Topic 2 - Organisation Flashcards
1
Q
What is a tissue
A
A group of similar cells that work together to carry out a particular function
2
Q
What are muscular tissues functions in mammals
A
They contract to move whatever it’s attached to
3
Q
What are glandular tissues functions in mammals
A
They secrete chemicals like enzymes and hormones
4
Q
What are epithelial cells in mammals
A
They cover some parts of the body, like inside and outside of the stomahc
5
Q
What do muscular tissues do in the stomach
A
Move the stomach wall to churn up the food
6
Q
What do glandular tissues do in the stomach
A
Make digestive juices to digest food
7
Q
What organs is the digestive system made up from
A
Mouth, Oesophagus, stomach, small intestine, large intestine, liver and glands
8
Q
What does the stomach do in the digestive system
A
-Pummels food with muscular walls
-Produces the protease enzyme pepsin
-Produces hydrochloric to give the right pH for the protease to work and it kills bacteria
9
Q
What does the liver do in the digestive system
A
Produces bile which emulsifies fat and neutralises stomach acid
10
Q
What does the small intestine do in the digestive system
A
-Absorbs soluble food molecules into the blood
-Produces lipase, protease and amylase
11
Q
What does the large intestine do in the digestive system
A
Absorbs water from undigested food leaving faeces
12
Q
What are enzymes
A
Large proteins that are made up of chains of amino acids that act as biological catalysts speeding up the useful chemical reactions in our body
13
Q
What is the lock and key hypothesis
A
Each enzyme has an active site of a specific shape meaning usually only one type of substrate can fit into the active site, so enzymes are highly specific. When the substrate fits into the active site the enzymes catalyses the reaction and the products are then released. The active remains unchanged so it can be used again.
14
Q
How does temperature affect the rate of an enzyme catalysed reaction
A
A higher temperature increases the rate at first, but if it gets too hot some of the bonds holding the enzyme together break changing the shape of the active site so the substrate won’t fit anymore. This is where an enzyme is denatured.
15
Q
What is optimum temperature for enzymes
A
The temperature at which enzymes work best at
16
Q
How does pH affect enzymes
A
If the pH is too high or too low it inferred with the bonds holding the enzymes together so the active site shape changes and the enzyme is denatured
17
Q
What is optimum pH and what is it generally
A
The optimum pH of an enzyme reaction is the pH level an enzyme works best at and it’s usually pH 7
18
Q
Give an example of an enzyme that doesn’t have an optimum pH of 7
A
Pepsin is an enzyme used to break down proteins in the stomach but it works best at a pH of 2, in acidic conditions.
19
Q
Outline how to investigate the effect of pH on enzyme activity
A
- Put a drop of iodine into each well of a spotting tile
- Put a beaker of water on a bunsen burner and tripod and heat until it is 35° using a thermometer and try keep the temperature constant
- Use a syringe to add 1cm of amylase solution and 1cm of buffer solution with a pH of 5 to a boiling tube, then using test tube holders put the tube into the beaker of water and wait five minutes
- Using a different syringe put 5cm of starch solution to the boiling tube
- Mix the contents of the boiling tube and start a stop watch
- Use continuous sampling to record how long it takes for the amylase to break down all of the starch by dropping the solution into a well using a pipette every 30 seconds and when the iodine remains brown/orange the starch is broken down
- Repeat with buffer solutions of different pHs to see how quickly the starch is broken down
- Remember to control any variables each time (e.g. concentration and volume of amylase to make it a fair test.
20
Q
What is the formula for rate of reaction
A
Rate = 1000/time
21
Q
How to calculate the rate of reaction of an experiment which measures how much something changes over time
A
you calculate it by diving the amount it has changed by the time taken
22
Q
What product do digested proteins make, what enzyme breaks them down and where
A
They make amino acids when broken down by protease in either the stomach, small intestine and pancreas
23
Q
What product do digested carbohydrates/starch make, what enzyme breaks them down and where
A
They make sugar/glucose when they are broken down by carbohydrase (e.g amylase) in either mouth, pancreas, small intestine.
24
Q
What product do digested lipids make, what enzyme breaks them down and where
A
They make glycerol and fatty acids when lipase breaks them down in the pancreas and small intestine
25
What is biles job in the digestion system
-As it is an alkaline it neutralises acid and makes the conditions in the small intestine alkaline so the enzymes can work properly
-Emulsifies fat so it is broken down into small drops so the surface area is larger and it is easier for lipase to work on so digestion is faster.
26
What is the job of salivary glands in the digestive system
These produce amylase enzyme in the saliva
27
What is the job of the gall bladder
It stores bile before it’s released into the small intestine
28
What is the job of the pancreas in the digestive system
Produces protease, amylase and lipase and releases them into the small intestine
29
How do you start each food test before adding the solutions (digestive system)
-Get a piece of food and break it up using a pestle and mortar
-Transfer it into a beaker and add some distilled water
-Give the mixture a good stir with a glass rod to dissolve some of the food
-Filter it using a funnel lined with filter paper to get rid of the solid bits of food
30
How to test for sugars
-Put a 5cm of a food sample into a test tube
-Prepare a water bath so that’s so that it’s set to 75°C
-Add some Benedict’s solution the test tube using a pipette
-Place the test tube in the water bath using a test tube holder and leave it in there for 5 minutes and make sure the tube is pointing away for you.
-If it contains sugar it will turn from blue to yellow/red depending how much sugar there is
31
How to test for starch
-Transfer 5cm of your food sample to a test tube
-Then add a few drops of iodine solution and gently shake the test tube to mix the contents
-If it contains starch it will change from browny-orange to blue/black
32
How to test for proteins
-Transfer 2cm of your food sample to a test tube
-Add 2cm of biuret solution to the sample and max by gently shaking it
-If the sample contains protein, the solution will change from blue to purple
33
How to test for lipids
-Prepare a sample of the food you’re testing and transfer 5cm
-Use pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake the tube
-Sudan III stain solution stains lipids so if the sample contains lipids the mixture will separate out into two layers and the top will be bright red. If no lipids no separate will form.
34
What happens to air when you breathe (outline)
It goes in through the trachea this splits two tubes called bronchi one going to each lung
The bronchi split progressively smaller tubes tubes called bronchioles
The bronchioles finally end at small bags called alveoli where the gas exchange takes place
35
How do the alveoli carry out gas exchange in the body
-They are surrounded by a network of blood capillaries and the blood passing through has just returned to the lungs from the rest of the body so it contains lots of CO2 and very little oxygen.
-The oxygen diffuses out of the alveoli into the blood and the CO2 diffuses from the blood into the alveoli to be breathed out
36
What happens to oxygen and carbon after gas exchange
When the blood reaches body cells the oxygen diffuses out from the red blood cells into the body cells
At the same time carbon dioxide diffuses out of the body cells into the blood where it’s the n carried back to the lungs
37
Outline the double circulatory system system
-The right ventricle pumps deoxygenated blood to the lungs to take in oxygen the blood the returns to the heart
-The left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up it’s oxygen at the body cells and the deoxygenated blood returns to heart to be pumped out to the lungs again.
38
What do valves do in the heart
They make sure blood flows in the right direction - they prevent it flowing backwards.
39
How does the heart use its four chambers to pump blood around
-Blood flows into the two atria from the vena cava and pulmonary veins
-Then they go down into the ventricles which contract forcing the blood into pulmonary artery aorta , and out of the heart
-They flow to organs through the arteries and return through veins
-The atria fill again and the whole cycle
40
How does the heart receive its own supply of oxygenated blood
Coronary arteries branch off the aorta and surround the heart, making sure that it gets all the oxygenated blood it needs
41
How is heart rate controlled
By a group of cells in the right atrium that act as pacemaker
The cells produce a small electric impulse which spreads to the surrounding muscle cells causing them to contract
42
How do artificial pacemakers works
They control heartbeat if the natural pacemaker cells don’t work properly and it’s a little device implanted under the skin and has a wire going to the heart it produces an electric to keep heart beating regularly
43
Outline the function and properties of arteries
-They carry the blood away from the heart
-The heart pumps the blood out at high pressure so the artery walls are strong and elastic
-Thick walls compared to the size of the hole down the middle
-They contain thin layer of muscle to make strong and elastic fibres allow them to stretch and spring
44
Outline the function and properties of capillaries
-Involved in the exchange of materials at the tissues
-Arteries branch into capillaries which carry blood close to every cell in the body to exchange substances with them
-*Permeable walls so substances can diffuse in and out*
-They supply food and oxygen and take away waste like CO2
-Walls are only one cell thick increasing they rate of diffusion by decreasing the distance over which it occurs
45
Outline the function and properties of veins
-Capillaries eventually join up to form veins and the blood is at lower pressure so the walls don’t need to be as thick
-They have a bigger lumen than arteries to help the blood flow despite the lower pressure
-Have valves to keep the blood flowing in the right direction
46
How to calculate the rate of blood flow
Volume of blood / number of minutes
47
What is the job of red blood cells
To carry oxygen from the lungs to all the cells in the body
48
Properties of red blood cells
-Shaped like a biconcave disc so they have a large surface for absorbing oxygen
-Don’t have a nucleus allows them to carry more oxygen
-They contain a red pigment called haemoglobin
-In the lungs haemoglobin binds to oxygen to become oxyhaemoglobin and in body tissues the opposite happens where oxyhaemoglobin splits into oxygen and haemoglobin to release oxygen into the cells
49
What do white blood cells do and their properties
-Some can change shape to gobble up unwelcome microorganisms, in a process called phagocytosis
-Others produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms
-Unlike red blood cells they do have a nucleus
50
What do platelets do and what properties do
-They are small fragments of cells and they have no nucleus
-They help the blood clot at a wound to stop all of your blood from pouring out and to stop microorganisms from getting in
-Lack of platelets can cause excessive bleeding and bruising
51
What is plasma in blood
It is a pale straw coloured liquid that carries:
-Red and white blood cells and platelets
-Nutrients like glucose and amino acids
-carbon dioxide
-Urea from the liver to the kidneys
-Hormones
-Proteins
-Antibodies and antitoxins
52
What is coronary heart disease
-When the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up causing the arteries to become narrow so blood flow is restricted and there’s a lack of oxygen to the heart muscle can result in a heart attack
53
What are stents
Tubes that are inserted inside arteries. They keep them open making sure blood can pass through to the heart muscles. This keeps the person’s heart beating
54
What are advantages to stents
-Lower the risk of a heart attack in people with CHD and are effective for a long time with the surgery’s recovery time being very quick
55
What are the disadvantages of stents
Risk of complications during the surgery and a risk of infection from it
Also the risk of patients developing a blood clot near the stent
56
What do statins do
Too much of LDL cholesterol can cause health problems and having too much in your blood stream can cause fatty deposits to form inside arteries leading to CHD but statins are drugs that reduce the amount of this cholesterol present in the blood stream slowing down the rate of fatty deposits forming
57
Advantages of statins
-Reduce the risk of heart attacks and CHD
-can increase the beneficial cholesterol in your bloodstream which remove the bad cholesterol from your bloodstream
-May also help prevent some other diseases
58
Disadvantages of statins
-A long-term drug that must be taken regularly there’s a risk someone could forget to take them
-Can cause negative side effects (e.g headaches or more serious ones like kidney failure)
-Effect isn’t instant it can take a while to kick in
59
Outline artificial hearts
They are mechanical devices that pump blood for a person whose own heart has failed and are usually a temporary fix, to keep a person alive until a donor heart can be found or to help a person recover by allowing the heart to rest and heal however some can be permanent
60
Advantages of artificial hearts
Less likely to be rejected by the body’s immune system than a donor heart as they’re made from metals or plastics so the body doesn’t recognise them as foreign and attack in the same way as it does with living tissue
61
Disadvantages of artificial hearts
-Surgery to fit them can lead to bleeding and infection and they don’t work as well as a healthy natural heart as parts could wear out or the electrical motor could fail.
-Blood doesn’t flow through the artificial heart as smoothly which can cause blood clots and lead to strokes and the patients has to take drugs to thin their blood so this doesn’t happen which can cause problems with bleeding if they’re in an accident.
62
Why would a valve replacement be needed and what do they do
-Valves can become damaged or weakened by heart attack, infection or old age
-The damage may cause the valve tissue to stiffen so it won’t open properly and it make become leaky allowing blood to flow in both directions so it doesn’t circulate as well
-Severe damage can be treated by replacing the valve from other humans or mammals (biological valves) or man-made valves (mechanical
63
Advantage and disadvantage of artificial valve replacements
-Less dramatic than heart transplant surgery
-Still a major surgery and can be a problem with blood clots
64
What is it and when would artificial blood be needed
-When someone loses a lot of blood their heart can still pump remaining red blood cells wound as long as the volume of their blood can still be topped up
-Blood substitute (e.g. a salt solution) is used to replace the lost volume as it’s safe and can keep people alive even if they lose 2/3 of their red blood cells and it may give the patient enough time to produce new blood cells if not they will need a transfusion.
65
What are communicable diseases
Diseases that can be spread from person to person or between animals and people
66
What are non-communicable diseases
Diseases that cannot spread between people or between animals and people. They generally last for a long time and get worse slowly.
67
What happens to people who have problems with their immune system
They have an increased chance of suffering from communicable diseases as their body is less likely to be able to defend itself against the pathogen that causes the disease
68
What can happen to immune system when infected by a pathogen
Allergic reactions can be triggered
69
What can cause mental health issues
-When someone is suffering from severe physical health problems
70
What factors can affect your health (3)
-Diet
-Stress
-Life situation (e.g. if you have easy access to medicines)
71
What are risk factors
Things linked to an increase in the likelihood that a person will develop a certain disease during their lifetime
72
What can risk factors be effected by
-A persons lifestyle (e.g. exercise) and presence of certain substances in an environment or in your body
73
How is smoking a risk factor
It is proven to cause cardiovascular disease, lung disease and lung cancer and it damages the walls of arteries and the cells in the lining of the lungs.
74
How is obesity a risk factor
Can directly cause type 2 diabetes by making the body less sensitive or resistant to insulin meaning that it struggles to control the concentration of glucose in the blood
75
How is alcohol a risk factor
It has been shown to cause liver disease and can effect brain function and can damage the nerve cells in the brain, causing the brain to lose volume.
76
How is smoking a risk factor
When pregnant it can cause lots of health problems for the unborn baby.
77
How is exposure to certain substances or radiation a risk factors
Cancer can be directly caused directly by it
78
What is a tumour
A controlled growth and division in cells
79
What are benign tumours
Where the tumour grows till there’s no more room and the tumour stays in one place rather than invading other tissues in the body
80
What are malignant tumours
Where the tumour grows and spread to neighbouring healthy tissues. Cells can break off and spread to other parts of the body by travelling in the bloodstream. The malignant cells then invade healthy tissues elsewhere in the body and form secondary tumours. They are dangerous and can be fatal.
81
How are viral infections a risk factor
Infection with some viruses have been shown to increase the chances of developing certain types of cancer. For example, infection with hepatitis B and C with these viruses somethings depends on lifestyle - they can be spread between people through unprotected sex or sharing needles
82
How can genes be risk factors
Sometimes you can inherit fault genes that make people more susceptible to cancer (e.g. mutations in the BRCA genes have been linked to an increased likelihood of developing breast and ovarian camcer
83
What does epidermal tissue do in plants
It covers the whole plant
84
What does palisade mesophyll tissue do in plants
The part of the leaf where most photosynthesis happens
85
What does spongy mesophyll tissue do in plants
This is also in the leaf and contains big air spaces to allow gases to diffuse in and out of cells.
86
What do xylem and phloem do in plants
They transport things like water, mineral ions and food around the plant
87
What do meristem tissues do in plants
Found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cell allowing the plant to grow
88
What does epidermal tissue do in leaves
Covered with a waxy cuticle to help reduce water loss by evaporation
89
What does the upper epidermis do in leaves
It’s transparent so that light can pass through it to the palisade layer
90
What does palisade layer do in leaves
It has lots of chloroplasts this means that they’re near the top of the leaf where they can get the most light
91
What does the xylem and phloem do in leaves
Form a network of vascular bundles, which deliver water and other nutrients to the entire leaf and take away the glucose produced by photosynthesis and they help support the structure
92
What are tissues adapted to do in leaves
For efficient gas exchange (e.g. the lower epidermis is full of little holes called stomata which let CO2 diffuse directly into the leaf. The opening and closing of stomata is controlled by guard cells in response to environmental conditions. The air spaces in the spongy mesophyll tissue increase the rate of diffusion of gases
93
What do phloem do (translocation)
-They’re made of columns of elongated living cells with small pores in the end walls to allow cell sap to flow through
-Transport food substances made in the leaves to the rest of the plant for immediate use or storages
-The transport goes in both directions
-This process is called translocation
94
What do xylem do in transpiration
-Made of dead cells joined end to end with no end walls between them and a hole down the middle. They’re strengthened with a material called lignin
-They carry water and mineral ions from the roots to the stem and leaves
-The movement of water from the roots, through the xylem and out of the leaves is called the transpiration stream
95
How does transpiration take place
-Caused by evaporation and diffusion of water from a plants surface. Most transpiration happens at the leaves
-This evaporation creates a slightly shortage of water in the leaf, and so more water is drawn up from the rest of the plant through the xylem vessels to replace it.
-This means more water is drawn up from the roots, and so there’s a constant transpiration stream of water through the plant
96
How does light intensity affect transpiration
The brighter the light the greater the transpiration rate. Stomata close as it gets darker and photosynthesis can’t happen in the dark, so they don’t need to be open to let CO2 in. When the stomata are closed, very little water can escape.
97
How does temperature affect transpiration
The warmer it is, the faster transpiration happens. When it’s warm the water particles have more energy to evaporate and diffuse out of the stomata.
98
How does air flow affect transpiration
The better the air flow around a leaf the greater the transpiration rate. If air flow around a leaf is poor the water vapour just surrounds the leaf and doesn’t move away. So there’s a high concentration of water particles outside the leaf as well as inside it, so maintaining a low concentration of water in the air outside the leaf. Diffusion then happens quickly, from an area of higher concentration to an area of lower concentration
99
How does humidity affect transpiration
The drier the air around a leaf, the faster transpiration happens. This is like what happens with air flow. If the air is humid there’s a lot of water in it already, so there’s not much of a difference between the inside and the outside of the leaf. Diffusion happens fastest if there’s a really high concentration in one place, and a really low concentration in the other.
100
How can the rate of transpiration be measured and why
-By measuring the uptake of water by a plant. This is because you can assume that water uptake by the plant is directly related to water loss by the leaves.
-Set up the apparatus as in the diagram then record the starting position of the air bubble. Start a stopwatch and record the distance moved by the bubble per unit time, and record the distance moved by the bubble per unit time
101
Where are stomata found
Mostly on the undersides of leaves than on the top as the lower surface is shaded and cooler - so less water is lost through the stomata than if they were on the upper surface.
102
How do guard cells work
-Kidney shape which opens and closes the stomata in a leaf
-When the plant has lots of water the guard cells fill with it and go plump and turgid. This makes the stomata open so gases dan be exchanged for photosynthesis
-When the plant is short of water, the guard cells lose water and become flaccid, making the stomata close. This helps stop too much water vapour escaping.
-Thin outer walls and thickened inner walls make the opening and closing work
-They’re also sensitive to light and close at night to save water without losing out on photosynthesis
