Cell Division Flashcards
True or false: During metaphase of mitosis, the ploidy of a human cell is 4n.
false, they are still 2n because they have not gained any genetic info
True or false: Heterochromatin is more transcriptionally active than euchromatin.
This statement is false. Heterochromatin is the transcriptionally inactive, tightly-packed form of chromatin. Euchromatin, which is packed more loosely, is more easily transcribed.
In cytokinesis, which type of filaments play a pivotal role in the cleavage furrow?
Actin and myosin
In which stage, if any, does a cell become committed to the cell cycle?
G1 is the most crucial growth phase, making enough organelles and proteins to support two progeny cells. If a cell is able to invest enough resources in doubling the necessary structures and machinery, then it is logical that it is ‘committed’. There are of course situations where the cell cycle is interrupted after this checkpoint, but those circumstances are not common.
If a toxin inhibited histone deacetylase, how would it impact protein expression?
If it inhibited histone deacetylase, it would increase protein expression, not decrease it.
Approximately how many base pairs are there in the average diploid human cell?
6 billion. The human genome contains 3 billion base pairs among its 23 chromosomes (haploid), which doubles to 6 billion base pairs among 46 chromosomes in a diploid cell.
True or false: Euchromatin is more abundant during interphase than during S-phase.
This statement is true. Euchromatin is a loosely organized form of chromatin that predominates during interphase, as this looser structure permits greater access to DNA for replication and transcription. Heterochromatin, a more tightly wound form of chromatin, predominates during cell division and on certain parts of the chromosome, such as centromeres.
What is the job of histone deacetylase?
Histone acetylation adds acetyl groups to histone proteins, a process that serves to make these proteins less positively-charged. This reduces the attraction between the histones and their associated DNA, promoting a loose chromatin structure. Histone deacetylation is the reverse of this procedure and promotes a tightly-packed chromatin structure.
What does histone acetylation do?
Histone acetylation adds acetyl groups to histone proteins, a process that serves to make these proteins less positively-charged. This reduces the attraction between the histones and their associated DNA, promoting a loose chromatin structure. Histone deacetylation is the reverse of this procedure and promotes a tightly-packed chromatin structure.
Which aa residue is most likely acetylated on the histone?
Histone tails are acetylated on positively-charged lysine residues. The addition of an acetyl group reduces the charged interactions between histones and DNA, loosening the chromatin structure.
What following cell types is most likely to express telomerase?
proliferative
The restriction point, or the point at which a cell is committed to undergoing mitosis, is located in which stage of interphase?
The restriction point is a point in G1 of the cell cycle, and after it is passed the cell is committed to division.
True or False: the deactivated X chromosome in eukaryotes does not replicate
False, it does, but it is one of the last to do so
