Biology Term Exam PDF

BIOLOGY TERM EXAM (a) REPRODUCTION AND INHERITANCE (3.1) -SEXUAL REPRODUCTION: Fertilisation of two sex cells (one gamete from each parent) produced by Meiosis to form a zygote which will develop into non-identical offspring -ASEXUAL REPRODUCTION: Reproduction by a single parent to produce gene...

BIOLOGY TERM EXAM (a) REPRODUCTION AND INHERITANCE (3.1) -SEXUAL REPRODUCTION: Fertilisation of two sex cells (one gamete from each parent) produced by Meiosis to form a zygote which will develop into non-identical offspring -ASEXUAL REPRODUCTION: Reproduction by a single parent to produce genetically identical offspring (clones) via Mitosis. (3.2) FERTILISATION: Fusion of haploid gamete to produce diploid zygote that undergoes Mitosis to develop into an Embryo An Egg Cell and Sperm Cell are haploid gametes, containing 23 chromosomes (half of the 46 chromosomes in a Zygote) Due to this, reproducing requires the fusion of two haploid gametes via fertilisation to form a diploid Zygote containing 46 chromosomes (half from each parent) As diploid Zygote carries a mixture of genetic information from both parents, Zygote will undergo Mitosis to develop into an embryo exhibiting genetic variation FLOWERING PLANTS General structure of flowers: - Sepals; leaf shaped structure on the oute most part of the flower that protects the unopened flower - Petals; brightly coloured leaves surrounding the reproductive part of the flower to attract pollinators - Stamens; male part of the flower composed of the filaments and anther - Filament; slender stalk supporting the anther to make it accessible for pollinators - Anthers; lobes to top of the filament that produces the male gamete of the flowering plant - Stigma; sticky receptive part that is responsible for catching pollen - Style; tube shaped connection between stigma and ovule that elevates stigma to catch pollen - Ovule; structure that contains female reproductive cells that develop the seed after fertilisation ( 3.3 and 3.4) INSECT POLLINATED FLOWER: Flower that distributes Pollen via Insects WIND POLLINATED FLOWER: Flower that distributes Pollen via Wind. (3.5) TEST TUBE A ( Everything present) : seeds germinated; yes TEST TUBE B (Water present : seeds germinated ; No TEST TUBE C ( Temperature) : seeds germinated ; No TEST TUBE D ( Oxygen) seeds germinated; No (3.6) GERMINATION: Process by which Seed emerges from period of dormancy and begins to sprout Structure of a seed: During germination , the absorption of water triggers the plants hormones, stimulating the synthesis of amylase. As amylase breaks down food of starch into c glucose to be used as energy for growth via aerobic respiration, thus continues until seedling can carry out photosynthesis as a source of glucose for energy. (3.7) Reproduce naturally ( runners): in runners cells split off from the parents to grow side nuanced , specializing into root hair cells , as a result planteles will grow roots and plant will evolve , forming a plant that is identical to the parent. Reproduce artificially ( cuttings ): currants have a specific plant tissue that is selected from stock plant and is sterilized , then the sample is ex planted and grown is a special dish containing sterile nutrient agar gel , it’s then treated with growth hormones to stimulate the root development, as a result the growing sprout can be divided and separated into new samples , once they are developed the cloned plant is then transferred to soil. (3.8) MALE REPRODUCTIVE SYSTEM: All organs responsible for the production of Sperm (the male gamete) Sex gland : gland that secretes fluids containing nutrients and mucus with sperm cells to form semen Urethra : tube inside penis that conducts semen from sex gland to outside of body via penis Testicles : two oval shaped organs held outside by scrotum , to synthesize sperm and testosterone FEMALE REPRODUCTIVE SYSTEM: All organs responsible for the production of Egg cell (the female gamete) Bladder : muscular sac that stores urine Oviduct: tube lined to brush cells released from ovary to uterus for fertilisation Ovary: tissue where egg cells mature ready for ovulation , responsible for estrógenos and progesterone Uterus: organ with thick muscular walls where fertilised egg will be implanted to develop into a foetus. Cervix : ring músculo that closes to protect developing foetus and opens to form birth canal. Vagina : muscular passage leading to uterus which penis can enter during sexual intercourse to deliver sperm. (3.9) MENSTRUAL CYCLE: Changes that occur within female reproductive system for pregnancy to be viable Each menstrual cycle lasts roughly for one month and begins at puberty before ending with menopause Oestrogen: needed for puberty, the menstrual cycle, pregnancy, bone strength and other functions of the body Progesterone: to prepare the lining of your uterus for a fertilised egg to implant and grow. (3.11) (3.12) The placenta is lined with chorionic villi to increase surface area for diffusion of materials between mother and foetus, allowing efficient material exchange. Materials like oxygen , Nutrients, vitamins , antibodies and water diffuse across placenta from mother to foetus. Waste materials like carbon dioxide, and other waste products diffuse across the placenta from foetus to mother. Estrogen stimulates the growth of uterine muscles and development of mammary glands in breasts , progesterone maintains the uterus lining and reduces uterine contractions. The uterus is surrounded by amniotic fluid , its incompressible funnciotining as an efficient shock absorber to protect foetus from impact , it created buoyancy to ensure foetus does not have to support its own weight whilst the skeletal system develops. (3.13) Effects of oestrogen - development of breasts - Growth of body hair - Beginning of menstrual cycle Effects of testosterone - Growth of penis and testes - Growth of facial and body hair - Msjcke development - Voice breaking - Sex drive - Sperm production (a) FOOD PRODUCTION CROP PLANTS (5.1) GLASSHOUSES: Glass building used to grow Plants in an enclosed environment POLYETHENE TUNNELS: Polyethene tunnel that allows Plants to be grown in an enclosed and protected environment outdoors Enclosed environments protect drops from the effects of weather, wind rains and extreme temperatures. Also it protects them from pests or disease that can inhibit plant growth. Enclosed environments trap heat from the sun , creating a warm climate close to primum temperature of plant enzymes increasing rate of photosynthesis to promote plant growth. Glass house - Small scales of glasshouses allow all conditions to be controlled, to increase growth and photosynthesis, artificial heating is added to increase temp ofwards optimum for increased enzyme activity in plants for photosynthesis. Additional CO2 relaxed via burning paraffin lamp for photosynthesis. Polythene tunnels - Large scale of these tunnels allows for farmers and machines to work inside to increase crop yield, enclosed enviro Kent creates a warmer temperature close to optimum temperature of plant enzyme than if they where outside. (5.2) CARBON DIOXIDE As glasshouses are enclosed, CO2 conc can be controlled, farmers burn paraffin lamps to increase CO2 levels in glasshouses , as the concentration increases so does the photosynthesis rate. However as concentration increases beyond a certain point , photosynthesis and plateau will be a limiting factor. TEMPERATURE As glasshouses are enclosed, heat from the sun is trapped to create a warm climate , was temperature increased towards the optimum , the rate of photosynthesis increases. This is because increase in temp allows optimum enzyme activity for photosynthesis. However as temp increases above optimum enzymes will denature ( irreversible) causing the rate of photosynthesis to decrease = crop yield decrease. (5.3) Fertilised is added to the soil , this is loaded by various nutrients that provide favorable conditions for plant growth like: - increase biomass ( Nitrates and phosphates ) - Increase rate of respiration to release energy for growth ( phosphates) - Allowing enzyme reactions to occur to produce energy ATP energy ( Potassium The 3 minerals (NPK) : - Nitrates - Phosphates - Potassium (5.4) PEST CONTROL: Use of Pesticides (chemicals such as Fungicides, Herbicides and Insecticides) to control pests from consuming or damaging Plants PESTICIDE FUNCTION ADVANTAGE DISADVANTAGE Fungicides ——— kills fungi ——— efficient as quick method ——— pests can develop a resistance Herbicides ——— kills herbs ——— immediate effect ——— may kill other organisms Insecticides ——— kills insects ——— Targets and kills all popul. ——— toxic to food chain BIOLOGICAL CONTROL: Natural method to control pests using organisms that feed on pests ADVANTAGES AND DISADVANTAGES Natural method ——— may kill other organisms Resistance ——— time lag in effect Ability to target specific species ——— cannot kill the entire populfsion