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Most variation in data gives a bell-shaped frequency distribution called .......
Used to find out whether there is a significant difference between the means of two populations.
-Living organisms are composed of cells
-Cells are the smallest units of life
-Cells come from pre-existing cells
The whole organism is greater than the sum of it's parts, because of the complex interactions between cells.
Surface area to volume ratio
As the size of any object increases, the ratio between the surface area and the volume decreases.
This allows membranes to change shape in a way that would be impossible if they were solid.
Hormone binding sites
A site exposed on the outside of the membrane that allows one specific hormone to bind.
The passive movement of particles from a region of high concentration to a region of low concentration.
Each DNA molecule consists of one new strand and one old strand conserved from the parent dna molecule
Changing the structure of an enzyme or other protein so that it can no longer carry out it's function.
A controlled release of energy, in the form of ATP, from organic compounds in cells.
Measuring rates of photosynthesis
-production of oxygen
-uptake of carbon dioxide
-increases in biomass
Chromosomes that have the same genes as each other, but not necessarily the same alleles.
An allele that has the same effect on the phenotype in a heterozygous individual and in a homozygous individual
The association of a characteristic with gender, because the gene controlling the characteristic is located on a sex chromosome.
When a person has a recessive of an allele of a gene but it does not affect the phenotype because a dominant allele is also present.
An individual that might be heterozygous is crossed with an individual that is homozygous recessive.
A method of separating mixtures of proteins, DNA or other molecules that are charged.
A group of genetically identical organisms or a group of genetically identical cells derived from a single parent cell.
A group of organisms with similar characteristics which can interbreed and produce fertile offspring.
No clear symmetry, attached to a surface, pores through body, no mouth or anus
Bilaterally symmetric, flat bodies, unsegmented, mouth but no anus
i.e. Planaria, tapeworms, liverflukes
Muscular foot and mantle, shell usually present, segmentation not visible, mouth and anus
i.e. Slugs, snails, clams, squids
Radially symmetric, tentacles, stinging cells, mouth but no anus
i.e. Jellyfish, corals, sea anemones
Bilaterally symmetric, bristles often present, segemented, mouth and anus
i.e. Earthworms, leeches, ragworms
Bilaterally symmetrical, exoskeleton, segmented, jointed appendages
i.e. Insects, spiders, crabs, milipedes
Evidence for evolution
Homologous anatomical structures, fossil records, selective breeding of domesticated animals.
The better adapted individuals tend to survive and reproduce more than the less well-adapted individuals.
Heterotroph that lives on or in dead organic matter, secreting enzymes into it and absorbing the products of digestion.
Thick layers of circular elastic and muscle fibers, narrow lumen, thick wall to withstand high pressures.
Atria contract, blood flows into ventricles, semilunar valves close, ventricles contract, atrioventricular valves close, blood flows into arteries
Chemicals produced by microorganisms to kill or control the growth of other microorganisms.
Adaptations of the alveolus
Huge surface area for gas exchange, wall consists of thin layer of cells, covered by capillaries, surfactant is released to allow gases to dissolve.
External intercostal muscles contract,diaphragm contracts, volume in thorax is increased, pressure drops, air flows in.
Internal intercostal muscles contract, abdominal muscles contract, volume of thorax is decreased, pressure is increased, air flows out
Stages in synaptic transmission
Nerve impulse reaches end of pre-synaptic neuron, calcium diffused in through calcium channels, vesicles of neurotransmitters move to membrane and release their contents, neurotransmitters diffuse across synaptic cleft and binds to receptors, sodium ions enter post-synaptic neuron and cause depolarization, nerve impulse sets off along the post synaptic neuron, calcium is pumped out of pre-synaptic neuron and maiming neurotransmitters are broken down or absorbed.
The electrical potential across the plasma membrane of a cell that is not conducting an impulse.
The reversal and restoration of the electrical potential across the plasma membrane of a cell, as an electrical impulse passes along it.
A disease in which the contro, of blood glucose does not work effectively and the concentration can rise or fall beyond the normal limits.
Secondary protein structure
Regular peating structures including beta- pleated sheets and alpha- helices.
Quaternary protein structure
The linking together of two or more polypeptides to form a single protein.
Induced fit theory
If the shape of an active site alters when substrates bind, several different but similar substrates could bind successfully to it.
substrate and inhibitor are chemically similar, inhibitor binds to active site, prevents the substrate from binding to enzyme therefore the activity of the enzyme is prevented.
Substrate and inhibitor are not similar, inhibitor binds to enzyme at different site, inhibitor changes conformation of enzyme but substrate may still be able to bind to active site
The product of the last reaction in the pathway inhibits the enzyme that catalyzed the first reaction.
Enzymes that have two non-overlapping binding sites, one of which is the active site.
One glucose is converted into two pyruvate, there is a net yield of 2 ATP molecules, 2 NAD+ are converted into 2 NADH + H+
Pyruvate from glycolysis is absorbed by the mitochondrion, oxidative decarboxylation occurs on pyruvate and Acetyl CoA is produced.
Acetyl CoA is transferred to oxaloacetate to form citrate which is eventually turned back to oxaloacetate. Cycle happens twice and yields 2 ATP
The coupling of ATP synthesis to electron transport via a concentration gradient of protons.
Electron transport chain
Located in mitochondrial inner membrane, NADH and FADH2 feed electrons into the chain, at the end of the chain, the remaining electrons are given to oxygen. Oxygen accepts these electrons as well as hydrogen ions to create water and yields 30 ATP. The only stage in cellular respiration that uses oxygen.
Located in the inner mitochondrial membrane, it transports the protons back across the membrane down the concentration gradient.
The process that plants, algae and some bacteria use to produce all of the organic compounds that they need.
A graph showing the percentage of the wavelengths of visible light that are absorbed by two common forms of chlorophyll.
The production of ATP using the energy from an excited electron from photosystem 2.
Consists of loosely packed cell with few chloroplasts. Provides main gas exchange surface in plants.
Pores that allow carbon dioxide to flow into the plant and oxygen to flow out. Normally found on the underside of the leaf.
When transpiration is occurring, water moves upwards from the roots to the leaves.
Steps of germination
Absorption of water, production of gibberellin in cotyledons, gibberellin stimulates production of amylase,amylase catalyses digestion of starch into maltose, maltose converted inti glucose which provides the seed with energy.
Characteristics of a monocotyledon plant
Leaf veins run parallel, vascular bundles in stem are spread randomly, organs of flower in multiples of 3, unbranched roots.
Characteristics of a dicotyledon plant
Leaf veins in net-like pattern, vascular bundles are in ring in stem, organs in multiples of 4 or 5, branched roots.
A pigment in leaves which exists in two forms that allows the plant to measure the lengths of periods of darkness.
When some pairs of genes do not follow the law of independent assortment and combinations if genes tend to be inherited together.
Involves two divisions to form four cells, chromosome number is halved, the is an almost infinite amount of genetic variety.
8 stages of meiosis
Prophase1, metaphase1, anaphase 1, telophase 1, prophase 2, metaphase 2, anaphase2, telophase 2.
Stages in antibody production
Antigen presentation, activation of helper T-cells, activation of B-cells, production of plasma cells, production of memory cells
Macrophages take in antigens by endocytosis, process them and the attach them to membrane proteins called MHC proteins. The antigens are then displayed on the outside if the macrophage.
Activation of helper T-cells
Helper T-cells have receptors that can bind to antigens presented by macrophages. The helper T-cells bind to the antigens and the macrophage passes a signal to them changing them from inactive to active.
Activation of b-cells
The activated helper T-cell sends a signal to the b-cell causing it to change from inactive to active.
Due to the production of antibodies by the organism itself after the body's defense mechanisms have been stimulated by antigens.
Due to the acquisition of antibodies received from another organism, in which active immunity has been stimulated.
The control of the water balance of the blood, tissue or cytoplasm of w living organism.
Stages in the fertilization of a human egg
Arrival of sperm, binding, acrosome reaction, fusion, cortical reaction, mitosis.
When the contents of the acrosome are released and proteases digest a route for the sperm.
Cortical granules move to the plasma membrane of the egg and fuse with it. Enzymes are released and prevents the entry of more sperm.
This hormone causes the muscle in the uterus wall to contract and acts on a positive feedback loop.
A change in the environment, either internal or external, that is detected by a receptor and elicits a response.
Bipolar cells in the retina combine the impulses from groups of rod or cone cells and pass them on to ganglion cells.
When the left and right optic nerves meet at a structure called the optic chiasma.
Neurotransmitter released by the presynaptic neuron causes depolarization and an action potential in the postsynaptic neuron. Postsynaptic transmission is therefore excited.
Neurotransmitter released by presynaptic neuron makes postsynaptic neuron hyper polarized therefore transmission is inhibited.
Reasons for addiction to psychoactive drugs
Dopamine secretion, genetic predisposition, social factors.
Controls automatic and homeostatic activities such as digestion, breathing and heart activity
Maintains homeostasis, produces hormones and sends releasing factors to stimulate secretion by the pituitary gland
Posterior lobe stores and secretes hormones produced by the hypothalamus; anterior lobe produces and secretes hormones that regulate many bodily functions.
Receives impulses from eye, ear, nose and tongue; acts as integrating center fornhigher complex functions.
Autonomic nervous system
The part of the nervous system that is used to control internal processes unconsciously.
Actions that increase another individuals lifetime number of offspring at a cost to ones own survival and reproduction.
This hormone causes a reduction in the concentration of the blood plasma by stimulating the kidney to produce hypertonic urine.
Pancreatic amylase, pancreatic lipase, phospholipase, trypsinogen, carboxypeptidase, alkaline fluid
Roles of the liver
Nutrient storage and regulation, breakdown of erythrocytes, synthesis of plasma proteins, synthesis of cholesterol, detoxification.
When a carrier protein is used that simultaneously moves a chloride ion into the red blood cell, therefore preventing the balance of charges across the membrane to be altered.
In repairing tissues, carbon dioxide binds reversibly to hemoglobin to form this.
Cells in the walls of arteries which monitor blood pH and concentrations of oxygen and carbon dioxide in the blood.
Clotting factors, prothrombin, thrombin, fibrinogen, fibrin, fibrin + red blood cells to give clot.
These molecules found on the outside on antigens are recognized by leukocytes and triggers an immune response.
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