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Questions and Answers
Which polymers are composed of amino acids?
Which polymers are composed of amino acids?
Proteins
Which of the following is not attached to the central carbon atom in an amino acid?
Which of the following is not attached to the central carbon atom in an amino acid?
- An oxygen (correct)
- A hydrogen
- An amino group
- A carboxyl group
Which part of an amino acid is always acidic?
Which part of an amino acid is always acidic?
Carboxyl functional group
Which monomers make up RNA?
Which monomers make up RNA?
Which of the following statements about the formation of polypeptides from amino acids is true?
Which of the following statements about the formation of polypeptides from amino acids is true?
Enzymes in the digestive tract catalyze hydrolysis reactions.
Enzymes in the digestive tract catalyze hydrolysis reactions.
A dehydration reaction (or condensation reaction) is the process in which _____.
A dehydration reaction (or condensation reaction) is the process in which _____.
The four main categories of large biological molecules present in living systems are _____
The four main categories of large biological molecules present in living systems are _____
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?
Plant cell walls consist mainly of _____
Plant cell walls consist mainly of _____
A molecule with the chemical formula C6H12O6 is probably a _____
A molecule with the chemical formula C6H12O6 is probably a _____
The molecule shown is ________.
The molecule shown is ________.
Which of these is NOT a lipid?
Which of these is NOT a lipid?
This figure is an example of a(n) _____
This figure is an example of a(n) _____
Which of these is a phospholipid?
Which of these is a phospholipid?
Which of these is rich in unsaturated fats?
Which of these is rich in unsaturated fats?
A function of cholesterol that does not harm health is its role _____
A function of cholesterol that does not harm health is its role _____
How many fatty acids are in a phospholipid?
How many fatty acids are in a phospholipid?
What functional feature(s) does the phosphate group contribute to the structure of a phospholipid?
What functional feature(s) does the phosphate group contribute to the structure of a phospholipid?
What holds phospholipids together in a bilayer formation?
What holds phospholipids together in a bilayer formation?
Which molecule is less soluble in water--a fat or a phospholipid? Why?
Which molecule is less soluble in water--a fat or a phospholipid? Why?
The characteristic that all lipids have in common is that _____.
The characteristic that all lipids have in common is that _____.
What makes lipids/fats hydrophobic?
What makes lipids/fats hydrophobic?
The molecule illustrated in the figure ________.
The molecule illustrated in the figure ________.
Proteins are polymers of _____
Proteins are polymers of _____
What type of bond joins the monomers in a protein's primary structure?
What type of bond joins the monomers in a protein's primary structure?
Which of these illustrates the secondary structure of a protein?
Which of these illustrates the secondary structure of a protein?
The secondary structure of a protein results from _____
The secondary structure of a protein results from _____
Tertiary structure is NOT directly dependent on _____
Tertiary structure is NOT directly dependent on _____
Some regions of a polypeptide may coil or fold back on themselves. This is called _____, and the coils or folds are held in place by _____.
Some regions of a polypeptide may coil or fold back on themselves. This is called _____, and the coils or folds are held in place by _____.
A hydrophobic amino acid R group (side group) would be found where in a protein?
A hydrophobic amino acid R group (side group) would be found where in a protein?
A glycosidic linkage is analogous to which of the following in proteins?
A glycosidic linkage is analogous to which of the following in proteins?
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
The chemical reaction illustrated ________.
The chemical reaction illustrated ________.
Your body contains tens of thousands of different proteins, each with a specific structure and function. The unique three-dimensional shape of each of these diverse proteins is based on several superimposed levels of structure. Which of the following statements is an accurate description of proteins?
Your body contains tens of thousands of different proteins, each with a specific structure and function. The unique three-dimensional shape of each of these diverse proteins is based on several superimposed levels of structure. Which of the following statements is an accurate description of proteins?
Identify the level(s) of protein structure present in this molecule.
Identify the level(s) of protein structure present in this molecule.
What could happen if a mutation in a gene caused a hydrophobic amino acid in a polypeptide to be replaced by a hydrophilic amino acid?
What could happen if a mutation in a gene caused a hydrophobic amino acid in a polypeptide to be replaced by a hydrophilic amino acid?
If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?
If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?
If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?
If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.
A nucleotide is composed of a(n) _____
A nucleotide is composed of a(n) _____
When nucleotides polymerize to form a nucleic acid _____
When nucleotides polymerize to form a nucleic acid _____
Which of the following is a major difference between RNA and DNA?
Which of the following is a major difference between RNA and DNA?
Identify three possible components of a DNA nucleotide.
Identify three possible components of a DNA nucleotide.
These figures show the four levels of protein structure: primary, secondary, tertiary, and quaternary structure. Which level of protein structure is characteristic of some, but not all, proteins?
These figures show the four levels of protein structure: primary, secondary, tertiary, and quaternary structure. Which level of protein structure is characteristic of some, but not all, proteins?
Study Notes
Proteins and Amino Acids
- Proteins are polymers made of amino acids.
- In amino acids, an oxygen atom is not attached to the central carbon atom.
- The carboxyl functional group is always acidic in an amino acid.
- Polypeptides form when the carboxyl group of one amino acid bonds with the amino group of another.
Nucleic Acids
- RNA is composed of nucleotides.
- DNA has a complementary strand based on base pairing rules, e.g., 5'-ATTTGC-3' matches 3'-TAAACG-5'.
- DNA is made of nucleotides consisting of a phosphate group, nitrogenous base, and five-carbon sugar.
Biological Molecules
- Large biological molecules include proteins, nucleic acids, carbohydrates, and lipids.
- Cell walls of plants are primarily made of cellulose.
Lipids
- Lipids are defined by their inability to dissolve in water.
- Fats contain three non-polar fatty acids, making them less soluble than phospholipids, which have a polar head.
- Phospholipids comprise a phosphate group, glycerol, and fatty acids, contributing to membrane structure.
Chemical Reactions in Biomolecules
- Hydrolysis reactions in the digestive tract are catalyzed by enzymes.
- A dehydration (condensation) reaction produces water when forming polymers from monomers.
- Glycosidic linkages in carbohydrates are analogous to peptide bonds in proteins.
Protein Structure
- Proteins exhibit four levels of structure: primary, secondary, tertiary, and quaternary.
- The primary structure is the linear sequence of amino acids coded in DNA.
- Secondary structure results from hydrogen bonding; coils and folds are held by these bonds.
- The tertiary structure is influenced by various interactions, including hydrophobic interactions of amino acid R groups.
- Quaternary structure involves multiple polypeptide chains interacting, seen in some but not all proteins.
Characteristics of Amino Acids
- A hydrophobic R group in an amino acid is typically found on the inside of a folded protein, away from water.
- Mutations affecting R groups can alter protein structure and function due to changes in interactions.
Nucleotide Composition
- A DNA nucleotide can consist of deoxyribose, a phosphate group, and a nitrogenous base like thymine.
- RNA nucleotides differ from DNA due to their sugar type.
Structural Stability
- Proteins retain primary structure even when hydrogen bonds are disrupted.
- Hydrogen bonds between nitrogenous bases connect the two strands of DNA, stabilizing the double helix.
Fatty Acids and Cholesterol
- Saturated fats have no double bonds in their fatty acid tails, while unsaturated fats contain double bonds.
- Cholesterol is crucial as a component of animal cell membranes, contributing to membrane stability.
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Description
Test your knowledge on essential concepts from Chapter 5 of MasteringBiology. This quiz covers topics such as amino acids, proteins, and RNA structure. Perfect for students looking to reinforce their understanding of biological macromolecules.
