Studied by 21 people3' poly-A tail
a chain of adenine nucleotides added to the 3' end of pre-mRNA during RNA processing
5' methyl-G cap
a molecule added to the 5' end of pre-mRNA during RNA processing
absolute age
an estimate of the age (in years) of a fossil or rock
absolute dating
a dating technique used to determine the absolute age of a fossil by measuring the relative amounts of radioisotopes to their products. Also known as radiometric dating
accurate
how close a measurement is to the true value
acetyl-CoA
the product of the link reaction where pyruvate is conjugated to coenzyme A, creating the primary input into the Krebs cycle
activation energy
the energy required to initiate a reaction
active immunity
protection against a disease created by antibodies and memory cells formed by a person's own adaptive immune system
active site
the part of an enzyme where the substrate binds
active transport
the movement of molecules across a semipermeable membrane requiring an energy input
ADP
adenosine diphosphate, the unloaded form of ATP
advantageous phenotype
a biochemical, physical, or behavioural trait that increases an organism's fitness in its local environment
aerobic cellular respiration
cellular respiration that occurs in the presence of oxygen. Involves three stages, during which glucose and O2 are converted into ATP, CO2, and water
affinity
the tendency of a molecule/atom to bind or react with another molecule/atom
agarose gel
a sponge-like gel used in gel electrophoresis that contains pores for DNA fragments to move through
agglutination
the clumping of particles together. In the immune system, antibodies can help clump pathogens together
aim
the objective of an investigation or experiment
allele
an alternate form of a gene
allele frequency
the proportion of certain alleles in a gene pool
allergen
a non-pathogenic antigen that triggers an allergic reaction
allergic reaction
an overreaction of the immune system to a non-pathogenic antigen
allopatric speciation
the geographic separation of a population from a parent population resulting in the formation of a new species
allosteric site
a region on an enzyme that is not the active site
alpha helix
an organised coiled secondary structure of proteins
alternative splicing
the process where different exons may be spliced, resulting in a single gene producing multiple different mRNA strands
amino group
the functional group on amino acid molecules that is made up of one nitrogen and two hydrogens (NH2)
anaerobic fermentation
a metabolic pathway that occurs in the absence of oxygen. Involves glycolysis, followed by further reactions that convert pyruvate into lactic acid in animals, or ethanol and CO2 in yeasts
analogous structures
features present in two or more species that fulfil the same function but do not originate from a common ancestor
previous experience that may
antibiotic
medications used to kill bacteria or slow their growth
antibody
a protein produced by plasma cells during the adaptive immune response that is specific to an antigen and combats pathogens in a variety of ways. Also known as immunoglobulin
anticodon
the sequence of three nucleotides on a tRNA molecule that recognises a specific sequence of three nucleotides (codon) on an mRNA strand
antigen
any molecule that may trigger an immune response
antigen-antibody complex
a structure formed by the complementary binding between antigen and antibody molecules
antigen-presenting cell
a subgroup of phagocytes that display the antigens from consumed pathogens on their surface and interact with the adaptive immune system
antigenic drift
small and gradual mutations in the genes encoding for viral surface antigens
antigenic shift
sudden and significant mutations in the genes encoding for viral surface antigens
antimicrobial resistance
the ability of a microorganism to survive exposure to an antimicrobial agent
antiviral
medications used to treat viral infections
apoptosis
the controlled death of cells in the body. Also known as programmed cell death
arm to leg ratio
the ratio of arm length to leg length. Tree-dwelling hominids have longer arms and shorter legs, or a larger arm to leg ratio
artificial active immunity
protection against a disease created by antibodies and memory cells produced by an individual's own immune system after medical intervention. Also known as artificially acquired active immunity
artificial immunity
protection against a disease formed as a result of medical intervention. Also known as induced immunity
artificial passive immunity
protection against a disease created by antibodies from an external medical source. Also known as artificially acquired passive immunity
ATP
adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes
autoimmune disease
a disease in which an individual's immune system initiates an immune response against their own cells
B lymphocyte
a type of lymphocyte that plays an important role in humoral immunity and differentiates into plasma cells and B memory cells
B memory cell
a differentiated B lymphocyte that is responsible for providing long-lasting immunological memory of an antigen
bacterial transformation
the process by which bacteria take up foreign DNA from their environment. Scientists use this process to introduce recombinant plasmids into bacteria
bacterium (pl. bacteria)
a single-celled prokaryotic, microscopic organism that frequently grows in clusters. It can live symbiotically with other organisms and/or act as pathogens
band
a line seen in the gel after running gel electrophoresis that corresponds to a collection of DNA fragments of a specific size
beneficence
an ethical concept that seeks to maximise benefits when taking a particular position or course of action
beta-pleated sheet
an organised folded secondary structure of proteins
bias
an inclination to favour a particular position or outcome
biochemical pathway
a series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. Also known as a metabolic pathway
bioethanol
a type of biofuel that is produced via the anaerobic fermentation of plants such as sugarcane or corn
biofuel
fuel created from organic material known as biomass
biomass
organic material, including plants, animal by-products, and biological waste material. Biomass can be sourced from many industries, including farming, forestry, and food manufacturing
bipedalism
using two legs for walking upright
block mutation
a mutation that affects a large chunk of DNA, or an entire gene
blunt end
the result of a straight cut across the double-stranded DNA by an endonuclease resulting in no overhanging nucleotides
bottleneck effect
the reduction in genetic diversity that occurs when a large proportion of a population is removed due to a chance event
brow ridge
a bony ridge above the eye sockets. It is found in all primates, but is greatly reduced in Homo sapiens
bulk transport
a type of active transport that uses vesicles to move large molecules or groups of molecules into or out of the cell
bundle-sheath cell
a plant cell type that is the site of most of the Calvin cycle in C4 plants
C3 plants
plants with no evolved adaptation to minimise photorespiration
C4 plants
plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over space
CAM plants
plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over time
canine teeth
a type of tooth in mammals that is relatively long and pointed
carbon fixation
the process in living organisms where inorganic carbon, typically within carbon dioxide, is converted into organic compounds such as glucose. Carbon fixation is a central part of the light-independent stage of photosynthesis
carbon neutral
a state in which there is no net release of carbon dioxide into the atmosphere, meaning that there is a balance between the amount of CO2 that is emitted during combustion of a fuel and how much was originally absorbed during the formation process of that fuel
carboxyl group
the functional group on amino acid molecules that contains a hydroxyl group (OH) and an oxygen double-bonded to a carbon atom
cast fossil
fossil formed when a mould fossil is filled with sediment
catalyse
to increase the rate of a reaction
catalyst
a substance capable of increasing the rate of a reaction without being used up
categorical variable
a factor that is qualitative, typically describing a characteristic such as gender, birth order (1st, 2nd, 3rd), or nationality
cell-mediated immunity
an adaptive immune response in which infected or abnormal cells are destroyed by cytotoxic T cells. Also known as T cell immunity
cellular pathogen
a pathogen that has a cellular structure and exhibits the processes of a living organism. Examples include bacteria, fungi, protozoa, and parasites
cellular respiration
the process by which cells create usable energy in the form of ATP from a series of biochemical reactions, involving the breakdown of glucose
chemical barrier
a component of the first line of defence that features the use of enzymes, toxins, and acids to protect against pathogen invasion
chlorophyll
a chemical found in the thylakoids of chloroplasts. It is responsible for absorbing light energy in photosynthesis
chloroplast
a membrane-bound organelle only found in plant and photoautotroph cells that is the site of photosynthesis
chromosome
a structure made of protein and nucleic acids that carries genetic information
circulatory system
a collection of tissues and organs involved in the transportation of substances around the body. Composed of the lymphatic and cardiovascular systems
clonal expansion
the process in which many copies of a lymphocyte are generated
clonal selection
the process in which B and T cells encounter an antigen that matches their antigen-binding site, and then generate many copies of themselves
coding strand
the strand of DNA not transcribed by RNA polymerase, contains an identical sequence to the mRNA strand produced (except thymine is replaced with uracil in mRNA)
codon
the sequence of three nucleotides in mRNA coding for one amino acid
coenzyme
a non-protein organic cofactor that assists enzyme function. They release energy and are recycled during a reaction
competitive inhibitor
a molecule that hinders an enzyme by blocking the active site and preventing the substrate from binding
complement proteins
a number of different types of proteins found in the blood that opsonise, cause lysis, and attract phagocytes to invading pathogens
complementary base pairing
describes which nucleotides can form hydrogen bonds with each other. C pairs with G, A pairs with T (or U in RNA)
condensation reaction
a reaction where two monomers join to form a larger molecule, producing water as a by-product
conjugated monoclonal antibodies
monoclonal antibodies with other molecules (e.g. chemotherapy drugs or radioisotopes) attached to them
consequences-based approach
"an approach to bioethics that
control group
a group of individuals/samples that are not exposed to the independent variable. Also known as an experimental control, control treatment, or the control
controlled experiment
an investigation into the effect of an independent variable on a dependent variable, while keeping all other factors constant
controlled variable
a factor that is kept constant throughout the experiment. Also known as a constant variable
convergent evolution
the process in which distantly related species evolve similar traits over time due to the action of similar selection pressures
correlation
when there is a relationship between two variables
Note
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