3.4.2 DNA and protein synthesis Flashcards
What is the genome?
The genome is the complete set of genes in a cell.
What is the proteome?
The proteome is the full range of proteins that a cell is able to produce.
What is the structure of mRNA?
mRNA is a single polynucleotide strand with codons of three bases and does not form hydrogen bonds with itself.
What is the structure of tRNA?
tRNA is a single polynucleotide strand folded into a cloverleaf shape held by hydrogen bonds and has an anticodon and an amino acid binding site.
What is transcription?
Transcription is the production of mRNA from DNA.
What is the role of RNA polymerase in transcription?
RNA polymerase joins RNA nucleotides together to form a strand of mRNA.
What is produced from transcription in prokaryotes?
In prokaryotes transcription results directly in the production of mRNA from DNA.
What is produced from transcription in eukaryotes?
In eukaryotes transcription produces pre-mRNA from DNA.
What happens to pre-mRNA in eukaryotes?
Pre-mRNA is spliced to remove introns to form mRNA.
What is translation?
Translation is the production of polypeptides from the sequence of codons carried by mRNA.
What is the role of ribosomes in translation?
Ribosomes move along mRNA and facilitate the binding of tRNA anticodons to mRNA codons.
What is the role of tRNA in translation?
tRNA carries specific amino acids to the ribosome and has anticodons complementary to mRNA codons.
What is the role of ATP in translation?
ATP provides energy for the formation of peptide bonds between amino acids.
Transcription – Describe transcription (7)
- DNA strands separate by breaking hydrogen bonds;
- (Only) one of the strands is used as a template (to make mRNA);
- Complementary base pairing so A to U, T to A, C to G, G to C;
- (RNA) nucleotides joined by RNA polymerase;
- Forms phosphodiester bonds
- Pre-mRNA formed;
- Splicing/ introns removed to form mRNA
Translation – Describe translation (7)
- mRNA binds to ribosome;
- ribosome moves to start codon/AUG
- Idea of two codons/binding sites;
- (Allows) tRNA with anticodons to bind/associate with codon on mRNA;
- tRNA brings specific amino acid;
- mRNA moves along to the next codon;
- (Catalyses) formation of peptide bond between amino acids (held by tRNA molecules);
Translation – Role of ribosome (5)
- mRNA binds to ribosome;
- Idea of two codons/binding sites;
- (Allows) tRNA with anticodons to bind/associate;
- (Catalyses) formation of peptide bond between amino acids (held by tRNA molecules);
- Moves along (mRNA to the next codon)/translation described
Translation – Role of tRNA (4)
- anticodon complementary to codon/reads message on mRNA;
- specific amino acid;
- carried/transferred (to ribosome);
- correct sequence of amino acids along polypeptide;
Describe how a phosphodiester bond is formed
between two nucleotides within a DNA molecule.
- Condensation (reaction)/loss of water;
2 between phosphate and deoxyribose;
3 (catalysed by) DNA Polymerase
What is a gene
A sequence of DNA nucleotides that codes for a polypeptide;
The genome is…..
(The) complete set of genes in a cell. OR (All) the DNA in a cell/organism;
The proteome is…..
(The full) range/number of different proteins that a cell is able to produce (at a given time);
OR
(The full) range/number of different proteins the genome/DNA is able to code
Describe how one amino acid is added to a polypeptide that is being
formed at a ribosome during translation.
- tRNA brings specific amino acid (to ribosome);
- Anticodon (on tRNA) binds to codon (on mRNA);
- Amino acids join by condensation reaction (using ATP)
OR
Amino acids join to form a peptide bond (using ATP);
