Proteins and Mutations Part 1

Learning Objectives Learn about different types of proteins. Learn about the functions of different proteins. Understand what mutations are. Learn why some proteins are not made by all the cells in the body.

Starter What do all of these animals have in common?? They’re MUTANTS! Use your knowledge of DNA to explain the colours of the budgie and tiger.

Proteins We learnt last lesson that DNA codes for proteins. You need to know the names and functions of a few proteins in particular. Use page 14 of the student book to find out the function of collagen, insulin & haemoglobin and complete worksheet 1 Stick the sheet in your book.

Collagen Collagen is a structural protein. It is found in artery walls. It is also found in skin, bone and even teeth.

Insulin Insulin controls blood glucose levels. It belongs to s group of proteins called hormones. It is produced in the pancreas. Not all cells produce insulin! Only the cells of the pancreas. Do plant cells make insulin?

Haemoglobin Haemoglobin is only found in red blood cells. It is the reason red blood cells carry oxygen. Remember, only red blood cells need haemoglobin, so brain or liver cells wouldn’t make it.

Mutations The DNA of an organism codes for it’s features and characteristics. But what if something went wrong with the code? not likely! it happens! - Having a sixth finger is called polydactyly. Caused by a mutation.

Mutations Gene mutations or spontaneously (randomly). The chance of a mutation happening can increase due to: – RADIATION – CHEMICALS (such as tar in cigarettes). Mutated genes normally code for a different shaped protein. The new protein may be harmful and even cause death (cancer). Sometimes a mutation can be beneficial (evolution). Sometimes a mutation can be neutral (blue budgies).

Examples of Mutations Haemophilia Haemophilia is caused by a mutated gene. The blood of a person with this condition does not clot because a clotting protein is not produced. It is dangerous because bleeding does not stop. Sickle Cell Anaemia In this condition, the shape of the red blood cells is different. This stops them carrying oxygen efficiently. However, people with sickle cell anaemia cannot get malaria.

Task In groups, discuss if you think the following mutations would benefit or harm a species: Albino rabbits – The gene that gives skin colour mutates; the result is a white rabbit. Cystic fibrosis – A gene for an important protein is changed; the result is a human with breathing problems. Dark moths – A type of moth that is normally peppered in colour becomes dark; the result is better camouflage on dark-coloured trees but they show up on most light-coloured trees. During the industrial revolution, many trees were dark due to pollution; now most trees are light in colour. Resistant bacteria – Some bacteria have mutated to become resistant to antibiotics. Sickle cell anaemia – A mutation that makes people ill but stops them catching a fatal disease called malaria.

Task Using what you have learnt over the last few lessons, create a poster, or information leaflet on DNA and Proteins. You may include ideas on the following: DNA Structure Genes & Genetic Code Base Sequences Protein Synthesis Proteins & Mutations Use your notes and pages to help you create your poster or leaflet.

HIGHER

Protein Shapes Proteins are made of amino acids. The number and sequence of amino acids in a protein is important, and is known as the protein’s primary structure. Mutations cause the primary structure of a protein to fold into the incorrect shape. The protein can then no longer carry out its function properly. Final shape

Switched On or Off Every cell in your body has the exact same DNA. But cells in different parts of your body look different and don’t make the same types of protein. This is because cells only ‘switch on’ the genes they need! A pancreas cell produces insulin, so switched on the insulin gene. A cell in your kidney does not need insulin, so the insulin gene is switched off.

Task Answer questions 7-9 on page 15 of the student textbook. ANSWERS: 7. Because it codes for the order of amino acids in a protein and therefore the primary structure of a protein. 8. Because the gene fore insulin aren’t switched on. 9. An incorrect primary structure, which then didn’t fold into the correctly shaped protein (haemoglobin).

Learning Objectives Learn about different types of proteins. Learn about the functions of different proteins. Understand what mutations are. Learn why some proteins are not made by all the cells in the body.