Reading Quiz Questions Flashcards
How many total water molecules are created in the condensation reactions that create a polypeptide chain from three amino acids?
2
Why are α helices and β sheets common folding patterns in polypeptides?
Amino acid side chains are not involved in forming the hydrogen bonds, allowing many different sequences to adopt these folding patterns.
Which of the following changes would you generally expect to have the LEAST effect on a protein?
A valine to leucine mutation.
A threonine to tryptophan mutation.
An arginine to glycine mutation.
An aspartic acid to histidine mutation.
A valine to leucine mutation.
Extracellular proteins are directly exposed to extracellular conditions. To help maintain their specific 3-dimensional shape, the polypeptide chains are often stabilized by:
disulfide bonds
Protein domains are often connected by relatively short lengths of polypeptide called
Intrinsically disordered sequences
Areas of the human genome that are not “protein-encoding exons” include:
A) DNA sequences that ensure transcription of the proper gene at the proper time, level, and space
B)DNA sequences that do not use A, G, C, and T bases.
C) DNA sequences that cannot be packaged into the nucleus.
D)DNA sequences that are repeated and are therefore removed by DNA polymerase with each round of replication.
A
The correct answer is:
“DNA sequences that ensure transcription of the proper gene at the proper time, level, and space.”
Explanation:
Areas of the human genome that are not protein-coding exons include regulatory elements, such as enhancers, promoters, and silencers. These regions help control gene expression, ensuring that the right genes are transcribed at the right time and in the right amount.
A laboratory uses single-stranded DNA probes with fluorescent dyes to detect the presence of cells infected with the human papillomavirus (HPV). This technique is known as…
in situ hybridization
In in situ hybridization (ISH), single-stranded DNA or RNA probes labeled with fluorescent dyes or other markers are used to detect specific nucleic acid sequences in cells or tissues. This technique allows researchers to visualize the presence and localization of specific DNA or RNA sequences within intact cells.
In this case, the laboratory is using fluorescent DNA probes to detect HPV-infected cells, which is a typical application of fluorescence in situ hybridization (FISH).
Chromosome duplication occurs during __________, starting at _________.
interphase; origins of replication
Chromosome duplication occurs during interphase, specifically during the S (synthesis) phase of the cell cycle. This is when DNA replication takes place to ensure that each daughter cell receives a complete set of genetic material.
Replication begins at specific sequences called origins of replication, where the DNA helicase unwinds the double helix, and DNA polymerase begins synthesizing the new DNA strands.
m phase
The M phase (mitosis) is when chromosomes segregate, not duplicate
Which of the following statements is correct?
A)DNA polymerase catalyzes the addition of nucleotides onto the 5’ end of the growing nucleic acid chain.
B)Only prokaryotes have leading and lagging strands.
C)Okazaki fragments are found associated with the lagging strand template.
D) DNA polymerase uses deoxyribonucleoside monophosphates to synthesize a new DNA strand.
C
During DNA replication, DNA polymerase can only synthesize DNA in the 5’ to 3’ direction. This creates a problem on the lagging strand, where replication must occur in short, discontinuous segments known as Okazaki fragments. These fragments are later joined together by DNA ligase.
Why the other options are incorrect:
“DNA polymerase catalyzes the addition of nucleotides onto the 5’ end of the growing nucleic acid chain.”
–Incorrect: DNA polymerase adds nucleotides to the 3’ end, not the 5’ end. DNA synthesis always occurs in the 5’ to 3’ direction.
“Only prokaryotes have leading and lagging strands.”
–Incorrect: Both prokaryotes and eukaryotes have leading and lagging strands during DNA replication.
“DNA polymerase uses deoxyribonucleoside monophosphates to synthesize a new DNA strand.”
–Incorrect: DNA polymerase actually incorporates deoxyribonucleoside triphosphates (dNTPs) (e.g., dATP, dTTP, dGTP, dCTP) during DNA synthesis. The triphosphate form provides the energy needed for polymerization.
