La función del АDN

I. Investigate de following information from internet or from your book.

1. What is DNA?

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA). The DNA in each living cell of an individual is like a master blueprint that contains enough information to build an entirely new individual.

2. Which are the structural units of DNA?

A DNA molecule consists of two chains of nucleotides coiled into a double helix.

3. How are these units constituted?

Each Nucleotide consists of 3 elements:

- A sugar called deoxyribose

- A phosphate group

- Four bases

4. Which the function, structure and localization of DNA?

DNA function is to contain inheritable genetic information of the cell, which proteins are synthesized and organisms develop. DNA is found in all cells of the living being, in particular in the core of the aforesaid and a part of the chromosomes.

If the cell is eukaryotic DNA is found in the nucleus, whereas if the cell is prokaryotic genetic material is dispersed in the cytoplasm that case it nucleoid called as shown in the images of the bottom. The DNA is made by joining small units called nucleotides. Nucleotides are formed by binding of a monosaccharide (sugar), a phosphoric acid and a nitogenada base. There are four nucleotide types differently designated depending on the nucleobase to the accompanying: A (adenine), T (atinine), C (cytosine), G (guanine), these are linked to form chains and wound couple on themselves to form a double helix.

5. What is a gene?

A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins.

6. What is a chromosome?

In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

7.How many chromosomes does the human species have?

Humans have 23 pairs of chromosomes, giving each cell a total of 46.This includes 22 pairs of autosomes and one pair of sex chromosomes.

8. How do we determine the sex of human beings?

A chromosome involved in sex determination. A sex chromosome is a type of chromosome that participates in sex determination. Humans and most other mammals have two sex chromosomes, the X and the Y. Females have two X chromosomes in their cells, while males have both X and a Y chromosomes in their cells. Egg cells all contain an X chromosome, while sperm cells contain an X or Y chromosome. This arrangement means that it is the male that determines the sex of the offspring

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