Basic Science

Types of Carbohydrates: Monosaccharides and Polysaccharides

len Alfred Ajibola - 25th June, 2021 @ 11:15 AM

Topics in Basic Science

Resources from living things Resources from animals Importance of immunization Types of Carbohydrates: Monosaccharides and Polysaccharides Carbohydrates: Disaccharides and Oligosaccharides Len Academy Examination Questions for Basic Science, JSS2, 2nd Term Len Academy Examination Questions for Basic Science, JSS3, 3rd Term Len Academy Examination Questions for Basic Science, JSS3, 2nd Term Primates: Characteristics of Primates Effects of improper waste management Waste Management: Causes of waste in the society Concept of mass and weight Mineral Salts: Sources, functions and deficiencies of macronutrients Sources, functions and deficiencies of micronutrients Len Academy questions for Basic Science JSS1, second Term Len Academy mid-term test questions for Basic Science JSS1, 2nd Term Microorganisms causing food, water and air borne diseases Vector borne organisms and the diseases they cause Bones of the Human Skeleton Meaning of Drugs, Type of Drugs and Side effects of Drugs

Academic Questions in Basic Science

Please click here to see all Questions and Answers

Vaccination involves a process of introducing pathogens or germs into a person in order to prevent such person from the diseases they cause.

  • A. True

  • B. False

With regards to the human health, foreign bodies are best regarded as _____.

  • A. International bodies

  • B. Antilators

  • C. Antibodies

  • D. Antigens

  • E. Antibiotics

  • F. Antidotes

Disease causing organisms are termed _____.

  • A. Pests

  • B. Pathogens

  • C. Vectors

  • D. Insects

  • E. Disease carriers

  • F. All the above options are correct

____ is formed from a reaction utilizing oxygen and glucose in the mitochondria of cells.

  • A. Galactose

  • B. Fructose

  • C. Sucrose

  • D. AMP

  • E. ADP

  • F. ATP

Which of the following statement is false concerning carbohydrates?

  • A. They are composed of carbon, hydrogen and oxygen only

  • B. Carbon has the highest ratio of the constituent elements of carbohydrates

  • C. All carbohydrates are sugars

  • D. Fructose is a carbohydrate

  • E. Natural milk contains lactose and it's a carbohydrate

  • F. Fatty foods contains high calories of energy when compared to the same quantity of carbohydrate foods

Which of the following is a class of food?

  • A. Water

  • B. Fibre

  • C. Roughages

  • D. Latex

  • E. Tanins

  • F. Wax

Brachiation is a specialized form of movement exhibited by _____.

  • A. Human beings

  • B. Babbons

  • C. Chameleons

  • D. Toads

  • E. Millipedes

  • F. Birds

_____ is a form of locomotion whereby an organism move by means of its two hind limbs.

  • A. Pedalism

  • B. Duo Pedalism

  • C. Double Pedalism

  • D. Dual Pedalism

  • E. Bipedalism

  • F. Copedalism

What are Carbohydrates?

Carbohydrates are classes of food composed of carbon, hydrogen and oxygen (CHO) in the ratio of 1:2:1. They are the body's first choice for generating the energy needed to enable us go about our daily activities.

However, fats and proteins can also act as sources of energy but they aren't the body's first choice. As a matter of fact, fatty foods contain a higher calorie of energy (when compared with an equal amount of carbohydrate food). Meanwhile, carbohydrate and protein diets (of equal quantities) are considered to contain similar amount of calories.

Please read on the concept of food here.

Note: Each gram of carbohydrate provides 4 calories of energy. Interestingly, they are the main source of energy for the muscle and brain cells respectively. Understand that other cells outside the brain and muscles can effectively use fats and proteins as alternative sources of energy if the need arises.


Types of carbohydrates?

All carbohydrates are sugars

When we eat rice, yam, table sugar or even glucose, we are essentially eating carbohydrates or sugars. These sugars can be put into four types or classes or categories. They are:

  1. Polysaccharides

  2. Monosaccharides

  3. Disaccharides

  4. Oligosaccharides

Please read on disaccharides and oligosaccharides here.

Below are explanations on polysaccharides and monosaccharides respectively.

  • Polysaccharides

Polysaccharides are complex sugars. They are generally grouped into 4 types. These are:

  1. Starch
  2. Glycogen
  3. Chitin
  4. Cellulose

  • Food containing starch are widely eaten forms of carbohydrates. They include rice, cassava, yam, potatoes, maize, millet and other forms of cereals. Generally, they are the type of polysaccharides we typically eat (in their cooked form) whenever we enjoy a carbohydrate meal.
  • Glycogen is derived from glucose. In simple terms, cooked starch eaten by humans are broken down into glucose which are eventually absorbed into the blood stream and conveyed to the liver. Here, glucose is converted into glycogen (by the joining of many glucose molecules through various glycosidic linkages). The formed glycogen is stored in the liver for a later use when the blood becomes short of glucose at meal intervals.
  • Chitin is a major component of insect and anthropod's skeleton. It functions to protect their internal organs, while also supporting the organisms where they are present.
    Please read more on chitin as a skeletal material here.
  • Cellulose is a major component of a plant's cell wall, (which is often called a cellulose cell wall). Infact, this is what distinguishes a plant cell from an animal cell. Cellulose can't be digested when eaten by humans; hence they function as roughages.
    You can read on the differences between plants and crops here.

Polysaccharides have got a general formula and that's 'Cx(H2O)y'. In this formula, 'x' is always a large number between 200 and 2500. This is however dependent on the repeating monosaccharides.

The image below shows the polysaccharide (starch) formed from many repeating glucose molecules. Glucose is a monosaccharide in this instance.
Starch formed from repeating glucose molecules - Len Academy

You can read on molecular mass and molar mass with their calculations here.

From the general formula above, we can infer that polysaccharides are large molecules composed of repeating units of another type of sugar called monosaccharides or simple sugars.


  • Monosaccharides

Also called simple sugars, they are the end products (or final broken down products) of polysaccharides. They consist of one sugar unit and thus cannot be further broken down.

Consider the narrative below:

  • After we had eaten a starchy food (polysaccharide), various enzymes produced by our bodily cells break down the ingested starch (which is always eaten in its cooked form). The enzymes first digest (breakdown) the starchy food into a double sugar (called disaccharide), then finally into monosaccharides (mainly glucose). This breakdown process of ingested food is termed digestion.

The monosaccharide (glucose) is eventually absorbed into the blood stream (through tiny villi from the small intestine). Eventually, they are conveyed by the blood to various bodily cells where they are utilized for energy production in the mitochondria.

Please read on the basic characteristics of life here.

Understand that glucose is the major monosaccharides utilized in the generation of energy or Adenosine TriPhosphate (ATP) in the cell's power house (mitochondria).

The process of generating ATP in the mitochondria of cells is usually accomplished with the utilization of oxygen; hence the overall process is termed aerobic respiration

Note: Respiration can also occur in the absence of oxygen; and this is termed anaerobic respiration.

Monosaccharides generally have a chemical formula of 'C6H12O6'. This is shown in the image below, with each containing 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms respectively.
Monosaccharides - Glucose, Galactose and Fructose - Len Academy

Glucose, fructose and galactose are the three major types of monosaccharides.

Functionally, fructose is involved in the body's metabolism while galactose has shown to be useful for the normal functioning of erythrocytes or red blood cells.
Please read more on red blood cells and hemoglobin here.

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Amazing facts in Basic Science

Of all animals, mosquitoes hold the record of killing most humans annually. They are responsible for the deaths of 725,000 - 1,000,000 persons yearly

Antibiotics fights and kills bacteria. However, they do nothing to a virus

All insects have six legs. However, dragonfly has six legs but can't walk

The chin is defined as the protruding part of the face below the mouth, formed by the apex of the lower lip. It is shown below:

Chin - Len Academy

Interestingly, humans are the only animals with chin

Cranberries - Len Academy

Ripe cranberries will bounce like a ball. For this reason, they are nicknamed 'bounceberries'. They will also float in water

Tomatoes and Avocados are fruits, not vegetables

Sweat in itself doesn't smell. The smell that accompanies sweat is actually caused by the presence of bacteria on your skin. This bacteria breaks the sweat coming out of your sweat pores down into acids, thus making it smell.

Deodorants contains alcohol and are antibacterial. They work by killing the bacteria that makes sweat smell

Chewing aspirin during a heart attack may be a life saver. This is true because the drug inhibits platelets from forming a clot that can block an artery of the heart, thus stopping a heart attack

The kneecaps of newly born babies are not made of bone. Rather, they are little bits of cartilage which ossifies (turns from cartilages to bone) from age 2 to 6

Ice cubes - Len Academy

Ice cubes made with fresh water are white in color while those made with boiled water are crystal clear


Intelligence Quotient (IQ) is a score derived from a set of standardized tests developed to measure a person's cognitive abilities in relation to their age group.

IQ may also be defined as the ratio of mental age (MA) to chronological age (CA) multiplied by 100.

Below are some formulas pertaining Intelligence Quotient:

  • IQ = MA x 100 ÷ CA

  • MA = Mental age

  • CA = Chronological age

  • IQ above 100 = Brilliance

  • IQ that equals 100 = Average

  • IQ below 100 = Below Average

Human Brain Gyri and Sulci - Len Academy

Among all organisms in the universe, the human brain is the most developed. This highly developed brain present in humans is the biggest factor that makes them unique from every other organism on earth.

According to research, the more folds a brain has, the more intelligent the organism possessing it will become. To this end, humans have brains with the greatest number of folds (or bumps) called gyri and grooves (or indentations) called sulci.

Please read on the uniqueness of man here.

Waste Management can be defined as the process of collecting, processing, recycling and controlling any material considered as waste.

Improperly disposed waste litters on road sides, in land fills, gutters and ditches. They are generally bad for the following reasons:

Wastes can be classified into various types. These are:

  • Biodegradable waste

  • Non-Biodegradable waste

  • Refuse

  • Sewage

  • Recyclable waste

  • Electronic waste

  • Green waste

  • Biomedical waste

  • Metabolic waste

  • Radioactive waste

  • Chemical waste

  • Animal product waste

Please read the explanations on the classification of wastes here

The African Star Apple is a seasonal fruit that grows abundantly in Nigeria and other West African Countries. It's fondly called African Cherry, Agbalumo or Udara in some parts of Nigeria.

African Star Apple, Cherry, Agbalumo, Udara - Len Academy

Below are some benefits of the African Star Apple:

  • It contains high amount of vitamin C

  • It contains a high amount of calcium

  • It contains high amount of potassium

  • It is a powerful antioxidant

  • It aids in weight reduction

  • It contains a high amount of iron

  • Its leaves, fruits and seeds are medicinal

  • It aids digestion and prevents vomiting

Please read more on the african star apple here