Protein Synthesis(DNA and RNA)

DNA

Deoxyribonucleic acid Located in the nucleus Double helix

Twisted ladder

DNA

Watson and Crick described the structure of DNA in 1953

The Nobel Prize in Physiology or Medicine 1962 was awarded jointly to Crick, Watson and Wilkins "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material".

Francis Crick James Watson

DNA

DNA Nucleotide Sugar - Deoxyribose Phosphate Base

Adenine – Thymine Guanine – Cytosine Mnemonic devices

A and T spell “AT”

or

All Tigers Can Grow

DNA

Sides of ladder are consisted of sugars and phosphates

Rungs of ladder are consisted of nitrogen bases

DNA

Hydrogen bonds – hold bases together

DNA Replication

One strand of DNA “unzips” and make two strands of DNA by binding with free nucleotides

DNA Replication

RNA

Different types are used to translate instructions from DNA into making proteins

Ribonucleic acid Located in the cytoplasm

RNA

RNA Nucleotide Sugar - Ribose Phosphate Base

Adenine – Uracil Guanine – Cytosine

Mnemonic devices All Unicorns Can Grow

or

All Unibrows Can Grow

U

Complementary Base Pairing

DNA A-T C-G

Examples of DNA replication: A-T-C-G-G-C-A-T-C

A-A-C-T-G-G-G-C-G

RNA A-U C-G

Examples of transcription: A-T-C-A-C-A-G-T-A

C-A-G-G-A-C-T-A-G

RNA

Three types of RNA Messenger RNA (mRNA)

Half of a ladder Ribosomal RNA (rRNA)

Hamburger bun shaped Transfer RNA (tRNA)

Attach to mRNA

mRNA

tRNA

rRNA

Codons

Codon – a sequence of three nucleotide bases that represents the “code” for one amino acid

Amino acid – a building block for proteins

Codons

Start codon - tells cells to begin making amino acids AUG

Stop codon – tell cells to cease amino acid production UAG UGA UAA

Transcription

The first stage in making amino acids

DNA is the blueprint for making amino acids

Transcription occurs in the nucleus

Transcription

DNA unzips and free ribonucleotides bind to the DNA strand

The finished product is a mRNA strand

mRNA leaves the nucleus and enters the cytoplasm

Translation

The second stage in producing amino acids

Translation occurs in the cytoplasm

A ribosome (or rRNA) attaches to a mRNA and scans the mRNA

Translation

One tRNA (or an anticodon) will attach to a codon to produce an amino acid

After an amino acid is formed, the tRNA will detach from the mRNA

Amino acids are held together by peptide bonds

Two or more amino acids form a peptide

Progression of a protein Amino acid – the building blocks of proteins Peptide – two or more amino acids Polypeptide – several amino acids Protein – several polypeptide chains

Codons

There are 20 amino acids in the human body and 64 different ways to express them 9 essential amino acids 11 nonessential and conditional amino acids

Essential amino acids – cannot be made by the body; as a result, they must come from food

Nonessential – our bodies produce an amino acid

CodonsCodon Wheel

CodonsCodon Chart

Mutations

Gene

Gene – A section of DNA that carries the information on how to make one protein

Gene Mutation

Gene mutation – A mutation that changes one gene Also known as a point mutation

Three types of gene mutations 1. Substitution

Missense Silent Nonsense

2. Insertion (frameshift) 3. Deletion (frameshift)

Gene Mutation

Substitution – a mutation that exchanges one base for another

Original

Substitution

Gene Mutation

Missense mutation – a substitution changes the amino acid

Gene Mutation

Silent mutation – a substitution does not change the amino acid

Gene Mutation

Nonsense mutation – a substitution changes the amino acid to a “stop”

Gene Mutation

Insertion involves adding a base

Deletion involves removing a base

Gene Mutation

Frameshift – the reading “frame” changes, altering the amino acid sequence Found in deletion and insertion mutations

Chromosomal Mutation

Chromosomal mutation – The structure or number of chromosomes change Deletion

The removal of genes Translocation

The broken part attach to another chromosome

Inversion The broken part reattach

backwards