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Biology Paper 1 > B2 - Organisation > Flashcards

B2 - Organisation Flashcards

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1
Q

What is the order in which food passes through the digestive system?

A
  1. Mouth
  2. Oesophagus
  3. Stomach
  4. Small intestine
  5. Large intestine
  6. Rectum
  7. Anus
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2
Q

What is the function of the mouth in digestion?

A

To mechanically break up food pieces to increase the surface area of the food.

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3
Q

What are two functions of saliva in digestion?

A
  1. To moisten food to allow easier swallowing.
  2. To start chemical digestion by containing salivary amylase.
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4
Q

What is the function of stomach acid?

A

To kill potentially pathogenic microorganisms in food.

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5
Q

What is the function of the small intestine?

A

To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food.

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6
Q

Give an adaptation of :
a) the small intestine
b) cells lining the small intestine
to aid absorption of digested molecules.

A

a) Small intestine has structures called villi which increase surface area
b) Epithelial cells lining the villi have microvilli on their surface which further increase surface area.

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7
Q

What is the function of the large intestine?

A

To absorb water from digested food.

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8
Q

What is the function of the liver in digestion?

A

To produce bile, an emulsifying and neutralising substance.

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9
Q

What is the function of the gall bladder?

A

To store bile until it can be released into the small intestine.

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10
Q

What is an enzyme?

A

A protein which can catalyse a reaction (speed it up) without being used up itself.

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11
Q

What is a substrate?

A

A molecule or atom which is acted upon by an enzyme.

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12
Q

Name two environmental conditions that can change an enzyme’s active site.

A
  1. pH (either higher or lower than optimum)
  2. Higher than optimal temperature
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13
Q

What do carbohydrases break down and what is produced?

A

Carbohydrates to simple sugars (e.g. amylase breaks down starch to glucose).

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14
Q

What do proteases break down and what is produced?

A

Proteins to amino acids.

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15
Q

What do lipases break down and what is produced?

A

Lipids (fats) to fatty acids and glycerol.

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16
Q

What is the Benedict’s test and how do you carry it out?

A

For testing if there is sugar in food samples. Add Benedict’s reagent to the food sample, boil/heat, if glucose is present the colour will change to brick red/orange.

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17
Q

What is the Biuret test and how do you carry it out?

A

For testing if there is protein in food samples. Add Biuret reagent (blue liquid), If it turns lilac, protein is present.

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18
Q

Which food test can be carried out with iodine?

A

Testing for the presence of starch. If it turns blue/black, it contains starch.

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19
Q

Name the two types of chambers in the heart.

A

Atria and ventricles.

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20
Q

Which are the upper chambers of the heart?

A

Atria

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21
Q

What is the job of the heart valves?

A

To prevent backflow of blood in the heart.

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22
Q

Name the blood vessel by which blood arrives back from the rest of the body.

A

Vena cava

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23
Q

Name the blood vessel by which blood leaves the heart to go to the lungs.

A

Pulmonary artery.

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24
Q

Which blood vessels have thick walls containing muscle tissue and elastic fibers?

A

Arteries

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25
Which gas diffuses into the bloodstream?
Oxygen
26
Which gas diffuses out of the bloodstream?
Carbon dioxide
27
Name the structure which carries air from the nose/mouth.
Trachea
28
What are the small gas exchange structures in the lungs called?
Alveoli (singular: alveolus).
29
Describe four adaptations of the lungs to make them well suited for gas exchange.
1. Capillaries have thin walls (one cell thick), providing short diffusion pathway. 2. Extensive capillary network covering the surface of each alveoli, maintains a steep concentration gradient. 3. Alveoli have a folded surface which increases the surface area. 4. Many alveoli provide a large surface are to volume ration.
30
What are the three main cell types found in blood?
Red blood cells, white blood cells, platelets.
31
What does blood plasma transport from the organs to the lungs?
Carbon dioxide
32
What do platelets do?
Help clot the blood at wound sites.
33
What are haemoglobins function?
Carries oxygen to your bodies tissues and organs.
34
What occurs in Coronary Heart Disease (CHD)?
The coronary arteries become blocked with fatty deposits, narrowing them.
35
How do stents treat CHD?
They re-open the blocked coronary artery, restoring blood flow.
36
Why are faulty heart valves life-threatening?
Allows black-flow of blood.
37
When would an artificial heart be used?
1. To allow the heart to rest and recover. 2. To keep the patient alive whilst they wait for a transplant.
38
What is a risk factor?
A factor linked to an increased rate of disease.
39
What is cancer?
The uncontrolled growth and division of cells.
40
How do cancers develop?
DNA in cells is changed (mutated).
41
Name six plant tissues.
- epidermal - palisade mesophyll - spongy mesophyll - xylem - phloem - meristem
42
What is the function of the epidermis?
To cover and protect.
43
What is the function of the palisade mesophyll?
The site of photosynthesis.
44
What is the function of the spongy mesophyll?
Gas exchange.
45
What is the function of the xylem?
Transport of water and dissolved ions.
46
What is the function of the phloem?
Transport of sugars made in photosynthesis.
47
What is the function of the guard cells?
To allow gas exchange and control water loss.
48
What is transpiration?
Water and minerals are absorbed by the roots, transported up the plants, through the xylem, and out into the atmosphere.
49
What is the role of stomata and guard cells?
To allow gas exchange and control water loss.
50
What is translocation?
The movement of cell sap through the phloem.
51
What are two functions of bile?
To neutralise stomach acid. To break down fats during digestion.
52
Where are enzymes found?
Within a cell.
53
Give two reasons why translocation is important.
1. So that every part of the plant can have glucose which is needed for respiration. 2. So the glucose can be stored in summer in lower parts of the plant so in winter it can be given back to the leaves to continue with its growth.
54
What is cell sap?
A liquid made of mostly sugar and water.
55
Where are most of the stomata located in a leaf?
Underside
56
Why are most stomata located on the underside of a leaf?
To reduce water loss. Stomata on the top of the leaf releases a lot of water as a result of being exposed to sunlight/heat energy.
57
Why do the stomata open?
To allow gas exchange.
58
What factors affect the rate of transpiration?
Light intensity Air flow Water concentration in the soil
59
Why does air flow have an effect on transpiration?
The more air flow the lower the concentration of water outside the plant which creates a concentration gradient, meaning more water is lost.
60
Why does water concentration in the soil have an effect on transpiration?
More water to be absorbed through the roots meaning more water is ultimately lost.
61
Why does light intensity have an effect on transpiration?
More light means more stomata open to absorb the sunlight meaning more water is lost.
62
Why is glucose converted into starch in plant cells?
Because glucose is soluble, so it is converted into starch so that is can become insoluble and therefore cannot escape from the cell.
63
Explain the lock and key theory.
Enzyme's active site and substrate fit together as they are complementary shapes to allow the enzyme to break down the substrate.
64
Why won't some types of lipase fit with some lipids?
Active site is specific to the shape of only one type of molecule.
65
How is the loss of water through transpiration controlled?
Guard cells open and close the stomata.
66
Define double-circulatory system.
Blood is pumped to the lungs by the right side of the heart. Blood is pumped to the body by the left side of the heart.
67
What 3 organs produce carbohydrases?
Salivary gland Small intestine Liver
68
What is a cause for an anomalous result?
Scale/value was misread.
69
What are 5 functions of the liver?
Produces bile. Breaks down lactic acid. Amino acids broken down into urea. Breaks down toxins e.g. alcohol Forms glycogen stores.
70
What are the effects on the body when no bile is produced?
pH of small intestine will not be neutralised. Enzymes won't work effectively, causing weight loss, as fat stores will be used instead.
71
What is the effect of the build up of toxins in the body?
Poisoned body, pain, swollen liver.
72
What is the effect of a lack of glycogen stores on the body?
Cannot control blood glucose. Leads to diabetes.
73
3 ways the small intestine is adapted for efficient absorption.
Thin walls. Large SA. Many mitochondria for active transport.
74
How does diabetes cause body cells to lose water?
High concentration of glucose in blood. Water in cells moves out by osmosis. Through a partially permeable membrane.
75
Why does only having one ventricle make the circulatory system less efficient?
Oxygenated and deoxygenated blood mixes so less oxygen reaches the cells.
76
Why does the absence of carbohydrase lead to weight loss?
Less glucose available for respiration. Fat stores used instead.
77
Where is the pace maker located?
Right atrium.
78
Describe the structural difference between veins and arteries.
Arteries have a thicker layer of muscle. Veins have a thinner layer of elastic tissue. Veins have a wider lumen. Veins have valves.
79
What temperature are enzymes most effective at?
35 degrees celcius.
80
Why do enzymes not work well at low temperature?
Low kinetic energy. Fewer enzyme-substrate collisions.
81
What 3 parts of the human digestive system produce amylase?
Small intestine. Pancreas. Salivary gland.
82
What cells in a plant control water loss?
Guard cells.
83
What scientific word describes the movement of water through a plant?
Transpiration stream.
84
What change would decrease the rate of water loss from a plant?
Increased humidity.
85
Describe the structure of a xylem cell.
- Made of dead cells. - Don't have pores in their end walls. - Hollow and doesn't contain cytoplasm. - Contains lignin.
86
What is lignin?
A polymer found in cell walls of plants. Functions include water transport and mechanical support.
87
Describe the structure of a phloem cell.
- Made of living cells. - Have pores in their end walls. - Contains cytoplasm.
88
What are the similarities in the structure between xylem and phloem?
Both tubular and made of cells.
89
What is the function of the xylem cell?
- Transports water / mineral ions. - Involved in transpiration. - Transports unidirectionally.
90
What is the function of a phloem cell?
It transports (dissolved) sugars. It is involved in translocation. It transports bidirectionally.
91
What does bidirectionally mean?
Multiple directions that sugars travel.
92
What does unidirectionally mean?
One direction that water and mineral ions travel.
93
How does fewer red blood cells link to tiredness?
Less oxygen transported. Less aerobic respiration. Less energy used for metabolic processes. Lactic acid build up causing muscle fatigue.
94
What is bile's function?
To emulsify fats. To neutralise small intestine.
95
How does bile help the digestion of fats?
Emulsifies fats so the surface area is larger for lipase to break the fats down. Neutralises small intestine from an acid, so lipase is at optimum pH.
96
What is amylase a polymer of?
Smaller amino acid molecules.
97
What does the small intestine absorb?
carbohydrates lipids amino acids vitamins mineral ions

Biology Paper 1 (4 decks)

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