100 terms

National 5 Biology Glossary

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Abiotic factor
Any condition affecting the environment that results from non-living sources
Absorption
Process by which small, soluble molecules are taken up by cells
Active site
Area on an enzyme's surface that binds with a specific substance
Active transport
Energy-demanding process in cells that moves substances against a concentration gradient
Adenine
Base that is one of three chemicals making up a nucleotide
Adenosine diphosphate
Molecule similar to ATP with one less phosphate group
Adenosine triphosphate
Molecule that is the main energy carrier molecule in cells
Aerobic respiration
Type of respiration requiring oxygen in which substrates such as glucose are completely broken down to water and carbon dioxide to release large amounts of energy
Agar
Chemical obtained from seaweed that causes a liquid to set hard
Albinism
Genetically determined condition that results in none of the normal pigment found in hair, skin and eyes
Alga
Simple one-celled or many-celled plant found mostly in water which uses sunlight to produce its own food
Algal bloom
Excess algae often associated with an increase in the nutrient level in a body of water
Allele
Different forms of a gene
Alveolus
Commonly called an air sac, blind-ending, thin-walled sad where gas exchange takes place in the lungs
Amino acids
Basic building block of protein
Amylase
Enzyme that breaks starch down into the sugar maltose
Anaemia
Reduction in the haemoglobin content of the blood that can render the person easily tired and prone to infections
Anaerobic respiration
Respiration that does not require oxygen
Anther
Male structure in a flowering plant which produces pollen
Antibiotic
Chemical produced by a microorganism used to kill or inhibit the growth of bacteria
Antibody
Large protein molecule produced in response to invasion by a foreign agent and capable of rendering it harmless
Aorta
Large artery taking blood rich in oxygen from the heart
Aphid
Sap-sucking insect that stunts the growth of the plant it infects
Artery
Vessel carrying blood to the heart
Aseptic technique
Any process that prevents contamination of the environment by the culture being used and also that prevents the environment contaminating the culture
Ateium
Upper thin-walled chamber of the heart that receives blood from the body or the lungs
Bacterium
Microscopic one-celled organism with no nucleus but with a definite cell wall and plasmids
Base
Nitrogen-containing chemical such as adenine, thymine, guanine or uracil that forms part of a nucleotide
Biodiversity
All the different species that live in an environment
Biological control
Method of controlling pests using naturally occurring living organisms to regulate the size of the pest population
Biomass
Total mass of living things in an environment expressed as the dry mass
Biome
Major area in the environment defined by its climate, flora and fauna
Biosphere
Part of the earths surface and atmosphere within which life can exist
Biotic factor
Anything that affects the environment as a result of the activities of living things
Brain
Complex of nerve cells found inside the skull where all higher level activities take place
Bronchiole
Small division of the bronchus found deep within the lungs
Bronchus
Division of the windpipe (trachea) that carries air into the lungs from the mouth
Capillary
Smallest diameter blood vessel whose walls are only one cell thick and across which exchange of gases, nutrients and wastes takes place
Carbohydrate
Chemical containing the elements carbon, hydrogen and oxygen
Carbon fixation
Combination, by photosynthetic plants, of the gas carbon dioxide with hydrogen to produce glucose
Cartilage
Collection of cells with a tough, "plastic" texture
Catalyst
Chemical that can speed up a reaction
Cell culture
Growing cells in the laboratory, outside of a living organism
Cell membrane
Outer covering of cells that regulates what can enter of leave
Cell wall
Relatively thick layer found on the outside of plant, fungal and bacterial cells. In each case, it is chemically different but functions to give the cell shape and helps percent internal cell structures
Cellulose
Main structural chemical that makes up plant cell walls
Central nervous system
Consists of brain and spinal cord
Cerebellum
Largest part of the brain occupying space from above the eyes to the back of the head
Cervix
Muscular ring at the neck of the uterus leading into the vagina
Chamber
In the heart, one of the four cavities that collect and discharge blood
Chlorophyll
Green pigment found in chloroplasts capable of trapping light energy
Chloroplast
structure found in green plant cells that contains the pigment chlorophyll and where photosynthesis takes place
chromatid
one of two identical strands forming a chromosome
chromosome complement
total number and types of chromosomes found in the nucleus of a cell
chromosome
thread like structure composed of deoxyribonucleic acid found in the nucleus and carrying genetic instructions
cillum
small threadlike structure that extends from the surface of a cell. It lines a body part such as the trachea and can move in a rhythmic and coordinated way
circulatory system
collective name for the blood vessels and the heart
collagen
important chemical found in bone and skin that gives strength
community
collection of animals and plants living together in a particular habitat
complementary base pairing
linking of bases by hydrogen in specific combinations
concentration gradient
difference in the concentration of substances from one area to another
continuous variation
continual spread across a sample of a population for variables that are often controlled by a number of factors
cuticle
continuous waxy layer that covers the surfaces exposed to the air
cytoplasm
watery substance found inside cells where all the chemical reactions of the cell take place
cytosine
base that is one of three chemicals making up a nucleotide
decomposer
any living thing that can break down dead material to allow nutrients to be recycled in ecosystems
denaturation
irreversable change in a protein, caused by changes in pH or temperature, that renders the activity of an enzyme useless
Denitrifying bacteria
Organisms that are capable of breaking down nitrate and releasing nitrogen into the atmosphere
Deoxyribonucleic acid (DNA)
Complex, helically shaped molecule of heredity within which are encoded instructions for constructing, controlling and reproducing cells by determining the synthesis of proteins
Depxyribose
5-carbon sugar found in DNA
Diabetes
Disorder that results in the inability to control blood glucose levels, commonly associated with lack of insulin
Diaphragm
Strong sheet of muscle separating the chest cavity from the lower gut cavity and is important in breathing
Diffusion
Sometimes referred to as passive transport, is the movement of substances from an area of high concentration to an area of low concentration without the use of energy
Diploid number
Total number of chromosomes in the nucleus
Discontinuous variation
Another name for discreet variation
Discrete variation
Differences in a particular feature fall into distinct categories and cannot be easily measured
Dominant allele
Form of a gene that masks the effect of the recessive form of the allele and produces a dominant phenotype
Double helix
The characteristic shape of the DNA molecule which consists of two strands, each of which turns regularly about itself to form a cylindrical shape held together by weak hydrogen bonds
Ecological barrier
Means by which a species becomes discuses into two or more sub-groups based on some change in the environment
Ecosystem
Complex community of different species of animals and plants that are dependent on each other and the environment
Effector
Structure that brings about a reaction as a result of an input from a nerve pathway
Egg
Female sex cell
Electron microscope
Microscope that does not use visible light to illuminate an object for viewing and is capable of very high magnification and great detail
Embryo
In animals developmental stage from foetal stage up to time of birth
Endocrine glands
Collection of cells that produce and release chemicals directly into the blood stream
Endocrine system
Collection of glands that release chemicals directly into the bloodstream
Enzyme
Protein that has the ability to cause a reaction in a living cell to take place quickly when it would otherwise take place slowly or not at all
Epidermis
In a multicellular organism the outer layer of cells, usually one cell thick in plants
Equator
Plane of cell along which chromosomes line up during mitosis
Ethanol
An alcohol produced during anaerobic respiration
Evolution
Process by which living things have gradually changes over a very long period of time to become better suited to survive and reproduce on there environment
Family tree
Pictorial representation of a family's inheritance patterns over a number of generations
Fat
Chemical, usually solid at room temperature, used as an energy store
Fatty acid
Chemical that, when combined with glycerol, forms fat molecules
Fauna
Collective name for the animals in a particular environment
Fermentation
Type of anaerobic respiration found in plant and yeast cells that results in the production of ethanol, carbon dioxide and small quantities of ATP
Fermenter
Device used to grow cells in large quantities very rapidly under carefully controlled conditions
Fertilisation
Fusion of male and female gametes to form a zygote
First filial generation
Offspring produced as a result of a parental cross
Flora
General term for the plant life in a particular environment