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Topic 2 - Organisation Flashcards

(86 cards)

1
Q

What is an tissue?

A

A group of similar cells working together to carry out a specific function.

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2
Q

What is an organ and give an example?

A

A group of different tissues that work together to perform a particular function.
The stomach.

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3
Q

What is an organ system and give an example.

A

A group of organs that work together to perform a particular function.
The digestive system.

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4
Q

What is an enzyme?

A

An enzyme is a biological catalyst.
They are basically large proteins made of large chains of amino acids.

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5
Q

What is an active site of an enzyme?

A

It is complementary to the substrate.

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6
Q

What happens if the substrate does not fit in the active site?

A

The reaction will not be catalysed.

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7
Q

Explain the lock and key model.

A

Scientists originally thought substrates fit perfectly into the active site like a key.

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8
Q

Explain the induced to fit model.

A

Scientists now know the enzyme changes shape slightly as it binds to the substrate.
The active site is complementary to the substrate.

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9
Q

What is the optimum temperature for enzymes to work?

A

37 degrees around body temperature.

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10
Q

How does temperature increase affect the functioning of enzymes?

A

At the start the temperature increases and so does the rate of reaction as all of the particles have more kinetic energy increasing collisions. However after about 37 degrees the rate of reaction decreases rapidly as the high temperature breaks the bonds holding the enzymes together. Then the active site starts to change shape. If it changes shape enough the enzyme will not be able to bind to the substrate this is called ‘denatured’.

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11
Q

What is the optimum pH for enzymes?

A

Mostly pH 7 but depends where they work such if they work in the stomach it would be like 2.

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12
Q

Write a method to describe the effect of pH on the rate of reaction of amylase and give the variables and how do you calculate the rate.

A

Independent variable - pH of the buffer solution.
Dependent variable - Rate of starch breakdown.
Control variables - Temperature of the reaction, concentration of amylase, concentration of starch, volume of solutions.

Set the water bath to 35 degrees and wait for the water to warm and place a test tube inside.
Then use a syringe to add 1 cm cubed of amylase solution and 1cm cubed of buffer solution into the test tube and wait 5 minutes.
Next use a different syringe to add 5cm cubes of starch solution to the boiling tube and immediately mix and start a stop watch.
Every 30 seconds take a little bit of your solution out with a pipette and drop it into the spotting tile with iodine. Repeat this until the iodine changes colour from blue - black to brown/orange and stop the stopwatch.
Repeat experiment with different buffer solutions with different pH.

Rate = 1000/time

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13
Q

Why do we need digestion for carbohydrates, proteins, and lipids?

A

As they are big molecules so have to be broken down into smaller pieces this is where enzymes are involved to be absorbed into our bloodstream.

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14
Q

How is starch absorbed into our blood stream?

A

Amylase breaks down starch into maltose.
Maltase breaks down maltose to glucose which is small enough to absorb.

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15
Q

How are proteins absorbed into our bloodstream?

A

Proteins are broken down by protease enzymes into amino acids.

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16
Q

How are lipids absorbed into our blood stream?

A

They are broken down by lipase enzymes into glycerol + fatty acids

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17
Q

Define digestion.

A

The process by which we break down large food molecules into smaller molecules. Such as starch into glucose.

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18
Q

Define absorption.

A

The process of which we absorb small molecules into the bloodstream.

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19
Q

What is the role of the teeth?

A

To physically break down the food by chewing which increases the surface area of the food therefore it is easier for enzymes to break it down.

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20
Q

What is the role of the salivary gland?

A

Releases saliva which contains the enzyme amylase which digests starch into maltose.

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21
Q

Where does the food go through after you swallow it?

A

The Oesophagus.

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22
Q

What is the role of the stomach?

A

Contracts muscular walls to churn food.
Produces pepsin which is a protease enzyme.
Produces hydrochloric acid - kills bacteria and provides correct pH of pepsin enzyme.

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23
Q

What enzymes are produced in the pancreas and what happens to them?

A

All of them
Amylase
Protease
Lipase
They are then released into the small intestine.

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24
Q

Where is bile produced and where is it stored and what is the role of it?

A

Bile is produced in the liver and stored in the Gallbladder.
The role of bile is neutralise stomach acid (bile is alkaline)
It also emulsifies lipids. (breaks large bits of fat and oil into tiny droplets) This gives the lipids a larger surface area for digestive enzymes to work on.

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25
What is the role of the small intestine?
Where most of the digestion takes place. It produces protease, lipase and amylase to complete digestion.
26
What is the role of villi?
Increases surface area to maximise absorption of nutrients into the bloodstream. Villi has a huge surface area for diffusion to take place. They are one cell thick so there is a short distance for diffusion. They also have a good blood supply to maintain the concentration gradient. Cells of villi also have microvilli to further increase the surface area.
27
What is the role of the large intestine?
Absorbs most of the excess water leaving a dry mixture (faeces). Faeces is stored in the rectum and is removed through the anus.
28
What are the 4 food tests?
Benedict's test - Reducing Sugars Iodine test - Starch Biuret test - Proteins Emulsion test - Lipids
29
How do prepare your food sample in the food tests?
You first break your food up using a mortar and pestle. Then you add it in a beaker and fill with distilled water and stir with a glass rod until some of it dissolves. Then you filter your solution with a funnel and filter paper to remove solid bits. The solution you now have is the sample.
30
What colour is Benedict's solution and what colour does it turn if sugar is present?
Benedict's solution is blue so if no sugars are present it will stay blue. If sugar is present it will turn green, yellow or brick red. Depending on the concentration.
31
What colour will the iodine solution turn if starch is present?
If none are present will stay browny orange. If starch is present, it will turn blue black.
32
What colour will the biuret solution turn if proteins are present?
If none are present it will stay blue. If they are present it will turn from blue to purple.
33
What colour does the ethanol turn when lipids are present?
Cloudy white.
34
List the pathway of air.
Mouth/nose Trachea Bronchi Bronchioles Alveoli
35
What is the structure of alveoli?
They are one cell thick to make the diffusion distance shorter increasing the rate at which carbon dioxide and oxygen can diffuse across. Alveoli have large surface area. Alveoli walls are moist to allow gasses to dissolve. Increasing the rate of diffusion.
36
What is the role of the blood?
Fluid which carries all the substances such as oxygen, nutrients, cells and waste products.
37
What is the role of blood vessels?
Holds the blood and directs it around the body.
38
What is the role of the heart?
Pumps blood to ensure it keeps flowing through the vessels.
39
Name the 4 chambers of the heart.
40
What are the roles of valves?
Ensures blood only flow in one direction.
41
Which side of the heart is the left and which is the right?
They are flipped the left side is on the right side on paper and the right side is on the left side on paper.
42
Why does the left ventricle have thicker muscular walls than the right ventricle?
The left ventricle has thicker muscular walls because it needs to pump blood at high pressure around the whole body, whereas the right ventricle only pumps blood to the lungs
43
Describe the flow of deoxygenated blood starting at the vena cava changing in to oxygenated blood ending in the aorta.
Vena Cava is where deoxygenated blood enters the heart from around the body. Then it goes to the right atrium where it contracts. Then it goes to the right ventricle where it also contracts. Then it goes to the pulmonary artery which carries the blood to the lungs where it becomes oxygenated. The now oxygenated blood leaves the pulmonary vein and carries it into the left atrium. The left atrium contracts and the blood goes to the left ventricle which also contracts. Then the blood is pumped into the aorta which travels around the body to our tissues.
44
Where does the heart get its own supply of oxygenated blood?
Coronary arteries
45
What do arteries do?
Carry high pressure oxygenated blood away from the heart.
46
What do veins do?
Carry lower pressure deoxygenated blood back to the heart.
47
What is the structure of the artery
Since arteries are under high pressure, they have strong and elastic walls. The walls are thick. It has narrow lumen. Thick layer of muscle to make them strong.
48
What is the role and structure of the capillaries.
Arteries branch into capillaries which are tiny. They carry the blood really close to every cell in the body to exchange substances with them. They have a thin wall - only one cell thick decreasing diffusion distances. They have very small lumen.
49
What is the structure of the veins?
Since it has low blood pressure, it has a widest lumen, Thin walls, Small layer of elastic fibre and muscle. Contains valve to ensure blood flows in the right direction.
50
What is the equation to calculate the rate of blood flow?
How much blood flowed / time taken
51
What are the four main things the blood contains?
Red blood cells White blood cells Platelets Plasma
52
What is the role of red blood cells and what is there structure?
Carry oxygen from the lungs to our tissues so the cells can use them in cellular respiration. Has a biconcave disc this gives a large surface area for absorbing oxygen. They don't have a nucleus.
53
What is haemoglobin
Haemoglobin is a red pigment in red blood cells that binds to oxygen in the lungs to become oxyhaemoglobin and transports it to the body's cells for respiration.
54
What do white blood cells do?
Defend us against infection by; Phagocytosis - Engulfing pathogens, Produce antibodies - That bind onto pathogens and help destroy them. Produce anti toxins that neutralise any toxins They have a nucleus.
55
What do platelets do and what is the structure?
They help blood clot at a wound to stop loss of blood and microorganisms getting in.
56
What does plasma do?
Carries just about everything; Red blood cells White blood cells platelets. Carries nutrients such as Glucose and amino acids. Waste products such as CO2 and urea Hormones Proteins Antibodies and antitoxins.
57
What is a pacemaker and what does it do?
A pacemaker is a group of cells in the right atrium that controls the resting heart rate by sending electrical impulses to the heart muscle. Artificial pacemakers are devices used to correct irregular heartbeats.
58
What is coronary heart disease?
Where the coronary arteries start to get blocked by the buildup of fatty materials. This causes the lumen of the artery to get narrower meaning less blood can flow through and less oxygen reaches the heart muscle. This can potentially cause a heart attack.
59
What are the two ways to treat coronary heart disease?
Stents Statins
60
What are stents and what are the pros and cons?
Stents are expandable tubes that widen the arteries so the blood can flowing. Benefits Quick surgery Lasts a long time Drawbacks Requires surgery that has risks such as heart attacks and infection. Can lead to blood clot near the stent.
61
What are statins and what are the pros and cons?
Statins are drugs that reduce the amount of LDL cholesterol present in the bloodstream and. This slows the rate of fatty deposits. Benefits Lowers risk of; Coronary heart disease Strokes Heart attacks. It also can increase the amount of good cholesterol HDL in your bloodstream. Some studies suggest they alsos help prevent other diseases. Drawbacks Statins are long term and have to be taken regularly Statins can have negative side effects such as headaches or serious side effects such as kidney failure. The effect of statins is not instant takes time.
62
What is LDL cholesterol and what is HDL cholesterol?
LDL = "Bad" cholesterol. HDL = "Good" cholesterol.
63
How do valves in the heart get damaged or weakened?
Old age Heart attack Infection
64
What are the two main problems people get with valves in the heart?
The valve has become stiff so won't open fully meaning not enough blood can pass through. The valve will not close properly so blood can leak backwards.
65
What are the two ways to replace faulty valves?
Replace with a biological one either from a human or other mammals such as pigs or cows. Or they can be replaced with mechanical valves man made. Both require surgery.
66
What is heart failure?
Where the heart cannot pump blood.
67
How do you treat heart failure?
Biological heart transplant from a donor this can take ages and could be rejected by our body immune system. Or artificial heart - mechanical device that pumps blood but usually a temporary fix until a donor heart can be found.
68
What is obesity a risk factor for?
Diabetes and heart attacks.
69
What is air pollution and smoking a risk factor for?
Lung cancer. Cardiovascular disease. Lung disease. Toxins in smoke can damage cells in lungs.
70
What are studies proving lifestyle in developed countries and less developed countries?
In developed countries non-communicable disease are more common due to higher income and can buy fat food. More deprived areas are more likely to smoke, have a poor diet and not exercise.
71
Define cancer.
Cancer is a disease where abnormal cells grow uncontrollably and spread to other parts of the body.
72
What are the two types of cancer and define them.
Benign - This is where the tumour grows until there is no more room. Stays in once place rather than invading other tissues in the body. Malignant - This is where the tumour grows and spreads to neighbouring healthy tissues. Cells can break off and spread to other parts of the body via the bloodstream.
73
What are things that make you more likely to develop cancer?
Smoking - lung cancer Obesity UV exposure - Skin cancer Viral infection Inherited faulty genes
74
What is the function of a leaf?
It is the site of photosynthesis.
75
How does photosynthesis occur in the leaf from the air?
The carbon dioxide diffuses into the leaf from the outside air from lots of little holes called the stomata. Each leaf has thousands of stomata scattered over the lower epidermis. Once the carbon dioxide diffuses through the stomata it moves up the leaf into the spongy mesophyll which has lots of air gaps so the gas can easily diffuse into the next layer the palisade mesophyll where most photosynthesis occurs so is full of chloroplasts. Above this is the upper epidermis which is almost transparent so sunlight can get into the palisade cells the the chloroplasts beneath.
76
Where do the sugar molecules go after photosynthesis is complete?
They are carried to rest of the plant by the phloem.
77
What does the xylem do?
Bring water from the roots to the palisade cells to use during photosynthesis.
78
How does the leaf reduce water loss?
The leaf contains a waxy cuticle - thin waterproof layer of lipids. Stomata stays open for as short time as possible to maximise Carbon dioxide absorption and minimise water loss this is done through the guard cells.
79
What do the guard cells do?
Each stoma (singular stomata) is formed from the gap of two guard cells. When the plants has lots of water the plant cells are turgid making the gap between them larger allowing more carbon dioxide to diffuse through. When the plant does not have much water the guard cells will lose water due to osmosis so it becomes flacid this means it no longer takes carbon dioxide but it conserves water. Guard cells also are sensitive to light so it closes at night.
80
Where is the meristem formed and what does it do?
Found in the growing roots and shoots. It can differentiate into different cells (plant stem cell)
81
What is the difference between translocation and transpiration?
Translocation is the transport of sugars through the phloem. Transpiration is the transport of water through the xylem.
82
What is the phloem made of?
Made of columns of elongated living cells with small pores in the end wall to allow cell sap to flow through.
83
What are xylem made of?
Made of dead cells joined end to end with no end walls between the and a hole down the middle. They carry water and mineral ions from roots to the stem and leaves.
84
Define transipration.
The evaporation and diffusion of water from a plant's surface most transpiration occurs at the leaves most transpiration occurs at the leaves.
85
What are 4 things that affect the rate of transpiration.
Light intensity - The brighter the light the greater the transpiration rate. Temperature - The warmer it is the faster transpiration occurs. Air flow - The better the air flow around a leaf the greater the transpiration rate. Humidity - The drier the air the faster transpiration occurs.
86