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IB Higher Biology
Revision of some of the material covered in our classes.
85
Biology
Not Applicable
05/08/2013

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Cards

Term
Abiotic Factor
Definition
A non-biological factor that is a part of the environment of an organism.
Term
Absorption Spectrum
Definition
The range of a pigment's ability to absorb various wavelengths of light.[image]
Term
Action Potential
Definition
The rapid change (depolarisation) in membrane potential of an excitable cell (e.g.: A neurone)
Term
Action Spectrum
Definition

The range of wavelengths of light in which a process such as photosynthesis can take place.

[image]

Term
Activation Energy
Definition
The energy a substrate molecule must have before it can undergo a chemical change.
Term
Active Site
Definition
The region of an enzyme to which the substrate molecule binds itself
Term
Active Transport
Definition
Movement of substances across membranes involving a carrier protein and ATP
Term
Aerobic Respiration
Definition
Respiration requiring oxygen, involving the oxidisation of glucose to carbon dioxide and water
Term
Alimentary Canal
Definition
The gut; a tube running from the mouthto the anus in vertebrates, where complex food substances are digested and the products of digestion selectively absorbed into the body.
Term
Allele
Definition
An alternative form of a gene occupying a specific locus on a chromosome.
Term
Allele Frequency
Definition
The commonness of the occurenceof any particlular allele in a population.
Term
Alveolus
Definition
Air sac in the lung.
Term
Amino Acid
Definition
Building block of proteins; general formula: 

R.CH(NH2).COOH
Term
Anabolism
Definition
The building up of complex molecules from smaller ones.
Term
Anaerobic Respiration
Definition
Respiration in the absence of oxygen, involving breakdown of glucose to lactic acid or ethanol.
Term
Anion
Definition
An ion with a negative charge.
Term
Antibody
Definition
A protein produced by bloodplasma cells derived from B lymphocytes when in the presense of s pecific antigen, which then binds with the antigen, aiding it's destruction.[image]
Term
Anticodon
Definition
Three conswecutive bases in tRNA, complementary to a codon on RNA.
Term
Antiduiretic Hormone (ADH)
Definition
Hormone secreted by the pituitary gland that controls the permeability of the walls of the collecting ducts of the kidney.
Term
Antigen
Definition

A substance capable of binding specifically to an antibody.

[image]

Term
Asexual reproduction
Definition
Reproduction not requiring gametes or fertilisation.
Term
Assimilation
Definition
The uptake of nutrients into cells and tissues.
Term
Atherosclerosis
Definition
The deposition of cholestrol derivative plaque on inner wall  of blood vessels.[image]
Term
Atrio-ventricular node
Definition

Mass of tissue in the wall of the right atrium, functionally part of the pacemaker mechanism.

[image]

Term
Atrio-ventricular valve
Definition

Tricuspid or bicuspid valve.

[image]

Term
Atrium
Definition

One of the two upper chambers of the mammalian four chambered heart.

[image]

Term
Autotroph
Definition
self-feeding; ableto synthesise it's own elaborated foods from simpler substances.
Term
Axon
Definition
Fibre carrying impulses away from the cell body of a neurone.
Term
Bicuspid Valve
Definition
Valve between atrium and ventricle on the left side of the mammalian heart.
Term
Binary fission
Definition
When a cell divides into two daughter cells, typically in the reproduction of prokaryotes.
Term
Biomagnification
Definition
The process by which chemical substances become more concentrated at each trophic level.
Term
Biome
Definition
A major life-zone oover an area of the Earth, characterised by the dominant plant life present.
Term
Biotic factor
Definition
The influence of living things on the environment of other living things.
Term
Bivalent
Definition
A pair of duplicated chromosomes, held together by chiasmata during meiosis.
Term
Bronchiole
Definition
Small terminal branch of a bronchus.
Term
Bronchus
Definition
A tube connecting the trachea with the lungs.
Term
Calvin Cycle
Definition
A cycle of reactions in the stroma of the chloroplast by which some of the product of the dark reaction if reformed as the acceptor molecule for CO(ribulose biphosphate).
Term
Carrier
Definition
An individual that has one copy of the recessive allele that causes a genetic disease in individuals who are homozygous for this allele.
Term
Carrier protein
Definition
One of the types of protein present in plasma membranes responsible for active transport across membranes.
Term
Cardiac Cycle
Definition
The stages of the heart beat,by which the atrial and then the ventrical walls alternately contract (systole) and relax (diastole).
Term
Catabolism
Definition
The breaking down of complex molecules in the biochemistry of cells.
Term
Catalyst
Definition
A substance that alters the rate of a chemical reaction, but remains unchanged at the end.
Term
Central Dogma
Definition
The idea that transfer of genetic information from DNA of the chromosome to mRNA to protein (amino acid sequence) is irreversible.
Term
Centromere
Definition
Constriction of the chromosome; the region that becomes attached to the spindle fibres in division.
Term
Centrosome
Definition
Organelle situated near the nucleus in animal cells, involved in the formation of the spindle prior to nuclear division.
Term
Chiasma
Definition
The site where crossing over of segments of DNA occurs.
Term
Chloroplast
Definition
Organelle that is the site of photosynthesic pigment of green plants, and contains chlorophyll.
Term
Chlorophyll
Definition
The main photosynthetic pigment of green plants,
Term
Chlorophyll
Definition
The main photosynthetic pigment of green plants; occurs in the grana membranes of the chloroplasts.
Term
Cholestrol
Definition
A lipid of animal plasma membranes transported in the blood as lipoprotein.
Term
Chromatid
Definition
One of two copis of a chromosome after replication.
Term
Chromatin
Definition
A nuclear protein material in the nucleus of eukaryotic cells at interphase; forms into chromosomes during mitosis and meiosis.
Term
Chromosome
Definition
Visible in appropriately stained cells at nuclear devision, each chromosome consists of a long thread of DNA packaged with protein; chromosomes replicate prior to, into chromatids. Contents of nucleus appears as granular chromatin between divisions
Term
Zygote
Definition
product of the fusion of gametes
Term
Virus
Definition
Minute, intracellular parasite, formed of protein and nucleic acid
Term
Vesicle
Definition
Membrane-bound sac (used in bulk transport)
Term
Ventricle
Definition
Chamber, either of the centre of the brain, or of the heart (the bottom two chambers)
Term
Vein
Definition
Vessel that returns blood to the heart
Term
Vector
Definition
an organism that transmits a disease-causing organism, or a device for transferring genes during genetic engineering
Term
Vasodilation
Definition
dilation of blood supply to capillaries (of skin)
Term
Vasoconstriction
Definition
constriction of blood supply to capillaries (of skin)
Term
Vacuole
Definition
fluid-filled space in the cytoplasm, especially large and permanent in plant cells
Term
Vaccination
Definition
conferring immunity from a disease by injecting an antigen (of attenuated microorganisms or inactivated component) so that the body acquires antibodies prior to potential infection
Term
Uric acid
Definition
an insoluble purine, formed from the breakdown of nucleic acids and proteins
Term
Unsaturated fat
Definition
lipid with double bond(s) in the hydrocarbon chain
Term
Turgid
Definition
having high internal pressure
Term
Trophic level
Definition
a level in a food chain defined by the method of obtaining food and in which all organisms are the same number of energy transfers away from the original source of the energy (photosynthesis)
Term
Tripeptide
Definition
a peptide of three amino acid residues
Term
Triglyceride
Definition
fatty acid ester of the 3-carbon alcohol, glycerol- forms into globules because of its hydrophobic properties
Term
Tricuspid valve
Definition
right atrio-ventricular valve
Term
Tricarboxylic acid (TCA) cycle
Definition
the stage in tissue respiration in which pyruvate is broken down to carbon dioxide, and hydrogen is removed for subsequent oxidation
Term
Transpiration
Definition
loss of water vapour from the aerial parts of plants (leaves and stem)
Term
Transmitter substances
Definition
substances released into the synaptic cleft on arrival of an impulse at the pre-synaptic membrane to conduct the signal across the synapse
Term
Translation
Definition
the information of mRNA is decoded into protein (amino acid sequence)
Term
Transfer RNA (tRNA)
Definition
short lengths of specific RNA that combine with specific amino acids prior to protein synthesis
Term
Transcription
Definition
when the DNA sequence is converted into mRNA
Term
Trait
Definition
a tendency or characteristic
Term
Tracheole
Definition
branch of the trachea
Term
Trachea
Definition
windpipe
Term
Tonoplast
Definition
membrane around the plant cell vacuole
Term
Tissue respiration
Definition
biochemical steps by which energy is released from sugars
Term
Tissue
Definition
collection of cells of similar structure and function
Term
Thyroid gland
Definition
an endocrine gland found in the neck of vertebrates, site of production of thyroxine and other hormones influencing the rate of metabolism
Term
Thrombosis
Definition
blood clot formation, leading to blockage of a blood vessel
Term
Threshold of simulation
Definition
the level of stimulation required to trigger an action potential (impulse)
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