Topic: Amino acids

Target group

Elementary school student (grades 7. and 8.)

Core curriculum

Elementary school. Chemistry.

X. Chemical substances of biological importance. Pupil:

4) describes the structure and selected physical and chemical properties of amino acids on the example of aminoacetic acid (glycine); writes the equation of the condensation reaction of two molecules of glycine;
5) lists elements whose atoms are part of protein molecules; defines proteins as compounds arising as a result of condensation of amino acids.

General aim of education

The student describes the structure and selected physical and chemical properties of amino acids on the example of aminoacetic acid (glycine)

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• what are amines and amino acids;

• to describe the structure and properties of nitrogen‑containing compounds - on the example of methylamine (amine) and glycine (amino acid);

• to write down the methylamine and glycine formulas;

• to indicate in the formulas of organic compounds a peptide bond.

Methods/techniques

• activating

  • discussion.

• expository

  • talk.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

3. Health and safety – before starting the experiments, students familiarise themselves with the safety data sheets of the substances that will be used during the lesson. The teacher points out the need to be careful when working with them.

Realization

1. Teacher introducing students to the problem of amino acids, refers to the structure of proteins, to their division into acidic, neutral and alkaline. Writes on the board the general formula of amino acids. Presents the illustration of „Amino acids (general formula of amino acids with description)” from abstract.

2. The lecturer explains the principle of creating systematic amino acid names on the example of aminoacetic acid, i.e. glycine. Saves the group pattern on the board and then displays the illustration with the model glycine model.

3. Students watch the film „Examination of the amphoteric nature of glycine”. After issuing the material with the teacher's help, they formulate a research question and write it down in the work sheet. They note the observations and the joint determination of the conclusions.

4. The teacher asks students to do interactive exercises in the abstract.

Summary

1. The student indicated by the teacher sums up the lesson, telling what he has learned and what skills he/she has been practicing.

Homework

1. Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Amino acids

One of the protein breakdown products is ammonia. It means that proteins also contain nitrogen atoms. The basic compounds that build proteins are amino acids – organic compounds containing amine group $\text{– N}{\text{H}}_{\text{2}}$ and a group characteristic for carboxylic acids $\text{– COOH}$.

The amino acid with the simplest structure is glycine.

Another name of glycine is amino‑acetic acid.

Due to the presence of two functional groups: alkaline amine $\text{– N}{\text{H}}_{\text{2}}$ and acidic carboxyl $\text{– COOH}$, molecules of amino acids can be attached via a peptide bond.

The dipeptide may attach another amino acid molecule; the tripeptide will be obtained. The tripeptide may attach further amino acid molecules. In this way, polypeptides are formed, i.e. compounds formed as a result of joining of many amino acid molecules.

• Amines and amino acids are organic compounds containing nitrogen atoms in their molecules.

• The properties of amines change with increasing number of carbon atoms in the molecule.

• Amino acids are organic compounds containing two functional groups: alkaline amino ${\text{– NH}}_{\text{2}}$ and acidic carboxyl $\text{– COOH}$ group.

• Amino acids have the ability to bind using peptide bonds; in this way they form polypeptides.