animal and plant responses Flashcards
where is the cerebrum and what does it control
front of brain, largest part, has thing outer layer which is highly folded, involved in vision, learning and thinking
where is the hypothalamus and what does it control
above pituitary gland, automatically controls body temperature, produces hormones that control pituitary gland
where is the medulla oblongata and where is it found
at base of brain, automatically controls breathing rate and heart rate
where is the cerebellum and what does it control
underneath cerebrum, important for muscle coordination, posture and balance
where is the pituitary gland and what does it control
beneath hypothalamus, stimulates other glands by releasing hormones e.g adrenal glands
what is a reflex action
a body response to a stimulus without a conscious decision to respond
what is an example of a reflex action
knee-jerk reaction
what triggers the flight or fight response
release of ACTH
what receptors are in aorta and carotid arteries and what are they stimulated by
baroreceptors, high and low blood pressure
what happens when baroreceptors detect high and low blood pressure
high- send impulses along sensory neurones to cardiovascular centre, sending impulses along parasympathetic neurones, secrete acetylcholine which binds to receptors in SAN causes heart rate to slow down
low- impulses sent along to sympathetic neurones, noradrenaline secreted, which binds to receptors SAN, causes heart rate to speed up
what is the student t test used to investigate
if there is a significant difference between two sets of data
what is the structure and function of skeletal muscle
large bundles of muscle fibres, cell membrane of muscle fibres is called sacrolemma, this folds to form sarcoplasm, folds are called transverse tubules and help spread electrical impulse to reach all parts of muscle fibre
sarcoplasmic reticulum runs through sarcoplasm, stores calcium ions used for muscle contraction, have long cylindrical organelles called myofibrils, cause muscle contraction
describe structure and function of myofibrils
contain bundles of thick and thin myofilaments
thick made up of myosin
thin made up of actin
draw a myofibril and label it
give detail about the structure of myosin filaments
have globular heads that are hinged so that they can move back and forth
each head has a binding site for actin and ATP
give detail about the structure of actin filaments
have binding sites for myosin heads, tropomyosin and troponin are found between actin filaments, help myofilaments move past each other
how do chemoreceptors control heart rate
detect chemical changes in blood
high O2 or low CO2 or high blood ph send impulses along parasympathetic neurones, these secrete acetylcholine
low O2, high Co2 or low ph in blood, send impulses along sympathetic neurones which secrete noradrenaline
what is a neuromuscular junction
synapse between a motor neurone an a muscle cel
what neurotransmitter do neuromuscular junctions use
ACh
how do chemicals affect neurotransmission
chemical may block the release of the neurotransmitter or affect the way it binds to the receptors
what are some plat responses to herbivory
alkaloids- chemicals with bitter tastes
tannins- taste bitter, can make it hard to digest
pheromones- signalling hormones
what is phototropism
growth of a plant in response to light
what is a tropism
the response of a plant to a directional stimulus
what is geotropism
the growth of a plant in response to gravity
what do gibberellins do
stimulate seed germination, ste elongation, side shoot formation and flowering
what do auxins do
stimulate cell growth of shoots by cell elongation
where is auxin found
tip of shoots
what is apical dominance
when the apical bud is dominant over the lateral buds as auxin produced in the apical bud inhibits the growth of side shoots
how do gibberellins stimulate plant growth
by triggering the breakdown of starch into glucose in the seed
auxins and gibberellins are often….but can also be….
synergistic, antagonistic
what triggers leaf loss and what prevent it
ethene
auxin
what plant hormone stimulates stomatal closure
abscisic acid
what does ethene do
stimulates enzymes that break down cells walls, breakdown chlorophyll and converts starch into sugars (fruit ripening)
how are auxins used commercially
weedkillers- Mae plants grow long stems instead of lots of leaves
used as rooting hormones to clone plants
