книги / First steps in biotechnology. ╨Я╨╡╤А╨▓╤Л╨╡ ╤И╨░╨│╨╕ ╨▓ ╨▒╨╕╨╛╤В╨╡╤Е╨╜╨╛╨╗╨╛╨│╨╕╨╕

Fig. 6

2. Write the verbs from the box in the gaps to complete the sentences.

1 The nucleus ___________the blueprint of life and the genetic material. 2 A child _____________ half of the genetic material from each of his/her parents.

3 Each strand ____________ a sequence of bases also called nucleotides.

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4 The length of the DNA strand ____________from organism to organism but within individuals of a particular species it is nearly constant.

5 A certain virus ___________only 50 000 (5 x 104) bases constituting the genetic material.

6 The coding sequence (genes) in humans___________ only five per cent of the total DNA.

WHILE READING

3.Read the text and check your answers to exercise 2.

DNA

Since the time Gregor Mendel began studying about inheritance in garden plants some 150 years back, researchers have worked to learn more about the language of life – how characteristics pass from one generation to another.

Researchers began to understand DNA from the 1800s when they stated that all living beings, whether plants, humans, animals, or bacteria, comprised cells that have the same basic components. Living organism are made up of cells, i.e. cells are the basic units of life. For example, each of us is made up of billions of this basic unit. If one closely inspects the structure of the cell, one is likely to find various smaller bodies or organelles like mitochondria that generates the energy required to perform all life processes (‘the powerhouse’), chloroplast (only in green plants and responsible for their coloration), the central core –‘the nucleus, to name a few. The nucleus harbours the blueprint of life and the genetic material – DNA or deoxyribonucleic acid – and is the control centre of any cell. The genetic material or the blueprint is contained in all the cells that make up an organism and is transmitted from one generation to another. A child inherits half of the genetic material from each of his/her parents. The chemical structure of everyone’s DNA is the same. Structurally, DNA is a double helix: two strands of genetic material spiraled around each other. Each strand contains a sequence of bases, also called nucleotides. A base is one of four chemicals: adenine, guanine, cytosine, and thymine. The two strands of DNA are connected at each base. Each base will only bond with one other base, as follows: Adenine (A) will only bond with thymine (T), and guanine (G) will only bond with cytosine (C). If one strand of DNA looks like A-A-C-T-G-A-T-A-G-G-T-C-T-A-,the DNA strand bound to it will look like T-T-G-A-C-T-A-T-C-C-A-G-A-T-C.

Together, the section of DNA would be represented as given in Figure.

T-T-G-A-C-T-A-T-C-C-A-G-A-T-C

A-A-C-T-G-A-T-A-G-G-T-C-T-A-G

Fig.

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The length of the DNA strand varies from organism to organism but within individuals of a particular species it is nearly constant. For example, a certain virus may have only 50 000 (5 x 104) bases constituting the genetic material whereas a human cell contains nearly 3.2 billion (3.2 x 109) bases in each of the cells (except the germ line cells). The amount and sequence in all the cells of an organism is identical. The DNA is for most part of the time present as condensed body called chromosomes (coloured body) except when it is replicating or dividing. A piece of a chromosome that dictates a particular trait, for example, eye and skin colour in humans, is called a gene. In any cell, the DNA can be classified into two categories – the sequence that codes for traits or genes and the sequence that has no apparent function or the non-coding DNA. The coding sequence (genes) in humans constitutes only five per cent of the total DNA and is identical in all humans. The non-coding sequence, which is nearly 95% in humans, varies from one individual to another.

Christopher Lewis. Biotechnology.©

AFTER READING

5.In pairs take turns to describe DNA using the words from exercise 1 and the phrases from the box.

How I would try to help this situation

Difficulty in making friends

Inability to speak to others

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Being unable to play

Repetitive use of language

Obsessed with an object

Repeating same routines

Fig. 7

4. Match the following synonyms from the podcast.

WHILE LISTENING

5. Listen to the podcast again and answer the following questions:

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1 What kind of a fly can help explain a problem with autism? 2 What system allows human brain to process volume signals?

3 What has Wilson’s team discovered during a series of experiments on fruit flies?

4 Why were mice chosen for the further experiments instead of fruit flies?

5 What ability of the brain could be useful in treating a wide range of other brain development problems including autism?

AFTER LISTENING

6.Think back over the podcast and write down some questions you would like to ask your group mates about AUTISM.

Share your questions with other groups.

Ask your partner / group your questions.

DISCUSSION

7.How can we help people with autism? Give your own ideas for help. Rate them and share your ratings with your partner: 10 = this would be perfect; 1 = this wouldn’t work. Change partners and share your ratings again.

AUTISM

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UNIT 3

GENETIC ENGINEERING

In this unit you will …

Listen / watch, read and talk about

genetic engineering

Nikolai Vavilov

GM food

Learn how to …

offer your opinion

agree and disagree

take part in a debate

Activate your knowledge.

Do you believe the science behind genetic engineering is flawed?

What real-life applications of genetic engineering do you know?

Topic GENETIC ENGINEERING

2. Choose the correct definition a or b for each word in bold.

TIP: Use dictionary to help you. http://www.yourdictionary.com/ or diction- ary.reference.com

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