Carbohydrates, also called carbohydrates, sugars and carbohydrates, are chemical compounds formed by molecules of carbon (C), hydrogen (H) and oxygen (O).
They are essential for the human body, as they have the function of providing energy and assisting in the formation of cells.
Check below 10 exercises on this topic with answers commented by our experts.
question 1
About carbohydrates, it is correct to state
a) are biomolecules found mainly in meat.
b) are classified into two types: major and minor carbohydrates.
c) are classified according to the number of carbons.
d) are essential for the physical reactions of the human body.
e) are considered harmful to human beings.
Correct alternative: c) are classified according to the number of carbons.
Carbohydrates have a ketone functional group, characterizing a ketosis, or aldehyde, which corresponds to an aldose, varying the number of carbons and, therefore, can be classified into:
Monosaccharides: when the number of carbons varies from 3 to 6, for example:
- 3 carbons: triose
- 4 carbons: tetrose
- 5 carbons: pentose
- 6 carbons: hexose
In addition, there are oligosaccharides, which are carbohydrates with 2 to 10 monosaccharide units, and polysaccharides, when there is a chain with more than 10 monosaccharides.
question 2
The general formula for carbohydrates is
a) (CH2O)no
b) (CH3O)no
c) (CH4O)no
d) (CH5O)no
e) (CH6O)no
Correct alternative: a) (CH2O)no.
Carbohydrates are also called carbohydrates, as they are composed of carbon, hydrogen and oxygen.
The general formula is (CH2O)no and the value of n ranges from 3 to 8.
question 3
Regarding the functions of carbohydrates, it is INCORRECT to state
a) Foods containing carbohydrates provide energy to the human body.
b) Starch is a carbohydrate considered the main energy reserve of vegetables.
c) Carbohydrates participate in the formation of nucleic acids, called pentoses.
d) Carbohydrates have a structural function in some cells.
e) Carbohydrates help in the formation of bones in the human body.
Correct alternative: e) Carbohydrates help in the formation of bones in the human body.
The bones that make up the human skeleton are made up of substances such as collagen, potassium, phosphorus and calcium. The latter corresponds to 99% of the substance in the human body.
Carbohydrates are macronutrients found in food and used by the body to provide energy for the body to carry out its activities.
Starch is a type of carbohydrate used as an energy reserve in vegetables. Chitin and cellulose are carbohydrates that play a structural role. Cellulose is present in the cell wall of plants and chitin is found in the exoskeleton of arthropods.
question 4
Glucose and fructose are two types of essential sugars for human consumption that show some differences.
I. Both glucose and fructose are simple carbohydrates (monosaccharides).
II. The union of glucose and fructose molecules generates another type of sugar: sucrose.
III. Glucose is present in fruits, while fructose is present in sweet vegetables.
The correct alternatives are:
a) I, II and III
b) I and II
c) I and III
d) II and III
e) n.d.a
Correct alternative: b) I and II.
Glucose (C6H12O6) is an aldohexose-type monosaccharide, as it has a 6-carbon chain and an aldehyde functional group.
The sources of glucose are: fruits, rice and potatoes.
Fructose (C6H12O6) is a monosaccharide of the ketohexose type, as it has 6 carbons and has the ketone functional group.
The sources of fructose are: fruits, vegetables and cereals.
Sucrose is a disaccharide, formed by the union of glucose and fructose monosaccharides through a glycosidic bond.
The sources of sucrose are: sugarcane and beetroot.
question 5
According to the number of carbons, carbohydrates are classified into _____ types. _____ are simple carbohydrates that are given the suffix -ose. The _____ are complex carbohydrates formed by the union of several _____.
Correctly filling in the gaps is
a) two; monosaccharides; disaccharides; oligosaccharides
b) two; disaccharides; polysaccharides; oligosaccharides
c) three; monosaccharides; polysaccharides; monosaccharides
d) three; polysaccharides; oligosaccharides; disaccharides
it's three; oligosaccharides; disaccharides; monosaccharides
Correct alternative: c) three; monosaccharides; polysaccharides; monosaccharides.
The three types of carbohydrates are: monosaccharides, disaccharides and polysaccharides.
Monosaccharides, also called oses, are the simplest carbohydrates that do not undergo hydrolysis. They have 3 to 6 carbons in their structure.
Disaccharides, which are also called oligosaccharides, are formed by the union of two monosaccharides through a glycosidic bond.
Polysaccharides, on the other hand, are complex carbohydrates with a huge chain formed by the junction of several monosaccharides.
question 6
Polysaccharides are large carbohydrate molecules called complex carbohydrates. They are formed by the union of several monosaccharides through bonds
a) peptides
b) ionic
c) covalents
d) glycosidic
e) metallic
Correct alternative: d) glycosidic.
Glycosidic bonds are covalent bonds formed at the junction of two monosaccharides.
So that the constituents can combine, a water molecule is eliminated with the combination of a hydroxyl linked to a anomeric carbon, that is, the carbon linked to the central oxygen of the cyclic structure, with the hydroxyl of another monosaccharide.
question 7
Disaccharides are water-soluble molecules formed by the union of two monosaccharides. Which of the alternatives below does NOT represent one of this type of simple carbohydrate.
a) sucrose (glucose + fructose)
b) lactose (glucose + galactose)
c) maltose (glucose + glucose)
d) raffinose (glucose + fructose)
e) n.d.a
Correct alternative: d) raffinose (glucose + fructose).
Raffinosis (C18H32O16) is a trisaccharide and not a disaccharide. It is a carbohydrate formed by the union of the monosaccharides galactose, fructose and glucose.
It can be found in foods like beans, broccoli and kale.
question 8
I. Simple carbohydrates are quickly digested when consumed and have a high glycemic level.
II. Complex carbohydrates have a low glycemic level and are present in foods rich in nutrients and fiber
III. For people who want to lose weight, the best carbohydrates are the complex ones because they satiate more.
About simple and complex carbohydrates we can consider the phrases
a) only I
b) II and III
c) only the III
d) I and III
e) I, II and III
Correct alternative: e) I, II and III.
Simple carbohydrates have a simpler chemical structure and are therefore easily digested fast by the body and, therefore, have a high glycemic index, as they enter the current faster blood.
Examples of simple carbohydrates are glucose, fructose and galactose. Foods rich in simple carbohydrates are bananas, rice and white bread.
Complex carbohydrates have a low glycemic index and a long chain of monosaccharides that, consequently, take longer to be absorbed.
The slow digestion of this class of carbohydrates is related to the presence of fiber and other nutrients in the foods that are part, such as whole foods.
Foods with complex carbohydrates are more suitable for those looking to have more satiety and consume rich sources of fiber and vitamins.
question 9
Carbohydrates are the most abundant biomolecules in nature. They are found mainly in vegetables and are considered the main product of photosynthesis. Some examples of carbohydrates are
a) cellulose and chitin
b) iron and magnesium
c) starch and zinc
d) glucose and hydrogen
e) glycogen and boron
Correct alternative: a) cellulose and chitin.
Cellulose and chitin are structural polysaccharides found in abundance in nature.
Cellulose, (C6H10O5)no, the most abundant polymer in nature, is present in the cell wall of plants, being responsible for giving plants rigidity.
The chitin, (C8H13O5N)no, the second most numerous polymer in nature, is present in the exoskeleton of arthropods and in the cell wall of certain fungi, being responsible for protection, in addition to forming structures.
question 10
The food pyramid systematizes foods according to their functions and nutrients. It contains 8 food groups:
- Energy Foods: Group 1
- Regulating Foods: Groups 2 and 3
- Food Builders: Groups 4, 5 and 6
- Extra Energy Foods: Groups 7 and 8
The carbohydrate group is at the base of the pyramid indicating the foods that provide energy for the body. When consumed, carbohydrates are
a) converted to blood sugar.
b) absorbed by the stomach and broken down into enzymes.
c) converted into starch that facilitate peristaltic movements.
d) taken by the blood to the brain acting as neuron trainers.
e) converted into cellulose facilitating the absorption of nutrients.
Correct alternative: a) Converted to blood sugar.
When ingested, carbohydrates go through the digestive system, where enzymes will act to "break" them into smaller, simpler molecules.
After being transformed into assimilable fractions by the body, they are absorbed into the bloodstream, where they will be transported into the cell to participate in cellular metabolism and thus provide the energy that we need.
The main carbohydrate in the blood is glucose, used as a source of energy when distributed throughout the body.
Read more about this topic:
- Carbohydrates: the function and classification of carbohydrates
- Carbohydrates or carbohydrates: what are they?
- monosaccharides
- Disaccharides
- Polysaccharides
Also take the opportunity to test your knowledge withlipid exercises.