Transcript RNA and Protein

DNA,RNA, and Protein
Synthesis
Chapter 12
What is a gene? Where is it
located in a cell?
What is a protein? Where are
they made in cells?
In cells, how do we get from a
gene to a protein?
The Central Dogma:
DNA > RNA > PROTEIN
What is RNA? Compare and
contrast to DNA:
RNA
Ribonucleic acid
Is single stranded
Has uracil
Has a ribose sugar
DNA
deoxyribonucleic acid
is double stranded
has thymine
has a deoxyribose
sugar
What are the 3 types of RNA?
What is the function of each?
mRNA – messenger RNA carries genetic
information from DNA in the nucleus to
direct protein synthesis in the cytoplasm.
tRNA – transfer RNA transports amino
acids to the ribosome
rRNA – ribosomal RNA associates with
proteins to form the ribosomes
Two Stages of Protein Synthesis:
I.
The first Stage is Transcription – the
process in which mRNA is synthesized
from template DNA.
Firefly - http://learn.genetics.utah.edu/content/begin/dna/
RNA Editing:
• Before the mRNA transcript (pre-mRNA)
can leave the nucleus, it must be edited.
The Genetic Code:
• The language of mRNA
TACAGCGTGATT = DNA Sequence
?
mRNA Sequence
?
amino acid sequence
THE GENETIC CODE:
II.
The Second Stage of Protein Synthesis
is Translation:
http://highered.mcgrawhill.com/sites/0072437316/student_view0/chapter15/animations.html#
Animations:
•
Transcription/Translation Animation http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html
•
Firefly - http://learn.genetics.utah.edu/content/begin/dna/
•
Transcribe and Translate Game http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html
•
McGraw-Hill Higher Ed Translation Animation – http://highered.mcgrawhill.com/sites/0072437316/student_view0/chapter15/animations.html#
Mutations:
• Are permanent changes in a cell’s DNA.
• Are mutations good or bad?
Mutations can be good!
- Lead to adaptations which are
important for survival
- And genetic diversity which makes you,
YOU!
Mutations can also be bad:
• Mutations can cause changes in a gene that
cause a protein to be nonfunctional.
• TYPES OF MUTATIONS:
1. Point Mutations are single base
substitutions (one base is exchanged for
another).
a. Missense Mutations (code for wrong aa)
b. Nonsense Mutations (cause termination)
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2. Frameshift Mutations – result from the
insertion or deletion of bases which cause a
shift in the frame of the amino acid sequence.
Insertion – a gain of a nucleotide in the
DNA sequence.
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Deletion – the loss of a nucleotide in the
DNA sequence.
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Duplication:
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THE BIG FAT CAT ATE THE WET RAT
THE BIG FAT CAT ATE THE WET RAT
THE BIG FAT CAT ATE THE WET RAT