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2 Respiration + Gas Exchange Flashcards

1
Q

What is respiration?

A

the process of transferring energy from glucose, which happens constantly in every living cell

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2
Q

How is energy transferred by respiration?

A

Used to make ATP which stores the energy needed for many cell processes

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3
Q

What is ATP?

A

adenosine triphosphate, releases energy quickly

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4
Q

How is ATP used?

A

ATP molecules are broken down and energy is released.

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5
Q

What is the word and chemical equation for aerobic respiration?

A

glucose + oxygen -> carbon dioxide + water ( + energy)
C₆H₁₂O₆ + 6O₂ -> 6CO₂ + 6H₂O

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6
Q

How many molecules of ATP are produced during aerobic respiration?

A

32 molecules per molecule of glucose
(most efficient way to transfer energy from glucose)

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7
Q

What is the word equation for anaerobic respiration in animals?

A

glucose -> lactic acid (+energy)

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8
Q

Why do we anaerobically respire?

A

doing vigorous exercise means your body can’t supply enough oxygen to working muscles for aerobic respiration. Instead muscles respire without oxygen

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9
Q

How many molecules of ATP are produced during anaerobic respiration?

A

2 molecules per glucose molecule

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10
Q

What happens when lactic acid is produced?

A

glucose is only partially broken down and lactic acid is produced which builds up in muscles - painful and leads to cramp

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11
Q

How is lactic acid removed?

A

by blood flowing through muscles

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12
Q

What is the word equation for anaerobic respiration in plants?

A

glucose -> ethanol + carbon dioxide (+ energy)

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13
Q

What are the differences between aerobic and anaerobic respiration?

A

aerobic = with oxygen, releases more energy but slowly
anaerobic = without oxygen, releases less energy but quicker

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14
Q

PAPER 2 What is the role of diffusion in gas exchange in a leaf?

A

carbon dioxide diffuses into leaf through stomata while oxygen diffuses out of leaf through stomata

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15
Q

PAPER 2 How are leaves adapted for gas exchange?

A

Leaves are broad - large SA for diffusion, increasing number of stomata, carbon dioxide diffuses quicker
Stomata allow gases to diffuse in and out of air spaces of leaf, provides short diffusion to mesophyll cells
Guard cells change shape to alter size of stomata
Thin - gases travel a short distance
Air spaces inside leaf - lets gases move easily between cells. Increases SA for gas exchange
Stomata close to reduce water loss and gas exchange

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16
Q

PAPER 2 What is the role of the stomata in gas exchange?

A

Stomata close as it gets dark. Photosynthesis cant happen in dark, so don’t need to be open to let in CO₂
water can’t escape when closed, stops plant drying out
Opening and closing is controlled by guard cells. do this by changing their shape and volume (increase in volume to open up, decrease to close)

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17
Q

PAPER 2 Why is photosynthesis faster than respiration during the day?

A

higher light intensities - net uptake of carbon dioxide and net release of oxygen. Oxygen secreted from leaves

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18
Q

PAPER 2 Why is respiration faster than photosynthesis during the night?

A

low light intensities - net uptake of oxygen and net release of carbon dioxide. Carbon dioxide is secreted from leaves

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19
Q

PAPER 2 What does it mean if photosynthesis is faster than respiration?

A

oxygen is excreted from leaves

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20
Q

PAPER 2 What does it mean if respiration is faster than photosynthesis?

A

carbon dioxide is excreted from leaves

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21
Q

PAPER 2 What does it mean if photosynthesis and respiration occur at the same rate?

A

no net gas exchange

22
Q

PAPER 2 Describe the investigation of how light affects gas exchange from a leaf?

A

Privet leaves placed in 3 boiling tubes containing 2cm³ of sodium hydrogen carbonate indicator (red/orange)
One tube in bright light, one wrapped in foil, one wrapped in tissue paper (weak light)
Place a dead privet leaf in test tube in bright light
Tubes left for 40 mins

23
Q

PAPER 2 What are the expected results of the investigation on how light effects leaves?

A

Leaf with aluminium cover: yellow,
respiration > photosynthesis
CO₂ > O₂
Leaf with tissue: red,
respiration = photosynthesis
Leaf with no cover: purple,
respiration < photosynthesis
CO₂ < O₂
Dead leaf: red,
no living cells

24
Q

Describe the structure of the thorax

A

Trachea
Bronchi
Bronchioles
Rib
Intercostal muscles
alveoli
diaphragm
pleural membrane

25
Describe the trachea
When we breathe, air passes down Surrounded by c-shaped cartilage Keeps trachea open and makes swallowing easier
26
Describe the bronchi
Lead to lungs Also surrounded by cartilage rings
27
Describe the bronchioles
carry air deep into thorax
28
What happens at the alveoli?
microscopic air sacs site of gas exchange
29
what are the lungs surrounded by?
pleural membrane
30
What is the pleural membrane?
forms a double layer between lungs and thorax walls. Thin layer between membranes of pleural fluid. Together form air tight seal and prevent lungs from sticking to thorax wall as they inflate and deflate
31
What do the ribs do?
Help protect organs in thorax
32
What do the intercostal muscles do?
between ribs help to connect bones and important in moving air into and out of lungs
33
Describe the diaphragm
Separates organs of thorax and abdomen domed sheet of muscle and fibrous tissue important in moving air into and out of lungs
34
What is ventilation?
the process of moving air into and out of the lungs moving air relies on differences in air pressure between lungs and atmosphere
35
What happens to the thorax during inhalation?
diaphragm contracts, moving down and flattening. Intercostal muscles contract, moving rib cage up and out Causes volume of thorax to increase and air pressure to decrease causes air to move into lungs as air pressure in thorax is less than atmospheric pressure
36
What happens to the thorax during exhalation?
Diaphragm relaxes, moving up and doming Intercostal muscles relax, moving rib cage down and in causes volume to decrease and air pressure increase air pressure more than atmospheric pressure so air moves out of lungs
37
How do oxygen and carbon dioxide diffuse in and out of the alveoli?
oxygen diffuses into red blood cells and binds to haemoglobin for transport carbon dioxide, dissolved in plasma, diffuses from blood into alveolus
38
How are alveoli adapated for gas exchange?
large surface area - lots of alveoli increases rate capillaries - surrounded by network, which constantly carry deoxygenated blood to alveolus and move oxygenated blood away - maintains high concentration gradient short distance - walls one (flattened) cell thick
39
Describe an investigation that compares the content of inhaled and exhaled air
T-tube arrangement going from mouthpiece to two boiling tubes student breathes in and out limewater: inhaled = stays colourless exhaled = turns milky white
40
How do you investigate the effect of exercise on breathing?
Counting number of breaths someone takes in 1 minute at rest then exercise e.g. jog on spot for 5 minutes count number of breaths taken in first min after exercise valid conclusion = investigate lots of people Control variables: age, gender, fitness, type of exercise, length of exercise
41
Why does breathing rate increase during exercise?
breathing and depth increases in response to increase in concentration of carbon dioxide in blood
42
What happens as breathing rate increases?
We excrete carbon dioxide more rapidly. Oxygen diffuses into blood faster rate Increase heart rate All supplies more oxygen to muscles for aerobic respiration
43
What happens if we anaerobically respire during exercise?
breathing rate remains high to supply extra oxygen to oxidise lactic acid
44
What is the highly addictive drug present in tobacco smoke?
Nicotine - many treatments contain nicotine to gradually reduce intake without exposure to other harmful chemicals
45
What are carcinogens?
chemicals in tobacco smoke which can alter DNA and increase risk of cancer
46
What is an example of a carcinogen?
tar
47
What does carbon monoxide do?
found in tobacco smoke irreversibly binds to haemoglobin, forming carboxyhaemoglobin, reducing amount of oxygen transported by blood
48
What happens if a pregnant women smokes?
baby will receive less oxygen, resulting in weighing less at birth which can lead to other problems
49
How are healthy lungs specialised to prevent dirt and bacteria entering lungs?
Goblet cells produce mucus, which traps dust and pathogens Cilia on lining of cells move, transporting mucus up airways
50
How do the lining of trachea and bronchi change from tobacco smoke?
chemicals destroy cili, reducing their number Mucus production increases in response to smoke mucus cannot be removed out of airways and quickly builds up causes smokers cough and increases risk of infection
51
What is Bronchitis
the disease resulting from build-up of infected mucus in bronchi and bronchioles?
52
How does smoke affect the alveoli?h
alveoli walls break down in places and fuse together, forming larger irregular air spaces. Decreases surface area for gas exchange, so less oxygen diffuses into blood Disease called emphysema

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