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Biology year 1 > 6.0 Exchange > Flashcards

6.0 Exchange Flashcards

1
Q

Explain one advantage of concaved red blood cell compared to a spherical one.

A

greater surface area for oxygen diffusion

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2
Q

Describe two features of specialised exchange surfaces.

A

large surface area to volume ratio. Very thin so shorter diffusion distance. Movement of environmental medium to maintain concentration gradient. Effective internal trasnport system to ensure diffusion gradient is maintained.

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3
Q

How do you calculate the surface area of a cube?

A

Area of one side (length x length) x 6 sides

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4
Q

How do you calculate the volume of a cube?

A

Length x width x height

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5
Q

How do you calculate the ratio of surface area to volume of a cube?

A

Surface area / volume

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6
Q

How do you calculate the surface area of a sphere?

A

4 π r^2

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7
Q

How do you calculate the volume of a sphere?

A

4/3 π r^3

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8
Q

What is the equation given for diffusion?

A

diffusion = (surface area x difference in concentration) / length of diffusion path

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9
Q

How does mass transport of oxygen occur in insects?

A

Contraction of muscles through abdominanl pumping enabling mass movements of air in and out

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10
Q

How does oxygen reach the working muscles in an insect?

A

Through the tracheoles

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11
Q

What is the advantage of having water at the end of tracheoles?

A

In periods of high activity, anaerobic respiration will create lactate which will reduce the water potential of respiring cells causing them to take up water by osmosis. This loss of water from the tracheoles means gas is further inside them.

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12
Q

What are the tiny pores that gases enter and leave the insect via?

A

spiracles

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13
Q

What are the three ways gases move in and out of the tracheal system?

A

1- Along the diffusion gradient.
2 - Mass transport.
3 - Movement of the water at the end of the tracheoles.

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14
Q

Why are the insect’s spiracles generally closed?

A

To prevent water loss.

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15
Q

What are the main structure of gills?

A

gill filaments

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16
Q

What increases the surface area of the gills?

A

they have lots of gill filiaments with lots of gill lamellae on them

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17
Q

Describe how countercurrent flow allows for effective gaseous exchange.

A

Blood flows in the opposite direction to water. Ensures there is always a diffusion gradient between water and the gills allowing maximum uptake of oxygen

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18
Q

Explain how parallel flow decreases gaseous exchange.

A

Oxygen can only be absorbed by diffusion at the start where oxygen concentration in the water is higher than in the blood. Equilibrium is quickly reached.

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19
Q

What are the two process which require gases in a plant?

A

Photosynthesis and respiration

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20
Q

How is a leaf adapted for gas exchange?

A

1 - many small pores (stomata) for short diffusion pathway.
2 - lots of are spaces in the mesophyl layer for movement of gases
3 - Large surface area of mesophyl cells

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21
Q

During daytime, what is the exchange of gases in and out of the plant? Why?

A

Carbon dioxide in and oxygen out. Due to photosynthesis. Respiration doesn’t create enough carbon dioxide or use enough oxygen.

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22
Q

During night time, what is the exchange of gases in a plant? Why?

A

Carbon dioxide out and oxygen in. Respiration is still occuring, photosynthesis is not.

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23
Q

How are the gas exchange systems of plants similar to insects?

A

1 - The cells using the gases are close to the external air.
2 - Diffusion occurs in the gas phase, not water. 3 - Pores for air to enter and leave.

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24
Q

Where are stomata mainly found?

A

Bottom side of the leaf to limit evaporation and transpiration

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25
What cell controls the opening and closing of stomata?
Guard cells
26
What is a disadvantage to having open stomata?
Excessive water loss
27
What is the name of the plants that are well adapted to dry environments?
Xerophytes
28
How do insects reduce water loss? Explain one example.
Small surface area to volume ratio, waterproof coverings, spiracles that can be opened and closed
29
What is the process known as when a plant loses water?
Transpiration
30
How does a thick cuticle reduce transpiration?
It is a waterproof barrier which increases diffusion distance
31
How does rolled up leaves reduce transpiration?
The stomata end up on the inside part of the leaf. this means water vapour becomes trapped and the air is saturated with water. It has a high water potential removing the water potential gradient between inside and outside the leaf.
32
How does having hairy leaves reduce transpiration?
These trap moisture near to the leaf, increasing water potential in the air, and reducing the water potential gradient. Less water is therefore evaportated.
33
How does having stomata in pits or grooves reduce transpiration?
Water vapour is trapped in the pit/groove. This increases the water potential in the air, and reduces the water potential gradient. Less water is therefore evaportated.
34
How does having a reduced surface area to volume ratio in the leaves of the plant reduce transpiration? What is a drawback of this adaptation?
The smaller the surface area to volume ratio, the slower the rate of diffusion. This slows evaporation. But has to be balanced against surface area for photosynthesis.
35
Suggest why must humans have a high rate of gaseous exchange?
Because they have a large volume of cells and have to maintain a high body temperature (related to high metabolic rate)
36
What are the lungs made of?
Bronchioles and alveoli
37
What is the airway from the mouth/nose to the lungs?
Trachea
38
Why is the trachea supported by a ring of cartilage?
To prevent it collapsing when air pressure inside is low
39
What are the bronchi?
The two divisions of the trachea, each leads to a lung.
40
What are bronchioles?
Branching divisions of the bronchi, getting smaller, leading to alveoli.
41
What are bronchioles made of? Why?
Branching divisions of the bronchi, getting smaller, leading to alveoli.
42
What is the role of goblet cells and cilliated cells in the bronchi?
Goblet cells produce mucus to trap dirt/dust/pathogens. Cilliated cells waft the mucus back up the throat to be swallowed.
43
What allows the alveoli to stretch and recoil?
Elastic fibres
44
During inspiration which muscles contract and which relax?
External intercostal muscles and diaphragm contract. Internal intercostal muscles
45
During expiration which muscles contract and which relax?
Internal intercostal muscles contract. External intercostal muscles and diaphragm relax.
46
What happens to the rib cage during inhalation?
The ribcage moves upwards and outward increasing the volume of the thorax.
47
What happens to the ribcage during exhalation?
The ribcage moves downwards and inwards, decreasing the volume of the thorax.
48
What happens to the pulmonary (of the lungs) pressure during inhalation?
The pressure in the lungs (pulmonary) decreases as thoracic volume increases. Atmospheric pressure is greater, so air is forced into the lungs.
49
What happens to the pulmonary (of the lungs) pressure during exhalation?
The pressure in the lungs (pulmonary) increases as thoracic volume decreases. Atmospheric pressure is lower, so air is forced out of the lungs.
50
During normal breathing, how is air expelled from the lungs?
The elastic recoil of the lungs is generally enough, alongside the relaxation of the external intercostal muscles and diaphragm.
51
How do you calculate pulmonary ventilation?
pulmonary ventilation = tidal volume x breathing rate
52
What is tidal volume?
The volume of air normally taken into the lungs each breath during rest.
53
Where are gases exchanged in mammals?
The epithelium of the alveoli
54
Why is there a short diffusion distance in the lungs?
The epithelial cells of the alveoli and the endothelial cells of the cappilaries are very thin. The red blood cells are flattened against the cappilary walls.
55
What happens to the red blood cells in the capillaries which increases gaseous exchange?
They flatten themselves against the side of the capillary resulting in a shorter diffusion distance. they move slowly to increase diffusion time.
56
How is a concentration gradiaent maintained in the lungs?
Breathing ventilates the lungs. The heart circulates the blood around the alveoli.
57
How is surface area increased in the lungs?
The high number of alveoli (300m per lung) and a network of pulmonary capillaries surounding each alveoli.
58
What are the main risk factors for lung disease?
Smoking, air pollution, genetic make-up, infections, occupation.
59
What is the difference between correlation and causation?
Correlation is when one variable changes, there is a change in another variable. Causation is when one variable changes, it causes a change in the second variable.
60
Why can we not say that correlation is the same as causation?
There may be other factors at play that have created the correlation between the two variables. The may not affect each other, but have both been affected by something else.
61
What are the main parts of the digestive system?
Oesophagus, stomach, ileum, large intestine, rectum, salivary glands, pancreas.
62
What are the two types of digestion?
Chemical and physical
63
What is the advantage of physical breakdown before chemical breakdown?
Increases surface area for chemical digestion
64
What reaction do digestive enzymes catalyse?
Hydrolysis
65
What is hydrolysis?
The splitting of molecules by adding water
66
What are the main types of hydrolytic enzymes?
Carbohydrases, lipases and proteases
67
What is a disaccharidase?
A hydrolytic enzyme which breaks up a disaccharide into a monosaccharide
68
What are the two enzymes involved in starch digestion?
Amylase (starch -> maltose) and maltase (Maltose -> alpha glucose)
69
Where is amylase found?
Salivary glands and pancreatic juice.
70
Where is maltase found?
It is membrane bound. Part of the cell-surface membrane of the epithelial cells lining the illeum.
71
Besides maltase, what other disaccharidases are present in our illeum? What do they digest?
Sucrase (sucrose -> glucose and fructose), Lactase (lactose -> glucose and galactose).
72
What are lipids digested into?
Fatty acids and monoglycerides
73
What do the bile salts do? what is this process called?
splits lipids into droplets, increasing their surface area - this is emulsification
74
What process increases the surface area of lipids?
emulsification
75
What is a peptidase?
Another term for a protease. A hydrolytic enzyme which breaks down proteins.
76
What are proteins broken down into?
Amino acids
77
What does an endopeptidase hydrolyse?
The peptide bond in the central region of a protein molecule. Making peptides.
78
What does exopeptidase hydrolyse?
The terminal amino acids from a peptide. - Creating amino acids and dipeptides
79
What does a dipeptidase hydrolyse?
The bond between the two mino acids of a dipeptide.
80
Which of the peptidases are membrane bound? What does this mean?
Dipeptidases are membrane bound. They are found on the cell-surface membrane of the epithelial cells of the illeum.
81
What are the folds called in the ileum and what's their purpose?
Villi, they increase absorption of nutrients.
82
What is the lumen of the illeum?
The cavity, or hole, on the inside of the illeum.
83
What are the adaptations of villi?
Thin wall - short diffusion distance; contain muscle to mix illeum contents - increase concentration gradient; high blood supply - increases concentration gradient; have microvilli - increase surface area.
84
By what process are amino acids and monosaccharides absorbed?
Co-transport
85
What are the basic steps of co-transport?
1 - Na+ ions actively transported out of the cell into the bloodstream.. 2 - This causes diffusion of Na+ ions into the cell from the illeum lumen as a concentration gradient is created. 3 - Na+ diffuses through a carrier protein wich a glucose molecule. 4 - Glucose moves into the blood steam via facilitated diffusion.
86
What is the first stage in lipid digestion?
Emulsification into lipid droplets.
87
Why are lipid droplets formed?
To increase the surface area for enzyme action.
88
What is formed when the lipids are digested by lipases?
Monoglycerides and fatty acids.
89
What is formed from the monoglycerides, bile salts and fatty acids?
Micelles
90
What is the role of a micelle?
They carry the monoglycerides and fatty acids to the cell surface membrane.
91
How do fatty acids cross the cell surface membrane?
They are non-polar molecules, so move through simple diffusion.
92
When the fatty acids and monoglycerides have crossed the cell surface membrane into an epithelial cell, what happens to them?
They are transported to the endoplasmic reticulum where they are reformed into triglycerides.
93
When triglycerides have been formed in the epithelial cell, what is the next stage in absorption?
They move to the golgi apparatus, where they are modified and combined with proteins to form lipoproteins and packaged into vesicles for exocytosis.
94
What are the vesicles called which are formed from triglycerides, proteins and cholesterol for absorption into the blood?
Chylomicrons
95
How do chylomicrons take lipids out of the epithelial cells?
They leave through exocytosis. They move into lacteals, which are lymph vessels. these transport them to the bloodstream.

Biology year 1 (10 decks)

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