Download Protein Synthesis

3.3.3 Protein Synthesis
Drill
• What are three similarities and three
differences between RNA and DNA?
• What is DNA replication?
Which is which?
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DNA
RNA
DNA vs. RNA
DNA
RNA
Deoxyribonucleic acid
Ribonucleic acid
Double-stranded; double helix
Single-stranded
Nucleotide bases: A T G C
Nucleotide bases: A U G C
Only in nucleus of eukaryotes (in
cytoplasm of prokaryotes)
In cytoplasm
Stores genetic information
Translated into amino acids which
are then assembled into proteins
Organic molecules
Nucleic acids
Nucleotides are building blocks
Made up of sugar, phosphate, and nitrogen bases
DNA Replication
• DNA makes a copy of itself
• Original strand of DNA is “unzipped” by
enzymes
• Following the base pair rules for DNA (A
 T, T  A, G  C, and C  G), each
exposed strand is used as a template for a
new complementary strand
• Occurs in the nucleus
Objectives
• Define gene.
• Differentiate between the three types of
RNA.
• Explain how the sequence of nitrogen
bases in DNA direct protein formation.
• State that proteins determine traits.
Key Questions
• What is a gene?
• What are the roles of each molecule in protein
formation?
• Sequence of nitrogen bases in DNA
• Three types of RNA
• Enzymes
• Amino acids
• Ribosomes
• What macromolecule determines traits?
Vocabulary
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Codon
Gene
mRNA
tRNA
rRNA
Replication
Transcription
Translation
Definition of Gene
• A gene is a segment of DNA that codes
for a protein or RNA
• Albinism occurs when an organism
produces little to no melanin (pigment)
in the eyes, skin, and/or hair
• There are at least 6 different genes
involved in pigmentation (chromosome 9,
10, 11, 13, and 15)
Albino Reptiles and Amphibians
Albino Mammals
Parkinson’s Disease- chromosome 4
How are DNA sequences used
to make proteins?
• DNA's instructions are used to make
proteins in a two-step process. First,
enzymes read the information in a DNA
molecule and transcribe it into an
intermediary molecule called messenger
ribonucleic acid, or mRNA.
• Next, the information contained in the mRNA
molecule is translated into the "language" of
amino acids, which are the building blocks of
proteins. This language tells the cell's proteinmaking machinery the precise order in which to
link the amino acids to produce a specific
protein. This is a major task because there are
20 types of amino acids, which can be placed in
many different orders to form a wide variety of
proteins.
Types of RNA
• Messenger RNA (mRNA)- RNA molecules that
carry copies of instruction for making amino
acids from DNA to the rest of the cell
• Ribosomal RNA (rRNA)- make up ribosomes
• Transfer RNA (tRNA)- transfers each amino acid
to the ribosome as it is specified by coded
messages in mRNA
How Proteins are Made
Animation
• http://www.genome.gov/Pages/Educati
on/DNADay/HowProteinsAreMade.html
Transcription
• RNA molecules are produced by copying part
of the nucleotide sequence of DNA (ATGC…)
to a complementary sequence in RNA
• During transcription, RNA polymerase (an
enzyme) binds to DNA and separates the
DNA strands. RNA polymerase then uses one
strand of DNA as a template from which
nucleotides are assembled into a strand of
RNA.
Base Pair Rules for Transcription
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AU
TA
GC
CG
• THERE IS NO THYMINE (T) IN RNA
Location of RNA
• RNA is formed in the nucleus
• It leaves the nucleus and goes into the
cytoplasm
Transcribe this strand of DNA
GTCAATTTCGGCATA
CAGUUAAAGCCGUAU
Codons
• Codons are groups of three consecutive
RNA nucleotides that specify an amino
acid
• Ex: U G C
Codon Chart
Translation
• In translation, the cell uses information
from mRNA to produce proteins.
• The codons from transcribed RNA are
decoded and used to make amino acids.
These amino acids are then used to
make proteins.
Translate this strand of RNA
CAG
UUA
AAG
CCG
UAU
Glutamine
Leucine
Lysine
Proline
Tyrosine
Why are the nucleotides of RNA separated
into these sections?
Ribosomes Make Proteins
• The ribosomes assemble these amino
acids into proteins.
• Most genes contain nothing
more than instructions for
assembling proteins.
Proteins are the keys to
almost anything that
living cells do.
Other Activities
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Protein Synthesis Power Point with Notes
Billy Madison Activity
Bird Abuse Crime Lab Activity
DNA and Messenger RNA BCR
Crossword Puzzle
Deciphering Duck DNA
DNA to Amino Acid Notes
Protein Synthesis Quiz
Homework
• Protein Synthesis Review Questions
Closure
• List and explain the steps of protein
synthesis.
HSA Practice
• Hemoglobin is an important protein in red blood
cells. The DNA code for hemoglobin contains the
following segment:
TGC-GGA-CTC-CTC
Which of these is the messenger RNA code for this
segment of DNA?
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A
B
C
D
ACG-CCT-GAA-GAA
TCC-GGT-CTC-CTC
ACG-CCU-GAG-GAG
UGC-GGA-CUC-CUC
• This diagram shows the key steps for making
proteins. In which step is messenger RNA
being constructed?
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A
B
C
D
I
II
III
IV
This diagram shows the
key steps for making
proteins. Which step
involves transfer RNA?
A
B
C
D
I
II
III
IV
• How many nucleotides are needed to
code for one amino acid?
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1
3
4
6
• Which RNA sequence is produced using
the DNA sequence AGC-TAC-ACT?
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A
B
C
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UCG-AUG-UGA
UCG-UAC-ACU
TCG-ATG-TGA
AGC-UAC-ACU