Organisation Flashcards

1
Q

What are cells?

A

Cells are the basic unit of life - they make up all living things

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2
Q

What are tissues?

A

A tissue is a group of specialised cells with a similar structure and function. They can be made of more than one type of cell. Examples include muscular tissue or epithelial tissue.

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3
Q

What are organs?

A

Organs are formed from a number of different tissues, working together to produce a specific function. An examples is the stomach, which has muscular tissue and epithelial tissue.

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4
Q

What are organ systems?

A

Organs are organised into organ systems, which work together to perform a certain function. The stomach is part of the digestive system, along with organs such as the liver and small intestine.

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5
Q

Which glands produce digestive juices to break down food?

A

Salivary glands and the pancreas

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6
Q

What function does stomach acid serve?

A

The stomach produces hydrochloric acid to kill bacteria and to provide the optimum pH for the protease enzyme to work.

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7
Q

Where are small soluble molecules absorbed in the digestive system?

A

The small intestine.

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8
Q

What organ produces bile and where is it stored?

A

The liver produces bile and it is stored in the gall bladder

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9
Q

What does the large intestine do?

A

Absorbs water from undigested food to produce faeces. This passes out of your body through the rectum and anus.

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10
Q

What are enzymes?

A

Proteins that are biological catalysts (a substance that increases the rate of reaction without being used up)

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11
Q

How do enzymes work?

A

Each enzyme has its own uniquely shaped active site where the substrate binds. They can both break up large molecules and join small ones.

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12
Q

What factors affect enzyme function?

A

pH and temperature.

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13
Q

How does temperature affect enzymes?

A

○ The rate of reaction increases with an increase in temperature up to this optimum, but above this temperature it rapidly decreases and eventually the reaction stops.
○ When the temperature becomes too hot, the bonds in the structure will break
○ This changes the shape of the active site, so the substrate can no longer fit in
○ The enzyme is said to be denatured and can no longer work

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14
Q

What do carbohydrases do?

A

convert carbohydrates into simple sugars. Example: Amylase - breaks starch down to maltose

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15
Q

What do proteases do?

A

convert proteins into amino acids. Example: pepsin which is produced in the stomach

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16
Q

What do lipases do?

A

convert lipids into fatty acids and glycerol.

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17
Q

What is the test for sugars?

A

Benedict’s test for sugars (turns brick red)

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18
Q

What is the test for starch?

A

Iodine test for starch (turns blue-black)

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19
Q

What is the test for protein?

A

Biuret test for protein (turns purple)

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20
Q

What is the function of bile?

A

Neutralises stomach acid and emulsifies fat in to small droplets, so there is a larger surface area for lipases to act on.

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21
Q

Is the human circulatory system double or single?

A

Double
1: Deoxygenated blood flows into the right atrium and then into the right ventricle
which pumps it to the lungs to undergo gaseous exchange
2: Oxygenated blood flows into the left atrium and then into the left ventricle
which pumps oxygenated blood around the body”

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22
Q

How many chambers are in the heart?

A

Four - two atria and two ventricles

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23
Q

What are the function of valves?

A

make sure blood does not flow backwards

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24
Q

What vessels supply blood to the heart?

A

Coronary arteries

25
Q

Describe the flow of blood in the heart.

A
  1. Blood flows into the right atrium through the vena cava
  2. The atria contract forcing the blood into the ventricles.
  3. The ventricles then contract, pushing the blood in the right ventricle into the pulmonary artery to be taken to the lungs
  4. Oxygenated blood returns to the left atrium via the pulmonary vein
  5. the atrium contracts and blood rushes into the left ventricle
    Blood exits the left ventricle via the aorta to the rest of the bloody
26
Q

Where are pacemaker cells found?

A

The right atrium.

27
Q

Why are artificial pacemakers used?

A

An artificial pacemaker can be used if the individual has an irregular heartbeat. It is an electrical device that produces a signal causing the heart to beat at a normal speed.

28
Q

What do arteries do?

A

Carry blood AWAY from the heart

29
Q

Describe the structure of arteries.

A

● Layers of muscle in the walls make them strong

● Elastic fibres allow them to stretch

30
Q

What do veins do?

A

Carry blood TOWARDS the heart

31
Q

Describe the structure of veins.

A

● The lumen (the actual tube in which blood flows through) is wide to allow the low pressure blood to flow through
● They have valves to ensure the blood flows in the right direction

32
Q

What do capillaries do?

A

Capillaries allow the blood to flow very close to cells to enable substances to move between them

33
Q

How are capillaries specialised for their function?

A

● One cell thick walls create a short diffusion pathway

● Permeable walls so substances can move across them

34
Q

Formula for rate of blood flow.

A

volume of blood/number of minutes.

35
Q

What makes up the gas exchange system?

A

Trachea, intercostal muscles, bronchi, bronchioles, alveoli and diaphragm.

36
Q

Describe ventilation.

A
  1. The ribcage moves up and out and the diaphragm moves down causing the volume of the chest to increase.
  2. Increased volume results in lower pressure.
  3. Air is drawn into the chest as air moves from areas high pressure (the environment) to low pressure (the lungs).
  4. The opposite happens when exhaling.
37
Q

Describe gas exchange.

A
  1. Upon inhalation, the alveoli fill with oxygen.
  2. The blood in the capillaries surrounding the alveoli is deoxygenated (it has come from the pulmonary vein). It has lots of carbon dioxide as this is a product of respiration.
  3. Oxygen diffuses down its concentration gradient into the capillary bloodstream, which has a low concentration of oxygen.
  4. Carbon dioxide diffuses down its concentration gradient from the blood to the alveoli
38
Q

How are alveoli adapted?

A

● They are very small and arranged in clusters, creating a large surface area for diffusion to take place over
● The capillaries provide a large blood supply, maintaining the concentration gradient
● The walls of the alveoli are very thin, meaning there is a short diffusion pathway

39
Q

Formula for breathing rate.

A

number of breaths/number of minutes

40
Q

What are the constituents of blood?

A

Plasma, red blood cells, white blood cells, platelets

41
Q

What can be found in plasma?

A

red blood cells, white blood cells, platelets, glucose, amino acids, carbon dioxide, urea, hormones,
proteins, antibodies and antitoxins

42
Q

How are red blood cells adapted to carry oxygen?

A

Biconcave shape, no nucleus, contain haemoglobin that binds oxygen.

43
Q

What are 3 ways white blood cells can defend against pathogens?

A

Produce antibodies, engulf/digest microorganisms, produce anti-toxins to neutralise toxins from pathogens

44
Q

What do platelets do?

A

Help blod clots to form at the site of a wound, a scab forms as a barrier against pathogen entry at the site.

45
Q

What are non-communicable diseases?

A

Non-infectious e.g. coronary heart disease

46
Q

What is coronary heart disease?

A

when the coronary arteries that provide blood to the heart become blocked with the build up of fatty material. This results in less blood flowing to the heart, reducing its oxygen supply. This may lead to a heart attack.

47
Q

What are some solutions to coronary heart disease?

A

Stents and statins

48
Q

How do statins work?

A

Decrease levels of LDL (bad) cholesterol and increase levels of HDL (good) cholesterol to prevent blockage of coronary arteries.

49
Q

What are two types of tumours?

A

Benign and malignant (cancerous)

50
Q

What are some lifestyle risk factors for cancer?

A

Smoking, obesity, UV light, viral infection

51
Q

What is the function of a waxy cuticle?

A

Helps to reduce water loss by evaporation, as the waxy cuticle prevents water from moving out.

52
Q

What do chloroplasts do?

A

Where photosynthesis takes place, contains chlrophyll which is a green pigment that captures UV light

53
Q

What is the meristem?

A

Plant stem cells - cells in the meristem can differentiate in to any type of plant tissue

54
Q

What does the phloem do?

A

Food substances can be moved in both directions, from the leaves where they are made for use, or from storage (underground) to parts of the plant that need it.

55
Q

What does the xylem do?

A

Allows the movement of water and mineral ions from the roots to the stem and leaves, where it evaporates and leaves the plant. This called the transpiration stream.

56
Q

What factors effect rate of transpiration?

A

Temperature, humidity, air movement, light intensity

57
Q

What cells open and close the stomata?

A

Guard cells.

58
Q

Where are stomata mostly found and why?

A

More stomata are found on the bottom of the leaf, allowing gases to be exchanged whilst minimising water loss by evaporation as the lower surface is shaded and cooler.