B2 - Cell Organisation Flashcards
(98 cards)
1
Q
What is a tissue?
A
A group of similar cells that work together to carry out a particular function.
2
Q
What is an organ?
A
A group of different tissues that work together to perform a certain function
3
Q
What is an organ system?
A
A group of organs working together to perform a particular function
4
Q
What is differentiation?
A
The process where cells become specialised for a particular job
Differentiation occurs during the development of multicellular organisms
5
Q
What does glandular tissue do?
A
It makes and secretes chemicals like enzymes and hormones.
6
Q
What does epithelial tissue do?
A
Covers some parts of the body
E.g. the outside and inside of the stomach
7
Q
What does muscular tissue do?
A
Contracts to move whatever it is attached to.
8
Q
What is an enzyme?
What is a catalyst?
A
An enzyme is a biological catalyst made up of protein, that provides an alternative reaction pathway by lowering the activation energy.
A catalyst is a substance which speeds up a reaction, without being changed or used up.
9
Q
Why do enzymes usually only catalyse one specific reaction?
A
Every enzyme has an active site with a unique 3D shape, that the substrate fits into.
If the shape of the substrate does not match with the enzyme’s active site there will be no reaction.
10
Q
Why do enzymes have an optimum temperature and pH?
A
A higher temperature increases the rate. If it is too hot, some of the bonds holding the enzyme together will break. The shape of the active site would change, meaning the substrate unable to fit and the enzyme is denatured.
The ph interferes with the bonds holding the enzyme together. When it is not at its optimum, the shape of the active site changes and the enzyme denatures.
11
Q
What is the equation for rate of reaction?
A
1000 ÷ time
12
Q
What is bile?
A
Bile is an alkali produced in the liver, and stored in the gal bladder before it is released into the small intestine.
13
Q
What does bile do?
A
1) Bile neutralises the hydrochloric acid in the stomach, so the enzymes in the small intestine work properly.
2) Bile emulsifies (breaks down) fats, giving a larger surface area for the enzyme lipase. This speeds up digestion.
14
Q
What is protease? Where is produced?
A
An enzyme that breaks down protein into amino acids.
. Small intestine
. Pancreas
. Stomach
15
Q
What is lipase? Where is produced?
A
An enzyme that breaks down lipids into glycerol and fatty acids.
. Small intestine
. Pancreas
16
Q
What is amylase? Where is produced?
A
A type of enzyme, that breaks down starch into simple sugars.
It is an example of a carbohydrase.
. Small intestine
. Pancreas
. Salivary glands
17
Q
How to test for starch?
A
Add iodine solution directly to the substance to be tested (in solid or liquid form)
18
Q
If the starch test has positive results what would the colour change be?
A
Orange to blue/black
19
Q
How to test for protein?
A
Add biuret’s solution to the solution/suspension to be tested
20
Q
If the protein test has positive results what would the colour change be?
A
Reagent blue to purple
21
Q
How to test for lipids?
A
- Add ethanol solution
- Shake throughly
- Add water
22
Q
If the lipids test has positive results what would the colour change be?
A
Clear to cloudy
23
Q
How to test for sugar?
A
- Add Benedict’s solution
- Heat water, look for colour change
24
Q
If the sugar test has positive results what would the colour change be?
A
Blue to brick red
25
How do you prepare the food sample for a food test?
1. **Break up** the piece of food using a **pestle and mortar**
2. Transfer it to **beaker** and add **distilled water**
3. Give the mixture a **stir** with a glass rod to **dissolve** some of the food
4. **Filter** the solution using a funnel lined with filter paper to **get rid** of the **solid** bits of food
26
The lungs are in the thorax. What is the thorax?
It is the top part of your body and separated from the lower part of your body by the diaphragm.
27
What is the trachea? And its function?
It is the windpipe that connects the mouth and nose to the lungs
28
What is the function of the ribs?
. Protect lungs
. Moves to increase volume
29
What is the function of intercostal muscles?
Contract and relax to **move ribs**
30
What is the function of the bronchus?
Connect trachea to bronchioles
31
What are alveoli? And what is their function?
An alveolus is a little air sac surrounded by a network of blood capillaries.
They are the site of gas exchange.
32
What is the function of bronchioles?
Connect bronchus to alveoli
33
What is the function of the diaphragm?
Contract and relax to change volume of lungs
34
What is gas exchange?
Supplying body cells with **oxygen** for respiration
And removing **carbon dioxide** from the blood
*Occurs in the lungs*
35
What is ventilation?
Breathing - moving air into and out of the lungs (exhaling)
36
What is the respiratory system?
The system of organs and structures in which gas exchange takes place
37
How are alveoli adapted for quick diffusion?
Good blood supply - maintains steep concentration gradient
Thin walls - shorter distance for gases to travel
Moist surface area - gases dissolve more easily
38
What is emphysema?
**chronic** (long-term) **obstructive pulmonary** (lungs) **disease**
39
How does emphysema occur?
What usually causes emphysema?
Alveoli becomes inflamed and damaged - the **walls of the alveoli break down** due to loss of surface area and elasticity.
It can be caused by smoking.
40
What are the symptoms of emphysema?
. Shortness of breath
. Tiredness
. Trouble coughing
41
What does the circulatory system do?
It carries food and oxygen (through blood) to every cell in the body.
It also carries waste products to where they can be removed from the body.
42
Fill in the gaps:
Deoxygenated blood enters the **?** atrium through the **??**. The deoxygenated blood flows through the valves, to the **??**. Then the walls contract forcing the deoxygenated blood to **?** the heart through the **??** to the lungs. Oxygen diffuses from the **?** into the blood making it oxygenated blood. Through the **??**, the oxygenated blood from the **?** enters the heart. The oxygenated blood flows from the **?** atrium to the **??**. Then to the aorta and then gets pumped around the **?**.
Deoxygenated blood enters the **right** atrium through the **vena cava**. The deoxygenated blood flows through the valves, to the **right ventricle**. Then the walls contract forcing the deoxygenated blood to **leave** the heart through the **pulmonary artery** to the lungs. Oxygen diffuses from the **alveoli** into the blood making it oxygenated blood. Through the **pulmonary vein**, the oxygenated blood from the **lungs** enters the heart. The oxygenated blood flows from the **left** atrium to the **left ventricle**. Then to the aorta and then gets pumped around the **body**.
43
What does the double circulatory system mean?
There are two pumps
. The right side pumps deoxygenated blood to the lungs
. The left side pumps oxygenated blood to the body
44
What are the four chambers of the heart?
Why are there valves in each side?
Right atrium
Right ventricle
Left atrium
Left ventricle
The valves stop the blood from flowing backwards.
45
What is the function of arteries?
How are they adapted for this?
Transport deoxygenated blood away from the heart under high pressure.
Have thick elastic walls to withstand the pressure
And a small lumen
46
What are walls of the ventricles thicker than walls of atria?
Ventricles pump blood out of the heart so need to generate high pressure
47
Why is the left ventricle wall thicker than the right ventricle wall?
The left ventricle pumps blood to the entire body, not just the lungs.
48
Why are there coronary arteries on the outside of the heart?
They supply the heart with oxygenated blood
49
How does the heart maintain a regular resting heart rate?
The heart has 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**.
50
What is an artificial pacemaker? Why is it used?
An electrical device that is implanted under the skin and has a wire going to the heart.
It is used to correct irregularities in the heart rate.
51
What is coronary heart disease?
Layers of **fatty material** build up inside the coronary arteries and harden to form **plaque (atheroma)**
This **narrows** the arteries and **reduces the flow of blood,** resulting in a lack of oxygen for the heart muscle.
52
Why might coronary heart disease occur?
Too much cholesterol and saturated fat
53
What symptoms can coronary heart disease cause?
. Angina - chest pain when exercising
. Myocardial infraction - heart attacks
54
What are treatments of coronary heart disease?
. Stents
. Statins 💊
. Bypass surgery
55
What is bypass surgery?
1. A section of a vein taken
2. It is used to form a diversion around the area of the heart where the coronary artery is blocked
. Needs general anaesthetic
. 3 month recovery
56
What are stents?
Wire mesh tubes
Used in an angioplasty
57
What are statins? And side effects?
Drugs, that are usually taken for the rest of their life, prescribed to **reduce high cholesterol levels** in the bloodstream which **slows down the rate of fatty deposits forming**.
The effect of statins isn’t instant.
*Potential negative side effects- headaches, memory loss, kidney failure, and liver damage.
However some studies suggest that statins may also help prevent other diseases.*
58
What is angioplasty?
1. Stent inserted at the same time as balloon catheter
2. Expands when balloon is inflated
3. Balloon is removed
4. Stent left permanently
. Takes 1-2 hours
. 1 week recovery
59
What is health?
The state of complete physical, mental and social wellbeing (more than just the absence of disease).
60
What is disease?
A **disorder** which affects all or part of an organism.
61
Explain risk factors that can directly cause a disease
**Smoking** causes cardiovascular disease, lung disease, and lung cancer.
**It damages the walls of arteries and the cells in the lining in the lungs.**
**Obesity** causes type 2 diabetes.
**It makes the body less resistant to insulin, so it struggles to control the concentration of glucose in the blood.**
**Drinking too much alcohol** causes liver disease and affects brain function.
**It damages nerve cells in brain, causing the brain to lose volume.**
62
What are communicable diseases?
Diseases that **spread** from person to person and are **caused by pathogens** (micro organisms which cause disease) like bacteria.
Sometimes called infectious diseases.
63
What are non-communicable diseases?
Diseases that do not spread. They generally get worse over time (eg. Cancer).
64
What is the human cost of non-communicable diseases?
What is the financial cost of non-communicable diseases?
Lower quality of life or shorter life span. Affects patients and loved ones too.
Cost of NHS research and treatment is huge. Families may need to move or adapt their home for the person. If the person has to give up work or dies, the family income will decrease. Reduction in the number of people working can affect the country’s economy.
65
What is cancer?
A tumour, as the result of changes in cells that lead to uncontrollable growth and division.
66
What does benign mean?
When the tumour (un cancerous) keeps growing in one place until there’s no more room.
It isn’t normally dangerous.
67
What does malignant mean?
The tumour grows and migrates to neighbouring healthy tissues, when the cells break off and travel through the bloodstream. It can form secondary tumours.
Malignant tumours can be fatal as they are cancerous.
68
Explain risk factors that can increase the chance of cancer
**Smoking** is linked to lung, mouth, bowel, stomach, and cervical cancer.
**Obesity** is linked to bowel, liver, and kidney cancer.
**UV exposure** is linked to skin cancer.
**Viral infection** has been shown to increase the chances of developing certain types of cancer.
Viruses can be spread through sharing needles or unprotected sex.
69
What is an example of a risk factor associated with genes?
You can inherit faulty genes that make you more susceptible to cancer.
For example, mutations in the BRCA genes are linked to increased chances of developing breast and ovarian cancer.
70
How can cancer be treated?
**Chemotherapy:** drugs are used to kill cancer cells
**Radiotherapy:** x-rays are used to kill cancer cells
71
What are some side effects when treating cancer?
As cancer cells and healthy cells cannot be distinguished, nearby cells are killed too.
This makes the patient weak and tired, often resulting in hair loss.
72
What is the order of the digestive system?
Mouth
Salivary glands
Pharynx
Oesophagus
Stomach
Small intestine
Large intestine
Rectum
Anus
73
What is the function of the mouth?
Mechanically breaks down food particles
74
What is the function of the salivary glands?
Saliva moistures and lubricates the food
75
What is the function of the pharynx?
Swallow
76
What is the function of the oesophagus?
Transport food to stomach
77
What is the function of the stomach?
Stores and churns food
78
What is the function of the small intestine?
Absorb digested food into blood
79
What is the function of the large intestine?
1) Reabsorb water and ions
2) Form and store faeces
80
What is the function of the rectum?
Store and expel faeces
81
What is the function of the anus?
Opening for elimination of faeces
82
What is hydrochloric acid? And what does it do?
Stomach acid which activates enzymes, breaks up food, and kills germs.
83
What types of tissue is a plant made up of?
Epidermal tissue
Palisade mesophyll tissue
Spongy mesophyll tissue
Meristem tissue
Phloem tissue
Xylem tissue
84
What is the epidermal tissue?
**Function:** covers the whole plant
**Adaptations:**
- Has a **waxy cuticle** to reduce water loss through evaporation
- The upper epidermis of the leaf is **transparent** so light can pass through to the palisade layer
- The lower epidermis has **stomata** for diffusion
85
What is the palisade mesophyll tissue?
**Function:** Site of photosynthesis
**Adaptations:**
- Has lots of **chloroplasts** (they can get lots of sunlight for photosynthesis as they are at the top of the leaf)
86
What is the spongy mesophyll tissue?
**Function:** diffusion
**Adaptations:**
- Has lots of big air spaces to allow gases to diffuse in and out of cells
87
What is the meristem tissue?
**Function:** Differentiate into different types of plant cells
Found at the growing tips of shoots and roots.
88
What is translocation?
**When food substances made in the leaves** (mainly dissolved sugars) **are transported to the rest of the plant** (for immediate use or for storage).
The transport goes in both directions.
89
How do phloem tubes allow translocation to occur?
Phloem tubes are made up of columns of **elongated living cells** with small pores in the end walls, which allows cell sap to flow through.
90
What is transpiration?
The movement of water from the roots, through the xylem and out of the leaves is called the transpiration stream.
91
Why does transpiration occur?
Transpiration is a **side-effect of** the way leaves are adapted for **photosynthesis**.
Leaves need to have **stomata** to exchange gases easily. But this means there is **more water inside the plant than in the air outside**. So, the water escapes from the leaves through the stomata by diffusion.
92
Why is there a constant transpiration stream of water through the plant?
The evaporation creates a slight shortage of water in the leaf, so more water is drawn up from the rest of the plant through the xylem vessels. This means more water is drawn up from the roots.
93
How is transpiration rate affected by temperature?
When it is warm the water particles have more energy to evaporate and diffuse out of the stomata.
Therefore, as temperature increases the rate of transpiration increases.
94
How is transpiration rate affected by air flow?
When air flow is poor, the water vapour surrounding the leaf doesn’t get moved away. If there is a high concentration of water particles outside the leaf as well as inside it, diffusion will be slower.
Therefore, as air flow increases the rate of transpiration increases.
95
How is transpiration rate affected by humidity?
If the air is humid there is already a lot of water. So there isn’t much difference between the concentration of water in the air and the leaf. Diffusion happens faster if the concentration gradient is steeper.
Therefore, as humidity decreases the rate of transpiration increases.
96
How is transpiration rate affected by light intensity?
As it gets darker, the stomata begin to close because photosynthesis cannot occur. When the stomata are closed, very little water can escape.
Therefore, as light intensity increases the rate of transpiration increases.
97
How are guard cells adapted to open and close stomata?
*Guard cells are adapted for gas exchange and controlling water loss within a leaf.*
- **Kidney shape**
- Guard cells become **turgid** when there is **lots of water** in the plant, making the stomata **open** and *allow gas exchange for photosynthesis.*
- Guard cells become **flaccid** when there is **less water** in the plant, making the stomata **close** and *stopping too much water vapour from escaping.*
98
Why are more stomata usually found on the underside of leaves than on the top?
The lower surface is shaded and cooler - so less water is lost through the stomata than if they were on the upper surface.
