Nucleic acids store, transmit, and help express hereditary information

what are the units of inheritance?

genes

genes

• consist of DNA, which is a nucleic acid made up of monomers called nucleotides.

• program the amino acid sequence of polypeptides.

• amino acid sequence of a polypeptide is therefore determined by a gene.

types pf nucleic acids

1. DNA: (Deoxyribonucleic acid)

2. RNA: (Ribonucleic acid)

DNA

• provides directions for its own replication

• Gene Expression: he process by which DNA directs the synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis.

• Each gene along a DNA molecule directs synthesis of a messenger RNA (mRNA)

• the mRNA molecule interacts with the cell’s protein-synthesizing machinery to direct production of a polypeptide

• The flow of genetic information can be summarized as DNA → RNA → protein

Nucleic acids

• exist as polymers called polynucleotides

• Each polynucleotide or Nucleic acids Consists of monomers called nucleotides

Nucleotide consist of

Ribose sugar + phosphate group + nitrogen base

Nucleoside consist of

ribose sugar + nitrogen base.

how are nucleotides in DNA and RNA linked together?

by a phosphodiester linkage

Pyrimidines

Cytosine , Thymine , Uracil (single six membered ring)

Purine

Adenine , Guanine (six membered ring fused to a five membered ring)

Nucleotide polymers

• linked together by a phosphodiester linkage to build a polynucleotide

• A phosphodiester linkage consists of a phosphate group that links the sugars of

  two nucleotides

• RNA molecules usually exist as single polynucleotides chains

• DNA molecules have two polynucleotides spiraling around imaginary axis, forming

  double helix

• the DNA double helix, the two backbones run in opposite 5→ 3 directions from

  each other, an arrangement referred to as antiparallel

Bioinformatics

uses computer software and other computational tools to deal with the data resulting

from sequencing many genomes

genomics

Analyzing large sets of genes or even comparing whole genomes of different species

proteomics

A similar analysis of large sets of proteins including their sequences

DNA and Proteins as Tape Measures of Evolution

• Sequences of genes and their protein products document the hereditary background of an organism

• Linear sequences of DNA molecules are passed from parents to offspring

• We can extend the concept of “molecular genealogy” to relationships between spec