1) Food and nutrients.
1. Make a scheme about types of nutrients.
2. Make a scheme of the carbohydrates, explaining types of
carbohydrates, function, food which contains them, and examples of each ones.
Sugars: energy-giving substances found in daily food as pasta,
bread, fruit...
Types:
Simple carbohydrates: sweet, crystalline and soluble in
water.
o Monosaccharides: they are formed by a single
molecule, such as glucose (honey) and fructose (fruit)
o Disaccharides: they are formed by two molecules
joined, such as sucrose (white sugar) and lactose
(milk) types of nutrients biomolecul es carbohydrat es
simple glucose,sucrose...
complex starch, fibre
lipids fats saturated and insaturates membrane lipids regulatory
lipids hormones
proteins aminoacids
vitamins
inorganic molecules
water
Complex carbohydrates: they are neither sweet nor
crystalline. They are formed by many monosaccharides,
such as starch (potatoes and pasta) or fibre (vegetables
as lettuce and asparagus).
3. Make a scheme of the lipids, explaining types of lipids, function, food which contains them, and examples of each ones.
They are insoluble in water and have an oily appearance.
They are classified into:
Fats: high energy giving molecules. There are two types:
o Insaturated (oils): they come from vegetables and
are liquids.
o Saturated: they are got from animals and are solid
at usual temperatures.
Membrane lipids (phospholipids): they form membrane in
cells and organelles.
Regulatory lipids: they are intracellular and extracellular
messengers, such as hormones.
4. Explain what are proteins and aminoacids, and where can we find them on diet.
Proteins are the most important biomolecules in the organism.
They are responsible for making structures and most of the cell
functions.
Proteins are complex molecules made up of aminoacids. There
Human beings can make 12 aa, and the other 8 are necessary
taken on diet. They are called essentials, because without them
our diet is not complete.
The food where proteins are abundant are meats (poultry,
beef, pork…), fish, milk products and eggs.
5. What is the function of minerals? Where can we find them on diet?
Minerals make part of bones and teeth. Their main function
is structural, but they are important in ionic balance too.
The most important source of minerals are vegetables and
fruit.
6. Explain osmosis process.
Activity 1.
7. Why is water important for us?
Water is important for us because most of the body substances
are water soluble, and thanks to the water they can move
“freely” in the cell letting biochemical reactions to take place.
Water is important for delivering substances and transport.
Vitamins are a group of substances with the same function, but
very different from a chemical point of view. Their function is
complete protein structures to let them perform their function.
They are essential for body functions work right. A deficiency
in vitamins always produces an illness (hipovitaminosis). An
excess of them can produce illnesses (hipervitaminosis) but not
always, it depends on the vitamin.
Vitamins are very sensitive to temperature changes, for this
reason many vitamins are destroyed during food cooking. When
food is overcooked is poor on vitamins. For a good input in
vitamins is important to eat raw and fresh food.
9. Explain what are fat-soluble and water-soluble vitamins, their differences and examples of each ones.
Fat soluble vitamins are vitamins which can be solved in organic
substances but not in water. They are vitamins K, A, D and E.
They are stored in the liver. When the body has too much it can
produce an illness for hipervitaminosis, because they are not
easy to be expelled.
Water soluble vitamins can be solved in water. They are group B
(12 vitamins belong to group B) and vitamin C. When there
2) Energy needs
10. Write the amount of energy provided by nutrients.
Carbohydrates: 4 Kcal/g
Fats: 9 Kcal/g
Proteins: 4 Kcal/g
11. What is the basal metabolic rate? What does it depend on?
It is the minimum energy needed by a body to maintain the
vital functions to survive (breathing, blood flow, etc). It is
expressed in Kcal per day, and it depends on sex, age, size
and body mass of the person. In an average person is around
1600 and 1800 Kcal/day.
12. What are structural needs? And functional needs?
Structural needs are the essential substances the body needs
for building and repairing structures in the body. Proteins are
the most important nutrients for this role, but fats have this
function too.
Regulatory and functional needs are the nutrients needed by
the body to perform the metabolic reactions effectively.
Vitamins and minerals are the most important nutrients for it.
3) Diet
13. Describe in your own words, a balanced diet. What are the most usual food and the least?
A balanced diet is a diet compound by different groups of
nutrients in the right proportion between them, namely, 60%
carbohydrates, 30% fats and 10% proteins. It must have a
quantity of minerals and vitamins big enough.
The carbohydrates must be mainly polysaccharides, such as
bread and pasta. Unsaturated fats, as oils, are healthier than
saturated, and the protein source is better if we take fish and
poultry than eggs and red meat because of the cholesterol.
Do not forget drink 2-2’5 liters of water to help your body to
work right and eliminate waste products.
The most usual food must be bread, pasta and vegetables, and
the least abundant must be pastry, sweets and red meats.
14. What are the advantages of Mediterranean diet?
Mediterranean diet is based on vegetables, fruit and fish, and
the main source of fats is olive oil, which is extremely
beneficious in different ways. It is a diet poor in saturated
fats, red meats and sweets, possibly the most harmful groups of
food for our health and circulatory system.
15. What is malnutrition? And poor nutrition? Name some illnesses caused by each one.
Malnutrition is when the amount of food is not enough to satisfy
Types: wasting (caquexia) and kwashiorkor (kwashiorkor), due to
a serious lack of food.
Activities: 26, 27, 28 and 35.
4) Food preservation.
16. Why is food preservation necessary?
Because food is made by organic matter; this is used and
transformed by other microorganisms, changing them and
performing the spoil of it.
17. Make a summary about types of food preservation. Explain uses and examples of each one.
a) Cooling: low temperatures reduce action of enzymes.
a. Refrigeration (few degrees above 0 ºC)
b. Freezing (0 to -18 ºC)
c. Deep freezing (-35 to -150 ºC)
b) Heating: heat destroys enzymes
a. Sterilization: 110ºC. It destroys microorganisms.
b. UHT: 135 ºC for a few seconds
c. Pasteurization: 72 ºC for 15 seconds
c) Drying: eliminates water in food to stop decomposition.
d) Vacuum packing: remove the oxygen and aerobic
microorganisms cannot survive and enzymatic reactions do
not take place.
f) Smoking: substances form burning wood smoke destroys
some microorganisms. Dehydration produced in this process
help to the preservation.
g) Preservatives: large amounts of sugar or salt kill the
microorganisms by osmosis. That happens in salmon, cod,
jam..
Activities 43 and 44.
5) Dietary habits.
18. Make a summary table about problems in diet in developed and developing countries.
Developed countries illnesses
High calorie intake Diabetes
Cholesterol and saturated fats Circulatory problems
Refined food low in fibre Constipation
Much protein rich food Problems in liver and kidneys
Developing countries illnesses
Poor conditions during handling and
preserving food
Infectious diseases and food
poisoning
19. Sum up advantages and disadvantages of genetically modified food.
Advantages Disadvantages
Cheaper food Some components causes
allergies More profitable
Richer in nutrients than the
original
Genetically modified organisms
are stronger than wild
varieties, and that could cause
the extinction of the wild
ones.
