chapter 10 11 12 Flashcards
composition of DNA
phosphate group
deoxyribose sugar: has OH group
nitrogenous base
nitrogenous bases
adenine
guanine
cytosine
thymine
purine
cytosine
thymine
1 ring structure
pyrimidine
adenine
guanine
2 ring structure
guanine and cytosine are
triple hydrogen base bonds
dna shape
double helix
dna runs
antiparallel
5-3
3-5
DNA vs RNA
dna: stable
rna: unstable
rna composition
ribose sugar
nitrogenous base
phosphate group
single-stranded but can fold on top of itself to form LP
nitrogenous bases of RNA
adenine
uracil
gunaine
cytosine
genome
entire genetic information of an organism
all genetic info is contained in
chromosomes
dna replication occurs
every time cell divides
semi conservative
mrna transcription occurs
only if gene needs to be expressed
gene
segment of DNA that encodes a functional protein expressed based on the needs of the cell
central dogma
dna
mrna
protein
dna: mrna - transcription
mrna: protein - translation
gene expression
the use of gene information to make mRNA and protein
specific sequence of nucleotides in DNA can be copied to
make another DNA
make mRNA that is directed to protein synthesis
flow of genetic info
expression
recombination
replication
expression
transcription occurs from parent DNA
mRNA for gene synthesized by RNA polymerase
goes to ribosome: translated to protein
recombination
exogenous genetic info gains entry into the cell and incorporates with host DNA: recombination of genes
replication
makes daughter cell from parent cell
genotype
what encodes phenotype
phenotype
physical trait
dna replication
initiation
elongation
termination
initiation
the unwinding of the helix, priming and loading of DNA polymerase enzyme complex
elongation
sequential extension of DNA by adding DNA nucleotide triphosphates (dNTPs) with the release of pyrophosphate
termination
DNA helix is completely duplicated and replication stops
DNA polymerase 1
removes RNA primer and replaces it with newly synthesized DNA
DNA polymerase 3
main enzymes that adds nucleotides in the 5-3 direction
helicase
unwinds DNA helix by breaking hydrogen bonds
ligase
seals gaps between Okazaki fragments especially in lagging strand
single stranded binding proteins
binds to single-stranded DNA to prevent hydrogen bonds from reforming double-stranded DNA
topoisomerase
relaxes supercoiled DNA
DNA replication/transcription occurs where
prokaryotes: cytoplasm
eukaryotes: nucleus
translation occurs where
cytoplasm for both
RNA transcription
RNA polymerase: DNA to mRNA
just a portion of the DNA that has the gene that encodes for a protein needed at the time is transcribed
1 mRNA in prokaryotes
multiple proteins
polycistronic mRNA
upstream
before initiation
downstream
after initiation
promoter
transcription starts at TATA box
-10 to -35 nucleotides upstream of start codon
translation
mRNA made into amino acids
genetic code
mRNA codon and amino acid
translation starts at
AUG
translation ends at
UAA
UGA
UAG
transfer RNA tRNA
exist in cytoplasm
bind to codon on mRNA and add specific amino acid to polypeptide chain
initiation translation
translational complex forms
tRNA brings first amino acid to polypeptide chain to bind to start codon
termination translation
release factor recognizes stop codon
translational complex disassociates
elongation translation
tRNAs bring amino acids one by one to add to the polypeptide chain
signal peptide
enhance movement of protein to another part of the cell
point mutation/ base substitution
single nucleotide is changed in a DNA sequence
3 types of point mutation
silent: no effect on protein
missense: different amino acid
nonsense: stop codon
insertion/deletion mutation
addition or subtraction of one or more nucleotides can form frameshift mutation: different protein
inversion
fragment of DNA is flipped in orientation in relation to the DNA on the other side
physical agents of mutations
cosmic rays
x rays
UV radiation: can be used to sterilize equipment
chemical agents of mutations
reactive oxygen molecules
superoxide radicals
acridine orange
certain biological processes
targeting DNA w an X ray
can break DNA strand
when breakage anything can fill the gap
non ionizing ray
UV light can cause a kink
DNA bends: causes some base pairs to interact
types of DNA repair
base excision repair
Methyl mismatch repair
SOS
DNA recombination
levels of gene regulation
changing the DNA sequence
Control of transcription
Translational control
Post translational control
changing DNA sequence
some microbes change the DNA sequence to activate or disable a particular gene
control of transcription
transcription can be regulated by protein repressors, activators, and alternative sigma factors
translational control
cell decides whether or not to make a protein
post translational control
control of proteins that are already made
activate or deactivate or degrade protein
