Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology iGCSE > B8 - Gas exchange and Respiration > Flashcards

B8 - Gas exchange and Respiration Flashcards

1
Q

Respiration

A

An enzyme controlled chemical process that involves the breakdown of nutrient molecules (specifically glucose) in order to release the energy stored within the bonds of these molecules
* it occurs in all living cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Aerobic respiration

A

The chemical reactions in cells that use oxygen to break down nutrient molecules to release a large amount of energy
* most of the chemical reactions in aerobic respiration take place in the mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Anaerobic respiration

A

The chemical reactions in cells that break down nutrient molecules to release energy without using oxygen and release a relatively small amount of energy
* produces different breakdown products depending on the type of organism it is taking place in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What processes are carried out as a result of respiration? (name 5)

A
  • Muscle contraction
  • Protein synthesis
  • Cell division (to make new cells)
  • Growth
  • Active transport across cell membranes
  • Generation of nerve impulses
  • Maintaining a constant internal body temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Measuring the rate of respiration in yeast cells using methylene blue

A
  1. Add the dye to a suspension of yeast cells (doesn’t damage cells)
  2. The time taken for the methylene blue to discolour (lose its colour) is a measure of the rate of respiration of the yeast cells in the suspension - the faster the change the faster the respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is methylene blue a suitable indicator for measuring the rate of respiration in yeast?

A

If methylene blue stain is applied to a sample, a healthy cell with turn the stain colorless.
* This is due to the cell’s enzymes, which reduce the methylene blue, causing it to lose its color.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Apparatus needed for investigating the rate of respiration in yeast with a change in temperature

A
  • Yeast suspension
  • Glucose solution
  • Test tubes
  • Stopwatch
  • Methylene blue
  • Temperature-controlled water bath(s)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Independent variable

A

the variable that is changed on purpose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Dependent variable

A

the variable that is measured, i.e. the variable that depends on the independent variable for its outcome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Control variables

A

The variables that are kept the same in an experiment to ensure accurate results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the control variables when investigating the effects of temperature on the rate of respiration in yeast cells?

A
  • Volume/concentration of methylene blue added
  • Volume/concentration of yeast suspension
  • Concentration of glucose
  • pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the results of the experiment on the yeast?

A
  • As the temperature increases up to 40 °C, the rate of respiration increases so the time taken for the solution to become colourless reduces
    * this is because the enzymes will increase to optimum temperature where they work best * As temperature increases above 40 °C, the rate of respiration decreases so the time taken for the solution to become colourless increases
    * this is because the enzymes will start to denature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Suspension meaning

A

The state in which the particles of a substance are dispersed but not totally dissolved in a fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Word equation for aerobic respiration

A

glucose + oxygen -› carbon dioxide + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Balanced chemical equation for aerobic respiration

A

C(6)H(12)O(6) + 6O(2) -› 6CO(2) + 6H(2)O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain anaerobic respiration in animals

A

Takes place in muscle cells during vigorous exercise
* muscles have higher demand for oxygen than when resting and body can only produce so much using aerobic respiration
* as much glucose as possible is broken down with oxygen, and some glucose is broken down without it, producing lactic acid instead
* there is still energy stored within the bonds of lactic acid molecules that the cell could use; for this reason, less energy is released when glucose is broken down anaerobically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the uses of anaerobic respiration in yeast

A
  • Used during bread making where carbon dioxide is produced causing the bread to rise
  • Used in brewing (production of beer) where ethanol and carbon dioxide is produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Balanced equation for anaerobic respiration in yeast

A

C(6)H(12)O(6) -› 2C(2)H(5)OH + 2CO(2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Explain the process of repaying oxygen debt

A
  1. Lactic acid builds up in muscle cells and lowers the pH of the cells (making them more acidic)
  2. This could denature the enzymes in cells so it needs to be removed
  3. Cells excrete lactic acid into the blood
  4. When blood passes through the liver, lactic acid is taken up into liver cells where it is oxidised, producing carbon dioxide and water which are waste products (aerobic respiration of lactic acid)
  5. This is the reason we continue to breath heavily and our heart rate remains high even after finishing exercise
    • we need to transport the lactic acid from our muscles to the liver, and continue getting larger amounts of oxygen into the blood to oxidise the lactic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Features of gas exchange surfaces (4)

A
  • Large surface area: to allow faster diffusion of gases
  • Thin walls: for short distance
  • Good ventillation with air: so that the diffusion gradients can be maintained
  • Good blood supply: maintain high concentration gradent for faster diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Ribs

A

Bone structure that protects internal organs such as the lungs

22
Q

Intercostal muscle

A

Muscles between the ribs which control their movement causing inhalation and exhalation

23
Q

Diaphragm

A

Sheet of connective tissue and muscle at the bottom of the thorax (area between the neck and abdomen) that helps change the volume of the thorax to allow inhalation and exhalation

24
Q

Trachea

A

Windpipe that connects the mouth and nose to the lungs

25
Q

Larynx

A

Also known as the voice box, when air passes across here we are able to make sounds

26
Q

Bronchi

A

Large tubes branching off the trachea with one bronchus for each lung

27
Q

Bronchioles

A

Bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli

28
Q

Alveoli

A

Tiny air sacs where gas exchange takes place

29
Q

Experiment for the difference in inspired and expired air

A
  1. When we breathe in, the air is drawn through boiling tube A
  2. When we breathe out, the air is blown into boiling tube B
  3. Lime water is clear but becomes cloudy (or milky) when carbon dioxide is bubbled through it
  4. The lime water in boiling tube A will remain clear, but the limewater in boiling tube B will become cloudy
  5. This shows us that the percentage of carbon dioxide in exhaled air is higher than in inhaled air
30
Q

Contents of air

A
  • 20-21% oxygen
  • 0.04% carbon dioxide
  • 78% nitrogen
  • 0.93% argon
  • smaller amounts of other gases
31
Q

Inspired air

A

The air that is taken inside the body through the nostrils during inhalation

32
Q

Expired air

A

The air that is given out from the lungs during the process of exhalation

33
Q

Oxygen in air (inspired and expired and reason)

A
  • 21% in atmosphere
  • 4-5% absorbed
  • 16% exhaled
  • Oxygen is removed from blood by respiring cells so blood back to lungs has lower oxygen concentration
34
Q

Carbon dioxide in air (inspired, expired and reason)

A
  • 0.04% in air/inspired
  • 4% expired
  • Produced by respiration and diffuses into blood from cells; transported to the lungs; diffuses into alveoli and into air
35
Q

Difference in inspired and expired air water vapour and temperature

A

The air we breathe out contains more water vapour than when we breathe it in, and the temperature of exhaled air is higher than inhaled air
* water evaporates from the moist lining of the alveoli into the expired air as a result of the warmth of the body

36
Q

Nitrogen (inspired and expired and reason)

A
  • 78% inspired
  • 78% expired
  • It is very stable and so cannot be used by the body, so it is not absorbed
37
Q

Investigation for the effects of physical activity on breathing (4 steps)

A
  1. This can be investigated by counting the breaths taken during one minute at rest and measuring average chest expansion over 5 breaths using a tape measure held around the chest
  2. Exercise for a set time (at least 3 minutes)
  3. Immediately after exercising, count the breaths taken in one minute and measure the average chest expansion over 5 breaths
  4. Following exercise, the number of breaths per minute will have increased and the chest expansion will also have increased
38
Q

How does exercise affect breathing

A

Exercise increases the frequency and depth of breathing

39
Q

Cartilage (definition and function)

A

Rings of cartilage surround the trachea (and bronchi)
* to support the airways and keep them open during breathing
* if they were not present the sides could collapse inward when their pressure drops

40
Q

Describe the process of breathing in (6 steps)

A
  • External intercostal muscles contract
  • Ribcage moves up and out
  • Diaphragm contracts and flattens
  • Volume of thorax increases
  • Pressure inside thorax decreases
  • Air is drawn in
41
Q

Describe the process of breathing out

A
  • External intercostal muscles relax
  • Ribcage moves down and in
  • Diaphragm relaxes and becomes dome-shaped
  • Volume of thorax decreases
  • Pressure inside thorax increases
  • Air is forced out
42
Q

Why does excercise increase frequency and depth of breathing? (mention aerobic and anaerobic respiration, lactic acid and oxygen debt)

A
  • Because muscles work harder and aerobically respiring more and so need more oxygen delivered to them
  • If the energy demand is not met they will also respire anaerobically, producing lactic acid
  • After exercise, the lactic acid built up in muscles needs to be removed as it lowers the pH of cells and can denature enzymes
  • It is removed by combining it with oxgen - process called ‘repaying oxygen debt’
43
Q

How is the amount of lactic acid produced from anaerobic respiration tested?

A

Seeing how long it takes after exercise for the breathing rate and depth to return to normal
* the longer it takes, the more lactic acid was produced and the greater the oxygen debt was

44
Q

What mechanisms interact in the body during heavy exercise?

A
  • CO2 is produced from aerobic respiration and these levels increase in muscle cells
    • this diffuses out of the cells into the blood plasma (slight drop in pH causes blood to be more acidic)
  • Blood flows around circulatory system and passes to the brain where the increased CO2 levels are detected by chemoreceptors
  • Brain sends nerve impulses to diaphragm and intercostal muscles to increase the rate and depth of muscle contraction
  • Rate of respiration increases and volume of air inspired does too
  • Results in greater absorption of oxygen and removal of CO2
45
Q

Chemoreceptors

A

Chemoreceptors are cells that detect chemical changes in the body
* they detect changes in blood gas levels and changes in pH
* located in medulla oblongata in brain

46
Q

Function of ciliated epithelial cells

A

The passages down to the lungs are lined with ciliated epithelial cells which have tiny hairs at the end of them
* these beat and push mucus up the trachea towards the nose and throat where it can be removed

47
Q

Function of mucus in throat

A

Made by special mucus-producing cells called goblet cells
* mucus traps particles, pathogens like bacteria or viruses and dust and prevents them from getting into the lungs and damaging cells

48
Q

Components of tobacco smoke

A
  • Tar
  • Nicotine
  • Carbon monoxide
  • Smoke particles
49
Q

How does tar affect the gas exchange system?

A

Tar is a carcinogen which increases the risk of cancer
* It is deposited along the airways
* Irritates goblet cells causing them to produce too much mucus and damages/paralyses celiated epithelial cells
* Mucus builds up and blocks the airways
* This can lead to chronic bronchitis

50
Q

How does nicotine affect the gas exchange system?

A

Nicotine is an addictive substance
* It increases heart rate and blood pressure

51
Q

How does carbon monoxide affect the gas exchange system?

A

Carbon monoxide is a toxic gas
* It combines premanently with haemoglobin
* Prevents it from binding to and transporting oxygen

52
Q

How do smoke particles affect the gas exchange system?

A
  • Smoke particles irritate the air passages
  • Increases mucus production
  • Causes the airways to inflame and possibly result in blockages
    • can lead to chronic bronchitis
  • Their presence in alveoli may lead to emphysema - the breaking of alveoli walls
  • They can cause heavy coughing - the body’s attempt to expel them

Biology iGCSE (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions