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Questions and Answers
Which level of protein structure involves regular coils and folds formed by hydrogen bonds?
What describes the tertiary structure of a protein?
What role does the sequence of amino acids play in protein structure?
Why is the primary structure of a protein important?
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What is the primary structure of a protein?
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What type of bonds are primarily responsible for forming the secondary structures of proteins?
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Which statement best describes the tertiary structure of a protein?
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What is the composition of collagen?
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Which of the following interactions is NOT involved in tertiary protein structure?
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What is the primary role of fats in the human body?
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What causes sickle-cell disease at the molecular level?
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Which property of phospholipids allows them to form a bilayer in cell membranes?
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What structure characterizes steroids?
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What role do enzymes play in biological processes?
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What is the monomer unit used to build proteins?
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Which of the following statements about polypeptides is true?
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How do amino acids differ from one another?
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What is the consequence of high cholesterol levels in the blood?
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What type of reaction is involved in forming disaccharides from monosaccharides?
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Which of the following is a storage polysaccharide found in animals?
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What distinguishes the structure of starch from cellulose?
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Which of the following statements about cellulose is correct?
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What is the main reason humans cannot digest cellulose?
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What is a significant structural feature of cellulose compared to starch?
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Which polysaccharide is composed of glucose monomers and has a storage function in plants?
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What relationship do many herbivores have with microbes regarding cellulose?
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What is the term for the loss of a protein's native structure due to environmental factors?
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Which of the following proteins assists in the proper folding of other proteins?
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Which of the following is NOT a characteristic of nucleotides?
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What is the main role of messenger RNA (mRNA)?
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What structural feature describes the DNA double helix?
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Which of the following nitrogenous bases is found in RNA but not in DNA?
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Which method is NOT typically used to determine protein structure?
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What do genes primarily encode?
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What is the role of the sugar-phosphate backbone in nucleic acids?
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Which nitrogenous base pairs with adenine in RNA?
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Which of the following statements is true regarding polynucleotides?
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What is the unit of inheritance that programs the amino acid sequence of polypeptides?
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What common feature do both DNA and RNA share?
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What term describes the pairing of nitrogenous bases in DNA?
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Study Notes
Dehydration Synthesis
- Forms larger molecules from smaller monomers by removing water
- Example: Glucose + Glucose = Maltose (disaccharide)
Disaccharides
- Two monosaccharides joined by a glycosidic linkage
- Examples:
- Maltose (Glucose + Glucose)
- Sucrose (Glucose + Fructose)
- Lactose (Glucose + Galactose)
Polysaccharides
- Polymers of sugars with storage and structural roles
- Structure and function determined by:
- Sugar monomers
- Positions of glycosidic linkages
Storage Polysaccharides
- Starch (Plant):
- Made of glucose monomers
- Stored as granules in chloroplasts and other plastids
- Glycogen (Animal):
- Found in liver and muscles
Structural Polysaccharides
- Cellulose:
- Major component of plant cell walls
- Polymer of glucose with different glycosidic linkages than starch
- Uses beta (β) glucose
- Differences in glucose ring forms:
- Alpha (α) glucose: helical polymers
- Beta (β) glucose: straight polymers
- Cellulose structure:
- Straight structure allows hydrogen bonding between strands
- Forms strong microfibrils for plant structure
- Humans lack enzymes to digest beta (β) linkages in cellulose
Lipids
- Diverse group of hydrophobic molecules
- Major functions:
- Energy storage
- Structural components of cell membranes
Fats
- Store energy for long-term use
- Triglycerides composed of glycerol and three fatty acid tails
- Adipose tissue stores fat in animals
Phospholipids
- Amphipathic molecules
- Two fatty acid tails (hydrophobic) + phosphate group (hydrophilic)
- Form bilayers in water to create cell membranes
Steroids
- Four fused ring structure
- Cholesterol:
- Important component of animal cell membranes
- Can contribute to cardiovascular disease at high levels
Proteins
- Account for more than 50% of cell dry mass
- Diverse functions:
- Structural support
- Storage
- Transport
- Cellular communications
- Movement
- Defense
- Polymers of amino acids (polypeptides)
Amino Acids
- Monomers of proteins with:
- Carboxyl group
- Amino group
- Central carbon
- Variable side chain (R group)
- 20 different amino acids due to different R groups
Polypeptides
- Unbranched polymers of amino acids
- Covalent bonds between amino acids called peptide bonds
- Unique linear sequence of amino acids
- Have carboxyl end (C-terminus) and amino end (N-terminus)
Protein Structure
- Determines protein function
- Four levels:
- Primary: Sequence of amino acids
- Secondary: Coils (alpha helices) and folds (beta pleated sheets) due to hydrogen bonding
- Tertiary: Folding due to R group interactions (hydrogen bonds, ionic bonds, hydrophobic interactions, van der Waals interactions, disulfide bridges)
- Quaternary: Multiple polypeptide chains forming one macromolecule
Sickle-Cell Disease
- Caused by a single amino acid substitution in hemoglobin protein
- Affects protein structure and function
Protein Folding
- Chaperonins assist in proper protein folding
- Misfolded proteins can cause diseases like Alzheimer's, Parkinson's, and mad cow disease
Nucleic Acids
- Store and transmit hereditary information
- Two types:
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
DNA
- Directs its own replication
- Directs synthesis of messenger RNA (mRNA)
- Controls protein synthesis
RNA
- Transports genetic information from DNA to ribosomes
- Plays a role in protein synthesis
Nucleotides
- Monomers of nucleic acids
- Components:
- Nitrogenous base
- Pentose sugar
- Phosphate group
- Nucleoside: Without phosphate group
Nitrogenous Bases
- Two families:
- Pyrimidines: Cytosine (C), Thymine (T), Uracil (U)
- Purines: Adenine (A), Guanine (G)
DNA vs. RNA
- DNA sugar: Deoxyribose
- RNA sugar: Ribose
- DNA bases: A, T, C, G
- RNA bases: A, U, C, G
Nucleic Acid Structure
- Polynucleotides: Polymers of nucleotides
- Covalent bonds between nucleotides form a sugar-phosphate backbone
- Sequence of bases is unique for each gene
DNA Structure
- Double helix with two antiparallel polynucleotide strands
- Complementary base pairing:
- A with T (in DNA)
- G with C
- Hydrogen bonds between bases hold strands together
RNA Structure
- Usually single-stranded
- A with U (in RNA)
- G with C
- Can form complementary base pairing with itself or other RNA molecules
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Description
Explore the fascinating world of carbohydrates through this quiz on dehydration synthesis, disaccharides, and polysaccharides. Understand the roles of different sugars and their arrangements in forming complex structures like starch and cellulose. Test your knowledge on the building blocks of life!