Biol1 AQA Flashcards

In homogenisation, why is an ice-cold solution used?
To reduce enzyme activity.
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In homogenisation, why is the solution isotonic?
To stop the organelles from bursting and to stop osmosis.
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People with dis functioning mitochondria can't exercise for long, why?
Mitochondria are the site of aerobic respiration, and mitochondria produce ATP. This ATP is required for muscles to contract.
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What is the role of the sino atrial node?
Act as a pacemaker and to send out electrical impulses.
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What is the Benedict's test?
A test for reducing sugars, which is blue, which you add to a sample and heat it. If the solution contains a reducing sugar it turns brick red, due to the formation of a red precipitate.
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Name a way in which a pathogen can cause disease when it enters the body of their host.
Produce toxins and release them into the body.
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Name a way in which a pathogen can cause disease when it enters the body of their host.
Cell damage - rupture the cell to release nutrients, break down the nutrients and replicate inside the cell to bust it.
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What is a vaccine?
Contains weakened microorganisms to stimulate the production of antibodies.
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Name some factors to consider when doing a trial.
Age, sex, health, ethnicity.
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Name a structure that suggests an organism is eukaryotic.
Nucleus.
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Apart from reduced elasticity, explain how changes to the lung tissue reduce the efficiency of gas exchange.
The alveolar walls thicken, tissue becomes scarred and fibrous, there is a longer diffusion pathway and a reduced surface area.
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Describe the role of the enzymes of the digestive system in the complete breakdown of starch.
Amylase; starch to maltose. Maltase; maltose to glucose. Hydrolysis of glycosidic bond.
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Describe the processes involved in the absorption of the products of starch digestion.
Glucose moves in with sodium via a carrier protein. Sodium is removed by the sodium potassium pump into the blood. This maintains a low concentration of sodium. Glucose moves into the blood by facilitated diffusion.
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What is atheroma?
A build up of fatty material in the artery wall.
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How does a blood clot lead to a myocardial infarction?
A blood clot forms in the coronary artery, where less oxygen can then be carried in the blood to reach the heart, therefore the heart stops respiring.
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Maltose is hydrolysed by what into what?
Maltase into glucose and glucose.
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Sucrose is hydrolysed by what into what?
Sucrase into glucose and fructose.
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Lactose is hydrolysed by what into what?
Lactase into glucose and galactose.
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Phagocytes and lysosomes.
A phagocyte will engulf a pathogen, the pathogen is then enclosed in a vacuole. Lysosomes have enzymes which digest proteins and the microorganism.
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Oral rehydration systems.
ORS - lowers the water potential and increases the uptake of sodium ions by co-transport. The solution also makes water move out of the intestine by osmosis.
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Transmission electron microscopes.
Must be carried out in a vacuum. Produce black and white images. Are high resolution. Small objects can be seen. Shorter electron wavelength. Can't look at living things. Specimen can only be very thin.
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Lactose + water > glucose + galactose. Name the type of chemical reaction shown in this equation.
Hydrolysis.
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Describe how you could use the biuret test to distinguish a solution of the enzyme, lactase from a solution of lactose.
Presence of the lactase will give a purple solution result.
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Describe the path by which oxygen goes from an alveolus to the blood.
Oxygen diffuses through the alvelous epithelium, into the epithelium of the cappilaries surrounding the alveoli and into the blood.
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Explain why people with miner's lung have a lower concentration of oxygen in their blood.
There is a longer diffusion pathway.
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Describe how ventilation helps to maintain a difference in oxygen concentration.
Ventilation brings in the blood with a higher conc of oxygen and removes the air with a lower conc of oxygen.
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Give another way, aside from ventilation, which helps to maintain a difference in oxygen concentration.
Circulation of the blood.
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Explain how mitochondria help to absorb the products of digestion.
Mitochondria are the site of aerobic respiration, and produce ATP.
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The cardiac cycle is controlled by the sinoatrial node and the atrioventricular node, describe how.
The SAn acts as a pace maker and sends out electrical impulses to cause atrial contractions. The AVN delays the impulse allowing atria to empty before contracting, then sends the impulse down the Bundle of His causing the contraction.
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Name three structures which are found in prokaryotic cells and not in eukaryotic cells.
Small ribosomes, plasmids, flagellum.
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ORS: Why must the water be boiled to be used?
To destroy any bacteria.
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ORS:These mixtures contain glucose, name another substance that must be present in the mixture.
Sodium ions.
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What is the equation to calculate pulmonary ventilation?
Pulmonary ventilation = tidal volume X breathing rate
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Name the type of bond that joins amino acids together in a polypeptide.
Peptide.
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Why are cells homogenised?
To release the cell contents.
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Why are cells filtered after homogenisation?
To remove debris.
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What is a HPV antigen?
A protein causing an immune response.
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A vaccine can be used to produce immunity to HPV. Describe how memory cells are important in this process.
Memory cells are produced, when the person comes into contact again a secondary response occurs quickly and destroys the virus.
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Suggest why an increased lumen diameter is linked to a reduced risk of coronary heart disease.
Less chance of having high blood pressure, blood clots and atheroma forming.
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Many different substances enter and leave a cell by crossing its cell surface membrane. Describe how.
Small substances move across the phospholipid bi-layer, simple diffusion from high conc to low conc, water moves by osmosis, actie transport against conc gradient and facilitated diffusion.
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Give one advantage of a scanning electron microscope rather than a transmission electron microscope
Can have 3D images
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Describe the induced fir model of enzyme action
The shape of the active site changes, and this change in enzyme allows an enzyme substrate complex to form
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Describe one way that the lock and key model is different from the induced fit model
The active site shape does not change in lock and key
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Explain, in terms of pressure, why the semilunar valves open
Pressure is greater below the valve
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What is an unsaturated fatty acid?
Double bonds between carbon
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Name the type of bond between two fatty acids
Glycosidic
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Pulmonary tuberculosis is a disease of the lungs, describe the transmission and course of infection of pt
Bacteria are transmitted in aerosol, they are then engulfed by phagocytes and enclosed in a nodule. Bacteria can't replicate. If immunosupressed, bacteria activate and destroy alveoli leading to fibrosis and less diffusion
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Emphysema is another disease of the lungs. People with emphysema may feel weak and tired. Explain why
Alveoli break down, so there is less surface area and a loss of elastin. Alveoli cannot recoil, so there is a reduced diffusion gradient. Less oxygen enters the blood so less respiration occurs
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Other cards in this set

Card 2

Front

In homogenisation, why is the solution isotonic?

Back

To stop the organelles from bursting and to stop osmosis.

Card 3

Front

People with dis functioning mitochondria can't exercise for long, why?

Back

Preview of the front of card 3

Card 4

Front

What is the role of the sino atrial node?

Back

Preview of the front of card 4

Card 5

Front

What is the Benedict's test?

Back

Preview of the front of card 5
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trybreathing

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very useful thanks :)

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