BioTWA2Glossary 100 A-G

  1. Abiotic condition
    A non-living feature of an ecosystem
  2. Abundance
    The number of individuals of one species in a particular area (i.e. population size)
  3. Accurate result
    A result that is really close to the true answer
  4. Acetylation
    Attachment of an acetyl group to something (e.g. histones)
  5. Acetylcholine (ACh)
    A type of neurotransmitter that binds to cholinergic receptors
  6. Acetyl coenzyme A (Acetyl CoA)
    A type of coenzyme involved in respiration. It transfers acetate from one molecule to another.
  7. Acquired Mutation
    A mutation developed during life.
  8. Actin
    The thin myofilament protein in muscle fibres.
  9. Actin-myosin cross bridge.
    The bond formed when a myosin head binds to an actin filament.
  10. Activator
    A transription factor that increases the rate of transcription.
  11. Active Transport
    Movement of molecules and ions across plasma membranes usually against a concentration gradient. Requires energy.
  12. Adaptation
    A feature that increases an individual's chance of survival and reproduction.
  13. ADP (Adenosine diphosphate)
    A molecule made up of adenine a ribose sugar and two phosphate groups. A nucleotide derivative. ADP becomes ATP when it is phosphorylated.
  14. Adrenaline
    A hormone secreted from the adrenal glands that has many effects - including increasing blood glucose concentration.
  15. Allele
    A specific version of a gene (blood group, eye colour etc.)
  16. Allele Frequency
    How often and allele crops up in a population.
  17. Allopatric speciation
    Speciation caused by geographic separation.
  18. Ammonification
    The process by which nitrogen compounds from dead organisms or waste material are turned into ammonium compounds by saprobionts.
  19. Anomalous result
    A measurement that falls outside of the range of values you expected, based on the pattern of results you have seen.
  20. Antidiuretic hormone (ADH)
    A hormone that regulates the water potential of the blood by controlling the permeability of the cells of the distal convoluted tubule and the collecting duct of the kidney.
  21. ATP (Adenosine triphosphate)
    A molecule made up of adenine and ribose sugar (a nucleotide derivative) with three phosphates attached. The source of energy in the cell.
  22. ATP hydrolase
    Enzyme catalyses breakdown ATP-ADP + Pi
  23. ATP-Phosphocreatine system
    A system that generates ATP very quickly by phosphorylating ADP using a phosphate group from phosphocreatine.
  24. ATP Synthase
    An enzyme that generates ATP from ADP + Pi (usually during respiration).
  25. Atrioventricular Node (AVN)
    A group of cells in the heart wall that is responsible for passing waves of electrical impulses from the SAN to theĀ  bundle of His.
  26. Autonomic nervous system
    A division of the peripheral nervous system that controls unconscious activities - such as heart rate.
  27. Autosomal linkage
    When two genes are located on the same autosome and are inherited together.
  28. Autosome
    Non-sex chromosome.
  29. Benign tumour
    A non-cancerous tumour (growth)
  30. Bias
    When someone intentionally (or not) favours a particular result.
  31. Biomass
    The mass of living material in an organism/population/ecosystem.
  32. Biotic condition
    A living feature of an ecosystem (competition, availability of prey, predators, potential reproductive partners or any other biotic interaction).
  33. Bundle of His
    A group of muscle fibres in the heart responsible for conducting waves of electrical impulses from the AVN to the Purkyne fibres.
  34. Cardiomyocyte
    A heart muscle cell.
  35. Carrier
    A person carrying an allele that is no expressed in their phenotype, but can still be passed on.
  36. Carrying Capacity
    The maximum stable population size of a species that an ecosystem can support.
  37. Causal relationship
    Where a change in one variable causes a change in the other.
  38. cDNA (complementary DNA)
    A DNA copy of mRNA made using reverse transcriptase.
  39. Chemical mediator
    A chemical messenger that acts locally (i.e. on nearby cells).
  40. Chemiosmosis
    The process of electrons flowing down the electron transport chain and creating a proton gradient across a membrane to drive ATP synthesis.
  41. Chlorophyll
    A photosynthetic pigment found in Chloroplasts. There are different types of this pigment - given letters (a, b).
  42. Choice chamber
    A container with different compartments that can be used to investigate how animals respond to different environmental conditions.
  43. Cholinergic synapse
    A synapse that uses the neurotransmitter acetylcholine.
  44. Climax community
    The final stage in succession - for example Oak Woodland in Western Europe, or Tropical hardwood forest in central America. The point at which carrying capacity is all used up.
  45. Codominant allele
    An allele whose character together with another allele in the phenotype because neither is recessive.
  46. Codon
    3 nucleotides = 1 amino acid.
  47. Coenzyme
    A molecule that aids the function of an enzyme. They work by transferring one chemical group to another.
  48. Community
    All the populations of different species in a habitat.
  49. Compensation point
    The point at which the rate of photosynthesis in a plant exactly matches matches its rate of respiration.
  50. Cone (eye)
    A photoreceptor cell found in the eye that is colour sensitive.
  51. Conservation
    The protection and management of species and habitats in a sustainable way.
  52. Continuous data
    Data that can take any value in the range (height, mass, age) as opposed to things such as handedness, or blood type.
  53. Control group
    A group in a study that is treated in exactly the same way as the experimental group apart from the factor you are investigating.
  54. Control variable
    A variable which is kept the same each time an experiment is repeated.
  55. Coordinator (nervous)
    Part of the nervous system (CNS etc.) which formulates the response to a stimulus before sending impulses to an effector.
  56. Correlation
    A relationship between two variables.
  57. Dehydrogenase
    An enzyme that transfers hydrogen and electrons from one molecule to another.
  58. Denitrification
    The process by which nitrates in the soil are converted into nitrogen gas by denitrifying bacteria.
  59. Dependent variable
    The variable you measure in an experiment.
  60. Depolarisation
    A decrease in the potential difference across a cell's membrane making it less negative (i.e. more positive) than the resting potential.
  61. Diabetes mellitus (type 1)
    A condition in which blood glucose concentration can't be controlled properly because the body doesn't produce insulin.
  62. Diabetes mellitus (type 2)
    A condition in which blood glucose concentration can't be controlled because the body doesn't produce enough insulin or cells don't respond to insulin in the blood.
  63. Dihybrid inheritance
    The inheritance of two characters controlled by different genes. (dihybrid crosses etc)
  64. Directional selection
    Where individuals with alleles for a single extreme phenotype are more likely to survive and pass on genes - shifting the average towards those features over several generations.
  65. Discrete data
    Numerical data that can only take certain values in a range (number of limbs/leaves/eyes/elephants in a herd).
  66. Disruptive selection
    Where individuals with alleles for various extreme features at the limits of the phenotype are more likely to survive - possibly leading to sympatric speciation.
  67. Distribution
    The spread of a particular species across an area. Often associated with other factors - light, salinity, prey availability/presence of predators.
  68. DNA polymerase
    An enzyme that joins together the nucleotides on a new strand of DNA after complementary base pairing has linked them to the original template strand.
  69. DNA Probe
    A short single strand of DNA that has a base sequence complementary to a target gene.
  70. DNA Sequencing
    A technique used to determine the order of bases in a sequence of DNA.
  71. Dominant allele
    An allele who characteristic appears in the phenotype whenever it is present.
  72. Ecosystem
    All the living and non living aspects of a habitat.
  73. Effector
    Does things - muscles/glands (usually)
  74. Electrochemical gradient
    A concentration gradient of ions.
  75. Electron transport chain
    A chain of proteins down which excited electrons flow.
  76. Epigenetic control of gene expression
    The attachment and removal of chemical groups to DNA/histones which determines whether genes are 'switched on' or 'switched off'.
  77. Epistasis
    When the expression of an allele masks the expression of others. For example. A man with a widows peak (an allele for this exists) would not express it if he also had the allele for baldness - the first allele would be rendered invisible.
  78. Evolution
    The change in the allele frequency in a population over time.
  79. Exocytosis
    The process whereby a cell secretes/excretes substances using vesicles.
  80. Exon
    The part of DNA that codes for amino acids
  81. Extracellular digestion
    When food is broken down using enzymes outside the cell, and absorbed. Saprobionts use extracelluar digestion.
  82. Facilitated diffusion
    The diffusion of particles through the cell membrane using carrier proteins or protein channels.
  83. FAD
    A coenzyme involved in respiration. It transfers hydrogen from one molecule to another.
  84. Fast twitch (muscle fibre)
    A muscle fibre that contracts very quickly - but also gets tired very quickly.
  85. Frameshift mutation
    A mutation caused by a deletion or addition (which changes the number of bases in the genome). This shifts all the triplets which come after it - meaning they are read differently.
  86. Gel electrophoresis
    A technique that allows DNA fragments to be separated on a gel plate according to size (using electric current to move the fragments).
  87. Gene
    A section of DNA that codes for a protein and results in a characteristic.
  88. Gene Expression
    The transcription of a gene into mRNA and translation of the gene into a protein.
  89. Gene Pool
    The complete range of alleles present in a population.
  90. Generator potential
    The change in potential difference across a cell membrane due to a stimulus (in sensory receptor cells usually).
  91. Gene technology
    Techniques that allow the study of genes and alteration of their functions.
  92. Gene Therapy
    Altering genes inside cells to treat cancer or genetic illnesses.
  93. Genetic code
    The sequence of codons in a nucleic acid (DNA/mRNA) that codes for amino acids.
  94. Genetic disorder
    An inherited disorder caused by an abnormal gene or chromosome.
  95. Genetic drift
    The process whereby an allele changes in frequency in a population due to chance.
  96. Genetic engineering
    AKA recombinant DNA technology. When DNA from different organisms is joined together by isolating a fragment from a donor organism and inserting it into the DNA of a host.
  97. Genetic fingerprint
    A DNA gel that shows the number of times repetitive non-coding base sequences occur at different loci in an individual.
  98. Genetic pedigree diagram
    A diagram that shows how an inherited characteristic runs through a group of related individuals.
  99. Genome
    All the genetic material in an organism.
  100. Genotype
    The genetic constitution of an organism (the specific alleles of an individual). So a Brown eyed person may have a Bb genotype or a BB genotype.
Card Set
BioTWA2Glossary 100 A-G