Most variation in data gives a bell-shaped frequency distribution called .......
Used to asses how far the values are spread above and below the mean.
Used to find out whether there is a significant difference between the means of two populations.
Functions of life
-Living organisms are composed of cells
-Cells are the smallest units of life
-Cells come from pre-existing cells
Exceptions to the cell theory
How cells in a multicellular organism can develop in different ways.
The whole organism is greater than the sum of it's parts, because of the complex interactions between cells.
Cells that have the capacity to self-renew by cell division and to differentiate.
Surface area to volume ratio
As the size of any object increases, the ratio between the surface area and the volume decreases.
Size of image / size of specimen
A line added to a micrograph or drawing to help show the actual size of the structures.
Prokaryotic cells divide in two by a process called ......
Proteins embedded in the phospholipid bilayer
Proteins on the surface of the membrane.
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.
Diffusion of particles with the aid of channel proteins.
A liquid in which particles dissolve.
The diffusion of water.
The movement of substance across membranes using energy from ATP.
The plant cell wall and glycoproteins are examples of .....
The longest stage in the cell cycle.
During interphase, a period of growth and DNA transcription/ protein synthesis.
During interphase, the period during which all DNA in the nucleus is replicated.
During interphase, the period in which the cell prepares for division.
The process by which the nucleus divides to form two genectically identical nuclei.
The process of splitting the cytoplasm to to form two cells.
4 stages of mitosis
This is formed when cells divide out of control.
The series of events that produces new cells.
Two hydrogen atoms bonded to an oxygen atom.
The type of bond between water molecules and between base pairs in DNA.
Properties of water
Commonest chemical elements of life
Carbon, oxygen, hydrogen, nitrogen
Compounds containing carbon that are found in living organisms.
Compounds that contain no carbon.
Needed to make two of the twenty amino acids that proteins contain.
Helps the body to produce strong bones and teeth.
Part of the phosphate groups in ATP and DNA molecules.
Needed to make cytochromes and oxygen-binding sites on hemoglobin.
Helps with nerve impulses and solute concentrations within cells.
A chain of many amino acids.
Three fatty acids and a glycerol.
The reverse of a condensation reaction.
Examples of monosaccharides
Glucose, galactose, fructose
Examples of disaccharides
Maltose, lactose, sucrose
Examples of polysaccharides
Starch, glycogen, cellulose
Functions of lipids
A sugar, phosphate and base.
Complementary base pairing
A - T
C - G
Each DNA molecule consists of one new strand and one old strand conserved from the parent dna molecule
These store the information for making proteins.
The copying of the base sequence of a gene by making and RNA molecule.
When tRNA creates proteins on a ribosome.
A group of three bases.
Globular proteins which act as catalysts of biological reactions.
Changing the structure of an enzyme or other protein so that it can no longer carry out it's function.
The reactants in reactions catalyzed by enzymes.
A region on the surface of an enzyme to which substrates bind.
Lock and key theory
Theory explaining enzyme specificity.
Factors that affect enzyme activity
Substrate concentration, pH, temperature.
Glucose plus galactose.
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
The study of variation and inheritance
A heritable factor that controls a specific characteristic.
The whole of the genetic information of an organism.
The position of a gene on a chromosome.
A form of a gene.
A change to the base sequence of a gene.
Smallest possible gene mutation when one base is replaced by another base.
Example of a base substitution
Sickle cell anemia
Two full sets of chromosomes.
One set of chromosomes.
Chromosomes that have the same genes as each other, but not necessarily the same alleles.
Meiosis is deceived as a ......
The number and appearance of the chromosomes in an organism.
A sample of amniotic fluid is removed from the amniotic sac for karyotyping.
Chorionic villus sampling
Cells are removed from fetal tissues in the placenta for karyotyping.
Non-separation of chromosomes.
An extra 21st chromosome.
Having two identical alleles of a gene.
Having two different alleles of a gene.
An allele that has the same effect on the phenotype in a heterozygous individual and in a homozygous individual
An allele that only has an effect on the phenotype in a homozygous individual.
When the F1 hybridsroduce gametes, the two alleles separate.
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.
When DNA is copied again and again to produce many copies of the same molecule.
A method of separating mixtures of proteins, DNA or other molecules that are charged.
Genetically modified organisms
Organisms that have genes transferred to them.
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.
The naming of species
Species that are similar are grouped into a ....
Genera that are similar are grouped into a ....
Families that are similar are grouped into an ....
Orders that are similar are grouped into a ....
Classes that are similar are grouped into a .....
Phyla that are similar a grouped into a ....
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
Offspring are produced and added to the population.
Individuals die and are lost from the population.
Individuals move into the area from elsewhere and are added to the population.
Individuals move out of the area to live elsewhere.
(natality + immigration) - (mortality + emigration)
The cumulative change in the heritable characteristics of a population.
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.
Essential for natural selection and therefore for evolution.
Example of evolution in action
Multiple antibioticcresistance in bacteria.
A group of populations living together and interacting with each other in an area.
Position of an organism in the food chain.
Organisms that synthesize their own organic molecules from simple inorganic substances.
Organisms tht obtain organic molecules from other organisms.
3 types of heterotrophs
Consumers, detritivores, saprotrophs
Initial energy source
Organisms that ingest organic matter that is living or recently killed.
Heterotroph that invests dead organic matter.
Heterotroph that lives on or in dead organic matter, secreting enzymes into it and absorbing the products of digestion.
A diagram that shows all the feeding relationships in a community.
Diagrams that show how much energy flows through each trophic level in a community.
A community and it's abiotic environment.
The study of relationships in ecosystems.
Carbon dioxide, methane, oxides of nitrogen, sulfur dioxide.
Heat retention by greenhouse gases in the atmosphere.
Greenhouse effect and it's correlation with rising temperatures on earth.
The environment in which a species normally lives or the location of a living organism.
Source: salivary glands
Source: wall of stomach
Products: small polypeptides
Happens in the small intestine.
After food becomes absorbed, it becomes .....
Structure that absorbs in small intestine.
Mouth, esophagus, stomach, small intestine, large intestine, rectum, anus.
Contraction of the heart is .... Because it can contract on it's own.
Thick layers of circular elastic and muscle fibers, narrow lumen, thick wall to withstand high pressures.
Thin walled, wide lumen, valves to prevent back flow.
Wall consists of a single layer of cells, allows for easy diffusion, very narrow lumen.
Atria contract, blood flows into ventricles, semilunar valves close, ventricles contract, atrioventricular valves close, blood flows into arteries
Composition of blood
Plasma, erythrocytes, leukocytes, playelets.
These cells can identify pathogens and ingest them by endocytosis.
An organism or virus that causes disease.
Functions of blood
Transport and defense against infectious disease
What plasma transports
Nutrients, carbon dioxide, hormones, antibodies, urea.
Barriers to infection
Skin and muscous membranes
Chemicals produced by microorganisms to kill or control the growth of other microorganisms.
Antibodies are made by ....
Caused by the human immunodeficiency virus (HIV)
The process of swapping one gas for another.
The process of bringing fesh air to the alveoli and removing stale air.
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
2 parts to the nervous system
Central nervous system and peripheral nervous system
Neurons that carry impulses from receptors to the central nervous system
Neurons that carry impulses from the central nervous system to effectors.
Neurons that carry impulses within the central nervous system.
A junction between two neurons.
Narrow, fluid -filled space between two neurons.
Chemicals that are passed along the synapse.
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.
When the potential across the membrane is reversed.
When the potential across the membrane is restored.
Maintaining the internal environment of the body between limits.
A rise in levels feeds back to decrease production and reduce this level.
A rise in levels feeds back to increase production and increase this level.
These cells produce insulin.
These cells produce glucagon
A disease in which the contro, of blood glucose does not work effectively and the concentration can rise or fall beyond the normal limits.
FSH and LH are produced by the .....
Stimulates the development of follicles in females.
Fluid-filled sacs that contain and egg cell.
Stimulates follicles to become mature, ovulate and then develop into the corpus luteum.
Male sex hormone.
Short lengths of DNA that are formed between RNA primers.
Uncoils the DNA double helix and splits it into two template strands.
Adds nucleotides in a 5' to 3' direction.
Glues dna fragments back together.
Adds a short length of rna to template strand during DNA replication.
Sequences of bases that are transcribed but nit translated.
Sequences of bases that are transcribed and translated.
Globular structures that contain eight histone proteins, with dna wrapped around it.
The strand if DNA that forms the template.
The strand of DNA that the template is formed from.
Ribosomes in the cytoplasm.
Ribosomes attached to the rough endoplasmic reticulum.
A group of ribosomes moving along the same mRNA as they simultaneously translate it.
3 steps of translation
Initiation, elongation, termination
Primary protein structure
The number and sequence of amino acids in a polypeptide.
Secondary protein structure
Regular peating structures including beta- pleated sheets and alpha- helices.
Tertiary protein structure
The three dimensional conformation if a polypeptide.
Quaternary protein structure
The linking together of two or more polypeptides to form a single protein.
Long and narrow proteins.
Rounded shaped proteins.
Examples of fibrous proteins
Myosin and collagen
Examples of globular proteins
Hemoglobin and immunoglobulin
Induced fit theory
If the shape of an active site alters when substrates bind, several different but similar substrates could bind successfully to it.
Chemicals that reduce the activity of enzymes or even stop it completely.
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
When ATP production relies on energy released by oxidation.
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 that shows that violet and blue light are used most efficiently.
A graph showing the percentage of the wavelengths of visible light that are absorbed by two common forms of chlorophyll.
Wavelengths of light most efficient for photosynthesis
Red and blue wavelengths
An electron at a higher energy level.
Where chlorophyll is located.
The production of ATP using the energy from an excited electron from photosystem 2.
The splitting of water molecules during photosynthesis.
The product of photolysis.
Essential substrate in the light-independent reactions.
Light-dependent and light - independent reactions
Two reactions in photosynthesis.
Limiting factors of photosynthesis
Light intensity, carbon dioxide concentration, temperature.
Densely packed cylindrical cells with many chloroplasts.
The loss of water vapour from the leaves and stems of plants.
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.
Pair of cells that can open or close the stoma.
Brings water to replace losses due to transpiration.
Transports products if photosynthesis out of the leaf.
This hormone causes guard cells to close the stomata.
Factors that effect transpiration rate
Light, temperature, humidity, wind
Plants that are adapted to grow in very dry habitats.
They absorb water and mineral ions from the soil.
When transpiration is occurring, water moves upwards from the roots to the leaves.
Low pressure or suctn is created inside xylem vessels when water is pulled out.
When sugars and amino acids are transported inside plants via phloem tissue.
Source to sink
Sugar and amino acids are transported through the phloem from ..... to ......
The transfer of pollen from an anther to a stigma.
Male part of a flower
Female part of a flower
Holds up anthers.
Holds up stigma.
Factors need fir seed germination
Water, oxygen, suitable temperatures
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.
The leaves the the embryo plant has.
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.
Regions in plants where cells continue to divide and grow.
Meristems at the tip of the root and the tip of the stem. Allows for elongation.
Usually the cambium in a dicotyledon plant. Allows for growth in girth.
A plant hormone which acts as a growth promoter.
A pigment in leaves which exists in two forms that allows the plant to measure the lengths of periods of darkness.
Ratio for heterozygous dihybrid cross
Ratio for heterozygous monohybrid cross
Characteristics that are influenced by more than one gene.
When some pairs of genes do not follow the law of independent assortment and combinations if genes tend to be inherited together.
While the chromosomes are paired during meiosis, sections of chromatid are exchanged.
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.
Resistance to infection.
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.
Small cell fragments that circulate with erythrocytes and leukocytes in the blood plasma.
These attach muscle to bone.
These provide a firm anchorage for muscles.
These connect bone to bone.
This reduces friction between bones where they meet.
This lubricates the joint to reduce friction.
This seals the joint and holds in the synovial fluid.
Within each muscle fibre a cylindrical structures called .....
Subunit of a myofibril.
The part of the sarcomere containing myosin.
The part of the sarcomere containing actin.
Thin muscle filaments.
Thick muscle filament with heads.
The places where actin and myosin are attached.
Functions of the kidney
Excretion and osmoregulation.
The removal from the body of the waste products of metabolic pathways.
The control of the water balance of the blood, tissue or cytoplasm of w living organism.
The production of filtrate from blood.
The functional unit of the kidney.
This mostly happens in the proximal convoluted tubule
The production of spermatozoa. (4)
Spermatogenesis occurs here.
These cells secrete testosterone
The production of an ovum. Occurs in the ovary. Produces one good ova and 3 polar bodies.
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.
Biological term for sexual intercourse.
The fusion of an egg with a sperm.
The end of pregnancy is signal led by the fall of this hormone.
This hormone causes the muscle in the uterus wall to contract and acts on a positive feedback loop.
When contractions continue for a time after birth to expel the placenta.
This acts as a shock absorber for the baby in the womb.
This hormone prevents the degeneration of the corpus luteum.
The lining of the uterus into which the placenta grows.
A change in the environment, either internal or external, that is detected by a receptor and elicits a response.
A change in an organism produced by a stimulus.
A rapid, unconscious response to a stimulus.
Hair cells in the cochlea of the ear or pressure receptor cells in the skin.
Receptor cells in the tongue or nerve endings in the nose.
Nerve endings in the skin to detect warm or cold.
Rod and cone cells in the eye.
Passage of sound
Eardrum, bones of the middle ear, oval window, hair cells in the cochlea.
Processing of visual stimuli
Convergence, edge enhancement, contralateral processing.
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.
Nicotine, cocaine, amphetamines
Bezodiazepines, alcohol, THC
Reasons for addiction to psychoactive drugs
Dopamine secretion, genetic predisposition, social factors.
Controls automatic and homeostatic activities such as digestion, breathing and heart activity
Coordinates unconscious functions such as balance and movements.
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.
Sympathetic nervous system
Fight, flight and fright nervous system.
Parasympathetic nervous system
Restores body to regular functioning order
When animals search for food.
Actions that increase another individuals lifetime number of offspring at a cost to ones own survival and reproduction.
Chemical messengers, secreted by endocrine glands directly into the blood.
This hormone causes a reduction in the concentration of the blood plasma by stimulating the kidney to produce hypertonic urine.
One group of secretory cells, clustered around the end of a duct.
Content of saliva
Salivary amylase, mucous
Pepsinogen, hydrochloric acid, muscous
Pancreatic amylase, pancreatic lipase, phospholipase, trypsinogen, carboxypeptidase, alkaline fluid
Inactive form of pepsin, activated by hydrochloric acid.
Inactive form of trypsin, activated by enterokinase
An acid-tolerant bacterium that infects the lining of the stomach.
This is secreted by the liver and stored in the gallbladder.
The breakdown if fats into smaller pieces aided by bile.
Digested foods are mainly absorbed in this part of the small intestine.
Protrusions of the free surface of the plasma membrane into the lumen of the ileum
Small vesicles, especially near the microvilli.
Largest organ in the human abdomen.
Hepatic portal vein and hepatic artery
The liver is supplied with blood by these two vessels.
Vessels that the hepatic portal vein has divided up into.
Roles of the liver
Nutrient storage and regulation, breakdown of erythrocytes, synthesis of plasma proteins, synthesis of cholesterol, detoxification.
Contraction of the chambers of the heart.
Relaxation of the chambers of the heart.
Degenerative disease of large and medium sized arteries.
The formation of clots
Pressures exerted by each of the gases in a mixture of gases.
The release of oxygen by hemoglobin in respiring tissues is promoted by this effect.
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.
Normal pH of blood.
Fibrin + red blood cells
Platelets and damaged cells release these.
This is activated by clotting factors. Inactive form is prothrombin.
This is activated by thrombin. Inactive form fibrinogen.
Fibrins inactive form.
Thrombins inactive form.
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.
The lymph nodes carry a large variety of these lymphocytes.
Also know as cytotoxic cells.
Immunity due to infection.
Immunity due to inoculation with vaccines.