Table of Contents

The Genetic Code

How Cells Make Proteins

Mutations

DNA: The Code of Life

Which picture matches the vocab word?

• Nitrogen bases

• DNA replication

What forms the genetic code?

DNA = sides are made of sugar, “rungs” are made of nitrogen bases, A, T, G, C

What forms the genetic code?DNA STRUCTUREDRAW IN NOTES:

Double Helix shape

nitrogen bases

( (adenine, thymine guanine, cytosine)

Sugar sides

What forms the genetic code?

The order of nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced

What forms the genetic code?

Chromosome

Gene

Gene

Deoxyribose(a sugar)

Phosphate AdenineCytosine

Guanine

Thymine

A gene is a section of DNAGenes are made of many nitrogen bases (hundreds to millions) they code for one protein*Remember: proteins make up everything!

What forms the genetic code?3 nitrogen bases are the code for 1 amino acid

A chain of amino acids make proteins (like a pearl necklace)

Genes are “on” or “off,” make or don’t make a protein

How does DNA copy itself?

DNA replicates, or makes an exact copy of itself

How does DNA copy itself?

Starts with part of the DNA unwinding, nitrogen bases “unzip” and separate

New nitrogen bases match up with the “unzipped” bases

How does DNA copy itself?

A always pairs with T (adenine with thymine)

G always pairs with C (guanine with cytosine)

 

This way, the replicated DNA is always the same as the original DNA

Online assignment

3.2

Which picture best matches the vocab word?

Messenger RNA

Transfer RNA

Where does a cell make proteins?

Start – nucleus

The “code” carried to the cytoplasm

Protein is made in the ribosomes (little dots)/cytoplasm

Ribosome

How does a cell make proteins?

During protein synthesis, the cell uses information on a gene to make a specific protein

Proteins are made of little chains of amino acids

There are 20 kinds of amino acids

How Cells Make Proteins

How does a cell make proteins?

Proteins are made in the cytoplasm with RNA

RNA = similar to DNA but contains A G C U

(adenine, guanine, cytosine, uracil)

A to U

G to C

How does a cell make proteins?

1. mRNA copies the DNA in the nucleus, brings to ribosome in cytoplasm

2. tRNA carries amino acids to the ribosome to make a chain of protein

Protein Synthesis Chart

How Cells Make Proteins

Online animation

http://www.youtube.com/watch?v=erOP76_qLWA&feature=related

3.3

How can mutations affect an organism?

Mutation = any change in DNA or base sequence

Mutations cause an incorrect protein to be made

So, traits may be different from normal!

How can mutations affect an organism?

3 types of mutations:Deletion – base pair is removedAddition – base pair is addedSubstitution – one base pair is switched for another

How can mutations affect an organism?

Mutations can be helpful, harmful, or neither

Brainstorm Examples:

Helpful

Harmful

Neither

How is cancer related to mutations and the cell cycle?

Cancer begins in the cell cycle, when DNA mutation causes the cell to divide uncontrollably

Cancer Cell

Mutations

How is cancer related to mutations and the cell cycle?

Cancer = cells divide uncontrollably

tumor = a mass of abnormal cells

Cancer can spread through the blood stream

Cancer Cell

Mutations

Cancer Cell

Mutations

How is cancer related to mutations and the cell cycle?

Doctors use chemotherapy, surgery, or drugs to treat cancer

Chemotherapy – drugs or radiation to destroy cancerous cells

-can destroy healthy cells too

Mutations video

http://www.youtube.com/watch?v=2ZRYp5kRFfI&feature=related