Unit 1 - Biology and Disease (AQA)

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  • Created by: Dalia
  • Created on: 26-01-13 16:21
In cell fractionation, why is the solution cold?
To reduce enzyme activity that might break down the organelles
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In cell fractionation, why is the solution isotonic?
To prevent osmosis occurring so that the cell doesn't shrink or burst
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In cell fractionation, why is the solution buffered?
To maintain a constant pH so the enzymes do not denature
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How would you work out the size of an actual object?
Image/magnification
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Glucose linked to glucose forms...
Maltose
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Glucose linked to fructose forms...
Sucrose
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Glucose linked to galactose forms...
Lactose
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What are the roles of lipids in the plasma membrane?
An energy source, waterproofing, insulation and protection
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What are the functions of phospholipids in the plasma membrane?
Allow lipid-soluble substances to enter and leave the cell, make the membrane flexible and to prevent water-soluble substances entering and leaving the cell
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What are the functions of intrinsic and extrinsic proteins in the plasma membrane?
Provide structural support, act as carriers transporting water-soluble substances across the membrane, allow active transport across the membrane by forming ion channels for sodium/potassium, act as receptors, help cells adhere together
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Diffusion is proportional to...
Surface area x difference in concentration/length of diffusion path
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Facilitated diffusion relies on what?
The inbuilt motion/kinetic energy of diffusing molecules
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What is osmosis?
The passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a partially permeable membrane
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What is active transport?
The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using energy and carrier molecules
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How are prokaryotic cells different to eukaryotic?
No true nucleus, no nucleolus, no chromosones, no membrane-bound organelles, flagellum, capsule, plasmid, circular DNA
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How is cholera transmitted?
Drinking water that is not properly purified, untreated sewer leaks into water courses, food contamination
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What causes diarrhoea?
Damage to the epithelial cells lining the intestine, loss of microvilli due to toxins, excessive secretion of water due to toxins
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In Oral Rehydration Therapy, what does the solution need to contain?
Water, sodium, glucose and potassium
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Why must boiled water be used to make an ORS?
To kill the bacteria
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Why does the alveoli contain elastic fibres?
To allow the alveoli to stretch as they fill with air when breathing in. They then spring out during expiration in order to expel the carbon dioxide-rich air
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The contraction of what leads to expiration?
The internal intercostal muscles
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The contraction of what leads to inspiration?
The external intercostal muscles
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What happens during inspiration?
External intercostal muscles contract/internal relax, ribs pulled upwards and outwards, diaphragm muscles contract, increased volume of thorax reduced lung pressure
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What happens during expiration?
Internal intercostal muscles contract/external relax, ribs move down and in, diaphragm muscles relax, decreased volume of thorax increases lung pressure
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What is the equation for pulmonary ventilation?
pulmonary ventilation = tidal volume x ventilation rate
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What are the risk factors for lung disease?
Smoking, air pollution, genetic make-up, infections, occupation
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Why is the ventricle wall thicker than the atrial wall?
The ventricle has to pump blood all the way around the body
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What happens during diastole?
Atria are relaxed and fill with blood, ventricles are relaxed, SL valves closed, AV valves open
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What happens during atrial systole?
Atria contract to push remaining blood into ventricles, SL valves closed, AV valves open, ventricles remain relaxed
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What happens during ventricular systole?
SL valves open, AV valves close, atria relax, ventricles contract, blood pushed away from heart through pulmonary artery and aorta
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What is the equation for cardiac output?
Cardiac output = stroke volume x heart rate
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How is the cardiac cycle controlled?
SAN acts as a pacemaker, sends electrical impulses through atria causing atria to contract, AVN delays impulses, allows ventricles to fill before they contract, sends impulses through Bundle of His causing ventricular systole
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What is an atheroma?
Fatty deposit in the walls of an artery
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How can an atheroma lead to myocardial infarction?
Causes blood clot, arteries become narrowed and blocked, reduced oxygen levels to heart, heart muscles cannot contract and die
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What happens when an aneurysm bursts?
Haemorrhage and therefore loss of blood to the region of the body supplied by that artery
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Where do B lymphocytes mature?
In the bone marrow
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Where do T lymphocytes mature?
In the thymus gland
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In cell fractionation, why is the cell homogenised?
To release the organelles
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Other cards in this set

Card 2

Front

In cell fractionation, why is the solution isotonic?

Back

To prevent osmosis occurring so that the cell doesn't shrink or burst

Card 3

Front

In cell fractionation, why is the solution buffered?

Back

Preview of the front of card 3

Card 4

Front

How would you work out the size of an actual object?

Back

Preview of the front of card 4

Card 5

Front

Glucose linked to glucose forms...

Back

Preview of the front of card 5
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