Download DNA Replication, Transcription, Translation Notes (Central Dogma)

DNA Replication, Transcription, Translation Notes (Central Dogma)
I.
Draw the central Dogma
II.
DNA Replication
A.
Steps
1. DNA _____________ (enzyme) attaches to _________ molecule.
2. Single Strand Binding Proteins (________) Keep the strand __________.
3. __________ moves along DNA breaking hydrogen bonds- “___________” DNA into _________
strands.
4. Each strand now has _____________ ________________ _____________.
5. ____________: Puts down a small RNA primer which is necessary for DNA polymerase to bind
to at the origin.
6. Free floating ____________ in the nucleus form _______________ bonds with unpaired
nitrogen bases.
7. DNA _________ bonds together ______________
8. Topoisomerase: Rotates the DNA to decrease torque (which would shred the helix)
9.
Ligase (enzyme) __________ DNA
a)
Final result = ____ exact copies of DNA
each copy =
B.
Replication occurs at ______________ sites along DNA
If unzipped old segment
= C-C-A-T-G-A-G-T
What will the new segment be?
C.
Leading and Lagging Strand
1. _______ are added to the _____end of the DNA strand
a) DNA replication can only occur in the ______ direction
2. DNA is "______________": Both strands have opposite 5' to 3' orientations (one is "upsidedown" compared to the other)
3. ___________ strand made _______________
4. The other strand ("________________") made in smaller, discontinuous fragments
a) Okazaki fragments"
D.
Telomeres
1. Each round of replication ___________ the 5' end of the lagging strand (by about ______________)
2. If this continued indefinitely, ___________ would get _____________ and shorter after each
_________________.
a) _________________ would start to be lost
3. _______________ at _________ of eukaryotic chromosomes
a) short, ______________ DNA sequence
4. __________________ - enzyme responsible for replicating the ends of eukaryotic chromosomes
a) add more telomere sequence during replication
III.
RNA (Ribonucleic Acid) and Transcription
A.
Structure of RNA
RNA
DNA
# of Strands
Type of Sugar
Nucleotide base pairs
B.
3 types of RNA
*All made in the __________ and travel to the ___________
1. Messenger RNA (___________)
a) ________ straight strand
b) __________ DNA information
c) Serves as ______________ (pattern) for making proteins
2. Transfer RNA (tRNA)
a) Single folded strand
b) _____________ bases pair up
c) Also involved in __________ synthesis
3. ____________ RNA (rRNA)
C.
a)
Globular form
b)
Part of ____________ structure
Transcription – process of making ___________ from ____________
1. ____________ enzyme called ________________ binds to DNA.
2. RNA polymerase separates portion of DNA into two separate strands.
3. Free floating ______________ in nucleus match their nitrogen bases with bases of “unzipped”
DNA.
DNA base code
= C-G-A-T-A
Complimentary RNA =
4. RNA polymerase forms bonds (___________) between _____________ bases.
5. Polymerase connects nucleotides by bonding __________ to _________
6. Enzyme releases new RNA strand when it reaches “______________” on DNA.
D.
Processing mRNA
1. modified nucleotide is added to the 5' end of the transcript.
2. A tail of several hundred ____________ residues is put on the 3' end of the transcript.
3. These modifications function in __________________ and _______________ of the mRNA
4. Exons and Introns
a) Eukaryotic genes contain large stretches of _________________ ("introns")
interspersed between ___________ ("exons")
b) To produce a functional _______________, the __________ must be removed
c) the exons must be spliced together by a _______________
5. Why Introns?
a) Not really answered.
b) Evolutionary baggage? Selfish genes?
c) We do know that having multiple exons in a gene allows eukaryotes to make multiple
functional proteins from one gene ("alternative splicing")
IV.
TRANSLATION - Protein Synthesis
A.
B.
Proteins
1.
Many _____________ linked by ___________ bonds
2.
100’s to 1000’s of AA’s per protein
3.
20 different AA’s
4.
Sequence of AA’s determine structure and function of each protein
Codon – a group of ____ sequential bases of an ______
1.
______ different codons
2.
mRNA
ucuuagcuagcg
-How many codons? _________
3.
C.
Each codon codes for:
a)
1 of the 20 amino acids
b)
_____ or ______ codons
Anticodon
1.
3 base sequence at the _______ of __________
a)
Matches the _______ on _______ strand
D. Translation – putting ____________ (AA’s) together to build __________ from information in ______
1. mRNA and tRNA transcribed from DNA in nucleus.
2. This RNA exits the ________ through pores.
3. _________ travels to _____________.
4. Free floating ___________ are brought to __________ by _______.
5. Protein always starts with ____________ (aug) AA
6. A second AA on tRNA enters ribosome. Codon and anticodon pair up and peptide bonds form
between AA’s.
7. When a _____________ (UAG, UAA, or UGA) is encountered, a release factor binds to the A-site.
8. The ________________________ is released.
9. The ribosome disassembles.
E.
Translation in prokaryotes
1. Since prokaryotes do not have a nucleus, _______________ and ________________ can be
coupled.
2. _______________: simultaneous translation of a transcript (even while transcript is still being
made.
V.
Mutations
A.
Types
1. ______________ mutations: _____ DNA base is replaced by ______ DNA base.
2. __________ mutations: DNA bases are ___________ or ______________
3. Each type of mutation can have ____________ effects, depending on the situation.
B.
Point Mutations
1. Silent - substitution changes a codon to another codon for the same amino acid.
2. Missense - substitution changes a codon to a codon for a different amino acid
3. Nonsense- substitution changes a codon to a stop codon
C.
Frameshift
1. Shift the codons
2. Insertions – ____________ of a nucleotide
3. ____________ – loss of a nucleotide
4. Duplication – ____________ sequences of codons