1.2 Organisation Flashcards
(101 cards)
1
Q
What are cells?
A
Cells are the basic building blocks of all living organisms
2
Q
What is a tissue?
A
A tissue is a group of cells with a similar structure and function
3
Q
Give examples of tissues
A
Muscular tissue
Epithelial Tissue
4
Q
What is an organ?
A
An organ is a collection of tissues, performing specific functions
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
6
Q
What is an organ system?
A
An organ system is a group of organs, working together to perform bodily functions
7
Q
Give two example of an organ system
A
- Digestive System
- Circulatory System
8
Q
What do organ systems form?
A
Organ systems work together to form the organism - which is the whole living thing
9
Q
What is the purpose of the digestive system?
A
The purpose of the digestive system is to digest and absorb food
10
Q
What are the three main nutrients?
A
Carbohydrates, Protein & Lipids
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
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
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
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)
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
16
Q
Why do enzymes only catalyse specific reactions?
A
Enzymes only catalyse specific reactions due to the unique shape of their active site
17
Q
Describe the lock and key theory
A
- The active site has a shape that is complementary to one type of substrate
- When an enzyme and substrate with complementary shapes collide, they substrate binds into the active site of the enzyme
- The enzyme catalyses the breakdown of the substrate
- The products are released from the active site
18
Q
What is metabolism?
A
Metabolism is the sum of all the reactions happening in a cell or in the body
19
Q
What do enzymes do in terms of metabolism?
A
Enzymes speed up the metabolic reactions in the body
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. fructose to glucose)
- Breaking down larger molecules into smaller molecules (eg. carbohydrates to glucose)
21
Q
How are enzymes held together?
A
Enzymes are held together by chemical bonds that can be affected by temperature or pH
22
Q
Which 2 factors have an effect on enzyme action?
A
- Temperatures
- pH
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
24
Q
What is the optimum temperature for Enzymes
A
Around 37°C
25
What happens to enzymes at extremely high temperatures?
* The change 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
26
What is a denatured enzyme?
A denatured enzyme is when the active site loses its shape so that the substrate no longer fits
27
What happens to enzymes at:
- Low temperatures
- Extremely High Temperatures
* At low temperatures, they work slowly
* At high temperatures they denature
28
Describe the optimum pH for most enzymes
The optimum pH for most enzymes is 7.
29
Why do enzymes denature at extremely low/high pHs?
* 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
30
How do we calculate the rate of enzyme reaction?
By calculating the gradient of the graph
31
Name the 3 types of digestive enzymes and descibe their functions
* **Carbohydrase** breaks carbohydrates into Simple Sugars (like glucose)
* **Protease** breaks proteins into Amino Acids
* **Lipase** breaks Lipids into Glycerol and Fatty Acids
32
What does a lipid molecule consist of?
A lipid molecule consists of a molecule of glycerol attached to three molecules of fatty acids
33
What is amylase?
Amylase is a **type** of carbohydrase that breaks starch into glucose
34
Where are the main digestive enzymes produced and broken down?
## Footnote
The site of action is where enzymes break down substances
* **Lipase** is produced in the pancreas and small intestine and its site of action is the small intestine
* **Protease** is produced in the stomach, pancreas and small intestine and its site of action is the stomach and small intestine
* **Carbohydrates** and **Amylase** are produced in the salivary glands and pancreas, and break down substances in the mouth and small intestine
35
What is the purpose of hydrochloric acid?
Hydrochloric acid breaks the food down quickly and helps the enzymes to digest the food quickly
Also kills any pathogens
36
What is bile?
Bile is a sour alkaline substance that is produced in the **liver** and stored in the gallbladder
37
What are the two functions of bile?
* Bile is alkaline to neutralise the hydrochloric acid in the digested food, to prevent enzymes from becoming denatured
*Speeds up enzyme activity in the small intestine
2. Bile emulsifies fat/lipid by breaking it down to form small droplets, which increases the surface area
38
Explain why bile is alkaline
* 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 optimum pH than those in the stomach, so by creating alkaline conditions, bile speeds up the rate of enzyme activity
39
Explain why bile emulsifies fat
* 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
What are the products of digestion used for?
* The products of digestion are used to **build new carbohydrates, lipids and proteins**
* Some glucose is used in respiration
41
What is the heart?
The heart is an organ that pumps blood around the body
42
What is special about the heart?
The heart is a double circulatory system
43
What are the 4 chambers inside the heart?
* Right Atrium
* Right Ventricle
* Left Atrium
* Left Ventricle
44
Why is the heart a double-circulatory system?
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
What is the advantage of a double cicrulatory system?
* It is very efficient as 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 receive oxygenated blood quickly
46
Label the diagram
47
Describe the process of which blood flows
1. **Deoxygenated** blood enters through the **vena cava**
1. It flows through the **right atrium**
1. The blood flows down into the **right ventricle**
1. The right ventricle pumps the blood out of the **pulmonary artery** to the **lungs**, where **gas exchange** takes place
1. The blood becomes **oxygenated** and returns to the heart via the **pulmonary vein**
1. It flows into the **left atrium** and then to the **left ventricle**
1. The left ventricle pumps the blood out of the **aorta** and to the rest of the body
48
What are the adaptations of the heart?
* 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** when the ventricles contract
49
What is the function of coronary arteries?
**Coronary arteries** run outside of the heart to supply oxygen to the cells of the heart tissue.
50
Name 5 blood vessels associated with the heart
* aorta
* vena cava
* pulmonary artery
* pulmonary vein
* coronary arteries
51
How is the heart rate controlled?
The heart rate is controlled by a **group of cells** in the **right atrium** that act as a **pacemaker**
52
Why are artificial pacemakers used?
**Artificial pacemakers**, which are electrical devices, can be used to correct irregularities heartbeats in the heart
53
How are artificial pacemakers used to correct irregularities in the heart?
They produce regular and strong electrical signals that stimulate the heart to contract and beat
54
What is the approximate value of the natural resting heart rate?
70 beats per minute
55
What are the 3 types of blood vessels and their function?
* **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
How are arteries adapted for their function?
* Arteries have a **thick wall** of muscle to **prevent bursting**
* They have **elastic fibers** 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
What type of blood do arteries carry?
Arteries carry oxygenated blood, except for the pulmonary artery
58
What are capillaries?
* Arteries branch into much smaller blood vessels, called capillaries
* They are a huge network of tiny vessels linking the arteries and veins
59
How are capillaries adapted for their function?
Capillaries have a very thin, **one cell thick wall** to create a short diffusion pathway, maximising the exchange by diffusion
60
What substances diffuse through the capillaries?
* 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
How are veins adapted for their function?
* Veins have a large 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
Explain how valves in the veins work?
The valves open as the blood flows through them in the correct direction
When the blood starts to flow backwards, the valves shut
63
What type of blood do veins carry?
Veins carry deoxygenated blood, except for the pulmonary vein)
64
Explain how gas exchange in the lungs work?
Air is breathed into the lungs through 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
Explain the structure and function of alveoli
**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.
Their air-sac shape increases its surface area which allows gas exchange to be quicker.
66
How are alveoli adapted to increase the gas exchange by diffusion?
* **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
What is ventilation/breathing?
Ventilation/breathing is when oxygen is brought into the blood and carbon dioxide is taken away
68
How does ventilation/breathing work?
Ventilation is when:
- The ribcage moves up and out, increasing the volume of the chest
- An increased volume results in lower pressure
- Air is drawn 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
How is a steep concentration gradient maintained during the diffusion of oxygen in the lungs?
* Ventilation moves oxygen-rich air into the lungs and takes carbon dioxide out
* Meanwhile, the rich blood supply ensures that oxygenated blood is moved 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
What type of cell organisation does **blood** go under?
Blood is a **tissue**
71
What are the four components of blood
* Plasma
* Red blood cells
* White blood cells
* Platelets
72
Plasma
| & function
* 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
Red blood cells
| Function & Adaptations
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
- **Disc-shape** which gives them an increased surface area to volume ratio for diffusion of oxygen
74
White blood cells
| Function & Adaptations
* 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
Platelets
Platelets are tiny fragments of cells and their job is to form a blood clot
76
Describe how platelets help the blood to clot?
* 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
What happens in coronary heart disease?
* In coronary heart disease, layers of fatty material build up inside the coronary arteries
* This causes the lumen 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
Describe 2 ways coronary heart disease can be prevented?
Coronary heart disease can be prevented using **stents** and **statins**
79
Describe what stents are
**Stents** are metal mesh tubes that are inserted inside the coronary arteries to support it and keep it open
80
Describe what statins are
**Statins** are drugs which are used to reduce blood cholesterol levels, which slows down the rate of fatty material deposit
81
What is the disadvantage of using statins?
* 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
What is the advantage of using statins?
* 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
What is the advantage of using stents?
Stents allow blood to **flow** normally through the artery, which makes it effective in **lowering the risk of a heart attack**
84
What is the disadvantage of using stents?
* Stents do not treat the causes 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
What is another type of cardivascular heart disease?
## Footnote
Except for Coronary Heart Disease
Faulty Heart Valves
86
Explain how heart valves can become faulty?
Heart valves can become faulty after withstanding a lot of pressure, especially after old age
87
Symptoms & consequences of faulty heart valves
* **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
How can faulty heart valves be replaced?
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
What is the advantage and disadvantage of using a mechanical valve?
**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
What is the advantage and disadvantage of using a biological valve?
**Advantage:** Biological valves work extremely well and does not require any medication
**Disadvantage:** Can be rejected by the body so can be fatal.
91
How can heart failure be treated?
In the case of heart failure a donor heart can be transplanted.
92
Why are artificial hearts occassionally used instead of heart transplants to treat people with heart failure?
There are not enough donated hearts around
93
What is the purpose of artificial hearts during heart failure?
* 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
94
How is cancer caused?
Uncontrolled division of cells.
95
What are cancer cells?
Altered or abnormal cells
96
What are the 2 types of tumors?
Malignant and Benign tumors.
97
What do malignant tumor cells do?
They invade neighboring tissues (metastasis), move into the blood stream which can take them to any part of the body. They enter tissues and begin to divide to form secondary tumors.
98
What do benign tumors do?
They are abnormal cells and do not invade. They can be removed. They are less of a risk than malignant tumors.
99
What are Benign tumors usually surrounded by?
Cell membrane
100
What happens in the xylem?
Water and minerals are moved up the plant (transpiration).
101
What happens in the phloem?
Food molecules move up (translocation).
