CH 9 Flashcards
2 essential functions of the DNA
- genetic material for inheritance
- directs and regulates the construction of proteins
WHAT contains the full complement of DNA within a cell
genome
smaller discrete units of genomes
genes
genes are arranged where
chromosomes and plasmids
3 important processes
- Replication
- Transcription
- Translation
genotype vs phenotype
genotype: genes
phenotype: physical characteristics
DNA replication location in :
1. eukaryotes
2. prokaryotes
- nucleus
- nucleoid
4 phases of DNA Replication
- Unwinding
- Primer Bonding
- Elongation
- Termination
Enzymes included in DNA Replication
- Topoisomerase (unwind)
- Helicase (unzip)
- Primase (sets primer)
- DNA polymerase 3 (adds bases)
- Ligase (joins together Okazaki fragments)
- Exonuclease (removes primer
- DNA polymerase 1 (proofreads bases and adds where primer is removed)
Replication process that is unidirectional
Rolling Circle Replication
a specific genomic locus where DNA replication begins in Rolling Ciruclar Replciaton
ori
What enzyme binds to ori and what does it do and where does it bind
Rep-A - breaks a single strand called “NICK” and binds to 5’
Purines vs Pyramidines
Purines (adenine and guanine) are two-carbon nitrogen ring bases
Pyrimidines (cytosine and thymine) are one-carbon nitrogen ring bases
Direction of RNA initiation for start of transcription process
5’ -> 3’
kaya didikit si enzyme kay 3’ -> 5’ na dna strand
What short sections in the DNA signals when and where to start transcription process
Promoters
What binds to promoters to start transcription and how:
- eukaryotes
- prokaryotes
- Basal transcription factors bind first THEN RNA polymerase
- RNA Polymerase directly binds
What happens in ELONGATION process-transcription
RNA polymerase makes mRNA strand which is similar to non-template dna strand but uses URACIL
What happens in TERMINATION process-transcription
short DNA sequences “terminators” signal end of process
mRNA is released from polymerase
2 types of termination (transription) in BACTERIA
- Rho-independent (forms TERMINATING HAIRPINS and independent of external proteins)
- Rho-dependent (requires Rho Proteins which interacts with RNA polymerase)
What happens after transcription and process
RNA modifications
SPLICEOSOME removes introns (non-coding segments) and leaves exons
what do you call the sequence of three nucleotides that code for a specific amino acid
codons
How many possible codons are there
64 (61 coding + 3 stop codons)
what is the starting codon and the 3 stop codons
AUG (methionine)
UGA
UAA
UAG
What happens in initiation - translation
- Initiaion Factors 1 & 2 attach to small ribosomal unit
- tRNA with anticodon attaches to SRU
- Big ribosomal unit attaches to tRNA
What is the subunits of rRNA
Small subunit (30S in P; 40S in E)
Big subunit (50S in P: 60S in E)
What are the sites present in BIG SUBUNIT
E site (exit site
P site (polypeptide)
A site (Amino acid)
What happens in Elongation process - translation
AUG enters P site first and A site is for 2nd amino acid. The amino acids leaves thru the E site after forming peptide bonds
What happens in termination process - translation
stop codon enters A site
release factors breaks down sobrang peptide bonds at the end