proteins
This type of covalent bond forms between two amino acids during a dehydration reaction.
What is a peptide bond?
These are the three components that make up a nucleotide.
What are a phosphate group, a five-carbon sugar, and a nitrogenous base?
This enzyme unwinds the DNA double helix by separating the two strands during replication.
What is helicase?
This part of an amino acid determines its unique chemical properties and allows amino acids to be classified as acidic, basic, polar, or nonpolar.
What is the R-group (side chain)?
These two nitrogenous bases are classified as purines and have a double-ring structure.
What are adenine and guanine?
This type of DNA replication produces two DNA molecules, each containing one original parental strand and one newly synthesized strand.
What is semiconservative replication?
A scientist discovers a protein consisting of multiple polypeptide chains that interact to form one functional protein. Identify the level of protein structure demonstrated by these interactions.
What is quaternary structure?
This type of covalent bond forms between the phosphate group on the 5′ carbon of one nucleotide and the hydroxyl group on the 3′ carbon of another nucleotide.
What is a phosphodiester bond?
This enzyme synthesizes short RNA primers that provide a starting point for DNA polymerase to begin DNA synthesis.
What is primase?
A scientist exposes an enzyme to extremely high temperatures and observes that it loses its ability to function. Explain what happened to the enzyme at the molecular level and why it can no longer perform its original function.
What is denaturation? High temperatures disrupt interactions, including hydrogen bonds, that maintain the protein's folded structure. This changes the enzyme's three-dimensional shape, preventing it from functioning properly.
A scientist analyzes a double-stranded DNA molecule and discovers that 30% of its nitrogenous bases are adenine. Using Chargaff's rules, determine the percentages of thymine, guanine, and cytosine.
What are 30% thymine, 20% guanine, and 20% cytosine?
Identify the discontinuously synthesized DNA strand and explain why it must be produced in fragments.
What is the lagging strand? DNA polymerase can only add nucleotides to the 3′ end of a growing strand. Because the DNA strands are antiparallel, the lagging strand must be synthesized discontinuously, away from the replication fork, producing Okazaki fragments.
Draw all of the protein structures levels, label them including any bonds, its dimensions, and if its functional or not.
-primary
-secondary
-tertiary
-quaternary
A scientist discovers a DNA molecule containing an unusually high percentage of guanine and cytosine compared to adenine and thymine. Explain why this DNA molecule would require more energy to separate its two strands than a DNA molecule containing mostly adenine and thymine.
What is that guanine and cytosine form three hydrogen bonds, while adenine and thymine form only two? The greater number of hydrogen bonds between G-C base pairs contributes to the stability of the DNA double helix, requiring more energy to separate the two strands.
A scientist discovers a mutation that prevents DNA ligase from functioning during DNA replication. Predict how this mutation would affect the newly synthesized DNA molecules.
What is that the Okazaki fragments on the lagging strand would not be glued together? DNA ligase normally seals the gaps between adjacent DNA fragments. Without functional DNA ligase, the lagging strand would remain fragmented, while the leading strand would be less directly affected because it is synthesized continuously.