Diet and Food Production Flashcards
Define the term balanced diet.
A diet that contains all of the nutrients required for health and growth in the correct proportions.
Explain malnutrition (reference obesity).
Malnutrition is caused by an unbalanced diet.
Obesity is caused by consuming too much energy; excess energy is deposited as fat in the adipose tissues.
Obesity is the condition in which excess fat deposition impairs health and it usually defined when a person has a BMI of 30 or over.
How could diet be linked to CHD?
Excess salt in the diet decreases the water potential of the blood. As a result, more water is held in the blood and blood pressure increases. This leads to hypertension, which can damage the inner lining of the arteries, which is one of the early steps in the process of atherosclerosis.
Saturated fats are accepted to be more harmful than unsaturated fats.
How are cholesterols transported around the body?
In the form of lipoproteins.
What is the effect of high numbers of LDLs on the circulatory system?
LDLs carry cholesterol from the liver to the cells and there are receptors for LDLs on the cells.
LDLs raise blood cholesterol and thus increase deposition of fats and cholesterol under the endothelium of an artery and form atheromas .
What is the effect of high numbers of HDLs on the circulatory system?
HDLs carry cholesterol from tissues to the liver and there are receptors for HDLs on liver cells.
HDLs lower blood cholesterol and thus reduce deposition of fats and cholesterol and so decrease the formation and risk of atheromas.
What are the effects of saturated fats on the circulatory system?
Saturated fats decrease the activity of LDL receptors, so as the concentration of LDL in the blood rises; less is removed from the blood, resulting in higher concentrations of LDL in the blood, which are then deposited on the artery walls.
How are humans dependent on plants for food?
Plant carry out photosynthesis to make chemical energy and absorb nutrient from the soil to produce a range of biomolecules. Humans eat both plants and animals who have eaten these plants or other animals who have and thus rely directly and indirectly on plants for nutrition.
How can selective breeding be used to produce crop plants with high yields/ disease and pest resistance or animals with high productivity?
A pair of plants or animals which display the desired characteristics are allowed to reproduce.
The offspring produced are sorted carefully so only those with the best combination of characteristics are allowed to reproduce.
If this careful selection and controlled reproduction continues for many generations, the required characteristic becomes more exaggerated.
What are the disadvantages of selective breeding?
Growth may be too rapid (animals).
Possibility of increase susceptibility to disease.
Can cause inbreeding (animals)
Reduces gene pool/ genetic variation.
How are fertilisers used to increase crop production?
Fertilisers replace minerals in the soil which may have been removed by the previous crops. They contain Nitrate, Phosphate and Potassium. They increase the rate of growth and therefore the yield.
How are pesticides used to increase food production?
Pesticides kill organisms that prey on or cause disease to organisms used for food, improving yield by destroying anything that might prevent high yields i.e crops are sprayed to protect from fungi and sheep are dipped to kill ticks.
How are antibiotics used to increase animal productivity?
Infected animals can be treated with antibiotics to reduce the spread amongst animals that
are intensively farmed in close proximity to each other. Such diseases could reduce the
growth performance of the animals and may impair reproduction.
What are the advantages of using microorganisms to produce food?
Production of protein can be many times faster than that of animal or plant protein.
Production can be increased or decreased according to demand.
No animal welfare issues.
They provide a good source of protein for vegetarians.
The protein contains no animal fat or cholesterol.
Single-cell protein production could be combined with removal of waste products.
What are the disadvantages of using microorganisms to produce food?
Many people may not want to eat fungal protein that has been grown on waste.
The microorganisms are grown in huge fermenters and need to be isolated from the material on which they grow.
The protein has to be purified to ensure it is uncontaminated.
The conditions needed to grow the useful organisms are ideal for pathogenic organisms.
Care needs to be taken to ensure that the culture is not infected.
The protein does not have the taste or texture of traditional protein sources.
