Exchange and transport in animals

Give 6 exchanged substances

Oxygen

Carbon dioxide

Water

Dissolved food molecules

Mineral ions

Urea

Where does exchange of substances happen?

Cell membrane

What are the 3 transport processes?

Diffusion

Osmosis

Active transport

Give an example of a transport system in animals

Circulatory system

Give an example of a transport system in plants

Xylem and phloem

Give the 3 adaptations of specialised exchange surfaces to maximise exchange

1. Large surface area

2. Thin membrane

3. Having an efficient blood supply/being ventilated (in animals)

Why does having a large surface area maximise exchange?

The greater the surface area, the more particles can move through, resulting in a faster rate of exchange

E.g. alveoli in lungs create a large SA for gas exchange

Why does having a thin membrane maximise exchange?

Provides a short diffusion pathway, allowing the process to occur faster

E.g. capillary walls near the lungs are extremely thin for gas exchange

Why does having an efficient blood supply/being ventilated maximise exchange/transport?

Creates a steep concentration gradient so diffusion occurs faster

E.g. lungs supply oxygen to blood constantly for the body to exchange for carbon dioxide, so concentration gradient is always steep

Surface area : volume ratio calculation

surface area/volume

What are alveoli?

Tiny air sacs in the lungs where gas exchange occurs

Explain 3 adaptations of alveoli for gas exchange between lungs and blood

1. Small and arranged in clusters, creating a large surface area for diffusion to take place

2. The surrounding capillaries provide a large blood supply, maintaining the concentration gradient

3. Thin walls so short diffusion pathway

What are the 3 factors affecting the rate of diffusion?

Surface area

Concentration gradient

Diffusion distance

Explain how concentration gradient affects rate of diffusion

The greater the difference in concentration, the faster the rate of diffusion

Explain how diffusion distance affects rate of diffusion

The smaller the diffusion pathway, the faster the rate of diffusion because there is less obstacles to get through

Explain how surface area affects rate of diffusion

Greater surface area= faster rate of diffusion because there are more entry and exit points for particles to cross

Explain how temperature affects rate of diffusion

Higher temperature=faster rate of diffusion because particles gain kinetic energy so will move faster through the membrane

Rate of diffusion calculation

Fick's law:

rate of diffusion ∝ (surface area x concentration difference) / thickness of membrane

What is the blood made up of? (4 things)

Red blood cells

White blood cells

Plasma

Platelets

Function and adaptations of red blood cells

FUNCTION:

Carry oxygen molecules from the lungs to all cells in the body

ADAPTATIONS:

1. Bioconcave disc shape provides a larger surface area : volume ratio

2. No nucleus to make more room for oxygen

Function and adaptations of white blood cells (phagocytes and lymphocytes)

FUNCTION:

Part of the immune system- body's defence against pathogens

ADAPTATIONS:

Different types:

1. those that produce antibodies

2. those that engulf and digest pathogens

3. those that produce antitoxins to neutralise toxins produced by microorganisms

Role of plasma

the liquid that carries the components of the blood e.g. red blood cells, hormones, glucose

Role of platelets

Small fragments of cells

Help the blood clot at the site of a wound to prevent excessive bleeding

Prevents microorganisms from entering and infecting

What are the 3 main types of blood vessel?

Arteries

Veins

Capillaries

Describe the function and adaptations of arteries

FUNCTION:

Carry blood AWAY from heart

ADAPTATIONS:

1. Have thick musclar walls containing elastic fibres to withstand the high pressure of blood being pumped

2. Narrow lumen (tube) to maintain high blood pressure

Describe the function and adaptations of veins

FUNCTION:

Carry blood TOWARDS the heart

ADAPTATIONS:

1. Lumen is wide to allow the low pressure blood to flow through

2. Contain valves to prevent the backflow of blood as it is under low presser

Describe the function and adaptations of capillaries

FUNCTION:

Allow the blood to flow very close to cells to enable substances to move between them

ADAPTATIONS:

1. One cell thick walls to create a short diffusion pathway

2. Permable walls so substances can move across them

Explain the adaptations of the heart

1. Muscular walls to provide a strong heartbeat

2. Four chambers that separate the oxygenated blood from the deoxygenated blood

3. Valves to prevent the backflow of blood

4. The muscular wall on the left ventricle is thicker because blood needs to be pumped all around the body, rather than just to the lung like the right ventricle

Describe the pathway of blood through the heart

1. Blood flows into the right atrium through the vena cava, and though the left atrium through the pulmonary vein

2. the atria contract forcing the blood into the ventricles

3. The ventricles then contract, pushing the deoxygenated blood in the right ventricle into the pulmonary artery to be taken to the lungs, and the oxygenated blood in the left ventricle to the aorta to be taken around the body

Which part of the heart does the deoxygenated blood flow through?

Right, to be taken to the lungs

(vena cava --> right atrium-->right ventricle --> pulmonary artery)

Which part of the heart does the oxygenated blood flow through?

Left, to be taken around the body

(pulmonary vein --> left atrium --> left ventricle --> aorta)

What type of reaction is cellular respiration?

Exothermic

What is the purpose of respiration?

to release energy for metabolic processes

What are the two types of respiration?

Aerobic

Anaerobic

Describe the process of aerobic respiration

The complete breakdown of glucose

Uses oxygen

Yields the most energy

Occurs in the mitochondria

Give the word and symbol equations for aerobic respiration

Oxygen + glucose --> carbon dioxide + water (+ATP)

O₂ + C₆H₁₂O₆ --> CO₂ + H₂O

Describe the process of anaerobic respiration

Occurs when there is not enough oxygen, resulting in the incomplete breakdown of glucose

Doesn't yield as much energy as aerobic respiration

In animals, produces lactic acid (resulting in oxygen debt- the amount of oxygen needed to break down the lactic acid later)

In plant/yeast cells, produces ethanol and carbon dioxide

Give the word and symbol equations for anaerobic respiration in animals

Glucose --> lactic acid (+ATP)

C₆H₁₂O₆ --> 2C₃H₆O₃

Give the word and symbol equations for anaerobic respiration in plants/yeast

Glucose --> ethanol + carbon dioxide (+ ATP)

C₆H₁₂O₆ --> 2C₂H₅OH

Describe the CP done to investigate the rate of respiration in living organisms

1. put maggots in a test tube and cover test tube with a bung, except for a tube coming out

2. measure the amount of oxygen produced by the maggots over a set amount of time

Cardiac output calculation

cardiac output = stroke volume x heart rate