Section 4 - Respiration and Gas Exchange Flashcards Preview

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Flashcards in Section 4 - Respiration and Gas Exchange Deck (14)
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How do plants exchange gases by diffusion (3)

- Plants photosynthesising use up CO2, so there's hardly any inside the leaf

- Meaning more CO2 diffuses into the leaf (area of high conc to low)

- At the same time, oxygen is being made as a waste product of photosyenthesis

- Some is used up in respiration, and the rest diffuses out through the stomata (area of high conc to low conc)


How are leaves adapted for efficent gas exchange (6)

- Leaves are broad, so there's a large surface area for diffusion

- Leaves are thin, meaning gases only have to travel a short distance to reach the cells where they're needed

- Air spaces: Let gases like carbon dioxide and oxygen move easily between cells, also increases surface area for gas exchange

- Stomata : Let gases like carbon dioxide and oxygen diffuse out, also allow water to transpire.

- Stomata close in the dark, so they don't let carbon dioxide in, and don't allow water to escape

- Opening and closing of the stomata is controlled by guard cells


Describe how a human breathes in (5)

- Intercostal muscles contract

- diaphragm contract

- Thorax volume increases

- Decrease in pressure

- draws air in


Describe how a human breathes out (4)

- Intercostal muscles and diaphragm relax

- Thorax volume decreases

- Pressure increases

- Air is forced out


Describe an investigation of the effect of exercise on breathing rate (5)

- Sit still for 5 minutes, then for one minute, count the number of breaths you take

- 4 munutes of running, stop, count breathes for a minute

- Get 3 other people to do the same (compare results)

- Excercise increases breathing rate

- Control : time spent exercising, temperature, same exercise type


Why does exercise increase your breathing rate (3)

- Muscles respire more during exercise

- They need to be supplied with more oxygen 

- And have more carbon dioxide removed


Explain how alveoli carry out gas exchange in the body (6)

- Lungs contain millions of little air sacs called alveoli, where gas exchange happens

- Blood passing next to the alveoli contains lots of carbon dioxide and little oxygen

- Oxygen diffuses out of the alveolus into the blood

- carbon dioxide diffuses out of the blood into the alvelous to be breathed out

- When the blood reaches body cells oxygen is released from red blood cells, and diffuses into body cells

- At the same time, carbon dioxide diffuses out of body cells, into blood, then carried back to the lungs


What does blood passing next to alveoli have (2)

- Small amounts of oxygen

- Large amounts of carbon dioxide


How are alveoli specialised for gas exchange (10)

- Millions of microscopic alveoli

-  give lungs an enormous surface area

- There's a moist lining

- for gases to dissolve in

- Thin walls, one cell thick,

- so gas doesn't have far to diffuse

- Great blood supply,

- to maintain a high conc gradient

- Permeable walls,

- so gases can diffuse across easily.


Explain how smocking tobacco can affect your lungs and circulatory system (5)

- Damages walls of the alveoli : reducing surface area for gas exchange, leading to diseases like emphysema.

- Tar in cigs damages the cilia in your lungs and trachea. Makes chest infections more likely

- Tar irritates the bronchi and bronchioles, mucus produced which cannot be ceared by damaged cilia - this causes smoker's cough and chronic bronchitis

- Carbon monoxide reduces amount of oxygen the blood can carry. Blood pressure increases, damaging artery walls, blood clots more likely.

- Carcinogens, which are chemicals that lead to cancer


What does smoking have/do that... (3)

a) Leads to cancer

b) Leads to smokers cough

c) Leads to emphaesyma

- Carcinagens

- irritates bronchi and bronchiolles

- Damages walls of the alveoli


Word equation for anerobic respiraton in 

Plants, Animals

Plants : glucose > ethanol + carbon dioxide (+energy)
Animals : glucose > lactic acid (+energy)


What is respiration (2)

- Process of releasing energy from glucose

- Which happens constantly in every living cell