Flashcards in Biology Paper 2 Deck (67):
What is homeostasis?
The regulation of internal conditions of a cell or organism in response to internal or external changes
What does homeostasis control?
Blood glucose concentration
Water an ion levels
What is the order of the negative feedback system of control system?
What controls body temperature?
The thermoregulatory centre
If temperature is too high?
If temperature too low?
What does the cerebral cortex control?
Consciousness, intelligence, memory and language
What does the cerebellum control?
What does the medulla control?
What does the retina do?
Contains reception cells that are sensitive to light
Carries impulses from retina to the brain
Tough outer layer with transparent region called cornea
Controls size of pupils and amount of light reaching retina
Ciliary muscled and suspensory ligaments
Change shape of lens to focus light
What is Accommodation?
Process of changing shape of lens to focus on objects
What is myopia?
Which system is faster?
The effects of the hormones are slower and act for longer
What does Thyroxine do?
Increase metabolic rate
Controls growth and development in young
Controlled by negative feedback
What happens in blood glucose is too low?
Glucagon stimulates glycogen to convert back to glucose
What controls the balance of water?
What is urea?
Produced by liver from breakdown of proteins and contains nitrogen
What are excess amino acids converted to?
Ammonia in process called deamination
Urine produced by
Urea and excess water and ions
Where does production of urine take place?
What is ADH?
Released by pituitary gland when blood con. too high
Cause more water to be reabsorbed
What does a dialysis machine do?
Takes over role of kidneys
What is FSH?
Produced by pituitary gland
Causes eggs to mature
Stimulates ovaries to produce oestrogen
What is Oestrogen?
Produced by ovaries
Makes lining grow
What is LH?
Produced by pituitary gland
Stimulates release of egg
What is Progesterone?
Produced by empty follicle in ovaries
Inhibits FSH and LH
What does the combines pill contain?
Oestrogen and progesterone
What does a implant contain?
What is IVF?
Gives a woman LH and FSH to grow many eggs
Fertilise eggs with sperm
Insert embryos into womb
What is a tropism?
Response involving growth in a direction
Gravitropism in shoots
Gravitropism in toots
Phototropism I’m shoots
Phototropism in roots
What are gibberellins?
Plant hormone important in germination
What is ethane?
Gas and hormone controls cell division and ripening of fruits
Auxins are used as
Weed killers, grow too fast
Promoting tissue culture
Gibberellins are used for
End seed dormancy
Increase fruit size
Advantages of sexual reproduction
If environment changes, survive
Advantages of asexual reproduction
More time and energy efficient
What is a genome
Organisms entire genetic material
What is DNA
Polymer made up of nucleotides
What does a nucleotide contain?
One of 4 base; A, C, G or T
What bases attract
C links with a G
T links with an A
How is a protein made?
Carrier molecules bring amino acids in correct order
Chain down, folds
Unique shape to do jobs
Who was Gregor Mendel?
Originally, blend of characteristics
Breeding on pea plants
Units called genes
Not recognised though
What is an allele?
Different forms of genes
What is a genotype?
Combination of alleles present in a gene
What is a phenotype?
How the alleles are expressed
What is homozygous
What is heterozygous
What is monohybrid inheritance
Only one gene involved
What is polydactyl
Extra fingers or toes caused by dominant alleles
What is cystic fibrosis
Disorder of cell membranes cause by recessive alleles
How are fossils formed?
Hard parts of animals that do not decay easily
Parts of organisms that have not decayed
Parts of organisms replaced by other materials
Preserved traces of organisms
What is selective breeding?
Choose parents by characteristics
Offspring choose desired and breed
Continue and repeat
What is genetic engineering?
Enzymes used to isolate gene
Gene inserted into vector
Vector used to insert gene into cells
Remove nucleus from unfertilised egg cell
Insert nucleus into adult body cell
Stimulate egg to divide
Allow embryo to develop
Insert embryo into surrogate
Principles of classification
What is the binomial system
Three domain system is divided into