Biology

1. Biology DNA, RNA, Proteins & Genetic Engineering

2. DNA Learning Intentions • What is DNA? • What does DNA code for? • How does mRNA help make proteins? • Give examples of proteins

3. 1. What is DNA? Chromosomes are divided up into packets of information called genes Genes are made up from DNA & they code for making proteins DNA is made up 4 bases – A, T, G, C How many chromosomes should humans have in each body cell?

4. 2. What is DNA? DNA is a double stranded helix. DNA is made up of complementary DNA bases The DNA bases are A, T, G, C A pairs with T & G pairs with C The order (sequence) of the bases on DNA are very important! What is DNA? (2:44)

5. 3. DNA code DNA carries the genetic code for making really important proteins. The DNA sequence of bases codes for the order of AMINO ACIDS Amino acids join together to make a protein The sequence of AMINO ACIDS determines which type of PROTEIN gets made DNA Fact File (1:24)

6. 4. What is mRNA? DNA contains the genetic code to make proteins mRNA copies the code from DNA in the nucleus mRNA carries the code out of the nucleus, through the cytoplasm to a ribosome

7. 5. How do proteins get made? DNA has the code for the protein (e.g. salivary amylase) • mRNA copies the DNA code inside the nucleus 2. mRNA carries the code from the nucleus to a ribosome 3. At a ribosome, amino acids are placed in the order relating to the code • Amino acids join together to make a protein How proteins are made? (2:55) Build a Play-doh model

8. 6.Where do Proteins get made? Nucleus (containing DNA code) • In nucleus, mRNA copies DNA code for making protein • mRNA moves out nucleus into cytoplasm and carries code to Ribosome • At a Ribosome, amino acids line up according to the code • The protein is made (assembled) at the Ribosome • The protein is released from the cell mRNA (copies the DNA code) Ribosomes (the site where proteins get made (assembled)

9. 7. Different types of proteins The order of the amino acids determines the shape and function of the protein produced. The structure of a protein is important for its function as proteins have a specific shape. Proteins can be:- structural (e.g. found in cell membrane) enzymes (e.g. salivary amylase) hormones (e.g. insulin) antibodies (e.g. to fight infection) Antibody image

10. 8a) Proteins & Genetic Engineering Genetic Engineering Genetic Engineering is when genes from one organism are inserted into another organism (e.g. genes from a human inserted into a bacterium) • The gene is identified (e.g. Human insulin) • The gene is extracted from the chromosome • The gene is inserted into a vector/bacterial plasmid • The plasmid is put into a host cell (e.g. bacteria) • Growth of transformed cells occurs, and desired gene product is produced (insulin) • Organisms which have had additional genes inserted into them are called Genetically Modified (GM) Organisms Insulin – video clip (2:29) Genetic Modification (2:49)

11. 8b - Genetic Engineering

12. 8c) Genetic Modifications The GloFish Zebrafish which have had genetic information from bioluminescent jellyfish added to its DNA. The Grapple A genetic cross between an apple and a grape. The grapple was originally designed to provide a much higher vitamin-c dose per fruit for third world aid. The majority of the funding for the fruit came from UNICEF

13. 8d) Genetic Modifications Poisonous Cabbage The gene that codes for poison in scorpion tails has been inserted into cabbage. These genetically modified cabbages produce scorpion poison that kills caterpillars when they bite leaves — but the toxin is modified so it isn’t harmful to humans. Thus preventing crops being destroyed by caterpillars. Less Cow Methane Cows release methane as a result of their digestion process. Methane is produced by a bacterium that feeds on the grass and hay in the stomach of the cow. Methane contributes to the greenhouse effect Scientists have identified the bacterium responsible for producing methane and have produced a strain of cattle that produces 25% less methane than the average cow.

14. 8e) Genetic Modifications Silk in Milk Strong, flexible spider silk is one of the most valuable materials in nature. It can be used to make lots of products (eg. artificial ligaments, parachute cords) The silk is hard to collect in large quantities. Researchers inserted a spiders’ dragline silk gene into the goats’ DNA in such a way that the goats would make the silk protein in their milk. This “silk milk” could then be used to manufacture a web-like material called Biosteel Large Salmon Genetically modified salmon grow twice as fast as the conventional variety — the photo shows two same-age salmon with the genetically altered one in the rear. Genetically engineered Atlantic salmon has an added growth hormone from a Chinook salmon that allows the fish to produce growth hormone year-round.

15. 8f) Genetic Modifications Glow Cats GLOW cats are used to help with AIDS research. The cats glow green under UV light because the green fluorescent protein (GFP) gene originating from jellyfish has been inserted in them. The GM cats also carry a monkey gene, which protects monkeys from infection by feline immunodeficiency virus or FIV – responsible for cat AIDS. Ear Mouse The Vacanti mouse was a laboratory mouse that had what looked like a human ear grown on its back. The "ear" was actually an ear-shaped cartilage structure grown by seeding cow cartilage cells into a biodegradable ear-shaped mold and then implanted under the skin of the mouse