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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
6
Chromosomes
Most human cells contain 46 chromosomes:
2 sex chromosomes (X,Y):XY – in males.XX – in females.
22 pairs of chromosomes named autosomes.
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 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
8
DNA Double Helix
NitrogenousBase (A,T,G or C)
“Rungs of ladder”
“Legs of ladder”
Phosphate &Sugar Backbone
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
Synthesis of hormones Laboratory diagnosis Gene therapy Use in forensic medicine
Uses Of DNA Recombinant Technology
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
DNA fragmentation Cytoplasm and chromatic condensation Membranous bleb formation Phagocytosis of debris
Cont’d
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