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Mine Year 13 Alevel Biology > 6 Organisms respond to changes in their internal and external environments (A-level only) > Flashcards

6 Organisms respond to changes in their internal and external environments (A-level only) Flashcards

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1
Q

What is and how is restring potential maintained?

A

Resting potential is the difference in electrical charge between outside and inside of neurone when an Impulse isn’t being conducted (-70mv)
Maintained by Sodium-Potassium Pump

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2
Q

What and why is needed for sodium potassium pump and how many ions are inside and outside neurone and why is there more of one ion outside the neurone?

A

ATP is needed for Sodium-potassium pump due to involving Active transport.
3Na+ outside neurone and 2K+ inside neurone.
K+ ions diffuse out due to it more permeable for K+ leaving then Na+ entering.

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3
Q

How is action potential formed? Name 1-2
[Hint 5 steps]

A

1)Impulse received from receptors causing Na+ channel to open so Na+ enter neurone causing depolarisation. If depolarisation reaches threshold causes voltage gated Na+ activated leading to higher influx causing action potential.

2)When action potential reached voltage gated Na+ channel close while Voltage gated K+ channels open so repolarisation occurs K+ leave neuron.

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4
Q

How is hyper polarisation caused and how does this causes resting potential?

A

When most of K+ leave neurone causes hyper-polarisation VOLTAGE GATED K+ CHANNEL CLOSE
Sodium-Potassium pump returns neurone back to its resting potential

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5
Q

What type of response is action potential?

A

All or nothing responses.

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6
Q

What the purpose of the type of response action potentials are and how is it caused?

A

Action potentials purpose is to same voltage is reached every time and is important maintaining rates if impulse.
This caused by action potential depolarises axons to same voltage by voltage gated Na+ channel

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7
Q

What is refractory period and what is the purpose?
[Hint its to do with action potential]

A

Refractory period is period in action potential when axon can’t be depolarised to intimate another action potential
1)Limits frequency of action potential
2)Ensures action potential travel in one direction

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8
Q

What transmission of action potential in Non-Myelinated neurone? What is bad about it?

A

When depolarisation occurs voltage gated Na+ channel open further down axon by the time depolarisation has spread part of NEURONE has already been polarised
Non-Myelinated depolarisation occurs along WHOLE LENGTH OF AXON/Lamallae

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9
Q

Transmission of action potential in myelinated neurone?
Advantages of this

A

Action potential ONLY occurs at Nodes on Ranvier, action potential “jumps from node to node’ quicker saltory conducted
Myelination provides insulation

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10
Q

Factors that affect speed of impulse

A

1)Myelination increases speed as salrtory conduction occurs
2)Axon diameter wider axon=Faster Impulse
3)Increased in temp=Increased in speed of impulse however only certain temp due to denture of protein

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11
Q

Give the 3 steps of Transmission of Cholingeric Synapse.

A

1)Action potential arrives at synaptic knob depolarise it, causing voltage gated Ca2+ to open allowing Ca2+ diffuse into synaptic knob, a higher influx of Ca2+ into synaptic knob causes vesicle containing acetylcholine fuse with pre-synaptic membrane
2)Acetylcholine released into synaptic cleft by endocytosis, acetylcholine bind to Cholingeric receptors causing voltage gated Na+ to open on post synaptic membrane
3)Na+ diffuse in causing depolarisation, if depolarisation reaches threshold potential action potential formed.

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12
Q

How is continuous impulse stopped in Transmission of Cholingeric Synapse?

A

Acetylcholine removed from synaptic cleft and degraded by Acetylcholine esterase to prevent continuous impulse
Products transfers into PRE-SYNAPTIC Neurone and Na+ channel close allowing post-synaptic neurone to reach resting potential

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13
Q

How can Cholingeric synapse can be inhibited ?

A

Cl- move into POST-SYNAPTIC neurone and K+ move out causing membrane potential reach causing hyperpolarisation so action potential unlikely

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14
Q

What is Summation ?

A

Rapid build up of neurotransmitter to help generate action potential.

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15
Q

Give the 2 types of Summation?

A

Temporal Summation: 1 Neurone release lots of neurotransmitters repeatedly over short period so threshold value exceeds

Spatial Summation: Many neuronetransmitters collecting combining neurotransmitters to exceed threshold potential

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16
Q

What is the first thing that happens in the sliding filament theory?

A

Action potential travels to muscle fibres and depolarises the SACROLEMMA by T-Tubules causing the release Ca2+ from SarcoPLASMIC Reticulum

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17
Q

In sliding theory filament what does the Ca2+ do and what does it cause?

A

Ca2+ bind to tropomyosin molecules causing them to expose myosin binding site on the actin filament causing Actin-Myosin(head) cross bridge formed upon Actin and Myosin binding together causing a POWER STROKE

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18
Q

In sliding filament Theory what does power stroke do?

A

Power Stroke causes a cross bridge rotate towards centre of sacromere

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19
Q

In Sliding Filament Theory what causes the Myosin head to detach And what does this cause?

A

ATP is hydrolysed by ATP hydralyse to detach the myosin head ALLOWING REATTACHMENT at further site causing the Sarcomere to shorted Causing Muscle contraction

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20
Q

In Sliding Filament Theory what happens when the impulse stops?

A

When the impulse stops Ca2+ is actively transported back into the Sarcoplasmic Reticulm this allows Tropomyosin to block the Actin Filament from binding to myosin so muscle contraction stops.

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21
Q

What the Acronym to remember in Muscle Contraction?

A

dArk=A bands
LiGHT=I bands

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22
Q

What is the Thin filament? (Binding pattern of skeletal Muscle)

A

I band= Thin= Actin

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23
Q

What is the middle of the I band and what is it ?

A

Middle of I band= Z line= zLINE is the sarcomere

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24
Q

What is A band?

A

A band is Actin and Myosin so it is thick and thin filaments

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25
Q

What is the thick filament and what is the thin filament?

A

Thick Filament=Myosin
Thin Filament= Actin

26
Q

What is in the middle of A Band?

A

In the middle of the A band is the H-Zone and the Hzone is only myosin

27
Q

What is present in the H-Zone

A

Only myosin

28
Q

Shortcut of what happens in Sliding Filament Hyothesis?

A

Thick and Thin Filaments do not change in length
A BAND remains constant so A bands same length
I bAND dECREASES
Z LINE MOVE TOGETHER so Sacromere gets shorter

29
Q

[Muscle Contraction] Where is Slow Twitch located and what is the structure of Slow Twitch and what is general properties?

A

Location is CALF MUSCLES
Structure is HIGH CONCENTRATION OF MYOGLOBIN WHICH MEANS MANY MITOCHONDRIA and RICH BLOOD SUPPLY
2 general Properties: Contracts slowly and Respires Aerobically for long period time

30
Q

[Muscle Contraction] Where is the location of Fast Twitch, what is the structure and the general properties?

A

Location is the BICEPS
The structure is THICKER-MORE MYOSIN and High storage of GLYCOGEN
1) General properties is it contracts faster in short burst

31
Q

[Muscle Contraction] What acronym help to help you identify which Twitch is which?

A

Slow Twitch=S-SLow
Fast Twitch=F-Faster

32
Q

What is the definition of homeostasis?

A

Homeostasis is the maintenance of Constant internal environment

33
Q

What happens if you have too low temperature?[Homeostatis

A

Not enough kinetic energy so slow formation of Enzyme Substate Complex

34
Q

What happens if too high temperature?

A

Denatures of Enzyme

35
Q

What happens if pH levels too high or low

A

DEVIATION from Optimum pH causes enzyme to denture

36
Q

What happens if Blood Glucose Concentration too low?

A

Causes Cell Death as glucose required as a substate for respiration

37
Q

What happens if Blood Glucose Concentration too High?

A

Blood WATER Potential DECREASES
Water leaves by osmosis causes Cells to SHRIVEL UP
As water leaves cell and enter blood WATER POTENTIAL OF BLOOD IS VERY HIGH sometimes water moves back into cell causing cell to BURST

38
Q

What is phototropism?

A

Shoots and Roots grow in response to light.

39
Q

What happens if Light hits the tip of the plant?
[Phototropism] [SHOOT]

A

1.When light hits tip of plant causes IAA to diffuse to shaded side of SHOOT promotes growth+cell elongation causes shoot to bend towards light source
Positive Phototropism

40
Q

Describe Phototropism in Roots.

A

IAA diffuses towards shaded side of the root.
INHIBITS GROWTH AND CELL ELONGATION
Root bends away from light-Negative Phototropism.

41
Q

What is Gravitropism?

A

Gravitropism is when Shoots and Roots grow in response to gravity.

42
Q

Describe Gravitropism In shoots.

A

Gravity acts on Shoots and IAA diffuses towards BOTTOM due to gravity. Increase in conc=Promotes cell growth and elongation so shoots bends and grows AGAINST GRAVITY(upwards)

43
Q

Describe Gravitropism in roots.

A

IAA diffuses towards bottom due to gravity.
IAA inhibits growth and cell elongation so root bends and grow TOWARDS GRAVITY and roots goes downwards=POSITIVE GRAVITROPISM

44
Q

Definition of Taxes.

A

Directional response in movements of stimuli

45
Q

Definition of kinesis

A

Non-Directional response to movement due to stimuli

46
Q

Definition of Reflexes.

A

Extremely rapid response that doesn’t require thought.

47
Q

How does the impulse move in reflexes?

A

1.Detected By receptors send signals to Sensory neurone
Then to spinal cord
Passes to RELAY NEURONE THROUGH SYNAPSE
Synapse to MOTOR NEURONE then to effector

48
Q

Where is Pancinian Corpuscule situated?

A

Often Situated deep in skin at fingers and feet.

49
Q

Explain why and how is resting potential maintained at Pancinian Corpuscle?

A

Resting potential maintained because Channel is too narrow for Na+ to diffuse so resting potential maintained.

50
Q

How is Pancinan Corpuscle stimulate\What is first stage?

A

When stimulated(tap on the arm) Lamellae are deformed and press on sensory Nerve Ending
Causes Sensory neurone CELL MEMBRANE to STRECH

51
Q

What is generated and how is … generated in Pancinian Corpuscle?

A

When Sensory Neurone Cell Membrane Stretched Na+ Channel open makes cell membrane more PERMEABLE to Na+
Na+ diffuses in creating GENERATOR POTENTIAL

52
Q

How is Action Potential Formed in Pancinian Corpuscle?

A

If Generator Potential reaches threshold causes Action Potential to be produced.

53
Q

What pigment is present in Rods?
What is rods and where is it found?
What is function of Rods?

A

Rods have Rhodopsin Pigment.
Rods are found in the retina and evenly distributed across the eye.
Function of eye is to process images in black and white.

54
Q

What are two properties of Rods?
Why do these properties occur in Rods?

A

Two properties of Rods are:
1.Rods detect light OF very low intensity
2.Rods cells GIVE low visual Acuity
These properties occur due to Many/Lots of Rods connected to ONE sensory neurone.

55
Q

How is Rhodopsin broken down?
[Explain all]

A

As Rhodopsin have many rods connected to one sensory neurone it doesn’t take a lot of energy to break down Rhodopsin due to Spacial Summation(Retinal Convergence)

56
Q

What pigment and how many cones cells are there?

A

Cone cells have Iodopsin Pigment.
There are three types of Cone cells that contain DIFFERENT TYPE of Iodopsin pigment
Different Iodopsin pigment are Red,Green and Blue which absorb different wavelengths of light.

57
Q

What are the properties of Cones?
Why do these properties occur?

A

1.Cones only respond to High Light intensity so no spacial Summation.
2.Have High visual acuity.
These properties occur due to one cone cell is connected to (one) bipolar cell.

58
Q

How is Iodopsin broken down?

A

Iodopsin is only broken down if there is a high light intensity as there is NO SPACIAL SUMMATION.
SO action potentials only generated with enough light (more than rods)

59
Q

What is the distribution of Cones and Rods?

A

Most Cones cells located near Fovea-so highest concentration at Fovea due to high light intensity.
Rods are evenly distributed across the eye.
Both found in the RETINA.

60
Q

What is the consequence of Low visual acuity?

A

Low visual acuity means can’t distinguish between different light sources.

61
Q

What causes Spacial Summation?
Which photoreceptors has Spacial summation and how does it occur?

A

Spacial Summation occurs in Rods.
Spacial Summation when neurotransmitters collectively combine to overcome threshold value to generate action potential.
Spacial Summation occurs in Rods due to lots of rods connected to One sensory neurone.

Mine Year 13 Alevel Biology (44 decks)

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