Biology Unit 2 Revision cards

  • Created by: Alisha
  • Created on: 13-07-14 16:08
Intraspecific variation
When members of the same species differ from each other
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Interspecific variation
If one species differs from another
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Average value found by adding the values and dividing by the number of values
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Random sampling
Method of sampling where numbers are picked using a random number generator or grid and take samples where coordinates are generated
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Sampling Bias
When investigators make unrepresentative choices (deliberately or by accident) making the selection process biased
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Standard deviation
Average distance of values from the mean
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Normal distribution curve
Bell shaped curve where data either side of the mean is symmetrical
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Basic DNA component made up of a sugar (deoxyribose) a phosphate group and an organic base
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Double ring organic base which pairs which thymine
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Double ring base which pairs with cytosine
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Single ring organic base which pairs with adenine
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Single ring organic base which pairs with Guanine
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Condensation reaction
Chemical process in which two molecules are combined to form a more complex one by the elimination of a water molecule
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Structure made of protein and DNA by which hereditary information is physically passed from one generation to another
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One of the two copies of the chromosomes that are joined together by a single centromere prior to cell division
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Hydrogen bonds
Chemical formed between positive charge on hydrogen atom and negative charge on another atom of an adjacent molecule
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Double helix
Structure of DNA, two twisted polynucleotide chains
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Section of DNA on a chromosome coding for one or more polypeptides
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Triplet code
Code for an amino acid
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Point holding together two chromatids
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Homologous Pair
Pair of chromosomes one from the mother and one from the father
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Half the number of normal chromosomes
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Total number of homologous pairs
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One of the number of alternative forms of a gene
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The type of nuclear division in which the number of chromosomes is halved, produces four daughter nuclei
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The position of a gene on a chromosome or DNA molecule
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Reproductive (sex) cell that fuses with another during fertilisation
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Genetic recombination
The process of forming new allelic combinations in offspring by exchanes between genetic materials as exchange of DNA sequences between DNA molecules
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Independent segregation
The process of random segregation and assortment of chromosomes during anaphase of meiosis resulting in the production of genetically unique gametes
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Selective breeding
AKA artificial selection, identifying individuals with desired characteristics and using them to parent the next generation
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Genetic diversity
Variety of genes possessed by individuals which make up a species
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The founder effect
When a few individuals from a population colonise a new region. The individuals carry only a small fraction of the total alleles therefore a new population will show less genetic diversity than the population they came from.
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Genetic bottlenecks
When a population suffers a dramatic drop in numbers. The survivors will have fewer alleles than the previous population so when they recolonise, the reestablished population will have less genetic diversity.
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Insoluble polysaccharide made of chains of a glucose, found in plants and used for storage and transport
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Insoluble, highly branched polysaccharide made of chains of a glucose and found in animals and used for storage
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Insoluble polysaccharide found in plants and used for strength (in cell walls) and made of b glucose molecules
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Leaf Palisade cell
Typical plant cell whose function is to carry out photosynthesis
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Cell wall
Organelle of a plant cell consisting of cellulose microfibrils whose function is to provide strength in order to prevent cell bursting when water enters by osmosis
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Organelles in plant cells which carry out photosythesis
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Chloroplast envelope
Double plasma membrane surrounding chloroplast which controls what enters and exits
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Photosynthetic pigment
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Stacks of thylakoids (found in chloroplast) where the 1st stage of photosynthesis happens
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Disc like structure which contains chlorophyll
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Middle lamella
Thin layer which marks the boundary between adjacent cell walls and enters and cements adjacent cells together
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Fluid filled matrix where second stage of photosynthesis takes place
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Ability to retain oxygen
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Haemoglobin combining or loading/releasing or unloading oxygen
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Protein molecules consisting of four polypeptide chains which transport O2
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Oxygen dissociation curve
Graph of the relationship between partial pressure of oxygen (kPa) and saturation of haemoglobin
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Nuclear division
Process by which the nucleus divides. There are two types mitosis and meiosis
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Cell division
Follows nuclear division when the whole cell divides
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The type of nuclear division in which two daughter cells are produced with the same number of chromosomes and the parent cell
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Semi conservation replication
The process of DNA synthesis in which two original strands of the molecule seperate and act as a template on which a new complementary strand is laid down.
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Phase which occupies most of the cell cycle, no division takes place but protein sys
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Phase when chromosomes arrange themselves at the centre of the cell
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Phase where each of the two threads of a chromosomes (chromatid) migrates to an opposite pole
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Phase when nuclear envelope reforms
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DNA Helicase
Enzyme which breaks the hydrogen bonds linking the base pairs of the DNA
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DNA Polymerase
Enzyme which joins together activated nucleotides
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When cells become specialized in structure to suit the role it will carry out
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Collection of similar cells that perform a specific function
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Combination of tissues that are coordinated to perform a variety of functions although they have one main function
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Organ system
Organs work together as a single unit, this is known as an organ system
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Movement of molecules or ions from a region where they are in high concentration to one where their concentration is lower
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The passage of water from a region of high water potential to an area where the water potential is lower through a partially permeable membrane
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Active transport
Movement of a substance against a concentration gradient, process requires energy in the form of ATP
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Internal network of tubes which extend throughout the tissue of an insect for gas exchange
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Tiny pores in which gas leaves and enters the tracheae of an insect
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Gill filaments
Thread like processes which make up the surface of the gill
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Gill lamellae
Thin plates of bone which are at right angles to the filaments which increase the surface area of the gills
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Counter current flow
Flow of the water over the gill lamellae and flow of blood within them are in opposite directions
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Structure in veins which ensures blood flows the right way
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Central cavity of blood vessel through which blood flows
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Carry blood from capillaries back to the heart
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Carry blood away from the heart to the arterioles
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Smaller arteries that control blood flow from the arteries to capillaries
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Tiny vessels linking arterioles to veins
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Pulmonary artery
Carries deoxygenated blood from the heart to the lungs
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Carries oxygenated blood from the heart to the rest of the body
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Vena Cava
Carries deoxygenated blood to the heart from the rest of the body
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Pulmonary Vein
Carries oxygenated blood from lungs to the heart
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Renal artery
Carries oxygenated blood towards kidney
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Hepatic artery
Carries oxygenated blood towards the liver
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Hepatic portal vein
Carried deoxygenated blood from the stomach and intestines to the liver
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Renal vein
Carries deoxygenated blood away from kidney
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Hepatic Vein
Carries deoxygenated blood away from the liver
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Hydrostatic pressure
Pressure exerted by a fluid
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Tissue fluid
Watery liquid which supplies all substances to the tissues and receives carbon dioxide and other waste materials from them
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Lymph/lymphatic system
(contents of) system which returns tissue fluid back to the bloodstream
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Filtration assisted by blood pressure e.g. the formation of tissue fluid
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Evaporation of water from the plant
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Water potential
The pressure created by water molecules. Measure of the extent to which the solution gives out water. The higher the no of molecules the higher the water potential.
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Attraction of molecules of the same type
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Route through the cell walls and intercellular spaces of plants by which water and dissolved substances are transported
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Route through the cytoplasm and plasmodesmata of plant cells which water and dissolved substances are transported
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Root hair
Exchange surface in plants responsible for the absorption of water and mineral ions
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Small pores found on the lower epidermis of the leaf, surrounded by guard cells which open and close the pore to control the rate of gas exchange
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Casparian *****
Distinctive band of suberin around the endodermal cells of a plant root that prevent water passing into the xylem via the cell walls, water is forced through the protoplast of the endodermal cells
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Dead, hollow, elongated tubes with lignified side walls and no end walls that transport water in plants
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Tissue in a plant whose functions are transporting organic food molecules (e.g. sucrose) from the leaf to the rest of the plant
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The single inner layer of cells in the cortex of a root, surrounding vascular bundle (phloem and xylem)
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Outer layer of tissue below epidermis of root
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Transpiration pull
Water being pulled up the xylem as a result of transpiration
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Cohension tension theory
The hypothesis used to explain how water can travel upwards against gravity in the plant. Transpiration puts the xylem under tension and water is pulled up due to cohesive properties.
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Xerophytic plants
Plants adapted to living in areas where their water losses due to transpiration may exceed their water uptake.
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Group of similar organisms that can breed to product fertile offspring
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Ecological niche
Describes how an organism fits into its environment, what it is like, where it is, how it behaves, its interaction with other species and how it responds to its environment.
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Gene pool
The total number of alleles in a particular population at a specific time
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Binomial system
System where two names are used to identify species
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Generic/specific name
Generic - denotes genus, specific - donates species
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Grouping of organisms
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Study of groups of organisms and the positions in hierarchical order
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Artificial classification
Divides organisms according to differences useful at the time e.g. wings, size, colour...
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Natural classification
Groups using shared features derived from ancestors, evolutionary relationships between organisms and ancestors and arranges groups in hierarchy where there is no overlap.
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Evolutionary relationship between organisms
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DNA hybridization
Technique used to study relationships between organisms. Where DNA strands are combined to make a hybrid strand. The higher the temperature needed to break apart the strand the more complementary bases and hydrogen bonds and the more closely related
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Immunological comparison of proteins
Technique used to study relationships between organisms. Where antibodies of one species will respond to specific antigens on proteins. The more precipitate formed the more closely related the species.
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Courtship behaviour
Behaviour used by organisms to recognize members of the same species, idenitfy a mate capable of breeding, form a pair bond and synchronize mating
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By process of natural selection organisms adjust to suit the changing environment in which they live
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Prokaryotic Cell
Cells with no distinct nucleus or membrane bound organelles
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Eukaryotic cells
Cell with distinct nucleus and chromosomes and membraned organelles
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Changes in DNA which result in different characteristics
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When one bacterial cell transfers DNA to another
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Horizontal gene transmission
Genes passed from one species to another
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Vertical gene transmission
Genes are passed from one generation of a species to the next generation of the same species
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a medicine which inhibits the growth of microorganisms
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Antibiotic resistance
The development in microorganisms of mechanisms that prevent antibiotics from killing them.
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Osmotic lysis
Entry of water by osmosis causes the cell to burst
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Small circular piece of DNA found in bacterial cells
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Term used to describe variety in the living world, refers to the number and variety of living organisms in a particular area.
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Species diversity
Number of different species and number of individuals of each species within one community
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Genetic diversity
Variety of genes possessed by individuals that make up the species
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Ecosystem diversity
Range of different habitats within a particular area
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All the living organisms present in an ecosystem at a given time
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Place where an organism normally lives and which is characterized by physical conditions and types of other organisms present
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Species diversity index
Measurement of species diversity (look up equation)
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Other cards in this set

Card 2


Interspecific variation


If one species differs from another

Card 3




Preview of the front of card 3

Card 4


Random sampling


Preview of the front of card 4

Card 5


Sampling Bias


Preview of the front of card 5
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