What does DNA do?

Make Proteins!

Proteins are important organic moleculesSee. p. 186Why are proteins so important?

Proteins…

are complex moleculesare made of lots of smaller units called amino acids

are made in the cell by cell organelles called ribosomesevery protein is made of a specific sequence of amino acids

Amino Acids

amino acids are the small units that proteins are made ofthere are 20 amino acidsamino acids are found n the cytoplasm and nucleus of cells

Amino acids and DNA

DNA is a complex molecule consisting of nucelotidesthe nucleotides contain bases, sugars and phosphates

bases are the “rungs”the sugars and phosphates are the sides

a codon is a set of three bases that will produce a particular amino acid

Where do genes fit in?

A gene is a section of DNA that gives the instructions to make a specific protein (such as enzymes, hormones, haemoglobin, etc.)

A gene is therefore the set of codons designed to make a sequence of amino acids (which is a protein)

So….

DNA is therefore responsible for the making of proteins!How does this happen???

Transcription

in the nucleus of a cell, a section of the DNA (a gene!) unwinds a bit at a timeextra DNA components are “fed into” the unwound bit, creating a single, complementary strand called mRNAin mRNA T’s are replaced with U’sthis mRNA is the template or instructions for the cell to make a specific protein

Translation

the mRNA works its way out of the nucleus into the cellcool little protein making “devices” called ribosomes attach to the mRNA and use it to link up amino acids in the particular order as specified by the basesthis creates a protein molecule

The End!