Organisation Flashcards
Explain the financial impact on the UK economy of the increasing number of people becoming obese.
Increased costs for NHS because they have to pay for medication.
Explain how amylase breaks down starch in terms of the lock and key theory.
Starch (substrate) binds to the active site of the enzyme as the shape of the active site and substrate are complementary so form an enzyme-substrate-complex. A chemical reaction then occurs to release/produce smaller molecules (sugars) and amylase is not used up
Describe the effect of temperature on enzyme activity.
- Initially as temperature increases enzyme activity increases because the enzyme gains kinetic energy and therefore there are more frequent and successful enzyme-substrate collisions
- Optimum temperature is where enzyme activity is the best
- Once temperature gets too high, the enzyme denatures (active site changes shape) so the substrate shape can no longer fit on to enzymes active sites shape meaning the reaction can no longer be catalysed
RPA 3: Explain why at very low and very high temperatures iodine doesn’t become yellow/brown.
Doesn’t become yellow/brown because starch is still present as it hasn’t been broken down so remains blue. At very low temperatures enzymes don’t have enough kinetic energy so fewer enzyme-substrate-complex collisions. At very high temperatures enzymes denature (active site changes shape) so the substrate shape can no longer fit on to the active site meaning reaction can’t be catalysed
Which cell structure in a mesophyll cell is not found in a root hair cell?
Chloroplasts (underground so no light to absorb)
What cells control the rate of water loss?
Guard cells (control the stomata)
What is the term for water being taken up the roots, up the plant and lost from the leaves?
Transpiration stream.
Explain why the rate of water loss is lower at night.
Lower light intensity so stomata is almost completely closed by guard cells (guard cells are light sensitive).
How can you tell a tumour is malignant?
It has spread to other organs through the bloodstream forming secondary tumours and so are cancerous
Explain how a lower number of blood components can cause symptoms of tiredness.
Less RBCs so less haemoglobin to bind to oxygen, so less oxygen transported around the body to cells. Less (aerobic) respiration so less energy released.
Explain how a lower number of blood components can cause symptoms of frequent infections.
Less WBCs so fewer antibodies and antitoxins produced and less phagocytosis (weaker immune system) so less pathogens killed.
Explain how a lower number of blood components can cause symptoms of excessive bleeding.
Less platelets so blood does not clot as easily - cell fragments are sticky.
Explain why a tumour blocking the gall bladder from the small intestine affects fat digestion.
Less bile reaching the small intestine as the gall bladder stores bile. Less emulsification of fats so a smaller surface area for lipase enzymes to break down. No bile also means pH of small intestine is not neutralised (bile is alkaline) so lipase is not at its optimum pH to break down fats. Lipids broken down less efficiently
Name 3 chemical substances carried by the plasma.
- amino acids
- glucose
- hormones
Describe how white blood cells aid infections.
A part of the immune system. Can produce antitoxins which neutralise/counteract toxins released by bacteria. Can also produce antibodies which are proteins specific to a pathogen as complementary to its antigen protein so will kill the pathogens. Can also engulf and kill pathogens by phagocytosis.
Explain the lock and key theory of enzyme action.
Enzymes active site shape is complementary so the substrates shape fits onto it. They bind and the substrate is broken down (as an enzyme-substrate-complex is formed) where a chemical reaction occurs. Products will be released whilst the enzyme remains unchanged.
Explain why enzymes catalyse specific reactions.
Active sites have a specific shape complementary to one specific substrates shape.
RPA 4: describe how a student can carry out a test for glucose.
Add Benedict’s solution to a test tube with sample and gently heat in a water bath. If glucose is present solution will turn from blue to brick red/orange/green.
Explain why a plant in light contains both glucose and starch.
Glucose produced from photosynthesis. Excess glucose converted to starch for storage as starch is insoluble.