3 B3a – Molecules of Life DNA Fingerprinting Controls movement in & out of cellChemical reactions take place here – e.g. enzymesSite of respiration (provides energy)Site of Protein SynthesisDNA FingerprintingComparing samples of DNA to help identify samples
4 B3b - Diffusion Lungs: Leaves: Placenta: Intestines: FOR EXAMPLE: The movement of a substance from a region of high concentration to a region of low concentrationFOR EXAMPLE:Lungs:Leaves:Placenta:Intestines:To INCREASE the rate of diffusion – have a LARGE surface area and GOOD blood supply
5 B3c - Keep it Moving The Heart 4 chambers – ventricles - atrium Plasma – yellow-ish fluid, carries glucose and CO2Red Blood Cells – carry the oxygenPlatelets – clot the bloodWhite Blood Cells – fight off infectionThe Heart4 chambers – ventricles - atriumToo much saturated fat and cholesterol – fatty deposits in blood vessels – coronary heart disease
6 B3d – Divide & Rule MITOSIS MEIOSIS To make gametes (egg and sperm) A diploid cell produces two diploid cellsFor growth, repair and replacementMEIOSISA diploid cell produces four haploid cellsTo make gametes (egg and sperm)FERTILISATIONWhen sperm joins with egg
7 B3e – Growing upA gestation period is the time spend developing in the womb in most animals.Growth involves (a) Cell Division – by MITOSIS (producing identical cells) and (b) Cell Differentiation.Cell differentiation involves producing different types of cells from undifferentiated cells called STEM CELLS
8 B3f – Controlling plant growth Plant hormones (also known as PLANT GROWTH REGULATORS or AUXINS) are chemicals that controlgrowth of ROOTS and SHOOTSLeaves are positively phototropic, towards lightLeaves are negatively geotrophic, away from gravityAUXINS are hormones which collect on the dark side of a shoot causing the cells to lengthenRoots are negatively phototropic, away from lightRoots are positively geototropic, towards gravity
9 B3g – New genes for old1 – select the characteristic you want to improve – larger eggs2 – cross breed the best hen with the best cockerel3 –select the offspring which produce the largest eggs and mate that with your best cockerel4. and repeat this over several generationsGENETIC ENGINEERINGIs when scientists transfer one gene from one living organism to another.The order of triplets in a gene determines the sequenceof amino acids.The amino acids join together to form a protein molecule.If genes produce incorrect proteins, cells may not function properly. This is the cause of many inherited diseases.
10 B3h – More of the same ADVANTAGES OF CLONING DISADVANTAGES OF CLONING Why clone animals? Animals or plants with special qualities could be mass produced to help in the manufacture of important drugs.DISADVANTAGES OF CLONINGAbout 98% of cloning efforts fail.Usually a cloned embryo dies before birth but sometimes afterwards too.Stem cells have the ability to differentiate into different sorts of cells – muscle, liver, bone, etcCells lose this ability as the human gets older