VCE Biology 3/4

3' 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