From Gene to Protein

What is a gene?

1. A unit of inheritance

2. A favorite article of clothing

3. A small portion of a DNA molecule

that codes for a protein and thus determines a trait

1 and 3

Proteins

• These are essential macromolecule. • Make up about 45% of the human body.• Most of the rest of the body is made of_______?• Builds and repairs body tissue including muscle• Make up enzymes. • Make up molecules in the immune system and

hormones, which regulate bodily functions such as sex drive.

WATER

Proteins are absolutely essential for good health!

• Below are diagrams of the structures of different types of proteins. Their complex structures led many scientists to believe…genes were carried on proteins NOT DNA

More about Proteins

• Proteins coordinate cellular activities—they allow cells to communicate with each other. They control vital functions like the beating of your…

And more…

• Proteins are involved in molecular transport.

• Hemoglobin is the protein in your blood that makes it RED. It carries oxygen from your lungs to all of the cells in your body.

• Oxygen is used for which cellular process?

• What is the purpose of this process?

And more…

• Proteins are made of amino acids.

• There are 20 different amino acids that can be combined together into the thousands of types of proteins found in a human.

• Your body KNOWS which proteins to produce because of the DNA code!

• The code is written in the letters A-T-C-G.

From Gene to Protein• Each gene on a DNA molecule provides the directions

(in code) for making 1 type of protein. • The protein may determine the color of your hair, or if

you can taste PTC!

In the Nucleus!

• The code is copied from the DNA molecule by messenger RNA (mRNA).

• This process is called transcription.

• It takes place in the nucleus of the cell

Messenger RNA

• mRNA is similar to DNA except

A) It is much shorter than DNAB) It is only made of one strand NOT twoC) It has four nitrogen bases

Cytosine matches with GuanineAdenine matches with Uracil

Messenger RNA

• This is how mRNA works.• A section of one strand of a DNA molecule has

the nitrogen bases:

TCGATCCCA• mRNA uses complementary bases to match

the sequence. Because it is RNA the “A” (adenine) matches with “U” (uracil).

AGCUAGGGU

• Transcription

In the Cytoplasm!

• After transcribing a small section of DNA the mRNA leaves the nucleus and enters the cytoplasm.

• There it attaches itself to a ribosome containing ribosomal RNA (rRNA).

Translation

• At the ribosome, the code is read by transfer RNA (tRNA)

• This process is called translation.

• tRNA reads the code and builds a protein from the information.

Translation

• The code is read as a series of three letter “words”.

• Each three-letter word is called a CODON.

• Each codon specifies a different amino acid.

Transcription and Translation

GCA = ALANINE

Reading the Code

All the Proteins put Together make up

YOU!