Ocr A level biology paper 2 EXAM QUESTIONS AND ANSWERS UPDATED 2024/2025 ALL ANSWERS 100%, Exams of Biology

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Phenotype - CORRECT ANSWERS Characteristics of an organism as a result of the expression of its genotype and the environment. Gene - CORRECT ANSWERS Section of a chromosome that codes for a polypeptide. Allele - CORRECT ANSWERS Alternative version of the same gene. Gene locus - CORRECT ANSWERS Location of a gene on a chromosome. Dominant allele - CORRECT ANSWERS Allele that is always expressed in the phenotype. Recessive allele - CORRECT ANSWERS Allele that is only expressed in the phenotype when there are two of them i.e. in a homozygote. Codominant allele - CORRECT ANSWERS Both alleles are expressed in the phenotype. Multiple alleles - CORRECT ANSWERS More than 2 alleles for a particular gene. Sex linkage - CORRECT ANSWERS Characteristic or trait controlled by a gene found on the sex chromosomes. Homologous chromosomes - CORRECT ANSWERS Pair of chromosomes that carry genes for the same characteristics, at the same gene loci. Homozygous - CORRECT ANSWERS When an organism carries two copies of the same alleles. Heterozygous - CORRECT ANSWERS When an organism has two different alleles of the same gene.

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Genotype - CORRECT ANSWERS Description of an organism's alleles. Autosome - CORRECT ANSWERS Any chromosome that is NOT a sex chromosome. Autosomal linkage - CORRECT ANSWERS Genes coding for different characteristics, found on the same non-sex chromosome, are said to be linked. Independent assortment - CORRECT ANSWERS During metaphase I of meiosis, the arrangement of one pair of homologous chromosomes on the equator of the spindle is independent of the arrangement of any other pair of chromosomes. A key event that produces GENETIC VARIATION in gametes. Crossing over - CORRECT ANSWERS Where chromatids twist around each other and exchange genetic material. Happens during prophase I of meiosis which increases the amount of GENETIC VARIATION in gametes by producing new combination of alleles. Carrier - CORRECT ANSWERS Individual who has an allele, often for a disease, which is not expressed in the phenotype i.e. they are heterozygous. True breeding - CORRECT ANSWERS Individuals that are true breeding are homozygous for a particular characteristic or trait. Epistasis - CORRECT ANSWERS A type of gene interaction, where the allele of one gene masks the effect of the allele of a different gene. Hemizygous - CORRECT ANSWERS Having a single copy of a gene instead of the normal two. For example, if there is heterozygous inheritance of the sex chromosomes, XY. Variation - CORRECT ANSWERS The range of differences in characteristics between organisms Phencopy - CORRECT ANSWERS When environmental conditions alter the phenotype to resemble the effects of genotypic change

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Discontinuous variation - CORRECT ANSWERS Variation where there are 2 or more distinct categories with no intermediates. Determined by a small number of genes with little or no environmental influence. Continuous variation - CORRECT ANSWERS Variation where there are two extremes and all possible intermediate forms. Determined by many genes (polygenic) and influenced by the environment. Etiolation - CORRECT ANSWERS When plants grow abnormally long and spindly because they are not getting enough light. Chlorosis - CORRECT ANSWERS When plants don't produce enough chlorophyll and turn yellow eg due to lack of magnesium in the soil. Artificial selection - CORRECT ANSWERS When humans select which individuals in a population to breed together in order to get desirable traits. Stabilising selection pressure - CORRECT ANSWERS Factor that reduces the range of phenotypes by selecting against individuals with the extreme phenotype. Selection pressure - CORRECT ANSWERS A factor that gives a greater chance of surviving to some members of the population than others e.g. moth camouflage Stabilising selection - CORRECT ANSWERS Types of selection that operates against the extremes of the range of phenotypes so the population remains the same over time. Directional selection - CORRECT ANSWERS Factor that selects individuals with an extreme phenotype of a range of phenotypes so the population changes over time. Genetic drift - CORRECT ANSWERS The increase or decrease in the frequency of alleles as a result of chance events.

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Carrying capacity - CORRECT ANSWERS The maximum population size of a species that a particular habitat can support over time. Gene pool - CORRECT ANSWERS The sum of all the alleles in a population at a given time. Genetic bottleneck - CORRECT ANSWERS An event, such as a natural disaster, that causes a large reduction in the size of a population. Founder effect - CORRECT ANSWERS What happens when a small number of individuals start a new population and there is only a small number of alleles. Species - CORRECT ANSWERS A group of similar organisms that can reproduce to give fertile offspring. Allopatric speciation - CORRECT ANSWERS Populations become geographically isolated and, as a result of natural selection, form new species. Sympatric speciation - CORRECT ANSWERS Formation of a new species without geographical isolation. Reproductive isolation - CORRECT ANSWERS Populations cannot breed successfully together because of mechanical changes or behavioral changes. Geographical isolation - CORRECT ANSWERS A physical barrier such as a mountain range or a desert that prevents gene flow between populations. Natural selection - CORRECT ANSWERS The mechanism of evolution.It is the survival of individuals in a population to reproduce and pass on their alleles to the next generation. Restriction endonuclease - CORRECT ANSWERS Enzyme that cuts DNA molecules at a specific sequence of bases.

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Palindromic recognition site - CORRECT ANSWERS The specific sequence of bases where a restriction enzyme will cut. The sequence of bases reads the same in opposite directions. DNA ligase - CORRECT ANSWERS Enzyme which joins sections of DNA together, catalysing condensation reaction. Sticky ends - CORRECT ANSWERS When a restriction endonuclease cuts DNA and leaves unpaired bases. Vector DNA - CORRECT ANSWERS Used to transfer DNA into a cell eg a plasmid or bacteriophage. Plasmid - CORRECT ANSWERS Small, circular molecule of DNA used to transfer DNA into cells. Bacteriophage - CORRECT ANSWERS A virus that infects a bacterium and can be used as a DNA vector. Electroporation - CORRECT ANSWERS An electric field used to increase the permeability of a bacterial cell membrane so that it takes up plasmids more readily. Agrobacterium tumefaciens - CORRECT ANSWERS A bacterium used to introduce genes into a plant cell in order to produce genetically modified plants. Technology transfer - CORRECT ANSWERS The sharing of knowledge, skills and technology. Somatic gene therapy - CORRECT ANSWERS Altering the alleles in body cells in order to treat a genetic disorder. Germ line gene therapy - CORRECT ANSWERS Altering the alleles in sex cells/zygotes. (Currently illegal in humans)

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Polymerase Chain Reaction - CORRECT ANSWERS Technique used to (amplify) copy fragments of DNA millions of times in just a few hours. (Also called in vitro cloning.) Thermostable DNA polymerase - CORRECT ANSWERS Enzyme used to copy DNA in PCR which is not denatured by high temperatures. Primer - CORRECT ANSWERS Short section of single stranded DNA which binds to DNA in PCR and acts as a binding site for DNA polymerase and initiates copying of the DNA. Electrophoresis - CORRECT ANSWERS Technique that uses an electric field to separate DNA fragments, RNA fragments or proteins, based on their size (and in the case or proteins the charges on the R groups.) Southern blotting - CORRECT ANSWERS Technique that transfers DNA fragments from agarose gel to a nylon membrane after electrophoresis DNA probe - CORRECT ANSWERS Short section of single stranded DNA used to bind to a complementary sequence of bases. Used to identify specific sections of DNA, following electrophoresis and Southern blotting. DNA hybridisation - CORRECT ANSWERS When probes hydrogen bind to DNA fragments, provided that they have a complementary sequence of bases. DNA profile - CORRECT ANSWERS A unique gel produced by DNA electrophoresis that shows the number of times repetitive, non-coding bases sequences are repeated at different loci in an individual. Variable number tandem repeats (VNTRs) or Minisatellites - CORRECT ANSWERS Sections of non-coding DNA base sequences that are repeated at different loci and used in DNA profiling. Genetic screening - CORRECT ANSWERS A technique that uses electrophoresis and probes to identify, for example, whether individuals are carriers of genetic disorders.

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Preimplantation genetic haplotyping (PGH) - CORRECT ANSWERS DNA sequencing - CORRECT ANSWERS The process of determining the order of nucleotides within a DNA molecule. Reverse transcriptase - CORRECT ANSWERS Enzyme that uses RNA as a template to make complementary DNA (cDNA) Marker gene - CORRECT ANSWERS Gene such as that for antibiotic resistance or green fluorescent protein used to identify transformed organisms. Genome - CORRECT ANSWERS The minimum quantity of DNA that contains one set of all the genes in an organism, including mitochondrial DNA and the DNA in the chloroplasts of plants. Recombination DNA - CORRECT ANSWERS DNA formed by joining together DNA from different sources eg a human gene in a bacterial plasmid. Transformed or Transgenic organisms - CORRECT ANSWERS Organisms that have been genetically engineered. Chain termination method - CORRECT ANSWERS Method of DNA sequencing that uses dideoxynucleotides. High-throughput sequencing - CORRECT ANSWERS A faster method of sequencing DNA eg using capillary flow electrophoresis. Next-generation sequencing - CORRECT ANSWERS Method of DNA sequencing that does not use chain termination method eg pyrosequencing. Synthetic biology - CORRECT ANSWERS Design of new biological systems and artificially made molecules using our knowledge of DNA and cell biology.

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Bioinformatics - CORRECT ANSWERS The use of computers, software, and mathematical models to process and integrate biological information from large data sets. Transcription Factors - CORRECT ANSWERS A protein that binds to DNA and switches a gene on or off by increasing or decreasing the rate of transcription Promoter - CORRECT ANSWERS A DNA sequence (located before the structural genes in an operon) that RNA polymerase binds to. Activator - CORRECT ANSWERS A transcription factor that increases the rate of transcription Repressor - CORRECT ANSWERS A transcription factor that decreases the rate of transcription Operon - CORRECT ANSWERS A section of DNA that contains structural genes that are all transcribed together, control elements and sometimes a regulatory gene. Regulatory gene - CORRECT ANSWERS A gene that gives rise to a transcription factor. Structural gene - CORRECT ANSWERS A gene that codes for a polypeptide (protein) The lac operon - CORRECT ANSWERS A gene in E.coli that codes for the production of enzymes that break down lactose. This gene is only turned on in the presence of lactose and is therefore self-regulating. Intron - CORRECT ANSWERS A section of DNA that doesn't code for an amino acid Exon - CORRECT ANSWERS A section of DNA that codes for amino acids Splicing - CORRECT ANSWERS The process that changes primary mRNA into mature mRNA by removing the introns and rejoining the exons together.

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cyclic AMP (cAMP) - CORRECT ANSWERS A molecule that activates proteins inside cells by altering their tertiary structures. Hox genes - CORRECT ANSWERS Genes that encode proteins which control body plan development Homeobox sequence - CORRECT ANSWERS A sequence in a homeotic gene that codes for the homeodomain. Homeodomain - CORRECT ANSWERS Part of a transcription regulatory protein that binds to DNA, allowing the protein to act as a transcription factor. Apoptosis - CORRECT ANSWERS A highly controlled process by which cells are broken down. part of programmed cell death. Mutation - CORRECT ANSWERS Any change in the DNA base (nucleotide) sequence Deletion mutation - CORRECT ANSWERS A mutation where one or more bases are removed and may result in a frame shift. Insertion mutation - CORRECT ANSWERS A mutation where one or more bases are inserted and may result in a frame shift Substitution mutation - CORRECT ANSWERS A mutation where one or more bases are replaced by another base. Frame shift mutation - CORRECT ANSWERS This occurs when a deletion or insertion mutation occurs in a gene. The number of bases in the entire sequence changes, causing a shift in all the base triplets that follow. Neutral mutation - CORRECT ANSWERS A mutation that does not affect the phenotype of the organism.

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Post Translation Level Control - CORRECT ANSWERS Modify the protein after it is made by chemical modification or cleavage Meristem - CORRECT ANSWERS an undifferentiated, growing region of a plant that is constantly undergoing cell division and differentiation Vegetative propagation - CORRECT ANSWERS A form of asexual reproduction in which plants produce genetically identical offshoots (clones) of themselves, which then develop into independent plants. Cloning - CORRECT ANSWERS Process that produces a group of genetically identical organisms. Micropropagation - CORRECT ANSWERS Using sterile plant tissue grown to form a callus culture from which many new plants are grown by separation and growth of small parts of the callus. Artificial embryo twinning - CORRECT ANSWERS Method of cloning animals by separating the individual cells of an early embryo to form a number of genetically identical embryos. Somatic cell nuclear transfer (SCNT) - CORRECT ANSWERS Involves removing the nucleus of an unfertilized egg cell, replacing it with the nucleus of a "somatic cell" (a skin, heart, or nerve cell, for example), and stimulating this cell to begin dividing. It is then implanted into a surrogate mother. Therapeutic cloning - CORRECT ANSWERS The cloning of human cells by nuclear transplantation for therapeutic purposes, such as the generation of embryonic stem cells to treat disease. Embryonic stem cell - CORRECT ANSWERS An undifferentiated cell, taken from an embryo that is able to undergo mitosis and has the potential to give rise to many various other cell or tissue types Non reproductive cloning - CORRECT ANSWERS Use of stem cells to generate replacement tissues and organs which may be used to treat disease

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reproductive cloning - CORRECT ANSWERS a method to clone an adult using nuclei from some of its somatic cell mitosis - CORRECT ANSWERS A type of cell division that results in two daughter cells that are genetically identical to the parent nucleus, typical of ordinary tissue growth. callus - CORRECT ANSWERS A mass of dividing, undifferentiated cells at the cut end of a shoot. tissue culture - CORRECT ANSWERS Using small groups of cells from a plant to make new plants. aseptic conditions - CORRECT ANSWERS Working in a manner which avoids introducing foreign bacteria into a pure culture, or contaminating either the environment or the experimenter. differentiation - CORRECT ANSWERS Process in which cells become specialized in structure and function plantlets - CORRECT ANSWERS some plants reproduce vegetatively by producing monozygotic twins - CORRECT ANSWERS identical twins genetically identical - CORRECT ANSWERS having the same exact genome ( DNA) Immobilised enzymes - CORRECT ANSWERS Enzymes that are attached or fixed to each other or to an inert material Batch culture - CORRECT ANSWERS The growth of bacteria in a closed system without inputs of nutrients.

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Continuous culture - CORRECT ANSWERS Culture of microorganisms set up in a reaction vessel to which substrates are added and from which products are removed as the fermentation process goes on Aseptic technique - CORRECT ANSWERS precautions taken to prevent contamination with unwanted microorganisms Primary metabolites - CORRECT ANSWERS Substances produced by an organism during normal growth; include amino acids, proteins, enzymes, etc. Primary metabolite production matches growth of population of organism. Secondary metabolites - CORRECT ANSWERS products are NOT necessary for microbial growth (antibiotics, steroids,etc) turbidity - CORRECT ANSWERS as bacteria multiply within a medium, the medium becomes cloudy with cells standard growth curve - CORRECT ANSWERS lag phase--> log phase--> stationary phase--> death phase (microbial growth) lag phase - CORRECT ANSWERS A short period of time **prior to exponential growth of a bacterial population during which no, or very limited, cell division occurs. log phase - CORRECT ANSWERS The period of exponential growth of bacterial population. stationary phase - CORRECT ANSWERS The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the decline phase - CORRECT ANSWERS The bacterial growth stage which involves a decrease in cell numbers as nutrients are used up is known as the ____ serial dilution - CORRECT ANSWERS Process of adding solvent (usually water) to solute using regular ratios or proportions in order to create a series of dilute solutions.

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viable count - CORRECT ANSWERS Counting all the living cells, and no dead ones usually through dilution plating. The density of live cells. biotechnology - CORRECT ANSWERS The manipulation of living organisms or their components to produce useful products. downstream processing - CORRECT ANSWERS Extraction, separation and purification of a product from a large scale process. bioremediation - CORRECT ANSWERS the use of organisms to remove toxic materials from the environment fermenter - CORRECT ANSWERS A vessel used to grow microorganisms in large numbers. intracellular enzymes - CORRECT ANSWERS Enzymes that catalyse reactions inside of the cell extracellular enzymes - CORRECT ANSWERS What term describes enzymes that microorganisms produce and release outside of the cell? Biotic factor - CORRECT ANSWERS A living factor that influences populations in an ecosystem Abiotic Factor - CORRECT ANSWERS A non living factor that influences populations. Ecosystem - CORRECT ANSWERS Habitat and community within a fixed area Biomass - CORRECT ANSWERS Mass of living material per unit area. Efficiency of biomass transfer - CORRECT ANSWERS Biomass of previous trophic level divided by biomass of current trophic level then x 100

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Saprobiotic nutrition - CORRECT ANSWERS Fungi and bacteria that produces enzymes within the cell which are then transported outside of the cell (extracellular) to digest biochemicals. They then absorb the products. Nitrogen fixation - CORRECT ANSWERS Taking nitrogen gas and incorporating it into a nitrogen compound. Rhizobium - CORRECT ANSWERS Found in root nodules. Fix nitrogen into ammonia. Azotobactor - CORRECT ANSWERS Free living Nitrogen fixing bacteria Ammonification - CORRECT ANSWERS Decomposition of proteins in dead organic matter to release ammonia. Nitrification - CORRECT ANSWERS Turning ammonia into nitrate. Nitrosomanas - CORRECT ANSWERS Bacteria involved in oxidation of ammonia into nitrites Nitrobacter - CORRECT ANSWERS Bacteria involved in the oxidation of Nitrites to nitrates. Denitrification - CORRECT ANSWERS Denitrifying bacteria convert nitrates into nitrogen gas ( anaerobic) Primary succession - CORRECT ANSWERS Sequence of plants colonizing a newly formed environment. e.g. on newly formed volcanic rock. Secondary succession - CORRECT ANSWERS If an environment has already undergone succession and an event e.g. tree fall removes the climax community and succession starts again - not necessarily from the beginning. Deflected succession - CORRECT ANSWERS Something prevents the process reaching climax community such as grazing. the result is a plagioclimax community.

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Taxonomic hierarchy - CORRECT ANSWERS Classification system based on large groups being subdivided in to smaller groups that do not overlap. Phylogeny - CORRECT ANSWERS The study of evolutionary relationships between organisms. Phylogenetic tree - CORRECT ANSWERS Diagram representing the evolutionary relationships of organisms with a common ancestor. Cladistics - CORRECT ANSWERS Classification system based on an organisms evolutionary history. Domain Bacteria - CORRECT ANSWERS A domain made up of prokaryotes. Contains the Kingdom Eubacteria. They lack a nucleus and membrane bound organelles. They have a single circular strand of DNA and small 70s ribosomes. Domain - CORRECT ANSWERS A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya. Domain Archaea - CORRECT ANSWERS Domain containing single-celled, simple organisms, genetically distinct from bacteria, often thriving in extreme environmental conditions. Domain Eukarya - CORRECT ANSWERS Domain of all organisms whose cells have membrane bound organelles including nuclei. The domain includes protists, plants, fungi, and animals. Kingdom - CORRECT ANSWERS Large taxonomic group, consisting of closely related phyla Kingdom Prokaryotae - CORRECT ANSWERS Bacteria (most recently divided into two kingdoms: Kingdom Eubacteria and Kingdom Archaebacteria/Archaea) Kingdom Protoctista - CORRECT ANSWERS Includes a diverse collection of single-celled and multicelled organisms that have a nucleus. Includes algae.

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Kingdom Fungi - CORRECT ANSWERS Heterotrophic organisms, they secrete enzymes and digest food outside of their bodies then absorb the nutrients, are multicellular, and have cell walls of chitin and often form mulitnucleate hypae. Kingdom Plantae - CORRECT ANSWERS Multicellular eukaryotes that photosynthesize (photoautotrophs) and have cell walls made of cellulose. Kingdom Animalia - CORRECT ANSWERS A kingdom a of multicellular, heterotrophic eukaryotic organismsins that are free-moving, lack cell walls Binomial nomenclature - CORRECT ANSWERS A system for giving each organism a two-word scientific name that consists of the genus name (initial letter written with a capital letter) followed by the species name (Lower case). Written in italics/underlined. Species - CORRECT ANSWERS A group of similar organisms that can breed and produce fertile offspring. Paleontology - CORRECT ANSWERS The study of fossils Comparative anatomy - CORRECT ANSWERS the study of similarities and differences in the anatomy of different species Homologous structures - CORRECT ANSWERS Features that are similar in structure but appear in different organisms and have different functions. Divergent evolution - CORRECT ANSWERS A form of evolution in which the same organism is placed into different environments with different selection pressures. This causes organisms to evolve differently, to diverge from their common ancestor. The resulting (new) species may share structural (but not necessarily functional) similarity; divergent evolution produces homologous structures. Convergent evolution - CORRECT ANSWERS Process by which unrelated organisms independently evolve similarities when adapting to similar environments.

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Comparative biochemistry - CORRECT ANSWERS Comparison of organisms proteins/DNA. If amino acid/nucleotide sequence is similar then the organisms are related. Comparative embryology - CORRECT ANSWERS Among different species, there are similarities in embryo appearance and anatomy. This concept supports the theory of evolution. Inter-specific variation - CORRECT ANSWERS Variation between members of different species Intra-specific variation - CORRECT ANSWERS Variation between members within the same species Discontinuous variation - CORRECT ANSWERS Variation between living organisms within a species, where there are discrete categories and no intermediates, e.g. blood groups A, B, AB or O in humans. This type of variation is determined by one gene. Continuous variation - CORRECT ANSWERS Variation between living organisms where there is a range of intermediates, such as height, hair colour and intelligence in humans. These characteristics are determined by many genes that interact. The expression of these genes is also influenced by the environment. Genotype - CORRECT ANSWERS An organism's genetic makeup, or allele combinations. Phenotype - CORRECT ANSWERS An organisms physical appearance or visible traits Allele - CORRECT ANSWERS Alternative versions of a gene that produce distinguishable phenotypic effects. Evolution - CORRECT ANSWERS A change in a species over time, the process by which modern organisms have descended from ancient organisms. Mutation - CORRECT ANSWERS Any change in the nucleotide sequence of DNA

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Natural selection - CORRECT ANSWERS A process in which individuals that have certain alleles/inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Reproductive success - CORRECT ANSWERS The likelihood of an individual contributing fertile offspring to the next generation. Standard deviation - CORRECT ANSWERS A measure of the spread of data around the mean. A measure of the variability in the data. Pathogen - CORRECT ANSWERS An organism that causes disease Antigen - CORRECT ANSWERS A molecule that triggers the immune response Antibody - CORRECT ANSWERS Plasma proteins with specific antigen -binding sites,constant and hinge regions Interleukins - CORRECT ANSWERS proteins (cytokines) that stimulate the growth of B and T lymphocytes Plasma cells - CORRECT ANSWERS Cells that develop from B cells and produce antibodies. Clonal selection - CORRECT ANSWERS the process during the immune responses when specific B cells /T cells interact with antigens displayed by APC Clonal expansion - CORRECT ANSWERS Mitotic division of a small group of identical cells after clonal selection. Cells differentiate into memory /plasma cells Phagocytosis - CORRECT ANSWERS process in which neutrophils and macrophages engulf and digest microorganisms and cellular debris. Third line of defence - CORRECT ANSWERS A response to invading specific pathogens involving lymphocytes and antibodies

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Callose - CORRECT ANSWERS A polysaccharide made by plant cells in defence against attack by pests and pathogens Communicable disease - CORRECT ANSWERS Diseases caused by a pathogen that can be transmitted from one host organism to another Vector - CORRECT ANSWERS An organism that transfers a pathogen from an infected host to an uninfected host. First line of defence - CORRECT ANSWERS Physical and chemical defences that prevent entry of pathogens Inflammation - CORRECT ANSWERS a reaction to injury or infection.Excess tissue fluid forms (swollen). Histamines are released and arterioles dilate ( red). Phagocytes squeeze out of capillaries and engulf pathogens( hot ) Cytokines - CORRECT ANSWERS Small protein molecules that act as cell-signalling molecules Plasma cell - CORRECT ANSWERS An activated B cell that makes and releases antibodies during an immune response T helper cell - CORRECT ANSWERS Type of lymphocyte that coordinates the immune response using chemical signals such as interleukins Agglutination - CORRECT ANSWERS The clumping together of pathogens using antibodies Opsonisation - CORRECT ANSWERS the marking of pathogens by antibodies to facilitate phagoctosis Antibiotics - CORRECT ANSWERS Any substance produced by a microorganism that can harm or kill another microorganisms

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Autoimmune disease - CORRECT ANSWERS A disease in which the immune system attacks the organisms own cells antibiotic resistance - CORRECT ANSWERS Resistance evolving rapidly in many species of prokaryotes due to overuse of antibiotics, especially in agriculture. Neutralisation - CORRECT ANSWERS Antibodies - Main role = Blood clotting - CORRECT ANSWERS platelets,cells and fibres form a mesh at a cut preventing blood loss and entry of pathogens. Scab forms Expulsive reflex - CORRECT ANSWERS sneezing,coughing,vomiting antigen presenting cell - CORRECT ANSWERS these are cells that recognizes antigens and brings them into the cell by phagocytosis; the cells then breaks up the antigen and present them on the cell surface membrane plasmodesma - CORRECT ANSWERS A microscopic channel through plant cell walls, connecting the cytoplasm of two cells. These are lined with plasma membrane. (pl: plasmodesmata) Accuracy - CORRECT ANSWERS How close a measurement is to the true value. However, the true value may not be known Anomaly - CORRECT ANSWERS All results show variation. This describes a result that lies beyond this variation. Confidence - CORRECT ANSWERS Is a qualitative judgement expressing the extent to which a conclusion is justified by the quality of the evidence. Error (of measurement) - CORRECT ANSWERS The Difference between the recorded value and the true value.

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Precision - CORRECT ANSWERS The closeness of agreement between independent measurements obtained under the same conditions. It depends only on the distribution of random errors (i.e. the spread of measurements) and does not relate to the true value. Repeatability - CORRECT ANSWERS The precision obtained when measurement results are produced over a short timescale by one person using the same equipment in the same place. Reproducibility - CORRECT ANSWERS Is the precision obtained when measurement results are produced over a wider timescale by different people using equivalent equipment in different places. Resolution - CORRECT ANSWERS Is the smallest change in the quantity being measured that can be detected by an instrument. Uncertainty - CORRECT ANSWERS An estimate as to where the true value actually lies. This is normally expressed as a range of values such as 44.0 ± 0.4. Validity - CORRECT ANSWERS A description of a measurement of whole investigation to explain if it measures what it set out to measure. i.e. confounding variables have not significantly affected the result and it has been referenced to a control experiment. Bar chart - CORRECT ANSWERS A graph used to display discontinuous discrete data e.g. blood group. The bars do not touch Line graph - CORRECT ANSWERS A graph used to display continuous data e.g. height. Scatter graph - CORRECT ANSWERS A graph used to display the relationship between two sets of continuous data e.g. width and length of leaves Histogram - CORRECT ANSWERS A graph used to display frequency of continuous data in certain groups. The size of the bar is proportional to the data in that group. The bars touch to show it is continuous data.

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Continuous - CORRECT ANSWERS Data that can be any value within a range e.g. foot length in mm Discontinuous (discrete) - CORRECT ANSWERS Data that is clearly define into groups e.g. shoe size Species - CORRECT ANSWERS A group of organisms of common ancestry that interbreed to give rise to fertile offspring. Biodiversity - CORRECT ANSWERS The number of different ecosystems and habitats in an area, the number of species within those ecosystems and the genetic variation within each species. Species diversity - CORRECT ANSWERS The number of different species within a defined an ecosystem or defined area. Habitat diversity - CORRECT ANSWERS The number of different ecosystems and habitats within a defined area. Genetic diversity - CORRECT ANSWERS The genetic variation within a species or population. Monomorphic gene - CORRECT ANSWERS A gene with no alleles. Polymorphic gene - CORRECT ANSWERS A gene with 2 or more tpes of allele. Allele - CORRECT ANSWERS Different forms of the same gene. Gene pool - CORRECT ANSWERS All of the alleles of all the genes in one species. locus - CORRECT ANSWERS The position a gene occupies on a chromosome (pl: loci) Species richness - CORRECT ANSWERS The number of species present in an area.

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Species evenness - CORRECT ANSWERS A measure of the relative abundance of the different species in an area. Random sampling - CORRECT ANSWERS Sampling an area with an unbiased method. Simpson's index of diversity - CORRECT ANSWERS A calculation of species diversity that takes into account species richness and species evenness. Opportunistic sampling. - CORRECT ANSWERS Choosing samples with a biased method e.g. based on how easy or safe the sample area is. Stratified sampling - CORRECT ANSWERS Choosing samples that will proportionately represent the sample area, usually used when there is more than one habitat. Systematic sampling - CORRECT ANSWERS Choosing samples that will transect a given area so as to not miss any areas out along that transect. Usually used for showing a gradual change along a habitat. Kite diagram - CORRECT ANSWERS A graph that is sometimes used to represent the data of a belt or line transect. Habitat fragmentation - CORRECT ANSWERS A type of habitat loss where a habitat is divided into smaller areas, this can result in populations being separated from each other. Overexploitation - CORRECT ANSWERS The over use of natural resources such as deforestation of hard wood trees that take decades to regrow. Unsustainable harvesting of resources. Monoculture - CORRECT ANSWERS Growing the same crop (or farming the same species of livestock) over a large area for several years. Reduces species and habitat diversity. Eutrophication - CORRECT ANSWERS When fertilisers cause water pollution.

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Keystone species - CORRECT ANSWERS A species that contributes more to an ecosystem than it's size or number may suggest. These are usually apex predators at the top of the food web. Flagship species - CORRECT ANSWERS A species that boosts ecotourism for a particular area. People will travel especially to see it in the wild e.g. elephants in Africa or Giant Panda's in China. In situ conservation - CORRECT ANSWERS The protection and maintenance of an area so that species can continue to live in their original habitat. UNESCO - CORRECT ANSWERS United Nations Educational, Scientific and Cultural Organisation Ex situ conservation - CORRECT ANSWERS Removal of a species to a protected place that is not its normal habitat. Seed bank - CORRECT ANSWERS A long term store of germplasm in the form of seeds. Collections of seeds are dried and then stored at temperatures near -20C CBD - CORRECT ANSWERS Convention of Biological Diversity (1992/3) CITES - CORRECT ANSWERS Convention on International Trade in Endangered Species (of Wild Fauna and Flora) 1975. Tissue - CORRECT ANSWERS A group of cells (plus any extracellular material they secrete) that are specialised to work together to carry out a particular function. Organ - CORRECT ANSWERS A group of different tissues that work together to carry out a particular function. Organ system - CORRECT ANSWERS A group of organs that work together to carry out a particular function.

UPDATED 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED

BEST EXAM SOLUTION TOP RANKED TO SCORE A+

Totipotent - CORRECT ANSWERS These cells are unspecialised and are able to divide and give rise to any type of body cell. They include the zygote and the very early embryo. Pluripotent - CORRECT ANSWERS These cells (embryonic stem cells) are unspecialised and are able to divide and give rise to any type of body cell but not the extra-embryonic membranes. Multipotent - CORRECT ANSWERS These cells (adult stem cells) can divide and give rise to a small number of cell types. Stem cells - CORRECT ANSWERS Cells that are able to divide and give rise to a number of different cell types. They may be pluripotent (embryonic stem cells) or multipotent (adult stem cells). Differentiation - CORRECT ANSWERS Process by which unspecialised cells become specialised and adapted for their particular function by the switching on and off of different genes. Meristem - CORRECT ANSWERS That part of plant where mitosis takes place and plants grow. Cambium - CORRECT ANSWERS The meristematic cells that divide to produce new xylem and phloem when a plant increases in girth. All tests. - CORRECT ANSWERS Add sample to a test tube and crush with a stirring rod. Proteins - CORRECT ANSWERS Add sodium hydroxide. Trickle dilute copper sulphate down the wall of the test tube. A positive result is from blue to purple. Lipids - CORRECT ANSWERS Add ethanol. Mix well. Decant supernatant into a test tube of water. The water will turn from clear to a milky white emulsion for a positive result. Starch - CORRECT ANSWERS Add iodine. Colour changes from brown to deep blue/black.