Biology unit 5

What is a codon?
A group of three bases that codes for one amino acid
1 of 24
What is meant by degenerate?
More than one codon for each amino acid
2 of 24
What is mRNA?
Carries the message that codes for a particular protein from the nucleus to the cytoplasm, contains one gene only.
3 of 24
what is tRNA?
Matches amino acids to their codon
4 of 24
what is rRNA?
rRNA with proteins forms ribosomes, the site of mRNA translation and protein synthesis.
5 of 24
What is the promoter?
A special sequence of bases that marks the start of each gene on DNA
6 of 24
What is the template strand?
The copied DNA strand (original strand)
7 of 24
How are the new nucleotides in transcription joined together?
By strong covalent phosphodiester bonds by the enzyme RNA polymerase
8 of 24
how long is an mRNA molecule?
the length of one gene
9 of 24
How does mRNA leave the nucleus?
Diffuses out through a nuclear pore into the cytoplasm and attaches to a ribosome for translation
10 of 24
what is post transcriptional modification?
the removal of introns from mRNA so it can translated into a protein
11 of 24
what is pre-mRNA?
intial mRNA that is transcribed, an exact copy of the gene on DNA (contains exons and introns)
12 of 24
what is splicing?
when introns are cut out and exons joined together, some is done by RNA itself or snurps
13 of 24
What is an initiation codon?
Nucleotides AUG on mRNA where ribosome attaches in translation, ribosome encloses two codons.
14 of 24
what is met-tRNA?
the first tRNA molecule with an amino acid attached that diffuses into the ribosome
15 of 24
what are ribozymes function?
To catalyse the cutting of the amino acid and tRNA bond and the formation of the peptide bond between amino acids
16 of 24
what is post-translational modification?
Modification of protein by enzymes, include chain cutting and addition of groups
17 of 24
How do mutations occur?
changes in bases during DNA replication
18 of 24
What is substitution mutation?
changing of one amino acid
19 of 24
what is a nonsense mutation?
Mutation leads to premature stop codon.
20 of 24
What are mutagens?
Chemicals that increase rate of mutation
21 of 24
What are proto-oncogenes role?
encode proteins that stimulate cell division, when activated by growth signals.
22 of 24
What is a oncogene?
Mutated proto, overly active making cell division unchecked.
23 of 24
What do mutated tumour supressor genes do?
stop making protein that inhibits cell division. mutation is recessive.
24 of 24

Other cards in this set

Card 2


What is meant by degenerate?


More than one codon for each amino acid

Card 3


What is mRNA?


Preview of the front of card 3

Card 4


what is tRNA?


Preview of the front of card 4

Card 5


what is rRNA?


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all DNA, genetics and evolution resources »