Biology- Topic 8 Exchange and transport in animals, Y10

Respiration

process where cells release energy

aerobic respiration

oxygen + glucose > carbon dioxide + water + energy

aerobic respiration (chemical equation)

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy

what type of reaction is aerobic respiration

EXOTHERMIC reaction (releases heat energy)

where does aerobic respiration take place

mitochondria

when do organisms use anaerobic respiration

when there isn’t enough oxygen for aerobic respiration

Anaerobic Respiration

glucose > lactic acid + (energy)

where does anaerobic respiration take place

in the cytoplasm

Substances exchanged in organisms

-oxygen
-water
-dissolved food molecules (glucose)

-carbon dioxide
-urea

CORE PRACTICAL: Respiration Rate in Living Organisms

Independent variable: Temperature (water bath)
Dependent variable: distance moved by coloured liquid
Control Variable: mass of organisms, volume of soda lime, time

What happens to the red liquid in the CORE PRACTICAL

• Liquid moves towards the maggots because as they respire oxygen is used up

what does soda lime do in the practical

soda lime absorbs carbon dioxide

diffusion

movement of particles from high concentration to low concentration

How does SURFACE AREA effect diffusion rate

the larger the surface area, the faster the diffusion since there is more area for diffusion

How does CONCENTRATION effect diffusion rate

the larger the concentration the faster the diffusion since there are more particles to diffuse

How does MEMBRANE THICKNESS effect diffusion rate

as thickness increase, diffusion decreases because there are more particles to diffuse

Fick’s Law

$$\text{Rate of Diffusion} \propto \frac{\text{Surface Area} \times \text{Concentration Difference}}{\text{Thickness of Membrane}}$$

what is SA:V

Surface Area : Volume
- the larger the organism the smaller the ratio
- divide both sides by volume

where does gas exchange take place

between the alveoli and blood capillaries

Adaptations of the Alveoli

• 480 million alveoli > huge surface area

• wall of Alveoli and capillaries are 1 cell thick

• Steep Concentration Gradient > blood is constantly moving

what are the 4 blood components

• red blood cells

• blood plasma

• white blood cells

• platelets

Blood plasma

• 55% of blood

• straw yellow liquid

• transports other components + dissolved substances (glucose)

Red Blood cells

• 45% of blood

• transports oxygen and carbon dioxide around body

• bioconcave for larger SA

• No nucleus for more space for haemoglobin (carries oxygen)

White Blood Cells

• < 1% of blood

• kills bacteria

platelets

• <1% of blood

• clots the blood

arteries

• Carry blood AWAY from the heart

• thick layer of muscle and elastic fibres for HIGH PRESSURE blood

• small lumen

capillaries

• Where DIFFUSION occurs

• wall is 1 cell thick for low diffusion distance and higher diffusion rate

• very small lumen so blood moves slowly so there is more time for diffusion

Veins

• carry blood TOWARDS heart

• has valves to prevent backflow of blood

• Large lumen

• thing layer of muscle (low pressure blood)

De-oxygenated blood travels trough…,

Vena Cava > Right atrium > Right Ventricle > Pulmonary Artery > Lungs

Oxygenated Blood

Lungs > Pulmonary Vein> Left atrium > left ventricle> aorta > whole body

what carries oxygenated blood from lungs to heart

pulmonary vein

what carries de-oxygenated blood from heart to lungs

Pulmonary artery

What carries oxygenated blood from heart to body

Aorta

what carries de-oxygenated blood from body to heart

Vena cava