Keywords Flashcards
Topic : Causes of disease
Pathogen
A micro-organism that causes disease
Topic : Enzymes and Digestive system
Digestion
Physical and chemical breakdown of food
Topic : Enzymes and Digestive system
Hydrolysis
Splitting up of molecules by adding water to them.
Enzymes do this to help break down molecules.
Topic : Enzymes and Digestive system
Monomer
One of many small molecules that combine to form a
larger one
Topic : Enzymes and Digestive system
Polymer
Larger molecule made up of repeating smaller
molecules
Topic : Enzymes and Digestive system
Condensation Reaction
When 2 monosaccharides combine, water is removed
Topic : Enzymes and Digestive system
Glycosidic Bond
The bond in a disaccharide
Topic : Enzymes and Digestive system
Peptide Bond
The bond between 2 amino acids in a protein, formed
by a condensation reaction
Topic : Enzymes and Digestive system
Polypeptide
A long chain of amino acids
Topic : Enzymes and Digestive system
Hydrogen Bonds
Weak bonds between oxygen and hydrogen holding the
secondary structure of a protein in a coil
Topic : Enzymes and Digestive system
Activation Energy
The minimum amount of energy needed to bring about
a reaction
Topic : Enzymes and Digestive system
Active site
The region on an enzyme where the substrate fits
Topic : Enzymes and Digestive system
Substrate
The molecule on which the enzyme acts
Topic : Enzymes and Digestive system
Enzyme-Substrate Complex
Formed when an enzyme and a substrate fit together
and form temporary bonds
Topic : Enzymes and Digestive system
Denaturation
Permanent changes in the structure of a protein;
enzyme’s active site changes shape so the substrate no
longer fits
Topic : Enzymes and Digestive system
Competitive Inhibitor
Molecule that binds to the active site of an enzyme
Topic : Enzymes and Digestive system
Non-competitive inhibitor
Bind to the enzyme at a position other than the active
site
Topic : Cells and movement in and out of them
Resolution
The minimum distance apart 2 objects are, so that they
look like separate objects under the microscope
Topic : Cells and movement in and out of them
Cell Fractionation
The process by which cells are broken up and the
organelles separated out
Topic : Cells and movement in and out of them
Prokaryotic Cells
Cells that lack a nucleus and any membrane-bound
organelles
Topic : Cells and movement in and out of them
Eukaryotic Cells
Cells that have a nucleus, chromosomes and other
membrane-bound organelles
Topic : Cells and movement in and out of them
Saturated Lipids
Fatty acids with only C-C single bonds
Topic : Cells and movement in and out of them
Unsaturated Lipids
Fatty acids with one or more C=C double bonds
Topic : Cells and movement in and out of them
Hydrophilic
Attracted to water
Topic : Cells and movement in and out of them
Hydrophobic
Attracted to fat
Topic : Cells and movement in and out of them
Extrinsic Proteins
Proteins on the surface of the bilayer
Topic : Cells and movement in and out of them
Intrinsic Proteins
Proteins spanning the bilayer
Topic : Cells and movement in and out of them
Diffusion
The net movement of molecules or ions from a region
of high concentration to a region of low concentration
Topic : Cells and movement in and out of them
Osmosis
The passage of water from a region of high water
potential to a region of low water potential, across a
partially permeable membrane
Topic : Cells and movement in and out of them
Active Transport
The movement of molecules or ions into or out of a cell
from a region of lower concentration to a region of
higher concentration using energy and carrier
molecules
Topic : Lungs and Lung Disease
Pulmonary
Ventilation
Tidal Volume x Ventilation Rate
Topic : Lungs and Lung Disease
Short Diffusion Pathway
Thin alveoli walls allow materials to cross quickly as the
path is short
Topic : Lungs and Lung Disease
Diffusion Gradient
Movement of air and blood help to maintain diffusion
gradients – keep Oxygen moving in and CO2 out
Topic : Lungs and Lung Disease
Pulmonary Fibrosis
Thickening of lung epithelia due to scarring
Topic : Lungs and Lung Disease
Asthma
An allergic reaction where histamine is released and the
airway linings become inflamed
Topic : Lungs and Lung Disease
Emphysema
Destruction of the elastic tissue in the lungs due to
smoking
Topic : The Heart and Heart Disease
Atrial Systole
Contraction of the atria
Topic : The Heart and Heart Disease
Ventricular Systole
Contraction of the ventricles
Topic : The Heart and Heart Disease
Diastole
Relaxation of the heart
Topic : The Heart and Heart Disease
Cardiac Output
The volume of blood pumped by one ventricle of the
heart in one minute
Topic : The Heart and Heart Disease
Myogenic
Contraction of the heart is initiated from within the
muscle itself
Topic : The Heart and Heart Disease
Sino-atrial node
SAN, sends out the initial wave of electrical activity to
make the atria contract
Topic : The Heart and Heart Disease
Atrio-ventricular node
AVN, sends a wave of electrical activity down the
bundle of His, making the ventricles contract from the
base upwards
Topic : The Heart and Heart Disease
Atheroma
A fatty deposit in the wall of an artery
Topic : The Heart and Heart Disease
Aneurysm
Weakened artery walls swell and may burst
Topic : The Heart and Heart Disease
Thrombosis
When an atheroma breaks and a blood clot forms
Topic : The Heart and Heart Disease
Myocardial Infarction
A heart attack
Topic : The Heart and Heart Disease
Low-density lipoproteins
Transport cholesterol to tissues that may get deposited
Topic : The Heart and Heart Disease
High-density lipoproteins
Remove cholesterol from tissues
Topic : Immunity
Non-Specific Defences
Mechanisms that don’t distinguish between one type of
pathogen or another e.g. skin
Topic : Immunity
Specific Defences
Mechanisms that do distinguish between different
pathogens e.g. lymphocytes
Topic : Immunity
Phagocytosis
Pathogens are engulfed into vesicles (called
phagosomes) and broken down by enzymes
Topic : Immunity
Antigens
Part of an organism that is recognised as non-self and
triggers an immune response (usually they are proteins)
Topic : Immunity
Cell-mediated Immunity
T lymphocytes recognise antigen-presenting cells that
have been invaded and undergo mitosis to respond
Topic : Immunity
Humoral Immunity
Immunity involving B cells and antibodies
Topic : Immunity
Antigenic Variability
Viruses such as flu have many different strains with
different antigens on them
Topic : Immunity
Antibodies
Proteins synthesised by B cells, consisting of heavy and
light chains and variable and constant regions
Topic : Immunity
Antigen-Antibody Complex
Formed when antigens bind to a specific site on the
antibody
Topic : Immunity
Complementary Shape
Antigens have a shape that means they fit into their
specific antibody
Topic : Immunity
Monoclonal Antibodies
Isolation and cloning of a single type of antibody
Topic : Immunity
Passive Immunity
The introduction of antibodies from an outside source
Topic : Immunity
Active Immunity
Stimulation of antibody production by the individual’s
own immune system
Topic : Immunity
Vaccination
The introduction of a substance into the body with the
purpose of stimulating active immunity against a
particular disease
Topic : Immunity
Herd Immunity
Vaccinating most of a population so that no-one has the
disease and transmission is stopped
Topic : Variation
Interspecific Variation
Differences between different species
Topic : Variation
Intraspecfic Variation
Differences between members of the same species
Topic : DNA and Meiosis
Nucleotide
Section of DNA made up of sugar, phosphate and a base
Topic : DNA and Meiosis
Complementary
A always bonds to T and C always bonds to G (they are
complementary to each other)
Topic : DNA and Meiosis
Gene
A section of DNA that codes for making a polypeptide
Topic : DNA and Meiosis
Triplet Code
3 bases code for an amino acid
Topic : DNA and Meiosis
Chromosome
Thread-like structure made of protein and DNA, passes
hereditary information on
Topic : DNA and Meiosis
Homologous Chromosomes
2 chromosomes determining the same characteristics
one from mother, one from father
Topic : DNA and Meiosis
Allele
One of the different forms of a gene
Topic : DNA and Meiosis
Meiosis
Cell division that produces 4 haploid (half the
chromosomes), genetically different, daughter cells
Topic : DNA and Meiosis
Locus
Position of a gene on a chromosome
Topic : DNA and Meiosis
Independent Segregation
Homologous pairs randomly separate during meiosis 1,
into separate cells
Topic : DNA and Meiosis
Crossing Over
The process where chromatids break and rejoin with
their homologous chromosome to exchange alleles
Topic : Genetic Diversity
Selective Breeding
Breeding individuals with desired characteristics
together and selecting the offspring that show the
desired characteristics
Topic : Genetic Diversity
Founder Effect
A few individuals colonise a new region, carrying a small
amount of the alleles of the larger population
Topic : Genetic Diversity
Genetic Bottleneck
A drop in allele variety due to a large decrease in
population size
Topic : The Variety of Life
Affinity for Oxygen
Haemoglobin (Hb) with a high affinity takes up oxygen
easily and releases in less readily. Hb with a low affinity
takes up oxygen less easily, but releases it more readily.
Topic : The Variety of Life
Associating
The process by which Hb combines with oxygen (in the
lungs)
Topic : The Variety of Life
Dissociating
The process by which Hb releases oxygen (in the
tissues)
Topic : The Variety of Life
Oxygen Dissociation Curve
The s-shaped curve shown by how Hb binds oxygen
first molecule is hard to load, next 3 load easily
Topic : The Variety of Life
Starch
Storage molecule in plants, it is coiled, insoluble and can
by hydrolysed to form α-glucose
Topic : The Variety of Life
Glycogen
Storage molecule in animals, which has short chains so
it can be readily hydrolysed to α-glucose
Topic : The Variety of Life
Cellulose
Parallel chains of β-glucose joined by hydrogen bonds,
forms microfibrils for strength
Topic : The Variety of Life
Chloroplasts
Organelle in plant cells containing grana, thylakoids and
stroma. Photosynthesis occurs here.
Topic : The Cell Cycle
Semi-conservative Replication
The way DNA makes exact copies of itself by unwinding
the double helix. Each chain acts as a template for the
new strands.
Topic : The Cell Cycle
Mitosis
Cell division where 2 daughter cells are produced that
have the same number of chromosomes as the parent
Topic : The Cell Cycle
Haploid
Cells have half the number of chromosomes
Topic : The Cell Cycle
Diploid
Cells have a full set of chromosomes
Topic : The Cell Cycle
Prophase
Chromosomes become visible, nuclear envelope
disappears
Topic : The Cell Cycle
Metaphase
Chromosomes align along equator of cell
Topic : The Cell Cycle
Anaphase
Chromatids move to opposite poles
Topic : The Cell Cycle
Telophase
Nuclear envelope reforms
Topic : The Cell Cycle
Cell Cycle
A cell’s regular cycle of division, followed by periods of
growth
Topic : Cellular Organisation
Cell Differentiation
Cells become specialised in their structure to suit their
roles
Topic : Cellular Organisation
Tissue
A collection of similar cells that perform a specific
function
Topic : Cellular Organisation
Organ
A combination of tissues, co-ordinated to perform a
variety of functions
Topic : Cellular Organisation
Organ Systems
Organs working together as a single unit
Topic : Exchange and transport
Surface area to volume ratio
For exchange to be efficient, an organism needs a large
surface area to volume ratio (bigger animals have a
smaller ratio)
Topic : Exchange and transport
Spiracles
Pores on the body surface of insects that open and
close to allow gases to diffuse in and out
Topic : Exchange and transport
Gill Lamellae
Parts of fish gills that increase the surface area and
where the blood flows through for gas exchange
Topic : Exchange and transport
Countercurrent Exchange
Blood and water flow in opposite directions to maintain
a diffusion gradient
Topic : Exchange and transport
Stomata
Pores in the underside of a leaf that can be opened and
closed by guard cells
Topic : Exchange and transport
Double Circulatory System
Blood passes through the heart twice on a full circuit of
the body
Topic : Exchange and transport
Arteries
Blood vessels that carry blood away from the heart
small lumens, thick muscle and elastic layers
Topic : Exchange and transport
Veins
Blood vessels that carry blood back to the heart (large
lumens, thin muscle and elastic layers, have valves)
Topic : Exchange and transport
Tissue Fluid
Fluid that surrounds the cells of the body, it supplies
nutrients to the cells and removes waste products
Topic : Exchange and transport
Ultrafiltration
Filtration assisted by blood pressure
Topic : Exchange and transport
Apoplastic Pathway
Route through the cell walls by which water and
minerals are transported into the plant
Topic : Exchange and transport
Symplastic Pathway
Route through the cytoplasm and plasmodesmata of
plant cells by which water and minerals are transported
Topic : Exchange and transport
Cohesion
Water molecules stick together by hydrogen bonds
Topic : Exchange and transport
Cohesion-Tension
Transpiration pull on the water puts the xylem under
pressure
Topic : Exchange and transport
Transpiration
Evaporation of water from a plant
Topic : Exchange and transport
Xerophytes
Plants adapted to living in dry conditions
Topic : Classification
Species
A group of similar organisms that can breed together to
produce fertile offspring
Topic : Classification
Classification
Grouping of organisms
Topic : Classification
Taxonomy
Theory and practice of biological classification
Topic : Classification
Phylogeny
The evolutionary relationships between organisms
Topic : Evidence for Relationships Between Organisms
DNA Hybridisation
A technique used to determine the similarities between
the DNA of different organisms
Topic : Evidence for Relationships Between Organisms
Hybridisation
Double strands form with one strand from each species,
closely related organisms will share complementary
bases
Topic : Evidence for Relationships Between Organisms
Courtship Behaviour
Signals and displays between males and females of the
same species to enable successful mating to occur
Topic : Adaptation and Selection
Adaptation
Organisms adjust to suit the changing environment
where they live
Topic : Adaptation and Selection
Mutations
A change in the base sequence of DNA
Topic : Adaptation and Selection
Conjugation
One bacterial cell transfers DNA to another bacterial
cell
Topic : Adaptation and Selection
Antibiotics
Substances that can destroy or inhibit the growth of
micro-organisms
Topic : Adaptation and Selection
Antibiotic Resistance
Antibiotics have a reduced effectiveness at killing
bacteria due to chance mutations
Topic : Adaptation and Selection
Plasmids
Circular loops of DNA in bacteria
Topic : Biodiversity
Biodiversity
The variety in the living world (including number of
different species, variety of genes and the range of
habitats)
Topic : Populations
Ecosystem
Self-contained unit made up of the biotic and abiotic
factors in an area
Topic : Populations
Population
A group of individuals of the same species in a habitat
Topic : Populations
Community
The organisms of all species that live in the same area
Topic : Populations
Abiotic Factors
Concerned with the non-living part of the environment
Topic : Populations
Biotic Factors
Concerned with the living organisms in the environment
Topic : Populations
Interspecific Competition
Competition between organisms of different species
Topic : Populations
Intraspecific Competition
Competition between organisms of the same species
Topic : ATP
Phosphorylation
The process of adding a phosphate group (e.g. ADP –>
ATP)
Topic : Photosynthesis
Light Dependent Reaction
Stage of photosynthesis in which light energy is
required to produce ATP and reduced NADP
Topic : Photosynthesis
Light Independent Reaction
Stage of photosynthesis which does not require light energy directly, but does need the products of the light
dependent reaction to reduce CO2 and form
carbohydrate
Topic : Photosynthesis
Oxidation
Loss of electrons, combining oxygen with a substance
Topic : Photosynthesis
Reduction
Gain of electrons, loss of oxygen from a substance
Topic : Photosynthesis
Electron Carrier Molecules
A chain of carrier molecules along which electrons pass,
releasing energy in the form of ATP as they do so
Topic : Photosynthesis
Photolysis of Water
Light energy splits water molecules, yielding electrons,
hydrogen ions and oxygen (light-dependent reaction)
Topic : Photosynthesis
Calvin Cycle
A biochemical pathway (part of the light-independent
reaction) where CO2 is reduced to form carbohydrate
CO2 + RuBP –> GP –> TP –> Glucose or RuBP
Topic : Respiration
Glycolysis
First part of cellular respiration in which glucose is
broken down (in the cytoplasm) to 2 molecules of
pyruvate
Topic : Respiration
Link Reaction
Process linking Glycolysis to the Krebs Cycle (in the
matrix of the mitochondria), where the 2 molecules of
pyruvate are converted to CO2 and acetylcoenzyme A
Topic : Respiration
Krebs Cycle
Introducing acetylcoenzyme A into a cycle of oxidationreduction
reactions (in the matrix of the mitochondria)
that yield some ATP and a large number of electrons
Topic : Respiration
Electron Transport Chain
Use of electrons from the Krebs Cycle to synthesise ATP
via a series of oxidation-reduction reactions
Topic : Respiration
Anaerobic Respiration
Releasing energy from glucose without oxygen
(produces lactate in animals and ethanol in plants and
some micro-organisms)
Topic : Energy and Ecosystems
Trophic Level
Each stage in a food chain
Topic : Energy and Ecosystems
Consumers
An organism that obtains its energy by feeding on other
organisms
Topic : Energy and Ecosystems
Gross Production
Total quantity of energy that the plants in a community
convert to organic matter
Topic : Energy and Ecosystems
Net Production
Gross production – respiratory losses
Topic : Energy and Ecosystems
Energy Transfer
(Energy available after the transfer / energy available
before the transfer) x 100
Topic : Energy and Ecosystems
Pyramid of Number
A pyramid drawn with bar lengths proportional to the
numbers of organisms present
Topic : Energy and Ecosystems
Pyramid of Biomass
A pyramid drawn with bar lengths proportional to the
mass of plants/animals
Topic : Energy and Ecosystems
Pyramid of Energy
A pyramid drawn with bar lengths proportional to the
energy stored in organisms
Topic : Energy and Ecosystems
Selective Breeding
Breeding of organisms by human selection of parents
for certain characteristics
Topic : Nutrient Cycles
Saprobiotic Micro-organism
(Saprophyte) An organisms that gets it food from the
dead or decaying remains of other organisms
Topic : Nutrient Cycles
Greenhouse Gases
Gases such as methane and CO2 which trap more heat
energy, raising the Earths temperature
Topic : Nutrient Cycles
Ammonification
Production of ammonia from e.g. urea and proteins
Topic : Nutrient Cycles
Nitrification
Converting ammonia into nitrites and then nitrates
Topic : Nutrient Cycles
Nitrogen Fixation
Conversion of nitrogen gas into nitrogen-containing
compounds
Topic : Nutrient Cycles
Denitrification
Conversion of soil nitrates into mitrogen gas
Topic : Nutrient Cycles
Leaching
Process by which nutrients are washed from the soil
into watercourses
Topic : Nutrient Cycles
Eutrophication
Consequence of an increase in nutrients in
watercourses that leads to a decrease in biodiversity
Topic : Inheritance and Selection
Genotype
The genetic composition of an organism
Topic : Inheritance and Selection
Phenotype
The characteristics of an organism (often visible),
resulting from its genotype and the environment
Topic : Inheritance and Selection
Gene
A length of DNA that codes for a polypeptide
Topic : Inheritance and Selection
Allele
One form of a gene
Topic : Inheritance and Selection
Homologous Chromosomes
A pair of chromosomes that have the same gene loci
and determine the same features
Topic : Inheritance and Selection
Dominant
An allele that is always expressed in the phenotype
Topic : Inheritance and Selection
Recessive
An allele that is only expressed in the phenotype when
there is another identical allele
Topic : Inheritance and Selection
Heterozygous
When the alleles are different for a particular gene
Topic : Inheritance and Selection
Homozygous
When the alleles are the same for a particular gene
Topic : Inheritance and Selection
Sex Linkage
Any gene that is carried on the X or Y chromosome
Topic : Inheritance and Selection
Co-dominance
Both alleles are equally dominant and are both
expressed in a phenotype
Topic : Inheritance and Selection
Multiple Alleles
More than 2 possible alleles for a particular gene
Topic : Inheritance and Selection
Gene Pool
All the alleles of all the genes of all the individuals in a
population at any one time
Topic : Inheritance and Selection
Allelic Frequency
The number of times the allele occurs within a gene
pool
Topic : Inheritance and Selection
Stabilising Selection
Selection that favours average individuals
Topic : Inheritance and Selection
Directional Selection
Selection that favours individuals at one extreme
Topic : Inheritance and Selection
Speciation
The evolution of new species from existing species
Topic : Inheritance and Selection
Geographical Isolation
When a physical barrier prevents two populations from
breeding with one another
