Topic: Double strand of DNA

Target group

8th‑grade students of elementary school

Core curriculum

General requirements

I. Knowledge of biological diversity and basic biological phenomena and processes. Student:

2. explains biological phenomena and processes occurring in selected organisms and in the environment.

Specific requirements

V. Genetics. Student:

1. presents the structure and role of DNA.

General aim of education

The student acquires knowledge and skills about the topics discussed in the classes

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to describe the DNA structure;

• to describe the relationship between DNA and genes;

• to explain the mechanism of replication of genetic information and when it occurs.

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;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Before classes

• Students get acquainted with the content of the abstract. They prepare to work on the lesson in such a way to be able to summarize the material read in their own words and solve the tasks themselves.

Introduction

• The teacher explains the aim of the lesson and together with students determines the success criteria to be achieved.

• The teacher appoints one student in the class who reminds the class about nucleic acids. The teacher asks students to consider the problem of combining molecules found in DNA..

Realization

• The teacher asks students to read the content of the abstract and to thoroughly analyze the structure of the DNA molecule shown in the picture.

• The teacher announces a movie. He instructs his pupils to write a research question and a hypothesis in the form provided in the abstract. Then he plays the video and the students note their observations and conclusions. The teacher points the person who shares his insights and explains the reasonableness of the conclusions noted.

• The teacher indicates a person who, using a board, a ready‑made model or a self‑made drawing, will discuss the structure of the DNA molecule.

• The students perform Experiment 1, write in notebooks observations and conclusions.

• Students, working individually or in pairs, carry out interactive exercises to check and consolidate knowledge learned during the lesson. Selected people discuss the correct solutions for interactive exercises. The teacher completes or corrects the statements of the proteges.

Summary

• The teacher briefly presents the most important issues discussed in class. He answers the additional questions of the proteges and explains all their doubts. Students complete notes.

• At the end of the lesson the teacher asks: If there was going to be a test on the material we have covered today, what questions do you think would you have to answer? If the students do not manage to name all the most important questions, the teacher may complement their suggestions.

Homework

• Imagine that you have the opportunity to interview an academic - a specialist in the field of today's lesson. What questions would you like to ask him? Write them down.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Double strand of DNA

A molecule of DNA, i.e. deoxyribonucleic acid, is composed of two evenly spaced strands which are spirally twisted around each other, giving the molecule a helix shape. It can be compared to a string ladder where each step is built by a pair of nucleotides. The DNA structure was discovered by James Watson and Francis Crick.

A nucleotide is the smallest building block of DNA. Each nucleotide consists of a deoxyribose sugar group, a phosphate group and a nitrogenous base. Four different nitrogenous bases are found in DNA: adenine (A), cytosine (C) ,guanine (G), thymine (T). Each nucleotide contains only one nitrogenous base, which is why four types of nucleotides are distinguished: adenine, cytosine, guanine and thymine nucleotides. A single strand of DNA consists of a series of nucleotides that are attached to one another through phosphate groups. Nucleotides forming neighbouring DNA strands are bound together by nitrogenous bases. The bases are connected by hydrogen bonds in a strictly defined way: adenine always with thymine and cytosine always with guanine. Thanks to this, the order of the nitrogenous bases in one strand determines the location of corresponding bases in the other strand. This feature of nitrogenous bases is known as complementarity.

• DNA contains genetic material. It is a record of information about the structure and functioning of the body.

• A DNA molecule is composed of nucleotides and has a double‑stranded structure.

• Each DNA nucleotide consists of a deoxyribose sugar, a phosphate group and one of nitrogenous bases: adenine, cytosine, guanine or thymine.

• Nitrogenous bases of the corresponding nucleotides of both strands are bound together by hydrogen bonds in accordance with the principle of complementarity.