D2.2 Gene Expression Flashcards
Identify which of the following is likely to increase the persistence of mRNA in a cell.
I. increased levels of nucleases
II. the presence of stabilising molecules
III. the addition of a poly-A tail
2 and 3 only
Identify the likely result of two genes sharing a promoter.
They are likely to be transcribed together.
May have related functions.
Enhancers are ________ of DNA that play a role in _____ when and to what extent a gene is expressed. They do this during _______.
specific regions, regulating, transcription
When an activator protein binds an enhancer, it forms a ____ that interacts with the promoter, making it easier for RNA polymerase to ___.
complex, bind
Epigenesis definition
process by which cells and organisms develop from an undifferentiated zygote through the interaction between DNA and environmental factors.
Which group added during methylation?
CH3 (methyl group)
Methylation of ________ in the DNA of a promoter represses transcription because it _____ transcription factors from binding.
cytosine, prevents
When can epigenetic changes can be inherited?
If they occur in germline cells
- or maintained through meiosis
What can affect the phenotype of cells and organisms.
diet, exposure to air pollution, temperature.
Hormone oestradiol.
I. It is a steroid hormone and so is able to move freely through cell membranes.
III. Once bound to a receptor, it can move into the nucleus and bind directly to DNA, modifying gene expression.
monozygotic twins.
genetically identical individuals; useful for studying the effect of the environment on gene expression.
gene-specific DNA
segment of DNA (codes for protein
Transcription factor
DNA binding protein- controls transcription by binding to enhancer or silencer
promoter
RNA polymerase binds to start transcription
enhancer
base sequence that promote transcription when transcription factor binds
silencer
base sequence that inhibit transcription when a transcription factor binds
Mature mRNA has:
5’ cap at the front
-mRNA
-Poly A tail
The Poly-A tail ________ at varying rates.
- short tailed mRNA: ______________
-vulnerable to _________
degrades, less likely to be translated, degradation
lengths of poly-A tail determines how many _______ are made.
Long tail = ______
Short tail = ______
- can also be controlled by _____
proteins, many proteins, few proteins, hormones
Epigenetic tags:
Chemical modification that causes some genes (activated), others (silenced)
Epigenetic tags don’t affect genes. They ONLY affect ________.
pattern of expression
Genome:
all base sequences (DNA info.)
Transcriptome:
all mRNA sequences
Proteome
all of the proteins produced by a cell.
