Topic: Organic compounds that build organisms – carbohydrates, fats, proteins, nucleic acids

Author: Elżbieta Szedzianis

Target group

5th grade student of elementary school.

Core curriculum

I. Organisation and chemism of life. Student:

3. lists the basic groups of chemical compounds found in organisms (proteins, sugars, fats, nucleic acids, water, mineral salts) and gives their functions.

Lesson objectives

Students describe the meaning and occurrence of organic compounds.

The criteria for success

• you will explain what organic compounds are;

• you will show a link between the chemical structure and properties of carbohydrates, proteins, fats and nucleic acids and their biological function.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basis competences in science and technology; 

• digital competence;

• learning to learn;

• social and civic competences.

Methods/forms of work

Outdistance strategy, talk, working with text, educational game.

Individual activity and activity in groups.

Teaching aids

• abstract;

• interactive whiteboard or traditional blackboard;

• tablets/computers;

• table tents;

• coloured cards;

• glue;

• marker pens;

• dice.

Before classes

Students read the abstract and write a note on the functions of organic compounds in the organism and their occurrence.

Lesson plan overview

Introduction

1. The teacher asks the students to assess their preparation for the lesson using table tents. A green card indicates that the student has read and understood the abstract; a yellow card indicates that the student has read the abstract but cannot understand some of the information; a red card indicates that the student has not seen the abstract.

2. The teacher asks the students which issues in the abstract were difficult for them
   and explains their doubts.

3. The teacher specifies the subject of the lesson and the criteria for success.

Realization

1. Students do the interactive exercise on their own: they create a crossword using the information they have remembered from the abstract. The teacher observes the students' work, gives directions and answers questions.

2. Volunteers present their crosswords to the whole class. Students do these crosswords together.

3. The teacher invites the students to play the game and divides them into five groups, ensuring that each group has a student who has assessed his/her preparation with a red card at the beginning of the lesson. The teacher asks the students in the groups to count out one by one to six and remember their numbers. Each group receives a dice and cards with questions (two questions per group):

• Are all the sugars sweet?

• Are the proteins white?

• Do you eat nucleic acids every day?

• Do you need mineral salts during rapid growth?

• Are the plants fatty?

• Is it possible for the nettle to contain starch?

• Does the body need sugar?

• Do nucleic acids contain genes?

• Does your body contain carbohydrates?

• Does cottage cheese contain carbon?

Students, working in groups, prepare answers to the questions. The teacher points out that each answer must be developed and properly justified. After the time set by the teacher, the students start playing. The first group asks its question to the second group. Representative of the first group throws the dice. The number of pips indicates which student in the second group will answer the question. Students from the asking group may award zero to two points for the answer. If the selected student does not know the answer or if the answer is wrong, the question can be taken over by other students (by raising their hands to volunteer to answer) to score points for their group. When the second group answers the question, it will ask its questions to the third group, the third group will ask its question to the fourth group, and so on.

Summary

Students answer questions asked by the teacher:

• Did you enjoy the classes?

• What helped you learn and what hindered you?

Homework for the interested students

Students do interactive exercise no. 1 and interactive exercise no. 2.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Carbohydrates, fats, proteins, nucleic acids

Carbohydrates, commonly known as sugars, are widespread organic chemical compounds that are composed of carbon, hydrogen and oxygen atoms. They include one molecule monosaccharides, disaccharides and sugars composed of long chains of monosaccharide units, which are called polysaccharides. Sugars with small particles are easily soluble in water, those with long particles – don’t dissolve easy. The first ones are sweet, others have no taste. Carbohydrates are for all beings the source of energy, they are also building material and supplementary material. Very significant are monosaccharides, such as glucose and fructose , which provide energy to cells, as well as ribose and deoxyribose – ingredients of nucleic acids. Disaccharides are: sucrose – used for example to sweeten the tea, lactose – sugar found in milk, maltose – present in sprouting cereals, in nectar and pollens. Polysaccharides are composed of few thousands of glucose particles connected with each other. These are: starch, glycogen, cellulose and chitin.

Fats are composed of carbon, oxygen and hydrogen. These compounds are a perfect spare material, which is a reach source of energy for processes that take place in cells. In plants, fats are stored in the form of an oil, mainly in seeds and some fruit. Animal fats have solid form. They are mainly stored in fat tissue, but also in kidneys, liver, heart – internal organs vital for the body. They have protective and supportive functions there. A thick layer of fat tissue protects animals against mechanical injuries. It also protects them from low temperatures, being an ideal heat‑insulating material. Fat derivatives called phospholipids are very important ingredients that build cell membranes of all living organisms.

Proteins are organic compounds which have elements such as carbon, hydrogen, oxygen, nitrogen and sulphur. They are composed of amino acids connected with each other and forming long chains. There are only 20 amino acids in nature, but there are tens of thousands of proteins. Each amino acid appears multiple times in a protein. The sequence of amino acids in a protein chain decides about the great variety of these compounds and about different functions of proteins. Building proteins are the ingredient of all organisms, they appear e.g. in cell membranes. Enzymatic proteins decide about biochemical reactions in organisms. Immunological proteins, also known as antibodies, fight against foreign bodies which penetrate our organisms and can cause infections or allergies. Growth hormone and insulin are examples of regulatory proteins that are responsible for regulating the functioning of our body. There are also proteins that allow us to contract muscles. Transporting proteins transport substances between cells. They can be spare material in plants. Especially rich in proteins are peas, beans, broad beans, soy and lentils. It happens very often that these compounds can be used as energy source. The properties of proteins depend on their complex spatial structure.

Nucleic acids, which appear in all organisms and viruses, are organic compounds which contain genetic information, that is “the recipe for an organism”. Even though the amount of nucleic acids in cells is around 1%, their role in organisms is extremely important. Each representative of a given species has characteristic, one‑of‑a-kind genetic material, which heavily influences how that representative looks, develops and functions.
Nucleic acids particles have the form of chains that consist of thousands repeated variations of four basic units – nucleitides. Their order, just like the order of letters in a sentence, is the content of the “recipe for an organism”. Deoxyribonucleic acid (DNA) is composed of two strings twisted around each other.

• Organic compounds of organisms are proteins, fats, carbohydrates and nucleic acids.

• Glucose is the main source of energy in cells.

• Polysaccharides have building and spare functions.

• Proteins are the basic building elements of cells and they regulate the life processes.

• Fats are the source of energy and spare material for plants and animals.

• DNA carries genetic information.