gene transcription and micro Flashcards
Heterochromatin=
euchromatin =
heterochromatin= dense, inactive
euchromatin= disperse, active
most proteins in chromatin are
histones
RNA differs from DNA in that it has
ribose instead of deoxyribose and uracil instead of thymine
What is the product of gene transcription?
mRNA
-carries the code for protein synthesis
can mRNA leave the nucleus?
Yes, to take DNA code to the ribosomes
Where are rRNA found
found on ribsomes
what carries amino acids that are used for protein sysnthesis in the ribosome?
tRNA
What are snRNA
-involved in transcriptional regulation and mRNA processing
-part of spliceosome machine
-first made of ribonucleotides, then folds into 3D structure
what is the exception to the central doga
some viruses
Central dogma: flow of information from DNA to RN
What is the genetic code
the dictionary that gives the correspondence between a sequence of nucleotide bases and a sequence of amino acids
3 nucleotides bases = codon
61 of 64 codons code for the 20 AA
3 stop codons
stop codons
UAA, UAG, UGA
start codon
AUG, methionine
In protein synthesis, in transcription, what is the first step
chromatin remodeling
breaking bonds of DNA
Allows for template strand to be exposed for RNA transcriptin
RNA polymerase II needs other proteins called transcription factors to be able to bind to the DNA. What is its name and what steps come after
TFIID
1. First bind TFIID to the TATA box
What is the promoter region
the promoter region is the region where basal transcriptional machinery attaches
The TATA box is on the promoter region and TFIID binds here first
What do enhancers do
increase transcription levels
responds to cell needs and stage of embryological development
activators attach to the _______ region to activate transcription of the region
enhancer
silencers
decrease transcriptional levels.
_______ attach to silencer region to inhibit transcription of the region
repressors
T/F Pol II can bind directly to DNA
False. TFIID needs to bind to TATA, only then Pol II can bind
Methods of post-transcriptional modification of (pre-)mRNA
- modify strand of pre mRNA after transcription (introns out, exons in)
- 7-mG methyl guanosine tail (protects mature mRNA from nuclease attck)
- Poly-A tail (keeps mRNA stable)
Why are introns important
important signaling sequences
Where does translation take place
at ribosomes
40 S small and 60S large which combine to form 80S ribsome.
each tRNA has an __________ loop complimentary to the codon on the mRNA
anti-codon
- the AA has to be activated with ATP via aminoacyl-trna synthetase so it can attach to correspondinf tRNA to become charged
name two distinct features on the structure of tRNA
anticodon, and AA binding site
What is the point of glycosylation?
-form of post translational modification
-assists in protein folding to reach its correct shape.
-enhances protein solubility
-stabilizes the protein against denturation
-protect the protein from proteolytic degradation
-target the protein to specifc subcellular locations
Micro nomenclature
Two names: genus and species
genus capitlized species not
both names are underlines or italicized
nomenclature exception: viruses
Three domains
Bacteria, Archea, Eukaryota
Archae: constitute a domain of single-celled organisms, lack nuclei, and are therefore prokaryotes
bacteria: unicellular, genetic material not enclosed in a nuclear membrane. Can be rod shapes, spherical, corkscrew, star shapes
Eukaryotes (fungi, algae, protozoa, multicellular parasites, animals): distint nucleus, nuclear membrane, unicellular or multicellular
What organelles are absent in prokaryotes
mitochondria, golgi, ER,
a bacteria lacking a cell wall is called
mycoplasma
Viruses are dependent on a ____ cell and (are/are not) living things
host cell; not living
What is anatomic position
stands upright, feet flat, palms facing anteriorly
planes of reference
coronal
tranverse
midsagittal
coronal: sliding a glass from shoulder to shoulder, divides body into anterior and posterior
transverse: cutting front to back of stomach, tween legs
co
