5.1.5-animal and plant responses Flashcards
what is the nervous system
5.1.5(g)
network of all the neurons in the body
what does the CNS consist of
5.1.5(g)
relay, sensory and motor neurons
what does the PNS consist of
5.1.5(g)
sensory and motor neurons
what is the role of the autonomic nervous system
5.1.5(g)
conducts action potential from the CNS to effector
-involuntary
what is the role of the somatic nervous system
5.1.5(g)
sensory receptor to CNS to muscle
-voluntary
what is the role of the sympathetic nervous system
5.1.5(g)
make involuntary bodily processes more active by increase fight or flight
-increase heart rate/breathing rate, dilates pupils, reduces digestive activity
what is the role of the parasympathetic nervous system
5.1.5(g)
make involuntary bodily processes less active to restore normal physiological functioning
-decreases heart rate/ breathing rate, constricts pupils and increases digestive activity
what is the cerebrum
5.1.5(h)
-has 2 hemispheres connected by the corpus callosum
-controls voluntary movement
-controls conscious thought and actions
what is the cerebellum
5.1.5(h)
controls involuntary movement and balance
-it does this through receiving information from sensory receptors
what is the hypothalamus
5.1.5(h)
controls homeostatic mechanisms
eg-thermoregulation and osmosregulation
-it either releases hormones or stimulates the pituitary gland to release hormones
what is the role of the posterior pituitary gland
5.1.5(h)
stores and release hormones from the hypothalamus eg-ADH
what is the role of the anterior pituitary gland
5.1.5(h)
produces and release hormones in response to releasing factors produced by the hypothalamus eg-FSH
what is the role of the medulla oblongata
5.1.5(h)
regulates function of ANS
eg-breathing and heart rate
label the structures of the brain
5.1.5(h)
in booklet
what is a reflex action
5.1.5(i)
an involuntary response in response to a stimulus.
what are some positives of reflex action
5.1.5(i)
-its fast
-minimises/prevent damage
what type of reflex is the knee-jerk reflex
5.1.5(i)
spinal reflex as it passes through the spinal column
describe the knee-jerk reflex
5.1.5(i)
- Patellar tendon stretches
- stretch receptors detect this
- Sends an impulse to a sensory neuron
- In the spinal cord the sensory neuron transmits this information to a motor neuron
- The motor neuron carries this information back to an effector
- this causes the leg muscles to contract and therefore kick
are there any relay neurons in the knee-jerk reflex
5.1.5(i)
no
this makes it faster as there only one synapse involved
what type of reflex is the blinking reflex
5.1.5(i)
cranial reflex
describe the blinking reflex
5.1.5(i)
- object hits the cornea
- sensory neurons in cornea detect this
- they send an action potential to a sensory to a relay neuron to a motor neuron to the effector which eyelid muscles which then close
what is the difference between a cranial and spinal reflex
5.1.5(i)
cranial reflex- if the relay neuron is found in the brain
spinal reflex-if the relay neuron is found in the spina cord
describe the fight or flight response
5.1.5(j)
- receptors detect a threat
- sensory neurons sends AP to the hypothalamus
- hypothalamus increases activity in sympathetic nervous system and stimulates release or hormones from anterior pituitary gland
- the adrenal medulla is activated causing adrenaline secretion
describe how adrenaline works
5.1.5(j)
- adrenaline is a peptide hormone
- it binds to G-coupled proteins on CSM of target cells
- G-protein activates adenyl cyclase inside cells
- Adenyl cyclase converts ATP into cAMP
- cAMP activates other enzymes that cause cells response to adrenaline
describe the release of hormones from the anterior pituitary gland
5.1.5(j)
hypothalamus secretes releasing factors
the anterior pituitary gland detects this and release tropic hormones into the blood and target cells which are found in endocrine glands
what are the 2 releasing hormones called
5.1.5(j)
corticotropin releasing hormone
thyrotropin releasing hormone
describe the action of corticotropin releasing hormone
5.1.5(j)
- hypothalamus secretes corticotropin releasing hormone
- this causes the release of ACTH
- ACTH binds to receptors on the adrenal cortex
- This causes them to release corticosteriods such as cortisol. Cortiscosteriods also cause gluconeogensis and glycogenolysis
describe the action of thryotropin releasing hormone
5.1.5(j)
- hypothalamus secretes thyrotropin releasing hormone
- This causes release of thyroxine from thyroid gland
- thyroxine binds to target cells and causes metabolic rate to increase.
what are chemoreceptors and where are they located
5.1.5(k)
monitor the pH of the blood
located in the carotid arteries and aorta
what are baroreceptors and where are they located
5.1.5(k)
monitor blood pressure
located in the carotid arteries
what happens if blood pressure or pH is too low
5.1.5(k)
- baro/chemo receptors detect BP or pH change
- sends impulses along the medulla oblongata
- if BP or pH is too low then cardio stimulatory centre is triggered to send impulse via accelerator nerve to SAN to increase HR
- if BP or pH is too high then cardioinhibitory centre is triggered to send an impulse via vagus nerve to SAN to decrease HR
describe the hormonal control of heart rate
5.1.5(k)
cardiac muscles have receptors for adrenaline on there CSM so they can respond to adrenaline directly. Adrenaline causes a increase in the rate of cardiac muscle contraction so heart rate increases.
describe the unpaired t-test
5.1.5(k)
in booklet
what is skeletal muscle
5.1.5(l)
function-to move limbs and contains antagonistic pairs where one contracts and the other relaxes.
structure-multinucleated, tube-shaped and striated
what is cardiac muscle
5.1.5(l)
function-to pump blood
structure-striated, uninucleated and branched
what is involuntary muscle
5.1.5(l)
function-to move blood around organs
structure-uninucleated, non-striated and spindle shaped
describe the microscopic muscle structure
5.1.5(l)
skeletal muscle, bundle of muscle fibre, muscle fibre and myofibril
describe a sacromere
5.1.5(l)
booklet
describe a thick filament
5.1.5(l)
myosin chain
head
tail
describe a thin filament
5.1.5(l)
actin chain
wrapped around tropomyosin
what is a neuromuscular junction
5.1.5(l)
junction between a motor neuron and a muscle
describe how you would stimulate contraction
5.1.5(l)
- Action potentials arrive at the end of the motor neuron. Ca2+ VGICs open. Ca2+ enter the motor neuron by diffusihat won.
- Vesicles of acetylcholine move and fuse with the motor neuron membrane.
- Acetylcholine molecules diffuse across the gap and bind to Na+ LGICs on the sarcolemma.
- Na+ LGICs open and Na+ diffuse into the muscle fibre, causing the sarcolemma to depolarise.
- A wave of depolarisation spreads along the sarcolemma and down transverse tubules towards the centre of the muscle fibre.
- This causes the sarcoplasmic reticulum to release stored Ca2+, which leads to muscle contraction.
what are the 3 main parts of the sliding muscle contraction
5.1.5(l)
- stimulation
- attachment
3.detachment
what are some of the chemical defences produced by plants and what do they do
5.1.5(a)
Tannins and alkaloids-bitter compounds that are toxic
phermones-cause nearby plants to increase callose production making it harder to herbivory to eat
what are the 2 types of physical defences
5.1.5(a)
-thorns and spikes-
-folding in touch response-mimosa Pudica folds it leaves inwards when touched helping to knock off insect herbivores
what is phototropism
5.1.5(a)
where shoots grow towards light (positive phototropism)
and roots grow away from light (negative phototropism)
how does phototropism occur
5.1.5(a)
-auxin is produced in the shoot tip
-its transported towards the shaded side
-auxin causes cells on the shaded side to enlongate
-the shaded side grows faster than the side in the light.
what did scientists orginally think about auxin
5.1.5(a)
they thought bright light causes auxin to be destroyed rather than causing it to be moved to the shaded side.
why have scientific ideas changed over time
5.1.5(a)
what happens if a plant is in the dark
5.1.5(a)
it tries to grow quickly and upwards to find a light source for photosynthesis
plants grown in the dark become tall and produce little to no chlorophyll-this is called etiolation
which hormone is responsible for etiolation
5.1.5(a)
gibberlin
what is geo/gravitropsim
5.1.5(a)
where plant roots grow downwards due to gravity
explain how geotropism works
5.1.5(a)
-cells in roots contain amyloplasts
-amyloplasts sink in the direction of gravity
-binding of amyloplasts with ER releases Ca2+
-ca2+ stimulates growth
-root grows towards side with amyloplasts/ca2+ release
-in roots auxin inhibits root cell growth
what processes do plant hormones carry out in response to abiotic stress
5.1.5(b)
-leaf abscission
-seed germination
-stomatal closure
describe the process of leaf abscission
5.1.5(b)
-plant cells detect day length using light-sensitive chemical called phytochrome
-when they detect a lack of light this causes auxin production to drop and ethene levels too increase
-in response to ethene cells in the abscission zone transcribe and translate hydrolytic enzymes which hydrolyse cellulose cell wall
-the leaf drops off
what happens before lead abscission
5.1.5(b)
the leaves turn yellow
useful product eg-chlorphyl are hydrolysed and moved into the xylem or phloem
describe the process of seed germination
5.1.5(b)
-seed cells absorb H2O by osmosis
-in response the plant makes gibberellin
-gibberellin acts as a transcription factor
-increases the transcription of amylase and maltase genes
-amylase and maltase hydrolyse stored starch into glucose
-glucose is used by seed cells for respiration
describe the process of stomatal closure
5.1.5(b)
- lack of water is detected
- plants release hormone ABA (abscisic acid)
- ABA bind to receptors on the CSM of guard cells
- This causes Ca2+ channels to open so Ca2+ moves in
5.this causes K+ channels to open so K+ moves out followed by h2o by osmosis - guard cells becomes flaccid and stomata closes
where is auxin made
5.1.5(c)
tip of apical shoot
what does auxin do to the apical shoot
5.1.5(c)
-auxine binds to receptors on top of apical shoot
-promotes growth of apical shoot
-cell wall becomes acidified
-cellulose cell wall become stretchy and flexible
-turgor pressure inside cells pushes outwards on flexible cell walls and cells elongate
-auxins are destroyed and cell wall become rigid again
what does auxin do in apical shoot
5.1.5(c)
-prevents lateral buds from growing
-lateral buds near the tip of the shoot are exposed to high concentrations of auxin so they are not able to grow
-further from the tip there’s lower concentration of auxin to the lateral buds are not able to grow
what experiments have been done to show the role of auxin in lateral bud inhibition
5.1.5(c)
-if the tip of the apical shoot is removed then lateral buds can grow-this suggests an inhibitor is produced in the tips
-if auxin is applied to the decapitated tip lateral buds cannot grow
what is gibberellins responsible for
5.1.5(d)
-stem elongation
-seed germination
what was the experimental evidence for gibberelin
stem elongation
5.1.5(d)
- dwarf variety doesnt produce any gibberelin-due to mutation-internode length=0
- wild type produces the normal levels of gibberelin
- Plant with high levels of gibberelin-internode length is elongated
They also used pea plant
1. tall pea plants=higher conc of gibberelin
2.
what was the experimental evidence for gibberelin
stem elongation for exogenous gibberelin
5.1.5(d)
scientists applied a range of gibberelin to different plants and they grew taller
even when they applied it to dwarf plants they grew taller
what was the experimental evidence for gibberelin
seed germination for exogenous gibberelin
5.1.5(d)
plants can be genetically engineered to have non-functioning alleles for gibberelin synthesis. These seeds dont germinate
when exogenous gibberlin is applied seeds can germinate
AND
if inhbitors for gibberelin synthesis is applied to seeds they do not germinate. However if inhibitor is removed they can germinate
experimental evidence:starch digestion assay
5.1.5(d)
- cut embryo portion to seed is unable to make its own gibberelin
- soak seeds in range of gibberelin concentrations
- place seeds on starch agar plates and incubate
- flood agar plate with iodine solution. areas where starch has been digested will not stain blue-black
when measuring the effects of hormones on plant growth what must you do
5.1.5(e)
-prepare a suitable range of different concentrations of the hormone using a serial dilution
how can you accurately meaure 1cm cubed of a liquid
5.1.5(e)
using a volumetric pipette
how can we improve validity for this experiment
5.1.5(e)
-instead of putting the seeds in gibberelin soak them in distilled water
what factors do we need to control
5.1.5(e)
-how the growth is determined
-light intensity
-selection of plant/seeds should be random
what are 4 roles of auxin
5.1.5(f)
-fruit drop
-taking cuttings
-seedless fruit
-herbicides
how does auxin cause fruit drop
5.1.5(f)
-low conc=prevent fruit drop
-high conc-promote fruit drop
how can you take cuttings using auxin
5.1.5(f)
dip the cut end of the plant into the rooting powder. This encourages cells in the cut end to differentiate into roots
how can auxin produce seedless fruit
5.1.5(f)
-treating unpolinated plants can trigger the production of seedless fruit
how can auxin be used as a herbicide
5.1.5(f)
it promotes shoot growth so much that the weed cannot support itself
what are the 2 roles of cytokines
5.1.5(f)
leaf senescence
tissue culture
cytokines for leaf sensecence
5.1.5(f)
delay leaf senescene to prevent yellowing of salad leafs
cytokines for tissue culture
5.1.5(f)
promote bud and shoot growth so plants can be cloned on a large scale
what is the role of gibberelins
5.1.5(f)
-senescene in fruit
-seed germination
what is senescence
5.1.5(f)
delay fruit ageing
what is seed germination
5.1.5(f)
trigger seed germination so a large number of seeds can all germinate at once
so they can be stored
what are the 2 roles of ethene
5.1.5(f)
-fruit drop
-fruit ripening
ethene for fruit drop
5.1.5(f)
ethene promotes fruit drop
ethene for fruit ripening
5.1.5(f)
ethene speeds up fruit ripening
