Topic 2 - Organisation Flashcards
1
Q
What are the organs that make up the human digestive system and their function ?
A
- salivary glands and the pancreas, produce digestive juices containing enzymes that break down food
- stomach produces Hydrochloric acid to kill bacteria and improve optimum pH for the protease enzyme to work
- small intestine, soluble molecules absorbed into the blood
- liver, produces bile which is stored in the gall bladder which helps the digestion of lipids
- large intestine, absorbs water from undigested food to produce faeces, which then passes out of the body through the rectum and anus
2
Q
What is an enzyme ?
A
A biological catalyst (substance that increases the rate of reaction without being used up) that both break up large molecules and join small ones, protein molecules
3
Q
What is the lock and key hypothesis ?
A
- The shape of the substrate is complementary to the shape of the active site so when they bond it forms an enzyme-substrate complex
- Once bound, the reaction takes place and the products are released from the surface of the enzyme
4
Q
How does temperature affect enzymes ?
A
The rate of reaction increases as temperature goes up to optimum
- above optimum the rate rapidly decreases and eventually stops
- because when temperature becomes too hot the bonds in the structure will break, which changes the shape of the active site so the substrate can no longer fit
Enzyme is said to be denatured and can no longer work
5
Q
How does pH affect enzymes ?
A
- if the pH is too high or low the forces that hold the amino acid chains that make up the protein will be affected
- this changes the shape of the active site so the substrate can no longer fit in
- the enzyme is said to be denatured and can no longer work
6
Q
What are the 3 main enzymes for digestion ?
A
Carbohydrase, protease, lipase
7
Q
What does carbohydrase do and where ?
A
- converts carbohydrates into simple sugars
- for example amylase breaks down starch into maltose
- produces in salivary glands, pancreas’s and small intestine
8
Q
What does protease do and where ?
A
- converts proteins into amino acids
- for example pepsin which is produced in the stomach
- other forms can be found in the pancreas and the small intestine
9
Q
What does lipase do and where ?
A
- converts lipids into fatty acids and glycerol
- produced in the pancreas and small intestine
10
Q
What is the food test for sugars ?
A
- Benedict’s test (turns brick red)
11
Q
What is the food test for starch ?
A
- iodine test (turns blue black)
12
Q
What is the food test for protein ?
A
- biuret test (turns purple)
13
Q
What is the food test for lipids ?
A
Emulsion test (add ethanol which results in a cloudy layer if present)
Or
Sudan III test (red layer forms on top)
14
Q
Where is bile produced and what are its 2 roles ?
A
- produced in the liver, stored in the gall bladder and released into the small intestine
- alkaline, neutralizes the stomach acid because enzymes in the small intestine have a higher optimum pH
- breaks down large drops of fat into smaller ones (emulsifies), larger surface area allows lipase to break down the lipid faster
15
Q
Plan a practical to investigate the effect of pH on an enzyme controlled reaction ?
A
- break down of starch to maltose by amylase
1. Put a drop of iodine in each well of a spotting tile
2. Using a water bath, warm a solution of amylase, starch and a buffer solution (independent variable)
3. At regular points in the experiment, take drops of the solution and place in the wells
4. The starch is no longer present when the iodine solution remains brown
5. The time for this to occur is recorded and the rate is calculated from the equation 1000/time
6. The experiment should then be repeated at different pH values while controlling all other factors such as temperature
16
Q
How is blood pumped around the body ?
A
- double circulatory system
- deoxygenated blood flows into the right atrium and then into the right ventricular which pumps it to the lungs to undergo gaseous exchange
- oxygenated blood flows into the left atrium and then into the left ventricle which pumps oxygenated blood around the body
17
Q
Where is the pacemaker found ?
A
Right attium
18
Q
What does a pacemaker do ?
A
Provides stimulation through small electrical impulses which pass as a wave across the heart muscle, causing it to contract
19
Q
What are the 3 blood vessels ?
A
Arteries
Veins
Capillaries
20
Q
Arteries ?
A
- carry blood away from the heart
- layers of muscle in the walls make them strong
- elastic fibers allow them to stretch
- this helps the vessels withstand the high pressure created by the pumping of the heart
21
Q
A
22
Q
Veins ?
A
- carry blood towards the blood
- the lumen is wide to allow the low blood pressure to flow through
- valves to ensure the blood is going in the right direction
23
Q
Capillaries ?
A
- allow the blood to flow very close to cells to enable substances to move between them
- one cell thick walls create a short diffusion pathway
- permeable walls so substances can move across them
24
Q
How is rate of blood flow calculated?
A
Volume of blood / number of minutes
25
What makes up the gas exchange system and what are their functions
Trachea (the windpipe, air moves through here)
• Intercostal muscles (which contract and relax to ventilate the lungs)
• Bronchi (air from the trachea move into these, lead to each lung)
• Bronchioles (bronchi split into these and air moves in)
• Alveoli (bronchioles lead to the alveoli, air sacs where gaseous exchange occurs)
• Diaphragm (separates the lungs from the digestive organs, moves down causing inhalation)
26
What happens during inhalation ?
1. The ribcage moves up and out and the diaphragm moves down causing the volume of the chest to increase
2. Increased volume results in lower pressure.
3. Air is drawn into the chest as air moves from areas high pressure (the environment) to low pressure (the lungs).
4. The opposite happens when exhaling.
27
What is the process of gas exchange ?
1. Upon inhalation, the alveoli fill with oxygen.
2. The blood in the capillaries surrounding the alveoli is deoxygenated (it has come from the pulmonary artery). It has lots of carbon dioxide as this is a product of respiration.
3. Oxygen diffuses down its concentration gradient into the capillary bloodstream, which has a low concentration of oxygen.
4. Carbon dioxide diffuses down its concentration gradient from the blood to the alveoli
28
How are the alveoli adapted to their function ?
• They are very small and arranged in clusters, creating a large surface area for diffusion to take place over
• The capillaries provide a large blood supply, maintaining the concentration gradient
• The walls of the alveoll are very thin, meaning there is a short diffusion pathway
29
How can you calculate breathing rate ?
Number of breaths / number of minutes
30
What substances is the blood made up of ?
1. Plasma
2. Red blood cells
3. White blood cells
4. Platelets
31
What is plasma and its function ?
1. Plasma
• This is liquid that carries the components in the blood: red blood cells, white blood cells, platelets, glucose, amino acids, carbon dioxide, urea, hormones, proteins, antibodies and antitoxins
32
What are red blood cells and their function ?
2. Red blood cells
• They carry oxygen molecules from the lungs to all the cells in the body
• Their bioconcave disc shape provides a large surface area
• They have no nucleus allowing more room to carry oxygen
• They contain the red pigment haemoglobin, which binds to oxygen and forms oxyhaemoglobin
33
What are white blood cells and their function ?
3. White blood cells
• They are a part of the immune system, which is the body's defence against pathogens (microorganisms that can produce disease)
• They have a nucleus
• There are a number of types:
• 1- Those that produce antibodies (small proteins that clump them together) against microorganisms
• 2- Those that engulf and digest pathogens
• 3- Those that produce antitoxins to neutralise toxins (poisons)
produced by microorganisms
34
What are platelets and their function ?
4. Platelets
• They help the blood clot form at the site of a wound
The clot dries and hardens to form a scab, which allows new skin to grow underneath while preventing microorganisms from entering
• Small fragments of cells
No nucleus
• Without them, cuts would result in excessive bleeding and bruising
35
What is coronary heart disease ?
When the coronary arteries that provide blood to the heart become blocked with the build up of fatty material. This results in less blood flowing to the heart, reducing its oxygen supply which can lead to a heart attack
36
What are 2 solutions for coronary heart disease ?
Stents and statins
37
What are stents and what are some pros and cons ?
- metal mesh tubes inserted in arteries that keep the arteries open to allow blood to flow through
Pros : effective in lowering the risk of a heart attack, quick recovery time from surgery
Cons : risk of a heart attack during the procedure, or that infection could occur following it, chance blood clots can form near the stent
38
What are statins and give some pros and cons ?
- drugs that decrease the levels of LDL cholesterol which could otherwise lead to coronary heart disease
Pros : reduce the risk of strokes coronary heart disease and heart attacks, increase levels of HDL (good) cholesterol
Cons : need to be taken continuously (inconvenient), can produce side effects, may not have an immediate effect
39
What are some solutions for faulty valves ?
Replacing it with a biological valve (pig)
- works very well
- but only lasts 12-15 years
Replacing it with a mechanical valve
- lasts for a long time
- but constant need for medication to stop blood clots
40
What is a solution for heart failure and give pros / cons ?
Heart transplant :
- requires a donor so an artificial one may be used
Pros : less likely to be rejected by the immune system
Cons : body exposed to infection, mechanical parts could wear out and the motor could fail, blood clots could form leading to strokes
- to prevent this drugs are taken to thin blood
41
What is the solution to extreme blood loss ?
Artificial blood :
- salt solution that can keep the patient alive even if they lose 2/3 of their red blood cells
Positives : means the body has more time to produce new blood cells
Negatives: can only be used for a short period of time until a blood transfusion has to take place
42
What is health ?
A state of physical, mental and social wellbeing
43
What are the 2 categories of disease ?
1. Communicable diseases- these are infectious as they are caused by pathogens
(bacteria, viruses, fungi), and are passed on from one person to another. An
example is the flu.
2. Non-communicable diseases- these are not passed on from person to person. An
example is heart disease.
44
What are factors that affect health ?
- disease
- diet
- stress
- life situations
45
How does diet affect health ?
Diet: Eating too little or too much food, not enough nutrients or the wrong type of food prevents you from having a good, balanced diet. This can have a big effect on mental and physical health, causing issues such as type 2 diabetes or obesity.
46
How does stress affect health ?
• Stress: Physical and mental stress places strain on our bodies. This can lead to problems such as heart disease, cancers and mental illnesses.
47
How do life situations affect health
• Life situations: Where you live, your financial status, your ethnic group, your access to medical care and the levels of hygiene in your area are some examples of factors which may affect your physical and mental health. They can lead to communicable diseases such as diarrhoea and malaria, or non-communicable diseases like heart disease.
48
What are risk factors of cardiovascular disease ?
• Diet containing lots of LDL (bad) cholesterol results in arteries becoming blocked, increasing blood pressure
• Smoking damages the walls of arteries
• Exercise lowers blood pressure, reducing strain on the heart
49
What are risk factors of type 2 diabetes?
Type 2 diabetes
• Obesity affects the body's metabolism- fat molecules are released into the blood which can affect the cells uptake of sugar
50
What are risk factors of liver and brain function problems?
- alcohol causes fatty liver, which can cause liver failure
- alcohol can damage nerve cells in the brain
51
What are the risk factors of lung disease and lung cancer ?
- smoking damages cells in the lining of the lungs
52
What are the risk factors of pregnancy?
- smoking and alcohol can cause many damaging effects on the unborn child
53
What are risk factors of cancer ?
Carcinogens such as ionizing radiation
54
What are the 2 types of tumor ?
1. Benign- growths of cells contained in one place, usually within a membrane
• Not cancerous
• It grows until there is no more room
• It does not invade other tissues
• If it causes pressure or damage to an organ, it can be dangerous
2. Malignant- the tumour grows and spreads to other tissues
• Cancerous
• The tumour may split up, resulting in cells being carried in the bloodstream or lymphatic system
• They can travel to and stay in another organ, potentially causing secondary tumours
• The cancer cells divide more rapidly and have a longer life span in comparison to normal cells
55
What are some lifestyle risk factors for cancer ?
• Smoking (lung, mouth, bowel, stomach and cervical cancer)
• Obesity (bowel, liver and kidney cancer)
• UV light (skin cancer)
• Viral infection (liver cancer from hepatitis B and C, cervical cancer from HPV)
Genetic risk factors for cancer:
• You can inherit certain genes which increase the likelihood of getting cancer
56
What are the features of the epidermal tissue and its function ?
- covers the whole plant
- covered by the waxy cuticle
- helps reduce water loss by evaporation as the waxy cuticle prevents water from moving out
57
What are the features of the palisade mesophyll tissue and what’s its function ?
- found underneath the epidermal tissue
- lots of chloroplasts
- this means that photosynthesis can happen rapidly, positioned at the top of the leaf so they receive lots of light
58
What are the features of the spongy mesophyll tissue and what’s its function ?
- Found underneath the palisade mesophyll
- has lots of air spaces
- allows gases to diffuse in and out of cells
59
What are the features of the xylem and what’s its function ?
- found in the roots, stems and leaves
- made up of dead cells joined together
- allows the movement of water and mineral ions from the roots to the stem and leaves where it evaporates and leaves the plant (transpiration stream)
- strengthen with lignin but this has some holes in it along the tube called bordered pits
- lignin makes it strong and waterproof so no water will leave except the bordered pits which allow minerals to go to specific places in the plant
60
What are the features of the phloem and its function ?
- found in the roots, stems and leaves
- elongated cells with holes in the cell walls (sieve plates)
- food substances can be moved in both directions from the leaves where they are made for use or from storage to parts of the plant that need it (translocation)
- many organelles are removed so cell sap can move through
61
What are the features of the meristematic tissue and what’s it function ?
- found at the tips of roots and shoots
- able to differentiate into different types of plant cells
- allows plant to grow
62
What is translocation ?
The movement of food substances made in the the leaves up or down the phloem
63
What is transpiration?
The loss of water of water vapor from the leaves and stems of a plant
64
How does increased temperature affect the rate of transpiration ?
The molecules move faster, resulting in evaporation happening at a faster rate and therefore the rate of transpiration increases.
The rate of photosynthesis increases, meaning more stomata are open for gaseous exchange, so more water evaporates and the rate of transpiration increases.
65
How does increased relative humidity affect the rate of transpiration?
If the relative humidity is high, then there will be a reduced concentration gradient between the concentrations of water vapour inside and outside the leaf, resulting in a slower rate of diffusion. This will decrease the rate of transpiration.
66
How does increased air movement affect the rate of transpiration?
If more air is moving away from the leaf due to it being blown away, then the concentration of water vapour surrounding the leaf will be lower, This will mean there will be a steeper concentration gradient resulting in diffusion happening faster.
This will increase the rate of transpiration.
67
How does increased light intensity affect the rate of transpiration?
This leads to an increased rate of photosynthesis, so more stomata open to allow gaseous exchange to occur. This means more water can evaporate, leading to an increased rate of transpiration.
68
What does a potometer work ?
- measures the uptake of water of a plant
- involves placing a plant in a tube of water and measuring the distance travelled by a bubble
69
What do guard cells do
• close and open stomata
• They are kidney shaped
• They have thin outer walls and thick inner walls
• When lots of water is available to the plant, the cells fill and change shape, opening stomata (they are also light sensitive)
• This allows gases to be exchanged and more water to leave the plant via evaporation
• More stomata are found on the bottom of the leaf, allowing gases to be exchanged whilst minimising water loss by evaporation as the lower surface is shaded and cooler.
