Brainscape's Knowledge GenomeTM

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


See full index

biology > survival and response > Flashcards

survival and response Flashcards

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

why do plants react to changes?

A

plants respond to changes in their environment to increase their chances of survival

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

what are plant growth factors and where are they produced?

A
  • chemicals that regulate plant growth response to directional stimuli
  • produced in plant growing regions (apical meristems)
  • diffuse from cell to cell / phloem mass transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

define tropism

A

the growth response of a plant to a directional stimulus

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

define phototropism

A

plant growth response to a light source

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

define gravitropism

A

plant growth response to gravity that directs roots downward

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

explain why shoots show positive phototropism

A
  • indoleacetic acid (IAA) diffuses to shaded side of shoot tip
  • as IAA diffuses down shaded side, it causes active transport of H+ ions into the cell wall
  • disruption of H-bonds between cellulose molecules and action of expansins makes cell more permeable to water
  • cells on shaded side elongate faster due to higher turgor pressure
  • shoot bends towards the light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain why roots show positive gravitropism

A
  • gravity causes IAA to accumulate on lower side of the root
  • IAA inhibits elongation of root cells
  • cells on the upper side of the root elongate faster so the root tip bends downwards
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

contrast mammalian hormones and plant growth factors (CASTS)

A
  1. concentration
    - in mammals response is not always dependent on concentration
    - in plants response is proportional to the concentration
  2. action
    - in mammals growth factors bind to complementary proteins in/on target cells
    - in plants growth factors can affect all cells
  3. synthesis
    - mammals have specialised glands
    - plants have various tissues in growing regions
  4. transport
    - mammals have the circulatory system
    - plants have diffusion or translocation
  5. speed
    - mammals are faster acting due to homeostasis
    - plants are slower acting due to plant growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define taxis and kinesis, state their advantage

A
  • taxis: directional movement in response to an external stimulus
  • kinesis: non-directional response to presence and intensity of external stimulus
  • maintains a mobile organism in optimum environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

many organisms respond to temperature and humidity via kinesis rather than taxis, why?

A
  • less directional stimuli
  • often no clear gradient from one extreme to the other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how could a student recognise kinesis in an organism’s movement

A
  1. organism crosses a sharp division between favourable and unfavourable environment: turning increases (the return to the original favourable environment)
  2. if an organism moves considerable distance into unfavourable environment: turning slowly decreases and begins to move in long straight lines, sharper turns (leads organism into new environment)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

outline what happens in a simple reflex arc

A
  1. receptor detects stimulus
  2. passes stimulus to sensory neurone
  3. sensory neurone sends electrical impulses to the relay neurone in CNS coordinates response
  4. relay neurone connects to the motor neurone and passes the impulses on
  5. motor neurone carries impulse to the effector
  6. effector triggers response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

give the advantages of a simple reflex

A
  1. rapid response to potentially dangerous stimuli since only 3 neurones are involved
  2. Instinctive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

suggest a suitable statistical test to determine whether a factor has a significant effect on the movement of an animal in a choice chamber

A

chi squared

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

what features are common to all sensory receptors?

A
  • act as energy transducers which establish a generator potential
  • respond to specific stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the basic structure of a pacinian corpuscle

A
  • single nerve fibre surrounded by layers of connective tissue which are separated by viscous gel and contained by a capsule
  • stretch mediated Na+ channels on plasma membrane
  • capillary runs along base layer of tissue
17
Q

what stimulus does a Pacinian corpuscle respond to? how?

A
  1. pressure deforms the membrane causing stretch-mediated Na+ ion channels to open
  2. an influx of Na+ raises membrane to threshold potential, a generator potential is produced
  3. action potential moves along sensory neuron
18
Q

name the 2 types of photoreceptor cell located in the retina

A
  1. cone cells
  2. rod cells
19
Q

where are rod and cone cells located in the retina?

A

rod - evenly distributed around periphery not in central fovea

cone - mainly central fovea no photoreceptors at blind spot

20
Q

compare and contrast rod and cone cells (PACL)

A
  1. pigment in rod cells is rhodopsin, in cone cells its 3 types of iodopsin
  2. visual acuity: rod cells have low resolution, many rod cells synapse with 1 neuron, cone cells have high resolution because 1 cone cell synapses with 1 neurone so no retinal convergence
  3. colour sensitivity: rod cells are monochromatic so all wavelengths of light detected, cone cells are tricolour so only red blue and green wavelengths are absorbed
  4. light sensitivity: rod cells are very sensitive due to spatial summation of subthreshold impulses, cone cells are less sensitive and they are not involved in night vision
21
Q

outline the pathway of light from a photoreceptor in the brain

A

photoreceptor -> neurone -> ganglion cell of optic nerve -> brain

22
Q

define myogenic

A

contraction of the heart is initiated within the muscle itself rather than by nerve impulses

23
Q

state and name the location of the 2 nodes involved in heart contraction

A
  1. sinoatrial note (SAN): within the wall of the right atrium
  2. atrioventricular node (AVN): near the lower end of the right atrium in the wall that separates the 2 atria
24
Q

describe how heartbeats are initiated and coordinated

A
  1. sinoatrial node initiates a wave of depolarisation
  2. wave of depolarisation spreads across both atria causing atrial systole
  3. layer of fibrous, non-conducting tissue delays impulse while ventricles fill and valves close
  4. atrioventricular node conveys a wave of depolarisation down the septum via the Bundle of His, which branches into Purkinje fibres along ventricles
  5. causes ventricles to contract from the apex upwards
25
Q

state the formula for cardiac output

A

cardiac output = stroke volume x heart rate

26
Q

what is the autonomic nervous system?

A
  • a system that controls involuntary actions of glands and muscles
  • 2 subdivisions: sympathetic and parasympathetic
27
Q

state the difference between the sympathetic and parasympathetic nervous system

A
  • sympathetic involved in flight or fight responses that stimulate effectors to speed up activity
  • parasympathetic involved in normal resting conditions, inhibits effectors to slow down activity
28
Q

name the receptors involved in changing heart rate and state their location

A
  • baroreceptors: detect changes in blood pressure, in the carotid body
  • chemoreceptors: detect changes in pH, carotid body and aortic body
29
Q

how does the body respond to a decrease in blood pressure?

A
  1. baroreceptors detect low blood pressure
  2. Impulses are sent to the medulla oblongata
  3. which sends impulses along sympathetic neurones
  4. these secrete noradrenaline which binds to receptors on the sinoatrial node
  5. noradrenaline increases heart rate
  6. heart rate increases to increase blood pressure back to normal
30
Q

how does the body respond to an increase in blood pressure?

A
  1. baroreceptors detect increase in blood pressure
  2. impulses are sent to the medulla
  3. which sends impulses along parasympathetic neurones
  4. these secrete acetylcholine, which binds to receptors on the sinoatrial node
  5. acetylcholine decreases heart rate which returns blood pressure back to normal
31
Q

how does the body respond to a decrease in CO2 concentration and high ph levels?

A
  1. chemoreceptors detect an decrease in CO2 concentration and high pH levels
  2. Impulses are sent to the medulla which sends impulses along parasympathetic neurones
  3. These secrete acetylcholine, which binds to receptors on the sinoatrial node
  4. heart rate decreases to return carbon dioxide and pH back to normal
32
Q

how does the body respond to an increase in CO2 and a decrease in pH

A
  1. chemoreceptors detect chemical changes in the blood
  2. impulses are sent to the medulla which sends impulses along sympathetic neurones
  3. these secrete noradrenaline which binds to receptors on the sinoatrial node
  4. heart rate increases to return CO2 and pH levels back to normal

biology (46 decks)

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