Transcription and Translation:

From DNA to Proteins

How can DNA code for how I look? How does this code give me black

hair & brown eyes? How can this code make me tall or

short?

Recall: Chromosomes, Genes, and DNA

•DNA makes up GENES, which are found on CHROMOSOMES.

•Gene— a segment of DNA that provides information for making a specific protein.

DNA is expressed as PROTEINS—determines your traits!

DNA RNA Proteins (Transcription) (Translation)

THE CENTRAL DOGMA!

Cytoplasm

Nucleus

DNA

RNA

Protein

Replication

Transcription

Translation.

DNA can’t fit through nuclear membrane, so it needs to send a “messenger” RNA (mRNA) to the ribosomes to make proteins.DNA is very important and must be kept protected!

Transcription (DNA mRNA)

Transcription occurs in the NUCLEUS RNA = Ribonucleic Acid (a nucleic acid) DNA is template for RNA mRNA is made of same bases, except uses

URACIL instead of thymine. A pairs with U G pairs with C

Every 3 letters of mRNA are called a CODON.

Transcription

The new mRNA molecule is formed by incorporating nucleotides that are complementary to the template strand.

DNA coding strand

DNA template strand

DNA

5’

3’

5’

3’

G T C A T T C G G

C A G T A A G C C

G

RNA

5’

GG U C A U U C3’

DNA vs. RNA

RNA

1. Single-stranded

2. A pairs with Uracil (U)

3. Sugar = Ribose

4. Location = Nucleus and Ribosomes

DNA

1. Double-stranded

2. A pairs with Thymine (T)

3. Sugar = Deoxyribose

4. Location = Nucleus

There are 3 Types of RNA

mRNA Messenger Job is to

carry the message from the nucleus to the ribosome

tRNA Transfer Job is to

transfer the amino acids to the ribosome

Only in cytoplasm

•rRNA

•Ribosomal

•Composes the ribosome itself

•Only in cytoplasm

Three types of RNA

Translation (mRNA Protein)

Takes place in RIBOSOMES mRNA is template for tRNA Transfer RNA (tRNA)

tRNA translates the message, picks up corresponding amino acid, and puts it together into a protein chain.

Every 3 letters of tRNA are called an ANTICODON.

Translation

DNA mRNA tRNA

DNA ATC CTA GTG CATmRNA UAG GAU CAC GUAtRNA AUC CUA GUG CAU

Amino Acids—make up proteins

"Why do we need mRNA if DNA holds all the genetic instructions for the proteins the cell needs to produce?"

DNA must be protected at all costs AND it is too big to leave the nucleus.

Vocabulary to Know….

DNA Nucleus Ribosomes Transcription Translation RNA Protein mRNA tRNA Amino acid

Quiz yourself!!!!!!