3.4.2 DNA and protein synthesis Flashcards
1
Q
what is the genome?
A
the complete set of genes in a cell
2
Q
what is a proteome?
A
the full range of proteins that a cell is able to produce
3
Q
what are the 3 types of RNA?
A
- ribosomal RNA
- messenger RNA
- transfer RNA
4
Q
describe the structure of ribosomal RNA
A
with proteins they make up ribosomes
5
Q
describe the structure of messenger RNA
A
- single stranded helical polynucelotide strand
- made in the nucleus
- carries the genetic code into the cytoplasm
- chemically unstable = broken down within days
6
Q
describe the structure of transfer RNA
A
- smallest single polynucleotide strand folded into a clover leaf shape
- hydrogen bonds hold it in shape
- made in the nucleus
- has amino acid binding site - binds amino acid and carries it to ribosome
- more stable than mRNA
7
Q
what are 3 bases in mRNA called?
A
codon
8
Q
what are 3 bases of tRNA called?
A
anti-codon
9
Q
outline transcription
A
- RNA polymerase binds to promoter region, breaks hydrogen bonds between bases
- one strand of DNA acts as a template, forms complementary base pairs with free RNA nucleotides
- A pairs with U instead of T
- RNA polymerase joins adjacent nucleotides together by condensation reactions to form phosphodiester bonds
- this produces pre-mRNA
- DNA strands rejoin to form double helix
- RNA polymerase reaches terminator region and detaches
10
Q
what is transcription?
A
the process of copying the genetic code to form mRNA
11
Q
why does splicing of pre mRNA happen?
A
- in eukaryotes introns are removed
- in prokaryotic dna splicing doesnt happen since they aren’t any introns
12
Q
outline translation
A
- mRNA attaches to ribosomes at the start of the codon
- a tRNA molecule with a complementary anti-codon moves to the ribosome pairing with the mRNA codon by complementary base pairing
- tRNA carries a specific amino acid
- a 2nd tRNA attaches itself to the next codon
- the 2 amino acids are joined by peptide bonds which releases the first tRNA back into the cytoplasm
- the energy to form the bond comes from the hydrolysis of ATP
- the chain folds as it is produced
- at the stop codon, the polypeptide chain is complete and moves away from ribosome
13
Q
what is translation?
A
the process of using the genetic code on mRNA to assemble the amino acids of a polypeptide chain in the correct order
