Gene regulation, Cell cycle and meiosis, cell cycle regulation, and cancer Flashcards
Which of the following is TRUE about nucleosomes?
They are formed by histones bound to DNA
H1, H2A, H2B, H3 and H4 histones form nucleosomes
They form metaphase chromosome
Removal of H1 disrupts nucleosome structure
All options are true.
They are formed by histones bound to DNA
Which of the following is NOT TRUE about enhancer sequences?
Enhancers are sequences in the DNA
Enhancers can be present close to or away from the gene they control
Enhancers can be present upstream or downstream of the gene they control
Activator or repressor proteins can bind enhancer sequences
Enhancers are proteins that bind DNA
Enhancers are proteins that bind DNA
What is a direct consequence of mutating p53?
Mutant p53 functions as a phosphatase
Mutation in p53 blocks its function as a transcription factor
Mutant p53 binds operator sequences
Mutation in p53 causes it to function as a kinase
p53 mutation leads to blocking G protein function
Mutation in p53 blocks its function as a transcription factor
Which of the following is TRUE about DNA in a brain cell?
DNA is organized into operons
It has the same genes as in the DNA of a liver cell
Gene expression is activated by lactose
All options are true
DNA is expressed at high levels and codes for proteins
It has the same genes as in the DNA of a liver cell
In Prokaryotes, positive control of gene expression describes high level of gene expression which occurs when:
A repressor protein binds to the operator sequences in the mRNA
Repressor protein is released from the operator sequences in the RNA
Repressor protein binds promoter sequences in the DNA
An activator protein binds to the operator sequences in the DNA
Activator protein is released from the operator sequences in the DNA
An activator protein binds to the operator sequences in the DNA
Which of the following is TRUE about cancer cells?
All options are true.
They accumulate mutations
They do not exhibit anchorage dependence
They acquire the ability to invade and disrupt local and distant tissues
They do not have density dependent inhibition
All options are true.
In which phase given below do sister chromatids separate?
Anaphase of mitosis Metaphase of mitosis Prophase of meiosis II Anaphase of meiosis I Cytokinesis
Anaphase of mitosis
In cells of some organisms, mitosis occurs without cytokinesis. This will result in______
Cells with no S phase Cells with no sister chromatids Cells with 2 nuclei Cells with no microtubules Cells that are unusually small
Cells with 2 nuclei
Which of the following is a TRUE statement?
Sister chromatids separate in Mitosis but not in Meiosis
Crossing over occurs in Mitosis, not in Meiosis
Interphase occurs before Mitosis but not before Meiosis I
Interphase occurs between Meiosis I and Meiosis II
Homologous chromosomes separate in Meiosis I but not in Mitosis
Homologous chromosomes separate in Meiosis I but not in Mitosis
Expression of which gene/s is NOT affected by presence of lactose?
Lac A which codes for trans-acetylase
Expression of all genes given here is affected by presence of lactose
Lac Y which codes for Permease
Lac I which codes for Lac repressor
Lac Z which codes for Beta-Galactosidase
Lac I which codes for Lac repressor
Under the following condition, will the lac operon be expected to be ON (high level expression) or OFF (low level or basal expression): Glucose present, Lactose present
Off
Under the following condition, will the lac operon be expected to be ON (high level expression) or OFF (low level or basal expression): Mutation in promoter such that RNA Polymerase cannot bind; Lactose present, no Glucose
Off
Under the following condition, will the lac operon be expected to be ON (high level expression) or OFF (low level or basal expression): No Glucose, no Lactose
Off
Under the following condition, will the lac operon be expected to be ON (high level expression) or OFF (low level or basal expression): Mutation in CAP (CRP) protein causing it to be nonfunctional; Lactose present, no Glucose
Off
If 2n = 16, how many sister chromatids are in the cells at the end of S phase in the cell cycle?
32
