DNA and protein synthesis Flashcards
1
Q
What is a genome?
A
The complete set of genes in a cell (all of the cells DNA)
2
Q
What is a proteome?
A
The full range of proteins that a cell is able to produce
3
Q
What is the structure of mRNA?
A
- single-stranded
- variable length (length of gene)
- linear shape
- no binding site for amino acids
4
Q
What is the structure of tRNA?
A
- single-stranded
- around 80 nucleotides long
- base pairing
- clover shape
- binding site for amino acids
- 3 bases forming the anticodon
5
Q
What is the structure of rRNA?
A
- part of the structure of a ribosome
6
Q
What is transcription?
A
- During transcription, hydrogen bonds between complementary base pairs break in the DNA by DNA helicase, and the antisense strand of DNA is used as a template.
- Free RNA nucleotides bind to complementary exposed bases on the antisense strand, and nucleotides join by RNA polymerase forming phosphodiester bonds, to form pre-mRNA
- In eukaryotic cells, the pre-mRNA is spliced meaning the introns are removed which forms mature mRNA which can leave the nucleus through pores to travel to the ribosomes
7
Q
What is translation?
A
- During translation, the mRNA attaches to a ribosome.
- The codon on mRNA will bind to an anticodon on tRNA, which carries a specific amino acid. tRNA will line up along the mRNA to form a specific sequence of amino acids (determined by the sequence of codons)
- Between each amino acid, energy from ATP hydrolysis is used to form a peptide bond in condensation reactions
- Once a peptide bond has formed, the tRNA molecule will leave and the ribosomes will move along the mRNA to continue the sequence
- Once the amino acid sequence is complete, tRNA will bring a stop codon which will end the chain of amino acids, to form a complete polypeptide