Download Replication vs. Transcription vs. Translation

11.2 HW Check
DNA controls cells by encoding the instructions for making
Proteins
_______________________.
How is RNA similar to DNA?
They are both nucleic acids
How is RNA different from DNA? (Hint: 3 ways)
1. Their structures are different- RNA is single stranded (DNA is double
stranded),
2. The sugar in RNA is ribose (DNA’s sugar is deoxyribose),
3. RNA contains different nitrogenous bases- AGCU (DNA contains
AGCT)
What is the role of RNA in the cell?
It forms a copy of DNA that can exit the nucleus and be used to make
protein.
What are the three types of RNA that build proteins? What does each of
them do?
mRNA- brings instructions from DNA in the nucleus to the
cytoplasm
rRNA- makes up the ribosome (an organelle that builds proteins)
tRNA- delivers amino acids to the ribosome to be assembled into a
protein
What is the main difference between transcription and DNA replication?
DNA replication is the process of doubling one’s DNA
(it produces more DNA). Transcription is the process
of converting DNA to RNA (it produces RNA).
What is RNA processing?
The process of changing the structure of the
mRNA so that it can leave the nucleus.
How is the genetic code read?
The genetic code is contained in the sequence of
nucleotides in DNA. Nucleotides are “read” in sets of three.
(Codons)
Where does transcription take place? Where does translation take
place?
Transcription takes place in the nucleus;
translation takes place in the cytoplasm (at the
ribosome)
For proteins to be built (during the process of translation), the 20
different ___amino acids___________ dissolved in the
______cytoplasm_________ must be brought to the ___ribosome___.
Describe how the process of translation works.
The mRNA molecule attaches itself to a ribosome. Each codon on the
mRNA chain codes for a different tRNA molecule, which carries a
specific amino acid. Depending on the sequence of nucleotides in the
mRNA molecule, a tRNA molecule will attach itself to the mRNA within
the ribosome. The tRNA will leave its amino acid attached to the
ribosome, and as the ribosome moves down the mRNA strand, a new
amino acid will be brought to the chain depending on the sequence of
nitrogenous bases on the mRNA strand.
Protein Synthesis
AKA: Gene Expression
NOT A PART OF
PROTEIN SYNTHESIS
Replication:
NOT A PART OF
PROTEIN SYNTHESIS
The process by which DNA makes copies of itself.
NOT A PART OF
PROTEIN SYNTHESIS
-This takes place in the
nucleus of the cell before
the cell undergoes mitosis
NOT A PART OF
PROTEIN SYNTHESIS
Protein Synthesis:
http://www.youtube.com/watch?v=41_Ne5mS
2ls
DNA is important because it is the blueprint for
building an organism.
-DNA is the blueprint for building proteins which
build organisms.
-A protein is a long train of amino acids linked
together.
-Proteins have a number of important
functions:
-they can provide structure (ligaments,
fingernails, hair)
-help in digestion (stomach enzymes)
-aid in movement (muscles), and much more
-We express our genes by using unique combinations of
nucleotides to synthesize unique combinations of proteins
How does DNA synthesize proteins?
Transcription
1. The DNA is converted into a different form (called
mRNA) in the nucleus
mRNA
Processing
2. The structure of mRNA is changed it can exit the
nucleus
Translation
3. The mRNA is sent to a ribosome, where it is used
as a template to place amino acids in the correct
order
The Central Dogma of Molecular
Biology
DNA
Transcription
mRNA
Translation
Protein
In order for DNA to make protein, it must be first
transcribed into mRNA in the nucleus. The mRNA
is then translated into protein in the cytoplasm.
What is a gene?
• A segment of DNA that contains information
for how to build a particular protein
• A gene is like a recipe that tells a cell how to
make a protein
Why do different species look and
function differently?
• They have different genes!
Why do different species look and
function differently?
• They have different genes!
• Different creatures have different genes, but
all genes are written in the same language of
A’s, G’s, C’s, and T’s.
DNA  mRNA  Protein
-In the nucleus, the sequence
of nucleotides in the DNA is
copied into a corresponding
sequence in the mRNA.
-The sequence of nucleotides
in the mRNA molecule
determine the order of amino
acids that will make up the
protein
DNA vs. RNA
DNA
RNA
deoxyribose
ribose
Nitrogenous
bases used:
AGTC
AGUC
# of Strands:
two
one
Sugar:
Kinds of RNA
1. mRNA
A copy of the DNA that travels from the nucleus to the
cytoplasm
Kinds of RNA
1. mRNA
A copy of the DNA that travels from the nucleus to the
cytoplasm
2. tRNA
Transfers amino acids from the cytoplasm to the
ribosome
Kinds of RNA
1. mRNA
A copy of the DNA that travels from the nucleus to the
cytoplasm
2. tRNA
Transfers amino acids from the cytoplasm to the
ribosome
3. rRNA
What the ribosome is made of.
Essential Questions
• What is a gene?
• How are living things related?
• What is the difference between DNA and
RNA?
• What are the three types of RNA used during
protein synthesis?
Transcription
The process of converting DNA to RNA in the nucleus
http://www.youtube.com/watch?v=ztPkv7wc3yU
Transcription
The process of converting DNA to RNA in the nucleus
Transcription: Steps
1. Transcription factors (enzymes) bind to the
promoter region on the DNA strand
2. RNA Polymerase (enzyme) binds to the
transcription factors and begins creating an
mRNA strand that is complementary to the
gene on the DNA
3. The mRNA breaks off from the DNA
Transcription
The process of converting DNA to RNA in the nucleus
Processing the mRNA Transcript
In eukaryotic cells, the structure of the newly-formed mRNA
transcript must be changed before it can leave the nucleus.
A cap is added to one end
A poly-A tail is added to the
other end.
Introns are removed.
Sequences in
the mRNA that
do not code for
a protein
Exons: sequences
in the mRNA that
code for proteins
Translation
The process ribosomes use to synthesize amino acid chains
based off of an mRNA template.
http://www.youtube.com/watch?v=zb6r1MMTkc&feature=related
Translation: Steps
1. An mRNA molecule attaches to a ribosome in the
cytoplasm.
2. The ribosome reads the mRNA in sets of three nucleotides
called codons.
-Each codon is unique and binds to a particular tRNA
molecule.
Translation: Steps
1. An mRNA molecule attaches to a ribosome in the
cytoplasm.
2. The ribosome reads the mRNA in sets of three nucleotides
called codons.
-Each codon is unique and binds to a particular tRNA
molecule.
Translation: Steps
3. tRNA molecules bring the amino acids to the ribosome and
connect them in a chain.
4. The sequence of nucleotides on the mRNA strand
determines which amino acid will be added to the amino acid
chain.
The Genetic Code
-Every codon codes for a
specific tRNA molecule
-Every tRNA molecule is
attached to a specific
amino acid
-Codons in the DNA and
mRNA determine the
order of amino acids in
the protein chain
The Genetic Code
-There are 20 amino
acids used by living
things
-There are 64 possible
codon combinations
-Therefore, it is possible
to have multiple codons
that code for the same
amino acid
http://www.youtube.com/watch?v=41_Ne5mS
2ls
PROTEIN SYNTHESIS:
-Review:What is a protein?
-The Genetic Code (the role of codons)
-DNA vs. RNA
-3 types of RNA:
tRNA
mRNA
rRNA
-3 Steps of Protein Synthesis:
1. Transcription
2. mRNA Processing
3. Translation
TO STUDY FOR YOUR QUIZ:
1.
2.
3.
4.
5.
6.
7.
10.2 Notes WS (HW)
Meiosis drawing
Meiosis Notes (ppt)
11.1 Notes WS (HW)
DNA Structure Notes (ppt)
11.2 Notes WS (HW)
Transcription/Translation
Notes (ppt)
DNA Contains Codes
In the nucleus, the sequence of nucleotides in the DNA is
copied into a corresponding sequence in the mRNA.
DNA
STRING:
INDIVIDUAL
STRANDS OPENED:
mRNA MADE OFF
DNA TEMPLATE:
mRNA FREE TO
LEAVE NUCLEUS
CGTGTCGCCGTGCGTGGCGTGGCGTGGCGCGTTTGCGC
GCACAGCGGCACGCACCGCACCGCACCGCGCAAACGCG
CGTGTCGCCGTGCGTGGCGTGGCGTGGCGCGTTTGCGC
GCACAGCGGCACGCACCGCACCGCACCGCGCAAACGCG
CGTGTCGCCGTGCGTGGCGTGGCGTGGCGCGTTTGCGC
GCACAGCGGCACGCACCGCACCGCACCGCGCAAACGCG
GCACAGCGGCACGCACCGCACCGCACCGCGCAAACGCG
GCACAGCGGCACGCACCGCACCGCACCGCGCAAACGCG