DNA to Protein

Question 1

You and your friend both have a chromosome 12. Do you have the same genes in the same location?

Answer 1

Yes

Question 2

What is the link between genotype and phenotype?

Answer 2

Proteins

Question 3

What are the two stages of gene expression and what happens here?

Answer 3

Two stages: transcription and translation. DNA directs protein synthesis.

Question 4

What is the central dogma of biology? (Illustrate)

Answer 4

DNA –(Transceiption)–> RNA –(Translation)–> Protein

Question 5

What is the difference between transcription and translation in prokaryotic vs eukaryotic cells?

Answer 5

In prokaryotic cells, transcription and translation happen in the same place at the same time; whereas in eukaryotic cells, transcription happens inside the nucleus and translation happens in cytoplasm.

Question 6

What are the stages of transcription?

Answer 6

Initiation, Elongation and Termination

Question 7

What are the steps in transcription?

Answer 7

RNA polymerase binds to promoter on template strand; reads 3’ to 5’, unwinding DNA; and dissociates when it reaches stop codon

Question 8

Where does RNA poly II bind to?

Answer 8

Template strand

Question 9

What happens in the elongation of the RNA strand?

Answer 9

As RNA polymerase moves along DNA, it untwists the double helix 10-20 bases at a time.

Question 10

True or False. Only one strand can be the template.

Answer 10

False! either strand can be the template

Question 11

What is the purpose of RNA splicing?

Answer 11

Splicing removes introns, joins exons, and creates mRNA with continuous coding sequence.

Question 12

How does splicing works?

Answer 12

Small RNAs recognize splice sites

Question 13

Why do we have introns?

Answer 13

They contain sequences that may regulate gene expression

Question 14

Define intron and exon.

Answer 14

Intron means interleaving sequence (in between sequence) and exon means expressed sequence.

Question 15

Whta is true about 5’ and 3’ UTRs?

Answer 15

They are part of the exon, transcribed but not translated.

Question 16

What shape does tRNA have and why is that?

Answer 16

Because of hydrogen bonds, tRNA molecules actually have 3D conformation, roughly L-shaped.

Question 17

What 2 steps does an accurate translation require?

Answer 17

Correct match between tRNA and amino acid, catalyzed by aminoacyl-tRNa synthetase; and correct match between tRNa anticodon and mRNA anticodon

Question 18

What is the function of eukaryotic ribosomes?

Answer 18

Facilitate coupling of tRNA anticodons with mRNA codons

Question 19

Whta are the three-binding sites for tRNA?

Answer 19

A site, P site and E site

Question 20

What happens in the initiation of translation?

Answer 20

Proteins called “initiation factors” bring in large subunit and this completes the translation initiation complex

Question 21

What happens in the elongation of translation?

Answer 21

Amino acids are added to preceding AA at the C-terminus of the growing chain

Question 22

What are the three steps in elongation of translation? (CPT)

Answer 22

Codon recognition, peptide bond formation, and translocation

Question 23

When does termination of translation occur?

Answer 23

It occurs when stop codon in mRNA reaches the A site

Question 24

What is the purpose of release factor?

Answer 24

It causes the addition of H2O instead of an AA

Question 25

What are polyribosomes means of?

Answer 25

Amplifying gene expression

Question 26

What is missense?

Answer 26

Changes in just one base pair of a gene