DNA RNA PROTEIN TRAIT

Transcription & Translation Chapter 10

UNDERSTANDING RNA

Ribonucleic

Acid

Single Stranded

A

B

C

RNA Nucleotides

A. Sugar (ribose)

B. Phosphate Group

C. Nitrogen Bases (ACGU)

Rules for Base Pairing in RNA::

B.     Adenine:Uracil (A = U)

A.     Cytosine:Guanine (C G)

RNA has Uracil (not Thymine)

DNA RNA Protein Trait

1. Transcription

2. Translation

PROTEIN SYNTHESIS

Transcription In the nucleus Makes a copy of DNA

into mRNA (messenger RNA)

Translation Happens in ribosome Ribosomes are in the

cytoplasm and on Rough ER

Uses instructions on mRNA to make protein

Transcription: DNA to mRNA

RNA polymerase binds to DNA.

DNA unwinds and separates.

Complementary RNA nucleotides are added.

Let’s Watch:http://

vcell.ndsu.nodak.edu/animations/transcription/movie.htm

Translation: mRNA to protein Happens in the ribosome

in the cytoplasm

Uses instructions on mRNA to make a protein

mRNA codes for an amino acid and tRNA delivers it

The Triplet Code: Codon Chart

mRNA is read in sets of three nucleotides called CODONS. Example: AAG

Each codon “codes” for an amino acid. Example: Lysine

The codons on mRNA give the order of amino acids to make a protein.

Transfer RNA: tRNA

Codon 3 nucleotides on

mRNA

Anti-codon 3 nucleotides on

tRNA Complementary to

the codon

tRNA has anticodon on one side and amino acid on other

tRNA anticodon binds to codon on mRNA and attaches correct amino acid to the growing polypeptide chain.

Start codon: Met

Translation Begins with

Translation Ends with

Stop codon:UAG, UAA, or UGA

Let’s watch Translation

http://vcell.ndsu.nodak.edu/animations/translation/movie.htm

Ribosome Structure

made of rRNA

2 sub-units

Point Mutation: one nucleotide is changed