Organisation Flashcards
(112 cards)
1
Q
What are cells?
A
The basic building blocks of all living organisms.
2
Q
What are tissues?
A
Groups of cells with similar structure and function, which all work together to do a job.
3
Q
What are some examples of the functions of tissues?
A
- Muscle tissue contracts to produce movement.
- Glandular tissue produce substances such as enzymes and hormones.
- Epithelial tissue covers organs.
4
Q
What are organs?
A
Groups of different tissues, which all work together to perform a specific job.
5
Q
What does each organ contain? What does the stomach contain?
A
They may contain several tissues.
- Stomach:
• Muscle tissue that contracts to churn the contents.
• Glandular tissue to produce digestive juices.
• Epithelial tissue to cover the outside and inside of the stomach.
6
Q
What are organs organised into?
A
Organ systems.
7
Q
What are organ systems?
A
Groups of organs working together to perform a specific job.
8
Q
What is the digestive system?
A
An organ system in which several organs work together to digest and absorb food.
9
Q
What makes up an organism?
A
Lots of organ systems work together to make an organism.
10
Q
What are enzymes and what do they do?
A
Biological catalysts which speed up chemical reactions in living organisms.
11
Q
What are the properties of enzymes?
A
- They are large proteins
- There is a space within the protein molecule called the active site.
- Each enzyme catalyses a specific reaction.
- They work best at a specific temperature and PH called the optimum.
12
Q
What is the ‘lock and key theory’?
A
It is a model used to explain how enzymes work: the chemical that reacts is called the substrate (key) and it fits into the enzyme’s active active site (lock).
13
Q
What do high temperatures and extremes of PH do to enzymes?
A
They make enzymes change shape -> this is called denaturing.
14
Q
Why can the enzyme not work once it has been denatured?
A
Because the substrate can no longer fit into the active site -> the lock and key no longer fit together.
15
Q
Where are digestive enzymes produced?
A
They are produced by specialised cells in glands and the lining of the gut.
16
Q
How are digestive enzymes produced?
A
- The enzymes pass out of cells into the digestive system.
- They come into contact with food molecules.
- They catalyse the breakdown of large insoluble food molecules into smaller soluble molecules.
17
Q
What are the digestive enzymes and what do they break down?
A
- Protease which digests proteins
- Lipase which digests lipids
- Carbohydrase which digests carbohydrates
To produce smaller molecules that can be absorbed into the bloodstream.
18
Q
Where is amylase produced?
A
In the salivary glands and the pancreas.
19
Q
What is amylase?
A
A carbohydrate that breaks starch into sugar (maltose)
20
Q
Where is protease produced?
A
In the stomach, pancreas and small intestine.
21
Q
What does protease do?
A
Breaks down proteins into amino acids or peptides.
22
Q
Where is lipase produced?
A
Pancreas and small intestine.
23
Q
What does lipase do?
A
Breaks down lipids (fats) into fatty acids and glycerol.
24
Q
What can the products of digestion e.g. amino acids be used for?
A
To build new carbohydrates, lipids and proteins.
25
What is bile?
A liquid made in the liver and stored in the gall bladder.
26
What does bile do?
It is alkaline to neutralise hydrochloride acid from the stomach. It also emulsifies fat to form small droplets, increasing the surface area for enzymes to act on.
27
What increases the rate at which fat is broken down?
The alkaline conditions and large surface area increase the rate at which fat is broken down by lipase.
28
What does bile not contain?
Bile does not contain any enzymes, so it does not digest fat molecules, it breaks up fat molecules into smaller ones.
29
What is blood?
A tissue made of liquid called plasma, which has 3 different components suspended in it:
* Red blood cells
* White blood cells
* Platelets
30
What does plasma do?
It transports various chemical substances around the body, such as the products of digestion, hormones, antibodies, urea and carbon dioxide.
31
How are red blood cells adapted to their function?
- Contain haemoglobin, which binds to oxygen to transport it from the lungs to the tissues and cells, which need it for respiration.
- Do not contain a nucleus do there is more room for haemoglobin.
- Are very small, so they can fit through the tiny capillaries.
- Are shaped like biconcave discs, giving them a large surface area that oxygen can quickly diffuse across.
32
What do white blood cells do?
- Help to protect the body against infection.
- Can change shape, so they can squeeze out of blood vessels into the tissues or surround and engulf microorganisms.
- Platelets are fragments of cells, which collet are wounds and trigger blood clotting.
33
What are blood vessels?
The body passes blood around the body in blood vessels.
34
What are the 3 different types of blood vessels?
- Arteries
- Veins
- Capillaries
35
What do arteries do?
- Take blood from your heart to your organs.
| - Thick walks made from muscle and elastic fibres.
36
What do veins do?
- Take blood from your organs to your heart.
| - Thinner walls and valves to prevent back flow.
37
What do capillaries do?
- Allow substances needed by the cells to pass out of the blood.
- Allow substances produced by the cells to pass unto the blood.
- Narrow, thin-walled blood vessels.
38
What is the heart?
The heart is an organ that pumps blood around the body in a double circulatory system, blood passes the heart twice in each circuit,
there are 4 chambers of the heart.
39
What are the four chambers of the heart?
- The left and right atria
| - The left and right ventricles
40
What do the left and right atria do?
They receive blood from veins.
41
What do the left and right ventricles do?
They pump blood out to the arteries, the right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body.
42
What does blood enter the heart through?
The atria
43
How is blood forced into the ventricles?
The atria contract
44
What ensure that blood flows in the correct direction?
Valves
45
What is the natural resting heart rate controlled by?
A group of cells located in the atrium which act at a pacemaker.
46
What are artificial pacemakers?
Electrical devices used to correct irregularities in the heart rate.
47
Why is the pulmonary artery unusual?
Unlike other arteries it carries deoxygenated blood. The pulmonary vein carries deoxygenated blood. The pulmonary vein carries oxygenated blood.
48
How does the heart send blood to the lungs?
Via the pulmonary artery.
49
How does air obtained by breathing reach the lungs?
Through the trachea (windpipe)
50
What are the bronchi?
The trachea is divided into two tubes called the bronchi.
51
What are bronchioles?
The bronchi are divided to form bronchioles
52
What are alveoli?
The bronchioles divide until they end in tiny air sacs called alveoli.
53
How many alveoli are there?
Millions
54
How are alveoli adapted to be very efficient at exchanging oxygen and carbon dioxide?
- They have a large, moist surface area
- They have a very rich blood supply
- They are very close to the small blood capillaries, so the distance for the gases to diffuse is small.
55
How is blood taken back to the heart?
Through the pulmonary vein.
56
What is good health?
A state of physical and mental well-being
57
What are the two main types of disease?
Communicable and non-communicable diseases.
58
What are non-communicable diseases?
Diseases that cannot be spread between organisms but communicable diseases can.
59
How do viruses interact with other diseases?
Virus infecting cells can be the trigger for cancers e.g. cervical cancers.
60
What do defects/ diseases of the immune system mean that?
An individual is more likely to catch infectious diseases.
61
How can allergies be triggered?
Immune rashes triggered by a pathogen can cause allergies e.g. skin rashes, asthma
62
How can physical and mental illnesses interact?
If a person is physically ill this can lead to mental illness and depression.
63
How can lifestyle interact with disease?
Poor diet, stress, difficult situations can increase the likelihood of developing certain diseases.
64
How much of the health budget is spent on people with diabetes?
About 10%
65
What are non-communicable diseases often caused by?
A number of risk factors
66
What can risk factors be?
- Aspects of a person’s lifestyle e.g. lack of exercise
| - Substances in the person’s body/ environment e.g. chemicals from smoking.
67
How do scientists prove a risk factor is involved in a disease?
By looking for a causal mechanism.
68
What is a causal mechanism?
The process by which a cause brings about an effect a causal mechanism had been found that links smoking to lung cancer- it is the action of the chemicals in tar.
69
What are the proven risk factors of cardio vascular disease?
Lack of exercise, smoking, high intake of saturated fat
70
What are the proven risk factors of type 2 diabetes?
Obesity
71
What are the proven risk factors of liver and brain damage?
Excessive alcohol intake
72
What are the proven risk factors of lung disease, including lung cancer?
Smoking
73
What are the proven risk factors of skin cancer
Ionising radiation
74
What are the proven risk factors of low birth weight in babies?
Smoking during pregnancy
75
What are the proven risk factors of brain damage in babies?
Excessive alcohol intake during pregnancy
76
What does coronary heart disease do to the body?
Layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
77
What do treatments for coronary heart disease include?
- Stents to keep the coronary arteries open
| - Staints to reduce blood cholesterol levels and slow down the rate at which fatty materials build up.
78
What do faulty heart valves cause?
In some people, heart valves can become faulty, developing a leak of preventing the valve from opening fully.
79
What can faulty heart valves be replaced by?
Biological or mechanical valves.
80
For cases of heart failure...
- A donor heart or heart and lungs can be transplanted.
- Artificial heated can be used the keep patients alive while waiting for a heart transplant or to allow the heart to recover.
81
What sort of drugs are sometimes given to patients recovering from heart disease?
Clot-busting enzymes or warfin
82
What are staints used for?
To lower cholesterol levels
83
What sort of disease is cancer?
A non communicable disease
84
What is cancer caused by?
Uncontrollable cell division which can form masses of cells called tumours.
85
What are the two types of cancer?
Benign and malignant
86
What are benign tumours?
Tumours that do not spread around the body
87
What are malignant tumours?
Tumours which spread in the blood to different parts of the body where they form secondary tumours.
88
What does the epidermis do in a plant?
It covers outer surfaces of the plant for protection.
89
What does the palisade mesophyll do in a plant?
It is the main site of photosynthesis in the leaf.
90
What does spongy mesophyll do in a leaf?
They are air spaces between the cells which allow gases to diffuse through the leaf.
91
What do xylem vessels do?
They transport water and minerals through the plant from roots to leaves. Also supports the plant.
92
What do phloem vessels do?
Transports dissolves food materials through the plant.
93
What does meristem tissue do?
It is found mainly at the tips of the shoot as and roots where is can produce new cells for growth.
94
What is the leaf of a plant?
A plant organ
95
How does water enter a plant?
From the soil, through the root hair cells, by osmosis.
96
What are root hair, xylem and phloem cells specialised to do?
To transport water (containing dissolved minerals), minerals and sugars around the plant.
97
In which direction is water transported in plants?
Up the xylem vessels, from the roots, to stems and leaves.
98
What happens to water when it reaches the leaves of a plant?
Most of the water will evaporate and diffuse out of the stomata (small pores).
99
Where are stomata found in most plants?
They are mainly found on the bottom surface of the leaf. This means that sun does not directly shine on them, reducing water loss.
100
What is transpiration?
The loss of water from a plant through the leaves.
101
What does transpiration help?
It helps draw up water from the roots.
102
How will an increase in temperature affect the rate of transpiration?
It will increase it because more energy is transferred to the water to allow it to evaporate.
103
How will a faster air flow affect the rate of transpiration?
It will increase ur as it will blow away water vapour, allowing it to evaporate.
104
How will an increase in light intensity affect the rate of transpiration?
It increase it as it will cause the stomata to open.
105
What will an increase in humidity do to the rate of transpiration?
It will decrease the rate as the air contains more water vapour so the concentration gradient for diffusion it lower.
106
What does a guard cell do in the leaf?
It opens and closes the stomata.
107
Why are the stomata closed at night?
At night the stomata are closed because carbon dioxide is not needed for photosynthesis, so closing the stomata reduces water loss.
108
What do guard cells do when water is plentiful?
They take up water and bend, causing the stomata to open so gases for photosynthesis are free to move in and out of the stomata along with water from transpiration.
109
What happens when water is scarce in a plant?
When water is scarce, losing water makes the stomata change shape and close. This stops the plant losing more water through transpiration.
110
How can the rate of transpiration from a shoot be estimated?
By measuring the rate at which the shoot takes up water. This is only an estimate because not all of the water taken up by a shoot is lost- a very small % is used in leaf.
111
Why can plants not stop transpiration completely?
Because carbon dioxide is always needed for photosynthesis so water will always escape.
112
What is translocation?
When phloem tissue transports dissolved sugars from the leaves to the rest of the plant.
