A2 OCR Biology- F215-Control, Genomes and the Environment: glossary.

A2 OCR Biology.

F215: Control, Genomes and the Environment

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GLOSSARY FOR UNIT 4
Key word Definition
Abiotic factors Non-living factors.
Ecosystem
Abiotic stress pH levels, light intensity and minerals.
Plant responses
Abscission Where the leaf drops.
Plant responses
Allele It is an alternative version of a gene. It is still at the same
Meiosis and variation locus on the chromosome and codes for the same
polypeptide but the alteration to the DNA base sequence
may alter the protein's structure.
Allopatric speciation This is a result of geographical isolation, e.g. a barrier such as
Variation a desert or a mountain.
Anaphase I 1. Spindle contracts, one chromosome pulls to the
Meiosis and variation pole.
Anaphase II 1. Spindle contracts and chromatids at pole.
Meiosis and variation
Apical dominance Apex dominates whether there are any side brances.
Plant responses
Apoptosis This is programmed (intentional) cell death.
Cellular control
Artificial selection This is where the selection pressures are humans and they
Variation choose the most useful characteristics in order to breed.
Asepsis This is the practice of preventing contamination of cultures
Biotechnology and gene technologies. by unwanted microorganisms.
Aseptic techniques Any technique used to prevent contamination.
Biotechnology and gene technologies. E.g. the use of a fume cupboard to prevent airborne
microorganisms contaminating the sample.
Autonomic nervous system This is a section of the functional/physiological nervous
Animal responses system. It is part of the involuntary nervous system. It
includes the sympathetic (fight or flight) and the
parasympathetic (rest or digest).
Autosomal linkage This is when alleles are on the same chromosome and so
gametes are reduced.
Batch culture Microorganisms are grown in individual batches in a
Biotechnology and gene technologies. fermentation vessel.
Biological species concept This is two organisms with a similar morphology and
Variation physiology that can breed to produce fertile offspring. It
doesn't take into account asexual reproducing organisms.
Biotechnology This is the industrial use of living organisms to produce food,
Biotechnology and gene technologies. drugs and other products.
Biotic factors Living factors.
Ecosystem
Body plans This is the general structure of an organism.
Cellular control
Bread wheat (Triticum aestivum) They undergo a range of steps through artificial selection:
Variation · Most wild species of wheat are diploid with 14
chromosomes: n=7. Grasses like many other
domesticated plants are able to undergo polyploidy.
Modern bread wheat is hexaploid, 6n with 42
chromosomes in their cell.
· The cells are bigger because the nuclei needs to be
larges to contain the extra chromosomes.
· Domesticated wheat is a hybrid containing three
genomes: AUAU,BB and DD. AU,AU
· AU,AU has come from a wild wheat species.

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The genome BB has come from wild emmer wheat.
Carnivores Animals that eat other animals.
Ecosystem
Carrying capacity Maximum population size that can be maintained over a
Biotechnology and gene technologies. time.
Population and sustainability
Central nervous system This includes the brain and spinal cord as part of the central
Animal responses nervous system. This is part of the anatomical nervous
system.
Cerebellum Controls balance, posture, coordination of muscle
Animal responses movement and control of muscle contraction.
Cerebrum Three areas: sensory, motor and associative area.…read more

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Cellular control
Decomposers Living organisms that feed on waste materials or dead
Ecosystem organisms.
Detritus Organic matter in dead organisms and waste mateirals.
Ecosystem
Degenerate code There is more codes than they are amino acids.
Cellular control
Dihybrid Two genes are "passed" on at a time.
Meiosis and variation
Diploid A nucleus with all its chromosomes in pairs, an example is
Meiosis and variation humans with 23 pairs.…read more

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Ecosystem
Habituation Something that causes an escape reflex if repeated again
Animal behaviour then the escape reflex stops.
Haploid A nucleus with all its chromosomes unpaired, an example in
Meiosis and variation humans would be 23 chromosomes.
Hardy-Weinberg principle Calculates the allele frequencies in population.
Meiosis and variation
Herbivores Animals that eat plants.
Ecosystem
Heterozygous Different alleles.
Meiosis and variation
Homeotic/homeobox genes They are genes that control the body plan.
Cellular control
Homozygous Same alleles.…read more

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Modern dairy cow They undergo a range of steps through artificial selection:
Variation · Each cow's milk yield is measured and recorded.
· The descendants of the bulls are tested to find out
which bulls have produced daughters with high milk
yields.
· Only a few good-quality bulls are needed to be kept
as the semen from one bull can be collected and
used to artificially inseminate many cows.
· Some 'elite' cows are given hormones so they
produce many eggs.…read more

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When the chromosomes condense, they pair up
(synapsis).
5. Crossing over occurs.
Prophase II 1. Centrioles have replicated.
Meiosis and variation
Recessive Both alleles are needed to express the feature.
Meiosis and variation
Regulators This is the structural gene (operon) for the operator.
Cellular control
Reproductive mechanism This occurs as a result of different courtship behaviour,
Variation gamete incompatibility, zygote inviability and hybrid sterility.…read more

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Telophase II 1. Chromosomes unwind and nuclear membrane
Meiosis and variation reforms.
Temporal mechanism This is where organisms live in the same area but are not
Variation active at the same time, e.g. hibernation.
Transcription This is copying part of the genetic code onto a length of RNA.
Cellular control This is also known as where mRNA is created.
Translation This is where the amino acid is assembled.
Cellular control
Trophic levels Level at which organisms feed in a food chain.…read more

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