Organisation Flashcards
1
Q
What is a enzyme?
A
a biological catalyst which increases the speed of a reaction, without being changed or used up in the reaction
2
Q
What are enzymes made of?
A
Large proteins and proteins are made up of chains of amino acids
3
Q
Why do enzymes have special shapes?
A
- every enzyme has an active site with a unique shape that fits onto a substrate
- they usually only catalyse one specific reaction because for an enzyme to work the substrate has to fit into its active site
- if the substrate doesn’t match the active site then the reaction wont be catalysed
4
Q
What two things affect enzymes ?
A
temperature - changes the rate of the reaction
- a high temp increases the rate but if it gets too hot, the bonds holding the enzyme together will break, changing the shape of the active site and the enzyme is denatured so the substrate wont fit anymore
- enzymes have a optimum temp they work best at
pH
- if it is too high or too low the bonds holding the enzyme together will break, changing the shape of the active site and denaturing the enzyme
- enzymes have a optimum pH they work best at, its USUALLY pH 7 but not always (e.g pepsin works best at pH 2 in the acid conditions of the stomach)
5
Q
What are carbohydrates broken down into and by what enzyme?
A
Starch (carbohydrate) is broken down by amylase into simple sugars e.g maltose
6
Q
Where is amylase made?
A
- salivary glands
- pancreas
- small intestine
7
Q
What are proteins broken down into and by what enzyme?
A
proteins are broken down by protease into amino acids
8
Q
Where is protease made?
A
- the stomach (called pepsin there)
- the pancreas
- the small intestine
9
Q
What are lipids broken down into and by what enzyme?
A
lipids (fats and oils) are broken down by lipase into glycerol and fatty acids
10
Q
Where is lipase made?
A
- the pancreas
- the small intestine
11
Q
What are the two jobs of bile?
A
neutralises the stomach acid - the hydrochloric acid in the stomach makes the pH too acidic for enzymes to work so bile which is alkaline neutralises the acid and makes conditions alkaline.
It emulsifies fats - breaks fat into tiny droplets to give a bigger surface area for the enzyme lipase to work on to make digestion faster.
12
Q
where is bile produced and stored?
A
its produced in the liver and stored in the gall bladder before its released into the small intestine
13
Q
What is the journey of digesting food?
A
- (food enters body through the mouth)
- teeth break down food into smaller pieces and saliva produced by salivary glands contains amylase begins breaking down carbohydrates
- tongue pushes food to the back of the mouth and it travels down the oesophagus
- the stomach pummels food with its muscular walls and it also produces hydrochloric acid to kill bacteria and so its the right pH for the protease enzyme to work
- pancreas releases enzymes into the small intestine and the liver produces bile
- then it goes to the small intestine that produces amylase, protease, lipase to complete digestion and the nutrients from the digested food is absorbed out of the digestive system and into the blood
- the large intestine absorbs excess water from the food
- the rectum stores faeces that is then removed through the anus (egestion)
14
Q
How do you carry out the benedict’s test? (biscuits, cereal and bread)
A
- prepare a food sample and transfer 5cm³ into a test tube
- prepare a water bath set to 75°
- add about 10 drops of benedict’s solution to the test tube using a pipette
- place the test tube in the water bath using a test tube holder and leave it there for 5 minutes
- if the food sample contains reducing sugar the result should be the solution should change from the normal blue colour to green, yellow or brick red (depending on how much sugar)
15
Q
How do you carry out the iodine solution test? (pasta, rice, potatos)
A
- prepare a food sample and transfer 5cm³ into a test tube
- add a few drops of iodine solution and gently shake to mix
- if the sample contains starch the result of the colour of the solution should change from browny-orange to black or blue-black.
16
Q
How do you carry out the biruet test? (meat and cheese)
A
- prepare a food sample and transfer 2cm³ to a test tube
- add 2cm³ of biruet solution to the sample and gently shake to mix it
- if the sample contains protein the result should be the solution changes colour from blue to purple
17
Q
How do you carry out the Sudan III test? (olive oil, margarine, milk)
A
- prepare a food sample and transfer 5cm³ into a test tube
- use a pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake the tube
- Sudan III stains lipids so the result if the sample contains lipids is the mixture will separate into two layers, the top layer will be bright red
18
Q
What is the thorax?
A
the top part of your body (separated by the lower part by the diaphragm)
19
Q
Describe the pathway of the air you breath in travels?
A
- air enters nose or mouth
- goes through the trachea
- this divides into two bronchi going to each lung
- bronchi split off into smaller stubes called bronchioles
- these end in tiny air sacks called alveoli where gas exchange occurs
20
Q
How do alveoli carry out gas exchange?
A
- the blood capillary passing next to the alveoli contains lots of carbon dioxide
- oxygen diffuses out of the alveolus into the blood from a high concentration to a low concentration
- carbon dioxide diffuses out of the blood into the alveolus from a high concentration to a low concentration to be breathed out
21
Q
How does gas exchange happen from the blood into body cells?
A
- when the blood reaches body cells oxygen is released from the red blood cells and diffuses into body cells from a high concentration to a low concentration
- at the same time carbon dioxide diffuses out of body cells and into red blood cells from a high concentration to a low concentration
- its then carried back to the lungs
22
Q
Whats the formula for breathing rate?
A
breaths per minute = number of breaths/number of minutes
23
Q
What are the two circuits of the double circulatory system?
A
24
Q
What is the function of the valves in the heart?
A
they prevent blood from flowing backwards
25
How many chambers are in the heart?
4 chambers - right atrium, right ventricle, left atrium, left ventricle
26
Describe the pathway blood flows through the heart?
- deoxygenated blood flows into the right atrium through the vena cava
- the right atrium contracts pushing blood to the right ventricle
- the right ventricle contacts forcing blood into the pulmonary artery which carries it to the lungs for gas exchange
- oxygenated blood returns into the left atrium through the pulmonary vein
- the left atrium contracts pushing blood to the left ventricle
- the left ventricle contracts powerfully pushing blood through the aorta which pumps oxygenated blood to the rest of the body
27
What are coronary arteries for?
they branch of the aorta and surround the heart making sure it gets its own supply of oxygenated blood
28
What is the pacemaker and where is it located in the heart?
- your resting heart rate is controlled by a group of cells in the right atrium wall that act as a pacemaker
- these cells produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract
29
What is a artificial pacemaker?
- used to control heartbeat if the natural pacemaker doesn't work
- its a little device implanted under the skin with a wire going to the heart, it produces an electrical current to keep the heart beating regularly
30
What are the jobs of arteries, capillaries and veins?
arteries - carry blood away from the heart
capillaries - involved in exchange of materials
veins - carry blood to the heart
31
What are the characteristics of the arteries?
- walls are strong and elastic to pump blood at a high pressure
- walls are thick compared to the size of the lumen
- contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch
32
What are the characteristics of the capillaries?
- walls are 1 cell thick to increase the rate of diffusion by decreasing the distance
- very small lumen
- permeable walls for diffusion
- supply food and oxygen and take away waste like carbon dioxide
33
What are the characteristics of the veins?
- walls are less thick than arteries because blood is at a lower pressure
- bigger lumen than arteries to help blood flow because of low blood pressure
- they have valves to prevent backflow
34
whats the formula to calculate the rate of blood flow?
volume of blood/number of minutes
35
What is the function of red blood cells?
- carry oxygen from the lungs to all the body cells
- they have a biconcave shape for a larger surface area to absorb more oxygen
- no nucleus to allow more room for oxygen
- contain a red pigment called haemoglobin
36
What is the function of white blood cells?
- some engulf and digest pathogens in a process called phagocytosis
- others produce antibodies to fight/bind to pathogens and antitoxins to neutralise any toxins produced by them
- they have a nucleus
37
What is the function of platelets?
- they help the blood clot at a wound to stop blood pouring out and microorganisms coming in
- they are small fragments of cells
- they have no nucleus
- lack of them causes excessive bleeding and bruising
38
What is the function of plasma?
- a liquid that carries everything in the blood like red + white blood cells, platelets, nutrients like glucose and amino acids, carbon dioxide, urea, hormones, proteins, antibodies and antitoxins
39
What is coronary heart disease?
- coronary arteries that supply blood to the heart get blocked by layer of fatty material building up
- causing arteries to become narrow so blood flow is restricted and there's a lack of oxygen which can cause a heart attack
40
How can coronary heart disease be treated?
stents
- they are tubes inserted into arteries
- they keep them open letting blood pass through to the heart to keep the heart beating
- they are effective for a long time and the recovery time from the surgery is quick
- however, there is risk of infection during surgery and risk of patients developing a blood clot near the stent (thrombosis)
41
What do stains do?
they are drugs that can reduce the amount of bad cholesterol present in the blood stream, this slows down the rate of fatty deposits forming in the arteries
42
What are the advantages and disadvantages of stains?
advantages
- by reducing the amount of bad cholesterol in the blood stains reduce the risk of coronary heart disease, strokes and heart attacks
- they can increase the amount of a beneficial type of cholesterol known as HDL cholesterol in the blood which can remove the bad cholesterol
disadvantages
- they must be taken regularly so there's a risk someone might forget to take them
- can sometimes cause negative side effects like headaches, or some can be serious like kidney failure, liver damage, memory loss
43
How can heart failure be treated?
- doctors may fit an artificial hearts, they are mechanical devices that pump blood for a person whose own heart has failed
- they're usually only used as 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
- in some cases they can be used as a permanent fix, reducing the need for donor hearts
44
What are the advantages and disadvantages of an artificial heart?
advantages
- they are less likely to be rejected by the body's immune system than a donor heart because they are made from metals and plastics so the body doesn't recognise them as foreign like living tissue
- can keep a patient alive while waiting for a donor
disadvantages
- surgery for an artificial heart can lead to bleeding and infections
- parts of the heart could wear out or the electric motor could fail
- blood doesn't flow through as smoothly, leading to blood clots and strokes
45
What are faulty heart valves?
- valves can be damaged/weakened by heart attacks, infections or old age
- this may cause valve tissue to stiffen so it wont open properly
- or it may become leaky, allowing blood to flow in both directions
- so blood doesn't circulate as effectively as normal
46
How can faulty heart valves be treated?
- damage can be treated by replacing the valve with a biological valve from humans or other mammals e.g. cows or pigs
- or it can be replaced by a mechanical valve
- (can still cause problems with blood clots)
47
How can artificial blood keep you alive?
- artificial blood is a blood substitute used to replace the lost volume of blood
- its safe and can keep people alive, even if they lose 2/3s of their red blood cells, until they produce new blood cells
- if they cant the patient will need a blood transfusion
48
What is health?
the state of physical and mental wellbeing
49
How can different diseases interact with each other?
50
What factors affect health?
- balanced diet, that provides your body with everything it needs and in the right amounts. a poor diet can affect health
- the stress you are under can cause health issues
- your life situation, if you can buy healthy food, buy condoms to prevent STDs, access to medicines to treat illnesses
51
What risk factors can cause disease?
smoking - causes cardiovascular disease, lung disease and lung cancer. it damages the walls of arteries and the cells of the lining in the lungs
obesity - can cause type 2 diabetes by making the body less sensitive or resistant to insulin
drinking too much alcohol - causes liver disease and can affect brain function by damaging the nerve cells, causing it to lose volume
- cancer can be causes by exposure to certain substances or radiation, things that cause cancer are called carcinogens e.g. ionising radiation
52
how can non-communicable diseases be costly?
53
How do cancers grow?
they are caused by uncontrolled cell growth and division resulting in the formation of a tumour (a mass of cells)
54
What are the two types of cancers?
benign
- the tumour stays in one place and doesn't spread to other tissues
- the tumour isn't cancerous so they aren't usually dangerous
malignant
- the tumour grows and spreads to neighbouring healthy tissues
- malignant cells can break off and spread to other parts of the body by travelling in the bloodstream, then invade healthy tissues and form secondary tumours
- they are cancerous so they can be dangerous and fatal
55
Does having risk factors mean you will get cancer?
Having risk factors doesn't mean you'll definitely get cancer it just means your'e at an increased risk, anyone can develop cancer
56
How have cancer survival rates increased?
- improved treatment
- being able to diagnose cancer earlier
- increased screening
57
What risk factors for cancer can be associated with lifestyle?
smoking - biggest cause of cancer including lung cancer, can also cause mouth, bowel, stomach and cervical cancer
obesity - second biggest cause for many different types like liver, kidney, bowel
UV exposure - people exposed to UV radiation from the sun have an increased chance of developing skin cancer, people who live in a sunny climate, spend a lot of time outside or frequently use sun beds are at higher risk
Viral infection
58
Can risk factors be caused by genetics?
- you can inherit faulty genes that make you more susceptible to cancer
- e.g. mutations in the BRCA genes have been linked to increased likelihood of developing breast cancer
59
What are the functions of the leaf tissues?
Epidermal tissue - covers the whole plant
Palisade layer - where photosynthesis happens
Spongey mesophyll - contains big air spaces to allow gases to diffuse in and out of cells
Xylem and phloem - transport water mineral ions and food around the plant
Meristem tissue - found at growing tips of shoots and roots, it can differentiate into lots of different type of plant cell, allowing it to grow
60
What are the features of the leaf tissues?
- The epidermal tissues are covered with a waxy cuticle to help reduce water loss by evaporation
- The upper epidermis is transparent so light can pass through to the palisade layer
- Palisade layer has lots of chloroplasts and there are near the top of the leaf where it can get the most light
- xylem and phloem deliver water and other nutrients to the leaf and take away the glucose from photosynthesis, they also help support the structure
- the tissues of the leaf are adapted for efficient gas exchange e.g. lower epidermis is full of holes called stomata which let CO2 diffuse into the leaf and the air spaces in the spongey mesophyll tissue increase the rate of diffusion of gases
61
What are the features of phloem tubes?
- made of living cells with pores in the end walls to allow cell sap to flow through
- they transport food substances (mainly dissolved sugar) made in the leaves to the rest of the plant for immediate use or for storage, this is called translocation
- the transport goes in both directions
62
What are the features of the xylem tubes?
- made of dead cells with no end walls between them, they are 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 evaporation and diffusion out of the leaves is called the transpiration system
63
How does transpiration happen?
- evaporation and diffusion from the plants leaves creates a shortage of water in the leaf
- so more water is drawn up through the roots and xylem vessels to replace it
- the same thing happens and more water is drawn up from the roots so there is a constant transpiration stream of water through the plant
(because there's more water inside the plant then outside the water escapes through the leaves by diffusion)
64
What 4 main things is transpiration affected by?
light intensity - the brighter the light, the greater the transpiration rate. Stomata close when its dark because photosynthesis cant happen in the dark so they don't need to let CO2 in.
temperature - the warmer it is, the faster transpiration happens because the water particles have more energy to evaporate and diffuse out .
air flow - the stronger the wind, the greater the transpiration rate. the water vapour is swept away, maintaining a low concentration of water outside the leaf so diffusion can happen quickly from a high to low concentration.
humidity - the drier the air around a leaf, the faster transpiration happens.
65
What is the apparatus called to estimate the rate of transpiration?
A potometer
66
How are guard cells adapted to open and close stomata?
- they have a kidney shape which opens and closes the stomata
- thin outer walls and thickened inner walls make opening and closing work
- there're sensitive to light and close at night to save water without losing out on photosynthesis
- when they have lots of water the guard cells fill with it and go turgid, this makes stomata open so gases can be exchanged for photosynthesis
- they become flaccid when plant is short of water making stomata close to help water vapour escaping
They are adapted for gas exchange and controlling water loss within a leaf.
67
Where are stomata found?
on the lower surface of the leaves because its shaded and cooler so less water is lost through the stomata
