These are all the definitions you need to know for the Biology HL IB Diploma final exam (syllabus of 2009) - class of 2015 only
Luisa Mandacaru
Flashcards by Luisa Mandacaru, updated more than 1 year ago
Luisa Mandacaru
Created by Luisa Mandacaru almost 9 years ago

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Question Answer
Define DIFFUSION Diffusion is the passive movement of particles from a region of high concentration to a region of low concentration.
Define OSMOSIS Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.
3.1.1 State the most frequently occurring chemical elements in living things Carbon, hydrogen, oxygen and nitrogen COHN
3.1.2 State the variety of other elements that are needed by living organisms Sulfur, calcium, phosphorus, iron and sodium. CPISS
Role of Sulphur Needed for the synthesis of two amino acids.
Role of Calcium Structure of bone and teeth Muscle contraction Transmission of nerve impulses
Phosphorus Is part of DNA molecules and is also part of the phosphate groups in ATP.
Role of iron Component of haemoglobin
Role of sodium Transmission of nerve impulses
Define ENZYMES Globular proteins which act as catalysts of chemical reactions.
Define ACTIVE SITE Region on the surface of an enzyme to which substrates bind and which catalyses a chemical reaction involving the substrates.
Define DENATURATION Denaturation is changing the structure of an enzyme (or other protein) so it can no longer carry out its function.
Define CELL RESPIRATION Cell respiration is the controlled release of energy from organic compounds in cells to form ATP.
Define GENES a heritable factor that controls a specific characteristic.
Define ALLELE One specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene
Define GENOME the whole of the genetic information of an organism.
Define GENE MUTATION a change to the base sequence of a gene.
Define HOMOLOGOUS CHROMOSOMES chromosomes with the same genes as each other, in the same sequence but do not necessarily have the same allele of those genes.
In karyotyping, chromosomes are arranged in pairs according to: to their size and structure.
Genotype definition the alleles of an organism.
PHENOTYPE the characteristics of an organism.
Dominant allele DEFINITION an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state.
Recessive Allele an allele that only has an effect on the phenotype when present in the homozygous state.
Codominant alleles: pairs of alleles that both affect the phenotype when present in a heterozygote.
Locus the particular position on homologous chromosomes of a gene
Homozygous: having two identical alleles of a gene.
Heterozygous: having two different alleles of a gene.
Carrier: an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele.
Test cross: testing a suspected heterozygote by crossing it with a known homozygous recessive
SEX LINKAGE when the gene controlling the characteristic is located on the sex chromosome and so we associate the characteristic with gender
CLONE a group of genetically identical organisms or a group of genetically identical cells derived from a single parent cell
SPECIES a group of organisms that can interbreed and produce fertile offspring.
HABITAT the environment in which a species normally lives or the location of a living organism.
POPULATION a group of organisms of the same species who live in the same area at the same time
COMMUNITY a group of populations living and interacting with each other in an area
ECOSYSTEM a community and its abiotic environment
ECOLOGY a community and its abiotic environment
AUTOTROPHS organisms that synthesize their organic molecules from simple inorganic substances
HETEROTROPHS heterotrophs are organisms that obtain organic molecules from other organisms.
CONSUMER an organism that ingests other organic matter that is living or recently killed.
DETRITIVORE an organism that ingests non-living organic matter.
SAPROTROPH an organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion.
TROPHIC LEVEL the trophic level of an organism is its position in the food chain
3 FACTORS THAT LIMIT POPULATION INCREASE - Shortage of resources (e.g. food) - Increase in predators - Increase in diseases and parasites
EVOLUTION Evolution is the cumulative change in the heritable characteristics of a population
PORIFERA - FEATURES - no clear symmetry - attached to a surface - pores through body - no mouth or anus - example: sponges
CNIDARIA - FEATURES Radially symmetric tentacles stinging cells mouth but no anus example: jellyfish
PLATYHELMINTHS - FEATURES bilaterally symmetrical flat bodies unsegmented mouth but no anus example: tapeworm
ANNELIDA - FEATURES bilaterally symmetrical bristles often present segmented mouth and anus example: earthworm
MOLLUSCA - FEATURES muscular foot and mantle shell may be present segmentation not visible mouth and anus example: slugs and snails
ARTHROPODA - FEATURES bilaterally symmetric exoskeleton segmented jointed appendages example: spiders and insects
Enzyme, Source, Substrate, Products and pH of PROTEASE Enzyme: PEPSIN Source: STOMACH Substrate: PROTEINS Products: POLYPEPTIDES pH: 2
Enzyme, Source, Substrate, Products and pH of LIPASE Enzyme: LIPASE Source: PANCREAS Substrate: TRIGLYCERIDES Products: FATTY ACIDS pH: 7
BLOOD COMPOSITION plasma, erythrocytes, leukocytes (phagocytes and lymphocytes) and platelets
TRANSPORTED BY BLOOD nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
PATHOGEN an organism or virus that causes a disease
RESTING POTENTIAL the electrical potential across the plasma membrane of a cell that is not conducting an impulse
ACTION POTENTIAL the reversal and restoration of the electrical potential across the plasma membrane of a cell, as an electrical impulse passes along it (depolarization and repolarization)
NUCLEOSOMES Nucleosomes consist of DNA wrapped around eight histone proteins and held together by another histone protein.
4 STEPS OF TRANSLATION initiation, elongation, translocation and termination 5 TO 3 DIRECTION
WAYS IN WHICH MINERAL IONS IN THE SOIL MOVE TO THE ROOT - fungal hyphae (mutualism) - mass flow of water in the soil - diffusion of mineral ions
DEFINE TRANSPIRATION Transpiration is the loss of water vapour from the leaves and stems of plants.
POLLINATION The process of pollen transfer from an anther to a stigma
FERTILIZATION The fusion of a male gamete with a female gamete inside the ovule. This forms a zygote.
SEED DISPERSAL The fusion of a male gamete with a female gamete inside the ovule. This forms a zygote.
LINKAGE GROUP A pair or set of genes on a chromosome which tend to be inherited together
POLYGENIC INHERITANCE when a particular phenotype is determined by more than one gene
IMMUNITY having sufficient biological defenses against infection
ACTIVE IMMUNITY immunity due to the production of antibodies by the organism itself after the body’s defence mechanisms have been stimulated by antigens
PASSIVE IMMUNITY is immunity due to the acquisition of antibodies from another organism in which active immunity has been stimulated, including via the placenta, colostrum, or by injection of antibodies
MUSCLES facilitate the movement of limbs and work in antagonistic pairs
LIGAMENTS hold joints together; they link one bone to another.
TENDONS muscles to bones so that muscle contraction causes movement
NERVES the structures that allow the CNS to control muscles and cause contraction
EXCRETION is the removal from the body of the waste products of metabolism AND consists of ultrafiltration followed by selective reabsorption
OSMOREGULATION is the control of the water balance of the blood, tissue or cytoplasm of a living organism is largely due to the effects of ADH on the collecting ducts and the action of the loop of Henle
OPTION D - EVOLUTION ALLELE FREQUENCY is the frequency of an allele, as a proportion of all alleles of the gene in the population
OPTION D - EVOLUTION GENE POOL All the genes in a interbreeding population
OPTION D - EVOLUTION HALF-LIFE The time it takes for the radioactivity to fall to half of its original level
OPTION D - EVOLUTION CLADISTICS is a method of classification of living organisms based on the construction and analysis of cladograms
OPTION D - EVOLUTION CLADE is a group of organisms that evolved from a common ancestor
OPTION G - ECOLOGY AND CONSERVATION BIOMASS Is the total dry mass of organic matter in organisms or ecosystems
OPTION G - ECOLOGY AND CONSERVATION GROSS PRODUCTION the total amount of organic matter produced by plants in an ecosysytem
OPTION G - ECOLOGY AND CONSERVATION NET PRODUCTION is the amount of gross production in an ecosystem remaining after subtracting the amount used by plants in respiration
OPTION G - ECOLOGY AND CONSERVATION BIOMAGNIFICATION is the process by which chemical substances become more concentrated at each trophic level
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