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IGCSE Biology > Chapter 11:respiration and gas exchange > Flashcards

Chapter 11:respiration and gas exchange Flashcards

1
Q

what do every living cells need?

A

Energy

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2
Q

Why do we need energy (name 7 reasons)

A

-contracting muscles
-protein synthesis
-cell division
-active transport
-growth
-transmitting nerve impulses
-producing heat inside the body

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3
Q

Why do we need energy in contracting muscles?

A

So that we can move parts of the body

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4
Q

Why do we need energy in protein synthesis?

A

To link together amino acids into long chains

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5
Q

Why do we need energy in cell division?

A

So that we can repair damaged tissues and can grow

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6
Q

Why do we need energy in active transport?

A

So that we can move substances across cell membranes up their concentration gradients

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7
Q

Why do we need energy in growth

A

To build new cells which can be divided to form new cells

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8
Q

Why do we need energy in transmitting nerve impulses

A

So that we can transfer information quickly from one part of the body to another

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9
Q

Why do we need energy in producing heat inside the body?

A

To keep the body temperature constant even if the environment is cold

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10
Q

What is the main nutrient used to provide energy?

A

Glucose

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11
Q

Definition for aerobic respiration

A

Chemical reactions in cells that use oxygen to breakdown nutrient molecules to real ease energy

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12
Q

Where does aerobic respiration take place?

A

Mitochondria

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13
Q

Equation for aerobic respiration

A

Glucose + oxygen —>carbon dioxide +water

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14
Q

What is the balanced equation for aerobic respiration

A

C^6H^12^O6 + 6O^2 —> 6CO^2 + 6H^2O

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15
Q

Definition of anaerobic respiration

A

Chemical reactions in cells that breakdown nutrient molecules to realise energy without using oxygen

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16
Q

Where does anaerobic respiration take place in?

A

Cytoplasm

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17
Q

Which respiration release the most energy?

A

Anaerobic respiration releases much less energy per glucose molecules than aerobic respiration

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18
Q

Does yeast respire by aerobic respiration or anaerobic respiration

A

Anaerobically

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19
Q

What does yeast breakdown

A

It breaks down glucose to alcohol

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20
Q

Equation for breakdown of glucose to alcohol

A

Glucose —> alcohol + carbon dioxide

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21
Q

Chemical equation for breakdown of glucose to alcohol

A

C^6H^12^O^6 —> 2C^2H^5OH + 2CO^2

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22
Q

Name two which respire anaerobically with help of carbon dioxide

A

-plants
-muscle cells

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23
Q

What happens when you do to much exercise?

A

The muscle cells make lactic acid,the muscle cells release some energy from glucose without using oxygen,just to keep them going until oxygen is available again

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24
Q

Muscle cell equation

A

Glucose —> lactic acid

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25
When is lactic acid produced?
Lactic acid is built up in muscles and blood during vigorous exercise causing an oxygen debt
26
What is gas exchange
The diffusion of oxygen and carbon dioxide into and out of an organisms body
27
What is gas exchange surface?
A part of the body where gas exchange between the body and the environment takes place
28
Why is the gas exchange surface thin?
They are thin to allow gases to diffuse across them quickly
29
Why is the gas exchange surface close to efficient transport system?
They are close to an efficient transport system to take gases to and from the gas exchange surface
30
Why do gas exchange surface have a large surface area?
They have a large surface area so that a lot of gas can diffuse across at the same time
31
Name 4 features of gas exchange surface in humans
-large surface area -thin surface -good supply of oxygen -efficient transport system
32
Definition of trachea
The tube through which air travels to the lungs,it has rings of cartilage in its walls,to support it
33
Definition of alveoli
Tiny air-filled sacs in the lungs where gas exchange takes place
34
Where does air enter the body
Through the: -mouth -nose
35
What is the nose inside the nose?
Some thins bones,p which are covered with cells called Goblet cells
36
Where is goblet cells found?
In the lining of the respiratory passages and digestive system which secrets mucus
37
Definition of cilia
Tiny projections from of the cells in the living of the respiratory passages
38
Function of cilia
The cilia’s are always moving,and bacteria or particles of dust get trapped in them and in mucus. They sweep the mucus containing bacteria and dust particles up back to the throat,so that it does not block the lungs
39
Where is cilia found
-Trachea -bronchi
40
What contains the vocal cords
The larynx
41
State the function of cartilage in the trachea
As we breath in and out,the pressure of the air in the trachea increases and decreases so the cartilage helps to prevent the trachea collapsing at times when the air pressure inside is lower than the air pressure outside
42
Definition of bronchus
One of the two tubes that takes air from the trachea into the lungs
43
Definition of bronchiole
A small tube that takes air from a bronchus to every part of the lungs
44
Where does gas exchange take place
Alveoli
45
How is alveoli an excellent transport system
Because blood is constantly pumped to the lungs along the pulmonary artery.this branches into thousands of capillaries which take blood to all parts of the lungs.carbon dioxide in the blood can diffuse out into the blood.the blood is then taken back to the heart int he pulmonary vein,ready to be pumped to the rest of the body.
46
What is the surface area of alveoli in the lungs
100 m^2
47
Definition of ventilation
The movement of air into and out of the lungs,by breathing movements
48
What is the percentage of oxygen in inspired air
21%
49
What is the percentage of carbon dioxide in inspired air
0.04%
50
What is the percentage of oxygen in expired air
16%
51
What is the percentage of carbon dioxide in expired air
4%
52
What is the composition of water vapour in inspired air
Variable
53
What is the composition of water vapour in expired air
Usually very high
54
Why is there less oxygen when we breath out?
Because cells in the body use oxygen in respiration.
55
How does expired air have a significant amount of oxygen
Because the expired air mixes with normal air in the bronchi and trachea,so that we actually breath out a mixture of the air in the alveoli and atmospheric air
56
Why does the air we breath in contain only a very small percentage of carbon dioxide
Because body cells produce carbon dioxide in aerobic respiration and this carbon dioxide diffuses out of the blood and into the alveoli.
57
Definition of breathing
Using the muscles in the diaphragm and the inter coastal muscles,to change the volume of the thorax so that the air is drawn into and pushed out of the lungs
58
What is intercostal muscles
Muscles between the ribs,which raise and lower the rib cage when they contract and relax
59
What is diaphragm
A muscle that separates the chest cavity from the abdominal cavity in mammals;it helps breathing. -it is a large sheet of muscle and elastic tissues which stretches across the body,underneath the lungs and heart
60
How does inspiration take place
1-the muscles of the diaphragm contract 2-this pulls the diaphragm downwards,increasing the volume of the thorax 3-while this happens,the external intercostal muscles contract 4-this pulls the rib cage upwards and downwards;which increases the volume of the thorax 5-as the volume of thorax increases,the pressure inside it falls below the atmospheric pressure 6-therefore air flows in along the trachea and bronchi into the lungs
61
How does expiration happen
1-the muscles of the diaphragm relaxes 2-this makes the diaphragm spring back up into its domed shape because it is made of elastic tissues;this decreases the volume in the thorax 3-while this happens,the external intercostal muscles relax 4-this makes the rib cage drop down again to its normal position;which decreases the volume of the thorax 5-sometimes when you breath out for forcefully,the internal inter coastal muscles contract strongly,making the rib cage drop down even further 6-the abdomen wall also contracts,squeezing extra air out
62
What increases the frequency and depth of breathing
Exercise
63
How does the body make more energy
The cells in the muscles combine oxygen with glucose
64
What happens when the body reaches its limit in giving oxygen
When it reaches its limit,extra energy energy is provided by anaerobic respiration.the muscle cells continue to respire aerobically with the oxygen they have and they also break down glucose without combining with oxygen
65
What is the equation for breakdown of glucose without oxygen
Glucose —> lactic acid + energy (ATP)
66
What happens after you stop exercising
The lactic acid which is built up in the muscles need to be broken down by combining it with oxygen in the liver.this is done by aerobic respiration in the liver cells.so it combines with oxygen to repay the oxygen dept
67
What is oxygen debt
Extra oxygen that is needed after anaerobic respiration has taken place,in order to break down the lactic acid produced
68
What is controlled by the brain
Breathing rate
69
How does the brain monitor the breathing rate?
It monitors the pH of the blood that flows through it,if there is a lot of carbon dioxide of lactic acid then pH would fall.the brain sends a nerve impulse to the diaphragm and the inter coastal muscles making them contract harder and more often

IGCSE Biology (22 decks)

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