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DNA and its Processes
Chapter 12 Material on Midterm
The Scientists of DNA
Griffith Avery–MacLeod–McCarty Hershey and Chase Chargaff Franklin Watson and Crock
Griffith
EXPERIMENT Injected mice with
smooth and rough strains of bacteria
CONCLUSION Something is
occurring that changes the bacteria
Didn’t understand process but called it transformation
Avery–MacLeod–McCarty
EXPERIMENT Wanted to
determine what the transforming agent was
CONCLUSION Material that
caused transformation with deoxyribonucleic acid (DNA)
Hershey/Chase
EXPERIMENT Wanted to
determine what material viruses inserted into hosts
CONCLUSION (Genetic) material
of viruses was nucleic acid
Chargaff
NO EXPERIMENT Looked at
concentrations of bases in organisms
CONCLUSION [A] = [T] and [G]
= [C]
HAD NO IDEA WHY!
Franklin
EXPERIMENT Used X-ray
diffraction to study image of DNA
CONCLUSION Figured out:
Helical shape Twisted strands
2 strands Bases near middle
Watson and Crick
NO EXPERIMENT Pulled everyone
else’s information together
CONCLUSION Determined the
structure of DNA
PROCESS BOX 12-1
Pick two of the scientists that helped us understand DNA, and describe the conclusion of each scientist
MUST BE 4 LINES!
Components & Structure of DNA
Double-stranded Each nucleotide (monomer) is made up
of three parts Phosphate group Nitrogenous base
4 types Deoxyribose
5-Carbon Sugar
Components & Structure of DNA 4 different nitrogenous bases
Guanine (G) Adenine (A) Cytosine (C) Thymine (T)
A pairs up with T, and
G pairs up with C
Possible Nucleotides in DNA
Deoxyribose + Phosphate Group + Deoxyribose + Phosphate Group + Deoxyribose + Phosphate Group + Deoxyribose + Phosphate Group +
Guanine (G) Adenine (A)Cytosine (C)
Thymine (T)
PROCESS BOX 12-2
If the top half of a strand of DNA is:
TAG ACT TTT GGC ATC
Predict what the bottom strand would be, AND explain how you are certain of your answer
MUST BE 2 LINES!
Components & Structure of DNA Bonding in DNA
MY NOTES:
Components & Structure of DNA
Purines 2 rings Nucleotide
adenine Nucleotide
guanine
Pyridimes 1 ring Nucleotide
thymine Nucleotide
cytosine
Two styles of
nucleotides based on size
1. Ones with
“y” are
pyrimidines
2. Longer
word; less
rings
Chromosomes and DNA Replication
When DNA goes through mitosis, it condenses for easy sorting and separation When its thin, it’s
chromatin Wrapped around histone
proteins like beads on a string
Coils up Coils coil up A chromosome is the
very condensed form of DNA
Chromosomes and DNA Replication
Goal: two identical strands of DNA General steps:
Unzip double-strands Add new base pairs Clean up
Chromosomes and DNA Replication
DNA Replication1. DNA helicase comes in and unzips the
double helix2. RNA primers are added3. DNA polymerase ‘lands’ on primers and
adds new base pairs4. Two identical daughter strands result
Chromosomes and DNA Replication
1. Parent strand
2. DNA helicase separates
3. DNA Polymerase adds
4. DNA ligase cleans up
PROCESS BOX 12-3
Sum up the process of DNA replication. Be sure to use all of the “actors”: DNA helicase, DNA polymerase, DNA ligase, nucleotides, parent strand, and daughter strands
MUST BE 4 LINES!
Components & Structure of RNA
Single-stranded Each nucleotide (monomer) is made up of
three parts Phosphate group Nitrogenous base
4 types 5-carbon sugar
ribose
Components & Structure of RNA 4 different nitrogenous bases
Guanine (G) Adenine (A) Cytosine (C) Uracil (U)
A pairs up with U, and
G pairs up with C
RNA and Protein Synthesis
RNA and Protein Synthesis
PROCESS BOX 12-4
What are two similarities between DNA and RNA? What are two differences between DNA and RNA?
MUST BE 3 LINES!
RNA and Protein Synthesis
Messenger RNA mRNA Carries copies of instructions for the
assembly of amino acids into proteins from DNA to the rest of the cell
Involved in protein synthesis
RNA and Protein Synthesis
• Ribosomal RNA• rRNA• RNA that makes up a major part of the
ribosome• Site of protein synthesis
ALSO involved in protein synthesis
RNA and Protein Synthesis
• Transfer RNA• tRNA• Transfers amino acid to ribosome during
protein synthesis
And STILL involved in protein synthesis
RNA and Protein Synthesis
Transcription Goal: make a strand of mRNA that “pairs
up” with a template strand of DNA Complementary strand
Steps Unzip double helix Add in RNA bases Break away and leave nucleus
RNA and Protein Synthesis
Transcription RNA polymerase does the job of DNA
helicase and DNA polymerase combined Unzips and adds bases, but only to the
TEMPLATE strand (coding strand)
PROCESS BOX 12-5
Sum up the process of transcription. Be sure to use all of the “actors”: RNA polymerase, nucleotides, and template strand
MUST BE 3 LINES!
RNA and Protein Synthesis
Genetic Code
What do you see?
RNA and Protein Synthesis
The “code” in mRNA specifies the type and order of amino acids REWIND: amino acids are the monomers of
_________
The goal of the code is to help BUILD PROTEIN!
RNA and Protein Synthesis
Most important 4 UAA, UAG, UGA
STOP
AUG “START” Also MET
RNA and Protein Synthesis
Translation Goal: Make a polypeptide chain (protein)
from the information stored in mRNA Involves all three types of RNA! Occurs in cytoplasm of cells
Steps Have mRNA go in ribosome Ribosome reads codons tRNA brings in correct amino acids Protein is built
RNA and Protein Synthesis
Translation Ribosome is site of protein synthesis mRNA strand is fed through Ribosome “starts” at the start codon
_______
RNA and Protein Synthesis
Translation tRNA has an anti-
codon region that is complementary to the codon of mRNA
Each tRNA carries the matching amino acid with it
RNA and Protein Synthesis
Translation As codons are read, matching tRNAs are
brought to the ribosome Amino acids are joined via dehydration
synthesis Peptide chain is made
RNA and Protein Synthesis
Translation Process stops when ribosome encounters
UAA UAG UGA} We code
for STOP!
PROCESS BOX 12-6
How are all three different types of RNA used in translation?
MUST BE 3 LINES!
RNA and Protein Synthesis
Practice Take this DNA
strand, and transcribe the TOP strand
RNA and Protein Synthesis
Practice Take your mRNA
transcript, and translate it into a polypeptide chain
