4 - Respiration and Gas Exchange Flashcards Preview

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Flashcards in 4 - Respiration and Gas Exchange Deck (23)
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1

What is respiration?

The process of releasing energy from glucose which happens constantly in every living cell
Energy is released as chemical energy and heat

2

What is aerobic respiration?

Respiration when there is oxygen available
Glucose + oxygen ---> carbon dioxide + water (+ energy)
C6H12O6 + 6O2 ---> 6CO2 + 6H2O

3

What is anaerobic respiration?

Respiration without oxygen
Not the best way to respire as not as much energy is made
Happens during vigorous exercise
Glucose ---> lactic acid (+ energy)
The lactic acid can lead to muscle cramps in the body

4

What is anaerobic respiration in plants?

When plants respire without oxygen
Glucose ---> ethanol + carbon dioxide (+ energy)

5

Describe an experiment to detect the carbon dioxide produced in respiration

- Soak dried beans in water for a day so they begin to germinate (they will respire)
- Boil a similar sized second batch of dried beans
- This kills the beans so they cannot respire (the control)
- Put hydrogen-carbonate indicator into two test tubes
- Place a gauze platform into each test tube to put the beans on
- Seal with a rubber bung
- Leave for an hour
-The CO2 produced will then the indicator from orange to yellow

6

Describe an experiment to show the heat produced by respiration

- Prepare two sets of beans (one dried and one boiled)
- Add each set to a vacuum flask with a little air at the too (so they respire anaerobically)
- Put a thermometer into each flask and deal with cotton wool
- Record the temperatures daily for a week
- The beans are well-insulated in the flasks so when the germinating seeds respire the flask's temperature will Rose

7

How do plants exchange gas?

By diffusion from the environment into the leaf

8

What does the net exchange of has depend on?

Light intensity
- Plants photosynthesise in light so diffuse CO2 and O2 in and out constantly
- At night there is no photosynthesis so the plant does not release oxygen (it is only taken in) and release only carbon dioxide

9

How are leaves adapted for gas exchange?

- Broad so large surface area for diffusion
- Thin so less distance to travel
- Air spaces to let CO2 and O2 move easily between cells as well as increasing the surface area for has exchange
- Stomata allow CO2 and O2 diffuse in and out and let's water escape
- Stomata close at dark so no water is lost
- Stomata will close when there is little water left in the roots (stops the plant from photosynthesising but keeps it alive)
- The opening and closing of stomata are controlled by the guard cells

10

What does hydrogen-carbonate show?

- Carbon dioxide concentration
- Orange = normal concentration
- Yellow = increased concentration
- Purple = decreased concentration

11

Describe an experiment to show the difference in net gas exchange in plants

- Add the same volume of hydrogen-carbonate indicator to four boiling tubes
- Put similar leaves into three tubes and seal with a rubber bung (to stop it falling into the solution)
- Wrap one tube in aluminium foil and a second in gauze
- Put all the tubes in bright light
- Leave for an hour
- Tin foil = yellow as respiration took place but no photosynthesis
- Gauze = orange little photosynthesis and little respiration
- Uncovered = purple as lots of photosynthesis using carbon dioxide up

12

What is the thorax?

The top part of the body separated from the lower part by the diaphragm

13

Lungs

- Pink like sponges
- Protected by the ribcage
- Surrounded by the pleural membranes

14

Bronchi

- Air breathed in goes through the trachea to the two tubes of bronchi
- Bronchi split into bronchioles
- Bronchioles end at alveoli where gas exchange takes place

15

Where does gas exchange take place in humans?

The alveoli

16

Describe breathing in

- Intercostal muscles and diaphragm contract
- Thorax volume increases
- This decreases pressure an draws air in

17

Describe breathing out

- Intercostal muscles and diaphragm relax
- Thorax volume decreases
- Air is forced out

18

Describe an experiment to investigate the effect of exercise on breathing rate

- Sit still for five mins then count number of breaths in 1 min
- Do four mins of exercise and count breaths for 1 min
- Repeat with two other people
- Temperature may have an effect on the experiment
- Muscles respire dying exercise and need more oxygen so more breathing

19

How is gas exchange carried out in the body?

- The lungs contain millions of air sacs called alveoli
- Blood passing next to alveoli has lots of carbon dioxide and little oxygen
- Oxygen diffuses out of alveoli into blood
- Carbon dioxide diffuses into alveoli to be breathed out
- Oxygen is released from the red blood cells into the body cells
-

20

How are alveoli specialised for gas exchange?

- Millions of them so large surface area
- Moist lining for gases to dissolve in
- Thin walls (one cell thick) so not far to diffuse
- Good blood supply to maintain a high concentration gradient
- Permeable walls

21

Why is a good blood supply good in diffusion?

Maintains a high concentration gradient

22

What are the effects of smoking tobacco?

- Damages walls inside the alveoli, reducing surface area and can less to emphysema
- Tar damages cilia (hairs) in the lungs and trachea making chest infections likely
- Tar irritates the bronchi and bronchioles by encouraging mucus to be produced causing smokers cough and chronic bronchitis
- Carbon monoxide reduces the amount of oxygen the blood can carry increasing heart rate and blood pressure which damages artery walls and leads to blood clots and heart attacks
- Tobacco contains carcinogens which lead to cancer
-

23

What does cilia do?

Catch dust and bacteria before they reach the lungs and keep the trachea clear by sweeping mucus towards the mouth