Edexcel GCSE (9-1) Biology - Paper 1

haploid

(of a cell or nucleus) containing one set of chromosomes e.g. sperm and egg cells

diploid

(of a cell or nucleus) containing two sets of chromosomes

eukaryotic

(of a cell) containing a nucleus - all animal and plant cells

prokaryotic

(of a cell) not containing a nucleus - bacterial cells

partially/semi-permeable

(of a membrane) allows water molecules (the solvent) to pass through but not the particles of dissolved substances (the solutes)

autotropic

(of an organism) able to live entirely of its own food i.e. it can make organic molecules from inorganic molecules

heterotrophic

(of an organism) needing to consume other organisms for nutrition

enzyme

a biologically catalytic protein that speeds up metabolic processes within living organisms

ciliated epithelial cell

a cell that lines certain tubes in the body and has cilia on its surface

epithelial cell

a cell that lines the surfaces of internal organs in the body

glycerol

a component of lipids that bonds to fatty acid molecules

amino acid

a component of proteins; there are 20 types

slime coat

a feature that some bacteria have - it is a layer outside the cell wall which provides extra protection from extreme environments

zygote

a fertilised ovum (egg cell)

tissue

a group of cells with a similar structure and function e.g. muscle tissue, blood tissue or xylem tissue

lipids

a group of compounds that includes fats and oils, formed of fatty acids bonded to glycerol

organ system

a group of different organs which work together to perform a particular function in a body

carbohydrates

a group of molecules which includes sugars and starches

organ

a group of more than one type of tissue which work together to perform a particular function

cytoplasm

a jelly-like substance filling a cell where most of the chemical reactions occur

eyespot

a light sensitive organelle which some uni-cellular organisms use to find bright light in order to photosynthesise

magnification

a measure of how much bigger the image is compared to the actual size

microvillus (pl. microvilli)

a microscopic fold in the cell surface membrane of a cell which increases the surface area of a cell, for maximum diffusion/absorption

glycogen

a polymer storage material made from glucose

digestion

a process that breaks molecules into smaller, more soluble molecules

metabolic process

a reaction within the body

respiration

a series of enzyme-catalysed reactions occurring in all living cells whereby glucose is broken down to release energy

glucose

a simple sugar produced by the digestion of carbohydrates or by photosynthesis and required for respiration

plasmid

a small loop of DNA found in the cytoplasm of some bacterial cells

acrosome

a small-vacuole that forms a cap-like structure on the head of a sperm cell that contains enzymes used to penetrate an egg cell

permanent vacuole

a space in the centre of plant cells, usually filled with sap to keep the cell turgid

pellicle

a stiff, but slightly flexible, outer layer of some uni-cellular organisms, that can be used to aid movement through water by scrunching and unscrunching

digestive system

a system in mammals to break down food into small molecules and absorb them into the blood

skeletomuscular system

a system in mammals to support the body and allow movement

circulatory system

a system in mammals to transport substances around the body in the blood, consisting of the heart, arteries, veins and capillaries

flagellum

a tail that some cells have to allow them to move e.g. sperm cells, some bacteria or euglena

oviduct

a tube in the female reproductive system that carries egg cells from the ovaries to the uterus, where fertilisation occurs

scientific paper

an article or report written by scientists and published in a scientific journal, often showing the results and conclusions drawn from multiple experiments

carbohydrase

an enzyme group responsible for the break-down of carbohydrates

lipase

an enzyme group responsible for the break-down of lipids

protease

an enzyme group responsible for the break-down of proteins into amino acids

catalase

an enzyme responsible for speeding up the break-down of hydrogen peroxide into oxygen and water

organelle

an individual structure within a cell e.g. a mitochondrion

electron microscope

an instrument that uses a beam of electrons to build up an image of a specimen, which a computer then uses to generate an image using visible light; can achieve magnifications of up to x2 million

light microscope

an instrument with lenses that refract (bend) visible light to magnify images of specimens, to up to around 1500x magnification

contractile vacuole

an organelle which allows cells to expel excess or waste products

proteins

any polymer formed exclusively of amino acid monomers

fatty acids

carboxylic acids that bond to a glycerol molecule to form lipids

formula for total magnification of a light microscope

eyepiece lens magnification x objective lens magnification

formula for magnification

image size / actual size

km

kilometre

m

metre

μm

micrometre (10^-6 equivalent in metres)

mm

millimetre (10^-3 equivalent in metres)

8 characteristics of living organisms

movement respiration sensitivity to stimuli control reproduction excretion nutrition growth & development

nm

nanometre (10^-9 equivalent in metres)

pm

picometre (10^-12 equivalent in metres)

example of active transport in plants

root hair cells using protein pumps to move mineral salts in the soil to inside the cell

cilium (pl. cilia)

small hair-like structure on the surface of some cells that can wave from side to side to sweep substances along; covered by the cell membrane and contain strands of a substance that can contract to cause movement

control

the ability of a living organism to control its internal conditions

sensitivity to stimuli

the ability to detect changes in the environment and respond to them

movement

the characteristic of all living organisms which involves shifting their whole body or parts of it in search of shelter, to find food, to avoid danger and harmful stimuli, to respond to light or gravity, to find a mate or to reproduce

reproduction

the generation of offspring / new individuals

enzyme specificity

the idea that enzymes are specific to their substrate molecule, with an active site which will only be able to act upon the molecule it is designed to

chitin

the key compound found in fungal cell walls

objective lens

the lens closest to the specimen in a light microscope

eyepiece lens

the lens closest to your eye when you look down a light microscope with a standard magnification of 10x

enzyme concentration

the number of enzyme molecules per unit volume of solution of enzyme and substrate

substrate concentration

the number of substrate molecules per unit volume of solution of enzyme and substrate

mitochondrion

the organelle responsible for respiration

nucleus

the organelle that contains the genetic information and controls the activities of the whole cell

net movement

the overall movement of a substance - the movement in one direction minus the movement in the opposite direction

optimum pH

the pH at which an enzyme catalyses a reaction at its fastest

active site

the part of an enzyme which a substrate molecule fits into

stage

the platform on which the slide is placed in a light microscope

Vmax

the point at which the substrate concentration is so high that all enzymes have their active sites full at any given moment and any further increase in substrate concentration would not speed up the reaction

synthesis

the process by which an enzyme bonds substrate molecules in order to form a product molecule

nutrition

the process by which the body takes in and uses food - plants make their own whereas animals need to consume other organisms

mitosis

the process of cells dividing to produce two diploid daughter cells that are genetically identical to the parent

substrate

the reactant acted on by an enzyme

excretion

the removal of toxic waste products from a body e.g. carbon dioxide

product molecules

the resulting molecules after an enzyme has acted upon a substrate

cell wall

the rigid outer layer of cells in plants, fungi and bacteria

slide

the small rectangular glass sheet on which a specimen is placed for viewing in a light microscope

cell

the smallest living unit of a living organism

resolution

the smallest possible change that can be measured by an instrument; in microscopes, it is the smallest distance between two points at which they are still distinct, not blurred into one point

interphase

the stage in the cell cycle during which a cell carries out its functions, prepares itself for cell division, including replicating its DNA and producing additional subcellular structures

enzyme-substrate complex

the state at which a substrate molecule is bonded to the active site of an enzyme molecule

nucleolus

the structure at the centre of a nucleus

nuclear envelope

the surface membrane of the nucleus

optimum temperature

the temperature at which an enzyme catalyses a reaction at its fastest

field of view

the visible circle of light seen when looking through the eyepiece lens of a light microscope

function of muscle tissue

to contract and relax to cause movement

function of connective tissue

to join other tissues together

function of epithelial tissue

to line tubes in the body

function of skeletal tissue

to support and protect the body's delicate organs, and allows movement

function of nerve tissue

to transmit electrical impulses and co-ordinate messages

function of blood tissue

to transport oxygen, digested food molecules and carbon, and to attack pathogens

denaturing

when an enzyme's shape becomes so morphed that it can no longer accept new substrate molecules, caused by extremes of temperature or pH

DNA loop

where the chromosomal DNA is stored in a bacterium; loose in the cytoplasm