B1 DNA And Protein Synthesis

Question 1

What is DNA made up of?

Answer 1

Nucleotides

Question 2

How many nucleotides are there in DNA?

Answer 2

Four

Question 3

What molecules form the backbone to the DNA strand?

Answer 3

One sugar molecule, one phosphate molecule.

They are the same in all DNA nucleotides.

Question 4

What joins to sugar molecule in a nucleotide?

Answer 4

A base

Question 5

List the four different bases found in a DNA molecule

Answer 5

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

Question 6

How does a base link on the opposite side of the helix?

Answer 6

To a base on the opposite side.

Question 7

What is complementary base pairing?

Answer 7

Adenine (A) pairs with thymine (T)

Cytosine (C) pairs with guanine (G)

Question 8

What is genetic code?

Answer 8

The order of bases in all of an organisms DNA (genome).

Question 9

What decides the order of amino acids in a protein?

Answer 9

The order of the bases in a gene.

Question 10

How are minor acids coded for?

Answer 10

By a sequence of three bases in the gene called a triplet.

Question 11

What does the triplet AGG code for?

Answer 11

Amino acid arginine.

Question 12

What does the sequence AGGCTT code for?

Answer 12

Arginine then leucine.

Question 13

What determines how amino acids are joined together to make various proteins?

Answer 13

The order of the bases in the gene.

Question 14

How are the properties of each protein determined?

Answer 14

By the particular amino acid sit contains and theories they’re present in.

Question 15

Where is DNA found?

Answer 15

In the cell nucleus.

Question 16

Why can’t DNA move out of the cell nucleus?

Answer 16

Because it’s really big.

Question 17

Where does the cell need to move information from the DNA to and why?

Answer 17

To the cell cytoplasm, so proteins can be synthesised.

Question 18

How is information moved from the DNA to the cytoplasm?

Answer 18

Using a molecule called messenger RNA (mRNA)

Question 19

How does mRNA differ from DNA?

Answer 19

It is shorter and only a single strand.

It uses uracil (U) instead of thymine (T) as a base.(U still pairs with A)

Question 20

How is DNA the same as mRNA?

Answer 20

Both polymers of nucleotides.

Question 21

Describe how proteins are made (5)

Answer 21

In the nucleus, the two strands of DNA unzip.
The DNA is used as a template to make mRNA (base pairing ensures the mRNA is complementary to the opposite DNA strand)
The mRNA molecule moves out of the nucleus and into the cytoplasm, where it attaches to a ribosome.
Amino acids are then joined together in the correct order by the ribosomes, following the order of the triplets in the mRNA.
This makes the protein coded for by the gene.

Question 22

Explain how a gene codes for a protein (2 marks)

Answer 22

Each triplet of bases in a gene codes for an amino acid (1 mark)

The order of the triplets in a gene determines the order of amino acids in a protein (1 mark)