The Central Dogma
• States: information
flows in one
direction from DNA
to RNA to proteins.
replication
transcription
• Includes 3 processes:
– Replication
– Transcription
– Translation
• RNA is the link
between DNA and
proteins.
translation
• Single nucleotide
strand
• Sugar: Ribose
• 4 Bases:
–A: Adenine
–G: Guanine
–C: Cytosine
–U: Uracil
• U replaces T
• Three Types of RNA
• mRNA
• Function:
Reads the DNA
(ATCG) and
carries its
message to a
ribosome
• Location: Starts
in nucleus…
moves to
ribosome
Amino acid
Proline
Amino acid
Serine
• tRNA
• Function: Transfers amino acids from the cytoplasm to
the ribosome
• Ribosome will link amino acids together to form a protein
• Location: Cytoplasm
• rRNA
• Function: Used to
build ribosomes
• Location: Cytoplasm
• Ribosome: Makes
proteins
Transcription
• Defined: Process of making mRNA from DNA
– Copying of a gene to eventually make a protein.
• Step 1: RNA Polymerase separates the DNA
nucleotides
• Step 2: Free floating RNA nucleotides match
with the DNA
Reminder: U replaces T
• Step 3: mRNA breaks free in separate pieces
• Step 4: mRNA processing takes place
– Unused portions (introns) are removed and
the used portions (exons) bond together
• Step 5: Final mRNA strand travels to ribosome
• Step 6: DNA recombines to be used again
Transcription Animation
DNA
•
•
•
•
vs.
Double Stranded
Sugar: Deoxyribose
Bases: A T C G
Location: Nucleus
Replication
• Complex enzymes are used
• Base pairing rules guide
replication
• A=T, G=C
• Copies DNA
• Only one copy of DNA is
made
• Location: Nucleus
RNA
•
•
•
•
vs.
Single strand
Sugar: Ribose
Bases: A U C G
Location: Nucleus & Cytoplasm
Transcription
• Complex enzymes are used
• Base pairing rules guide
replication
• A=U, G=C
• Copies a gene
• Many copies and types of
RNA are made
• Location: Nucleus
REview
• Name three different ways that DNA and RNA differ.
• Which RNA:
– is found inside the nucleus?
– transports amino acids to the ribosome?
– exits the nucleus to the ribosome?
– copies the DNA code?
– makes up the structure of ribosomes?
• Perform transcription by using the following
piece of DNA. Introns are underlined. Write the
final strand of mRNA created.
T A C C G T A C A A T G G G A T C