part of protein synthesis involves reading genetic messages to create proteins?

    <p>Translation</p> Signup and view all the answers

    What is the role of transcription in the central dogma of molecular biology?

    <p>It copies DNA into RNA.</p> Signup and view all the answers

    Which of the following is NOT a step in protein synthesis?

    <p>Replication</p> Signup and view all the answers

    What is the main chemical property of waxes that allows them to be used as insulators?

    <p>Low thermal conductivity</p> Signup and view all the answers

    Which type of RNA is primarily responsible for carrying genetic codes from the nucleus to the ribosomes?

    <p>Messenger RNA (mRNA)</p> Signup and view all the answers

    Which substance is classified as a wax secretion from honey bees?

    <p>Bees wax</p> Signup and view all the answers

    What occurs as a result of the oxidation of triacylglycerols?

    <p>Breakage of double bonds</p> Signup and view all the answers

    Which of the following is a use of lanolin?

    <p>Protective baby skin treatment</p> Signup and view all the answers

    What is a characteristic of enzymes in biological systems?

    <p>They accelerate chemical reactions</p> Signup and view all the answers

    What contributes to the hydrophilic nature of a fatty acid molecule?

    <p>The terminal carboxyl group</p> Signup and view all the answers

    How does the degree of saturation affect the melting point of fatty acids?

    <p>Unsaturated fatty acids have lower melting points than saturated ones.</p> Signup and view all the answers

    Which of the following statements about solubility is correct?

    <p>Fatty acids with fewer than 10 carbon atoms are soluble in water.</p> Signup and view all the answers

    What is a common characteristic of most fatty acids?

    <p>They have an even number of carbon atoms.</p> Signup and view all the answers

    How do unsaturated fatty acids compare in solubility to saturated fatty acids?

    <p>Unsaturated fatty acids are more soluble.</p> Signup and view all the answers

    Which factor generally determines the melting temperature of fatty acids?

    <p>The presence of double bonds</p> Signup and view all the answers

    What is the relationship between carbon atom count and water solubility in fatty acids?

    <p>Greater than 10 carbon atoms lead to decreased solubility.</p> Signup and view all the answers

    Which characteristic makes unsaturated fatty acids more soluble than their saturated equivalents?

    <p>The presence of double bonds</p> Signup and view all the answers

    What happens to the melting point of fatty acids when they contain double bonds?

    <p>It decreases.</p> Signup and view all the answers

    What contributes to the lower solubility of long chain saturated fatty acids in water?

    <p>Hydrophobic hydrocarbon chains</p> Signup and view all the answers

    What type of fatty acids are more soluble in water?

    <p>Short chain fatty acids</p> Signup and view all the answers

    How does the presence of double bonds affect fatty acid solubility?

    <p>Shortens the hydrocarbon chain</p> Signup and view all the answers

    What characteristic do fatty acids contain that contribute to their amphipathic nature?

    <p>Both hydrophilic and hydrophobic groups</p> Signup and view all the answers

    Which fatty acids are categorized as bad cholesterol?

    <p>Saturated fatty acids</p> Signup and view all the answers

    How does chain length affect the melting temperature of fatty acids?

    <p>Longer chain lengths increase the melting temperature.</p> Signup and view all the answers

    What phase are saturated fatty acids typically in at room temperature?

    <p>Solid</p> Signup and view all the answers

    What is true about unsaturated fatty acids regarding their melting temperature?

    <p>Unsaturated fatty acids have lower melting temperatures due to disorder.</p> Signup and view all the answers

    Which of the following statements about the solubility of fatty acids is true?

    <p>Higher concentration of double bonds increases solubility</p> Signup and view all the answers

    Which factor contributes to the ordered formation and increased melting temperature of fatty acids?

    <p>Saturation allowing for more intermolecular attraction.</p> Signup and view all the answers

    What ultimately defines whether a fatty acid is soluble in water?

    <p>The length of the hydrocarbon chain and double bond presence</p> Signup and view all the answers

    Which of the following fatty acids is an example of a polyunsaturated acid?

    <p>Arachidonic acid (20:4)</p> Signup and view all the answers

    Which group in fatty acids contributes to their hydrophilicity?

    <p>Carboxyl group</p> Signup and view all the answers

    What characteristic defines monounsaturated fatty acids?

    <p>They have one double bond in their structure.</p> Signup and view all the answers

    What is a common characteristic of fatty acids with multiple double bonds?

    <p>Lower melting points</p> Signup and view all the answers

    How are fatty acids classified based on their chain length?

    <p>According to the number of carbon atoms in their chains.</p> Signup and view all the answers

    What is the melting temperature of stearic acid (18:0)?

    <p>69.9 °C</p> Signup and view all the answers

    What effect does increased saturation have on fatty acids?

    <p>Promotes more Van der Waals forces, increasing melting temperature.</p> Signup and view all the answers

    How does the degree of unsaturation relate to the physical state of fatty acids at room temperature?

    <p>Unsaturated fatty acids tend to be liquid at room temperature.</p> Signup and view all the answers

    What distinguishes high-density lipoproteins (HDLs) from low-density lipoproteins (LDLs)?

    <p>HDLs transport excess cholesterol from tissues to the liver, while LDLs carry cholesterol from the liver.</p> Signup and view all the answers

    What is a characteristic feature of a catalyst in a chemical reaction?

    <p>It remains unchanged after the reaction occurs.</p> Signup and view all the answers

    What defines the metabolic activity of a holoenzyme?

    <p>It contains a cofactor in addition to the apoenzyme.</p> Signup and view all the answers

    What happens to the melting temperature as the chain length of a fatty acid increases?

    <p>It increases due to more Van der Waals bonds.</p> Signup and view all the answers

    Which type of fatty acid has one double bond and is typically liquid at room temperature?

    <p>Monounsaturated fatty acid</p> Signup and view all the answers

    How does the degree of saturation affect the intermolecular attraction in fatty acids?

    <p>More saturation increases ordered formation and attraction.</p> Signup and view all the answers

    Which fatty acid is classified as polyunsaturated?

    <p>Arachidonic acid (C20:4)</p> Signup and view all the answers

    What is a characteristic of short-chain fatty acids?

    <p>They typically have fewer than 6 carbon atoms.</p> Signup and view all the answers

    What is the primary component of a cerebroside?

    <p>Ceramide and sugar</p> Signup and view all the answers

    How does unsaturation impact the melting point of fatty acids?

    <p>It decreases the melting point due to disorder.</p> Signup and view all the answers

    What sugar component leads to the formation of a galactocerebroside?

    <p>Galactose</p> Signup and view all the answers

    What type of fatty acid has the highest melting temperature among the example options?

    <p>Stearic acid (C18:0)</p> Signup and view all the answers

    Which of the following lipids is primarily used in nerve tissue?

    <p>Sphingomyelin</p> Signup and view all the answers

    What is a significant feature of cholesterol's structure?

    <p>Four fused rings</p> Signup and view all the answers

    Which function is primarily associated with bile acids derived from cholesterol?

    <p>Fat emulsification</p> Signup and view all the answers

    Which of the following components does NOT contribute to a sphingolipid's structure?

    <p>Phosphoric acid</p> Signup and view all the answers

    What is a common role of cholesterol in the body?

    <p>Steroid synthesis</p> Signup and view all the answers

    The polar sites of a phospholipid are described as being what?

    <p>Hydrophilic</p> Signup and view all the answers

    What role do both hydrocarbon and polar parts of phospholipids play?

    <p>Forming cell walls</p> Signup and view all the answers

    What is the primary function of triacylglycerols?

    <p>Energy storage</p> Signup and view all the answers

    How many fatty acids are typically esterified to form a diglyceride?

    <p>Two</p> Signup and view all the answers

    What distinguishes a mixed triacylglycerol from a simple triacylglycerol?

    <p>It has different fatty acids attached to glycerol</p> Signup and view all the answers

    Which lipid is characterized as having a parent structure of sphingosine?

    <p>Sphingolipids</p> Signup and view all the answers

    What essential fatty acid is noted for its role in neural and visual function development?

    <p>Docosahexaenoic acid (DHA)</p> Signup and view all the answers

    What is a key characteristic of eicosanoids regarding their lifespan?

    <p>They typically have a very short lifespan</p> Signup and view all the answers

    Which component is essential for the formation of ceramide?

    <p>Fatty acid</p> Signup and view all the answers

    How are sphingomyelin and ceramide related?

    <p>Sphingomyelin is ceramide plus phosphorylcholine.</p> Signup and view all the answers

    Which of the following accurately describes the composition of glycolipids?

    <p>A fatty acid, sphingosine, and a carbohydrate</p> Signup and view all the answers

    What is a common function of lipids in the plasma membrane of neurons?

    <p>Insulating nerve signals</p> Signup and view all the answers

    What constitutes the basic structure of all phosphoglycerides?

    <p>Phosphatidic acid</p> Signup and view all the answers

    What type of lipids are primarily found in the myelin sheath of nerve tissues?

    <p>Sphingomyelin</p> Signup and view all the answers

    Which property is necessary for lipids to function well in forming membranes?

    <p>Possessing a polar and nonpolar portion</p> Signup and view all the answers

    What characteristic helps glycosphingolipids function as recognition sites on the cell surface?

    <p>Their hydrophilic nature</p> Signup and view all the answers

    Study Notes

    DNA vs RNA

    • DNA is found in the cell nucleus
    • DNA stores and transfers genetic information
    • DNA is passed from existing cells to new cells during cell division
    • RNA occurs in all parts of a cell
    • RNA's primary function is protein synthesis

    Purines vs Pyrimidines

    • Five nitrogenous bases exist
    • Purines are double ring structures (Guanine, Adenine)
    • Pyrimidines are single ring structures (Cytosine, Thymine, Uracil)
    • Guanine and Adenine are found in both DNA and RNA
    • Cytosine is found in both DNA and RNA
    • Thymine is found in DNA
    • Uracil is found in RNA

    Nucleoside Formation

    • Nitrogenous base is connected to C1 of the sugar
    • C2 of the sugar is differentiated by H or OH
    • C5 is where the phosphate is attached

    Structural Characteristics of DNA

    • DNA consists of two anti-parallel polynucleotides
    • One strand runs 5' to 3', the other runs 3' to 5'
    • Sugar-phosphate backbone is on the outside
    • Hydrophobic bases are on the inside

    Base Pairing

    • A pyrimidine pairs with a purine
    • A pairs with T (two hydrogen bonds)
    • G pairs with C (three hydrogen bonds)

    DNA Replication

    • Helicase unwinds the DNA helix
    • Primase adds RNA primers
    • Polymerase III copies the DNA strands
    • Polymerase I replaces RNA primers with DNA nucleotides
    • Ligase seals the DNA segments

    Transcription

    • Process of copying DNA segment to RNA
    • DNA segments that produce messenger RNA (mRNA) encode proteins

    Types of RNA

    • Ribosomal RNA (rRNA)
    • Most abundant
    • Structural component of ribosomes
    • Transfer RNA (tRNA)
    • Second most abundant
    • Carries amino acids to ribosomes
    • Messenger RNA (mRNA)
    • Carries information to ribosomes, specifying amino acid sequence
    • Only type of RNA that is translated

    Translation

    • mRNA is translated into protein
    • Codon: a sequence of three mRNA nucleotides that codes for an amino acid
    • The order of codons determines the order of amino acids
    • Start codon: AUG (methionine)
    • Stop codons: UAA, UAG, UGA

    Central Dogma

    • Replication: DNA makes identical copies of DNA
    • Transcription: DNA makes RNA
    • Translation: RNA makes proteins

    Mutations

    • Changes in the DNA sequence at a particular gene locus
    • Can be harmful, beneficial, or neutral

    Point Mutations

    • Silent mutation: no change in protein activity
    • Missense mutation: one amino acid substituted
    • Nonsense mutation: premature stop codon, shortened protein
    • Frameshift mutation: addition or deletion of DNA bases, altered reading frame

    Polymerase Chain Reaction (PCR)

    • Technique to make many copies of a specific DNA region
    • Steps: denaturation, annealing, extension

    Lipids

    • Insoluble or sparingly soluble in water
    • Soluble in nonpolar organic solvents
    • Types of lipids include triacylglycerols, phospholipids, sphingolipids, waxes, steroids, and terpenes
    • Classified by solubility

    Fatty Acids

    • Members of carboxylic acids
    • Hydrocarbon chain with a terminal carboxyl group (COOH)
    • Saturated fatty acids: solid at room temperature
    • Unsaturated fatty acids: liquid at room temperature

    Prostaglandins

    • c20 fatty-acid derivatives
    • Involved in raising body temperature, inhibiting gastric juices, increasing mucus secretion.

    Thormboxanes

    • c20 fatty-acid derivatives
    • Promote platelet aggregation (blood clotting)

    Leukotrienes

    • c20 fatty-acid derivatives
    • Promote inflammation

    Higher Unsaturated Fatty Acids (UFAs)

    • HUFA: Polyunsaturated fatty acids with greater than 20 carbon atoms
    • Essential for proper neural and visual function

    Essential Fatty Acids (EFAs)

    • Cannot be synthesized by animals.
    • Must be obtained from diet
    • EFA n-6 and n-3

    Cholesterol

    • Major steroid in the body
    • Precursor to bile salts, steroid hormones

    Protein Denaturation

    • Loss of a protein's natural shape and function
    • Factors that cause denaturation:
    • Heat
    • Alcohol
    • Acids
    • Inorganic chemicals
    • Organic chemicals
    • Alkalis

    Chemical Reactions of Triacylglycerols

    • Hydrolysis: breakdown with water (lipases)
    • Saponification: breakdown with base (produces soap)

    Protein Structural Organization

    • Primary structure: linear sequence of amino acids
    • Secondary structure: local folding patterns (alpha helix, beta sheet)
    • Tertiary structure: overall 3D shape
    • Quaternary structure: interactions between multiple polypeptide chains

    Peptide Bonds

    • Bonds that link amino acids in a polypeptide chain
    • Formed by condensation reaction (loss of water)

    Enzymes

    • Protein catalysts that accelerate chemical reactions
    • Types:
      • Oxidoreductases
      • Transferases
      • Hydrolases
      • Lyases
      • Isomerases
      • Ligases

    Enzyme Activity Factors

    • Temperature
    • pH
    • Substrate Concentration
    • Enzyme Concentration
    • Inhibitors/Activators

    Isoelectric Point (pI)

    • pH at which an amino acid has no net charge (zwitterion)

    Stereochemistry of Amino Acids

    • Chiral amino acids (except glycine) exist as L or D isomers
    • Proteins generally utilize L-amino acids

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