8. DNA, genes and protein synthesis Flashcards
(51 cards)
what two things do genes code for the production of?
amino acid sequence of a peptide
functional RNA
what is meant by the term ‘degenerate code’
several codons code for the same amino acid
what are the non-coding sections of DNA called?
introns
Name the 4 different bases in DNA, and their complementary pairings
Guanine cytosine adenine thymine G-C A-T
Which base is switched to uracil in RNA
Thymine
define genome
the complete set of genes in a cell
define proteome
the full range of proteins a cell is able to produce
define allele
an alternative form of gene
two sister chromatids are joined by what?
centromere
the section of three bases in tRNA which binds to the mRNA strand is called…
anticodon
give the three components of DNA?
deoxyribose, pentose (5) carbon sugar
phosphate backbone
nitrogenous base
What is the difference between the components of RNA and the components of DNA?
RNA contains ribose opposed to deoxyribose
in what process is pre-mRNA created?
transcription
which enzyme is involved in transcription to join RNA nucleotides together?
RNA polymerase
what is the DNA strand known as in transcription?
template strand
what happens to pre-mRNA before it leaves the nuclear envelope?
the introns are removed
when mRNA is in the cytoplasm, which organelle does it attach to for the next stage of protein synthesis?
ribosome
what bond forms between two amino acids in protein synthesis?
peptide bond
what is the role of ATP in translation?
provides energy for bond to form between tRNA and the amino acid
what is the role of tRNA in translation?
carries amino acids to the nucleotide. lines them up in the correct order.
define translation
the process of converting the codon sequence in the mRNA molecule into an amino acid sequence
explain the process of translation.
The mRNA molecule passes out of the nuclear pore after splicing.
A ribosome attaches to the start codon of the mRNA
A tRNA with the complementary anticodon sequence to the first mRNA codon pairs with the codon on the mRNA
The ribosome has two codon binding sites, so two tRNA molecules at a time are brought together
A peptide bond forms between the 2 amino acids on the tRNAs with the use of an enzyme and ATP which is hydrolysed to provide energy
The ribosome moves along the mRNA to the next codon so the first tRNA is released and a new tRNA arrives at the next codon
This continues, with up to 15 amino acids being added each second until a polypeptide chain is built up
what is the term used when talking about a section of a gene in a eukaryote?
allele
what is meant by the term diploid number?
the number of chromomsomes