DNADNA Genetic material Deoxyribose sugar Adenine, Guanine,

Cytosine, and Thymine

Double-stranded Helical form

RNARNA Protein synthesis Ribose sugar Adenine, Guanine,

Cytosine, and Uracil Single-stranded Linear form

First proposed by Francis Crick (1958) He said that the sequence involved in the

expression of hereditary characteristics is:

DNAto

RNA to

Protein

The Central Dogma involves three major players, namely DNA, RNA, and proteins.

It also involves three processes, namely DNA replication, transcription, and translation through protein synthesis.

It forms the basis of storage, transmission, and expression of hereditary information.

DNA Replication

Transcription

TranslationProtein

Synthesis

DNA ReplicationDNA Replication

• It is part of DNA Synthesis.

• It is the process of duplication of new DNA molecule with the same base sequence as the original DNA molecule.

It is SEMICONSERVATIVESEMICONSERVATIVE or the 2 old strands will serve as the template for the formation of 2 new strands.

It is SEMIDISCONTINOUSSEMIDISCONTINOUS or the new strands formed are attached by fragments (Okazaki fragments).

2 old strands

2 new strands

SEMICONSERVATIVESEMICONSERVATIVE

and

SEMIDISCONTINOUSSEMIDISCONTINOUS

5’

Cytosine

Adenine

Guanine

Thymine

5’

3’

3’

5’

5’ TAC CGG AAT GCA ATG CAT ATG 3’ OLD3’ ATG GCC TTA CGT TAC GTA TAC 5’ OLD

5’ TAC CGG AAT GCA ATG CAT ATG 3’ OLD3’ ATG GCC TTA CGT TAC GTA TAC 5’ NEW

5’ TAC CGG AAT GCA ATG CAT ATG 3’ NEW3’ ATG GCC TTA CGT TAC GTA TAC 5’ OLD

DNA Replication

Transcription

TranslationProtein

Synthesis

It is the process by which genetic information from DNA is transferred into RNA. DNA sequence is enzymatically copied by messenger messenger RNA (mRNA) RNA (mRNA) to produce a complementary nucleotide transfer transfer RNA (tRNA) RNA (tRNA) strand.

One significant difference between RNA and DNA sequence is the presence of UracilUracil in RNA instead of the Thymine of DNA.

An mRNA transcribing a DNA

strand

An mRNA transcribing a DNA strand

TAC CGG AAT GCA ATG CAT ATG DNA

AUG GCC UUA CGU UAC GUA UAC mRNA

TAC GAT ACT GGA CCA CAT CAG Old DNAATG CTA TGA CCT GGT GTA GTC New DNA

UAC GAU ACU GGA CCA CAU CAG mRNA

It is the process of translating RNA message (from mRNA) into proteins with the help of transfer RNA (tRNA)transfer RNA (tRNA)..

This uses an mRNA sequence as a template to guide the synthesis of a chain of amino acidsamino acids that forms proteins.

Translation occurs in the cytoplasm where the ribosomes are located.

1. InitiationInitiation - A ribosome attaches to the mRNA and starts to code at the FMet codon (START codon: AUG, GUG or UUG).

2. ElongationElongation - tRNA brings the corresponding amino acid to each codon as the ribosome moves down the mRNA strand.

3. TerminationTermination - Reading of the final mRNA codon (STOP codon: UAA, UAG, UGA), which ends the synthesis of the peptide chain and releases it.

Specifically, the code defines a mapping between tri-nucleotide sequences called codonscodons and amino acids.

Every triplet of nucleotides in a nucleic acid sequence specifies a single amino acid.

AUG GCC UUA CGU UAA GUA UAU mRNAmRNA

UAC CGG AAU GCA AUU CAU AUG tRNAtRNA

Start Arg Asp Ala Ile His Tyr Protein

DNA Replication

Transcription

TranslationProtein

Synthesis

Protein synthesis is the process by which cells build proteins.

ProteinsProteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds.

Act as enzymes that catalyze biochemical reactions and are vital to metabolism

Structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton

Cell signaling, immune responses, cell adhesion, and the cell cycle

Animals' diets, since animals cannot synthesize all the amino acids they need and must obtain essential amino acids from food

Three possible representations of the Three possible representations of the three-dimensional structure of the protein three-dimensional structure of the protein

triose phosphate isomerase (TPI)triose phosphate isomerase (TPI)

A mutationmutation is a permanent change in the DNA sequence of a gene. Mutations in a gene's DNA sequence can alter the amino acid sequence of the protein encoded by the gene.

Most mutations are neutral or harmless. These are called silent mutations. However, when mutations affect the composition of a gene they can cause illness or even death.

Thesunwashotbuttheoldmandidnotgethishat.

The sun was hot but the old man did not get his hat.

This sentence represents a gene. Each letter corresponds to a nucleotide base, and each word represents a codon. What if you shifted the three-letter "reading frame”?

ThesunwashotbuttheoldmandidnotgethisThesunwashotbuttheoldmandidnotgethishathat..

T hes unw ash otb utt heo ldm and idn T hes unw ash otb utt heo ldm and idn otg eth ish at.otg eth ish at.

OrOr

Th esu nwa sho tbu tth eol dma ndi dno Th esu nwa sho tbu tth eol dma ndi dno tge thi sha t.tge thi sha t.

Mutations are usually due to mistakes that are made when cells copy their DNA before dividing and that are not detected by the cell’s repair mechanisms.

Other mutations may be caused by outside mutagenic agents such as ultraviolet rays and other forms of radiation, chemicals, toxins, and drugs.

Mutations that happen in body cells may cause an illness like cancer.

BRCA1 geneBreast cancer cell

Only mutations that happen in germ cells (egg or sperm cells) are passed from parent to offspring.

In this case, the mutation will be in every cell of the offspring.

Down Syndrome