1. Cell Biology
Mrs.Sridevi

2. Cell Biology –Today’s Topics
Chromosome
Size
Shape
Components
Genetic Engineering
Basic techniques
Steps Involve

3. Introduction

4. Chromosome -Size Ranges from 0.25 μm (fungi) – 30 μm (Trillium)
Chromosomes in plants larger than in animals
Chromosomes in monocots larger than dicotyledons
Polytene chromosomes (salivary gland cells of dipteran insects)
Lampbrush chromosomes in Oocytes of vertebrates
Largest chromosomes:

5. Chromosome -Shape

6. Diploid Number of Chromosomes
Chromosome -Number
Species
Botanical Name
Diploid Number of Chromosomes
rice
Oryza sativa 24
maize
Zea mays 20
great millet
Sorghum vulgare
peanut, ground nut
Arachis hypogaea 40
soybean
Glycine max
mung bean, green gram
Phaseolus aureus 22
upland cotton
Gossypium hirsutum 52
mango
Mangifera indica
cassava
Manihot utilissima 36
sugarcane
Saccharum officinarum 80

7. Chromosome -Components
Secondary Constriction
Satellite
Primary Constriction

8. Chromosome -Types

9. Polytene Chromosomes Discovery
C.G. Balbiani (1881) in the salivary glands of Drosophila.
Characteristic features
Inter bands, along the length of the chromosome.
Balbiani ring or chromosomal puff.
Other Name
Salivary gland chromosomes, as they occur in the salivary glands.

10. Special Types: Lampbrush Chromosomes
Discovery
Observation by Flemming (1882)
Description by Ruckert (1892)
Occurrence
At the diplotene stage of meiotic prophase in oocytes of Salamandor
In giant nucleus of the unicellular alga Acetabularia.
Structure
Lateral loops of DNA extend as a result of intense RNA synthesis.

11. Genetic Engineering Selection, Isolation and Cutting of desired gene
Integration of desired gene into vector, mostly plasmid DNA of bacterium.
Result: Formation of recombinant DNA or hybrid DNA.
Introduction into the bacterial host

12. Pharmaceutical Industry
GE - Applications
Pharmaceutical Industry
Production of proteins, enzymes, hormones, antibiotics
Agriculture
Formation of pest resistant, disease resistant plants, edible vaccines
Medicine
Correcting inborn genetic defects. e.g., production of human growth hormone
Forensic Science
Determine criminals through DNA finger printing etc.

13. Thank you