DNA Structure 4.6.1.5

Question 1

What is the structure of DNA?

Answer 1

• DNA is a polymer made up of repeating units called nucleotides
• Each nucleotide consists of a common sugar and phosphate group and one of four bases attached to the sugar

Question 2

What are the four bases and what do they bind with?

Answer 2

• The bases are A,T,C and G
• A binds with T (A=T)
• C binds with G (C=G)

Question 3

How do bases code for amino acid?

Answer 3

• A sequence of 3 bases code for a particular amino acid

- The order of the bases controls the order the amino acids are assembled to produce a particular protein

Question 4

Describe the process of protein synthesis

Answer 4

• mRNA carries a copy of the code out of the nucleus into the cytoplasm to a ribosome
• tRNA brings the correct amino acids to add to the chain depending on the sequence of 3 bases reed by the ribosome.
• when complete the protein folds up into a unique shape to enable it to do its jobs

Question 5

What are types of mutation and ‘junk’ DNA?

Answer 5

• Not all parts of DNA code for proteins.

- Non-coding parts of DNA can switch genes on and off, so variation in these areas of DNA affect how genes are expressed