Chapter 8 - Respiration Flashcards

(67 cards)

1
Q

What is respiration?

A

A process liberating chemical energy from the oxidation of organic molecules

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2
Q

Why do living organisms respire?

A

They need energy to sustain life; to move, grow,

excrete and reproduce

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3
Q

How do living organisms obtain energy?

A

Obtained through the consumption of food

- To use the energy available in food, living things break down the food molecules through oxidation

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4
Q

What is aerobic respiration?

A

The release of a relatively large amount of energy by the breakdown of food substances in the presence of oxygen

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5
Q

What is produced in aerobic respiration?

A
  • A large amount of energy

- Carbon dioxide and water as waste products

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6
Q

What is the chemical equation for aerobic respiration?

A

C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

glucose + oxygen → carbon dioxide + water + energy

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7
Q

What is ATP?

A

Adenosine triphosphate: A small molecule in which energy released during respiration is stored
- The main energy currency used in all living cells

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8
Q

How is energy released from the ATP?

A
  • A phosphate bond is broken

- Adenosine triphosphate (ATP) is converted to adenosine diphosphate (ADP)

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9
Q

How is energy stored in the ATP?

A
  • A phosphate bond is formed

- Adenosine diphosphate (ADP) is converted to adenosine triphosphate (ATP)

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10
Q

Advantages of the ATP

A
  • Soluble: can move around freely in the cell to provide energy wherever it is required (mobile)
  • Reversible
  • Small
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11
Q

What are the stages of aerobic respiration and where do they occur?

A
  1. Glycolysis (in the cytoplasm of the cell)
  2. Krebs cycle (in the matrix of mitochondria)
  3. Electron Transport Chain and Oxidative Phosphorylation (on membrane of mitochondria)
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12
Q

How many ATP molecules does glycolysis produce?

A

2

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13
Q

How many ATP molecules does Krebs cycle produce?

A

2

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14
Q

How many ATP molecules does electron transport chain and oxidative phosphorylation produce?

A

26 or 28

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15
Q

Where does aerobic respiration occur?

A

In the mitochondria of all cells

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16
Q

Oxidation of carbohydrates

A

Many carbohydrates enter glycolysis after conversion to glucose

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17
Q

During starvation, which food molecule will first be oxidised to release energy?

A
  1. Carbohydrate
  2. Fats
  3. Proteins
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18
Q

Oxidation of amino acids, fatty acids and glycerol

A

Amino acids, fatty acids and glycerol can enter glycolysis and Krebs cycle at various points

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19
Q

What is anaerobic respiration?

A

The release of a relatively small amount of energy by the breakdown of food substances in the absence of oxygen

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20
Q

How does anaerobic respiration occur?

A

Occurs through glycolysis, followed by lactate fermentation or alcoholic fermentation

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21
Q

Anaerobic respiration releases ________ energy than aerobic respiration

A

less

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22
Q

What is the chemical equation for anaerobic respiration (in humans)?

A

C6H12O6 → 2C3H6O3 + energy

glucose → lactic acid + energy

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23
Q

What are the 2 kinds of anaerobic respiration in where do they occur?

A
  1. Alcoholic fermentation (in yeasts and plants)

2. Lactate fermentation (in muscles of animals)

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24
Q

What is the word equation for alcoholic fermentation in yeast?

A

glucose → alcohol + carbon dioxide + small amount of energy

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25
What is the word equation for lactate fermentation in muscle cells?
glucose → lactic acid + small amount of energy
26
What happens during exercise?
- Muscles contract vigorously to enable movement - Respiratory rate and heart rate increase to enable more oxygen to reach the muscles - If the increased oxygen intake is not able to meet the oxygen demand, an oxygen debt results and anaerobic respiration takes place to provide the energy required - Anaerobic respiration results in the accumulation of lactic acid in the muscle cells - Lactic acid accumulation can cause fatigue and muscular pains
27
What happens during the period of rest?
- Breathing rate continues to be fast to provide sufficient oxygen to repay the oxygen debt - Lactic acid is removed from the muscles and transported to the liver where it is oxidised to produce energy or converted to glucose - Glucose will be transported back to the muscle
28
Experiment: Carbon dioxide is a product of respiration (1)
The potassium hydroxide in flask A removes carbon dioxide from the air entering flask B. • The limewater in flask B should not have white precipitate forming. • The air entering flask C does not contain carbon dioxide. Hence, any carbon dioxide detected in flask D would be due to respiration by the snails.
29
Experiment: Carbon dioxide is a product of respiration (2)
- The glucose solution that is used was first boiled and cooled to remove the dissolved oxygen from the solution - Due to the limited oxygen available to the yeast, the yeast undergoes anaerobic respiration - If carbon dioxide is released during the anaerobic respiration of yeast, white precipitate will form in limewater
30
Experiment: Heat is a product of respiration
- The vacuum flask prevents heat from escaping and entering the area where the seeds are germinating - The cotton wool plug allows gaseous exchange between the seeds and the environment - The antiseptic solution prevents the growth of microorganisms like bacteria - If heat is produced during respiration, the thermometer would register a temperature higher than the surrounding temperature
31
Why is there a need for a respiratory system in humans?
- Humans are large organisms that are made up of millions of cells - We have a small surface area to volume ratio, unlike unicellular microorganisms - Therefore, we need a special system of organs for gaseous exchange between the environment and the cells in our bodies
32
Features of the nasal passage and their functions
The fringe of hair and the mucous layer (on the walls of the nasal passage): trap dust and foreign particles
33
As the air passes through the air passages, it is ________
warmed and moistened
34
Feature of the trachea and its function
Supported by C-shaped rings of cartilage: ensure that the trachea is always open
35
Features of inner walls of trachea and bronchi and their functions
- Gland cells: secrete mucus that trap dust particles and bacteria in the air that is channelled to the lungs - Ciliated cells have cilia that sweep the trapped particles and bacteria up the bronchi and trachea, into the pharynx
36
The lungs lie in the ________ cavity
pleural
37
Within the lungs, the ________ tubes divide repeatedly to form ________
bronchial | bronchioles
38
Bronchioles end in cluster of ________
alveoli
39
What are alveoli?
Air sacs in the lungs which form the site of gaseous exchange
40
Features of alveoli and their functions
Numerous: increases the surface area to volume ratio for efficient gaseous exchange Well-supplied with blood capillaries: enables the efficient exchange of gases Alveolar surface is coated with a thin film of water: allows gases to dissolve in it Wall of each alveolus is only one cell thick Supplied by capillaries that are also only one cell thick
41
How is oxygen transported?
Oxygen molecules bind to haemoglobin (Hb) in red blood cells to form oxyhaemoglobin
42
Equation for binding of oxygen by haemoglobin
Hb + 4O2 → Hb(O2)4
43
How carbon dioxide is transported?
1. Carbon dioxide molecules from respiring cells enter the red blood cells in the blood stream 2. React with water to form carbonic acid (catalysed by carbonic anhydrase in the red blood cells) 3. Converted into hydrogen carbonate ions (HCO3-) which will diffuse out of the red blood cells and into the blood plasma
44
Function of ribs
Support the chest wall
45
What are the two sets of muscles found between the ribs?
1. External intercostal muscles | 2. Internal intercostal muscles
46
Function of intercostal muscles
To move the rib cage up and down during breathing
47
What is the diaphragm?
A dome-shaped sheet of muscle and elastic tissue
48
Function of the diaphragm
Contracts and relaxes to change the volume of the thoracic cavity
49
Inspiration (1)
Diaphragm contracts and flattens down
50
Inspiration (2)
External intercostal muscles contract and internal intercostal muscles relax → rib cage is raised upwards and outwards
51
Inspiration (3)
Thoracic volume increases, so air is drawn into the lungs
52
Expiration (1)
Diaphragm relaxes and arches upwards
53
Expiration (2)
External intercostal muscles relax and internal intercostal muscles contract → rib cage moves downwards and inwards
54
Expiration (3)
Thoracic volume decreases, lungs are compressed and air is forced out of the lungs
55
Properties of nicotine
- Addictive - Causes the release of the hormone adrenaline - Makes blood clot easily
56
Effects of nicotine on the body
- Increase heartbeat rate and blood pressure | - Increases risk of blood clots in the arteries → increased risk of coronary heart disease
57
Effects of carbon monoxide on the body
- Reduces the ability of red blood cells to transport oxygen - Narrows the lumen of arteries and leads to increase in blood pressure
57
Properties of carbon monoxide
- Combines with haemoglobin to form carboxyhaemoglobin | - Increases the rate of fatty deposits on the inner arterial wall → increased risk of coronary heart disease
58
Properties of tar
- Causes uncontrolled cell division | - Paralyses cilia lining the air passages
59
Properties of irritants
- Paralyse cilia lining the air passages
60
Effects of tar on the body
- Carcinogenic - Dust particles trapped in the mucus lining the air passages cannot be removed → increases risk of chronic bronchitis and emphysema
61
Effects of irritants on the body
- Dust particles trapped in the mucus lining the air passages cannot be removed → increases risk of chronic bronchitis and emphysema
63
Examples of irritants
- formaldehyde | - hydrogen cyanide
64
What happens in chronic bronchitis?
- The epithelium lining the airways is inflamed - There is excessive mucus secretion - The cilia lining the airways are paralysed
65
What are the symptoms of chronic bronchitis?
- Breathing difficulties due to blocked airways | - Persistent cough (body’s response to clear the blocked airways)
66
What happens in emphysema?
- The partition walls of alveoli break down due to violent coughs → reduces the surface area available for gaseous exchange - The lungs lose their elasticity and become inflated with air
67
What are the symptoms of emphysema?
- Breathing difficulties | - Wheezing