Regulation of Gene Expression Review Flashcards
chromosome
- organized structure of DNA and found in cells
- singular piece of DNA, containing many genes, regulatory elements, and other nucleotide sequences
- also contain DNA-bound proteins to pack DNA and control its functions
Does the number of chromosomes have an affect on body size or IQ?
No
What is a gene?
Region of chromosomal DNA that can be made into RNA
Where is DNA located?
- Nucleus -> combination of both parents
- Mitochondrial -> Mother only
What happens to sperm mitochondria after fertilization?
It is destroyed
Properties of DNA
- Repeating Deoxyribose of A, T, G, and C
- Phosphate
- Nitrogen Base
DNA Structure
- Double Helix
- Right handed -> curves upward to right
- Sugar Phosphates -> backbone; outside of helix
- Bases (A,T,C,G) -> Face inward; form “steps”
Purines
Adenine and Guanine
Pyrimidines
Cytosine and Thymine
Adenine pairs with ______ in DNA
Thymine
Guanine pairs with ______
Cytosine
Hydrogen bonds between G & C
3 hydrogen bonds
Hydrogen bonds between A & T
2 hydrogen bonds
To which end of a DNA strand are nucleotides added?
3’ end
Therefore synthesis is 5’ -> 3’
What does DNA Polymerase do?
Adds Nucleotides to 3’ end during DNA Replication
The lagging strand in DNA replication is grown 3’ -> 5’, but DNA Polymerase only works in 5’ -> 3’. How is this problem solved?
- Okazaki fragments
- Fragments are then joined by DNA Ligase in the 3’ -> 5’ direction
Exonuclease
- degrades nucleic acid
- works 3’ -> 5’
Mutation types in DNA replication
addition, subtraction, and substitutions
Mutations, changes that occur during DNA replication, may be….
- lethal
- silent
- beneficial
What is transcription?
- process by which DNA is copied into RNA using RNA Polymerase
- Occurs in 5’ -> 3’ Direction
Coding Strand
- Always same strand (3’ -> 5’)
- Used to generate RNA Strand
Non-coding Strand
RNA sequence will be the same as this sequence
promotor
region of DNA that initiates transcription of a particular gene
Adenine binds to _______ in RNA
Uracil (U)
How does transcription termination occur in bacteria?
Hair-pin Loop
Where does RNA Processing occur? What does it result in?
- Occurs in Nucleus
- Results in mature RNA Strand
Capping
RNA Process that adds a cap to the 5’ end of primary RNA
Poly-A Tail
- Added to the 3’ end of RNA
- protects mRNA from degradation by exonucleases
- essential for transcription termination, export of mRNA from nucleus, and for translation
Introns
- non-coding regions of a gene
- NOT present in mature RNA Transcript
- Removed in nucleus
Exons
- coding regions of a gene
- can be spliced
tRNA
- transfer RNA
- binds one specific amino acid
- each recognizes 1 or more mRNA sequence (genetic code)
rRNA
- ribosomal RNA
- along with protein, makes up ribosomes
- orients mRNA, tRNA, and amino acid complex
- ensure accurate reading of genetic code
mRNA
- messenger RNA
- contains info for translation into proteins
- very high turnover rate
- allows for amplification of genetic message through multiple copeis
Translation
conversion of mRNA into Protein
A Site (Aminoacyl)
binds newly arriving tRNA
P Site (Peptidyl)
carries the growing peptide chain attached as a peptidyl-tRNA complex
E Site (Exit)
tRNA exit from ribosome
Ribosome reads the mRNA sequence to determine the amino acid sequence. It reads 3 nucleotides at a time. What are the 3 nucleotides refer to as?
Triplet Codon
How many codons are possible?
64 possible codons
Start Codon
AUG
-also codes for Methionine
Stop Codons
- UAG
- UGA
- UAA
What is glycosylation?
- enzyme-directed site-specific process (glycosyltransferases)
- occurs in ER and Golgi apparatus
- Folding, targeting, and function of the protein
- donor molecules: nucleotide sugars (ex- ADP-glucose)
- acceptor residues: asparagine (N), serine (S), and theronine (T)
3 Steps of PCR
- Denaturation = separates DNA strands
- Annealing = primers bind DNA
- Extension = new DNA synthesized
Oswald Avery proved that DNA contains the genetic info by studying transformation of…
Bacteria
Actinomycin D is an inhibitor of…
Transcription
What genetic disease is caused by mutations that disrupt alternative splicing sites?
IGHD2 (Familial isolated growth hormone deficiency type 2)
Most abundant protein in the animal body?
Collagen
Supravalvar aortic stenosis is caused by ______ gene mutation
Elastin
Adherens junctions use _______ to form the focal contact between 2 adjacent cells
Integrins
____-actin is muscle specific
Alpha-actin
Toll-like receptors are analogues of ________ in vertebrate innate immune systems
IL-1
Alpha 1-anti trypsin deficiency causes what in dogs?
Panniculitis
Which TLR recognizes LPS?
TLR 4
What is LPS?
Lipopolysaccharide - a component of (mostly gram-negative) bacteria cell walls
Which TLR recognizes flagellin?
TLR 5
