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BIOLOGY EDEXCEL IGCSE DOUBLE
AWARD
Physical appearance of an organism (e.g. blue eyes) - correct answer Phenotype Genotype - correct answer The sets of genes (alleles) that an organism possesses (e.g. Bb) Allele - correct answer A different version of a gene Heterozygous - correct answer When the two alleles are different (e.g. Bb) Homozygous - correct answer When two alleles are identical (e.g. BB or bb) Dominant - correct answer Allele which controls the characteristic whenever present Recessive - correct answer Allele whose characteristic only shows up when it is present on both chromosomes. Co-dominance - correct answer When two alleles have equal dominance (they will both be expressed). DNA molecule - correct answer Two strands coiled to form a double helix, the strands being linked by a series of paired bases. Bases - correct answer Adenine (A) - Thymine (T) and Cytosine (C) - Guanine (G)
Diploid number of chromosomes in humans - correct answer 46 Haploid number of chromosomes in humans - correct answer 23 Nucleotide - correct answer The "backbone" of the DNA strands, a single nucleotide contains one of the 4 bases, a deoxyribose sugar and a phosphate group. DNA replication (6) - correct answer 1) Hydrogen bonds break (DNA helices enzyme)
- Double helix unwinds to 2 separate strands
- Each strand attracts new nucleotide
- Nucleotides line up according to the base pairing rule (C-G, A-T)
- The enzyme polmerase joins up the nucleotides to form 2 identical DNA molecules
- Each new DNA molecule contains one strand from the parent DNA and one new complementary strand. Mutation - correct answer A random change in the DNA of a cell. Chromosome - correct answer Contains one double stranded DNA molecule. The DNA is folded and coiled around proteins called histones so it can fit into a small space. Mitosis definition - correct answer The cell division of normal body cells. Required for growth and repair of tissues, asexual reproduction. Mitosis process (5) - correct answer 1) The DNA of each chromosome is replicated to form two identical sister-chromatids.
- The chromatids are attached to each other at the centromere. The membrane around the nucleus breaks down.
- The chromosomes line up at the centre of the cell and cell fibres pull them apart.
- The centromere splits and the two sister chromatids move to the opposite ends of the cell.
- Two new nuclei form around the two sets of chromosomes, cytoplasm divides.
Carpel - correct answer The female reproductive organs of a plant - collective term for the style, stigma and ovary. Fertilisation - correct answer The fusion of the nuclei of the male and female gametes Filament - correct answer The long stalk that connects the anther to the rest of the plant. Also part of the stamen. Ovary - correct answer Contains the ovule, which encloses the female gamete. It's wall may become part of the fruit on fertilisation Ovule - correct answer Site of ovum production. Found in the ovary. Ovum - correct answer Female gamete Pollen grain - correct answer Male sex cell or gamete. Pollination - correct answer The transfer of pollen from the anther to the stigma of a plant of the same species. Stamen - correct answer The male reproductive organ of a plant - collective term for the anther and filament. Stigma - correct answer Part of the female reproductive organs. Surface on which the pollen grains containing male gametes may be disposed Style - correct answer The part of the carpel that joins the stigma to the ovary. Holds stigma in place Nectary - correct answer Produces nectar- a sugary liquid for pollinating insects
Sepal - correct answer protects the flower from drying out and fungal attacts Cross-pollination - correct answer Pollen transfer between different flowers of the same species. Involves genetic variation but is risky as a vector (carrier) is required. Self-pollination - correct answer involves pollen transfer between the stamen and stigma of the same flower. It is less risky and ensures survival of species but limits genetic variation. Pollen Tube - correct answer Grows down the style from the pollen grain and acts as a channel to deliver the male gamete to the ovum. Seed Germination - correct answer Requires water, oxygen and a good temperature Seed dispersal - correct answer Allows plants to colonise new areas. There's less competition for for resources and it stops overcrowding Runners - correct answer Used by plants for Asexual reproduction Aorta - correct answer Carries oxygenated blood from the heart to the body Pulmonary artery - correct answer Carries deoxygenated blood from the heart to the lungs. Pulmonary vein - correct answer Carries oxygenated blood from the lungs to the left atrium. Left ventricle - correct answer Chamber that pumps oxygenated blood out to the body through the aorta - thicker muscle wall
N - MRSHGREN - correct answer nutrition, needing of food Test for glucose - correct answer 1. Warm water bath
- Benedict solution turns brick red Test for Starch - correct answer iodine solution turns blue or black. Definition of enzyme - correct answer Biological catalysts that control all the reaction in a cell What happens when the active site stops the enzyme working? - correct answer Denatures What is Aerobic respiration? - correct answer Respire that requires oxygen Equation for Aerobic respiration - correct answer Glucose + Oxygen = Carbon dioxide + Water + Energy What is Anaerobic respiration? - correct answer Respire that doesn't requires oxygen Equation for Anaerobic respiration - correct answer Glucose = Ethanol + Carbon dioxide + some energy Test for carbon dioxide - correct answer bubbles in limewater, turns cloudy Definition of diffusion - correct answer movement of particles from an area of high concentration to an area of lower concentration. It is caused by random movement of particles.
Definition of Osmosis - correct answer Only water moves across a partially permeable membrane from an area of high concentration to a low concentration Definition of active transport - correct answer Substances are moved against a concentration gradient or across a selectively permeable membrane. Uses energy produced by cellular respiration All specialized cells in order - correct answer Organelles, cells, tissues, organs, organ systems Features of Plants - correct answer - multicellular
- carry out photosynthesis Features of Animals - correct answer - Multicellular
- cannot carry out photosynthesis Features of Fungi - correct answer - Can be multicellular or unicellular
- cannot carry out photosynthesis Features of Protoctists - correct answer - Can be unicellular or multicellular
- can carry out photosynthesis Features of Bacteria - correct answer - Single-celled organisms
- some can carry out photosynthesis Trachea - correct answer Tube with incomplete rings of cartilage carries air to lungs bronchus - correct answer carries air to lung
lipase breaks down - correct answer Lipid into fatty acids and glycerol What are proteins - correct answer They are long chains of amino acids found in foods What are lipids - correct answer they are made up of carbon, hydrogen, and oxygen Definition of absorption - correct answer The products of digestion are absorbed into your bloodstream in the small intestine. Definition of Assimilation - correct answer The digested food products are absorbed into the cells of the body by diffusion Definition of Egestion - correct answer Waste product that the body gets rid of by passing out the of anus What is the function of bile - correct answer Released to neutralised stomach acid and emulsify fats Definition of emulsifying agents - correct answer Substances that are soluble in both fat and water and enable fat to be uniformly dispersed in water as an emulsion. The alimentary canal includes - correct answer The mouth, oesophagus, stomach, small intestine, large intestine and pancreas. Where is bile made from and where does it stored? - correct answer Liver and stored in gall bladder How is the waste product moved through the gut by peristalsis - correct answer wave-like contractions create a squeezing action, moving down the gut.
The features of arteries - correct answer Thick muscular wall, and thick elastic fibre Small lumen Carries blood under high pressure carry oxygenated blood away from the heart The features of veins - correct answer Thin layers of muscle wall, and thin elastic fibre Big lumen Carries blood under low pressure carry deoxygenated blood towards the heart What is valves - correct answer It controls the flowing of heart in the blood, it stops the blood flowing backwards What are memory cells - correct answer They memorise the features of a pathogen, so if they invade the person again, they act more quickly and produce large number of the right antibody to prevent disease. Definition of plasma - correct answer Yellow liquid that transport dissolved food molecules, carbon dioxide and urea Adaptation of the red blood cells - correct answer Contain haemoglobin to carry oxygen to the cells. it has a thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. Name the two types of white blood cells - correct answer Lymphocytes and Phagocytes Which white blood cells produce antibodies - correct answer Lymphocytes
What is the kidney's role? - correct answer Excretion and osmoregulation What does selective reabsorption of glucose occurs? - correct answer The proximal convoluted tubule Examples of homeostasis - correct answer blood pH, body temperature, O levels, hormones, What does coordinated response requires? - correct answer Stimulus, a receptor and an effector Features of nervous system - correct answer Transport by nerve cells Electrical impulses Travel fast and instant effect Response is usually short lived Act on individual cells Features of Endocrine system - correct answer Transport hormones by bloodstream Chemical impulses Slowly and take longer to act Response is long lasting Widespread effect on different organs What is adrenaline? - correct answer The fight or flight hormones What is oestrogen? - correct answer The female hormone produced by the ovaries What is progesterone? - correct answer Like the estrogens, a female sex hormone that regulate the menstrual cycle, it completes the development of the uterus lining
What is testosterone? - correct answer Male sex hormone that controls the development What is insulin? - correct answer Insulin is a hormone which converts glucose into glycogen (when blood sugar levels are too high) What is ADH? - correct answer produced in the pituitary gland, reabsorbs water What is tropism? - correct answer a plant's response to an external stimulus What is the three tropism response that a plant have? - correct answer Phototropism, geotropism, hydrotropism What is the three stimulus of a plant? - correct answer Light, gravity, water What is the light response hormone in plant? - correct answer Auxin What is the effect of geotropism - correct answer Stem goes negative, roots goes positive What is photosynthesis? - correct answer The process by which a cell captures energy in sunlight and uses it to make food. What is the word equation of photosynthesis? - correct answer Carbon dioxide + water = glucose + oxygen How does the structure of lead is adapted for photosynthesis - correct answer Thin and flat Short distance to diffuses As much light can be absorbed
Examples of asexual reproduction plant - correct answer Runners, bulbs and tubers What is pollination? - correct answer The transfer of pollen from the anther to the stigma Examples of pollination - correct answer Cross pollination Wind pollination Self pollination Insect pollination Where does fertilisation takes place in plant? - correct answer Ovule in the ovary What is population? - correct answer Group of individuals of the same species that live in the same area What is community? - correct answer All the different populations that live together in an area What is habitat - correct answer The place where specific organisms live What is ecosystem? - correct answer A distinct self supporting system of organisms interacting with each other and with a physical environment How to use quadrants to sample from a habitat? - correct answer Randomly sample Measure the area of different species What is a trophic level? - correct answer Each step in a food chain or food web
What are the two ecological pyramids? - correct answer Pyramids of numbers Pyramids of biomass Why ain't all the energy transferred to the next level? - correct answer Some parts are not eaten Some parts are not digested Some of the mateáis absorbed form excretory products Loss to respiration energy Stages of carbon cycle - correct answer Respiration, photosynthesis, decomposition, combustion what is global warming? - correct answer The increased levels of carbon dioxide trapped inside the greenhouse gases, which caused rise of temperature. What is the effect of global warming? - correct answer 1. sea level would rise because polar ice melts
- causing the flood in some countries
- Change the nature of many ecosystems
- Change in global rainfall What is Carbon monoxide? - correct answer a toxic gas created when there's an incomplete combustion. It binds with haemoglobin in blood, cause lack of oxygen transported inside the body. What is sulfur dioxide? - correct answer An important pollutant as it is a major constituent of acid rain. it's formed when fossil fuels are burned. What is the effect of acid rain? - correct answer Kills life in streams and lakes damages limestone/buildings
Definition of Chromosomes - correct answer Where you can find DNA in the nucleus of a cell Definition of Gene - correct answer A small section of DNA that determines a particular feature is called a gene Definition of Genetically identical - correct answer Each new cell receives exactly the same type and amount of DNA Name the 4 molecules inside the DNA - correct answer A-adenine T-thymine G-guanine C-cytosine What is the structure of DNA called? - correct answer Double helix structure What is mutation? - correct answer A random change in the DNA of a cell it can happen in individual genes or in whole chromosomes What happens during natural selection? - correct answer - random mutation occurs
- competition for food space and mate
- The one survives successfully passed the feature to their offsprings.
- The one that doesn't suit the environment dies
- This happens over many generation. What is mitosis? - correct answer Mitosis produces identical diploid body cells for growth and repair What is meiosis? - correct answer Meiosis produces haploid non-identical sex cells, or gametes
What is the difference between a diploid and a haploid? - correct answer - Diploid is a cell that contains two sets of chromosomes
- haploid is a sex cell gamete that contains one set of chromosomes What does the DNA make? - correct answer It makes a specific proteins needed in biological processes Definition of Phenotype - correct answer The visible characteristics of an organism which occur as a result of its genes Definition of Genotype - correct answer The genotype of an organism demonstrates the alleles present for a particular characteristics
- if the two of the same alleles for a gene are present, the genotype is said to be homozygous
- if they are said to be different they are heterozygous Definition of evolution - correct answer The change of inherited characteristics within a population over time through natural selection, which may result in the formation of a new species Definition of dominant - correct answer An allele that always expresses itself whether it is partnered by a recessive allele or by another like itself Definition of recessive - correct answer Describes the variant of a gene for a particular characteristic which is masked or suppressed in the presence of the dominant variant. A recessive gene will remain dormant unless its is paired with another recessive gene Definition of alleles - correct answer Different forms of the same gene What pair of chromosome makes a male and what pair makes a female? - correct answer XX female XY male
