hormonal communication💉🩸 Flashcards
where in the adrenal glands are steroids secreted
cortex
describe sequence of events that leads to insulin being secreted
- glucose diffuses into beta cell and is respired to produce ATP
- ATP closes potassium ion channels causing K+ ions to build up
- this build up causes Ca2+ channels to open so Ca2+ ions enter
- Ca2+ ions cause exocytosis of insulin vesicles
insulin secretion continues even if no further increase in blood glucose, suggest why
- glucose concentration in blood may still be high
- ATP present so K+ channels still closed
- exocytosis still triggered by Ca2+ ions
similarities between animal and plant hormones in cell signalling
- hormones bind to complementary receptor
- hormones cause cascade of events
why are plants more able to produce natural reproductive clones than animals
- most plant cells are totipotent
- plants have meristem
- most animal cells are differentiated
polyploidy is the possession of more than two sets of chromosomes in the nucleus. what is the significance of polyploidy when forming a new species of plant
- hybrids cannot reproduce sexually
- polyploidy allows hybrid to form gametes
- stronger plants
describe mechanism that causes plant to grow towards light
- apical cells produce auxin
- diffusion down shoot
- greater auxin concentration on shaded part of stem
- auxin causes cell elongation
- auxing causes cell wall loosening
describe mechanism that causes someone to cover their eyes with hand in response to a bright light
- retina detects light
- action potentials along sensory neurone
- impulse goes through motor neurone
- contraction of muscle fibres
describe how glucagon is involved in the regulation of blood glucose concentration
- glucagon released by alpha cells in pancreas
- glucagon promotes glycogenolysis (coversion of glycogen to glucose) in liver cells
- gluconeogenesis (glucose formed out of other substances ie triglycerides)
- negative feedback reduces secretion of glucagon
- glucagon reduces insulin secretion
name of endocrine tissue in pancreas responsible for secretion of hormones
islets of langerhans
explain difference between function of rna polymerase and dna polymerase
rna polymerase
- makes mRNA
- transcription
dna polymerase
- dna replication
- semi conservative
- before nuclear division
name of programmed cell death
apoptosis
describe how 2 organs may function differently in a calm mammal vs a frightened mammal (fight or flight)
lungs
- calm has slow breathing
- frightened has fast breathing
liver
- calm converts glucose to glycogen
- frightened converts glycogen to glucose
heart
- calm has small force
- frightened has great force
which division of the autonomic nervous system is active in a calm mammal and what neurotransmitter is secreted by neurones into organs
- parasympathetic
- acetylcholine
which division of the autonomic nervous system is active in a frightened mammal and what neurotransmitter is secreted by neurones into organs
- sympathetic
- noradrenaline
where is adrenaline produced
- adrenal gland
- adrenal medulla
describe the events that occur after adrenaline reaches the cell surface membrane that then result in changes in metabolism inside the cell cytoplasm
- adrenaline binds to receptor
- complementary shape
- G protein activated
- adenyl cyclase activated
- ATP converted to cAMP
- cAMP activates enzymes by phosphorylation
suggest how having a number of steps in the signalling pathway enables a small number of adrenaline molecules to rapidly cause large effects
- one adrenaline causes production of many cAMP
- multiplying effect is repeated at every step
- recycling of cAMP
one difference between secretion and excretion
- excretion produces metabolic waste
- secretion produces useful product
one similarity between excretion and secretion
- requires ATP
- involved in homeostasis
how is type 1 diabetes caused
- body cannot produce insulin
- beta cells damaged
risk factors for type 2 diabetes
- obesity
- lack of physical activity
- excessive alcohol intake
- high blood pressure
describe how the pancreas acts as an endocrine and exocrine gland
endocrine
- hormones secreted into blood
- alpha cells produce glucagon
- beta cells produce insulin
exocrine
- digestive enzymes such as amylase, protease, lipase
- secreted into duct
- secretions go to small intenstine
advantages of treating type 1 diabetes with insulin from gmo bacteria over insulin from pigs
- cheaper
- more dependable supply, more abundant
- more ethical
- human insulin produced rather than pigs
cAMP in the liver activates enzymes. suggest what happens to polysaccharides in a liver cell
glycogenolysis
outline the hormonal and nervous mechanisms involved in the control of heart rate
- adrenaline increases heart rate
- cardiovascular centre in medulla oblongata
- nervous connection to SAN which controls frequency of waves of excitation
- parasympathetic nerve decreases heart rate
- sympathetic nerve increases heart rate
- high blood pressure detected by stretch receptors
- low blood pH detected by chemoreceptors
difference in starch and sucrose effect on blood glucose concentration
- starch only contains glucose
- sucrose contains glucose and fructose
- by hydrolysis starch releases more glucose
difference in starch and cellulose effect on blood glucose concentration
- starch is digestible
- cellulose is indigestible
- amylase for starch digestion
- no cellulase for cellulose digestion
what are glucocorticoids
- cortisol helps regulate metabolism by controlling how fats proteins carbs are converted to energy, helps regulate blood pressure in response to stress
- corticosterone works with cortisol to regulate immune response
- release controlled by hypothalamus
