Transcript Transcription & Translation

Transcription & Translation
Mr. Holmes
Biology
Questions to be answered about transcription: (Be
sure to leave space after each question)
1. What is transcription?
2. Where does transcription take place?
3. What are the differences between transcription
and replication?
4. What type of RNA is produced in transcription?
5. What is the region where transcription takes
place called?
6. Where does transcription stop?
7. What are the non coding regions on mRNA
called? Coding regions?
Transcription is the process of turning
DNA into mRNA. It functions in the same
way as replication. Transcription occurs in
the nucleus and base pairs in the same way
except for a couple of differences.
1.
2.
3.
4.
The differences in replication and
transcription are:
The presence of RNA
The use of uracil and not thymine
RNA polymerase is the enzyme used and
not DNA polymerase
RNA has the sugar ribose and not
deoxyribose.
The enzyme RNA polyermase makes a copy of
RNA from only ONE of the DNA strands.
The RNA strand is called mRNA and it codes for
the production of proteins.
The location where transcription starts is called
the promoter region.
The noncoding regions of mRNA are called
introns. The coded regions are called
exons. Introns are cut out and the exons are
glued back together so that translation can
take place.
Let’s check out
transcription
animation!!
Questions to be answered about translation: (Be sure
to leave space for the answers)
1. Where does translation take place?
2. What is the product of translation?
3. How many nucleotides are read at a time? What
is this called?
4. What are the types of RNA involved besides
mRNA? What are their functions?
5. What is the start codon and amino acid being
produced to initiate translation?
6. How does translation end?
The mRNA produced from transcription
exits through the nuclear pores and enters
the cytoplasm.
The final product that is produced in
translation is a protein.
What is the monomer of a protein?
In order to make a protein, three
nucleotides have to be “read” or
translated a time. This grouping of
three nucleotides is called a codon.
Each codon codes for an amino acid.
Besides mRNA, the other types of RNA
used in translation are tRNA and rRNA.
rRNA = ribosomal RNA; these RNA
molecules associate with other proteins to
form the ribosomes. Each ribosome can
accept two tRNAs at a time (carrying amino
acids) and one mRNA.
tRNA = transfer RNA; small RNA molecules that
carry a specific amino acid at one end and an
anticodon region that recognizes and binds mRNA
at the other end. The tRNA that binds to that
mRNA codon determines what amino acid is
added to a protein chain.
The Three RNAs (mRNA, tRNA, and rRNA) all
work together to turn the information in DNA into
a beautiful, 3-dimestional protein!!!
• The steps of translation:
• 1. Initiation: mRNA enters the cytoplasm and becomes
associated with ribosomes (rRNA + proteins).
• tRNAs, each carrying a specific amino acid, pair up
with the mRNA codons inside the ribosomes. Base
pairing (A-U, G-C) between mRNA codons and tRNA
anticodons determines the order of amino acids in a
protein.
• 2. Elongation: addition of amino acids one-by-one:
As the ribosome moves along the mRNA, the tRNA
transfers its amino acid to the growing protein chain,
producing the protein - codon by codon!
• 3. Termination: when the ribosomes hits a stop codon UAA, UGA, or UAG - the ribosome falls apart!
Let’s Check out an
animation of
Translation!!!