Question 1

Which molecule shown in the first image (A, B, C, D) would be found in DNA, and what is its classification?

Accepted Answer

D; deoxyribonucleotide

Question 2

During the formation of a phosphodiester bond in DNA synthesis, which statement about Gibbs free energy ($$\Delta G) is $$correct?

Accepted Answer

Formation of the phosphodiester bond has a positive $$\Delta G$$, and breaking the phosphate-phosphate bond has a negative $$\Delta G.$$

Question 3

Which process produces RNA that is complementary to the DNA template strand?

Accepted Answer

Transcription

Question 4

Where in a eukaryotic cell does the synthesis of a water channel protein destined for the plasma membrane occur?

Accepted Answer

Ribosomes at the rough ER

Question 5

Which of the following is the correct sequence for gene expression regulation as shown in the second image?

Accepted Answer

DNA → mRNA → protein → activated protein

Question 6

Which enzyme catalyzes the bond between monomers during DNA synthesis?

Accepted Answer

DNA polymerase

Question 7

A mutation changes a codon from GGG to GAG in mRNA. What is the most likely effect on the protein?

Accepted Answer

Single amino acid change; the two codons call for different amino acids.

Question 8

Which type of RNA matches an amino acid to the correct codon during translation?

Accepted Answer

tRNA

Question 9

In prokaryotic cells, why can transcription and translation occur simultaneously?

Accepted Answer

Prokaryotic cells lack a nucleus, so ribosomes can associate with mRNA as it is being built.

Question 10

Which regulatory mechanism allows for the most rapid appearance of activated protein in a cell?

Accepted Answer

Post-translational regulation

Question 11

What is an operon in prokaryotic cells?

Accepted Answer

A region of DNA that codes for a set of genes that are transcribed together as a single mRNA.

Question 12

When lactose levels in E. coli are high, how does that increase expression of the lac operon?

Accepted Answer

Lactose binds to the repressor, causing it to detach from the operator. With the repressor out of the way, RNA polymerase can transcribe the operon.

Question 13

Which chromatin modification is associated with increased transcription in eukaryotes?

Accepted Answer

Acetylation of histones

Question 14

Which statement about global gene regulation in bacteria is correct?

Accepted Answer

Genes in a regulon are controlled by a single type of regulatory protein.

Question 15

Which mechanism allows eukaryotic cells to produce more than one version of a protein from the same gene?

Accepted Answer

Alternative splicing

Question 16

A cell that is diploid has how many of each chromosome?

Accepted Answer

Two

Question 17

Which cellular process is responsible for Mendel's Law of Segregation and Law of Independent Assortment?

Accepted Answer

Meiosis

Question 18

In a breed of dog, black (B) is dominant and brown (b) is recessive. If two Bb dogs are crossed, what is the expected phenotype frequency in their offspring?

Accepted Answer

$$\frac{3}{4}$$ black : $$\frac{1}{4}$$ brown

Question 19

A researcher finds that a gene is expressed in one culture condition but not another. Both mRNA and protein are absent in the non-expressing condition. What type of regulation is most likely?

Accepted Answer

Transcriptional regulation

Question 20

In human blood typing, the IA and IB alleles are codominant, and both are dominant to the i allele. If a woman with genotype IB i R r and a man with genotype IA i R r have a child, what is the probability the child will have type A negative blood?

Accepted Answer

$$\frac{1}{16}$$

Identifying Biological Molecules: DNA, RNA, and Proteins

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