DNA Replication
Mitosis
Cell cycle
Random
DNA Replication
100
What is the function of helicase?
To unwind/separate the helical structure of double-stranded nucleic acid
100
What is the correct sequences of mitosis?
prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
100
What are the three major checkpoints?
G1, G2, M (Spindle)
100
What materials does DNA polymerase require in order to synthesize a complete strand of DNA? Select all that apply.
Inorganic phosphate
All four deoxyribonucleotides triphosphates (containing A, C, T, or G)
ATP
Single-stranded DNA template
3'-OH end of the new DNA strand
All four deoxyribonucleotides triphosphates (containing A, C, T, or G)
Single-stranded DNA template
3'-OH end of the new DNA strand
100
What is the end replication problem and how is it solved?
The end-replication problem states that small stretches of DNA at the 3′ ends of chromosomes cannot be copied because these stretches are not covered by Okazaki fragments. Telomerase places telomeres, non genetic strands of code. The end replication problem causes a progressive shortening of telomeric DNA at each round of DNA replication, thus telomeres eventually lose their protective capacity.
200
This is the enzyme that adds new nucleotide bases to the parent or template strand to form a new DNA strand
What is DNA Polymerase III
200
Anaphase
200
What is the purpose of the G1 checkpoint?
Checks for cell size, growth factors, and DNA damage
“Go”- cell completes the whole cell cycle
“Stop”- cell enters a nondividing (quiescent) state known as G0 phase
200
Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
12%
200
The complimentary strand to a template DNA strand that reads 5’ CAT TAC GCT 3’
3’ GTA ATG CGA 5’
300
What is the function of DNA Ligase?
DNA ligases play an essential role in maintaining genomic integrity by joining breaks in the phosphodiester backbone of DNA that occur during replication and recombination, and as a consequence of DNA damage and its repair.
300
During which phase do chromosomes first become visible?
Prophase
300
This checkpoint sends unrepaired cells to undergo apoptosis.
G2
300
What is the difference between a chromatid and a chromosome?
A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner.
300
What is a histone?
The name of the protein that DNA wraps itself around to form nucleosomes, which then form supercoils, which them forms chromosomes
400
What would the consequences of a denatured of DNA Polymerase I be?
RNA primers would not be removed from DNA. DNA replication will be unsuccessful because the Okazaki fragment's RNA primers will have mismatched base pairs. After multiple rounds of cell division, the mismatched nucleotides that remain after mismatch repair would become permanent, eventually leading to mutations.
400
A cell with 10 chromosomes undergoes mitosis. How many daughter cells are created? ___ Each daughter cell has ___ chromosomes.
2, 10
400
Which checkpoint checks for the completion of DNA replication?
G2
400
p53 is activated by:
Phosphorylation
400
After helicase unzips the genes, these hold the template strands of DNA in place so that they do not wind back up.
single-stranded binding proteins
500
What would happen if topoisomerase no longer functioned?
DNA strands would not separate, they would supercoil and fragment. DNA replication would not occur.
500
During which stages of the cell cycle does a chromosome consist of two identical chromatids?
From the end of S phase in interphase through the end of metaphase in mitosis.
500
Vinblastine is a chemotherapeutic drug often administered to patients suffering from cancer. Vinblastine works by entering cancer cells and binding to tubulin, which is a protein that forms microtubules. Once Vinblastine has bound to tubulin, it inhibits the assembly of microtubules and proper formation of the mitotic spindle. This causes the cell cycle to arrest.
a) Identify and explain two phases of the cell cycle most affected by Vinblastine.
b) Identify the checkpoint that is most likely responsible for arresting the cell cycle.
Metaphase: microtubule attachment to the kinetochore would not happen
Anaphase: since microtubule attachment did not occur, the sister chromatids would not separate
M Spindle Checkpoint
500
Biological structures tend to be composed of smaller units that assemble into more complex structures. Using eukaryotic chromosomes as an example,
a) describe the smaller units and their assembly that leads to the larger, more complex structure of a chromosome.
b) Identify one major function of chromosomes.
DNA→ wraps around histones-->nucleosomes--> forms chromatin--> condenses to form chromosomes
packages DNA, allows for cell division to occur more efficiently, contains genetic info, protects genetic info
500
T/F: All DNA polymerases read from the 3’ to 5’ direction.
false. DNA polymerase I can move in the 5' to 3' direction, connecting to the nicks between the Okazaki fragments and adding nucleotides to the 3' OH of the preceding segments. It eliminates the RNA by migrating in the 5' to 3' direction of the Okazaki fragment. This helps with its proofreading abilities.