III. Make up the questions to the underlined words:

Example: All living things are composed of cells. – What are all living things composed of?

1. Nearly every cell in a person’s body has the same DNA.

2. A small amount of DNA can also be found in the mitochondria.

3. Most scientists say that a phenotype is the set of traits that are physically expressed from the presence of dominant genes.

4. Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA.

5. An important property of DNA is that it can replicate, or make copies of itself.

6. Each chromosome is made up of DNA tightly coiled many times around proteins called histones.

7. Human beings have approximately about 25,000 genes.

8. Cystic fibrosis is an autosomal recessive genetic disorder that affects most critically the lungs, and also the pancreas, liver, and intestine.

9. Recessive traits are those that are expressed only when two copies of an allele are present in the gene.

10. Many personal characteristics, such as height, are determined by more than one gene.

IV. Agree or disagree with the following statements. Give your reasons:

1. The information in DNA is stored as a code which is made up of six chemical bases.

2. DNA molecules carry the genetic code that determines the characteristics of a living thing.

3. Genes are individual segments of DNA that contain the instructions needed to direct the synthesis of a protein with a specific function.

4. Mitochondria do not have a small amount of their own DNA.

5. Chromosomes are visible even when the cell is not dividing.

6. A phenotype is influenced by a combination of genetic and environmental factors.

7. Genotype and phenotype are very similar-sounding words that are related, but actually mean different things.

8. When both parents have blue eyes they will both have a pair of recessive genes for blue eye color. All of the children will therefore have blue eyes.

9. Biological sex is determined by the presence or absence of a Y chromosome.

V. Translate the following text into English using the words from the text:

Успадковані ознаки закладені в матеріальних одиницях, генах, які розташовуються в хромосомах клітинного ядра. Наприкінці XIX століття в роботах Грегора Менделя були сформульовані основні закони, що визначили спадкову передачу ознак з покоління в покоління. На початку ХХ століття в дослідах Т. Моргана було доведено, що елементарні успадковані ознаки обумовлені матеріальними одиницями (генами), локалізованими в хромосомах, де вони розташовуються послідовно один за одним.

VI. Retell text a using the questions after it as a plan.

VII. Read the text using a dictionary and speak on it:

Variations in our genetic code

All humans have the same set of genes, and the sequence of our base pairs is remarkably similar. However, this doesn't mean that we all have exactly the same nucleotide sequence in our genome.

The passage of the genetic code from generation to generation via the sperm and ova of our ancestors requires replication of DNA, and while replication is remarkably precise, errors occasionally occur and produce changes in the base sequence. It is these changes that produce the variation that makes each of us genetically unique (except for identical twins), and they also drive evolution of species.

There may be a variation in the sequence of letters in the message, a deletion or insertion of individual letters into the code or the deletion or insertion of one or more whole words within the message. Even a deletion of the whole gene can occur.

Variations in the code can occur during our life for a variety of reasons including exposure to radiation or certain chemicals. However, ageing is one of the most common causes of genetic variation. Our cells need to be continually replaced: the cells (and their genetic make-up) are copied over and over again as time goes by. Sometimes mistakes occur in this copying process, and variations in the genes build up in our cells.