gene expression and epigenetics Flashcards
it is the collection of mRNAs in a cell
transcriptome
- complete cell of RNA molecules (transcripts)
*mRNA
* non coding RNA (rRNA, tRNA)
[In simple terms, the transcriptome is like a snapshot of all the “messages” (RNA) a cell is sending out at a particular time, showing which genes are active and what the cell is doing or planning to do.]
it occurs over time at the molecular and organ levels
changes in gene expression
single-cell transcriptomics catalogs -
proteomics catalogs -
single-cell transcriptomics catalogs - mRNAs in a cell
proteomics catalogs - proteins in a cell
briefly explain the globin chain switching
hemoglobin is made up of 2 globular protein chains:
- beta chain globin grp
- alpha chain globin grp
*each globin surrounds an iron containing chemical group called heme group
embryonic > fetal > adult
as human develops, different globin polypeptide chains specifically in the hemoglobin r used in the process
what are the implications does the presence of the multiple conformations in hemoglobin have for cellular function is in relation
these different shapes allow hemoglobin to pick up oxygen in the lungs and release it where it’s needed
in all tissues and organs, genes are turned on and off during development. hence, what does the stem cells do
self-renew and yield more specialized daughter cells
exocrine progenitor cell vs endocrine progenitor cell
exocrine progenitor cell:
release digestive enzymes into ducts
endocrine progenitor cell
secrets hormones directly int the blood streams
*endocrine cells clusters are called the islets of Langerhans
it is activated and controls expression of other genes in a way that stimulates some progenitor cells to divide.
transcription factor
to connect disease that shone genes with altered expression
diseasome
- determine how proteins will be related with related functions and which can be rebuilds links between medical conditions
[map shows how different diseases may be related at the genetic level, even if they seem very different]
it can control the functioning of larger proteins
microproteins
- can interact with larger proteins and affect how they work, either enhancing or blocking their functions.
microRNAs
bind to certain mRNAs
preventing their translation into proteins
chromatin remodeling
dna is wrapped arnd histones
these histones can be rearranged to either expose certain parts of dna to transcription factors or keep other parts hidden
exposed parts can be turned on to make proteins, while hidden parts are off
it adds or removes certain small chemical groups to or form histones
chromatin remodeling
what are the 3 major types of small molecules that bind to histones
adds:
acetyls , CH3CO2
- histones play in controlling in expression lies in the acetyl grp
phosphates, PO4-
removes:
methyl, CH3
overall = more fair favorable chromatin structure for transcription, thereby promoting gene expression
what happens when one acetyl groups are added to particular aa in the tails of certain histones
the tata box becomes accessible to transcription factor
these help the small and large protein complexes ease movement of the tata box away from the histones, enabling transcription to proceed
H3and H4
how many base pairs are wrapped around a nucleosome
only 146 base pairs
These changes in gene expression are heritable from cell generation to cell generation, but they do not alter the DNA base sequence
epigenetic
*addition and removal of acetyl, mehyl or phosphate grps
what happens when the chromatin opens to allow transcription factors to bind
microRNAs bind to specific mRNAs
blocking their translation into protein
it is a type of noncoding RNA
MicroRNA
- 21 to 22 bases long
- they do not encode an amino acid sequence
closed chromatin vs open chromatin
closed chromatin
- heterochromatin
- tightly packed
open chromatin
- euchromatin
- ez to read
- loosely packed
__ genes > __ mRNAs > __ proteins
20 325
100 000
1 million
it can fit inside the nooks and crannies of large proteins, such as cell surface receptors and ion channels, affecting their functioning.
microproteins
which is smaller? microproteins or transcription factors
Transcription factors are small, but not nearly as tiny as the microproteins, which are fewer than 100 amino acids long
splicing is also known as
post-transcriptional modification
what are the enzymes used to remove the introns
spliceosomes
this create different forms (isoforms) of protein from the same gene
alternative splicing
A virus mass produces itself using the infected cell’s transcriptional and translational machinery.
viral dna
how many percent of human DNA encode protein
1.5%
- most of the human genome does not encode protein
- non protein encoding part of the genome:
viral sequences
sequences that encode noncoding RNAs
pseudogenes
introns
promoters
other controls
transposons
what enzyme does the retroviruses copy its genetic material into dna, which inserts into a host chromosomes
reverse transcriptase
Some noncoding RNAs correspond to DNA sequences
pseudogenes
- similar in sequence to a protein-encoding gene that may be transcribed, but it is not translated into protein.
function of
viral dna:
NONCODING RNA GENES
tRNA genes:
rRNA genes:
long noncoding RNAs:
pseudo genes:
viral dna:
evidence of past infection
NONCODING RNA GENES
tRNA genes:
connect mRNA codons to aa
rRNA genes:
parts of ribosomes
long noncoding RNAs:
control of gene expression
pseudo genes:
dna sequence v similar to known genes that r not translated
The most abundant type of repeat is a sequence of DNA that can move about the genome
transposon or “transposable element”
