How is the structure of triglycerides related to their properties?
They have a high ratio of carbon-hydrogen bonds to carbon atoms; they have a low mass to energy ratio; they are large and non-polar; and they have a high ratio of hydrogen to oxygen atoms.
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How does having a high ratio of carbon-hydrogen bonds to carbon atoms make triglycerides a good store of energy?
The carbon-hydrogen bonds are energy-storing and so having a lot of them makes them a good source of energy.
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Why does having a low mass to energy ratio make triglycerides a good storage molecule?
A lot of energy can be stored in a small volume. This is especially beneficial to animals as it reduces the mass they have to carry as they move around.
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How does being large, non-polar molecules make triglycerides a good storage molecule?
Being large and non-polar, they are insoluble in water. As a result, their storage does not affect osmosis in cells or the water potential of them.
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Why does having a high ratio of hydrogen to oxygen atoms make triglycerides a good storage molecule?
They release water when oxidised and therefore provide an important source of water, especially for organisms living in dry deserts.
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How is the structure of phospholipids related to their properties?
They are polar; they have a hydrophilic head and a hydrophobic tail.
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How does the phospholipid's polarity relate to its properties?
In an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes. As a result, a hydrophobic barrier is formed between the inside and outside of a cell.
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How is the phospholipid's structure related to cell recognition?
The phospholipid structure allows them to form glycolipids by combining with carbohydrates within the cell-surface membrane. These glycolipids are important in cell recognition.
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How does the hydrophilic phosphate molecule relate to the phospholipid's properties?
The hydrophilic heads help to hold the phospholipids at the surface of the cell-surface membrane.
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What is the test for lipids?
You take a dry and grease-free test tube and to 2cm3 of the sample being tested, add 5cm3 of ethanol. Shake the tube thoroughly to dissolve any lipid in the sample, then add 5cm3 of water and shake gently. A cloudy-white colour indicates a lipid.
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Why does the solution turn cloudy if lipids are present?
Any lipid in the sample is finely dispersed in the water to form an emulsion. Light passing through this emulsion is refracted as it passes from oil droplets to water droplets, making it appear cloudy. As a control, repeat the experiment using water.
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How is the substrate molecule held in the active site?
By bonds that temporarily form between certain amino acids of the active site and groups on the substrate molecule.
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What is a limitation of the lock and key model?
The enzyme is considered to be a rigid structure; however, scientists knew that other molecules could bind to enzymes at sites other than the active site, which alters the activity (therefore the shape) of the enzyme. So the enzyme must be flexible.
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Why have our body temperatures evolved to be 37°C?
Although slightly higher temps would increase the metabolic rate slightly, the advantages are offset by the additional energy that would be needed to maintain the higher temp. Other proteins than enzymes may be denatured at higher temps.
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What is the effect of enzyme concentration on the rate of reaction?
As long as there is an excess of substrate, an increase in the amount of enzyme leads to a proportionate increase in the rate of reaction. If however the substrate is limiting, then any increase in enzyme concentration will have no effect on the rate
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What is polarity?
When two poles behave differently
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Other cards in this set
Card 2
Front
How does having a high ratio of carbon-hydrogen bonds to carbon atoms make triglycerides a good store of energy?
Back
The carbon-hydrogen bonds are energy-storing and so having a lot of them makes them a good source of energy.
Card 3
Front
Why does having a low mass to energy ratio make triglycerides a good storage molecule?
Back
Card 4
Front
How does being large, non-polar molecules make triglycerides a good storage molecule?
Back
Card 5
Front
Why does having a high ratio of hydrogen to oxygen atoms make triglycerides a good storage molecule?
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