QC correction
• Get your folder and be ready to correct your
quick check with a red pen!
Unit 5 – LT 8.10.4b
A nucleotide is the monomer of DNA. It is composed
of three parts: a) a phosphate group, b) a sugar
(deoxyribose), and c) a nitrogen-containing base (A, C,
G or T). More nucleotides make up the DNA.
Unit 5 – LT 8.10.4b
DNA
RNA
Sugar = deoxyribose
Sugar = ribose
Double-stranded
molecule
Single-stranded
molecule
Thymine bonds with
adenine
Uracil instead of thymine
DNA transcription
Unit 5
Genetics
LT 8.10.4a: SWBAT describe and model protein
synthesis
Hook
• http://www.youtube.com/watch?v=yG3Iyb17
KLs
What would you do?
Imagine you are a cook….you
want to make a nice dish. You
take a recipe book out of the
library, you pick up a recipe in
the book. The recipe in the book
is very long, with a lot of
pictures and useless things, and
you don’t want to damage the
book by using it in the kitchen.
IBE- JTPS
• We know that the DNA is our genetic
information and it makes us who we are. How
is the DNA able to do so?
J-TPS (Justify –Think Pair Share)
THINK
PAIR
SHARE
The central dogma
What are the differences
between RNA and DNA?
The central
dogma states that
information flows
in one direction
from DNA to RNA
to proteins.
The central dogma includes three processes.
What is Replication?
– Replication
– Transcription
– Translation
• RNA is a link between
DNA and proteins.
replication
transcription
translation
Transcription converts DNA into RNA
The RNA bases
Adenine
Guanine
Uracil
Cytosine
What base you don’t
find in the DNA
RNA differs from DNA in three major ways:
1. RNA has a ribose sugar instead of a deoxyribose sugar
found in DNA.
2. RNA has uracil instead of thymine.
3. RNA is a single stranded structure
Phosphate
thymine
Phosphate
uracil
ribose
Deoxyribose
OH
DNA
OH
RNA
OH
Transcription is made by RNA polymerase
RNA polymerase is involved in copying the
DNA strand into an RNA strand
start site
transcription complex
nucleotides
Nucleotides pair with one strand of the DNA
RNA polymerase brings and bonds the
nucleotides together.
DNA
RNA
polymerase
moves along
the DNA
The RNA strand detaches from the DNA once the
DNA gene is transcribed
RNA
Check your understanding
RNA polymerase is
•
•
•
•
•
A. an enzyme
B. a gene
C. an allele
D. a type of cell
E. all of above
Check your understanding
The enzyme (protein) RNA polymerase
•
•
•
•
•
A. makes a copy of DNA
B. transfers the DNA into the nucleus
C. copies the DNA in RNA
D. is involved in sexual reproduction
E. makes sure the DNA is copied correctly
• During transcription, RNA polymerase uses one
strand of DNA as a template to assemble
nucleotides into a strand of messenger RNA
(mRNA).
Nucleus
Messenger RNA
Transcription makes three types of RNA
– Messenger RNA (mRNA) carries the message
that will be translated to form a protein.
– Ribosomal RNA (rRNA) forms part of
ribosomes where proteins are made.
– Transfer RNA (tRNA) brings amino acids from
the cytoplasm to a ribosome.
Transcription vs replication
• Is there any difference between transcription
and replication?
The transcription process is similar to
replication.
• The two processes have different end
results:
– Replication copies all the DNA (to make
two strands of DNA)
– Transcription copies only a gene or small
portion of a strand of DNA.
DNA replication
RNA Transcription
(mRNA)
Check your understanding
Transcription is
• A. a process by which a cell makes proteins
• B. a control mechanism to make sure every cell
has the right content of organelles
• C. a process by which the cell copies the DNA into
RNA
• D. a process by which the cell copies DNA into
another strand of DNA
• E. none of above