Which is a correct statement about the cell cycle?
a
Nothing happens during the G1 and G2 phases.
b
DNA replicates during cytokinesis of the M phase.
c
The M phase is usually the longest phase.
d
DNA replicates during the S phase of interphase.
Question 17
Assume that two strands of DNA have been separated and that the base sequence on one strand is TTGC. What is the sequence of bases on the complimentary strand?
a
AACG
b
GCTA
c
CGTT
d
GTAC
Question 18
Eukaryotic DNA is packed in a chromatin structure, making it harder than prokaryotic DNA to be transcribed. Which proteins are directly involved in the structure of eukaryotic DNA?
arnold protein meme – Stone Strength Systems Gym
a
histones
b
Actins
c
polymerases
d
collagens
Question 19
Kelvin got his wisdom teeth removed and his mouth is swollen. His doctor tells him to rinse his mouth with a warm saltwater solution every few hours. How does the saltwater solution help heal Kelvin's mouth?
a
The salt water is a hypertonic solution, and the swollen cells in Kelvin's mouth will take in water through diffusion.
b
The salt water is a hypotonic solution, and the swollen cells in Kelvin's mouth will take in water through osmosis.
c
The salt water is a hypertonic solution, and the swollen cells in Kelvin's mouth will release water through osmosis.
d
The salt water is a hypotonic solution, and the swollen cells in Kelvin's mouth will release water through diffusion.
Question about the cell cycle:
Correct statement: d. DNA replicates during the S phase of interphase.
Explanation: During the cell cycle, the G1 (Gap 1) phase is a period of growth before DNA replication, and the G2 (Gap 2) phase is a period of growth and preparation for cell division after DNA replication. In the S (Synthesis) phase, DNA is replicated. The M (Mitosis) phase is usually the shortest phase and involves the division of the cell's nucleus, and cytokinesis is the process that divides the cell's cytoplasm, forming two daughter cells. Therefore, DNA replication occurs in the S phase, not during cytokinesis of the M phase.
Question about complementary DNA sequence:
Correct complementary sequence: a. AACG
Explanation: The base-pairing rules for DNA state that adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Thus, if one strand of DNA has the sequence TTGC, the complementary strand would be AACG.
Question about eukaryotic DNA structure:
Correct proteins involved in the structure of eukaryotic DNA: a. histones
Explanation: Eukaryotic DNA is wrapped around proteins called histones, which help condense the DNA into a compact structure called chromatin. This packaging allows for the organization of DNA within the cell nucleus and regulates the accessibility for transcription.
Question about saltwater solution for healing:
Correct function of the saltwater solution: c. The salt water is a hypertonic solution, and the swollen cells in Kelvin's mouth will release water through osmosis.
Explanation: A hypertonic saltwater solution has a higher concentration of salts than the fluids within the cells in Kelvin's mouth. When Kelvin rinses with this solution, water will move out of the swollen cells into the saltwater solution through osmosis, aiming to equalize the solute concentration on both sides of the cell membranes. This process can help reduce the swelling.