B1.2.2 Transcription And Translation

Question 1

How is a copy of DNA made? (3)

Answer 1

DNA can’t leave the nucleus of a cell since its too big.
Instead a copy of it is made called messenger RNA
This is like a single strand.

Question 2

In which process is mRNA produced?

Answer 2

Transcription

Question 3

Define transcription? (3)

Answer 3

-DNA unzips
-Free RNA bases pair in complementary pairs to make mRNA.
-mRNA detaches from the DNA and leaves the nucleus where it travels to a ribosome.

Question 4

Define translation first part (3)

Answer 4

-mRNA attaches to a ribosome.
-The mRNA bases are read in codons.
-carrier molecules also known as tRNA bring specific amino acids

Question 5

Name three differences between DNA and mRNA

Answer 5

DNA has deoxyribose sugars whereas mRNA has ribose sugars
DNA nucleobases are AGCT whereas in mRNA they are ACGU
DNA is double stranded and mRNA is single stranded
one is formed in DNA replication and the other is formed during transcription

Question 6

What happens when the gene is switched on? (3)

Answer 6

An enzyme called RNA polymerase attaches to the start of the gene. Moves along the DNA, making a strand of messenger RNA out of free bases in the nucleus.

Question 7

What are the two steps to protein synthesis?

Answer 7

• Transcription
• Translation

Question 8

Name two differences between transcription and translation

Answer 8

Transcription- Uses a strand of DNA to build a molecule of mRNA
Translation- Uses mRNA to build an amino acid chain
Transcription- occurs in nucleus
Translation- occurs in cytoplasm/ ribosome

Question 9

Define translation last part (3)

Answer 9

-Each codon codes for a specific amino acid.
-Continues reading, adding more and more amino acids
-Which form an amino acid chain which is a protein that is then released