March 19, 2023
Active transport |
The movement of substances from a dilute solution to a more concentrated solution against a concentration gradient, requiring energy from respiration. |
Algae |
Simple aquatic organisms (protista) that make their own food by photosynthesis. |
Alveoli |
Tiny air sacs in the lungs that increase the surface area for gaseous exchange. |
Bacteria |
single-celled prokaryotic organisms |
Cell membrane |
the membrane around the contents of a cell that controls what moves in and out of the cell |
Cell wall |
the rigid structure around plant and algal cells. It is made of cellulose and strengthens the cell |
Cellulose |
the complex carbohydrate that makes up plant and algal cell walls and gives them strength |
Chlorophyll |
the green pigment contained in the chloroplasts |
Chloroplasts |
the organelles in which photosynthesis takes place |
Cytoplasm |
the water-based gel in which the organelles of all living cells are suspended and most of the chemical reactions of life take place |
Diffusion |
the spreading out of the particles of any substance in a solution, or particles in a gas, resulting in a net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient |
Eukaryotic cells |
cells from eukaryotes that have a cell membrane, cytoplasm, and genetic material enclosed in a nucleus |
Hypertonic (osmosis) |
a solution that is more concentrated than the cell contents |
Hypotonic (osmosis) |
a solution that is less concentrated than the cell contents |
Isotonic (osmosis) |
a solution that is the same concentration as the cell contents |
Mitochondria |
the site of aerobic cellular respiration in a cell |
Nucleus |
organelle found in many living cells containing the genetic information surrounded by the nuclear membrane |
Osmosis |
the diffusion of water through a partially permeable membrane from a dilute solution (which has a high concentration of water) to a concentrated solution (with a low concentration of water|) down a concentration gradient |
Partially permeable membrane |
a membrane that allows only certain substances to pass through |
Permanent vacuole |
space in the cytoplasm filled with cell sap |
Phloem |
the living transport tissue in plants that carries dissolved food (sugars) around the plant |
Plasmolysis |
the state of plant cells when so much water is lost from the cell by osmosis that the vacuole and cytoplasm shrink and the cell membrane pulls away from the cell wall |
Prokaryotic cells |
from prokaryotic organisms have a cytoplasm surrounded by a cell membrane, and a cell wall that does not contain cellulose. The genetic material is a DNA loop that is free in the cytoplasm and not enclosed by a nucleus. Sometimes there are one or more small rings of DNA called plasmids |
Resolving power |
a measure of the ability to distinguish between two separate points that are very close together |
Ribosomes |
the site of protein synthesis in a cell |
Sperm |
the male sex cells or gametes that carry the genetic material from the male parent |
Stomata |
openings in the leaves of plants, particularly on the underside and opened and closed by guard cells, allowing gases to enter and leave the leaf |
Turgor |
the pressure inside a plant cell exerted by the cell contents pressing on the cell wall |
Ventilated |
movement of air or water into and out of the gas exchange organ, for example lungs or gills |
Xylem |
the non-living transport tissue in plants that transports water from the roots to the leaves and shoots |
Adult stem cells |
stem cells that are found in adults that can differentiate and form a limited number of cells |
Cell cycle |
the three-stage process of cell division in a body cell that involves mitosis and results in the formation of two identical daughter cells |
Cloning |
the production of identical offspring by asexual reproduction |
Differentiate |
the process where cells become specialised for a particular function |
Embryonic stem cells |
stem cells from an early embryo that can differentiate to form the specialised cells of the body |
Mitosis |
part of the cell cycle where one set of new chromosomes is pulled to each end of the cell forming two identical nuclei during cell division |
Stem cells |
undifferentiated cells with the potential to form a wide variety of different cell types |
Therapeutic cloning |
a process where an embryo is produced that is genetically identical to the patient so the cells can then be used in medical treatments |
Zygote |
the single new cell formed by the fusion of gametes in sexual reproduction |
Active site |
the site on an enzyme where the reactants bind |
Amino acids |
molecules made up of carbon, hydrogen, oxygen, and nitrogen that are the building blocks of proteins |
Amylase |
enzyme that speeds up the digestion of starch into sugars |
Bile |
neutralises stomach acid to give a high pH for the enzymes from the pancreas and small intestine to work well. It is not an enzyme |
Carbohydrases |
enzymes that speed up the breakdown of carbohydrates into simple sugars |
Carbohydrates |
molecules that contain only carbon, hydrogen, and oxygen. They provide the energy for the metabolism and are found in foods such as rice, potatoes, and bread |
Catalyst |
a substance that speeds up the rate of another reaction but is not used up or changed itself |
Denatured |
the breakdown of the molecular structure of a protein so it no longer functions |
Differentiate |
the process where cells become specialised for a particular function |
Digestive system |
organ system where food is digested and absorbed |
Enzymes Fatty acids |
biological catalysts, usually proteins part of the structure of a lipid molecule |
Glycerol |
part of the structure of a lipid molecule |
Lipase |
enzymes that speed up the breakdown of lipids into fatty acids and glycerol |
Lipids |
include fats and oils and are found in foods such as butter, olive oil, and crisps. They are made of carbon, hydrogen and oxygen |
Metabolism |
the sum of all the reactions taking place in a cell or the body of an organism |
Organ |
an aggregation (collection) of different tissues working together to carry out specific functions |
Organ system |
a group of organs that work together to carry out specific functions and form organisms |
Proteases |
enzymes that speed up the breakdown of proteins into amino acids |
Proteins |
molecules that contain carbon, hydrogen, oxygen, and nitrogen and are made of long chains of amino acids. They are used for building the cells and tissues of the body and to form enzymes |
Simple sugars |
small carbohydrate units, for example glucose |
Tissue |
a group of specialised cells with a similar structure and function |
Aorta |
the artery that leaves the heart from the left ventricle and carries oxygenated blood to the body |
Arteries |
blood vessels that carry blood away from the heart. They usually carry oxygenated blood and have a pulse |
Atria |
the upper chambers of the heart |
Capillaries |
the smallest blood vessels. They run between individual cells and have a wall that is only one cell thick |
Coronary arteries |
the blood vessels that supply oxygenated blood to the heart muscle |
Double circulatory system |
the circulation of blood from the heart to the lungs is separate from the circulation of blood from the heart to the rest of the body |
Epidermal |
the name given to cells that make up the epidermis or outer layer of an organism |
Guard cells |
surround the stomata in the leaves of plants and control their opening and closing |
Haemoglobin |
the red pigment that carries oxygen around the body in the red blood cells |
Palisade mesophyll |
the upper layer of the mesophyll tissue in plant leaves made up of closely packed cells that contain many chloroplasts for photosynthesis |
Phloem |
the living transport tissue in plants that carries dissolved food (sugars) around the plant |
Plasma |
the clear yellow-liquid part of the blood that carries dissolved substances and blood cells around the body |
Platelets |
fragments of cells in the blood that play a vital role in the clotting mechanism of the blood |
Pulmonary artery |
the large blood vessel that takes deoxygenated blood from the right ventricle of the heart to the lungs |
Pulmonary vein |
the large blood vessel that carries oxygenated blood from the lungs back to the left atrium of the heart |
Red blood cells |
biconcave cells that contain the red pigment haemoglobin and carry oxygen around the body in the blood |
Spongy mesophyll |
the lower layer of mesophyll tissue in plant leaves that contains some chloroplasts and many large air spaces to give a big surface area for the exchange of gases |
Statins |
drugs used to lower blood cholesterol levels and improve the balance of high- to low-density lipoproteins in the blood |
stent |
a metal mesh placed in a blocked or partially blocked artery. They are used to open up the blood vessel by the inflation of a tiny balloon |
translocation |
the movement of sugars from the leaves to the rest of the plant through the phloem |
transpiration |
the loss of water vapour from the leaves of plants through the stomata when they are opened to allow gas exchange for photosynthesis. It involves evaporation from the surface of the cells and diffusion through the stomata |
urea |
the waste product formed by the breakdown of excess amino acids in the liver |
veins |
blood vessels that carry blood away from the heart. They usually carry deoxygenated blood and have valves to prevent the backflow of blood |
vena cava |
the large vein that brings deoxygenated blood from the body into the heart |
ventricles |
chambers of the heart that contract to force blood out of the heart |
white blood cells |
blood cells involved in the immune system of the body. They engulf pathogens and make antibodies and antitoxins |
xylem |
the non-living transport tissue in plants that transports water from the roots to the leaves and shoots |
agar gel |
widely used solid (gel) culture medium used for growing microorganisms |
aphids |
insects that penetrate the plant phloem and feed on the dissolved food. They act as plant pathogens and are also vectors that carry pathogenic viruses, bacteria, and fungi into healthy plant tissue |
binary fission |
reproduction by simple cell division, for example in bacteria |
chlorosis |
the yellowing seen on the leaves of plants when they cannot make chlorophyll due to a lack of magnesium ions |
communicable (infectious) disease |
disease caused by pathogens that can be passed from one organism to another |
culture medium |
a liquid or gel used to support the growth of microorganisms or other cultures, often containing specific nutrients |
inoculate |
introducing microorganisms to a culture medium, or introducing modified microorganisms into an individual to protect them against disease |
microorganisms |
organisms that are usually single-celled and can only be seen using a microscope . They include bacteria, fungi, viruses and protists |
mutation |
a change in the genetic material of an organism |
non-communicable diseases |
are not infectious and cannot be passed from one organism to another |
pathogens |
microorganisms that cause disease |
sexually transmitted disease (STD) |
transmitted from an infected person to an uninfected person by unprotected sexual contact |
vaccine |
dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person |
virus |
pathogens that are much smaller than bacteria and can only reproduce inside living cells of other organisms |
clinical trials |
test potential new drugs on healthy and patient volunteers |
hybridomas |
cells created during the production of monoclonal antibodies by the fusion of an antibody-specific lymphocyte and a tumour cell |
placebo |
a medicine that does not contain the active drug being tested, used in clinical trials of new medicines |
preclinical testing |
is carried out on a potential new medicine in a laboratory using cells, tissues, and live animals |
vaccine |
dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person |
benign tumours |
growths of abnormal cells that are contained in one area, usually within a membrane, and do not invade other tissues |
cancer |
the common name for a malignant tumour, formed as a result of changes in cells that lead to uncontrolled growth and division |
carcinogens |
agents that cause cancer or significantly increase the risk of developing cancer |
causal mechanism |
something that explains how one factor influences another |
correlation |
an apparent link or relationship between two factors |
ionising radiation |
has enough energy to cause ionisation in the materials it passes through, which in turn can make them biologically active and may result in mutation and cancer |
malignant tumours |
invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours. They are also known as cancers |
tumour |
a mass of abnormally growing cells that forms when the cells do not respond to the normal mechanisms that control growth and when control of the cell cycle is lost |
endothermic reaction |
a reaction that requires a transfer of energy from the environment |
glucose |
a simple sugar |
limiting factors |
limit the rate of a reaction, for example photosynthesis |
photosynthesis |
the process by which plants make food using carbon dioxide, water, and light |
aerobic respiration |
an exothermic reaction in which glucose is broken down using oxygen to produce carbon dioxide and water and release energy for the cells |
anaerobic respiration |
an exothermic reaction in which glucose is broken down in the absence of oxygen to produce lactic acid in animals and ethanol and carbon dioxide in plants and yeast. A small amount of energy is transferred for the cells |
endothermic reaction |
a reaction that requires a transfer of energy from the environment |
exothermic reaction |
a reaction that transfers energy to the environment |
glycogen |
carbohydrate store in animals |
lactic acid |
the end product of anaerobic respiration in animal cells |
oxygen debt |
the extra oxygen that must be taken into the body after exercise has stopped to complete the aerobic respiration of lactic acid |
central nervous system (CNS) |
the part of the nervous system where information is processed. It is made up of the brain and spinal cord |
cerebral cortex |
region of the brain associated with consciousness, memory, and language |
cerebellum |
region of the brain concerned with coordinating muscular activity and balance |
ciliary muscles |
muscles that contract and relax to change the shape of the lens of the eye |
coordination centres |
areas that receive and process information from receptors |
effectors |
areas (usually muscles or glands) that bring about responses in the body |
homeostasis |
the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes |
hyperopia |
long sightedness, where the rays of light from distant objects can be focused clearly on the retina but the rays of light from close objects are not focused and the objects appear blurred |
medulla |
region of the brain concerned with unconscious activities such as controlling the heart rate and breathing rate |
motor neurones |
carry impulses from the central nervous system to the effector organs |
myopia |
short sightedness, where the rays of light from close objects are brought into focus on the retina but distant objects appear blurred as the light is focused in front of the retina |
nerve |
bundle of hundreds or even thousands of neurones |
neurones |
basic cells of the nervous system that carry minute electrical impulses around the body |
receptors |
cells that detect stimuli – changes in the internal or external environment |
reflex arcs |
bring about a reflex action. They involve the sense organ, sensory neurone, relay neurone and motor neurone |
reflexes |
rapid automatic responses of the nervous system that do not involve conscious thought |
sensory neurone |
neurone that carries impulses from the sensory organs to the central nervous system |
stimuli |
changes in the external or internal environment that can be detected by receptors |
suspensory ligaments |
the ligaments that connect the lens of the eye to the ciliary muscles |
ADH |
anti-diuretic hormone helps control the water balance of the body and affects the amount of urine produced by the kidney |
adrenaline |
hormone that prepares the body for flight or fight |
auxin |
a plant hormone that controls the responses of plants to light (phototropism) and gravity (gravitropism) |
contraception |
methods of preventing pregnancy which usually involve preventing the sperm and egg from meeting |
endocrine system |
the glands that produce the hormones that control many aspects of the development and metabolism of the body, and the hormones they produce |
follicle stimulating hormone (FSH) |
causes the eggs to mature in the ovary |
gibberellins |
plant hormones that are important in initiating seed germination |
glucagon |
hormone involved in the control of blood sugar levels |
gravitropism |
the response of a plant to gravity |
hormones |
chemicals produced in one area of the body of an organism that have an effect on the functioning of another area of the body. In animals hormones are produced in glands |
insulin |
hormone involved in the control of blood sugar levels |
oestrogen |
female sex hormone that controls the development of secondary sexual characteristics in girls at puberty, and the build-up and maintenance of the uterus lining during the menstrual cycle |
ovaries |
female sex organs that produce eggs and sex hormones |
ovulation |
the release of a mature egg (ovum) from the ovary |
phototropism |
the response of a plant to light, controlled by auxin |
pituitary gland |
endocrine ‘master gland’ found in the brain that secretes a number of different hormones into the blood in response to different conditions to control other endocrine glands in the body |
testosterone |
the main male sex hormone that controls the male secondary sexual characteristics at puberty and the production of sperm |
tropism |
the responses of plant roots and shoots to environmental stimuli such as light or gravity |
type 1 diabetes |
a disorder where the pancreas fails to produce sufficient insulin |
type 2 diabetes |
a disorder where the body cells no longer respond to the insulin produced by the pancreas |
ADH |
anti-diuretic hormone helps control the water balance of the body and affects the amount of urine produced by the kidney |
dialysis |
the process of cleansing the blood through a dialysis machine when the kidneys fail |
selective reabsorption |
the process in the kidney where the materials needed in the body such as glucose, some mineral ions, and water are reabsorbed back into the blood from the filtrate |
thermoregulatory centre |
the area of the brain that is sensitive to the temperature of the blood |
vasoconstriction |
the constriction or narrowing of the blood vessels |
vasodilation |
the dilation or opening up of the blood vessels |
alleles |
different forms of the same gene sometimes referred to as variants |
asexual reproduction |
involves only one individual and the offspring is identical to the parent. There is no fusion of gametes or mixing of genetic information |
bases (DNA) |
nitrogenous compounds that make up part of the structure of DNA and RNA. They are represented by the letters A, T, C, and G |
carriers |
individuals who are heterozygous for a recessive allele linked to a genetic disorder. Carriers have one healthy allele so are not affected themselves but they can pass on the affected allele to their offspring |
cystic fibrosis |
an inherited disorder that affects the lungs, digestive, and reproductive system and is inherited through a recessive allele |
dominant allele |
the phenotype will be apparent in the offspring even if only one of the alleles is inherited |
genetic engineering |
the process by which scientists can manipulate and change the genotype of an organism |
genotype |
the genetic makeup of an individual for a particular characteristic, for example hair or eye colour |
heterozygote |
individual with different alleles for a characteristic |
homozygote |
individual with two identical alleles for a characteristic |
meiosis |
two stage process of cell division that reduces the chromosome number of daughter cells. It is involved in making gametes for sexual reproduction |
mutation |
a change in the genetic material of an organism |
natural selection |
the process by which evolution takes place. Organisms produce more offspring than the environment can support. Only those that are most suited to their environment will survive to breed and pass on their useful characteristics to their offspring |
nucleotide |
a molecule made up of a sugar, a phosphate group, and one of four different bases. They are key units in the structure of DNA and RNA |
phenotype |
the physical appearance / biochemistry of an individual for a particular characteristic |
polydactyly |
a dominant inherited disorder that results in babies born with extra fingers and/or toes |
Punnett square diagram |
a way of modelling a genetic cross and predicting the outcome using probability |
recessive |
a phenotype that will only show up in the offspring if both of the alleles coding for that characteristic are inherited |
sex chromosomes |
carry the information that determines the sex of an individual |
sexual reproduction |
involves the joining (fusion) of male and female gametes producing genetic variation in the offspring |
mutation |
a change in the genetic material of an organism |
natural selection |
the process by which evolution takes place. Organisms produce more offspring than the environment can support. Only those that are most suited to their environment will survive to breed and pass on their useful characteristics to their offspring |
selective breeding |
speeds up natural selection by selecting animals or plants for breeding that have a required characteristic |
tissue culture |
a modern way of cloning plants that allows thousands of new plants to be created from one piece of plant tissue |
archaea |
one of the three domains, containing primitive forms of bacteria that can live in many of the extreme environments of the world |
classification |
the organisation of living organisms into groups according to their similarities |
domain |
the highest level of classification. There are three domains – Archaea, Bacteria and Eukaryota |
evolutionary trees |
models used to explain the evolutionary links between groups of organisms |
extinction |
the permanent loss of all members of a species from an area or from the world |
speciation |
the process by which two species evolve from a single original species by natural selection |
species |
the smallest group of clearly identified organisms in Linnaeus’s classification system, often described as a group of organisms that can breed together and produce fertile offspring |
abundance |
a measure of how common or rare a particular type of organism is in a given environment |
adaptations |
special features that make an organism particularly well suited to the environment where it lives |
community |
group of interdependent living organisms in an ecosystem |
competition |
the process by which living organisms compete with each other for limited resources such as food, light, or reproductive partners |
distribution |
where particular types of organisms are found within an environment |
extremophile |
an organism that can survive and reproduce in extreme conditions |
interdependence |
the network of relationships between different organisms within a community, for example each species depends on other species for food, shelter, pollination, seed dispersal, etc. |
mean |
the arithmetical average of a series of numbers |
median |
the middle value in a list of numbers |
mode |
the number which occurs most often in a set of data |
quadrat |
a sample area used for measuring the abundance and distribution of organisms in the field |
quantitative sampling |
records the numbers of organisms rather than just the type |
range |
the maximum and minimum values for the independent or dependent variables – important in ensuring that any patterns are detected |
sample size |
the size of a sample in an investigation |
transect |
a measured line or area along which ecological measurements are made |
biomass |
the amount of biological material in an organism |
carbon cycle |
the cycling of carbon through the living and non-living world |
decomposers |
microorganisms that break down waste products and dead bodies
|
primary consumer |
animals that eat producers |
producers |
organisms such as plants and algae that can make food from raw materials such as carbon dioxide and water |
secondary consumer |
animals that eat the primary consumers |
acid rain |
rain that has an acidic pH caused by acid gases that have been released into the atmosphere, such as sulfur dioxide and nitrogen oxide. These gases dissolve in rainwater and react with oxygen in the air to for acid |
biodiversity |
a measure of the variety of all the different species of organisms on Earth |
deforestation |
the removal of trees from a large area of land so that the area can be used for other purposes, such as farming or building |
incident energy |
light from the Sun arriving at the surface of the Earth |
trophic level |
feeding levels in an ecosystem |