Brainscape's Knowledge GenomeTM

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


See full index

A-level Biology > Mass Transport In Plants And Animals > Flashcards

Mass Transport In Plants And Animals Flashcards

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

What is an open circulatory system?

A

Blood is not always held in blood vessels

Flow comes from movement / a pumping organ eg insects

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

What are the disadvantages of an open circulatory system?

A

Has a low pressure and so a slow blood flow

Movement affects the rate of flow

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

What is a close circulatory system?

A

Blood is always in vessels

Has a higher pressure and therefore a faster flow

Always for the rapid distribution of O2 and rapid removal of CO2

Allows for independent movement

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

Give an example of an animal with a single circulatory system

A

Fish

Blood flows from the body to the gills and back to the body

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

What are the benefits of a double circulatory system?

A

Allows blood to be depressurised before it reaches the body

Allows for the delivery of O2 and nutrients to and of CO2 and metabolic wastes from respiring tissues faster

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

How are arteries adapted for their function?

A

High blood pressure

Small lumen and smooth walls maintains the high blood pressure

Elastic tissue to allow for the stretch and recoil of walls to push blood along

Smooth muscle for the involuntary contractions

Thick layer of collagen for strength against the high pressure

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

How are arterioles adapted for their function?

A

Relatively high blood pressure

Smooth muscle

Contraction of muscle cause constriction of lumen to reduce the rate of flow

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

How are capillaries adapted for their function?

A

Low pressure and are hence thin

1 squamous cell thick endothelium

Small lumen so only one red blood cell at a time

Leaky allowing for the formation of tissue fluid

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

How are venules adapted for their function?

A

Thin layers of collagen and muscle

Some elastic tissue for recoil

Endothelium

Carries blood form the capillary bed to the veins

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

How are the veins adapted for their function?

A

Carry blood back to the heart

Low pressure

Thinner walls

Still contain smooth muscle and elastic tissue

Valves to prevent back flow

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

How is oxygen transported ?

A

Oxygen binds to haemoglobin in the red blood cells and is carried to respiring tissues through the blood

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

What is haemoglobin?

A

A quaternary protein made from 4 poly peptide chains

2x alpha and 2x beta chains

Contain an iron ion (Fe^2+) in the haeme group

4x haeme groups.

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

What is the role of haemoglobin?

A

To readily associate with oxygen at the surface where gas exchange takes place

To readily dissociate from oxygen at those tissues requiring it.

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

Explain the loading and unloading of oxygen with haemoglobin.

A
  1. At the gas exchange surface carbon dioxide is constantly being removed
  2. The pH is slightly raised due to the low concentration of CO2
  3. The high pH changes the shape of haemoglobin allowing it to bind to its first oxygen molecule
  4. This shape increases affinity for oxygen allowing 3 more molecules to bind to it (positive cooperativity)
  5. The oxygen is transported to respiring tissues via the blood
  6. CO2 is produced by respiring cells lowering the pH by producing carbonic acid
  7. The Lowe pH changes the shape of haemoglobin so it now has a lower affinity for oxygen
  8. Haemoglobin releases oxygen to the respiring tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is positive cooperativity?

A

The first oxygen molecule is hard to bind to haemoglobin

Once the first one does, haemoglobin now has a higher affinity for more oxygen molecules

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

What affect does carbon dioxide have on haemoglobin

A

At respiring tissues CO2 is produced

CO2 +H2O ——> H2CO3 (carbonic acid)

This lowers the pH which changes the shape of the haemoglobin molecule to one where its affinity for oxygen is lowered and oxygen dissociates from the haeme group.
(BoHR effect)

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

What is the BoHR shift?

A

Where the percentage saturation of oxygen (in the blood) is lower at a higher partial pressure of oxygen

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

What is tissue fluid?

A

Blood plasma which is forced out of capillaries by hydrostatic pressure and bathes the surrounding tissues.

(But no cells or plasma proteins)

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

What is in blood?

A

RBC’s (erythrocytes)
WBC’s (Leukocytes)
Platelets
Plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is in blood plasma?

A 
O2/CO2
Minerals
Glucose
Amino acids
Hormones
Plasma proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is tissue fluid formed?

A

Formed in the capillary beds

As blood flows through capillaries tissue fluid is forced out

This then bathed tissues and body cells
(Exchange of gases and nutrients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is lymph?

A

Similar composition to tissue fluid but also contains lymphocytes (produced in the lymph nodes)

Important for an immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the lymphatic system?

A

System which drains excess fluid out of tissues and returns it to the blood system via the subclavian vein (in the chest)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How is tissue fluid formed?

A
  1. Pumping of the blood creates hydrostatic pressure
  2. At the arteriole end the hydrostatic pressure is greater in the capillary than in the outside (tissues) and therefore causes water and solutes in the blood to be pushed out of the capillaries.
  3. Due to capillaries being 1 cell thick and therefore can only fit RBC’s . Their walls are leaky and so tissue fluid is forced out through the gaps.
  4. Once the tissue fluid has exchanged metabolic materials with tissues and cells (after bathing the cells). Most of the tissue fluid is returned back to the capillary
  5. Due to plasma proteins (too big to leave capillaries) lowering the water potential and the hydrostatic pressure is greater outside the capillaries than inside at the Venous end.
  6. Therefore tissue fluid drains back into the capillaries
  7. Excess fluid that is not returned is drained into the lymphatic system and returned to the blood closer to the heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do plasma proteins lower the water potential in the capillaries?

A

Plasma proteins are soluble and therefore dissolve into the fluid. This therefore lowers the water potential enabling tissue fluid to move back into the capillaries.

26
Q

Define myogenic?

A

Initiates its own contraction

27
Q

What is the flow of blood through the heart?

A 
Vena cava
Right atrium (atrioventricular valve)
Right ventricle
Pulmonary artery (semi lunar valve)
Lungs 
Pulmonary vein
Left atrium
Left ventricle
Aorta 
Body
28
Q

Explain the process of the cardiac cycle

A

Whole heart diastole:
Atria and ventricles are relaxed and so have a low blood pressure enabling blood to enter from the pulmonary vein and vena cava

Atrial systole:
Contraction of atria walls and recoil of the relaxed ventricle force blood from the atria at a higher pressure into the ventricles which have a lower pressure enabling them to fill.

Ventricular systole:
After a short delay and once the atrioventricular valves have shut, the ventricles contract and increase the blood pressure forcing blood out through the pulmonary artery and the aorta.

29
Q

Why does the left side of the heart have thicker muscle that the right?

A

The left ventricle has the thickest muscle to provide a strong enough contraction to pump blood around the whole body

30
Q

How do you calculate cardiac output?

A

Cardiac output = stroke volume X heart rate

Stroke volume- volume of blood moved in the left ventricle per heart beat

Heart rate- beats per minute

31
Q

How do you measure heart rate?

A

Using an ECG

Electro cardio gram

32
Q

What nodes in the heart controls the heart rate?

A

SAN (sino atrial node)- pacemaker

AVN (atrioventricular node)

33
Q

How does the cardiovascular centre control heart rate?

A

The medulla oblongata has two centres which control heart rate

One increase heart rate linked to the SAN node via the sympathetic nervous system

One decrease heart rate linked to the SAN via the parasympathetic nervous system

34
Q

What receptors may detect a change causing a change in heart rate?

A

Chemoreceptors

Baroreceptors

Found in the walls of the carotid artery and aorta

35
Q

How do chemoreceptors cause the heart rate to change?

A

When tissues respire they produce CO2 which lowers the pH of the blood.

Chemoreceptors in the wall of the carotid artery and aorta detect this change and increase the frequency of impulses to the cardiovascular centre in the brain

This increases heart rate

36
Q

How do baroreceptors cause a change in the heart rate?

A

When blood pressure increases or decreases

Baroreceptors in the wall of the carotid artery and aorta detect this change and increase the frequency of impulses to the cardiovascular centre in the brain

This increases heart rate

37
Q

How is the heart rate controlled?

A
  1. Receptors in the carotid artery or aorta detect a change in pressure or pH
  2. This sends more/fewer impulses to the medulla oblongata in the cardiovascular centre of the brain.
  3. This increases the frequency of impulses send down the para/sympathetic nervous system (accelerator or vagus nerve) to the SAN
  4. This increases the rate of impulse sent from the SAN to the AVN and increases heart rate.
38
Q

How is the heart rate increased?

A
  1. More frequent impulses are sent from the medulla oblongata down the accelerator nerve of the sympathetic nervous system to the SAN
  2. The SAN sends out a wave of excitation causing the atria to contract.
  3. A layer of non conductive tissue prevents the wave from crossing to the ventricles
  4. The wave of excitation reaches the AVN
  5. After a short delay this conveys a wave of electrical impulse between the ventricles down the purkinjy fibres (bundle of his)
  6. The bundle of his conducts the wave through the septum to the base of the ventricles
  7. The ventricles contract from the bottom up pumping blood around the body and heart rate is increased .
39
Q

What are some artificial controls of heart rate?

A

Pacemakers

40
Q

Why is it important to have a delay between the SAN and the AVN nodes?

A

To allow time for the ventricles to fill with blood and the valves to shut.

41
Q

What resources do plants need from their environment?

A 
O2
Water
Sugars
Minerals
Amino acids
42
Q

What is the function of the xylem?

A

Transport of water through the plant via the transpiration stream

43
Q

What is the function of the phloem?

A

To transport sugars and minerals from sources to sinks

44
Q

What is the structure of the xylem?

A

Continuous columns of cells with no cell contents to allow space for water.
The walls are strengthened by lignin which also waterproofs the walls

45
Q

What is the structure of the phloem?

A

Thin walls with little cytoplasm and no nucleus / other organelles

Contain sieve plates

Companion cells have a large nucleus, dense cytoplasm and lots of mitochondria for the process of active loading

46
Q

How does water move through cells?

A

Apoplast pathway- between the cells and through cell walls until it hits the casparian strip

Symplast pathway- through cytoplasms of cells

Vacuolar pathway- through vacuoles

47
Q

What is transpiration?

A

Loss of water vapour from aerial parts of plants ( leaves) some through cuticle but most through stomata

48
Q

What is the purpose of the stomata?

A

Open to allow gas exchange with the environment

When open enable water to be lost through evaporation

49
Q

How does the transpiration stream work?

A

Root pressure enables water to move up the stem from high hydrostatic pressure to a lower hydrostatic pressure.

Helped by the transpiration pull (cohesion) and capillary action (adhesion)

50
Q

How does water enter the root hair cell?

A
  1. Ions are actively transported into the root hair cell
  2. This reduces the water potential in the cell so water can move in via osmosis
  3. Water moves along the cells via the various pathways until it hits the xylem
  4. High concentration of ions in the cells so will diffuse into the xylem
  5. Lowers the water potential so water moves in via osmosis
51
Q

What is plasmodesmata?

A

Doorways between cells in a plant

52
Q

What is translocation?

A

Movement of assimilates throughout the plant

53
Q

What are assimilates?

A

Substances made by the plant using substances form the environment

54
Q

What is a source

A

Place where sucrose is made and loaded into the phloem

55
Q

What is a sink?

A

Place where sucrose is used and removed from the phloem

56
Q

Give examples of sources

A

Leaves and roots

57
Q

Give examples of sinks

A

Roots and growing regions

58
Q

Explain the process of active loading

A

1 H+ ions are pumped out of the companion cell via active transport

  1. The co transport of H+ ions and sucrose brings sucrose into the companion cell via facilitated diffusion
  2. Diffusion of sucrose from the companion cells into the phloem
  3. Water follows into the phloem by osmosis (bulk flow)
  4. This generated hydrostatic pressure enabling sucrose to be transported to the sinks
59
Q

How is sucrose unloaded at sinks?

A

Via diffusion or active transport

60
Q

What are he differences between translocation and transpiration?

A 
Translocation:
Active process
Hydrostatic pressure
Push action
Altered by poisons
Transpiration:
Passive process
Tension
Pull action
Is not altered by poisons
61
Q

What experiments are done to investigate transport in plants?

A

Ringing experiments:
Bark enclosed a layer of phloem which extends around the stem.
This is removed.
Areas of sugars (sources) keep growing
Sinks die
Conclusion that phloem is responsible for transport of sucrose

Tracer experiments:
Using radioactive isotopes

A-level Biology (23 decks)

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