VCE Biology Units 3&4 (2023) (fixed)

i fixed it

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

activator protein

a protein coded for by a regulatory gene that increases gene expression

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

adaptive potential

the ability for a population to adjust to new environmental selection pressures

adaptive radiation

the rapid divergent evolution of a species, thereby producing a wide array of species/forms

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

afferent lymphatic vessel

thin-walled structures that collect lymph from the tissues of the body and deliver it to lymph nodes

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

airborne transmission

the spread of pathogens through air via small particles (traditionally <5 µm)

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)

amplify

to increase the quantity of a molecule by making many copies

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

anecdote

evidence involving a personal account or report of a previous experience that may provide a certain level of support for a position

personal account or report of a

previous experience that may

provide a certain level of support

for a position"

anneal

the joining of two molecules, for example two complementary DNA strands during the cooling phase of PCR

antibiotic

medications used to kill bacteria or slow their growth

antibiotic resistance gene

gene which confers antibiotic resistance

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 agent

an agent that kills or slows the growth of microorganisms. Examples include antiseptics, disinfectants, antifungals, antivirals, and antibacterial agents

antimicrobial resistance

the ability of a microorganism to survive exposure to an antimicrobial agent

antiparallel

a characteristic of DNA strands describing how each strand runs in an opposite direction to the other. One strand runs in a 3' → 5' direction and the other runs in a 5' → 3' direction

antiseptic

a substance that is applied to living tissue to kill or slow the growth of microorganisms

antivenom

a medical treatment containing antibodies specific to the toxins present in venomous bites or stings

antiviral

medications used to treat viral infections

apoptosis

the controlled death of cells in the body. Also known as programmed cell death

applied ethics

the application of ethical theories to real-life moral problems and contexts

arable land

land that is suitable for growing crops

arboreal

living in or amongst trees

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

ATP synthase

an enzyme in the inner mitochondrial membrane that uses the concentration gradient of H+ to synthesise ATP from ADP and Pi

autoantibodies

antibodies directed against an organism's own tissues

autoimmune disease

a disease in which an individual's immune system initiates an immune response against their own cells

autoreactive

a cell that recognises a self-tissue or self-antigen as non-self

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 conjugation

the process in which bacteria exchange genetic material via direct cell-cell contact

bacterial transformation

the process by which bacteria take up foreign DNA from their environment. Scientists use this process to introduce recombinant plasmids into bacteria

bacteriophage

a virus that infects prokaryotic organisms

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

base pair (bp)

a unit of measurement that corresponds to one nucleotide

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

bioethical approach

a decision-making framework that helps guide ethical behaviour

bioethical issue

an ethical dilemma pertaining to biology that typically involves a decision-making process between two or more choices or options for an action

bioethics

the study of ethical issues pertaining to biology and medicine

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

biped

an individual that moves on two legs (upright-walking)

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

bone marrow

semi-solid tissue found within bones. Serves as the primary site of the creation of red blood cells and leukocytes

booster vaccine

a vaccination given to a person later in time after they have completed their initial vaccination program to enhance their existing immunity against a disease. Also known as a booster shot

bottleneck effect

the reduction in genetic diversity that occurs when a large proportion of a population is removed due to a chance event

branch

a line on a phylogenetic tree that represents an evolutionary path

brow ridge

a bony ridge above the eye sockets. It is found in all primates, but is greatly reduced in Homo sapiens

buffer

an ion-rich solution that carries electrical current through the agarose gel

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