Protien Synthesis

Question 1

Explain what coding DNA is

Answer 1

Part of a gene that codes for an mRNA codon that is read to make a specific amino acid.

Question 2

What is protein synthesis?

Answer 2

The process of producing proteins from instructions in coding sections of DNA, the proteins are joined by peptide bonds to form polypeptides

Question 3

What is transcription?

Answer 3

The synthesis of mRNA (messenger RNA) using coding DNA. The antisense strand is the one that is copied.

Question 4

What is the first step in transcription?

Answer 4

(Template strand is used)
- RNA polymerase binds to a promoter region after transcription starts
- RNA polymerase joins the complementary nucleotides
- DNA continues to unwind by the action of the RNA helicase

Question 5

What is the second step of transcription?

Answer 5

Moving in the 5’ 3’ direction, RNA ads nucleotides appropriatley (mRNA is added in 5’ to 3’ direction)

Question 6

What is the third step of transcription?

Answer 6

• DNA bases are read in triplets, and the complementary mRNA triplets are called codons
• Process continues until the pre-mRNA gets releases with termination signal

Question 7

What is the fourth step of transcription?

Answer 7

• Pre-mRNA consists of introns and exons, introns are removed (sections of non-coding DNA) and exons are joined to create mature mRNA
  -The mature mRNA exits the nucleus via nuclear pore

Question 8

What is tRNA?

Answer 8

(Transfer RNA) because its job is to bring the amino acid to the ribosome to build the protiens.

Question 9

Where does translation occur?

Answer 9

Ribosomes

Question 10

What is translation?

Answer 10

Synthesis of polypeptides using the info in mRNA. RNA nucleotide code is translated into an ammino acid sequence

Question 11

What is the first step of translation?

Answer 11

Initiation
- Ribosome binds to the mRNA strand

Question 12

What is the second step of translation?

Answer 12

Elongation
- The start codon (usually AUG) signals for the corresponding tRNA with the complementary anticodon to arrive

Question 13

What is the third step of translation?

Answer 13

Elongation (continues)
- Elongation process continues signalling for more tRNA according to the order of codons
- As each codon moves through the ribosome the ammino acid is added to a polypeptide chain and the tRNA is removed

Question 14

What is the fourth step of translation?

Answer 14

Termination
- When a stop signal is received elongation stops
- Chain of ammino acids is released from the ribosome
- Ribosome seperated from mRNA

Question 15

What occurs to the polypeptide chain after translation?

Answer 15

Folds to form a protein or joins with another polypeptide to fold and become a 3d protein ready to perform a function

Question 16

Which DNA strand is copied in transcription?

Answer 16

Antisense strand