1. General transcription factors -have a particular motif that allows them to in
ID: 71873 • Letter: 1
Question
1. General transcription factors
-have a particular motif that allows them to interact with mRNA
-interact with the RNA polymerase complex to initiate transcription
-mark particular proteins for degradation
-help stabilize mRNAs in the cytoplasm
-assemble at the promoter to help translation
2.
Histone modification:
-can change over time in response to environmental cues, allowing genes to be turned on or off as needed.
-can change over time in response to environmental cues, but this has no effect on gene expression.
-is fixed, but this has no effect on whether genes are expressed.
-is fixed; once a histone is modified, it stays that way and the genes with which it is associated are turned on or off permanently.
-is randomsometimes the lysines are modified and sometimes they’re not, but the state is independent of the environment or cell type.
3.
Epigentic mechanisms of gene regulation ___________ and are ___________.
-are not inherited by daughter cells; permanent
-can be inherited by daughter cells; random with respect to the environment
-are not inherited by daughter cells; reversible and responsive to environmental change
-can be inherited by daughter cells; often reversible and responsive to environmental change
-can be inherited by daughter cells; permanent
4.
miRNAs are _____ in eukaryotes and they are important regulators of _____.
-widespread; the cell cycle
-rare; the cell cycle
-widespread; gene expression
-rare; gene expression
-rare; virus infection
Explanation / Answer
1. General transcription factors interacts with RNA polymerase to initiate transcription.
They bound at promoter region of DNA.Transfer factors, DNA and RNA polymerase forms badal transcription complex and then starts transcription.
So, option B.
2. Option A is correct as histone modification is tightly regulated process helps in cell cycle progression, DNA repair, apoptosis etc. Depending upon the requirements and cell type.
3.option B is correct.it can be inherited by daughter cells and are random with respect to environment.
Because epigenetics is the study of variation in phenotypic traits due to environmental factors. These alterations are dyanamic and cause variation in transcription but can or cannot be heritable.
4miRNA are widespread and and they are important regulator of gene expression
Explanation: miRNA are small non coding RNA which are found in plants,animals and some viruses.they induce silencing of gene and hence alter gene expression.
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