Cell structure and function: Genes to proteins

Question 1

Steps of Gene to protein

Answer 1

Transcription
processing
translation

Question 2

transcription and translation steps

Answer 2

intiation (polymerase bind to promoter)
elongation (move downstream and translate/scribe)
termination (detachment of polymerase)

Question 3

Transcription

Answer 3

1. eukaryotic promoter
2. several transcription factors bind to DNA
3. transcription initiation complex forms

Question 4

Strands

Answer 4

Template/non-coding: 5’ to 3’
non template/coding: 3’ to 5’

Question 5

elongation

Answer 5

DNA unwinds slightly (10-12 nucleotides)
complementary RNA nucleotides added to 3’ end of transcript (3’OH of transcript binds with 5’ phosphate of incoming nucleotide)
helix reforms as transcript leaves

Question 6

termination

Answer 6

nuclear enzymes release pre-mRNA and polymerase dissociates from the DNA

Question 7

Processing

Answer 7

capping: mod. guanine added to 5’ end
tailing: 50-250 adenine nucleotides added to 3’ end
splicing: introns spliced out and exons spliced together (spliceosome in nucleus)

Question 8

UTR

Answer 8

untranslated regions at 5’ and 3’ ends, important for stability

Question 9

Translation

Answer 9

codons translated into amino acids
hydrogen bonds form between mRNA and anticodon of tRNA
peptide bonds where amino acids are added to growing polypeptide chan

Question 10

EPA

Answer 10

A site: entry for tRNA carrying amino acid
P site: polypeptide chain forming
E site: tRNA exits

Question 11

Translation intitiation

Answer 11

tRNA carrying methionine binds to mRNA before large subunit arrives

Question 12

Termini

Answer 12

N terminus - from 5’ end of of RNA
C - terminus - from 3’ end of RNA

Question 13

Translation location

Answer 13

begins in free ribosomes in cytosol but the end proteins that don’t perform their function in cytosol go to RER and then golgi based on signal peptide at n terminus during translation