SB8 - Exchange and Transport in Animals Flashcards Preview

Edexcel GCSE Biology (9-1) > SB8 - Exchange and Transport in Animals > Flashcards

Flashcards in SB8 - Exchange and Transport in Animals Deck (55)
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1
Q

SB8a - What are all the chemical reactions in your body known as?

A

Your metabolism

2
Q

SB8a - What must happen to waste products in your body?

A

They must be excreted so that they don’t cause any problems

3
Q

SB8a - What are some examples of waste products in your body?

A
  • Urea
  • Carbon dioxide
4
Q

SB8a - What are some examples of substances that your body takes in?

A
  • Glucose
  • Amino Acids
  • Oxygen
5
Q

SB8a - Through what process do most substances move around the body?

A

Diffusion

6
Q

SB8a - What do diffusion surfaces have to be like?

A
  • Thin: So particles don’t have to diffuse far
  • Large surface area: More room to allow particles to diffuse through
7
Q

SB8a - Why does blood need to continue flowing for substances to continue moving?

A
  • Oxygen and glucose diffuses out and carbon dioxide diffuses in at a certain point
  • The blood then continues to flow
  • This means that concentration gradient at the diffusion point is maintained
  • This allows diffusion to continue happening
8
Q

SB8a - Why do multi-cellular organisms need transport systems?

A

Transport systems are needed to take substances towards the centre of the body as diffusion from the outside to the centre of the body would take too long

9
Q

SB8a - What is the circulatory system made of?

A
  • The heart
  • Veins
  • Arteries
  • A network of fine capillaries
10
Q

SB8a - How do you calculate surface area : Volume ratio?

A

Surface area ÷ Volume

11
Q

SB8a - Why does SA:V ratio affect rate of diffusion?

A

A higher surface area means more area through which particles can diffuse, but a larger volume takes longer to be filled up

12
Q

SB8a - Why can’t cells be infinitely large?

A
  • As cells get bigger, their SA:V ratio gets smaller.
  • This means it will take longer and longer for substances to enter the cell
13
Q

SB8a - What adaptation do the lungs have?

A
  • The lungs have millions of aveoli which increase the surface area while maintaining the volume.
  • This increases the SA:V ratio increasing rate of gas exchange
14
Q

SB8a - What adaptations do alveoli have?

A
  • One cell thick wall allowing for easy diffusion
  • Large SA:V ratio due to its shape
15
Q

SB8b - What is 1dm3 equal to?

A

1000cm3

16
Q

SB8b - How do you calculate concentration?

A

Concentration (g/dm3)

=

mass of solute (g) / volume of solution (dm3)

17
Q

SB8b - How does concentration gradient affect rate of diffusion?

A

The steeper the concentration gradient (Greater the difference in concentration) the higher the rate of diffusion due to a larger net movement of particles in the same time

18
Q

SB8b - What is the relationship between concentration gradient and rate of diffusion?

A

They have a linear directly proportional relationship

rate of diffusion ∝ concentration difference

19
Q

SB8b - How does surface area affect rate of diffusion?

A
  • A higher surface area means that particles have more area to pass through.
  • This means that more particles can move through a membrane at one time.
  • This increases the overall rate of diffusion but doesn’t change the speed at which particles move
20
Q

SB8b - What is the relationship between surface area and rate of diffusion?

A

rate of diffusion ∝ surface area

21
Q

SB8b - How does the thickness of the membrane affect rate of diffusion?

A
  • A thicker membrane means that particles have a longer distance to travel.
  • This means that the rate of diffusion will be slower
22
Q

SB8b - What is the relationship between thickness of membrane and rate of diffusion?

A

rate of diffusion ∝-1 thickness of membrane

or

rate of diffusion ∝ 1 ÷ thickness of membrane

23
Q

SB8b - What is Fick’s law?

A

Fick’s law shows the relationship between the three factors that affect rate of diffusion.

24
Q

SB8c - What are the jobs of each of the components of the circulatory system?

A
  • Heart: Pumps blood around the body
  • Arteries: Take blood away from the heart
  • Capillaries: Fine networks taking blood to and through tissue
  • Veins: Takes blood back to the heart
25
Q

SB8c - What are the adaptations of arteries?

A
  • Narrow lumen (tube)
  • Thick elastic and muscle fibres
  • This helps it withstand high pressures
  • Recoil due to elasticity helps the blood continue to be pumped
26
Q

SB8c - What are the adaptations of capillaries?

A
  • Capillaries have very narrow lumen (tubes) as they are carrying very little blood
  • They have walls only 1 cell thick to allow for faster diffusion
27
Q

SB8c - What are the adaptations of veins?

A
  • Valves to ensure blood flows in one direction
  • Thin walls as pressure is low
  • Wide lumen (tube) to reduce pressure
28
Q

SB8c - Why are valves only necessary in veins?

A
  • Arteries have blood flowing at a high pressure and this ensures blood flows in the right direction
  • This is helped by the elasticity
  • Veins have blood flowing at a low pressure and so blood isn’t forced to travel in the right direction
  • Valves ensure blood flows in the correct direction
29
Q

SB8c - How do valves work?

A
  • Valves are like one way doors
  • Skeletal muscles help blood move along the veins
  • When blood is flowing in the correct direction, valves are open
  • When muscles are relaxed, blood can easily flow in the wrong direction
  • The moment any blood starts to flow in the wrong direction, the valves close, stopping blood from flowing this way
30
Q

SB8c - What is another word for red blood cells?

A

Erythrocytes

31
Q

SB8c - What are the components of blood?

A
  • Erythrocytes (RBC)
  • White blood cells
  • Platelets
  • Plasma
32
Q

SB8c - What do erythrocytes do?

A
  • Packed with haemoglobin which oxygen binds to allowing it to be transported
  • Biconcave shape to increase surface area for effective diffusion
  • No nucleus to make more space for haemoglobin and oxygen
  • Will turn a brighter shade of red when more oxygen is bound
33
Q

SB8c - What are the two types of white blood cells and what do they do?

A
  • Phagocytes: Surround and consume foreign cells
  • Lymphocytes: Release antibodies to attack foreign cells
34
Q

SB8c - What does plasma contain?

A
  • Water
  • Carbon dioxide
  • Glucose
  • Urea
  • Other dissolved minerals
35
Q

SB8c - What do platelets do?

A

Platelets are tiny fragments of cells that produce substances to allow the blood to clot when injured

36
Q

SB8d - What is a heart attack?

A
  • When blood stops flowing through the heart properly, it can damage the heart muscles.
  • This can cause a heart attack, also known as cardiac arrest. If the heart stops working completely, an electric shock (i.e. a defibrillator) can get it to work again
37
Q

SB8d - What is the structure of the heart?

A
38
Q

SB8d - How does blood move around the heart?

A
  • Firstly, blood from the upper body enters the heart through the superior vena cava; while blood from the lower body enters through the inferior vena cava
  • This travels into the right atrium and through the ventricle
  • The blood leaves through the pulmonary artery into the lungs where it becomes oxygenated
  • It then re-enters the heart through the pulmonary veins
  • Here it travels through the valves and left ventricle before leaving through the aorta
39
Q

SB8d - What is important to remember when looking at diagrams of a heart?

A

You are looking at the diagram as if you are looking at a person (left on right and v/v)

40
Q

SB8d - Why does the left side of the heart have thicker muscle?

A

It has to pump blood to all around the body rather than just to the lungs and so requires more strength

41
Q

SB8d - What is stroke volume?

A

The volume of blood pushed into the aorta per beat

42
Q

SB8d - What is the formula for cardiac output?

A

Cardiac output (litres/min)

=

Stroke volume (litres/beat) x heart rate (beats/min)

43
Q

SB8e - What does your body require a constant supply of energy for?

A
  • Moving
  • Keeping warm
  • Production and breaking down substances
44
Q

SB8e - What is cellular respiration?

A
  • A series of reactions that uses glucose to provide energy for the body.
  • It is exothermic
45
Q

SB8e - Where in the cell does respiration occur?

A

In the mitochondria

46
Q

SB8e - Describe the process of cellular respiration from breathing in to cell to breathing out

A
  • Breathing in adds oxygen into the blood flow
  • As the blood passes the small intestine, it absorbs glucose from digested food
  • When the blood reaches a cell, the cell takes in the glucose and oxygen in exchange for carbon dioxide and water
  • The blood takes this carbon dioxide back to the lungs where it is breathed out
47
Q

SB8e - What is the word equation for respiration?

A

Glucose + Oxygen → Carbon dixoide + Water (+ energy)

48
Q

SB8e - Why is respiration exothermic?

A

It releases energy to its surroundings and the products have less energy than the reactants

49
Q

SB8e - Why do you breathe faster when exercising?

A
  • Faster breathing allows more oxygen to be breathed in and diffused into the blood
  • This provides more oxygen for cells to respire more effectively
  • It also gets rid of more carbon dioxide
50
Q

SB8e - What is the word equation for anaerobic respiration?

A

Glucose → Lactic acid + (+energy)

51
Q

SB8e - Why may anaerobic respiration occur?

A
  • Anaerobic respiration occurs in a deficit of oxygen
  • During strenuous exercise, your cells may need more oxygen than can be provided leading to anaerobic respiration occuring
52
Q

SB8e - What are the problems with anaerobic respiration?

A
  • It produces less energy than aerobic respiration
  • Lactic acid building up in muscles can cause cramps and damage
  • Muscles can tire quickly
53
Q

SB8e - Why may anaerobic respiration be important for a prey suddenly escaping its predator?

A

Anaerobic respiration can provide short sharp bursts of energy without needing a sudden increase in oxygen supply

54
Q

SB8e - Why may heart/breathing rates remain high after exercise?

A
  • Extra oxygen is needed to replace what has been lost
  • Extra oxygen is required to provide energy to get rid of lactic acid
55
Q

SB8e CP - Describe how you would investigate rates of respiration in small organisms

A
  • Set up the test tube with a bung attacthed to it so that:
    • A CO2 absorber (e.g soda lime) is at the bottom
    • Cotton wool is on top
    • The organism(s) are on this
    • The blob of coloured liquid is right at the start
    • The 0cm mark of the ruler is lined up with the liquid
  • This is called a simple respirometer
  • You measure how far along the capilary tube the blob moves every so often
  • Distance moved ÷ time = rate of respiration
  • Alter the temperature to see how this affects the rate of respiration
  • This is your independant variable, so ensure you keep everythign else the same as they are your control variables
  • To set up a control experiment for this, you would have the same set-up with no organisms