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MBH - Diet and Food
OCR A level Biology F212 Diet and Food Production
| Question | Answer |
|---|---|
| What is a balanced diet? | One that contains all the nutrients required for health in appropriate proportions. |
| How does malnutrition occur? | Malnutrition, including obesity, is caused by an unbalanced diet. |
| How is obesity caused? | By consuming too much energy, which is deposited as fat in the adipose tissues. |
| What happens in obesity? | Excessive fat deposition impairs health, and is usually defines as when a person has body mass index of 30 or over. |
| What is coronary heart disease? | The narrowing of coronary arteries, reducing the blood flow to cardiac muscle, so less oxygen can reach these cells for respiration. |
| How does salt increase the risk of CHD? | Decreases water potential of blood, increased water in blood increases diastolic BP, which can cause damage to arteries. |
| What type of fat is most harmful? How do fats increase CHD risk? | Animal fat. Increase blood cholesterol levels. |
| What is cholesterol? | Essential, found in cell membranes and skin, used to make sex hormones and bile. Insoluble in water, so transported as lipoproteins. 2 types: high density lipoprotein and low density lipoprotein. |
| What is high density lipoprotein? | Combination of unsaturated fats, cholesterol and protein. |
| What does HDL do? | Takes cholesterol from tissues to liver. Binds to receptor sites on liver cells. Cholesterol used to make bile or broken down to be excreted. |
| What is low density lipoprotein? | Combination of saturated fats, cholesterol and protein. |
| What does LDL do? | Takes cholesterol from liver to tissues. Binds to receptor sites on cell membranes. High blood concentration causes deposition in artery walls. |
| What do different types of fat do to LDL receptors? | Saturated fats reduce activity of LDL receptors, so more remains in the blood. Polyunsaturated and monounsaturated fats increase activity of LDL receptors so less remains in blood. |
| Why do we depend on plants for food? | They produce glucose and oxygen by photosynthesis, using carbon dioxide and water, and are therefore the basis of all food chains. |
| What is selective breeding? | The application of selection pressures by human intervention. |
| What are the steps of selective breeding? | Individuals with desired characteristics selected for breeding. Best offspring chosen and selected for breeding. Over several generations, desired alleles increase in frequency. |
| Why would we selectively breed? | Improved growth rate / standardized size. Improved productivity. Increased resistance to disease / pests. |
| Selective breeding in plants – first step? | Parent plants selected for desired characteristics. |
| Second step? | Designate one as male and one as female. |
| Third step? | Remove stamens from female plant to prevent self pollination. |
| Fourth step? | Keep flowers of female plant covered to prevent unwanted pollination. |
| Fifth step? | Pollinate female plant and allow fertilisation and seed development. |
| Sixth step? | Plant seeds and inspect offspring. |
| Seventh step? | Select from offspring and repeat for many generations. |
| Outline selective breeding in animals? | Select animals with desired characteristics, allow to reproduce or artificially inseminate. Offspring selected with best characteristics, repeat. Repeat for many generations. |
| Why is fertiliser used for plants? | Adds mineral ions to the soil e.g. nitrates, potassium and phosphate, increasing the growth rate and size of crop. |
| Why are pesticides and fungicides used with plants and animals? | The pests and fungus could damage the plants and animals, so killing them helps to prevent this damage. |
| Why are antibiotics used on farm animals? | Intensive farming has increased disease transmission, so antibiotics are used to treat infected animals (and sometimes as a preventative measure), because disease can slow growth and impair reproduction. |
| What are the advantages of using microorganisms to make food? | Low fat; fast, easily variable production; high protein; higher than meat in dietary fibre; no animal welfare issues; can use waste products from other industries; climate independent; less waste. |
| What are the disadvantages of using microorganisms to make food? | Do we want to eat fungus protein made of waste products? Expensive. Taste? |
| How does salting and adding sugar preserve food? | Dehydrates (loss of water by osmosis) so microbes cannot survive. |
| How does pickling preserve food? | Low pH denatures the enzymes of the micro-organisms. |
| How does freezing preserve food? | Inactivates enzymes of microorganisms, and slows or stops their reproduction. |
| How does heat treatment preserve food? | Kills microorganisms and denatures enzymes. |
| How does irradiation preserve food? | Kills bacteria, mold and insect pests, reduces ripening of fruit. |
Created by:
emm142
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