OVERVIEW OF GENETICS & APOPTOSIS

The study of genes and the inheritance of traits

Gregor Mendel’s work determined that hereditary characters are transmitted to offspring by separate units

Later known to be genes

Genetics

Characteristics

These are features you exhibit physically

( your looks)

Example: Eye color - green

Traits

The different versions of a characteristic

Example: blue, green, and brown eyes

Inheritance

Occurs when traits are passed down from parent to child.

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Chromosomes

Most human cells contain 46 chromosomes:

2 sex chromosomes (X,Y):XY – in males.XX – in females.

22 pairs of chromosomes named autosomes.

1

DNA stands for deoxyribose nucleic acid

This chemical substance is present in the nucleusof all cells in all living organisms

DNA controls all the chemical changes which take place in cells

The kind of cell which is formed, (muscle, blood,nerve etc) is controlled by DNA

The kind of organism which is produced (buttercup,giraffe, herring, human etc) is controlled by DNA

DNA 2

DNA is a very large molecule made up of a long chain of sub-units

The sub-units are called nucleotides

Each nucleotide is made up of

a sugar called deoxyribose

a phosphate group -PO4 and

an organic base

DNA molecule3

Ribose is a sugar, like glucose, but with only fivecarbon atoms in its molecule

Deoxyribose is almost the same but lacks one oxygen atom

Both molecules may be represented by the symbol

Ribose & deoxyribose 4

The most common organic bases are

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

The bases 5

The deoxyribose, the phosphate and one of the bases

adenine

deoxyribose

PO4

Combine to form a nucleotide

Nucleotides 6

A molecule of DNA is formed by millions of nucleotides joined together in a long chain

PO4

PO4

PO4

PO4

sugar-phosphate backbone

+ bases

Joined nucleotides 7

In fact, the DNA usually consists of a double strand of nucleotides

The sugar-phosphate chains are on the outsideand the strands are held together by chemical bonds between the bases

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PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

PO4

2-stranded DNA 9

DNA Double Helix

NitrogenousBase (A,T,G or C)

“Rungs of ladder”

“Legs of ladder”

Phosphate &Sugar Backbone

Genes

Bits of information passed down from parent to child.

Made of chemicals called DNA.

How DNA works

National Human Genome Research Institute - NIH

Proteins are long chains of amino acids

The sequence of bases in a gene is a code instructing the cell how to construct a particular protein – i.e. the number of amino acids and the order in which they are to be assembled.

His Met

Phe

His

Glu

Pro

Cys

Cys

M A Glu K

Recombinant DNA technology PCR Botting technique Southern Blotting Western Blotting Northern Blotting

Application Of Genetics In Medicine

Recombinant DNA Technology

Synthesis of hormones Laboratory diagnosis Gene therapy Use in forensic medicine

Uses Of DNA Recombinant Technology

Trisomy 21 Turners syndrome Klinefelters syndrome X-linked disorders

Chromosomal Disorders

Point mutation Frame shift mutation

Mutation

Oncogenes (RET proto-oncogene) Tumor suppressor genes ( p53 , RB gene) Telomerase

Cancers

Apoptosis is also called as programmed cell death

Controlled by cell’s genes Cell suicide Different from necrosis No inflammation Physiological process

Apoptosis

Apoptosis for proper development of tissues Apoptosis for normal functioning of body Apoptosis of cells that are a threat to

integrity of tissues

EX’S OF APOPTOSIS

Internal stimuli External stimuli Final common pathway

Cont’d

DNA fragmentation Cytoplasm and chromatic condensation Membranous bleb formation Phagocytosis of debris

Cont’d