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AH Biology > 2. Organisation > Flashcards

2. Organisation Flashcards

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1
Q

What are cells?

A

Cells are the basic building blocks of all living organisms

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2
Q

What is a tissue?

A

A tissue is a group of cells with a similar structure and function

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3
Q

Give examples of tissues

A

Muscular tissue
Epithelial Tissue

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4
Q

What is an organ?

A

An organ is a collection of tissues, performing specific functions

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5
Q

Give an example of an organ, and what types of tissues it contains?

A

The stomach is an example of an organ, which contains muscle tissue and epithalial tissue

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6
Q

What is an organ system?

A

An organ system is a group of organs, working together to perform bodily functions

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7
Q

Give two example of an organ system

A
  • Digestive System
  • Circulatory System
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8
Q

What do organ systems form?

A

Organ systems work together to form the organism - which is the whole living thing

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9
Q

What is the purpose of the digestive system?

A

The purpose of the digestive system is to digest and absorb food

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10
Q

What are the three main nutrients?

A

Carbohydrates, Protein & Lipids

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11
Q

Explain why food/nutrients need to be broken down?

A

Because they are large molecules that are too large to be absorbed into the bloodstream

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12
Q

What do digestive enzymes do during digestion?

A

During digestion, digestive enzymes convert large, insoluble food molecules into smaller, soluble molecules that can be absorbed into the bloodstream via the small intestine

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13
Q

What are enzymes made up of?

How do they function?

A
  • Enzymes are large protein molecules
  • They function as biological catalysts and speed up the rate of the reaction but are not used up in it
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14
Q

What are enzymes made up of?

A

Enzymes are made up of large protein molecules, which are formed from long chains of amino acids that are folded up to produce an enzyme molecule with a unique shape (active site)

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15
Q

What is the active site?

A

The active site is the unique shape within the enzyme molecule where only a specific type of substrate molecule will fit into

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16
Q

Why do enzymes only catalyse specific reactions?

A

Enzymes only catalyse specific reactions due to the unique shape of their active site

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17
Q

Describe the lock and key theory

A
  1. The active site has a shape that is complementary to one type of substrate
  2. When an enzyme and substrate with complementary shapes collide, they substrate binds into the active site of the enzyme
  3. The enzyme catalyses the breakdown of the substrate
  4. The products are released from the active site
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18
Q

What is metabolism?

A

Metabolism is the sum of all the reactions happening in a cell or in the body

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19
Q

What do enzymes do in terms of metabolism?

A

Enzymes speed up and catalyse the metabolic reactions in the body

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20
Q

What types of metabolic reactions do enzymes catalyse?

A
  • Building larger molecules from smaller molecules (eg. glucose to starch)
  • Changing one molecule to another (eg. frutcose to glucsoe)
  • Breaking down larger molecules into smaller molecules (eg. carbohydrates to glucose)
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21
Q

How are enzymes held together?

A

Enzymes are held together by chemical bonds that can be affected by temperature or pH

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22
Q

Which 2 factors have an effect on enzyme action?

A
  • Temperatures
  • pH
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23
Q

Explain why increasing temperature affects enzyme activity

A
  • As the temperature increases, there is more kinetic energy, which means the number of successful collisions between the active site and substrate increase
  • This increases enzyme activity
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24
Q

What is the optimum temperature for Enzymes

A

Around 37°C

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25
Q

What happens to enzymes at extremely high temperatures?

A
  • The chemical bonds between the long chains of amino acids break
  • This changes the shape of the active site, so that the substrate can no longer fit into the active site
  • Which results in the enzyme becoming denatured
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26
Q

What is a denatured enzyme?

A

A denatured enzyme is when the active site loses its shape so that the substrate no longer fits

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27
Q

What happens to enzymes at:
- Low temperatures
- Extremely High Temperatures

A
  • At low temperatures, they work slowly
  • At high temperatures they denature
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28
Q

Describe the optimum pH for most enzymes

A

The optimum pH for most enzymes is 7, but some that are produced in acidic conditions, such as the stomach, have a lower optimum pH

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29
Q

Why do enzymes denature at extremely low/high pHs?

A
  • If the pH is too high or too low, it will affect the forces that hold the chains of amino acid
  • This will change the shape of the active site, so that the substrate will no longer fit in the active site of the enzyme, and the enzyme becomes denatured
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30
Q

How do we calculate the rate of enzyme reaction?

A

By calculating the gradient of the graph

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31
Q

Name the 3 types of digestive enzymes and descibe their functions

A
  • Carbohydrase breaks carbohydrates into Simple Sugars (like glucose)
  • Protease breaks proteins into Amino Acids
  • Lipase breaks Lipids into Glycerol and Fatty Acids
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32
Q

What does a lipid molecule consist of?

A

A lipid molecule consists of a molecule of glycerol attached to three molecules of fatty acids

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33
Q

What is amylase?

A

Amylase is a type of carbohydrase that breaks starch into glucose

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34
Q

Where are the main digestive enzymes produced and broken down?

The site of action is where enzymes break down substances

A
  • Carbohydrates and Amylase are produced in the salivary glands and pancreas, and break down substances in the mouth and small intestine
  • Protease is produced in the stomach, pancreas and small intestine and its site of action is the stomach and small intestine
  • Lipase is produced in the pancreas and small intestine and its site of action is the small intestine

The site of action is where enzymes break down substances

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35
Q

What is the purpose of hydrochloric acid?

A

Hydrochloric acid breaks the food down quickly and helps the enzymes to digest the food quickly

Also kills any pathogens

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36
Q

What is bile?

A

Bile is an alkaline substance that is produced in the liver and stored in the gallbladder

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37
Q

What are the two functions of bile?

A
  • Bile is alkaline to neutralise the hydrochloric acid in the digested food, to prevent enzymes from becoming denatured
  • Bile is also alkaline because the enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach, so by creating alkaline conditions, bile speeds up the rate of enzyme activity
    2. Bile emulsifies fat/lipid by breaking it down to form small droplets, which increases the surface area
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38
Q

Explain why bile is alkaline

A
  • Bile is alkaline to neutralise the hydrochloric acid in the digested food, to prevent enzymes from becoming denatured
  • Bile is also alkaline because the enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach, so by creating alkaline conditions, bile speeds up the rate of enzyme activity
39
Q

Explain why bile emulsifies fat

A
  • Bile emulsifies fat by breaking the fat / lipid into smaller droplets
  • To increase the surface area, which increases the rate of fat breakdown and digestion
40
Q

What are the products of digestion used for?

A
  • The products of digestion are used to build new carbohydrates, lipids and proteins
  • Some glucose is used in respiration
41
Q

What is the heart?

A

The heart is an organ that pumps blood around the body

42
Q

What is special about the heart?

A

The heart is a double circulatory system

43
Q

What are the 4 chambers inside the heart?

A
  • Right Atrium
  • Right Ventricle
  • Left Atrium
  • Left Ventricle
44
Q

Why is the heart a double-circulatory system?

A

The heart is a double circulatory system because blood passes through the heart twice on each pump, and it flows to two different locations
- The right ventricle pumps deoxgenated blood from the heart to the lungs, and then the blood returns back to the heart as oxygenated blood
- Whilst the left ventricle pumps oxygenated blood around the rest of the body

45
Q

What is the advantage of a double cicrulatory system?

A
  • It is very efficient
  • Because the blood has to pass through the body twice
  • The pressure of the oxygenated blood can be raised before sending it to the rest of the body, which increases the speed of blood flow
  • So more areas of the body recieve oxygenated blood quickly
46
Q

Label the diagram

A
47
Q

Describe the process of which blood flows

A
  1. Deoxygenated blood enters through the vena cava
  2. It flows through the right atrium
  3. The blood flows down into the right ventricle
  4. The right ventricle pumps the blood out of the pulmonary artery to the lungs, where gas exchange takes place
  5. The blood becomes oxygenated and returns to the heart via the pulmonary vein
  6. It flows into the left atrium and then to the left ventricle
  7. The left ventricle pumps the blood out of the aorta and to the rest of the body
48
Q

What are the adaptations of the heart?

A
  • The walls of the ventricles are thicker than the walls of the atria as they pump blood out of the heart, so they need to generate a high pressure
  • The wall of the left ventricle is thicker than the the wall of the right ventricle as it needs to pump blood around the whole body, so it needs a higher pressure. Whereas the right ventricle only needs to pump blood to the lungs which is closer to the heart
  • Valves between the atria and ventricles prevent the backflow of blood back into the atria when the ventricles contract
49
Q

What is the function of coronary arteries?

A

Coronary arteries run outside of the heart to supply the cells of the heart tissue with oxygen

50
Q

Name 5 blood vessels associated with the heart

A
  • aorta
  • vena cava
  • pulmonary artery
  • pulmonary vein
  • coronary arteries
51
Q

How is the heart rate controlled?

A

The heart rate is controlled by a group of cells in the right atrium that act as a pacemaker

52
Q

Why are artificial pacemakers used?

A

Artificial pacemakers, which are electrical devices, can be used to correct irregularities in the heart

53
Q

How are artificial pacemakers used to correct irregularities in the heart?

A

They produce regular and strong electrical signals that stimulate the heart to contract and beat

54
Q

What is the approximate value of the natural resting heart rate?

A

70 beats per minute

55
Q

What are the 3 types of blood vessels and their function?

A
  • Arteries - Carry blood away from the heart and to the organs at high pressure
  • Capillaries - Allow the exchange of molecules between blood and body cells
  • Veins - Return blood back to the heart and away from the organs at low pressure
56
Q

How are arteries adapted for their function?

A
  • Arteries have a thick wall containing muscle to prevent bursting
  • They have elastic fibres that allow the arteries to expand when blood surges at high pressure (at every heartbeat) and then recoil afterwards, which helps to maintain the pressure
  • They have a narrow lumen to maintain pressure
57
Q

What type of blood do arteries carry?

A

Arteries carry oxygenated blood, except for the pulmonary artery

58
Q

What are capillaries?

A
  • Arteries branch into much smaller blood vessels, called capillaries
  • They are a huge network of tiny vessels linking the arteries and veins
59
Q

How are capillaries adapted for their function?

A

Capillaries have a very thin, one cell thick wall to create a short diffusion pathway, maximising the exchange by diffusion

60
Q

What substances diffuse through the capillaries?

A
  • Oxygen and glucose move out of the blood and into the cells
  • Carbon Dioxide moves out of the blood and into the body cells
61
Q

How are veins adapted for their function?

A
  • Veins have a wider lumen, to allow more low pressure blood to flow through, so there is less resistance to blood flow
  • They have relatively thin walls than arteries as it only carries blood at low pressure, so there is no need for thick walls
  • They have valves to prevent the backflow of blood
62
Q

Explain how valves in the veins work?

A

The valves open as the blood flows through them in the correct direction
When the blood starts to flow backwards, the valves shut

63
Q

What type of blood do veins carry?

A

Veins carry deoxygenated blood, except for the pulmonary vein)

64
Q

Explain how gas exchange in the lungs work?

A

Air is breathed into the lungs throuhg the trachea
The trachea divides into two smaller tubes called bronchi (with one passing to each lung)
The bronchi then divide into even smaller tubes called bronchioles
The bronchioles then divide until they end up in tiny air sacs called alveoli

65
Q

Explain the structure and function of alveoli

A

Function: The alveoli are where gases are exchanged and diffused
Oxygen is diffused from the air in the lungs into the bloodstream and carbon dioxide is diffused out of the bloodstream

Structure: The alveoli are surrounded by a network of capillaries

66
Q

How are alveoli adapted to increase the gas exchange by diffusion?

A
  • Millions of tiny alveoli provide a huge surface area
  • They have very thin walls, providing a shorter diffusion pathway
  • The capillaries have a rich blood supply, maintaining the concentration gradient - as once the oxygen diffuses into the blood, the blood rapidly flows away
67
Q

What is ventilation/breathing?

A

Ventilation/breathing is when oxygen is brought into the blood and carbon dioxide is taken away

68
Q

How does ventilation/breathing work?

A

Ventilation is when:
- The ribcage moves up and out, increasing the volume of the chest
- An increased volume results in lower pressure
- Air is frawn into the chest as air moves from areas of high pressure (the environment) to areas of low pressure (the lungs)
- Vice versa when exhaling

69
Q

How is a steep concentration gradient maintained during the diffusion of oxygen in the lungs?

A
  • Ventilation moves oxygen-rich air into the lungs and takes carbon dioxide out
  • Meanwhile, the rich blood supply ensures that oxygenated blood is removed rapidly
  • This maintains a significant difference in the concentrations as there is lots of oxygen in the lungs and no oxygen in the bloodstream (opposite for co2)
  • This results in a steep concentration gradient and a rapid rate of diffusion
70
Q

What type of cell organisation does blood go under?

A

Blood is a tissue

71
Q

What are the four components of blood

A
  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
72
Q

Plasma

& function

A
  • Plasma is the liquid part of the blood consisting of mostly water
  • Plasma carries red blood cells, white blood cells and platelets, which are suspended in the plasma

Plasma also transports:
- Small, soluble products of digestion (such as amino acids or glucose), from the small intestine to the individual cells around the body
- Carbon Dioxide produced by the body cells during respiration to the lungs, for it to be breathed out
- Urea formed in the liver (due to the breakdown of excess proteins) where it is transported to the kidneys, and then excreted as urine

73
Q

Red blood cells

Function & Adaptations

A

Red blood cells carry oxygen from the lungs to the body cells

Their adaptations:
- They are packed with the oxygen-carrying red pigment, haemoglobin, which binds to oxygen in the lungs and then carries it to the organs, where the haemoglobin is released to the body cells for respiration
- Red blood cells have no nucleus, which means that they have more space for haemoglobin, allowing more room to carry oxygen
- Biconcave disc shape which gives them an increased surface area to volume ratio for diffusion of oxygen

74
Q

White blood cells

Function & Adaptations

A
  • White blood cells form part of the immune system as they are responsible for recognising and defending against pathogens
  • They defend the body in different ways. Some (phagocytes) engulf pathogens and then release enzymes to digest them. Some (lymphocytes) produce antibodies against microorganisms Some produce anti-toxins that neutralise toxins produced by the pathogens
  • White blood cells have a nucleus that contains DNA, which encodes the instructions that the white blood cells need to do their job
75
Q

Platelets

A

Platelets are tiny fragments of cells and their job is to aid blood clot

76
Q

Describe how platelets help the blood to clot?

A
  • Platelets releases clotting substances and clump together to help form the blood clot at the site of the wound
  • The clot dries and hardens to form a scab, which allows new skin to grow underneath while preventing microorganisms from entering
  • This also prevents excessive blood to flow and bleed, such as from damaged blood vessels
77
Q

What happens in coronary heart diease?

A
  • In coronary heart disease, layers of fatty material build up inside the
  • coronary arteries
  • This causes the coronary arteries to narrow
  • This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle
  • This could lead to a heart attack
78
Q

Describe 2 ways coronary heart disease can be prevented?

A

Coronary heart disease can be prevented using stents and statins

79
Q

Describe what stents are

A

Stents are metal mesh tubes that are inserted inside the coronary arteries to support it and keep it open

80
Q

Describe what statins are

A

Statins are drugs which are used to reduce blood cholesterol levels, which slows down the rate of fatty material deposit

81
Q

What is the disadvantage of using statins?

A
  • Statins can have unwanted side effects such as liver and digestion problems
  • The drug also needs to be taken continuously which may be an inconvienience
82
Q

What is the advantage of using statins?

A
  • It is effective as it reduces the risks of coronary heart disease, strokes and heart attacks by reducing the levels of bad cholsesterol
  • It increases the level of good cholesterol
83
Q

What is the advantage of using stents?

A

Stents allow blood to flow normally through the artery, which makes it effective in lowering the risk of a heart attack

84
Q

What is the disadvantage of using stents?

A
  • Stents do not treat the underlying cuases of the disease, so it will not prevent other regions of the coronary arteries from narrowing
  • There is a risk of blood clots forming near the stents
85
Q

What is another type of cardivascular heart disease?

Except for Coronary Heart Disease

A

Faulty Heart Valves

86
Q

Explain how heart valves can become faulty?

A

Heart valves can become faulty after withstanding a lot of pressure, especially after old age

87
Q

Symptoms & consequences of faulty heart valves

A
  • Heart valves become stiff and do not fully open, so less blood passes through when the heart is pumped.
  • Heart valve might develop a leak, where the blood flows in the wrong direction.
  • This causes the heart to become less efficient as the oxygen transport is reduced
  • This results in people becoming breathless and maybe death or results in fatigue and tiredness
88
Q

How can faulty heart valves be replaced?

A

Faulty heart valves can be replaced by using:
- Mechanical valves, which are artificial and made of metals or polymers
- Biological Valves, which are taken from animals such as pigs or cattle - or even human donors

89
Q

What is the advantage and disadvantage of using a mechanical valve?

A

Advantage: Mechanical valves last a very long time
Disadvantage: Medication is needed for the rest of your life to prevent blood from clotting around the valve

90
Q

What is the advantage and disadvantage of using a biological valve?

A

Advantage: Biological valves work extrememly well and does not require any medication
Disadvantage: It only lasts for 12-15 years

91
Q

What happens during heart failure?

A

In the case of heart failure a donor heart, or heart and lungs can be transplanted

92
Q

Why are artificial hearts occassionally used instead of heart transplants to treat people with heart failure?

A

There are not enough donated hearts around

93
Q

What is the purpose of artificial hearts during heart failure?

A
  • Artificial hearts are temporarily used to keep a patient while they wait for a heart transplant
  • They are also used to allow the heart to rest as an aid to recovery

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