A large chemical molecule made of smaller chemical groups, it carries the genetic code of all living organisms.

A chemical made up of smaller repeating chemical groups.

A chemical substance whose structure is coded for by the genetic code in genes.

A small chemical group that makes up a protein polymer, there are 20 types.

A chemical group that make up the building blocks of DNA, the four types are coded A, T, C and G.

The genetic code

Biology

Pupils will learn about dominant and recessive alleles, and how to use models of single gene inheritance to make predictions about the genotypes and phenotypes of offspring.

Pupils learned about flower structure, wind and insect pollination, fertilisation, seed and fruit formation and dispersal.

This unit covers the structure and function of eukaryotic and prokaryotic cells, DNA as the genetic material, and key genetic terms. It also explains protein synthesis, genetic variants, and how DNA structure affects proteins. The emphasis is on using models to explain scientific concepts.

DNA and the genome

a polymer that carries the genetic code for all living organisms

small chemical group; 4 types (ATCG) are joined together to make DNA

long chain molecule made of small chemical groups joined together

a polymer that can be structural or functional, coded for by a gene

The diagram shows a nucleotide. DNA molecules have four types of nucleotides. 
Which sub units are the same in all four types?

Each nucleotide makes a different protein.

The number of nucleotides determines the protein.

Nucleotides on both DNA strands determine the protein.

Nucleotides on one DNA strand determines the protein.

A gene is a section of DNA that codes for a particular protein. Each gene is a sequence of nucleotides. There are four different nucleotides. 
Which statement best describes how this code works?

Each nucleotide codes for three amino acids.

Three nucleotides code for three proteins.

Three nucleotides code for one amino acid.

Three nucleotides code for three amino acids.

The genetic code is often described as a triplet code. Why?

Each three nucleotides make up a triplet code.

Each triplet code codes for one of 20 amino acids.

The triplet code sequence determines the amino acid sequence.

The amino acid sequence determines the structure of the protein.

Put the statements in order, to describe how the nucleotides in a gene are the code for making a protein.

A protein is 21 amino acids long. How many nucleotides code for this chain of 21 amino acids?

Starting with the largest, put the structures in order of decreasing size.

What does the order of nucleotide bases in a gene determine?

What is the name of the type of molecule that acts as a catalyst in living organisms?

The diagram shows a single nucleotide. Which part of the nucleotide joins the two strands of a DNA molecule together?

One strand of a DNA molecule has the base sequence **A A T C G A G C A**. 
Which is the complementary base sequence on the other strand of the DNA molecule?

The photograph shows a model of DNA made from jelly babies and liquorice sticks. 
In this model, which parts of the nucleotide molecules are represented by the liquorice sticks?

Starter Quiz