SB1 - Key Concepts in Biology Flashcards
acrosome
A cap-like structure on the head of a sperm cell that contains enzymes used to penetrate an egg cell.
active site
The space in an enzyme where the substrate fits during an enzyme-catalysed reaction.
active transport
The pumping of particles across a membrane (usually from a region of lower concentration to a region of higher concentration, against the concentration gradient). This process requires energy.
adaptations
The features of something that enable it to do a certain function (job).
aerobic respiration
A type of respiration in which oxygen is used to release energy from substances such as glucose.
Benedict’s solution
A solution used to detect the presence of reducing sugars (such as glucose).
biuret test
A test that uses copper sulfate solution and potassium hydroxide solution to test for proteins. The blue of the copper sulfate solution turns purple in the presence of proteins.
biological catalysts
A substance found in living organisms that speed up reactions i.e. an enzyme.
calorimeter
Apparatus used to measure the energy contenof substances by burning them and measuring temperature increase.
catalyst
A substance that speeds up the rate of a reaction without itself being used up.
cell membrane
The membrane that controls what goes in and out of a cell.
cell sap
The liquid found in the permenant vacuole in a plant cell.
cell wall
A tough layer if material around some cells that is used for protection and support. It is stiff and made of celluose in plant cells. Bacteria have a flexible cell wall.
chemical reagents
Substances that are used up in a chemical reaction
chlorophyll
The green substance found inside chloroplasts that traps energy transferred by light.
chloroplasts
A green disc containing chlorophyll found in plant cells. This is where the plant makes glucose through photosynthesis.
chromosomes
A thread-like structure found in a cell. In humans, this DNA is found in chromosomes but the term is also used to describe the large loop of DNA found in bacteria.
cillia
A small hair-like structure on the surface of some cells. Plural is cillia.
cilliated epithelial cells
A cell that lines certain tubes in the body and has cillia on its surface.
concentration gradient
The difference between two concentrations. There will be an overall movement of particles down a concentration gradient, from higher concentration to a lower concentration.
cytoplasm
The watery jelly inside a cell where the cell’s activites take place.
denatured
A denatured enzyme is one where the shape of the active site has changed so much that its substrate no longer fits and the reaction can no longer happen.
diffusion
The random movement and spreading of particles. There is a net diffusion of particles from regions of high oncentration to regions of lower concentrations.
digestion
A process which breaks molecules into smaller, more soluble substances.
diploid
A cell or nucleus that has two sets of chromosomes. In humans, almost all cells except the sperm and egg cells are diploid.
DNA
Deoxyribonucleic acid. A polymer made of deoxyribrose sugar molecules and phosphate groups joined to bases.
egg cell
The female gamete (sex cell).
embryo
The ball of cells produced by cell division of the zygote. A very early stage in the development of a new individual
enzymes
A protein produced by living organisms that acts as a catalyst to speed up the rate of reaction.
epithelial cells
A cell found on the surfaces of internal organs.
ethanol emulsion test
A test using ethanol to detect lipids in food.
eukaryotic
A cell with a nucleus is eukaryotic. Organisms that have cells like this are also said to be eukaryotic organisms.
eyepiece lens
The part of the microscope which you look down.
fertilisation
Fusing of a male gamete with a female gamete.
field of view
The circle of light you see when looking down a microscope,
flagellum
A tail-like structure that rotates, allowing a unicellular organism to move. Plural is flagella.
haploid
A cell of nucleus that has one set of chromosomes. Gametes are haploid.
lock-and-key model
A model that describes the way an enzyme catalyses a reaction when the substrate fits whithin the active site of the enzyme.
magnification
The number of times larger an image is than the inital object that produced it.
microvilli
A tiny fold in the cell surface membrane of a cell. Microvilli are used to increase the surface area of the cell.
mitochondrion
A sub-cellular structure in the cytoplasm of eukaryotic cells wherea erobic respiration occurs. Plural is mitochondria.
monomers
A small molecule that can join with other molecules like itself to form a polymer.
nucleus
The ‘control centre’ of a eukaryotic cell.
objective lens
The part of the microscope that is closest to the specimen.
osmosis
The overall movement of solvent molecules in a solution across a partially permeable membrane, from a dilute solution to a more concentrated one.
oviducts
A tube that carries egg cells from the ovaries to the uterus in females. Fertilisation happens here.
partially permeable
Describes a membrane that will allow certain particles to pass through it but not others. Another term for semi-permeable.
passive
A process that does require energy is passive.
plasmid
A small loop of DNA found in the cytoplasm of bacteria.
polymers
A long-chain molecule made by joining many smaller molecules (monomers) together.
precipitate
An insoluable substance that is formed when two soluble substances react together in solution.
products
A substance formed in a reaction
reducing sugars
Small sugar molecules, such as frutose and glucose, that react with Benedicts’s solution to produce a precipitate.
resolution
The smallest change that can be measured by an instrument. For example in a microscope, it is the smallest distance between two points that cane be seen as two points and not blurred in one point.
ribosomes
A sub-cellular structure that attaches mRNA. It allows tRNA moleucles to match up with the mRNA codons and also joins the amino acids together.
scale bars
A line drawn on a magnified image that shows a certain distance at that magnificatio
solute
Describes a substance that dissolves in a liquid to make a solution.
solvent
Describes the liquid in which a substance dissolveds to make a solution.
specialised cells
A cell that is adapted from a certain specific function (job).
sperm cell
The male gamete (sex cell).
stains
A dye used to colour parts of a cell to make them easier to used.
synthesis
To build a large moleucle from smaller subunits.
vacuole
The membrane -bound space in the cytoplasm of cells. Plant cells have a large permenat vacuole, which stores water and nutrients, and helps to support the plant by kepping the cells rigid.
