Brainscape's Knowledge GenomeTM

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


See full index

Biology is for cool people > 14. Response to stimuli > Flashcards

14. Response to stimuli Flashcards

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

Stimulus

A

Detectable change in internal or external environment of an organism, leading to response.

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

Tropism

A

Move entire body in response to stimulus,
Positive = towards
Negative = away

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

Describe a named growth factors role in Tropism

A

IAA is a type of auxin that stimulate cell elongation in shoots and inhibit cell growth in roots.

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

Describe phototropism in shoots(4)

A

Light is needed for LDR, plant must grow towards light.

  • Shoot tip produces IAA,
  • IAA diffuses to other cells,
  • IAA diffuses to shaded side of shoot, causing uneven cell elongation.
  • This leads to plant bending towards light source.

positive phototropism

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

Describe phototropism in roots (4)

A

Roots do not require light.

IAA inhibits cell elongation, root cells elongate more on lighter side.

root bends away from light.

Negative phototropism

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

Describe gravitropism in both shoots AND roots

A

Shoots,
- IAA diffuse to lower side, more cell elongation on bottom of shoot.
- curve upwards
- Negative gravitropism

Roots
- IAA on bottom of root, inhibiting cell elongation
- root curves downwards
- Positive gravitropism

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

What is a reflex

A

Rapid, automatic response to protect organism from danger.

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

what three neurons are involved in the reflex arc?

A

Sensory neuron, Relay neurone, Motor neurone.

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

Kinesis

A

An organism changes the speed of movement and rate it changes direction.

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

How would an organism respond with kinesis when it has moved to an area of harmful stimuli?

A

Increase rate that it changes directions to return to favourable conditions.
After being moved from positive stimuli to negative stimuli.

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

Why would an organism reduce changes in direction?

A

straighter line = more likely to move to favourable stimuli.
when surrounded by negative stimuli

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

Give the 7 steps of a reflex arc

A
  • Stimulus
  • Receptor neuron
  • Sensory neuron
  • intermediate neuron
  • motor neuron
  • effector
  • response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why are reflex arcs important? (3)

A

Involary - don’t overload brain.

protect - not learnt, from birth

fast - shorter neuron pathway, few synapses, no decision making

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

What is meant when cardiac tissue is described as myogenic?

A

Initiates its own rhythm of contractions, without nervous stimulation.

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

Where is the sinoatrial node (SAN) located?

A

right atrium

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

where is the atrioventricular node located?

A

right atrium, near the border of right and left ventricle.

17
Q

Where is the bundle of his located?

A

Runs through the septum.

18
Q

Where are the purkyne fibres located?

A

in the walls of ventricles?

19
Q

What is the role of the SAN?

A

Wave of depolarisation across the atria causing it to contract.

20
Q

What pigment is found in rod cells?

A

Rhodipsis

21
Q

What is the role of rhodopsin/ iodopsin in rod/ cone cells

A

Broken down by light energy, creating generator potential

22
Q

Give three differences between rod and cone cells

A
  • rods produce a B/W image, cones in colour
  • rhodopsin found in rods, iodopsin found in cones
  • rods have low visual activity, cones have high
23
Q

Why do rod cells have a low visual activity?

Why is this important?

A

Many rod cells to one sensory neurone (retinal convergence), less able to separate light sources.

Generator potential more likely at low light intensity.

24
Q

How do iodopsin and rhodopsin differ?

A

Three types of Iodopsin (RGB) absorbing light at different wavelengths

Iodopsin is broken down at high light intensity

ONE cone cell attaches to ONE bipolar cell

25
Q

Describe and explain the distribution of rod and cone cells at the retina.

A

Fovellia is the point at which the most light is focused to (by lens) more cone cells are located here.
Most rod cells are positioned further away.

Light intensity is highest at fovellia, cone cells require high light intensity.

26
Q

What is the function of the pacinian corpuscle?
describe structure.

A

Pressure receptor located in deep in the skin.

connective tissue and gel surrounding neuron ending attached to sensory neuron. stretch mediated sodium channels.

27
Q

Describe how pacinain corpuscle establishes a generator potential in response to stimulus.

A

Sensory Neurone is located in centre of pacinain corpuscle, stretch-mediated sodium channels open when deformed. Allowing Na+ ions to enter.

28
Q

Describe how heart rate is controlled.

A
  • SAN releases wave of depolarisation, atria contracts
  • AVN releases another wave, ventricles does not contract, wave is stopped by non-conductive tissue
  • wave travels through bundle of his and this purkyne fibres
  • AVN transmits second wave, (allowing enough time for atria to pump blood into ventricles)
  • ventricles contract, starting from apex
  • cells re-polarise
29
Q

What controls heart rate?

A

medulla oblongata

30
Q

what effect does the sympathetic nervous system have on heart rate?

what effect does the parasympathetic nervous system have on heart rate?

A

increases the heart rate, more frequent waves

decrease, less frequent waves

31
Q

What receptors detect changes in PH and blood pressure?

Where are they found?

A

chemoreceptor and pressure receptors found in the aorta and carotid artery

32
Q

Why and how does the heart rate change in response to a change in PH in the blood

A

CO2 and lactic acid from respiration lower PH. increase heart rate to increase C02 lost at the alveoli. (more impulses via the sympathetic nervous system to SAN)

33
Q

Why and how does heart rate change in response to high blood pressure?

A

High blood pressure damages the wall of arteries. more impulses via parasympathetic system to decrease heart rate.

Blood pressure is too low, insufficient oxygen delivered. more impulses via the sympathetic nervous system.

34
Q

taxes

A

movement of entire body towards stimuli (positive), or away from stimuli (negative)

35
Q
A

Biology is for cool people (26 decks)

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