1.2 Gas exchange and respiration (Diffusion)

• Biology
• Middelbare school
• vwo
• Leerjaar 2

0

Ch. 1 Breath in ... and out

Materials 

- iPad

- Pen, pencil

- note book

For a mark

- No

Lessonup

- Yes

Bags

in bag closet

Phones 

in your bag /

in bag closet 

today''s program 

results 2-test 

revision homework

diffusion

homework

Learning objectives: 'what I am going to learn?'

I can .... 

• explain what air is.
• explain the difference between breathing, gas exchange and cellular respiration 
• explain the relation between photosynthesis and cellular respiration

New key terms:

inhalation - exhalation - lung ventilation - gas exchange - 

cellular respiration 

previous lesson

Air is a mixture of gasses 

breathing = lung ventilation = inhalation + exhalation

so your body takes 4% oxygen and gets rid of 3,96% of CO2 and a lot of water ... why? Read a again the introduction of par. 1.1.

so 21- 17 = 4% O2 is used in the body

so 4-0,04=3,96% CO2 is waste from the body

a lot of water is exhaled!

Why?

breathing (a.k.a. respiration) vs gas exchange vs cellular respiration

1. breathing/respiration/lung ventilation: 

• inhalation & exhalation; moving air through the respiratory tract

2. gas exchange 

• exchange of gasses from alveoli (external)  to lung capillaries  (internal) and vice versa , or between capillary and body cell, by a process called diffusion

3. cellular respiration: 

• the process by which your cells make energy (and carbon dioxide and water vapour) from glucose, with the help of oxygen

cellular respiration:

glucose + 1 -> 2 + water vapour + E

1. 1=carbon dioxide 2= oxygen
2. 1= oxygen 2= carbon dioxide

When do your body cells respire the most?

1. when you run
2. when you've had your dinner
3. when you are asleep
4. when you just have woken up

when do your muscle cells respire the most?

1. playing basketball during PE hour
2. doing a practical during biology

You are shivering because the temperature in your room is 15C.
- how does your body react?

1. more cellular respiration
2. less cellular respiration

Learning objectives: 'what I am going to learn?'

I can .... 

• explain what diffusion is and give an example
• explain the difference between gas exchange and diffusion
• describe how gasses travel from the lungs to body cells 
• compare diffusion of gasses and diffusion of water (osmosis)

New key terms:

diffusion, osmosis 

how does gas exchange take place? 

mechanism : diffusion 

between  alveoli  and lung capillaries

between capillaries and body cells 

assignment

• read button F and G in Brick's Biology 
• copy the definition of DIFFUSION in your note book
• do exercises 2, 3 and 4
• read button H and copy the last sentence in your note book and fill in the gaps 

what makes gas exchange between alveoli and lung capillaries so effective? and between 'body' capillaries and body cells?

• a large amount of alveoli / body cells 

         --> large surface for diffusion

• a large amount of lung capillaries  / body capillaries

         --> large surface with difference is gas concentration 

• alveoli, capillaries and body cells  have thin 'walls' (=1 layer of cells) 

        --> short distance for diffusion 

what else makes diffusion
easier in the lungs?

homework

learn 1.2 diffusion (button A - G)

read about osmosis (button H and I)

finish exercises 1-4

next lesson pratical ...