Unit 1.3 DNA

Question 1

DNA

Answer 1

Responsible for inheritance and for controlling cells by organising protein synthesis.

Chromosomes and plasmids are made of DNA. It is found in the nucleus.

Question 2

DNA structure

Answer 2

A double stranded molecule twisted into a helix (spiral).

It carries genetic information in its sequence of bases.

Question 3

DNA bases

Answer 3

Make up the central part of the DNA molecule.

They are arranged in complementary (matching) pairs : A-T and C-G

They carry genetic information as a genetic code.

Question 4

Genetic code

Answer 4

The sequence of bases in the part of a DNA molecule which is known as a gene.

Question 5

Gene

Answer 5

A section of DNA which codes for a protein by determining its amino acid sequence.

eg. the insulin gene contains the instructions for building insulin.

Question 6

Protein

Answer 6

A large molecule made of individual amino acids, which are joined together with chemical bonds to form a chain, which is then folded.

Question 7

Amino acids

Answer 7

The building blocks of proteins.

There are 20 different types of amino acid, which combine to produce a huge variety of proteins.

The amino acid sequence determines how a protein folds, so must be correct every time.

Question 8

Codon

Answer 8

A block of 3 bases on mRNA which codes for a specific amino acid.

Question 9

mRNA

Answer 9

A messenger molecule, made by copying the base sequence of a gene.

It carries a complementary copy of the genetic code from the nucleus to the cytoplasm, where it joins onto a ribosome.

Question 10

Ribosome

Answer 10

A structure found in the cytoplasm, which translates the code carried by the mRNA into an amino acid sequence in a protein.