Protein Synthesis

Question 1

What are the two differences between DNA and RNA?

Answer 1

• DNA has deoxyribose; RNA has ribose
• DNA has thymine; RNA has uracil

Question 2

Name the enzymes involved in transcription.

Answer 2

DNA helicase + RNA polymerase

Question 3

Why is the antisense strand needed even though it does not code for proteins?

Answer 3

• it acts as the template strand
• to form the complementary mRNA with the same base sequence as the sense strand

Question 4

What type of bond does mRNA have?

Answer 4

phosphodiester bonds

Question 5

Even though DNA codes for proteins directly, why is mRNA needed to be made for making proteins?

Answer 5

DNA is too large to leave the nucleus through the nuclear pores

Question 6

How is rRNA involved in catalysing translation?

Answer 6

• peptidyl transferase is an rRNA component
• it transfers one amino acid to another

Question 7

Which part of tRNA binds to the mRNA?

Answer 7

anticodon loop

Question 8

Name the amino acid that is always at the start of a protein.

Answer 8

Methionine

Question 9

Describe what happens to the amino acid chain to make it a fully functional protein.

Answer 9

• The amino acid chain folds into secondary and tertiary structures
• May undergo further modifications at Golgi

Question 10

State the two stages of protein synthesis.

Answer 10

Transcription + Translation

Question 11

Name the product of transcription.

Answer 11

mRNA

Question 12

Name the product of translation.

Answer 12

Polypeptide (then becomes functional protein after modification in Golgi)

Question 13

State the location where translation occurs.

Answer 13

Ribosomes