B1 You and Your Genes

1. Nitrogen bases: Adenine pairs with Thymine Guanine pairs with cytosine Human male chromosomes DNA is a double helix Genetic instructions are in the form of a code made up of 4 bases DNA with bases Inheritance- Parents who are both carriers of the Cystic fibrosis allele (c). Parents Cc x Cc Gametes C or c x C or c (egg/sperm) C c Possible Outcomes C 75% Normal c 25% sufferers B1 You and Your Genes Lobed ears are dominant over ears with no lobes Cytoplasm: chemical reactions take place Cell membrane: Controls movement into and out of the cell Nucleus: contains genetic information Mitochondria: Respiration takes place providing energy Cystic Fibrosis Caused by recessive allele (so two copies of allele are needed). A thick sticky mucus is produced affecting air passages and digestive systems Protein synthesis: Each gene codes for a particular protein

2. Genetic Testing To determine any faulty alleles being passed on Huntington's Disease Caused by dominant allele (one copy of allele are needed). Loss of memory and neurone damage in the brain PGD - Used to screen embryos for faulty alleles Variation – caused by dominant/recessive alleles and environment Stem cells - cells with no specific function. Can be turned into any cell

3. Heart pumps blood around the body Arteries transport blood away from the heart Veins transport blood into the heart Capillaries exchange materials with tissues Producing antibodies Vasoconstriction and Vasodilation Step 2: The cell produces antibodies to “fit” the pathogen Temperature Monitored by thermoregulatory centre in brain and receptors in skin. Too Hot -hair lies flat -blood vessels dilate so heat lost through skin -sweat produced Too Cold -Goosebumps & hairs trap air -blood vessels constrict -no sweat -shiver, respiration releases heat B2 Keeping Healthy Step 1: The lymphocyte “sees” the pathogen (microbe) Step 4: The pathogens are “eaten” by the white blood cells Step 3: The antibodies fit onto the pathogens and cause them to “clump”

4. Damaged cilia in a smoker’s air way Resistant Bacteria's – these are bacteria's that have mutated and antibiotics no longer are able to kill them. Vaccines – dead or live proteins injected into the body. The body will make antibodies for the antigens of the microbes. Risk Factor – when you increase the risk of getting the disease by doing the factor i.e. drinking alcohol Cause/Correlation A factor that can cause an outcome. Correlation means that there is a common link between a factor and outcome. Water Homeostasis – controlled by negative feedback of ADH.

5. EVIDENCE OF EVOLUTION What evidence is there that evolution is happening? • HUMAN EVOLUTION • How are human beings different from apes? • bigger b_____ • w_____ upright NATURAL SELECTION D______ proposed the theory of e______ to explain how species change over time. There is v_______ between individuals, those that are better a_______ are more likely to s________ and r________, passing on favorable characteristics. • Fossil record is incomplete because: • Some body part decay quickly • Fossilisation is rare • There may still be fossils we have not found NATURAL ECOSYSTEM Ocean, dessert, grass land, rain forest ARTIFICIAL ECOSYSTEM Farm land, Aquarium, green house The up and down pattern of predator and prey population is called cyclic fluctuations LAMARCK Believed that acquired characteristics can be inherited Photosynthesis happens only during day but respiration happens both during day and night B3 Life on Earth The presence or absence of an indicator species is used to estimate levels of pollution Example: Lichens Mule Liger • CHARLES DARWIN: Developed theory of natural selection based on survival of fittest • Genes pass on the successful characteristics to the next generation • COMPETITION • What resources are plants and animals in competition for? • Space • Food • Mate • EXTINCTION • Causes of extinction: • increased c_______ • New p________ • e_________ change • new d_________ Adaptation: features which help a plant or animal survive in an extreme environment,. Example: Polar bear, Camel and cactus Sustainable development is taking things from the environment but leaving enough behind to ensure a supply for the future and prevent damage Zebroid Geep MUTUALISM: When both Organisms benefit, example: Pea plant and nitrogen – fixing bacteria

6. “Species” means “a group of similar organisms” which are capable of interbreeding to produce fertile offspring, e.g. dogs Hybrids: Hybrids are the result of breeding two animals form different species, they cannot reproduce and are sterile. Example: Tiger +Lion = Tigon Classifying organisms Organism Interspecific Competition – between two different species Intraspecific Competition – between the same species Labrador Poodle Labradoodle Plants Animals + = Have backbone No backbone Vertebrates Invertebrates Origin of Species Nitrogen & Carbon Cycle – how these elements form a cycle, uses of decomposition, respiration, consumption and photosynthesis Amphibians Birds Reptiles Fish Mammals Biodiversity – different species living in the same habitat/ecosystem.