Gene Regulation Flashcards
protein production starts at?
transcription
after transcription, what process follows?
translation
T/F only a fraction of genes in a cell are expressed at any one time
True
different cell types arise from gene expression because cells have distinct sets of?
transcription regulators
what do transcription regulators do?
increase or suppress transcription
DNA is made up by nucleotides. What do nucleotides consist of?
sugar-phosphate molecule with a nitrogen containing side group, or base attached to it
what are the 4 different bases which create DNA?
Adenine
Guanine
Cytosine
Thymine
define DNA replication
process of DNA copying itself during cell division
what is the first step of DNA replication?
the opening of the double helix and separation of the DNA strand
which enzyme carries out the first step of DNA replication?
helicase
what is the second step of DNA replication?
the priming of the template strand for duplication
what is the third step of DNA replication?
the formation of the new DNA segment
which enzyme carries out the third step of DNA replication?
DNA polymerase
in eukaryotic cells, what phase does DNA replication occur in during the cell cycle?
S phase
what are three things DNA replication is vital for?
cell growth, repair, and reproduction
define Transcription
synthesis of RNA complementary to a DNA template
RNA synthesis is carried out by which enzyme?
RNA polymerase (Pol II)
Do RNA chains grow in a 3’ to 5’ direction or 5’ to 3’ direction?
5’ to 3’
how many strands of DNA is transcribed at a time?
one
The sequence of bases ATG is significant because?
It is the starting site for transcription
the sequence of bases TAA is significant because?
it is the stopping site for transcription
in eukaryotes, gene transcription is controlled by a?
core promoter
what does a core promoter consist of?
- a transcription start site
- a TATA box (at the -2 5 region)
- a TFIIB recognition element (at the -3 5 region)
regulation of transcription is controlled by?
enhancers
what are enhancers?
DNA sequences containing multiple binding sites
what do enhancers do?
activate transcription independent of their location, distance or orientation with respect to the promoters of genes
an activator protein bound to DNA next to an enhancer functions as what purpose?
attracts proteins to the promoter region to activate RNA polymerase and start transcription
the rate of gene expression can be increased or decreased by the binding of?
Transcription factors (TF)
what are Transcription factors?
either activators or repressors to control the enhancers
The binding of transcription factors ultimately determines what?
how much, if any, of the gene product will be produced
T/F the same gene can be transcribed in multiple ways depending on the amount of transcriptional regulator proteins
True
what are the three chromatin remodeling factors?
ATP-dependent factors histone acetyltransferases (HATs) histone methyltransferases (HMTs)
what are the three cofactors which act at the level of DNA?
mediator
general positive cofactors
cell-specific factors negative cofactors
What are housekeeping genes?
genes used in all cell types and are recognized by activator proteins in all cells
what are cell specific genes?
genes expressed in some cell types or at certain times and are recognized by activator proteins in specific cell types or times
what do Basal Transcription Factors do?
bind to the core promoter?
examples of Basal Transcription Factors:
TBP- TATA box binding protein
TAF- TBP associated factors
Does RNA polymerase II bind to basal factors?
yes
trans acting elements vs cis acting elements
trans can diffuse through cytoplasm and act at target DNA sites on any DNA molecule in cell
cis can only influence expression of adjacent genes on same DNA molecule
trans-acting proteins control transcription from class II ______
promoters
the determination of the type of cell a cell becomes depends on different?
transcription factors
T/F transcription factors remain consistent (on or off) during successive generations of cells
False, TF can turn on at different times during successive generations of cells
T/F TF can affect and change a cell during gene expression which affects the next generation of cells derived from a cell
True
In later generations of a cell, the combination of different transcription factors will determine the _____
cell type
what is mRNA?
protein-coding RNA
what is ncRNA?
non-coding RNA- becomes transcribed to serve various functions
what is rRNA?
ribosomal RNA
helps with protein synthesis
what is tRNA?
transfer RNA
mediator between mRNA and amino acids
what is snRNA?
small nuclear RNA
RNA that form part of the sliceosome
what is snoRNA?
small nucleolar RNA
found in nucleolus, involved in modification of rRNA
what is RNAi?
RNA interference
non-coding RNA involved in regulation of expression
what is miRNA?
micro RNA
involved in regulation of expression
what is siRNA?
small interfering RNA
active molecules in RNA interference
what is lncRNA?
what is it regulated by?
what enzyme transcribes it?
-long noncoding RNA
regulates gene expression
-regulated by transcription factors
-RNA Pol II
T/F lncRNA is a regulator of disease
True
where is the genome located in a cell?
in the nucleus
what is the genome comprised of?
chromosomes
what are the tiny proteins called that DNA wraps around inside chromosomes?
histones
once the mRNA is created from the strand of DNA, the mRNA goes out of the nucleous and brings it to the?
ribosome
what does tRNA do at the ribosome
brings amino acids to the ribosome
once the mRNA is read, what is the resulting formation?
protein
what does a cell use to cause specific gene silencing?
microRNA
how does microRNA carry out gene silencing?
inactivates mRNA
