Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

biology paper 2 > 14 response to stimuli > Flashcards

14 response to stimuli Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what is a stimulus?

A

a detectable change in the internal or external environment of an organism that leads to a response in the organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a taxis?

A

a simple response whose direction is determined by the direction of the stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a positive taxis?

A

movement towards stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a negative taxis?

A

movement away from stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a kinesis?

A

a non-directional response, an effective way of finding favourable conditions when they cannot detect which direction to go

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a tropism?

A

the growth of part of a plant in response to a directional stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do plants respond to changes in environment?

A

light: shoots grow towards light because needed for photosyntheses
gravity: roots grow in direction of its pull because need to be firmly anchored in soil
water: roots grow towards water for photosynthesis and other metabolic processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is IAA?

A

indoleacetic acid, a type of auxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how does phototropism occur in flowering plants?

A

1) cells in shoot tip produce IAA which is transported evenly down the shoot
2) light causes IAA to move from light to shaded side of shoot so greater conc on shaded side
3) IAA causes cells on this side to elongate more
4) shaded side elongates faster than light side, causing shoot tip to bend towards light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how does gravitropism occur in flowering plants?

A

1) cells in root tip produce IAA which is evenly transported along the root
2) gravity causes movement of IAA from upper to lower side of root so greater conc of IAA on lower side
3) IAA inhibits elongation of root cells so cells on lower side elongate less than those on the upper side
4) cells on upper side elongate faster than lower side causing root to bend downwards towards force of gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the effect of IAA in shoots and roots?

A

shoots: causes elongation of shoots
roots: inhibits elongation of shoots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the major divisions of the nervous system?

A

central nervous system: brain and spinal cord

peripheral nervous system: pairs of nerves that originate from brain or spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the peripheral nervous system divided into?

A

sensory neurones: carry nerve impulses from receptors towards CNS
motor neurones: carry nerve impulses from CNS to effectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how can the motor nervous system be divided?

A

voluntary nervous system: carries nerve impulses to body muscles, under voluntary control

autonomic nervous system: carries nerve impulses to glands, smooth muscle and cardiac muscle, involuntary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the spinal cord?

A

a column of nervous tissue that runs along back and lies inside vertebral column for protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a reflex arc?

A

the nerve pathway in the body taken by an action potential that leads to a rapid, involuntary response to a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the sequence of a reflex arc?

A

stimulus > receptor > sensory neurone > coordinator > motor neurone > effector > response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how many neurones are in a reflex arc?

A

3 : sensory neurone, coordinator (intermediate neurone), motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

why are reflex actions important?

A
  • involuntary so don’t require decision making of brain, so brain can carry out more complex situations and not overloaded with situations
  • protect the body from harm
  • fast because short neurone pathway with few synapses
  • fast because no decision-making process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are features of sensory receptors?

A

specific to a single type of stimulus
produces a generator potential by acting as a transducer (transducers convert energy from stimulus into a nerve impulse called a generator potential)

21
Q

what stimulus do pacinian corpuscles respond to?

A

changes in mechanical pressure

22
Q

structure of a pacinian corpuscle

A

single sensory neurone (nerve ending) at the centre of layers of tissue each separated by a gel

stretch-mediated sodium channels in the membrane

23
Q

how does the pacinian corpuscle work?

A

1) in resting state stretch-mediated sodium channels too narrow to allow sodium ions to pass along them
2) when pressure is applied membrane becomes deformed and stretched which widens sodium channels allowing sodium ions to diffuse into neurone
3) influx of sodium ions changes potential of membrane (depolarised), producing a generator potential
4) generator potential creates action potential that passes along neurone to CNS

24
Q

what are the main types of cells found in the retina?

A

rod cells

cone cells

25
Q

what are features of rod cells?

A

cannot distinguish different wavelengths of light so images only seen in black and white

can detect light of low intensity because many rod cells connect to one sensory neurone (retinal convergence)

cannot distinguish between separate sources of light so low visual acuity

26
Q

how to rod cells create a generator potential?

A

pigment of rod cells (rhodopsin) must be broken down by light energy, enough pigment has to be broken down to meet threshold in bipolar cell

threshold can be reached in low light because many rod cells connected to a single bipolar cell (summation)

27
Q

what are the types of cone cells?

A

3 types that contain different types of iodopsin pigment (red, green and blue)

depending on proportion of each cone cell stimulation we perceive colour images

28
Q

differences between rod and cone cells

A

rod-shaped, cone-shaped
greater number of rod cells than cone cells
more rod cells at periphery of retina, cone cells concentrated at fovea
rod cells give poor visual acuity, cone cells give good visual acuity
rod cells sensitive to low-intensity light, cone cells not
one type of rod cell, three types of cone cells

29
Q

what are features of cone cells?

A

connected to one bipolar cell so only respond to high light intensity

contain iodopsin which requires a higher light intensity for its breakdown

connected to one bipolar cell so high visual acuity

30
Q

what is the distribution of rod cells?

A

found at peripheries of the retina where light intensity is lowest

31
Q

what is the distribution of cone cells?

A

found at the fovea where light intensity is highest

32
Q

how does the distribution of rod and cone cells and connection to optic nerve explain differences in sensitivity and visual acuity in mammals?

A

by having different types of light receptor, each resounding to different stimuli, mammals can benefit from good all-round vision both day and night

32
Q

how does the distribution of rod and cone cells and connection to optic nerve explain differences in sensitivity and visual acuity in mammals?

A

by having different types of light receptor, each resounding to different stimuli, mammals can benefit from good all-round vision both day and night

33
Q

what is the role of the autonomic nervous system?

A

controls the involuntary activities of internal muscles and glands

34
Q

what are the two divisions of the autonomic nervous system?

A

sympathetic nervous system

parasympathetic nervous system

35
Q

what is the role of the sympathetic nervous system?

A

stimulates effectors so speeds up activity (fight or flight response)

36
Q

what is the role of the parasympathetic nervous system?

A

inhibits effectors so slows down activity, controls activities under resting conditions

conserves energy and replenishing the body’s reserve

37
Q

why is cardiac muscle myogenic?

A

its contraction is initiated from within the muscle itself rather that by nervous impulses from outside

38
Q

what is the sequence of events that controls the basic heart rate?

A

1) wave of excitation from sinoatrial node spreads across atria causing them to contract
2) layer of non-conductive tissue (AV septum) prevents wave going to ventricles
3) wave of excitation enter AVN, which after a short delay conveys a wave of excitation between ventricles along purkyne tissues which make up bundle of His
4) wave of excitation released from Purkyne tissue, causing ventricles to contract quickly from the apex upwards

39
Q

what are the three structures on the heart involved in propagating a heart beat?

A

sinoatrial node
atrioventricular node
purkyne fibres on the bundle of His

40
Q

what can be used to test kinesis responses in woodlice?

A

a choice chamber

41
Q

what region of the brain controls changes in heart rate?

A

medulla oblongata

42
Q

how do the two parts of the autonomic nervous system affect heart rate?

A

sympathetic increased heart rate

parasympathetic slows heart rate

43
Q

what are the two key types of receptors involved in controlling heart rate and where are they located?

A

chemoreceptors and pressure receptors (baroreceptors)

found in wall of carotid artery and aorta

44
Q

how do chemoreceptors control heart rate?

A

1) blood has high CO2 conc so low pH, chemoreceptors detect change and increase frequency of nervous impulses to medulla oblongata which increase heart rate
2) this increases frequency of impulses via sympathetic nervous system to SN which increases rate of waves it produces, increasing heart rate
3) increased blood flow means more CO2 removed by lungs so CO2 conc and in turn pH return to normal
4) chemoreceptors reduce frequency of nerve impulses which in turn reduced heart rate

45
Q

how to pressure receptors control heart rate?

A

when blood pressure is higher than normal: pressure receptors transmit more nervous impulses to medulla oblongata that decrease heart rate which send impulses via parasympathetic nervous system to SN which decreases heart rate

when blood pressure is lower than normal: pressure receptors transmit more nervous impulses to medulla oblongata that increase heart rate which send impulses via sympathetic nervous system to SN which increases hear rate

46
Q

what controls tropisms?

A

plant growth factors e.g IAA

47
Q

where are pacinian corpuscle found?

A

feet and fingers

biology paper 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions