Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 1 Characteristics and classification of living organisms KEY movement DEFINITION ü an action by an organism or part of an organism ü causing a change of position or place respiration ü the chemical reactions in cells ü that break down nutrient molecules and release energy for metabolism sensitivity ü ability to detect or sense stimuli in the internal or external environment ü and to make appropriate responses growth ü permanent increase in size and dry mass ü by an increase in cell number or cell size or both excretion ü removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), ü toxic materials, ü and substances in excess of requirements nutrition ü taking in of materials for energy, growth and development; ü plants require light, carbon dioxide, water and ions; ü animals need organic compounds and ions and usually need water species ü group of organisms that can reproduce ü to produce fertile offspring binomial system ü naming species as an internationally agreed system ü in which the scientific name of an organism is made up of two parts ü showing the genus and species KEY DEFINITION| Notes v3.18| Google: vbest 1 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Morphology ü the study of the form, or outward appearance, of organisms. Anatomy ü the study of their internal structure, as revealed by dissection. KEY DEFINITION| Notes v3.18| Google: vbest 2 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 2 Organisation of the organism KEY tissue DEFINITION ü a group of cells with similar structures, ü working together to perform a shared function ü Eg. Bone, nerve, muscle, epidermis, xylem organ ü a structure made up of a group of tissues, ü working together to perform specific functions ü Eg. Stomach, heart, lungs, intestines, brain, eyes organ system ü a group of organs with related functions, ü working together to perform body functions ü Eg. Nervous and circulatory system Chapter 3 Movement in and out of cells KEY diffusion DEFINITION ü net movement of particles ü from a region of their higher concentration to a region of their lower concentration ü down a concentration gradient, ü as a result of their random movement osmosis ü ü ü ü net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane active transport ü ü ü ü the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration KEY DEFINITION| Notes v3.18| Google: vbest 3 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 5 Enzymes KEY catalyst DEFINITION ü a substance that increases the rate of a chemical reaction ü and is not changed by the reaction enzymes ü proteins that function as biological catalysts Chapter 6 Plant nutrition KEY photosynthesis DEFINITION ü the process by which plants manufacture carbohydrates ü from raw materials using energy from light limiting factor ü something present in the environment ü in such short supply that it restricts life processes KEY DEFINITION| Notes v3.18| Google: vbest 4 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 7 Human nutrition KEY ingestion DEFINITION ü taking of substances ü e.g. food and drink, into the body through the mouth mechanical digestion ü breakdown of food into smaller pieces ü without chemical change to the food molecules chemical digestion ü breakdown of large, insoluble molecules ü into small, soluble molecules absorption ü movement of small food molecules and ions ü through the wall of the intestine into the blood assimilation ü movement of digested food molecules ü into the cells of the body where they are used, ü becoming part of the cells egestion ü passing out of food that has not been digested or absorbed, as faeces, through the anus Chapter 8 Transport in plants KEY transpiration translocation DEFINITION ü loss of water vapour from plant leaves ü by evaporation of water at the surfaces of the mesophyll cells followed ü by diffusion of water vapour through the stomata ü movement of sucrose and amino acids in phloem: ü from regions of production (source) ü to regions of storage OR to regions where they are used in respiration or growth (sink) KEY DEFINITION| Notes v3.18| Google: vbest 5 vbest.edu.my | MS JOAN YUEN Cambridge IGCSE A* Biology Chapter 10 Diseases and immunity KEY pathogen DEFINITION ü disease-causing organism transmissible disease ü disease in which the pathogen ü can be passed from one host to another active immunity ü defence against a pathogen ü by antibody production in the body Chapter 12 Respiration KEY aerobic respiration DEFINITION ü chemical reactions in cells ü that use oxygen to break down nutrient molecules to release energy anaerobic respiration ü chemical reactions in cells ü that break down nutrient molecules to release energy without using oxygen Chapter 13 Excretion in humans KEY deamination DEFINITION ü the removal of the nitrogen-containing part of amino acids ü to form urea KEY DEFINITION| Notes v3.18| Google: vbest 6 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 14 Coordination and response KEY synapse DEFINITION ü a junction between two neurones sense organs ü groups of receptor cells ü responding to specific stimuli: light, sound, touch, temperature and chemicals hormone ü chemical substance, ü produced by a gland and carried by the blood, ü which alters the activity of one or more specific target organs homeostasis ü maintenance of a constant internal environment gravitropism ü response in which parts of a plant ü grow towards or away from gravity phototropism ü a response in which parts of a plant ü grow towards or away from the direction from which light is coming Chapter 15 Drugs KEY drug DEFINITION ü any substance taken into the body ü that modifies or affects chemical reactions in the body KEY DEFINITION| Notes v3.18| Google: vbest 7 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 16 Reproduction KEY asexual reproduction DEFINITION ü process resulting in the production of genetically identical offspring ü from one parent sexual reproduction ü process involving the fusion of the nuclei of two gametes (sex cells) ü to form a zygote ü and the production of offspring that are genetically different from each other fertilisation ü fusion of gamete nuclei pollination ü transfer of pollen grains from the anther to the stigma self-pollination ü transfer of pollen grains from the anther of a flower to the stigma ü of the same flower or different flower ü on the same plant cross-pollination ü transfer of pollen grains from the anther of a flower to the stigma ü of a flower on a different plant of the same species sexually transmitted infection ü infection that is transmitted ü via body fluids through sexual contact KEY DEFINITION| Notes v3.18| Google: vbest 8 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 17 Inheritance KEY inheritance DEFINITION ü transmission of genetic information ü from generation to generation chromosome ü thread-like structure of DNA, ü carrying genetic information in the form of genes gene ü length of DNA that codes for a protein allele ü a version of a gene haploid nucleus ü nucleus containing a single set of unpaired chromosomes, ü e.g. in gametes diploid nucleus ü nucleus containing two sets of chromosomes, ü e.g. in body cells mitosis ü nuclear division ü giving rise to genetically identical cells meiosis ü reduction division ü in which the chromosome number ü is halved from diploid to haploid resulting in genetically different cells genotype ü genetic make-up of an organism in terms of the alleles present phenotype ü observable features of an organism KEY DEFINITION| Notes v3.18| Google: vbest 9 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN homozygous ü having two identical alleles of a particular gene heterozygous ü having two different alleles of a particular gene dominant ü allele that is expressed if it is present recessive ü allele that is only expressed ü when there is no dominant allele of the gene present sex-linked characteristic ü characteristic in which the gene responsible is located on a sex chromosome ü and that this makes it more common in one sex than in the other Chapter 18 Variation and selection KEY variation DEFINITION ü differences between individuals ü of the same species gene mutation ü a change in the base sequence of DNA adaptive feature ü inherited feature ü that helps an organism to survive and reproduce ü in its environment fitness ü the probability of an organism ü surviving and reproducing in the environment in which it is found adaptation ü process, resulting from natural selection, ü by which populations become more suited to their environment over many generations KEY DEFINITION| Notes v3.18| Google: vbest 10 Cambridge IGCSE A* Biology vbest.edu.my | MS JOAN YUEN Chapter 19 Organisms and their environment KEY food chain DEFINITION ü showing the transfer of energy ü from one organism to the next, beginning with a producer trophic level ü the position of an organism in a food chain, food web, pyramid of numbers or pyramid of biomass food web ü a network of interconnected food chains producer ü an organism that makes its own organic nutrients, ü usually using energy from sunlight, ü through photosynthesis consumer ü an organism that gets its energy ü by feeding on other organisms herbivore ü an animal that gets its energy ü by eating plants carnivore ü an animal that gets its energy ü by eating other animals decomposer ü an organism that gets its energy ü from dead or waste organic material population ü a group of organisms of one species, ü living in the same area, at the same time community ü all of the populations of different species in an ecosystem KEY DEFINITION| Notes v3.18| Google: vbest 11 Cambridge IGCSE A* Biology ecosystem vbest.edu.my | MS JOAN YUEN ü a unit containing the community of organisms and their environment ü interacting together, e.g. a decomposing log, or a lake Chapter 20 Biotechnology and genetic engineering KEY genetic engineering DEFINITION ü changing the genetic material of an organism ü by removing, changing or inserting individual genes Chapter 21 Human influences on ecosystems KEY sustainable resource DEFINITION ü one which is produced as rapidly ü as it is removed from the environment ü so that it does not run out sustainable development ü development providing for the needs ü of an increasing human population ü without harming the environment KEY DEFINITION| Notes v3.18| Google: vbest 12