Objective: Understand the Structure of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Do Now:
•Compare and contrast the two molecules below.
•How are they similar? How are they different?
DNA
RNA
Objective: Understand the Structure of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
How are DNA and RNA similar?
How are DNA and RNA different?
Both share three Nitrogen Bases:
Adenine, Guanine, and Cytosine
RNA contains ribose sugar
DNA contains deoxyribose sugar
Both have a Phosphate Group
and Sugar
RNA is a single stranded molecule
DNA is a double stranded molecule
Both are made of nucleotides
DNA has Thymine instead of Uracil
RNA has Uracil instead of Thymine
Objective Understand the Structure of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Structure of RNA
RNA consists of a long chain of nucleotides.
Each nucleotide is made up of a sugar,
phosphate group, and a nitrogenous base.
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.
Objective: Understand the Structure of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
The Structure of RNA
2
Deoxyribose
1
Ribose
Adenine Cytosine
Guanine Thymine
Adenine Cytosine
Guanine Uracil
Both share three
nitrogen bases:
Adenine, Guanine,
and Cytosine
Both have a
phosphate group
and sugar
Objective: Understand the Functions of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Types of RNA
ribosomal RNA
rRNA
Messenger RNA
mRNA
Carry instruction
from nucleus to
ribosomes
Assemble
aminoacids to
make proteins
Transfer RNA
tRNA
Bring
amino acids to
ribosome
Objective: Understand the Functions of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Types of RNA
Name
rRNA
Ribosomal RNA
mRNA
Messenger RNA
tRNA
Transfer RNA
Function
Assemble
aminoacids to
make proteins
Carry instruction
from nucleus to
ribosomes
Bring
amino acids to
ribosome
Objective Understand the Functions of RNA
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Concept Map of RNA
RNA
can be
also called
which functions to
from
also called
to
which functions to
to make up
also called
which functions to
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Concept Map of RNA
RNA
can be
Ribosomal
RNA
Messenger RNA
Transfer
RNA
also called
which functions to
also called
which functions to
also called
mRNA
Carry
instructions
rRNA
Assemble
Amino acids
tRNA
from
to
to make up
DNA
Ribosome
Proteins
which functions to
Bring
amino acids to
ribosome
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Do Now: List 3 things you already learned about RNA
RNA
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Transcription
http://www.bioplek.org/animaties/moleculaire_genetica/transcriptie.html
•
•
•
•
Transcription: part of the nucleotide sequence of DNA into a complementary sequence of
RNA.
– Helicase binds to DNA and separates the DNA strands.
– RNA polymerase then uses one strand of DNA as a template form which nucleotides
are assembled into a strand of RNA.
Each A of the DNA is represented by a U in the RNA, each T by a A, each G by a C, and
each C by a G.
Each group of three bases on the mRNA is called a codon.
The RNA strand is a separate molecule that carries the complete message to form a single
protein.
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
Transcription
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
1. Write down the nitrogen base sequence of the bottom strand of DNA
A–G–T–A–C–T–A–G–T-T–C–T–C–A
2. Write down the nitrogen base sequence of the mRNA
G – U – A – C – U – A – G – U - U –C – U - C
3. How are both sequences similar and different?
Similarities:
Both share the following nitrogen bases: A, C, and G.
Both have the same sequence of nitrogen bases
Differences:
DNA contains Thymine (T) and RNA contains Uracil (U)
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
the information in a sentence
4. The order of the nitrogen bases is like ______________________
Compare that to a sentences like: “Watson and Crick discovered the structure of DNA”
letters in a sentence
5. The bases of DNA are like _____________________________
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
7. What nitrogen bases are present in DNA molecule?
Adenine (A), Cytosine (C), Thymine (T), Guanine (G)
8. What nitrogen bases are present in RNA molecule?
Adenine (A), Cytosine (C), Uracil (U), Guanine (G)
9. How do DNA and RNA nucleotides pairs?
In replication, from DNA to DNA:
__________
Adenine pairs to __________
Thymine
_________pairs
to __________
Cytosine
Guanine
In transcription, from DNA to RNA:
Uracil
_________pairs to __________
Adenine
Cytosine
Guanine
_________pairs to __________
Adenine
_________pairs to __________
Thymine
Guanine
_________pairs to __________
Cytosine
Thymine
Adenine
_________pairs to __________
Cytosine
Guanine
_________pairs to __________
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
10. Complete the chart.
Nitrogen bases
REPLICATION
TRANSCRIPTION
From DNA to DNA
it pairs to…
From DNA to RNA
it pairs to…
Adenine
A–T
A–U
Cytosine
C–G
C–G
Thymine
T–A
T–A
Guanine
G–C
G–C
DNA
DNA
DNA
RNA
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
11. Transcript the top strand of the DNA molecule into mRNA.
mRNA:
AU GAG CAAG C C U U U UAC U GAUAC C GAAAG
_____________________________________________________________________________
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
9. Draw the process of transcription of the bottom strand.
Picture
Enzyme
Helicase
RNA
polymerase
mRNA -- U C C A A U G G C U U A U U U C G C A
U C CAAU G G C U UAU U U G CA
mRNA: __________________________________________________________________________________
Objective: Understand the process of Transcription
Key Words: Transcription, RNA, messenger RNA, ribosomal RNA, transfer RNA
http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a2.html
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf
•Information, Please
•DNA contains the information that a cell needs to carry out all of its
functions. In a way, DNA is like the cell’s encyclopedia. Suppose that
you go to the library to do research for a science project. You find the
information in an encyclopedia. You go to the desk to sign out the
book, but the librarian informs you that this book is for reference only
and may not be taken out.
1. Why do you think the library holds some books for reference only?
2. If you can’t borrow a book, how can you take home the information in it?
3. All of the parts of a cell are controlled by the information in DNA, yet DNA
does not leave the nucleus. How do you think the information in DNA
might get from the nucleus to the rest of the cell?