protein synthesis

Question 1

compare structural and regulatory genes

Answer 1

• structural genes code for proteins that become part of the structure or function of a cell
• regulatory genes code for proteins that control the expression of other genes

Question 2

define gene regulation, purpose, process, why it needs to occur

Answer 2

purpose: to conserve energy, by expressing only the genes that are required an organism will conserve its energy
process: turning genes on and off
why:
- needs to occur in order for a cell to produce proteins that aren’t available in the cell or prevent a cell from creating proteins bc the protein is already in the cell

Question 3

define operon, transcribed as.., fact

Answer 3

• related genes found in a cluster on a chromosome, all under the control of one promoter
• operon is transcribed as a single entity creating 1 long strand of mRNA
• transcription and translation happen simultaneously so that more than 1 protein can be made in a shorter amount of time (fast)

Question 4

translation in eukaryotic genes

Answer 4

• mRNA leaves the nucleus and goes into a ribosome 5’ end first where it is read as codons.
• translation begins at the “start adding amino acids” signal
• amino acids which are unambiguous, degenerate and universal are then brought to the ribosome by tRNA.
  -> at 1 end of the tRNA molecule there are 3 bases making an anti-codon while the other end is a region that attached to a specific amino acid.
• as the ribosome reads the mRNA tRNA molecules will deliver the appropriate amino acids to the ribosome and as they’re added peptide bonds will form creating a polypeptide chain.
• once the ribosome reaches and reads the “stop” codon the polypeptide chain is released from the ribosome

Question 5

describe condensation polymerisation

Answer 5

• the process of joining 2 amino acids together using energy and then water is released.
• carboxyl group of one amino acid binds with amino group of another

Question 6

transcription in eukaryotes

Answer 6

• RNA polymerase assembles at the promoter region with other transcription factors.
• RNA polymerase will then run along the dna strand starting at the 5’ end transcribing the exons, introns and 3’ end of the template strand of dna as it unwinds the dna creating pre-mRNA
• the pre-mRNA will then leave the dna

Question 7

RNA processing

Answer 7

methyl cap is added to 5’ end poly-A tail is added to 3’ end, introns are removed and exons are spliced together creating mRNA

Question 8

repression in the trp operon

Answer 8

• occurs when when levels of trp are high in the cell
• prevents the process of transcription from the beginning

1. when trp is present in a cell it will bind to a repressor protein and activate it
2. the activated repressor will bind to the operator region of the operon, preventing RNA polymerase from transcribing any of the genes

Question 9

attenuation in trp operon

Answer 9

Prevents transcription from finishing
-> by producing a terminator region

When trp is present in the cell
1. Transcription and translation of mRNA will both occur quickly as the required trp molecules are present
2. this causes the mRNA to fold into a terminator region, stopping RNA polymerase from transcribing.

when trp levels are low in the cell
1. transcription and translation occur slowly
2. allows for an anti-terminator region to form
3. enabling the cell to finish transcription and translation and continue to make tryptophan

Question 10

DNA facts
1. runs…
2. prime end
3. codes for…
4. vital for…
5. DNA is…

Answer 10

1. runs anti-parallel
2. 5’ end is phosphate
3. 3’ end is the hydroxyl group of the pentose sugar
4. vital for the structure and function of an organism
5. DNA is universal