Topic 2: Organisation Flashcards
1
Q
What is a cell?
A
Basic building blocks of all living organisms
2
Q
What is a tissue?
A
A group of similar cells working together to carry out a particular function
3
Q
What is an organ?
A
A group of different tissues working together to carry out a particular function
4
Q
What is an organ system?
A
A group of organs working together to carry out a particular function
5
Q
What do enzymes act as?
A
Biological catalysts
6
Q
What is a catalyst?
A
A substance which increases the speed of a reaction, without being changed or used up in the reaction
7
Q
Explain how the ‘lock and key’ theory works? [3]
A
- Each enzyme has an active site with a shape that fits a substrate
- Enzymes are specific - one type of enzyme will only fit one type of substrate
- When the substrate binds to the active site, it breaks up to form the products
8
Q
Was does the ‘induced fit’ model of enzyme action state?
A
That the active site changes shape a little to secure the substrate
9
Q
Explain why temperature increases enzyme activity up to a certain point?
A
The enzymes and substrates move around faster meaning there are more collisions per second
10
Q
Why is the name for the temperature when enzyme activity is at its highest?
A
Optimum temperature
11
Q
What happens to the rate of enzyme activity after the optimum temperature? [3]
A
- The rate decreases
- This is because the enzymes denature
- The shape of the active site is changed so the substrate can no longer fit
12
Q
What happens if the pH is too high or low for enzyme activity? [2]
A
- The enzyme denatures
- The shape of the active site is changed so the substrate can no longer fit
13
Q
What is the equation for the rate of a reaction?
A
Rate = 1000/time
14
Q
Why do starch, proteins and fats have to be broken down by digestive enzymes?
A
The molecules are too big to pass through the walls of the digestive system
15
Q
Starch
i) Broken down by?
ii) Into what?
A
i) Amylase
ii) Maltose
16
Q
Proteins
i) Broken down by?
ii) Into what?
A
i) Protease
ii) Amino acids
17
Q
Lipids
i) Broken down by?
ii) Into what?
A
i) Lipase
ii) Glycerol and fatty acids
18
Q
Where is amylase made?
A
- Salivary glands
- Pancreas
- Small intestine
19
Q
Where is protease made?
A
- Stomach
- Pancreas
- Small intestine
20
Q
Where is lipase made?
A
- Pancreas
- Small intestine
21
Q
What is protease called in the stomach?
A
Pepsin
22
Q
Where is bile produced?
A
Liver
23
Q
Where is bile stored?
A
Gall bladder
24
Q
Where is bile released?
A
Small intestine
25
# Write and check
How does bile aid digestion? [4]
1. Bile is alkaline, so it neutralises stomach acid and makes conditions in the small intestine alkaline
2. The enzymes of the small intestine work best in these alkaline conditions
3. Bile also breaks down fats into tiny droplets
4. This gives a bigger surface area of fat for the enzyme lipase to work on, making digestion faster
26
What is the test for sugars?
Benedict's
27
What colour change will occur if sugar is present?
Blue ---> green, yellow, red
(depends how much sugar present)
28
What is the test for starch?
Iodine
29
What colour change will occur if starch is present?
Orange ---> blue-black
30
What is the test for proteins?
Biuret
31
What colour change will occur if protein is present?
Blue ---> purple
32
What is the test for lipids?
Ethanol
33
What colour change will occur if lipids are present?
Colourless ---> cloudy white
34
# Write and check
Describe the pathway of air when you breath in? [5]
1. Air passes through our mouth or nose
2. Then down our trachea
3. It then divided between our two bronchi
4. It then divided further into branch-like structures known as bronchioles
5. It finally reaches small sacks known as alveloi, which carry out gas exchange
35
Describe the gas exchanges than occur across the alveoli [2]
1. Oxygen diffuses out of the alveolus (high conc) into the blood (low conc)
2. Carbon dioxide difusses out of the blood (high conc) into the alveolus (low conc)
36
Explain how oxygen diffuses into cells
When blood reaches body cells oxygen is released from red blood cells (high conc) and diffuses into the body cells (low conc)
37
Explain how carbon dioxide diffuses out of cells
Carbon dioxide diffuses out of body cells (high conc) into the blood (low conc)
38
How do you calculate breathing rate?
No. of breaths/no. of minutes
39
# Write and check
Describe the pathway of deoxygenated blood through the heart [4]
1. Blood flows into the vena cava
2. Then into the right atrium
3. The right atrium contracts pushing the blood into the right ventricle
4. The ventricle contracts, forcing the blood out of the heart and to the lungs via the pulmonary artery
40
Describe the pathway of oxygenated blood through the heart [4]
1. Blood flows into the pulmonary vein
2. Then into the left atrium
3. The left atrium contracts pushing the blood into the left ventricle
4. The ventricle contracts, forcing the blood out of the heart and to the rest of the body via the aorta
41
Which side of the heart pumps deoxygenated blood to the lungs?
Right
42
Which side of the heart pumps oxygenated blood to the rest of the body?
Left
43
What is the function of the coronary arteries?
They supply oxygenated blood to the heart itself
44
What is the natural resting heart rate controlled by?
A group of cells in the right atrium
45
How do the cells in the right atrium act as a pacemaker?
They produce small electrical impulses which spread to the surrounding muscle cells, causing then to contract
46
How does an artificial pacemaker work? [2]
1. The little device is implanted under the skin and has a wire going to the heart
2. It produces an electrical current to keep the heart beating regularly
47
What is the function of arteries?
To carry blood away from the heart
48
What is the function of veins?
To carry blood to the heart
49
What is the function of capillaries?
To exchange materials at tissues
50
How are arteries adapted to perform their function? [3]
1. Walls are thick compared to the size of the lumen
2. Walls contain thick layers of muscle - strong
3. Walls contain elastic fibres - allow them to stretch and spring back
51
What is blood pressure like in arteries?
High
52
How are veins adapted to perform their function? [3]
1. Thin walls
2. Large lumen
3. Valves
53
What is blood pressure like in veins?
Low
54
Why does the heart need valves?
To stop blood flowing in the wrong direction
55
What do capillaries branch off?
Arteries
56
How are capillaries adapted to perform their function? [2]
1. Permeable walls - allows substances to diffuse in and out
2. One cells thick walls - decreases the distance of diffusion, increasing rate
57
How would you calculate the rate of blood flow?
Volume of blood/no. of minutes
58
What is the job of red blood cells?
To carry oxygen from the lungs to the body cells
59
How are red blood cells adapted to perform their function? [2]
1. Biconcave shape - large SA for absorbing oxygen
2. No nucleus - allows more rrom to carry oxygen
60
What is the red pigment in blood called?
Haemoglobin
61
What happens to haemoglobin in the lungs?
It binds to oxygen to become oxyhaemoglobin
62
What happens to oxyhaemoglobin in body tissues?
It splits into oxygen and haemoglobin to release oxygen into the cells
63
What are 3 things a white blood cell can do?
1. Engulf unwelcome microorganisms
2. Produce antibodies to fight microorganisms
3. Produce antitoxins to neutralise toxins produced by microorganisms
64
What is the name of the process by which white blood cells engulf unwelcome microorganisms?
Phagocytosis
65
Do white blood cells have a nucleus?
Yes
66
What are platelets?
Small fragments of cells
67
Do platelets have a nucleus?
No
68
What is the function of platelets? [2]
1. To help blood clot at a wound
2. Stop blood pouring out and stop microorganisms getting in
69
What can a lack of platelets cause? [2]
1. Excessive bleeding
2. Bruising
70
What is the function of plasma?
To carry everything in blood
71
What happens in coronary heart disease? [4]
1. Layers of fatty material build-up inside the coronary arteries
2. This causes the arteries to become narrow
3. Reduces the flow of blood through the arteries
4. Results in a lack of oxygen to the heart muscle
72
What can coronary heart disease result in?
A heart attack
73
How can stents be used to treat coronary heart disease? [4]
1. Stents are tubes inserted inside arteries
2. They push the artery wall out, squashing fatty deposit
3. This keeps the artery open
4. Ensures the supply of oxygenated blood to the heart is not interrupted
74
Advantages of stents [3]
1. Lowers the risk of a heart attack
2. Effective for a long time
3. Quick surgery and recovery time
75
Disadvantages of stents [3]
1. Risk of complications during operation (e.g. heart attack)
2. Risk of infection from surgery
3. Risk of blood clots developing
76
What do statins do? [2]
1. Reduces the amount of bad cholesterol in the blood
2. Slows down the rate of fatty deposits forming
77
Advantages of statins [3]
1. Lowers the risk of coronary heart disease and heart attacks
2. Can increase the amount of good cholesterol
3. May prevent some other diseases
78
Disadvantages of statins [3]
1. Long-term drug, must be taken regularly - risk of someone forgetting to take them
2. Side effects e.g. headaches, kidney failure
3. Effect isn't instant
79
What does good cholesterol do in the blood?
Removes bad cholesterol
80
In what 2 circumstances is an artifical heart usually used?
1. Keep a person alive waiting for a donor heart
2. To help a person recover by allowing the heart to rest and heal
81
What is the main advantage of an artificial heart?
Less likely to be rejected than a donor heart
82
Disadvantages of an artificial heart [3]
1. Surgery can lead to bleeding and infection
2. Don't work as well as natural hearts - mechanics can fail
3. Patients have to take blood thinners - can cause problems with bleeding if hurt
83
What 3 things can cause faulty valves?
1. Heart attacks
2. Infection
3. Old age
84
What are the 2 types of replacement valves?
1. Taken from human or other mammals
2. Man-made
85
What is the main advantage of replacing a valve?
Less drastic procedure than a whole heart transplant
86
What is the main disadvantage of replacing a valve?
Still a major surgery which can lead to blood clots
87
How can a faulty heart valve lead to poor blood circulation? [2]
1. Valves may not be able to open properly, meaning less blood can flow through them
2. They can become leaky, meaning blood is able to flow in both directions
88
Define 'health'
State of mental and physical well-being
89
What is a communicable disease?
Those that can spread from a person to person or between animals and people
90
What is a non-communicable disease?
Those that cannot spread between people or between people and animals
91
What is the main cause of ill health?
Diseases
92
What other factors affect health? [3]
1. Diet
2. Stress
3. Life situation
93
What knock-on effect can defects in the immune system cause?
An individual is more likely to suffer from infectious diseases
94
What knock-on effect can ill physical health cause?
Poor mental health
95
What knock-on effect can viruses living in cells cause?
Cancer
96
What knock-on effect can an immune response to a pathogen cause?
Trigger allergies (e.g. skin rash or asthma)
97
What is a risk factor?
Things that are linked to an increase in the likelihood that a person will develop a certain disease
98
What can smoking cause? [3]
1. Cardiovascular disease
2. Lung disease
3. Lung cancer
98
What are the 2 categories for risk factor?
1. Aspects of a peron's lifestyle
2. Substances in the person's body or environment
99
How does smoking cause cardiovascular disease?
It damages the walls of the arteries
100
How does smoking cause lung cancer/disease?
Damages the cells in the lining of the lungs
101
What can obesity cause?
Type 2 diabetes
102
What can drinking too much alcohol cause? [2]
1. Liver disease
2. Brain damage
103
What will the affect of smoking/drinking while pregnant have?
Cause health problems for the baby
104
What can cause cancer?
Exposure to radiation
105
What is the human cost of non-communicable diseases? [2]
1. People with disease may have a lower quality of life
2. Can cause stress to loved ones
106
What is the financial cost of non-communicable diseases? [2]
1. Cost to the NHS treating diseases
2. More time off work leading to Government having to give financial support
107
What is cancer?
Uncontrolled cell growth and division
108
Characteristics of benign tumours [3]
1. Tumour stays in one place - doesn't invade other tissues
2. Isn't normally dangerous
3. Tumour isn't cancerous
109
Characteristics of malignant tumours [3]
1. Tumour grows and spreads to neighbouring healthy tissues - forming secondary tumours
2. Dangerous
3. Tumour is cancerous
110
What are 3 lifestyle risk factors of cancer?
1. Smoking
2. Obesity
3. UV exposure
111
What is an example of genetics increasing the likelihood of cancer?
Mutations in the BRCA genes have been linked to an increased likelihood of developing breast and ovarian cancer
112
Why is the epidermal tissue covered with a waxy cuticle?
Reduces water loss by evaporation
113
Why is the upper epidermis transparent?
Allows light to pass through to the palisade layer
114
Why is the palisade layer near the top of the leaf?
So they can receive the most light to carry out photosynthesis
115
Why are there air spaces in the spongy mesophyll?
Increase the rate of diffusion of gases
116
Why does the lower epidermis have little holes called stomata?
To let CO₂ diffuse directly into the leaf
117
What does the phloem transport?
Food
118
What does the xylem transport?
Water and mineral ions
119
What is translocation?
The process by which the phloem transports food substances made in the leaves to the rest of the leaf for immediate use or storage
120
What is transpiration?
The movement of water from the roots, through the xylem and out of the leaves
121
What is the xylem strengthened with?
Lignin
122
How does light intensity affect transpiration rate?
The brighter the light, the greater the transpiration rate
123
Why does the rate of transpiration decrease in the dark? [3]
1. Stomata close as it gets dark
2. Photosynthesis can't happen in the dark so they don't need to open to let in CO₂
3. When the stomata are closed, very little water can escape
124
How does temperature affect transpiration rate?
The warmer it is, the faster the transpiration rate
125
Why does transpiration happen faster in warmer temperatures? [2]
1. The water particles have more energy
2. So they evaporate and diffuse out of the stomata more quickly
126
How does air flow affect transpiration rate?
The better the air flow, the greater the transpiration rate
127
Why does transpiration happen faster in good air flow? [3]
1. Water vapour is swept away quickly
2. This maintains a low concentration of water in the air outside the leaf
3. Diffusion then happens quickly, from an area of high conc. to an area of low conc.
128
How does humidity affect transpiration rate?
The drier the air, the faster the transpiration rate
129
Why does transpiration happen faster in dry conditions? [2]
1. There is minimal water in the air
2. So diffusion happens quickly, from an area of high conc. to an area of low conc.
130
What opens and closes the stomata?
Guard cells
131
# Guard cells
What happens when a plant has lots of water? [3]
1. Guard cells fill with water and go plump and turgid
2. Opens the stomata
3. Gases can be exchanged for photosynthesis
132
# Guard cells
What happens when a plant is short of water? [3]
1. Guard cells lose water and become flaccid
2. Closes the stomata
3. Helps stop too much water vapour escaping
133
How are guard cells adapted to open and close? [2]
1. Thin outer walls
2. Thickened inner walls
134
Why are more stomata found on the lower side of a leaf?
Less water is lost through the stomata because it is shaded and cooler
