DNA Structure and Organization

DNA Structure

• The primary structure of DNA is a double helix.
• The secondary structure of DNA was determined by James Watson and Francis Crick in 1953.
• The double helix of DNA is stabilized by hydrogen bonds between the nucleotide bases.
• The major and minor groove in DNA are formed due to the spatial relationship between the two strands in the helix, with the major groove being wider than the minor groove.

Chromatin Structure

• Histones play a crucial role in the chromatin network, forming a structure that allows for the compaction of DNA into the nucleus.

DNA Function and Characteristics

• The primary function of DNA is to store genetic information.
• DNA is a polymer of deoxyribonucleotides.
• The alternating sugar-phosphate units form the backbone of each DNA strand.
• DNA is formed of 2 strands (chains) of nucleotides.
• The shape of DNA is often compared to a twisted ladder.
• The concept of DNA is like a twisted staircase.

DNA Melting and Annealing

• The temperature at which one half of the double-stranded DNA is separated into two single strands is called the melting temperature.
• Denaturation and annealing of DNA occur during natural DNA heating and cooling processes.

Human DNA

• The DNA from 23 pairs of human chromosomes (22 autosomes + two sex chromosomes) have a total length of approximately 1.74 meters.

DNA Bonds

• Deoxyribonucleotides in DNA are linked by covalent bonds.