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Biology > Unit 2 - Organisation > Flashcards

Unit 2 - Organisation Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is a cell?

A

The basic building block of a living
organism.

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2
Q

What is a tissue?

A

A group of cells with a similar structure and
function working together. For example,
muscular tissue contracts to bring about
movement.

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3
Q

What is an organ?

A

A collection of tissues working together to
perform a specific function. For example,
the stomach contains glandular, muscular
and epithelial tissues.

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4
Q

What is an organ system?

A

A group of organs working together to perform
specific functions. For example, the digestive
system contains organs such as the stomach,
the small intestine and the large intestine.

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5
Q

What is the main function of the digestive
system?

A

To digest food and absorb the nutrients
obtained from digestion.

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6
Q

What is the role of the pancreas and the salivary
gland in the digestive system?

A

The pancreas and the salivary gland are glands
which produce digestive juices containing
enzymes.

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7
Q

What is the role of the stomach in the digestive
system?

A

Produces hydrochloric acid - which kills any
bacteria present and provides the optimum
acidic pH for the protease enzyme to
function.

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8
Q

What is the role of the small intestine in the
digestive system?

A

The small intestine is the site where soluble
food molecules are absorbed into the
bloodstream.

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9
Q

What is the role of the liver in the digestive
system?

A

Produces bile (stored in the gallbladder)
which emulsifies lipids and allows the lipase
enzyme to work more efficiently.

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10
Q

What is the role of the large intestine in the
digestive system?

A

Absorbs water from undigested food,
producing faeces.

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11
Q

What is the role of enzymes in the digestive
system?

A

Enzymes act as biological catalysts which
speed up the rate of biological reactions (the
breakdown of food) without being used up.

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12
Q

How does the shape of an enzyme affect its
function?

A

Enzymes have a specific active site which is
complementary to their substrate.

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13
Q

What is metabolism?

A

The sum of all the reactions in a
cell or an organism.

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14
Q

What types of metabolic reactions do enzymes
catalyse?

A

● Building larger molecules from smaller molecules eg.
glucose to starch.
● Changing one molecule to another eg. glucose to
fructose.
● Breaking down larger molecules into smaller
molecules eg. carbohydrates to glucose.

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15
Q

What is the lock and key hypothesis of enzyme
function?

A

The shape of the enzyme active site and the
substrate are complementary, so can bind
together to form an enzyme-substrate
complex.

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16
Q

How does temperature affect enzyme action?

A

Up to a certain point, increasing temperature increases
enzyme action, as molecules have a higher kinetic
energy. Above a certain temperature, the shape of the
active site is altered and the enzyme becomes
denatured, so it can no longer catalyse the reaction. The
optimum temperature is around 37°.

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17
Q

How does pH affect enzyme function?

A

The optimum pH for most enzymes is 7 (apart
from proteases in the stomach). If the pH is too
extreme, the shape of the active site may be
altered and the enzyme may no longer work.

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18
Q

Where are carbohydrases, proteases and lipases
produced in the body?

A

● Carbohydrases: amylase - salivary gland and
pancreas; maltase - small intestine.
● Proteases: pepsin - stomach; others -
pancreas and small intestine.
● Lipases: pancreas and small intestine.

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19
Q

What is the role of carbohydrases in the digestive
system?

A

Carbohydrases break down carbohydrates into
monosaccharides and disaccharides. Amylase
breaks down starch into maltose, and maltase
breaks down maltose into glucose.

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20
Q

What is the role of proteases in the digestive
system?

A

Proteases break down proteins into amino
acids.

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21
Q

What is the role of lipases in the digestive
system?

A

Lipases break down lipids into fatty acids
and glycerol.

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22
Q

How are the products of digestion used?

A

They are used to build bigger molecules
such as carbohydrates and proteins.
Glucose is used as a substrate in
respiration.

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23
Q

Where is bile made and stored in the body?

A

Bile is made by the liver and stored in the
gallbladder

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24
Q

What is the role of bile in the digestive system?

A

● Bile is an alkaline substance which neutralises
the hydrochloric acid secreted by the stomach.
● Bile emulsifies lipids to form droplets - this
increases the surface area for the lipase
enzyme to work on.

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25
Q

What is the heart?

A

An organ that pumps blood around the
body

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26
Q

What is the purpose of the circulatory system?

A

Carries oxygen and other useful
substances to bodily tissues, and
removes waste substances.

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27
Q

How does the double circulatory system work?

A

● One pathway carries blood from the heart to
the lungs - where the gaseous exchange of
oxygen and carbon dioxide takes place.
● One pathway carries blood from the heart to
the tissues.

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28
Q

Where does blood pumped by the right
ventricle go?

A

The lungs

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29
Q

Where does blood pumped by the left
ventricle go?

A

Body tissues

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30
Q

Why is the double circulatory system important?

A

It makes the circulatory system more
efficient - for example, oxygenated blood
can be pumped around the body at a
higher pressure by the left ventricle.

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31
Q

How many chambers does the heart have and
what are they called?

A

4 - right atrium, right ventricle, left atrium,
left ventricle.

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32
Q

Why is the wall of the left ventricle thicker?

A

The left ventricle has to pump blood at a
higher pressure around the whole body.

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33
Q

What are the four main blood vessels associated with
the heart?

A

● Aorta (left) - carries oxygenated blood from the heart to the
body.
● Pulmonary vein (left) - carries oxygenated blood from the lungs
to the heart.
● Vena cava (right) - carries deoxygenated blood from the body to
the heart.
● Pulmonary artery (right) - carries deoxygenated blood from the
heart to the lungs.

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34
Q

What is the purpose of valves in the heart?

A

Prevent the backflow of blood

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35
Q

What is the purpose of coronary arteries?

A

Coronary arteries supply the heart
muscle with oxygenated blood.

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36
Q

Describe the process of blood flow through the heart

A

● Blood enters the right atrium via the vena cava, and the
left atrium via the pulmonary vein.
● The atria contract, forcing blood into the ventricles and
causing valves to shut.
● After the ventricles contract, blood in the right ventricle
enters the pulmonary artery (to the lungs) and blood in
the left ventricle enters the aorta (to the body).

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37
Q

What is the approximate value of the natural
resting heart rate?

A

70 beats per minute

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38
Q

How is the heart rate controlled?

A

Heart rate is controlled by a group of cells in
the right atrium which act as a pacemaker.
They release waves of electrical activity
which cause the heart muscle to contract.

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39
Q

How can an abnormal heart rhythm be treated?

A

Irregular heart rhythms can be treated
using an artificial pacemaker, which
sends out electrical signals to correct the
heart’s rhythm.

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39
Q

What are the three types of blood vessel in the
body?

A

● Arteries
● Veins
● Capillaries

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40
Q

How are arteries adapted for their function?

A

● Function: carry blood away from the heart.
● Thick muscle layer - adds strength to resist high
pressure.
● Thick elastic layer - allows arteries to stretch
and recoil - in order to withstand high pressure.

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41
Q

How are veins adapted for their function?

A

● Function: carry blood towards the heart
● Wide lumen - enables low pressure
● Valves - prevent backflow of blood

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42
Q

How are capillaries adapted for their function?

A

● Function: enable transfer of substances between
the blood and tissues.
● Walls are one cell thick - short diffusion path.
● Permeable walls - substances can diffuse across.
● Narrow lumen - blood moves slowly - more time
for diffusion.

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43
Q

How would you calculate the rate of blood flow?

A

Volume of blood / number of minutes

44
Q

Where are the lungs found in the body?

A

The lungs are located in the thorax (within the
chest). They are protected by the ribcage and
separated from the rest of the abdomen by
the diaphragm.

45
Q

Where are the lungs found in the body?

A

The lungs are located in the thorax (within the
chest). They are protected by the ribcage and
separated from the rest of the abdomen by
the diaphragm.

46
Q

What tissues make up the gas exchange system?

A

● Trachea
● Intercostal muscles
● Bronchi
● Bronchioles
● Alveoli
● Diaphragm

47
Q

Explain how the lungs are ventilated by the
action of intercostal muscles

A

● Oxygen diffuses from the alveoli into the
capillary bloodstream down its concentration
gradient.
● Carbon dioxide diffuses from the capillary into
the alveoli down its concentration gradient.

47
Q

Explain how the lungs are ventilated by the
action of intercostal muscles

A

● Intercostal muscles contract
● Ribcage moves upwards and outwards
● Diaphragm flattens and volume of the chest increases
● Increased volume results in decreased pressure
● Air is drawn into lungs down pressure gradient
The inverse occurs when air moves out of the lungs.

48
Q

Describe how alveoli are adapted for gas
exchange

A

● Small and arranged in clusters - larger surface
area.
● Rich blood supply - maintains concentration
gradient.
● Thin alveolar wall - short diffusion pathway.

49
Q

How would you calculate the breathing rate

A

Number of breaths / number of minutes

50
Q

What substance carries the different components of
blood around the body?

A

Plasma

51
Q

What substances are transported by plasma?

A

● Red blood cells
● White blood cells
● Platelets
● Carbon dioxide
● Urea
● Products of digestion

52
Q

What is plasma?

A

A yellow liquid within blood that
transports substances around the body.

53
Q

What is the purpose of red blood cells in blood?

A

Transport of oxygen around the body

54
Q

How are red blood cells adapted for their
function?

A

● Biconcave shape - increased surface area to
volume ratio.
● No nucleus - more room for haemoglobin to
bind to oxygen.
● Contain haemoglobin - binds to oxygen.

55
Q

What is the purpose of white blood cells in
blood?

A

They form part of the immune system,
which protects the body from invading
pathogens.

56
Q

How are white blood cells adapted for their
function?

A

● Have a nucleus - contains DNA which codes for
proteins
● Can produce antibodies
● Can produce antitoxins
● Can engulf and digest pathogens (phagocytosis)

57
Q

What is the purpose of platelets in blood?

A

Platelets are small cell fragments which aid
the clotting of blood at the site of a wound.

58
Q

Why is the function of platelets important?

A

● Platelets aid in the process of blood clotting
(conversion of fibrinogen to fibrin). As a result, red
blood cells are trapped in the fibrin network,
forming a clot which prevents excessive bleeding.
Scab formation (after the clot has dried) prevents
bacteria from entering the wound.

59
Q

What is coronary heart disease?

A

Coronary heart disease occurs when the
coronary arteries that supply the heart muscle
become blocked with a buildup of fatty material.
This restricts the supply of oxygen to the heart,
possibly leading to a heart attack or death.

60
Q

What is a stent and how does it work?

A

A stent is a metal mesh tube that is inserted
into a blocked artery so that it remains open.
The stent is inflated using a balloon, which is
later removed to allow blood to flow freely.

61
Q

What are the advantages and disadvantages of
stents?

A

Advantages
● Insertion can be carried out without general anaesthetic
● Quick recovery time
● Lower the risk of a heart attack
Disadvantages
● Risk of postoperative infection
● Risk of blood clots at site of stent

62
Q

What are statins?

A

Statins are drugs which reduce the level of
LDL (bad) cholesterol which contributes to
the development of coronary heart disease.

63
Q

What are the advantages and disadvantages of statins?

A

Advantages
● Reduce risk of strokes, coronary heart disease and heart
attacks
● Increase level of HDL (good) cholesterol
Disadvantages
● Have to be taken continuously
● May have side effects
● Effect may not be immediate

64
Q

What is a heart bypass surgery?

A

A surgery where blocked coronary
arteries are replaced with sections of
veins taken from other parts of the body.

65
Q

What are the consequences of leaky heart
valves?

A

Blood flows in the wrong direction, causing
the heart to become less efficient. Patients
may become breathless and die as a result.

66
Q

What types of valves can replace leaky valves?

A

● Mechanical - made of metal or polymers
● Biological - taken from animals (pigs,
sometimes humans)

67
Q

What are the advantages and disadvantages of
mechanical valves?

A

Advantages
● Last for a very long time
Disadvantages
● Need to take medication to prevent blood
clotting around valve

68
Q

What are the advantages and disadvantages of
biological valves?

A

Advantages
● Work very well - no medication required
Disadvantages
● Only lasts 12-15 years

69
Q

What is the purpose of an artificial heart?

A

Artificial hearts are intended to support a
patient’s heart while they wait for a suitable
donor heart.

70
Q

What are the advantages and disadvantages of
artificial hearts?

A

Advantages
● Less likely to be rejected by immune system
● Allows damaged heart to rest to help recovery
Disadvantages
● Risk of infection due to surgery
● Risk of blood clots
● Have to take blood-thinning drugs

71
Q

What is health?

A

Health is the state of physical and mental
wellbeing

72
Q

What is a communicable disease?

A

A disease caused by a pathogen which can
be transmitted from one person to another
eg. the flu.

73
Q

What is a non-communicable disease?

A

A disease which can not be transmitted
from person to person eg. cancer.

74
Q

How can diet affect health?

A

● Too little food / lack of nutrition - anaemia,
vitamin deficiencies.
● Too much food / too much unhealthy food -
obesity, type 2 diabetes.

75
Q

How can stress affect health?

A

Prolonged stress is linked to a wide range
of health problems including heart
diseases, cancers and mental health
issues.

76
Q

How can life situations affect health?

A

Many life factors such as location, gender,
financial status, ethnic group and
healthcare provision can impact a person’s
mental and physical health.

77
Q

Give examples of how health problems can interact

A

● Infection with certain viruses can lead to cancer eg. hepatitis
infections can lead to liver cancer.
● A compromised immune system (eg. due to cancer) can lead to
a higher risk of infection with communicable diseases.
● Immune reactions caused by a pathogen can trigger allergic
reactions.
● Problems with physical health can lead to mental health issues.

78
Q

What is a risk factor?

A

A risk factor is an aspect of a person’s lifestyle
or a substance found in the body or the
environment which can increase the risk of a
disease.

79
Q

What is a causal mechanism?

A

A mechanism which demonstrates how one
factor biologically influences another.

80
Q

How do diet, smoking and exercise affect the
development of cardiovascular disease?

A

● Diet: high levels of LDL cholesterol causes arteries to
become blocked, increasing blood pressure and the risk of
a heart attack.
● Smoking: nicotine increases heart rate; other chemicals
damage the artery lining and increase blood pressure.
● Exercise: lowers blood pressure, reducing strain on the
heart.

81
Q

How does obesity affect the development of type 2
diabetes?

A

● Obesity is strongly linked with the onset of
type 2 diabetes - a disease in which the body
stops responding to insulin.

82
Q

How does alcohol affect liver and brain function?

A

● Excessive long-term alcohol use may lead
to liver cirrhosis (scarring of the liver).
● Increases risk of liver cancer.
● Damages brain tissue and nerve cells.

83
Q

How does smoking affect the development of
lung disease and lung cancer?

A

● Tar in tobacco can damage the alveoli of the
lungs, leading to chronic obstructive
pulmonary disease (COPD).
● Tar also damages the cells which line the
lungs, leading to lung cancer.

84
Q

How do smoking and alcohol affect unborn babies?

A

● Carbon monoxide from tobacco smoke reduces the
amount of oxygen the foetus receives, which can lead
to premature birth or stillbirth.
● Alcohol passes across the placenta and damages the
developing foetus. Once born, the baby may have a
number of deformities and health problems as part of
foetal alcohol syndrome.

85
Q

How do carcinogens affect the development of
cancer?

A

Ionising radiation is a type of carcinogen
which can cause mutations in DNA, potentially
leading to cancer.

86
Q

What is cancer?

A

Cancer is the development of a tumour
as a result of uncontrolled cell division.

87
Q

What is cancer?

A

Cancer is the development of a tumour
as a result of uncontrolled cell division.

88
Q

What is a benign tumour?

A

● A tumour that is contained in one location,
usually within a membrane.
● They are not cancerous and do not invade other
parts of the body.
● Can grow large very quickly - may cause
damage to another organ.

89
Q

What is a malignant tumour?

A

● A tumour that can spread around the body via
the blood and lymphatic system.
● Can invade other tissues (metastasis).
● Cells divide more rapidly and have a longer
lifespan.
● Disrupts healthy tissues and may lead to death.

90
Q

Give examples of factors which can lead to
cancer

A

● Genetics - certain genes increase the risk of breast
and ovarian cancer
● Smoking
● Obesity
● Ionising radiation - UV light and X-rays
● Viral infections - HPV and cervical cancer

91
Q

How is epidermal tissue adapted for its function?

A

Epidermal tissue covers the entire plant. It
has a waxy cuticle which helps reduce water
loss from the leaf surface.

92
Q

How is palisade mesophyll tissue adapted for
its function?

A

Palisade mesophyll tissue contains lots of
chloroplasts which allows photosynthesis to
progress at a rapid rate.

93
Q

How is spongy mesophyll tissue adapted for its
function?

A

Spongy mesophyll tissue has lots of air
spaces which allow gases (including
oxygen and carbon dioxide) to diffuse in
and out.

94
Q

How is the xylem adapted for its function?

A

● Made up of dead cells which form a continuous
hollow tube - allows the movement of water and
mineral ions from the roots to the leaves.
● Strengthened by lignin - makes the vessel strong and
waterproof.
● Has bordered pits - allow minerals to be transported
to specific places.

95
Q

How is the phloem adapted for its function?

A

● Made up of elongated living cells.
● Cells have sieve plates that connect them
together - cell sap can move through plates
into other cells.
● Sieve tube cells have few organelles to allow
the efficient transport of substances

96
Q

How is meristem tissue adapted for its function?

A

Made up of stem cells which can
differentiate into many different cell types,
allowing the plant to grow.

97
Q

What tissues does the leaf organ contain?

A

● Epidermis
● Palisade mesophyll
● Spongy mesophyll
● Xylem
● Phloem
● Guard cells

98
Q

What is the function of guard cells?

A

Guard cells control the opening and closing
of the stomata, according to the water
content of the plant.

99
Q

How are stomata adapted for their function?

A

Stomata allow the control of gaseous exchange and
water loss from the leaf.
● More stomata on the base of the leaf - minimises
water loss as this side is cooler and shaded.
● Have guard cells which control their opening and
closing.

100
Q

How are root hair cells adapted for their function?

A

Root hair cells allow the uptake of water and
mineral ions from the soil.
● Large surface area - maximises rate of
absorption.
● Contain lots of mitochondria – release energy
for active transport of mineral ions.

101
Q

What is transpiration?

A

Transpiration is the evaporation of water
vapour from the surface of a plant.

102
Q

What is translocation?

A

Translocation is the movement of
dissolved sugars from the leaves to other
parts of the plant.

103
Q

How does transpiration work?

A

● Water evaporates from the leaf surface via the
stomata.
● Water molecules cohere together - more water is
pulled up the xylem in an unbroken column.
● More water is taken up from the soil - creating a
continuous transpiration stream.

104
Q

How does temperature affect the rate of transpiration?

A

Increasing the temperature increases the rate
of transpiration.
● Higher rate of evaporation and diffusion of
water - therefore rate of transpiration is
increased.

105
Q

How does humidity affect the rate of transpiration?

A

Increasing relative humidity decreases the rate of
transpiration.
● High relative humidity will reduce the water
vapour concentration gradient. The rate of
evaporation will decrease, and so will the rate of
transpiration.

106
Q

How does wind speed affect the rate of transpiration?

A

Increasing wind speed/air movement increases the
rate of transpiration.
● Increased air movement lowers water vapour
concentration outside of the leaf. This increases the
water vapour concentration gradient, thereby
increasing the rate of evaporation and transpiration.

107
Q

How does light intensity affect the rate of
transpiration?

A

Increasing the light intensity increases the rate of
transpiration.
● The rate of photosynthesis increases, so more
stomata open. This allows the rate of evaporation
to increase, increasing the rate of transpiration.

Biology (7 decks)

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