Chapter 8: Control of Gene Expression Flashcards
Although all of the steps involved in expressing a gene can in principle be regulated, what is the most important stage of control for most genes?
transcription initiation
Which form of control directly influences which mRNA are selected by ribosomes for the synthesis of proteins?
translational control
At any given time, a typical differentiated human cell will express how many of its approximately 19,000 protein-coding genes?
from 5000 to 15,000
The transcription initiation site of a eukaryotic gene is found at which location?
where RNA synthesis begins.
Determine whether the following statement is true or false: A cell can change the expression of its genes in response to external signals.
True
Transplanting the nucleus of an epithelial cell into an egg cell lacking genetic information leads to the formation of ___
a normally developing embryo.
A housekeeping gene is a gene whose cellular function is
important for processes found in all cell types.
Which is the main point of control for regulating gene expression levels?
transcription.
A reporter gene is an experimentally engineered regulatory DNA sequence from a gene of interest that has been fused to a gene that encodes a protein that is easily observed experimentally. Why is this approach useful?
It provides information into where and when a gene is expressed.
Determine whether the following statement is true or false: Master regulators such as Ey in Drosophila are so powerful that they can even activate their regulatory networks outside the normal location.
True
Clinicians and the public are excited about the prospects of replacing damaged and diseased tissues with patient-derived (autologous) cells. Using autologous cells, as opposed to cells from a donor, avoids complications such as immune rejection. What series of steps could lead to the production of smooth muscle cells from the fibroblasts of a patient?
- Obtain fibroblasts 2. Use transcription factors to convert fibroblasts to iPS cells. 3. Grow iPS cells in culture 4. Use transcription factors to convert iPS cells to smooth muscle cells.
In eukaryotes, which parts of a gene are transcribed into RNA?
introns and exons.
In eukaryotes, what must assemble at a promoter before RNA polymerase can transcribe a gene?
general transcription factors.
To begin transcription, eukaryotic RNA polymerase recognizes nucleotide sequences in what region of the DNA?
promoter region.
Activators ____ the amount of transcription Repressors _____ the amount of transcription
increase, decrease
Activators ___ RNA polymerase Repressors ___ RNA polymerase
recruit, block
What determines the nucleotide sequence of a newly transcribed RNA molecule?
complementary base-paring with a DNA during transcription
All of the RNA in a cell is made by what process?
transcription
Which type of RNA is converted into protein for performing its cellular function?
mRNA
In RNA, which nitrogenous base will pair with the base A?
U
In eukaryotes, the initiator tRNA always carries which amino acid?
methionine.
The translation of an mRNA begins at the start codon. What is the sequence of this codon?
AUG
How many nucleotides are necessary to specify a single amino acid?
3
Define
Gene
Genetic Code
Transcription Factor
Promoter
General TXN Factors
TBP
Activators
Repressors
Constitutive Genes
Gene: unit of hereditary information that occupies a fixed position on a chromosome.
Genetic Code: each three nucleotides in a row count as a triplet and code for a single amino acid
Transcription Factor: proteins that recognize and bind to specific short DNA sequences, such that their interaction with these sequences, causally affects expression of genes.
Promoter: DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase and its accessory proteins.
General TXN Factors: are proteins that help to position Pol II correctly on the promoter, the region of a gene where transcription is initiated, pull aside the two strands of DNA and then move Pol II into the elongation mode.
TBP: Transcription is an essential step in using the information from genes in our DNA to … The site on the DNA from which the first RNA nucleotide is transcribed
Activators: A protein that binds to a specific regulatory region of DNA to stimulate transcription of an adjacent gene.
Repressors: A protein that binds to a specific regulatory region of DNA to prevent transcription of an adjacent gene.
Constitutive Genes: is a gene that is transcribed continually as opposed to a facultative gene, which is only transcribed when needed. A housekeeping gene is typically a constitutive gene that is transcribed at a relatively constant level.
