YouTube - "The Gene Scene"
What is the difference between RNA and DNA?
The Structure of RNA
• There are three main differences between
RNA and DNA.
1. The sugar in RNA is ribose instead of
deoxyribose
2. RNA is generally single-stranded
3. RNA contains uracil in place of thymine.
DNA Transcription & Translation
• Bio 6B: Explain
replication,
transcription, and
translation using
models of DNA and
ribonucleic acid RNA
Transcription
DNA
Translation
mRNA
occurs in nucleus
Protein
occurs on ribosome
Transcription and Translation in the cell
http://www.youtube.com/watch?v=983lhh20rGY
3 Types of RNA
• There are three main types of RNA: messenger
RNA, ribosomal RNA, and transfer RNA.
DNA Transcription
• The word transcribe means “to copy”. During transcription, the
genetic information code is copied into a single strand of mRNA.
mRNA is known as “messenger” RNA because it carries the DNA
code or message out of the nucleus and into the cytoplasm.
• DNA cannot travel out of the nucleus but RNA can.
• RNA contains the base Uracil instead of Thymine.
Transcription Activity:
Transcribe the DNA strand on your handout into a strand of
mRNA.
REMEMBER: Uracil is in a RNA strand instead of
Thymine.
Example:
DNA: TACACGATT
mRNA: AUGUGCUAA
Translation
• In order for translation to begin, mRNA must first attach
itself to a ribosome which is found in the cytoplasm of a
cell. The information in mRNA is organized into threeletter blocks called codons. Codons are like words of the
RNA message.
Codon Activity
• Organize your mRNA into three letter
blocks called codons.
• Example:
• mRNA: AUGUGCUAAG
•
AUG UGC UAC
Three letter blocks = codons
Codons
• Each codon codes for a
specific amino acid in the
protein chain. tRNA
(transfer) matches a
particular codon to a
particular amino acid.
Amino acids are joined
together in the correct
sequence to form a
protein chain.
How do I read a Codon chart?
•
•
•
•
“First letter” represents the first
letter of a codon. Example: AUG
“Second letter” represents the
second letter of a codon.
Example: AUG
“Third letter” represents the third
letter of a codon. Example:
AUG
The amino acid coded for the
codon AUG is methionine.
It’s your turn to practice using the
codon chart! Identify the amino acids
represented by the codons on your
handout.
Codon chart activity
Use your codon chart to identify the amino
acids coded in your mRNA strand.
LET’S WRAP IT ALL UP! (click below to play clip)