A The Same and Different what makes us different what genes are and what genes do.

The Same & Different New plants and animals look a lot like their parents. They have inherited information from them. This information controls how the new organisms develop. A lot of information goes into making a human being. So inheritance does a big job pretty well. All people have most features in common. Children look a lot like their parents. If you look at the people around you, the differences between us are very, very small but were interested in them because they make us unique.

These sisters have some features in common. The Same & Different These sisters have some features in common. “Aly & AJ”

Environment makes a difference Almost all of your features are affected by the information you inherited from your parents. For example your eye colour depends on this information. But most of your features are also affected by the environment. For example, your skin colour depends on inherited information. But if you spend time in the sun your skin will get darker.

Questions Choose two students in the photograph. Write down five ways in which they look different. What two things can affect how you develop? Explain what is meant by inherited information.

Inheritance – the story of life One important part of this story is where all the information is kept. Living organisms are made up of cells. If you look at a cell under a microscope you can see the nucleus. Inside the nucleus are long threads called chromosomes. Each chromosome contains thousands of genes. It is the genes that control how you develop. All the information needed to create a human being fits into the nucleus of a cell which is only 0.006mm across. nucleus nucleus genes genes genes genes genes genes chromosomes chromosomes chromosomes chromosomes chromosomes chromosome

What are chromosomes made of? Chromosomes are made of a chemical called DNA (Deoxyribonucleic Acid). Most kind of living things use DNA to make their chromosomes.

How do genes control your development? A fertilized egg cell has the instructions for making every protein in a human being. That’s what genes are – instructions for making proteins. Each gene is the instruction for making a different protein. Enzymes to speed up chemical reactions in the body. to move muscles. to build cells. PROTEINS to send chemical messages around the body. to fight bacteria & disease. to carry oxygen in the blood.

What’s so important about proteins? Proteins are important chemicals for cells. There are many different proteins in the body, each one does a different job. They may be; Structural Proteins – to build the body. Enzymes – to speed up chemical reactions in cells. Genes control the proteins a cell makes. This is how they control what the cell does..

Questions Write down these cell parts in order, starting with the smallest. Chromosome, gene, cell, nucleus Explain how genes control what a cell does. List two kinds of job that proteins do in the human body. Name two proteins in the human body and say what they do.

Key Words Nucleus – the part of the cell which contains genetic information (chromosomes). Chromosome – Long, thin, thread-like structures found in the nucleus of a cell made from a molecule of DNA. Chromosomes carry the genes. Structural – proteins which are used to build cells. DNA – Deoxyribonucleic Acid, the chemical that makes up chromosomes. DNA carries genetic doe. Protein – Chemicals in living things that are polymers made by joining together amino acids. Genes – A section of DNA giving the instructions for a cell about how to make one kind of protein. Enzymes – A protein that catalyzes chemical reactions in living things.