Biology Key Words

Define accuracy

How close a measured or calculated value is to the true value.

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Define precision

The closeness of agreement between measured values obtained by repeated measures.

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Define electron micrograph

Photograph of an image seen using an electron microscope.

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Define organelles

Small structures within cells, each of which has a specific function.

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Define photomicrograph

Photograph of an image seen using an optical microscope.

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Magnification Equation

Image size= Actual size x Magnification

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Nucleus (function)

--Control centre of cell --Stores genetic material --provides instructions for protein synthesis

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Rough Endoplasmic Reticulum (function)

--Transport system- cisternae form channels for transport --Large surface area for ribosomes-protein synthesis

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Smooth Endoplasmic Reticulum (function)

--contains enzymes that catalyse reactions in lipid metabolism-synthesis of cholesterol,lipids/phospholipids & steroid hormones --absorption, synthesis and transport of lipids

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Golgi Apparatus (function)

--Proteins are modified-adding sugar to become glycoproteins -adding lipids to make lipoproteins -folded into 3D shape --proteins packaged into vesicles

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Mitochondria (function)

--Site of ATP production during respiration --Self-replicating --Abundant in cells with more metabolic activity taking place

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Chloroplasts (function)

--Site of photosynthesis -- 1st light trapped in grana, water split for H+ ions --2nd when Hydrogen reduces carbon dioxide, using energy from ATP, to make carbohydrates, occurs in stroma.

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Vacuole (function)

--Only in plants --filled with water and solutes --can support plant when turgid

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Lysosomes (function)

--compartmentalise powerful hydrolytic enzymes --engulf old organelles and foreign material and return digested material to be used by organelle.

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Cilia (function)

--epithelial cells lining airways have cilia --Nearly all cells have one cilium (acts as antenna with receptors)

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Undulipodia

The tail on a spermatozoon (sperm) cell- enables it to move

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Ribosomes (function)

NO MEMBRANE- bound to exterior RER- synthesise proteins -when free in cytoplasm- site of protein assembly

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Centrioles (function)

Formed from spindle. Move chromosomes during cell division. --Involved in formation of cilia and undulipodia -centrioles line up beneath plasma membrane and then microtubules sprout from centrioles to form the cilia.

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Cytoskeleton (function)

--microfilaments give support and mechanical strength --microtubules help organelles to move through the cytoplasm -form spindle and make up cilia and centrioles. --Intermediate filaments-made of proteins -anchor nucleus in cytoplasm

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Motor proteins

Dynein and Kinesin

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Cellulose Cell Wall

Plant cells

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Chitin Cell Wall

Fungi

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Define Carbohydrates

molecules of C, H and O. Mono/poly/disaccharides

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Define Glycosidic bond

A bond formed between two monosaccharides by a condensation reaction.

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Define Lipids

Group of substances that are soluble in alcohol rather than water. Triglycerides, phospholipids, glycolipids and cholesterol.

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Define phospholipid

Molecule consisting of glycerol, two fatty acids and one phosphate group.

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Define peptide bond

A bond formed when two amino acids are joined by a condensation reaction

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Define primary structure

The sequence of amino acids.

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Define secondary structure

the coiling of the amino acid chain (due to hydrogen bonding). Causes alpha helix and beta pleated sheet.

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Define tertiary structure

3D shape of a protein molecule (due to H-bonds, disulfide bridges, ionic bonds and hydrophobic interactions).

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Define quaternary structure

Protein structure where a protein consists of more than one polypeptide chain.

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Define fibrous protein

A relatively long, thin structure, is insoluble in water and metabolically inactive often having a structural role within an organism.

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Define globular protein

Has molecules of a relatively spherical shape, which are soluble in water, and often have metabolic roles within the organism.

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Define prosthetic group

A non-protein component that forms a permanent part of a functioning protein molecule.

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Define transcription

The process of making messenger RNA from a DNA template

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Define translation

Formation of a protein, at ribosomes, by assembling AA into a sequence according to the instructions carried from DNA by mRNA.

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Peptidoglycan cell wall

Prokaryotic cells (divide by binary fission

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Maltose

a-glucose + a-glucose

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Sucrose

a-glucose + fructose

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Lactose

a-glucose + B-galactose

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Cellobiose

B-glucose + B-glucose

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Define disaccharides

Any class of sugars whose molecules contain two monosaccharide residues joined by a condensation reaction.

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Define polysaccharides

Polymers of monosaccharides that are made of hundreds or thousands of monosaccharide monomers bonded together.

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Define glycogen

The energy store in humans. Large polysaccharide molecule, chain between carbon 1-4. branches carbon 1-6 (glycosidic bonds)

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Define amylopectin

Constituent of starch. Large polysaccharide molecule, chain between carbon 1-4. branches carbon 1-6 (glycosidic bonds)

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Define amylose

A molecule of polysaccharide with long straight chains between 100-1000 a-glucose. Constituent of starch. Glycosidic bonds carbon 1-4

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Define glycerol

Has 3 carbon atoms. An alcohol with 3 -OH groups.

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Define fatty acids

Has a carboxyl group (-COOH) attached to a hydrocarbon tail. Can be anything from 2-20 carbons long.

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Define conjugated protein

A protein associated with a non-protein component.

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Define colourimeter

An instrument for measuring the absorbance of different wavelengths of light in a solution

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Define double helix

Shape of DNA molecule due to the coiling of the two sugar-phosphate backbone strands.

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Define nucleotide

Molecule consisting of a five-carbon sugar, a phosphate group and a nitrogenous base.

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Define DNA polymerase

Enzyme that catalyses the formation of DNA from activated deoxyribose nucleotides, using single stranded DNA as a template.

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Define helicase

Enzyme that catalyses the breaking down of hydrogen bonds between the nitrogenous pairs of bases in DNA

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Define semi-conservative replication

How DNA replicates, resulting in two new molecules- each containing one old strand and one new. One old strand is conserved in each new molecule.

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Define gene

length of DNA that codes for a polypeptide or a length of RNA that is involved in regulating gene expression.

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Define active site

Indented area on the surface of an enzyme molecule with a shape that is complementary to the shape of the substrate molecule.

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Define catalyst

Chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction.

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Define substrate

Molecule that is altered by an enzyme-catalysed reaction.

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Define cofactor

A substance that has to be present to ensure that an enzyme-catalysed reaction takes place at the appropriate rate.

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Define enzyme-substrate complex

Complex formed by temporary binding of enzyme and substrate molecules during an enzyme catalysed reaction.

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Define Q10

Temperature coefficient calculated by dividing the rate of reaction at (T + 10)*C by the rate of reaction at T*C

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Define buffer

Something that resists changes in pH

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Define limiting factor

An environmental factor that limits the rate of a biological process. When a process is controlled by a number of factors, the factor that is in least supply will limit the process. Increase of the factor will increase the process speed.

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Define competitive inhibition

The inhibitor molecule has a similar shape to that of the substrate molecule and competes for the active site. It blocks the active site and prevents the formation of the enzyme-substrate complex.

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Define non-competitive inhibition

The inhibitor molecule attaches to part of the molecule but not the active site. It changes the shape of the active site and prevents the formation of the enzyme-substrate complex.

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Define toxin

A substance that is poisonous to living cells/organisms. They exert their effect because they inhibit enzymes.

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Define glycolipid

Lipid/phospholipid with a chain of carbohydrate molecules attached.

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Define glycoprotein

Protein with a chain of carbohydrate molecules attached.

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Define glycocalyx

All the carbohydrate molecules on the exterior of a plasma membrane.

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Define facilitated diffusion

Movement of molecules from an area of high concentration to an area of low concentration across a partially permeable membrane via protein channels or carriers- PASSIVE

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What happens when an animal cell is put in pure water?

Water moves in by osmosis and the cell is cytolysed (it bursts open) -IRREVERSIBLE

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What happens when an animal cell is put in sugar solution?

Water moves out by osmosis and the cell is crenated (it appears wrinkled and shrinks)- REVERSIBLE

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What happens when a plant cell is put in pure water?

Water moves in by osmosis and the cell becomes turgid (cell membrane pushes against the cell wall -REVERSIBLE

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What happens when a plant cell is put in sugar solution?

Water moves out by osmosis and the cell is plasmolysed (it shrinks so the cell membrane pulls away from the cell wall)- IRREVERSIBLE

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Define carrier proteins

Membrane proteins that have specific regions, or sites, that combine reversibly with certain solute molecules or ions. They also have a region that binds to and allows the hydrolysis of ATP to release enzymes.

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Define cytokinesis

Cytoplasmic division following nuclear division, resulting in two new daughter cells.

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Define interphase

Phase of cell cycle where the cell is not dividing; it is subdivided into growth and synthesis phases.

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Define prophase

DNA super-coils, the nuclear envelope breaks down, the centriole divides into two, a spindle forms from the daughter centrioles.

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Define metaphase

The pairs of chromatids line up at the equator and attach to the spindle threads by their cedntromeres.

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Define anaphase

The centromere of the pairs of chromatids split, motor proteins pull each sister chromatid along the spindle fibres. The chromosomes now move in a v shape to the poles

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Define telophase

The separated chromosomes reach the poles. A new nuclear envelope forms around each set of chromosomes.

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Define allele

A version of a gene/gene variant

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Define haploid

Having only one set of chromosomes- represented by n

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Define meristem

Area of unspecialised cells within a plant that can divide and differentiate into other cell types

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Define regenerative medicine

Stem cells may be used to populate a bioscaffold of an organ and then directed to develop and grow into a specific organ for transplanting.

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Define pluripotent

Cell which can differentiate into any type of cell except placental cells.

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Define metabolic activity

Any cellular reaction

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Define metabolic rate

Rate of cellular reactions

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Define alveoli

Tiny folds of the lung epithelium that increase the surface area

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Define bronchi and brochioles

Smaller airways leading into the lungs

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Define intercostal muscles

Muscles between the ribs. Contraction of the external intercostal muscles raises the ribcage.

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3 factors for an efficient exchange system

-- Large surface area --Short diffusion distance --A good blood supply

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Define residual volume

The volume of air that remains in the lungs even after forced expiration.

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Define buccal cavity

The mouth of a fish

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Define primary lamellae

Slender branches of tissue that make up the gill. They are often called filaments.

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Define secondary lamellae

Folds of the primary lamellae to increase surface area. They are also called gill plates.

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Define operculum

A bony flap that covers and protects the gills.

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Define spiracle

An external opening or pore that allows air in or out of the tracheae.

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Define tracheal fluid

The fluid found at the ends of the tracheoles in the tracheal system.

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Define tracheal system

A system of air filled tubes in insects.

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Define ostia

Pores in the heart of an insect that allow blood from the body to enter the heart.

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Define hydrostatic pressure

The pressure that a fluid exerts when pushing against the sides of a vessel or container.

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Define oncotic pressure

The pressure created by the osmotic effects of the solutes

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Define atrioventricular valves

Valves between the atria and the ventricles.

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Define cardiac muscle

Specialised muscle found in the walls of the heart chambers.

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Define semilunar valves

Valves that prevent blood re-entering the heart from the arteries.

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Define myocardial infarction

Heart attack

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Define myofibrils

Microscopic fibres that make up the larger fibres of skeletal muscle

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Define intercalated discs

Gap junctions between the muscle cells in the heart muscle. Enable the muscle cells to fit tightly together and allow synchronised contraction of the heart muscle.

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Define sacromere

The smallest contractile unit of a muscle.

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Define diastole

The relaxing phase of the cardiac cycle.

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Define systole

The phase of the heartbeat when the heart muscle contracts and pumps blood.

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Define bradycardia

A slow heart rhythm

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Define ectopic heartbeat

An extra beat or an early beat of the ventricles.

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Define fibrillation

Uncoordinated contraction of the atria and ventricles.

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Define myogenic muscle

Muscle that can initiate its own contraction.

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Define purkyne tissue

Consists of specially adapted muscle fibres that conduct the wave of excitation from the AVN down the septum to the ventricles.

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Define sino-atrial node (SAN)

The heart's pacemaker. It is a small patch of tissue that sends out waves of electrical excitation at regular intervals in order to initiate contractions.

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Define tachycardia

A rapid heart rhythm.

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Define atrio-ventricular node (AVN)

A patch of tissue, in the heart, at the top of the septum that conducts the excitation wave from the atria to the ventricles.

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Define septum

The wall that separates two heart chambers.

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Define conformational change

A change in the shape of a macromolecule e.g. when oxygen enters haemoglobin

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Define fetal haemoglobin

The haemoglobin found in a foetus that has a higher affinity for oxygen.

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Define carbonic anhydrase

The enzyme that catalyses the combination of carbon dioxide and water.

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Define chloride shift

The movement of chloride ions into the erythrocytes to balance the charge as hydrogen-carbonate ions leave the cell.

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Define bohr effect

The effect that extra carbon dioxide has on the haemoglobin, explaining the release of more oxygen.

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Define dicotyledonous plants

Plants with two seed leaves and a branching pattern of veins in the leaf.

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Define phloem

Tissue that carries products of photosynthesis (assimilates), in solution, within plants.

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Define collenchyma

Cells that have thick cellulose walls and strengthen vascular bundles and outer parts of stems, whilst allowing some flexibility.

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Define sclerenchyma

Plant cells that have lignified walls and are used to strengthen stems and leaf midribs

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Define pericycle

A layer of meristem cells inside the endodermis that can divide.

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Define cambium

The layer of meristem cells between the xylem and phloem in the stem.

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Define companion cells

The cells that help to load sucrose into the sieve tubes

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Define sieve tube elements

Make up the tubes in phloem tissue that carry sap up and down the plant. Separated by sieve plates.

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Define vacuolar pathway

Similar to the symplast pathway but the water can also enter and pass through vacuoles

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Define transpiration

The loss of water vapour through the aerial parts of a plant, mostly through the stomata in the leaves.

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Define hydrophyte

A plant adapted to living in water, or where the ground is wet.

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Define succulent

A plant that stores water in its stem which becomes fleshy and swollen. e.g. Cacti

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Define hydathode

Structures in plants that can release water droplets which may then evaporate from the leaf surface.

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Define assimilates

Substances made by the plant, using substances absorbed by the environment. This includes sucrose and amino acids.

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Define sink

A part of the plant where materials are removed from the transport system. e.g. Fruit or roots. The roots receive sugars and store them as starch.

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Define source

A part of the plant that loads materials into the transport system. e.g. the leaves or roots. Roots when the starch is converted back to sugars and sent to a growing stem.

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Define translocation

The transport of assimilates throughout a plant

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Define active loading

When sucrose is loaded into the sieve tube elements. The companion cell transports out H+ ions. They diffuse back in with sucrose- cotransport. This means that the sucrose conc. is higher in companion cells so the sucrose diffuses into the sieve tube

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Define cotransport

Transport across a cell membrane, using a carrier or channel protein, of two substances moving in the same direction.

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Define pathogen

A disease causing microorganism

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Define mycelium

The vegetative part of a fungus, consisting of a network of fine white filaments.

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Define hyphae

Each of the branching filaments that make up the mycelium of a fungus.

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3 types of disease causing bacteria

Tuberculosis(animal), Bacterial meningitis(animal), Ring rot(plant)

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3 types of disease causing virus

HIV/AIDS(animal), Influenza(animal), Tobacco mosaic virus(plant)

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3 types of disease causing fungus

Ringworm(cattle), Athletes foot(human), Black sigatoka(bananas)

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3 types of disease causing protoctista

Amoebiasis(animal), Malaria(animal), Blight(tomatoes and potatoes)

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Define direct transmission

Passing a pathogen from host to new host, with no intermediary.

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Define indirect transmission

Passing a pathogen from host to new host, via a vector

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Define vector

An organism that carries a pathogen from one host to another (not infected by the disease themselves)

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Define callose

A large polysaccharide deposit that blocks old phloem sieve tubes to prevent the spread of a pathogen (passive defence)

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Define canker

A sunken necrotic lesion in the woody tissue such as the main stem or branch. It causes the death of the cambium tissue in the bark.

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Define mucous membrane

Specialised epithelial tissue that is covered by mucus

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Define primary defences

Those that prevent the pathogen from entering the body.

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Define enzyme cascade

A sequence of successive activation reactions involving enzymes. e.g. blood clotting

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Define histamine

A compound which is released by mast cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries.

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Define antigen-presenting cell

A cell that isolates the antigen from a pathogen and places it on the plasma membrane so that it can be recognised by other cells in the immune system.

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Define clonal selection

Selection of a specific B or T cell that is specific to the antigen.

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Define cytokines

Hormone-like molecules used in cell signalling to stimulate the immune response.

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Define neutrophil

A type of white blood cell that engulfs foreign matter and traps it in a large vacuole (phagosome, which fuses with lysosomes to digest the foreign matter.

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Define opsonins

Proteins that bind to the antigen on a pathogen and then allow phagocytes to bind.

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Define secondary defences

Those that combat the pathogen once they have entered the body.

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Define spore

Highly resistant reproductive structures produced by fungi and some bacteria

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Define tylose

Outgrowth from parenchyma cells into xylem vessels which can block the vessel.

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Define antibody

Specific proteins released by plasma cells that attach to pathogenic antigens

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Define B memory cells/T memory cells

Cells that remain in the blood for long time, providing long-term immunity.

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Define clonal expansion

An increase in the number of cells by mitotic cell division.

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Define interleukins

Signalling molecules that are used to communicate between different white blood cells. They stimulate clonal expansion.

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Define B plasma cells

Derived from B lymphocytes, these are cells that manufacture antibodies.

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Define T helper cells

A cell that produces a releases cytokines

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Define T killer cells

Cells that attack and destroy our own body cells that are infected by a pathogen.

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Define T regulator cells

Cells that are involved with inhibiting or ending the immune response.

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Define agglutinins

Antibodies that cause pathogens to stick together.

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Define anti-toxins

Antibodies that make toxins harmless.

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Define opsonins

Antibodies that make it easier for phagocytes to engulf the pathogen.

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Define active immunity

Where the immune system is activated and manufactures its own antibodies.

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Define artificial immunity

Immunity that is achieved through medical intervention.

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Define natural immunity

Immunity achieved through normal life processes.

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Define passive immunity

Immunity achieved when antibodies are passed to the individual from others.

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Define epidemic

A rapid spread of disease through a high proportion of the population.

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Define pandemic

A worldwide epidemic

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Define vaccination

Stimulating the immune response in order to achieve immunity.

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Define ring vaccination

All people who have been in contact with the patient are vaccinated.

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Define antibiotic

A chemical which prevents the growth of microorganisms. Antibiotics can be antibacterial or antifungal.

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Define personalised medicine

The development of designer medicines for individuals.

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Define synthetic biology

The re-engineering of biology. This could be the production of new molecules that mimic natural processes, or the use of natural molecules to produce new biological systems that do not exist in nature

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Define biodiversity

A measure of the variation found in the living world.

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Define species

A group of organisms that can freely interbreed to produce fertile offspring.

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Formula for mark and recapture technique

C1 x C2 / C3

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Define polymorphic gene locus

A locus that has more than two alleles.

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Define species evenness

A measure of how evenly represented the species are.

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Define species richness

A measure of how many different species are present.

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Define monoculture

A crop consisting of one strain of one species.

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Define selective breeding

The selection of specific traits in plants or animals through breeding programmes.

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Define genetic erosion

A process whereby an already limited gene pool of an endangered species of plant or animal diminishes when individuals from a population die without producing any offspring.

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Define keystone species

One that has a disproportionate effect on its environment relative to its abundance.

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Define soil depletion

The loss of soil fertility caused by removal of minerals due to continuous cropping.

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Define conservation in situ

Carrying out active management to maintain the biodiversity in the natural environment.

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Define conservation ex situ

Conservation outside the normal habitat of the species.

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Define CITES

the Convention on International Trade in Endangered Species

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Define Countryside Stewardship Scheme

A scheme to encourage farmers and other landowners to manage parts of their land in a way that promotes conservation.

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Define binomial system

A system that uses the genus name and the species name to avoid confusion when naming organisms.

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Define phylum

A major subdivision of a kingdom. Contains all the groups of organisms that have the same body plan e.g. a backbone.

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Define class

A group of organisms that all possess the same general traits e.g. number of legs.

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Define order

A subdivision of the class using additional information about the organisms. e.g. carnivorous

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Define family

A group of closely related genera within an order. e.g. dog family

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Define genus

A group of closely related species.

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Define convergent evolution

The process whereby organisms not closely related independently evolve similar traits as a result of being adapted to similar environments or ecological niches.

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Define cytochrome c

An iron-containing protein found within inner mitochondrial membranes. It is genetically different in all species.

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Define phylogeny

The study of the evolutionary relationships between organisms.

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Define artificial classification

Classification based on just one (or a few) characteristic(s).

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Define natural classification

A classification that reflects the evolutionary relationships between organisms.

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Define continuous variation

Variation where there are two extremes and a full range of values in between

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Define discontinuous variation

Where there are distinct categories and nothing in between.

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Define genetic variation

Variation caused by possessing a different combination of alleles.

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Define environmental variation

Variation caused by response to environmental factors such as light intensity.

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Define interspecific variation

The differences between species.

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Define intraspecific variation

The variation between members of the same species.

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Define correlation coefficient

A measure of how closely two sets of data are correlated. A value of 1 means perfect correlation.

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Define student's t-test

A test used to compare two means.

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Define anatomical adaptations

Structural features that promote survival.

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Define behavioural adaptations

The ways that behaviour is modified in order to promote survival.

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Define physiological adaptations

The processes that promote survival.

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