1.1 DNA structure

Deoxyribonucleic acid (DNA)

A macromolecule found in all living cells that is double-stranded and has a double helix structure.

Chromosome

A structure within cells that contains DNA, organizes genetic information, and is composed of DNA and histone proteins.

Prokaryotic Cells DNA

is located within the nucleoid region, characterized by circular DNA and single chromosome.

Eukaryotic Cells DNA

DNA is located in the nucleus, containing multiple chromosomes (46 in somatic cells, organized into 23 pairs).

Chromatin

The decondensed form of chromosomes, consisting of DNA and histone proteins.

DNA structure

Made up of repeating units called nucleotides, each consisting of a 5-carbon sugar, phosphate group, and one of four bases.

Nucleotide

The building block of DNA, containing a 5-carbon sugar (deoxyribose), a phosphate group, and one of four bases: A, C, T, or G.

5’ prime end

The end of a DNA strand that terminates with a phosphate group.

3’ end

The end of a DNA strand that terminates with a sugar, specifically deoxyribose.

Weak bonds that hold complementary bases of DNA together, crucial for DNA replication.

Hydrogen Bonds

Semi-conservative replication

A process of DNA replication where each new double strand contains one original strand and one newly synthesized strand.

Helicase

An enzyme that breaks hydrogen bonds and unwinds the DNA double helix during replication.

DNA polymerase

An enzyme that adds nucleotides in the 5’ to 3’ direction to the original DNA strand during replication.

Sister chromatids

Identical halves of a duplicated chromosome, formed during DNA replication.

Cell division

The process where DNA replication occurs, ensuring each daughter cell has identical genetic information.