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33 Cards in this Set
- Front
- Back
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What three types of neurones is the nervous system made up of? |
Sensory neurone, relay neurone and motor neurone
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What are the five steps for co-ordination?
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Stimulus
Receptor Co-ordinator Effector Response |
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What is homeostasis?
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Maintaining a constant internal environment
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Which four things does homeostasis control?
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Level of carbon dioxide
Water Body temperature Blood sugar levels |
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What is negative feedback?
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Changes in the environmental trigger a response that counteracts the change
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What monitors and controls the body temperature?
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The hypothalmus (thermoregulatory system) in the brain
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How does the thermoregulatory system control body temperature?
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Contains receptors that are sensitive to the blood temperature
Recieves impules from brain on skin temperature Uses nervous and hormanol systems to initiate temperature control mechanisms |
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What happens when the body is too hot?
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Hairs lie flat
Sweat is produced Blood vessels widen (vasodilation) |
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What happens when the body is too cold?
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Hairs stand up
Little sweat is produced Shiver Blood vessels constrict (vasoconstriction) |
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What is type 1 diabetes?
When is it diagnosed? How is it treated/controlled? |
When the pancreas can not produce insulin
Diagnosed early in life and can be genetic Control with insulin injections |
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What is type 2 diabetes?
When is it diagnosed? How is it controlled/treated? |
When the body makes insulin but cannot use it properly by the body cells
Older age from diet and obesity Control with exercise and diet |
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What happens when the prancres detects an increase in blood glucose?
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Produces insulin to convert the glucose into gylcogen and store in the liver to lower the blood sugar after a meal
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What are auxins?
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Plant hormones that cause plant cells to elongate or inhibit growth = causes to grow in a particular direction
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Where are auxins made?
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In the tips of the roots and shoots
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What is phototropism?
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The auxins diffuse to the shaded side of the shoot = elongation
The plant shoot grows towards the light |
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What is geotropism?
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The auxins diffuse to the underside of the rood = inhibit growth
The plant roots frow towards gravity |
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What four commerical uses do plant hormones have?
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Rooting powder = make plant cuttings grow roots
Dormancy control = make seeds germinate Slow/speed up ripening = doesn't spoil in transport but ready to sell Selective weed killer = plants grow too fast and die |
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What does the nucleus of a cell contain?
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Genetic material in the form of chromosomes
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What do chromosomes carry?
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Genes
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What do genes do?
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Control characteristics
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What two things are characteristics controlled by?
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Genetics : because of the different genes an organism has inherited
Environmental factors: the different conditions it has developed in |
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What three things is variation caused by?
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1. Genes being "shuffled" in gametes
2. Gametes fuse randomly 3. Mutations in chromosomes |
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How does a mutated gene cause a change in characteristics?
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The gene produces a different sequence of amino acids so a different protein is made overall
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What three things cause mutations?
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Exposure to:
Radiation and UV light Radioactive substances Certain chemicals |
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What is an allele?
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A different form of the same gene
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What is a dominant allele?
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Controls the characteristic when its on one of the chromosomes in a pair no matter what the other one is
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What is a recessive allele?
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Allele that controls the characteristic if a dominant allele is not present
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What does homozygous mean?
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When both chromosomes in a pair have the same allele of a gene
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What does heterozygous mean?
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When both chromosomes in a pair have different alleles of a gene
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What is the genotype?
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Describes the allele each cell has for a certain feature
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What is the phenotype?
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The physical appearance/feature from the genotype
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What are three inherited disorders that are caused by recessive alleles?
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Colour blind
Cystic fibrosis Huntington's disease |
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What does gender depend on?
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Whether the egg is fertilised by an X or Y carrying sperm
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