Using the family tree below, answer the questions on your worksheet Starter: Using the family tree below, answer the questions on your worksheet

Task Put the following in size order, smallest to largest: Chromosome DNA Gene Nucleus

B1.7.1b Genes and Genetics Sort the parts of the cell into order of size (E) Describe how characteristics are inherited (C) Compare inherited and environmental variation (B) Characteristic Allele Gene DNA Chromosome Gametes Nucleus Variation

B1.7.1b Genes and Genetics Sort the parts of the cell into order of size (E) Describe how characteristics are inherited (C) Compare inherited and environmental variation (B) Characteristic Allele Gene DNA Chromosome Gametes Nucleus Variation

Chromosomes Found in the nucleus of cells. Chromosomes are formed from DNA molecules. The nucleus of most human cells contains 23 different sorts of chromosomes. There are usually two copies of each chromosome.

Genes Genes store information as a type of code – the genetic code. The genetic code organises amino acids to make specific proteins e.g. enzymes, hormones.

The DNA code A DNA molecule is made of two strands joined together by compounds called bases. The two strands are twisted around to form a double helix. There are 4 different bases A, T, C and G in a molecule of DNA. A gene is a sequence of bases along a strand of DNA.

The triplet code Proteins are made up of amino acids linked together in a chain. Different proteins contain different sequences of amino acids. A set of three bases in a DNA strand carries the code for one amino acid.

Inherited variation – differences between living things that are caused by genes.

Environmental variation – features that depend on our surroundings or on things that happen to us

Inherited, environmental or both? List as many characteristics of humans as you can and put them in the correct part of the Venn diagram. Inherited Both Environmental