GENOMES

2. GENOMES • The entire genetic compliment of an organism. • The complete set of instructions for making an organism • It contains the master blueprint for all cellular structures and activities for the lifetime of the cell or organism

3. GENOMES It is the entire set of hereditary instructions for building, running, and maintaining an organism, and passing life on to the next generation.

4. GENOMES • In a haploid organisms, including bacteria, archaea, virus, and mitochondria, a cell contains only a single set of genome, usually in a single circular or linear DNA (or RNA for some viruses). • the genome of an diploid organism refers to a full set of chromosomes or genes in a gamete.

5. GENOMES • A regular somatic cell contains two full sets of genomes. • Multicellular organisms consists of two distinct parts of genome. i. nuclear genome ii. Mitochondrial genome

6. GENOMES • Each one of earth's species has its own distinctive genome. • Genomes belong to species, but they also belong to individuals. • Unless you are an identical twin, your genome is different from that of every other person on earth. In fact, it is different from that of every other person who has ever lived.

7. GENOMES

8. GENOMES • In most living things, the genome is made of DNA. • The genome contains genes, which are packaged in chromosomes and affect specific characteristics of the organism.

9. GENOMES • In short, the genome is divided into chromosomes, chromosomes contain genes, and genes are made of DNA.

10. CHROMOSOMES • A chromosome is a package containing a chunk of a genome that is, it contains some of an organism's genes. • The important word here is "package": chromosomes help a cell to keep a large amount of genetic information neat, organized, and compact.

11. CHROMOSOMES • Packaging of DNA into chromosomes serves several important functions, i. chromosome is a compact form of the DNA that readily fits inside the cell. ii. Serves to protect the DNA from damage. iii. DNA packaged into the chromosome can be transmitted efficiently to both daughter cells each time a cell divides. iv.Chromosome confers an overall organization to each molecule of DNA

12. CHROMOSOMES • In a few very simple forms of life, such as bacteria, the entire genome is packaged into a single chromosome. But other organisms, with genomes a thousand or even a million times larger than those of bacteria, divide their hereditary material among a number of different chromosomes. Exactly how many chromosomes we are talking about depends on the species.

13. CHROMOSOMES

14. CHROMOSOMES Prokaryotic chromosomes • Bacterial cells contain their chromosome as circular  DNA. • Usually the entire genome is a single circle, but often there are extra circles called plasmids. The DNA is packaged by DNA-binding proteins.

15. CHROMOSOMES • The bacterial DNA is packaged in loops back and forth.  The bundled DNA is called the nucleoid.  • It concentrates the DNA in part of the cell, but it is not separated by a nuclear membrane (as in eukaryotes.) 

16. CHROMOSOMES

17. CHROMOSOME Eukaryotic Chromosome • Eukaryotic cells contain their DNA within the nuclear membrane. • The DNA double helix is bound to proteins called histones.  • The histones have  positively charged (basic) amino acids to bind the negatively charged (acidic) DNA.

18. CHROMOSOME • The DNA is wrapped around the histone core of eight protein subunits, forming the nucleosome.   • The nucleosome is clamped by histone H1.  • About 200 base pairs (bp) of DNA coil around one histone.  • There are five major classes of histones: H1, H2A, H2B, H3 and H4

19. CHROMOSOME

20. CHROMOSOMES