Download Welcome to Mrs. Gomez-Buckley General Biology Class (Room 615)

RNA and Protein
Synthesis
Chapter 13
Why do we need RNA?
 DNA cannot leave the nucleus
 DNA gets transcribe into Messenger
RNA (mRNA)
 Once edited, mRNA can leave the
nucleus as a single strand
Similarities and
differences between DNA
and RNA
 http://www.usask.ca/education/coursewor
k/mcvittiej/bio30unit1/overheads/1.23.htm
Similarities and differences between DNA and RNA
Conection between DNA
and Protein
 DNA defines the genotype (genetic
makeup)
 Proteins determine the phenotype
(specific trait)
 Each gene codes for one protein
(polypeptide)
http://www.pbs.org/wgbh/nova/body/rnai.ht
ml
DNA to Protein Connection
 Geneticists Beadle and Tatum studied
mutant strain of orange mold
 This strain was missing a necessary
enzyme for mold to grow
 Each mutant strain was defective in a
single gene
 One gene-on enzyme hypothesis
 More accurate – One gene one
polypeptide
http://www.youtube.com/watch?v=vIrrtM47Wio
9:33
Life is orchestrated by
Proteins
Proteins
 Combinations of 20
different amino acids
linked in long chains
 Function is determined
by amino acid
sequence
 Amino acid sequence
is determined by DNA
sequence
 Used for enzymes,
hair, muscles, cell parts
Amino Acids Linked
 Amino Acids Link Together to Form
a Protein (Polypeptide)
Protein Synthesis
 DNA → RNA → Protein (polypeptide)
 This happens in two main steps:
 Transcription
 RNA synthesis
 RNA editing
 Translation
Transcription-translation
animations
 http://www.hhmi.org/biointeractive/dna/ani
mations.html
 http://www.youtube.com/watch?v=YxLdBN
AxqKg&src_vid=T1DVtDaKEo&feature=iv&annotation_id=annotat
ion_561613
 http://www.youtube.com/watch?v=T1DVtDaKEo
 http://www.youtube.com/watch?v=1fiJupfb
Spg
Information is sent from the Nucleus
to ribosome where protein is made
Outline of making Protein
 Directions on DNA
 DNA opens up and messenger RNA (mRNA) copies
message
 mRNA is edited – some parts taken out (introns)
 mRNA goes out of nucleus to ribosome
 mRNA attaches to ribosome
 Transfer RNA (tRNA) picks up an amino acid
 tRNA attaches to mRNA matching complementary base
pairs at opposite end from amino acid
 Amino acid is attached to other amino acids held by the
ribosome to make a chain of protein
 When protein completely built unattached from ribosome
1. A sequence of
nucleotides
In DNA (a gene) is
transcribed to RNA in
the nucleus
2. The RNA travels to the
cytoplasm where it is
translated into the
specific amino acid
sequece of a polypeptid
A codon is a threebase "word" that
codes for one amino
acid.
Several codons form
a "sentence" that
translates into a
polypeptide.
Transcription players
 DNA
 Messenger RNA (mRNA)
 RNA polymerase
Transcription
mRNA editing
Translation players




mRNA
Transfer RNA
Ribosome
Ribosomal RNA
Translation
Transcription-translation
animations
 http://www.hhmi.org/biointeractive/dna/ani
mations.html
 http://www.youtube.com/watch?v=YxLdBN
AxqKg&src_vid=T1DVtDaKEo&feature=iv&annotation_id=annotat
ion_561613
 http://www.youtube.com/watch?v=T1DVtDaKEo
 http://www.youtube.com/watch?v=1fiJupfb
Spg
 Protein making analogy short movie
http://www.pbs.org/wgbh/nova/sciencenow/
3210/02.html
00:54 – 03:20
What are Mutations
 Any change in the nucleotide sequence
of DNA
 Two types of point mutations (involving
only one or a few nucleotides)
Base substitutions
Base deletions or
insertions
Types of mutations
 Bill Nye Genetics greatest discoveries
 http://www.youtube.com/watch?v=vIrrtM4
7Wio
 http://school.discoveryeducation.com/tea
chersguides/pdf/lifescience/ds/greatest_d
iscoveries_nye_genetics.pdf
From DNA to Protein