Dna And Protien Synthesis

Question 1

Define genome

Answer 1

Complete set of genes in a cell

Question 2

Define proteome

Answer 2

Full range of proteins a cell is able to produce

Question 3

What are the 3 features of dna

Answer 3

Universal- same triplet code used by all organisms
Degenerate- most amino acids are coded for by more then one triplet
Non overlapping- each base is only read once

Question 4

Describe the process of transcription

Answer 4

DNA helicase unzips dna, free nucleotides form complimentry base pairs with the nucleotides on ONE of the exposed dna strands
RNA polymerase joins rna nucleotides together using phosphodiester bonds to make mRNA
The mRNA produced is a copy of the sense strand of DNA
In mRNA uracil replaces thymine

Question 5

What does transfer rna do

Answer 5

Each carry an amino acid, the identity of the amino acid depends on the sequence of the anticodon

Question 6

What is an anticodon

Answer 6

Triplet of exposed bases that bind to codin of mRNA

Question 7

What are ribosomes made of

Answer 7

2 subunits that synthesise polypeptides
Made of rRNA and protein

Question 8

Describe the process of translation

Answer 8

mRNA binds to ribosome, tRNA molecule binds to each codon on mRNA, amino acid carried by tRNA is added to the polypeptide chain using peptide bonds between amino acids, continues until a stop codon is reached. The mRNA tRNA and ribosome seperate and the polypeptide chain is complete

Question 9

In eukaryotes what is produced after transcription

Answer 9

Pre mRNA
The introns are removed and the remaining exons are spliced together
Now it is ready to be translated

Question 10

Is splicing needed in prokaryotes

Answer 10

No

Question 11

What does splicing allow (post transcriptional modification)

Answer 11

Gives the same gene the opportunity to code for different proteins due to the order in which exons are combined

Question 12

What is post translational modification

Answer 12

Changes to the polypeptide. It is altered to become fully functional by enzymes
Includes chain cutting, adding methyl or phosphate groups to amino acids, adding sugars or lipids

Question 13

What is polysome

Answer 13

When a number of ribosomes work simultaneously on the same mRNA

Question 14

How is ATP used in the process of translation

Answer 14

Used to form peptide bonds between amino acids