Chemistry of Life (2023) Presentation PDF

Chemistry of Life 2023-03-08 www.njctl.org https://njctl.org/video/?v=Cik1kaWKUTw  Table of Contents: Chemistry of Life Click on a topic to go to that section ∙Org...

Chemistry of Life 2023-03-08 www.njctl.org https://njctl.org/video/?v=Cik1kaWKUTw  Table of Contents: Chemistry of Life Click on a topic to go to that section ∙Organic Compounds ∙Dehydration Synthesis, Hydrolysis ∙ Carbohydrates, Polysaccharides ∙ Nucleic Acids ∙ Amino Acids, Proteins ∙ Lipids Move any photo or image in this presentation to reveal a link to its source, providing attribution and additional information.  Organic Compounds Return to Table of https://njctl.org/video/?v=x_q3VWDoZvY Contents  Carbon Carbon is the backbone of biological molecules. Organic chemistry is the chemistry of carbon compounds. Carbon has the ability to form long chains, enabling the creation of large molecules: proteins, lipids, carbohydrates, and nucleic acids.  Organic Compounds Organic molecules consist of carbon atoms covalently bonded to each other and other atoms, most commonly: ∙Hydrogen ∙Oxygen ∙Nitrogen and frequently: ∙Phosphorous ∙Sulfur and, occasionally, other trace elements such as the halogens.  Organic Chemistry Carbon atoms can form diverse molecules by bonding to four other atoms, which are in different directions. This allows the molecule to take on a 3D configuration. It is this 3D structure that defines the molecule's function.  Electron Configuration Carbon has four valence electrons with which to make covalent bonds. Valence electrons are the electrons in the outer "shell." The inner electrons can't form bonds. A covalent bond forms between two atoms. Each atom shares at least one of its outer electrons with the other when the bond is formed. The result is a pair of electrons being shared (one from each atom) to form a single covalent bond.  Electron Configuration If a carbon atom is bonded to four other atoms, it H will share one of its electrons with each of the four other atoms, making four bonds. H C H In this diagram of methane, the central carbon H atom has formed four single covalent bonds, one with each hydrogen. The carbon atom has shared one of its electrons with each hydrogen while each hydrogen shares its electron with the carbon. The result is a pair of electrons forming each bond. Single bonds are shown by straight lines.  Electron Configuration If carbon bonds with fewer than four other atoms, it can share more than one of its electrons with one or more of the other atoms. If it shares two electrons, it forms a double bond. O C O If it shares three electrons, it forms a triple bond. O C Both types of bonds are illustrated here with carbon dioxide and carbon monoxide. Carbon doesn't form quadruple bonds.  Electron Configuration When bonded with 4 atoms, carbon can H only have single bonds with each atom. Double and triple bonds can only occur H C H when fewer than four other atoms are bonded to carbon. H Double bonds are stronger and shorter than single bonds and triple bonds are O C O even stronger and shorter. On diagrams, single bonds are O C represented by one line, double bonds by two lines, and triple bonds by three.  Hydrocarbons These molecules consist of only carbon and hydrogen atoms. Each carbon atom makes 4 bonds. Each hydrogen atom makes 1 bond. Carbon-hydrogen bonds are non-polar. The non-polar bonds have a major impact on hydrocarbon behavior. Fossil fuels are examples of hydrocarbons that are formed from decaying organic matter.  Hydrocarbons Water is polar, so it will attract other polar molecules. Since hydrocarbons are not polar, they will not be attracted to water, and will not mix or dissolve in water. Oil (hydrocarbon) and water don't mix. Because hydrocarbons are not attracted to water, they are classified as hydrophobic.  Saturated Hydrocarbons In saturated hydrocarbons: ∙every carbon atom is bonded to four different atoms ∙no new atoms can be added along the chain  Unsaturated Hydrocarbons In unsaturated hydrocarbons: H H H ∙some of the carbon-carbon bonds H C C C C are double or triple bonds H H H H ∙those can be broken and replaced with a single bond double bond ∙at that point, additional atom(s) can be added ∙the carbon-carbon double bonds create 'kinks' on the hydrocarbon chain  1 Organic chemistry is a science based on the study of _____. A functional groups B carbon compounds Answer C water and its interaction with other kinds of B molecules D inorganic compounds E I need help. https://njctl.org/video/?v=ByfHq6wKnJ8 2 Which property of the carbon atom gives it the ability to make multiple types of covalent bonds and form long chains? A Carbon has 6 to 8 neutrons. Answer B Carbon has 4 valence electrons C Carbon forms strong ionic bonds B D All the above E I need help. https://njctl.org/video/?v=wpgBgFonFjg 3 Most of the time, Carbon forms what type(s) of bond(s)? A ionic Answer B hydrogen C C covalent D metallic E I need help https://njctl.org/video/?v=07VP5XZ-6bk  4 How many electron pairs does carbon share to complete its valence shell? A 2 B 4 C it depends Answer D 3 E I need help B https://njctl.org/video/?v=_ynoRFlm77k  5 Which of the following is an organic compound? A H2O B NaCl C C6H12O6 D O2 Answer E I need help C https://njctl.org/video/?v=4qlObhwBBO4  6 Hydrocarbons _____. A are polar Answer B are held together by ionic bonds C contain nitrogen D D contain only hydrogen and carbon atoms E I need help https://njctl.org/video/?v=hgItVxGejFo  7 What is the reason why hydrocarbons are not soluble in water? Answer A The majority of their bonds are polar covalent carbon to hydrogen linkages B B The majority of their bonds are nonpolar covalent carbon to hydrogen linkages C They are hydrophilic D They are lighter than water E I need help https://njctl.org/video/?v=yGED3cqWrDA  8 Hydrocarbons containing only single bonds between the carbon atoms are called __________. A saturated Answer B polar A C non-polar D unsaturated E I need help https://njctl.org/video/?v=IwAd_lh9hjI  9 Hydrocarbons containing double or triple bonds between some of the carbon atoms are called __________. A saturated B polar Answer C non-polar D unsaturated D E I need help https://njctl.org/video/?v=d9RC9mNCf48  10 Gasoline and water do not mix because gasoline is __________. A less dense than water B non-polar and water is polar C volatile and water is not Answer D polar and water is non-polar B E I need help https://njctl.org/video/?v=rvDQcLS70XU  Dehydration Synthesis, Hydrolysis Return to Table of https://njctl.org/video/?v=RCVoXZ0XOD8 Contents  Biological Macromolecules Hydrocarbons form the framework from which the 4 different classes of macromolecules (large molecules) have been derived. They are: ∙Proteins ∙Carbohydrates ∙Nucleic Acids ∙Lipids  Polymers Three of the classes of life’s organic molecules are polymers: carbohydrates, nucleic acids, and proteins. Although organisms share the same limited number of monomer types, each organism is unique based on the arrangement of how their monomers are used to make polymers. An immense variety of polymers can be built from a small set of monomers. Polymer: Monomer they're made from: Proteins Amino acids Simple sugars Carbohydrates (monosaccharides) Nucleic acids Nucleotides  Dehydration Synthesis Dehydration Synthesis Polymers are formed through a process called dehydration synthesis. Two monomers combine, a water molecule is removed, and a new molecule - a polymer - is created. This process is illustrated on the next slide. dehydration - removing a water molecule synthesis - combining of separate parts to make a new whole.  Dehydration Synthesis OH H + OH H molecule 1 molecule 2 removal of water molecule (dehydration) H2O OH H plus H2O new molecule is formed (synthesis)  Hydrolysis New molecules can also be formed by breaking existing molecules apart, allowing the products to react with other molecules. The breaking apart process is called Hydrolysis. A water molecule is added to a molecule that causes both molecules to split apart. The H and OH groups from the water will then combine with each product, as illustrated on the next slide. hydro (water) lysis (splitting)  Hydrolysis water molecule H2O original molecule OH H molecule 1 molecule 2 OH H + OH H Adding a water molecule (hydro) splits the original molecule into 2 new molecules (-lysis).  Dehydration Synthesis & Hydrolysis Dehydration Synthesis Monomer + Monomer Polymer + Water Reactants Products Hydrolysis Polymer + Water Monomer + Monomer Reactants Products  11 ____________ are to carbohydrates as ___________ are to proteins. A nucleic acids; amino acids B monosaccharides; amino acids Answer C amino acids; nucleic acids B D monosaccharides; nucleic acids E I need help https://njctl.org/video/?v=w4aJlG_Qqu8  12 The following equation is an example of: A dehydration synthesis B hydrolysis Answer C combustion D precipitation B E I need help C5H12 + H2O C3H7OH + C2H6 https://njctl.org/video/?v=hC3tJIwJ6Dk  13 The following equation is an example of: A dehydration synthesis B hydrolysis Answer C combustion D precipitation A E I need help C5H12 + C3H7OH C8H18 + H2O https://njctl.org/video/?v=G0_ldjz_m3g 14 Dehydration synthesis reactions join monomers to form polymers. Which of the following illustrates a dehydration synthesis reaction? Answer A C6H12O6 + C6H12O6 --> C12H22O11 + H2O B C3H6O3 + C3H6O3 --> C6H12O6 A C C6H12O6 + H2O --> C3H6O3 + C3H6O3 D C3H6O3 + H2O --> C3H6O4 E I need help https://njctl.org/video/?v=vqAEbcrsSQA  15 Which is true about dehydration synthesis? A one monomer loses a hydrogen atom, the other loses a hydroxyl group Answer B water is formed when monomers join D C covalent bonds are formed between monomers D all of the above are true E I need help https://njctl.org/video/?v=wBGLFhQFEKw  16 The results of dehydration synthesis can be reversed by: A condensation B hydrolysis C polymerization Answer D adding an amino group B E I need help https://njctl.org/video/?v=nAfAQMuT0dI  17 The products of dehydration synthesis are: A two monomers B a polymer and water C two polymers Answer D a hydroxyl group and a H atom B E I need help https://njctl.org/video/?v=xehAkRIpp40 18 The products of hydrolysis are: A larger than the original polymer B a polymer and water C two monomers Answer D a hydroxyl group and a H atom C E I need help https://njctl.org/video/?v=U-xDw0QW0vw  Carbohydrates, Polysaccharides Return to Table of https://njctl.org/video/?v=umkP2m5Zlqo Contents  Carbohydrates Carbohydrates are compounds consisting of carbon and water, hence the name carbo (carbon) hydrate (water). Since water is made of hydrogen and oxygen, the atoms that comprise carbohydrates are carbon, hydrogen and oxygen. Simple carbohydrates are also called sugars, monosaccharides or disaccharides.  Formula for Monosaccharides Monosaccharides have equal amounts of carbon and water. One way to write the general formula for them is: Cx(H2O)x That also means that they have twice as many hydrogen atoms as they have oxygen or carbon atoms, so the general formula can also be written as: CxH2xOx So, some possible formulas for monosaccharides are: C6H12O6 C7H14O7C3H6O3  Carbohydrates Monosaccharides are the simplest carbohydrates. They are the monomers that are used to build more complex carbohydrates. The most common of these are glucose and fructose. Disaccharides are formed by combining two monosaccharides. Table sugar (sucrose) is made up of glucose and fructose. Polysaccharides are formed by combining chains of many monosaccharides. https://njctl.org/video/?v=WpKpmKUp7Ps  Monosaccharides Monosaccharides are the simplest sugars. Their names typically end in "-ose." Examples include glucose and fructose. The basic roles of simple sugars are as: ∙fuel to do work ∙the raw materials for carbon backbones ∙the monomers from which larger carbohydrates are synthesized. Fruits and some vegetables are natural sources of fructose and glucose.  Carbohydrate Solubility Sugars all have many polar hydroxyl (OH-) groups in their structure. That makes them soluble in water. https://saylordotorg.github.io/text_the-basics-of-general-org anic-and-biological-chemistry/s19-02-classes-of-monosacch arides.html These drawings show the single and double bonds of two monosaccharides, but do not show their three-dimensional forms. There are other ways to represent the molecules.  Drawing Organic Molecules Organic molecules are difficult to visualize on paper because they are three dimensional and complex. There are several ways to draw them. We'll just show three methods, with brief explanations. ∙Straight line ∙Skeletal (line - angle) ∙Haworth Projections  Straight Line The simplest diagram shows all the atoms and bonds in the molecule and does not describe the 3D configuration. Single bonds are represented by 1 line, double bonds by 2 lines and triple bonds by 3 lines. Contrast the diagram of this glucose molecule with the one on https://chemistry.stackexchange.com/questions/57927/why-is-it-i the next slide. mportant-that-glucose-s-third-oh-group-points-to-the-left/57980  Skeletal Diagram of Glucose (line - angle) ∙A carbon atom is assumed to be at each vertex of the central figure. ∙Single bonds are single lines, double bonds are double lines, and triple bonds are triple lines. ∙When there are less than four bonds at a vertex, there are assumed to be enough H atoms to form 4 bonds with the C there. ∙Wedge lines show a bond coming out of the page. ∙Dashed lines show a bond going into the page. ∙Wavy lines indicate atoms present that are omitted from the diagram.  Haworth Projection of Glucose ∙The numbers represent the carbon atoms. You will see the numbers again when DNA is discussed (3' and 5'). ∙H atoms are not indicated, but are https://upload.wikimedia.org/wikipedia/commons/4/46/Hawo understood to be attached to the C atoms rth_projection_of_%CE%B1-D-_and_%CE%B1-L-Glucopyr anose.svg when there are not 4 bonds shown. ∙The thicker lines provide perspective by showing that the atoms are closer to the viewer.  Carbohydrate Structures In solution, sugars form cyclic structures that can connect to form chains of sugars. Fructose Glucose Sucrose  Disaccharides Cells link 2 simple sugars together to form disaccharides. Disaccharide formation is another example of a dehydration synthesis reaction. The most common disaccharide is sucrose (fructose + glucose). Sucrose  19 For a carbohydrate described by the formula: A 0 C5HxO5 B 5 x=? C 10 Answer D 1 C E I need help https://njctl.org/video/?v=DXNO7FZ1eeE  20 In the carbohydrate described by the formula CxH14Ox A 28 B 7 x=? C 2 Answer D 1 E I need help B https://njctl.org/video/?v=A_4pVIwDu8w  21 In the carbohydrate described by the formula CxH6Ox A 0 B 3 x=? Answer C 6 B D 12 E I need help https://njctl.org/video/?v=WCik5XrFUMk  22 Which of the following is an example of a monosaccharide? A sucrose B glucose Answer C fructose D B&C D E I need help https://njctl.org/video/?v=UPZ5FKweu2Y  23 Disaccharides are formed by combining how many monosaccharides? A 2 B 3 Answer C 4 D 5 A E I need help https://njctl.org/video/?v=BOmsOBSDFpU 24 What is another name for simple carbohydrates? A sugars B disaccharides Answer C monosaccharides D all of the above D E I need help https://njctl.org/video/?v=YPBVqssI1qI 25 What does the highlighted wedge line indicate about the bond? A It is an ionic bond. Answer B The bond points out of the page. C The bond points into the page. B D The bond is in the plane of the page. E I need help wedge https://njctl.org/video/?v=vKAvsQvyHlQ 26 What does the highlighted dashed line indicate about the bond? A It is an ionic bond. B The bond points out of the page. Answer C The bond points into the page. C D The bond is in the plane of the page. E I need help dashed line https://njctl.org/video/?v=4B7vZ8cEbrY 27 Which of the following are connected by a double bond in this diagram of the glucose molecule? A O and H Answer B C and OH D C C and H D C and O E I need help https://njctl.org/video/?v=WafXfWJxHeY  Polysaccharides Polysaccharides are polymers of glucose. Different monosaccharides are linked together, using dehydration synthesis reactions, to form several different polysaccharides. The three most important polysaccharides are: ∙starch ∙glycogen ∙cellulose. https://njctl.org/video/?v=uNJtCiNUWH0  Polysaccharides: Starch Unbranched Starch Starch is used ∙Different for longlink organisms term monosaccharides together to form energy severalstorage differentinpolysaccharides. plants. ∙The most important 3 are starch, glycogen, and cellulose. A∙Starch starch is can be for used unbranched long term energy storage in plants. or branched. ∙Can be branched (amylopectin) or unbranched (amylose). Branched Starch  Polysaccharides: Glycogen Glycogen has the same kind of bond between monomers as starch but it is always highly branched. ·Different organisms link monosaccharides together to form several different polysaccharides. It is used for long-term energy storage in animals, and in muscles to ·The most important 3 are starch, glycogen, and cellulose. provide a local supply of energy when needed. ·Starch is used for long term energy storage in plants. ·Can be branched (amylopectin) or unbranched (amylose). Glycogen can be broken down by a hydrolysis reaction to obtain glucose when organisms need energy.  Polysaccharides: Cellulose Cellulose is a carbohydrate used to make cell walls in plants. bonds. Cellulose has a different kind of bond between glucose molecules, forming chains that are cross-linked by hydrogen bonds.  Breakdown of Cellulose ∙Differentcellulose Because organisms is link monosaccharides together to form the principal several different polysaccharides. ∙The mostmolecule structural importantin3 are starch, glycogen, and cellulose. ∙Starch cell wallsisofused plants, it for long term energy storage in plants. ∙Can be needs to branched be strong.(amylopectin) or unbranched (amylose). Animals cannot break down cellulose without the help of intestinal bacteria. It is commonly referred to as fiber. Getting Usable Energy In order for cells to obtain energy from polysaccharides, they must be first broken down into monosaccharides. Hydrolysis occurs, breaking the polysaccharide into glucose molecules. 28 The fundamental unit of a polysaccharide can be: A fructose. B glucose. C sucrose. Answer D A and B E I need help D https://njctl.org/video/?v=7-AhBT5VFec  29 Simple sugars do not include A monosaccharides. B disaccharides. C polysaccharides. Answer D glucose. C E I need help https://njctl.org/video/?v=7UWoNU9FX_U  30 Starch and glycogen are similar molecules because A they are both disaccharides. B they are both structural molecules. Answer C they are both used to store energy. C D they are both highly branched. E I need help https://njctl.org/video/?v=jILx2jce8bw  31 A necropsy (an autopsy on an animal) is performed by a veterinarian. The stomach contents contain large amounts of cellulose. We can conclude that this animal is a/an ________________. A carnivore B herbivore Answer C omnivore B D decomposer E I need help https://njctl.org/video/?v=p7aSjcFRtaE  32 In plants ____________ is used for energy storage and ______________ makes cell walls. A glucose; starch B starch; glycogen C starch; cellulose Answer D cellulose; starch C E I need help https://njctl.org/video/?v=Qwy2PZC0WLs  Nucleic Acids Return to Table of https://njctl.org/video/?v=oqgcwEQAgQ0 Contents  Nucleic Acids Nucleic acids are large molecules (polymers) consisting of carbon, hydrogen, oxygen, nitrogen, and phosphorus. They store genetic information and instruct the cell in creating proteins. There are two types of nucleic acids: ∙Deoxyribonucleic Acid, DNA ∙Ribonucleic Acid, RNA The three main types of RNA are: ∙Messenger RNA (mRNA) ∙Transfer RNA (tRNA) ∙Ribosomal RNA (rRNA)  Nucleotides Nucleic acids are composed of chains of nucleotides (monomers). Nucleotides are made up of a sugar, a nitrogenous base, and a phosphate.  Nucleic Acid - DNA A diagram of the nucleic acid, DNA, from Richard Feynman's The Feynman Lectures on Physics, first published in 1963. The two chains of nucleotides are shown. A more contemporary diagram is on the next slide. https://www.feynmanlectures.caltech.edu/I_03.html  Nucleic Acid - DNA This DNA diagram shows more of the bond structure and how the two chains of nucleotides are formed in opposite directions. The bonds and nitrogenous bases between the two sugar-phosphate backbones are also shown - more to follow. https://study.com/cimages/multimages/16/simple_DNA_structure_MT_300px.png The structure and function of DNA will be discussed in greater detail later in the course.  Nucleic Acid - RNA https://upload.wikimedia.org/wikipedia/commons/3/37/Difference_DNA_RNA-EN.s vg RNA is similar to DNA, but only has a single chain of nucleotides (nucleobases). It also has a different sugar and one different base.  Phosphodiester bond The bonds between nucleotides are called phosphodiester bonds. Like bonds between monosaccharides, they are formed by dehydration synthesis reactions. The carbon atoms are numbered, and the 3' carbon of one sugar bonds to the 5' carbon of the adjacent sugar through a phosphate group.  Nucleotide Sugars RNA contains the sugar ribose, while DNA contains the sugar deoxyribose. Ribose Deoxyribose Here's the difference.  Bonds The sugar on one nucleotide covalently bonds with the phosphate on the adjacent nucleotide to form a link in the nucleic acid molecule. The nitrogen bases attach to a base on the other chain with hydrogen bonds.  Bonds The bonds are key to the operation of DNA. The strong covalent bonds in the sugar-phosphate backbone create a strong molecule. The weak hydrogen bonds allow the DNA molecule to be split, copied and then put together - which will be described later.  Bases DNA contains the bases RNA contains the bases adenine, guanine, cytosine, adenine, guanine, cytosine, and thymine (A,G,C,T). and uracil (A,G,C,U). Adenine Guanine Cytosine Thymine Uracil RNA RNA RNA DNA RNA DNA DNA DNA The difference is that DNA uses thymine (T) rather than uracil (U).  Purines and Pyrimidines Nitrogen-containing bases Nitrogen-containing bases composed of 2-ringed composed of 1-ringed structures are known as structures are known as Purines Pyrimidines  DNA DNA is double-stranded. It forms a helix due to the angles of the strong sugar-phosphate bonds. Thymine Hence, it is called a double helix. Adenine Weak hydrogen bonding between nucleotides occurs, but in DNA it is Cytosine between guanine (G) and cytosine (C) and between adenine (A) and thymine (T). Guanine AT CG Nucleotide Sequence Each strand is unique due to its sequence of bases. In this way, genetic information is stored in the sequence of nucleotides. Since the bases are not part of the sugar or the phosphodiester bond, the base sequence is independent of the backbone. Any base sequence is possible.  Double Helix Instead of nucleotides being attracted to other bases in the same strand, to create shapes, they bond to complementary nucleotides in a second strand, to create the double-stranded helix.  RNA RNA molecules are made of single strands of nucleotides. RNA strands folds in on themselves, forming hydrogen bonds between nitrogenous bases, and between the bases and the surrounding water. These bonds cause RNA molecules to form different shapes. Different sequences of bases = different shapes https://njctl.org/video/?v=xAxGeOGw3hQ  RNA Base Pair Bonding Hydrogen bonds form between bases in a predictable pattern. A nucleotide with an adenine base (A) will hydrogen bond with a nucleotide with a uracil (U) base. A nucleotide with a guanine (G) base bonds with a nucleotide with a cytosine (C) base. AU CG  RNA Originally, RNA played many roles that have now been taken over by more specific molecules. RNA's critical function that remains is the creation of proteins. Function Then Now catalyze RNA Enzymes reactions store RNA Mitochondria energy store genetic RNA DNA information  DNA v. RNA Its double helix makes DNA a better archive for genetic information since the bases are protected inside of the helix. Also, thymine is more stable than uracil. But, its helical structure means that DNA can't directly work in the cell. https://upload.wikimedia.org/wikipedia/commons/3/37/Difference_DNA_RNA-EN.s vg It is a library of information, but the only way that information can be used is via RNA. RNA is chemically active in the cell, DNA is not.  Storage and Use of the Genetic Code DNA is useful and stable as an archive RNA is useful working in the cell. DNA is maintained in a safe environment to maintain the integrity of the genetic code. RNA is used throughout the cell to implement the genetic code that is stored within DNA. 33 Identify the monomers in the diagram below. A Nucleic Acid B Nucleotide Answer C I need help B https://njctl.org/video/?v=nD3RoFkKpmY 34 What is a nucleotide composed of? A nitrogenous base Answer B sugar phosphate backbone C sugar D D All the above E I need help https://njctl.org/video/?v=aGoS_gMTE7Q 35 How does RNA differ from DNA? A RNA has one chain of nucleotides, DNA has two. B RNA has two chains of nucleotides, DNA has one. Answer C Only RNA has nucleotides. A D RNA does not have sugars, but DNA does. E I need help https://njctl.org/video/?v=5kh3RWvIkOo  36 The creation of a phosphodiester bond involves the removal of ____ from the nucleotides: A phosphates B glucose Answer C water C D nucleic acids E I need help https://njctl.org/video/?v=gR8K1C4zq8M  37 Which of the following is not a component of a nucleotide? A phosphate group B nitrogenous base Answer C 5-carbon sugar D glucose D E I need help https://njctl.org/video/?v=PYCRLLqSLJU  38 Which base is found in RNA but not DNA? A Cytosine B Uracil C Guanine Answer D Adenine B E I need help https://njctl.org/video/?v=huXWY62wFP0 39 The bonds in the sugar-phosphate backbone are _________, and the bonds between the nitrogenous bases are ________. A strong; strong Answer B strong; weak B C weak; strong D weak, weak E I need help https://njctl.org/video/?v=dJHtUr5cRjI  40 DNA is more stable than RNA because _____. A it can form a double helix B it contains the base uracil C it can form a double helix and contains the base uracil Answer D it can form a double helix and contains the base D thymine E I need help https://njctl.org/video/?v=52vBWcsFryw  41 DNA _______________; RNA _____________. A is a polymer of nucleic acid; is a polymer of glucose B is always a double helix; forms many shapes Answer has hydrogen bonds between its bases; B C bases do not form bonds D acts as an enzyme; stores genetic code E I need help https://njctl.org/video/?v=392R9l32iyM  Amino Acids, Proteins Return to Table of Contents https://njctl.org/video/?v=mgZ51dGsNDg  Proteins Proteins are compounds consisting of carbon, hydrogen, oxygen, nitrogen, and, sometimes, sulfur. Proteins carry out work in an organism. They are the machines, the enzymes, the transporters. They also form some important structures. Proteins are also called peptides and polypeptides.  Amino Acids Proteins are chains of amino acids. There are 20 amino acids used to construct the vast majority of proteins. While there are a few others that are sometimes used, these 20 are the "standard" amino acids. All life on Earth uses virtually the same set of amino acids to construct its proteins.  Components of Amino Acids Amino Acids include an amino group (-NH ), a carboxyl group 2 (-COOH) and a side chain (R-group). Each unique side chain (R-group) determines the properties of its amino acid. carboxyl group (-COOH) amino group (-NH2) Side chain R-group  Peptide Bonds The chemical bond that is formed between amino acids is called a peptide bond. Like bonds between saccharides and nucleotides, they are formed by dehydration synthesis. Hydroxyl group H ion Water  Peptide Bonds This shows formation of a dipeptide by a dehydration synthesis reaction. 1 2 A peptide chain with about 50 or more amino acids can form an individual protein. 2 1 The largest known human protein, Titin, has 34,350 amino acids!  Amino Acids Shown here are the twenty amino acids from which all proteins are comprised. Also shown are the abbreviations of each.  Protein Shape and Structure Shape is critical to the function of a protein. A protein's shape depends on four levels of structure: ∙Primary ∙Secondary ∙Tertiary ∙Quaternary https://njctl.org/video/?v=pNrEMziAm50 Proteins: Primary Structure The primary structure of a protein is the sequence of amino acids that comprise it. Each protein consists of a unique sequence. Alanine Leucine Serine Lysine or Valine Leucine Leucine Alanine or Lysine Alanine Serine Lysine or...  Changes in Primary Structure Changes in the primary structure of a protein are changes in its amino acid sequence. Changing an amino acid in a protein changes its primary structure, and can affect its overall structure and ability to function. Sickle Cell disease is an example of a single amino acid defect, which changes the shape of the hemoglobin protein. Sickle Cell Disease Sickle Cell Disease is a blood disorder specifically involving hemoglobin, which carries oxygen in the blood. A single glutamate amino acid is replaced by a valine in the primary sequence. The result changes the overall shape of the hemoglobin molecule and does not allow it to properly carry oxygen.  Secondary Structure Secondary Structure is a result of hydrogen bond formation between amine and carboxyl groups of amino acids in each polypeptide chain. Depending on where the groups are relative to one another, the secondary structure takes the shape of an alpha helix or a pleated sheet. Note: R-groups do not play a role in secondary structure.  Secondary Structure pleated sheets alpha helix  Tertiary Structure Tertiary Structure is the overall 3-D shape of the polypeptide. It results from interactions of R-groups in alpha helices or pleated sheets. R-groups ∙cluster due to hydrophobic and hydrophilic interactions ∙attract and repel one another due to charge interactions.  Structure Determines Function The function of a protein is determined by its shape, its tertiary or quaternary structure. Protein shape is driven by amino acid chemistry. Protein function is determined by its shape and its surface chemistry. Each sequence of amino acids folds in a different way as each amino acid in the chain interacts with water and the other amino acids in the protein uniquely. For instance, upon contacting water, a protein could form a groove with an arrangement of electrons that functions as a binding site for other molecules.  Protein Structure Level Structure Notes single chain of peptide bonds between Primary amino acids amino acids hydrogen bonds alpha helix, Secondary between amine and pleated sheet carboxyl groups within a peptide clustering of hydrophobic determine Tertiary or hydrophilic R groups, overall peptide charge interactions, S-S shape bridges bonds and interactions not present in Quaternary between multiple peptide all functional chains that hold them proteins together  Quaternary Structure Some proteins have a Quaternary Structure. Quaternary structure consists of more than one polypeptide chain binding together due to multiple bonds and interactions between chains. Tertiary and quaternary structure are often stabilized by covalent bonds called disulfide bridges. They form between sulfur-containing amino acids in the same or different peptides. https://njctl.org/video/?v=DexvcY4krRc  Denaturation Changes in heat, pH, and salinity can cause proteins to denature which means they unfold permanently and lose their functionality. This egg's protein has undergone denaturation and loss of solubility, caused by the high rise in the temperature of the egg during the cooking process.  Types of Proteins Proteins have thousands of different roles in an organism. Eight common categories of function are shown. Type Function or Example Structuralhair, cell cytoskeleton Contractileas part of muscle and other motile cells Storage sources of amino acids or ions Defense antibodies, blood cell receptors Transport hemoglobin, membrane channels Signaling hormones, membrane receptors Enzymatic regulate speeds of reactions Machines motor protein moves organelles, microtubules move chromosomes https://njctl.org/video/?v=MfveksCz0U4  42 Glucose molecules are to starch as ___________ are to proteins. A oils B fatty acids C amino acids Answer D nucleic acids E I need help C https://njctl.org/video/?v=c1CCfUzjRF0  43 Which of the following is not a component of amino acids? A R-group B Amino Group C Hydroxyl Group Answer D Carboxyl Group C E I need help https://njctl.org/video/?v=y-bYRdQ2qaI  44 Which component of amino acids varies between the 20 different types, giving each its unique behavior? A Amine group B Carboxyl group C Hydroxyl group Answer D R-group D E I need help https://njctl.org/video/?v=Kp692XekNvI  45 The tertiary structure of a protein refers to: A its size. Answer B the presence of pleated sheets. C C its overall 3D structure. D the number of R-groups it contains. E I need help https://njctl.org/video/?v=VfyWbXGVUGc  46 The __________ structure of a protein consists of a chain of amino acids assembled in a specific order. A primary B secondary C tertiary Answer D quaternary A E I need help https://njctl.org/video/?v=SywTLSDXJxg  47 Hydrophobic and charge interactions have occurred between R groups of adjacent amino acids in a protein. This has determined the ________ structural level and forms a/an ________. A secondary; alpha helix B secondary; pleated sheet C tertiary; 3D shape D primary; alpha helix Answer C E I need help https://njctl.org/video/?v=STsdhfXGZrM  48 Denaturation causes a protein to A lose its shape. Answer B lose its function. C C Both A and B D None of the above E I need help https://njctl.org/video/?v=sQyoffdMp8Q 49 At which level of folding can a protein become functional? A Secondary B Tertiary Answer C Quaternary D B and C are correct D E I need help https://njctl.org/video/?v=qkMmRCfvzQ4  51 Hemoglobin is an example of what class of proteins? A Transport Answer B Signaling A C Enzymatic D Structural E I need help https://njctl.org/video/?v=MWiuYFVaS30  50 Hormones are an example of what class of protein? A structural Answer D B defense Note- not all hormones are made out of peptides. Many are lipids. C transport D signaling E I need help https://njctl.org/video/?v=Fyzd_k89WRE  Lipids Return to Table of Contents https://njctl.org/video/?v=kaLO9ycdKss  Lipids Lipids are the one class of large biological molecules that do not consist of polymers. Sugars, nucleic acids and amino acids are all polymers. The main functions of lipids include: ∙energy storage ∙the major component of cell membranes ∙various metabolic activities  Molecules and Water Recall the definitions of hydrophobic and hydrophilic. water water Hydrophobic Hydrophilic molecules are molecules not attracted to are attracted water to water  Types of Lipids hydrophilic head Lipids are either hydrophobic or amphiphilic. hydrophobic tail Amphiphilic molecules have a hydrophobic "tail" and a hydrophilic "head." So the hydrophilic end is attracted to water and the hydrophobic is not. Phospholipids are amphiphilic. Fats and oils are hydrophobic lipids, and will not mix with water.  Triglycerides: Hydrophobic Lipids Triglycerides are common fat storage molecules in our bodies. They are hydrophobic. They are constructed from two types of smaller molecules: a single glycerol and three fatty acids. Fatty acids are carboxylic acids with a very long chain of carbon atoms. They vary in the length and the number and locations of double bonds they contain. glycerol a fatty acid CH OH 2 H H H H H H H H H CH OH H C C C C C C C C C COOH 2 H H H H H H H CH OH 2  Triglycerides Three fatty acids are added to glycerol to produce a trigliceride.  Phospholipids: Amphiphilic Lipids Phospholipids have 2 fatty acids and 1 phosphate group. The phosphate end is polar and hydrogen bonds with water. The fatty acids are made of long chains of carbon and hydrogen, making them non-polar. As a result, the phosphate end is hydrophilic and the fatty-acid end is hydrophobic. Overall, phospholipids are amphiphilic.  Phospholipids form Cell Membranes If lipids do not form polymers, how do they form cell membranes? Cell membranes are held together by hydrophobic-hydrophilic interactions. The interior and exterior of a cell are both aqueous, so the polar heads orient toward the interior and exterior. The long, hydrophobic tails orient toward one another, away from water, forming a nonpolar, hydrophobic layer, the interior of the membrane.  Saturated Lipids ∙have the maximum number of hydrogen atoms possible ∙have no double bonds in their carbon chain ∙are solid at room temperature https://njctl.org/video/?v=2vrRk6SNmH8  Lipids and Fats Unsaturated Lipids Unsaturated lipids have one or more double bonds. Oils are examples. They are liquids at room temperature. When hydrogenated (by adding more hydrogen) they become solid and saturated.  Fatty Acid Bonding Structure Saturated fatty acids double bond Unsaturated fatty acids  Trans Fats The chemical process that's used to saturate unsaturated fatty acids can lead to trans fats. These have a double bond that results in a linear chain. These do not form naturally, do not function well in biological systems, and are a health hazard. Trans unsaturated fatty acid (trans fats) trans double bond click here to see a cis double bond video on lipids  Trans Fat: Margarine Margarine is a trans fat that was developed during World War II. Due to a milk and butter shortage, scientists took corn oil and hydrogenated it. The double bonds became single bonds, and a solid was formed.  Health Hazards of Trans Fats Trans fats tend to stay in the bloodstream much longer than saturated or unsaturated fats. Trans fats are much more prone to arterial deposition and plaque formation. Scientists have studied whether trans fats could play a role in the following diseases and disorders: cancer, Alzheimer's disease, diabetes, obesity, liver dysfunction, and infertility. Their role remains unclear.  Amphiphilic Lipids: Soaps and Detergents The hydrophobic end of a soap or detergent is repelled by water, but attracted to other non-polar molecules, like grease and oil. The hydrophilic end of the soap or detergent forms hydrogen bonds with water.  Soaps and Detergents The soap or detergent bonds with many stains (oil, grease, etc.), pulls them from the surface being cleaned and into micelles in the surrounding water. DIRT The water and micelles then go REMOVED down the drain, along with the oil or grease, leaving the surface DIRT clean. fabric detergent being hydrophobic end washed hydrophilic end  Waxes Waxes are effective hydrophobic coatings formed by many organisms (insects, plants, humans) to ward off water. They often consist of 2 long fatty acids connected by oxygen-containing groups.  Steroids Steroids are lipids with backbones that form rings. Examples: ∙Cholesterol is an important component of cell membranes. ∙Male and female sex hormones, testosterone and estrogen, are also steroids. ∙Cortisol is a stress-related hormone.  52 How are lipids different from other large biological molecules? Answer A they do not contain carbon D B they contain oxygen C they are hydrophillic D they are not polymers E I need help https://njctl.org/video/?v=LFWcNACbg90  53 Lipids can be _____. A hydrophobic Answer B amphiphilic C C hydrophobic and amphiphilic D hydrophilic and amphiphilic E I need help https://njctl.org/video/?v=7u6g5LrwrQM  54 A phospholipid is an example of a/an _____. A hydrophobic molecule Answer B hydrophilic molecule C C amphiphilic molecule D hydrophobic and amphiphilic molecule E I need help https://njctl.org/video/?v=2Hms7UhUR-o  55 Fatty acids with double bonds between some of their carbons are said to be: Answer A saturated B B unsaturated C triglycerides D monoglycerides E I need help https://njctl.org/video/?v=qN5W7ZE2Pkc  56 Which of the following is not a lipid? A wax Answer B cellulose B C cholesterol D triglyceride E I need help https://njctl.org/video/?v=AEJKyOLtb2I  57 Cholesterol is a lipid found in cell membranes A True Answer B False A C I need help https://njctl.org/video/?v=Fsc-p55i-2s  58 Which of the following is not one of the four major groups of molecules found in living organisms? Answer A glucose A B carbohydrates C proteins D nucleic acids E I need help https://njctl.org/video/?v=Z2DN3aVHlaw