The Genetic Code

Question 1

According to the “Central Dogma”

Answer 1

• DNA needs to be translated into protein somehow
• Concern is that DNA is stuck in the nucleus

Question 2

Solution to the “Central Dogma”

Answer 2

The message on DNA is copied first onto another molecule

Question 3

Transcription

Answer 3

Process by which the codon base sequence on DNA is copied onto an mRNA molecule so that the code can be carried out into the cytoplasm

Question 4

What is a codon?

Answer 4

• A sequence of 3 base pairs
• Codes for one amino acid

Question 5

Translation

Answer 5

• Process by which codons on mRNA are converted into amino acids
• Eventually join together to make a protein

Question 6

How many combinations of codons are there?

Answer 6

64

Question 7

Why was the code said to be “Redundant” or “Degenerate”

Answer 7

Because there are 20 amino acids so several codons code for the same amino acid

Question 8

Why is the code no longer called “Redundant” or “Degenerate”

Answer 8

Because this avoids issues when some types of substitution mutations occur

Question 9

mRNA=

Answer 9

Messenger RNA

Question 10

What is mRNA?

Answer 10

• Product of DNA transcription and is complementary to the DNA template
• Goes into the cytoplasm
• Binds to a ribosome

Question 11

tRNA=

Answer 11

Transfer RNA

Question 12

What is tRNA?

Answer 12

• Brings in amino acids to ribosomes according to the mRNA codons
• Folded up version of RNA

Question 13

Parts of tRNA

Answer 13

• amino acid acceptor site
• mRNA binding site

Question 14

What is an anticodon?

Answer 14

It is complementary to mRNA codes

Question 15

rRNA=

Answer 15

Ribosomal RNA

Question 16

What is rRNA?

Answer 16

• A two-part molecule that makes up ribosomes

Question 17

What are the two parts of a ribosome?

Answer 17

• Heavy Subunit
• Light Subunit

Question 18

RNA polymerase I

Answer 18

• Makes rRNA
• Made in nucleolus and shipped out

Question 19

RNA Polymerase II

Answer 19

• Makes mRNA
• Made in nucleus and shipped out

Question 20

RNA Polymerase III

Answer 20

• Makes tRNA
• Made in nucleus and shipped out

Question 21

Prokaryotes…

Answer 21

• Have no nuclei
• DNA is not separate from ribosomes
• Transcription and translation occur quickly

Question 22

Where does transcription occur in eukaryotes

Answer 22

• In the nucleus and mRNA must be modified before leaving it

Question 23

Where does translation occur in eukaryotes?

Answer 23

• In the cytoplasm
• At the ribosomes