1. Plant Nutrients Nitrates-to make proteins Magnesium-to make chlorophyll Potassium-aids respiration Phosphorous-aids respiration Many mitochondria Streamlined What is the function of each organelle? 3 Limiting factors -light -temperature -CO 2 At first as CO 2 increases so does photosynthesis but only up to a certain point. Here light or temperature is the limiting factor. Photosynthesis Carbon dioxide + Water Glucose + Oxygen Used in lungs; O 2 diffuses into the blood and CO 2 diffuses into lungs Keywords: Diffusion, Chloroplast, Vacuole, Cell wall, Nucleus, Mitochondria, Homozygous Keywords: Allele, Dominant, Recessive, Mitosis, Meiosis, Enzyme, Substrate, Active Site, Denatured, pH, Concentration gradient Light and chlorophyll are also needed Cell Wall Cell Membrane Nucleus Vacuole Chloroplast Cytoplasm Factors affecting diffusion Temperature Concentration gradient Diffusion distance Surface area : Volume Respiration (in mitochondria) Aerobic (all the time)Anaerobic (when exercising) Glucose + O 2 → H 2 O + CO 2 (+ energy) Glucose → Lactic acid (+ energy) Energy used for: heat, movement, build large molecules Incomplete breakdown of glucose (less energy released) Oxygen debt (need oxygen to get rid of lactic acid) Causes of extinction Disease Hunting / predators Loss of food / prey Loss of habitat / natural disaster Climate change Speciation Isolation Genetic Variation Natural Selection Speciation Population isolated due to… New population exhibit variation New population no longer able to interbreed with old population Some individuals more likely to survive and reproduce Phloem Xylem Stored as starch Sperm cell In the ROOTS of plants! Large surface area for uptake of water & minerals Mitochondria Ribosomes In the LEAVES of plants! Lots of chloroplasts for photosynthesis. Palisade cell Root hair cell Cells Tissues Organs Organ systems Leaves Waxy cuticle-keeps water in Epidermis - Protection Palisade mesophyll layer- cells contain lots of chloroplasts to capture light Stomata on lower surface to allow gases in/out Spongy mesophyll layer has air spaces to allow gases to move between cells Animal tissues Plant tissues MuscleEpidermis GlandularMesophyll EpithelialPhloem/ xylem

2. Enzymes and digestion Large molecules are broken down so they can be absorbed. -Amylase breaks down starch into sugars in the mouth and small intestine. -Proteases breakdown proteins into amino acids in the stomach and small intestine. -Lipases breakdown fats into fatty acids and glycerol in the small intestine. - Enzymes in the stomach work best at acidic pH’s; enzymes in the small intestine work best at alkaline pH’s (bile neutralises acid from the stomach and provides these conditions). Starchglucose Inheritance- Parents who are both carriers of the Cystic fibrosis allele (c). ParentsCc x Cc GametesC or c x C or c (egg/sperm) C c Possible Outcomes C 75% Normal c 25% sufferers 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 Enzymes have an optimum temperature and pH. Changes in pH/temp can denature the enzyme so its shape changes and the substrate can’t bind to the active site 1) Enzymes –biological catalysts that speed up reactions yet remain unchanged e.g. respiration in the mitochondria 1) Enzyme and substrate 2)Substrate binds to active site 3) Substrate is broken down Uses of Enzymes -Biological washing powders -In baby foods (proteases) -In slimming foods- fructose is made using isomerases. Fructose is sweeter than glucose so less is needed. 2)3) Mitosis-used for normal cell growth 1) Parent cell 2) Chromosomes make identical copies of themselves 3) One cell division occurs 4)Two daughter cells form each with 46 identical chromosomes to the parent cell Meiosis –used to make the sex cells (gametes) -the chromosomes are copied -two cell divisions to give four cells - Cells contain half original chromosome number Polydactyly-Caused by dominant allele (so only one of allele are needed). Affects the number of digits. CCCc cc 46=chromosomes in normal cell 23=chromosomes in sex cells A cell nucleus contains 46 Chromosomes, which carry genes. Different versions of genes are called alleles. A chromosome is a DNA double helix Physical factors affecting distribution of organsism: Temperature, Nutrients, Light, Water, CO 2 /O 2 Proteins Made of amino acids Examples = enzymes, hormones, antibodies Stem cells: unspecialised; differentiate to form other cells (used for repair); from bone marrow or embryos ProsCons Treat illnessExpensive Ethics of using embryo A gene codes for specific sequence of amino acids, to make a specific protein FOSSILS! Early organisms = soft- bodied = few fossils Fossilisation = rapid burial, no oxygen, replacement of tissues, time, discovery…