4 Criteria Necessary for being "Genetic Material
1. Information;
2. Replication;
3. Transmission;
4. Variation;
Griffith's Bacterial Transformation Experiment: late 1920s
What are the two strains of Streptococcus pneumoniae?
1. Smooth (S): secretes "capsule" --> fatal in mice;
2. Rough (R): does NOT secrete "capsules" --> NOT fatal in mice;
Why is the Smooth strain fatal in mice?
Capsule shields the bacteria from the immune system of the mouse.
What is the mice are injected with the Heat-Killed S Strain?
Mice survive, b.c. the strain has been killed;
What if we mix live R and dead S, and inject mice with that?
Mice blood is found to have a LIVE S TYPE BACTERIA (when it was injected with the dead). This is TRANSFORMATION.
How is the Transformation possible?
Genetic material has been transferred from the dead S strain onto the live R strain. The capsule-secreting trait has been passed on to the offspring.
Avery, McLeod and McCarty used Purification Methods to reveal that DNA is the genetic material? How did they do it?
1. Start with heated-killed S cells;
2. There are macromolecules in them: DNA, RNA, proteins, lipids, CHs - one of these SHOULD carry the genetic material;
3. Proteins were suspected to be the most possible candidate due to its variability; DNA - not, it'
Phage
Virus that infects bacteria;
Hershey Chase Experiment
Main Idea: DNA not the protein carries the genetic material;
1. Used Virus/Phage to prove that DNA carries the genetic material;
2. Experiment: DNA in the head of virus, surrounded by protein; Put radioactive material on protein coat --> nonradioactive DN
Nucleotides
Building blocks of DNA and RNA;
Strand
A linear polymer strand of DNA or RNA
Double helix
The two strands of DNA
Chromosomes
DNA associated with an array of different proteins into a complex structure;
Genome
The complete complement of genetic material in an organism
DNA
1. Formed from nucleotides: A, T, G, C
Nucleotide Composition
1. Phosphate Group;
2. Pentose Sugar: ribose or deoxyribose;
3. Nitrogenouse Base: Purines and Pyrimidines;
Why us Genetics important?
It explains why dogs have puppies and cats have kittens;
What's a Nucleic Acid?
DNA and it's molecular cousin RNA. They are polymers consisting of nucleotides.
What are nucleotides?
Building blocks of DNA.They are responsible for storage, expression, and transmission of genetics information;
What is the structure of a nucleotide?
A phosphate group; a pentose sugar, and a nitrogenous base.
How do nucleotides in DNA and RNA differ?
They contain different sugars;
DNA - deoxyribose;
RNA - ribose;
I believe in you!
And you believe in you!
What's the same and what differs in nucleotides?
Phosphate group is same;
Rings differ: 2 rings - purines, 1 ring - pyrimidine;
Also, there could be 5 bases: Adenine, Cytosine, Thymine, Guanine, Uracil;
What are purines?
Double ring structure (not the ring of sugar, but the base attached to sugar): Adenine and Guanine (PURINAG)
What are pyrimidines?
Single ring structure attached to a sugar ring: Thymine and Cytosine;
What actually bonds in DNA and how?
Hydrogen bonds occur between purines and pyrimidines;
How many H-Bonds do G-C have?
3
How many bonds do A-T have?
2
What is the RNA's relationship to DNA?
RNA is DNA's precursor;
RNA has catalytic capabilities. What does that mean?
It is able to bring reactants together to form products;
RNA is only one-stranded. So what?
Instability --> damaged easier --> more error-prone;
mRNA, rRNA, tRNA together possess all the functions necessary for an organism to function;
...
So if RNA is easily damaged, why keep it?
It can do more stuff than DNA;
DNA-Gene-Chromosome = not the same thing
Cell Nucleus--> Chromosome --> DNA (part of coil) --> Gene (specific series of nucleic acids);
Genome
All of chromosomes of an organism;
Each species has its own genome;
Exons and Introns
Exons - bits of DNA that codes for a specific gene Introns - bits that do not code for anything;
What part of DNA is like Legos?
Exons; They can be shuffled to make different proteins; We are who we are because of the proteins; :)
What affects DNA in our life?
Interactions between an individual cell and its immediate environment; Example: PTSD
How does the human brain work?
By releasing and binding various neurotransmitters (peptides);
Neurotransmitters = peptides --> coded by specific genes --> activated or repressed by "regulator" proteins --> regulator proteins coded by "specific" genes --> these are activated by other pr
What's the deal with Myriad Genetics?
The company found BRCA1 and BRCA2 genes sequences. Wanted to patent it and charge anyone wanting to use it. LOTS OF MONEY!!! But July 2013 The US Supreme Court ruled unanimously against Myriad. DNA is a"product of nature and is not patent eligible
Transforming Principle
DNA that is transferred from one individual to another in genetic transformation. Many experiments starting in 1920's tried to determine Transforming Principle.
1923 Feulgen
Used Shiff reagent to stain cell.
DNA stained red.
Found that whatever was red to localized to the chromosomes in the nucleus;
1923 Gruffith's streptococcus pneumoniae Experiments
Griffith used two strains of pneumococcus (Streptococcus pneumoniae) bacteria which infect mice - a type III-S (smooth) and type II-R (rough) strain.
Live S Form --> Mouse Dead;
Live R Form --> Mouse Alive;
Heat killed S --> Mouth Alive;
Heat killed S + L
1944 Avery, McLeod, McCarty
Purified the transforming principle;
TP destroyed by DNA degrading enzymes;
But TP untouched by protein and RNA degrading enzymes;
DNA IS THE TRANSFORMING PRINCIPLE!
RNA Composition
1. A, G, C, U;
2. Phosphate Group;
3. Pentose Sugar: Ribose;
4. Nitrogenous Base: Purines (A, G) and Pyrimidines ( C, U)
How are Nucleotides numbered?
1. Sugar Carbons go 1' to 5';
2. Base is on 1';
3. Phosphate is on 5'
How are nucleotides bonded to each other?
Covanlently;
What links the two sugars together?
Phosphodiester Bond; Phosphate group links the two sugars together;
What forms the nucleotide back bone?
Phosphates and Sugars; Bases project away from the backbone;
What is the direction of the strand?
5' to 3'
Ex: 5' - TACG - 3'
Base Pairing
A=T; C=G
Features of DNA
1. Double stranded
2. Antiparallel strands
3. Right-handed helix
4. Sugar-phosphate backbone
5. Bases on the inside
6. Stabilized by H-bonding
7. Specific base-pairing
8. ~10 nts per helical turn
Chargoff's Rule
A pairs with T;
C pairs with G;
This keeps the width consistent;
Complementary DNA strands
5' - GCGGATTT - 3'
3' - CGCCTAAA - 5'
Antiparallel DNA strands - what does this mean?
One strand 5' to 3'
Other stand 3' to 5'
Grooves in DNA molecule. How many and what are they?
2 grooves: major and minor;
Parental vs Daughter Strands
In replication:
Parental = Original;
Daughter = Newly Made;
Semiconservative Mechanism of DNA Replication
1 double blue = 2 blue/red(daughter) doubles
Conservative Mechanism of DNA Replication
1 double blue = 1 double blue + 1 double red (daughter)
Dispersive Mechanism of DNA Replication
1 double blue = 1 double "tabbys
Meselson/Stahl Experiment
Devised an experiment to differentiate between the 3 methods of replication. Used N14 and N15.
Origin of Replication
Start point; Makes a replication bubble that then forms 2 replication forks;
How many origin of replication does bacteria have?
Only 1
How many origin of replication does eukaryote have?
Multiples
DNA Helicase
Separates the strand.
Moves 5' --> 3', and uses ATP to move fork forward;
"donut
DNA topoisomerase
Helps relieve the tension of uncoiling DNA molecule by splicing it and putting it together.
It moves slightly ahead of the replication fork.
"Kusachki
Single Strand Binding Proteins
Keep parental strands open to act as template and keep then from binding back to each other;
"Broccoli
DNA Polymerase
Covalently links nucleotides;
What does DNA Polymerase require to get started?
Needs a primer; DNA Primase makes a primer from RNA
What direction does DNA Polymerase work in?
Only 5' --> 3'
Leading Strand
DNA synthesized as one long molecule;
Goes 5' to 3'
Lagging Strand
Goes 5' to 3' too, but using Okazaki Fragments
Okazaki Fragments
Relatively short DNA segments synthesized on a lagging strand during DNA Replication;
DNA Replication is very accurate. How is the accuracy assured?
1. H-Bond between A-T and C-G is more stable than other combinations;
2. Active site of DNA polymerase is unlikely to form if parirs are mismatched;
3. DNA polymerase proofreads itself;
What are the 3 most important issues for DNA polymerase?
1. Speed;
2. Fidelity;
3. Completeness
Nearly all living species have more than one type of DNA polymerase. Have many do humans have? E.Coli?
E. coli has 5;
Humans have 12 or more;
Telomeres
Series of short nucleotide sequences repeated at the ends of chromosomes in eukaryotes; This along with telomerase makes sure that the lagging strand does not get shorter.
Chromosome
Discreet unite of genetic material;
Chromatin
Chromosomes are composed of chromatin: DNA-Protein complex;
DNA is very tightly packed
Typical eukaryotic chromosome may be hundreds of millions of base pairs long:
Length would be 1 meter
But must fit in cell 10-100�m
DNA wrapping
DNA wrapped around histones to form nucleosome
Shortens length of DNA molecule 7-fold
Q1:Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both th
B) The R strain would be transformed into the virulent S strain and kill the host.
Q2: Which of the following is NOT a criterion for an organism's genetic material?
A) The genetic material must contain information necessary to construct a whole organism.
B) The genetic material must be transmitted from parent to offspring.
C) To transmi
D) The genetic material must be dynamic, changing rapidly in response to changes in the environment.
Q3: Griffith first proposed the "transformation principle" through his studies on Streptococcus pneumoniae bacterium. Which of the following molecules was later found to be responsible for this phenomenon?
A) protein
B) RNA
C) DNA
D) phage
E) bacteriophag
C) DNA
Q4: Who discovered that DNA was the genetic material or transforming factor that could convert nonvirulent R-type Streptococcus pneumoniae bacterium to the virulent S-type?
A) Weismann and Nageli
B) Griffith
C) Avery, MacLeod, and McCarty
D) Hershey and C
C) Avery, MacLeod, and McCarty
Q5: The protein of T2 bacteriophage is labeled with 35S and the DNA with 32P. Where would one detect most of the 32P if the T2 bacteriophage were allowed to infect the bacteria?
A) on the phage coat surrounding the T2 bacteriophage
B) on the membrane of t
D) inside the infected bacteria
Q6: Which of the following scientist-discoveries is mismatched?
A) Watson, Crick, Wilkins, and Franklin-DNA structure
B) Avery, MacLeod, and McCarty-DNA is the genetic material
C) Meselson and Stahl-mechanism of DNA replication
D) Griffith-chromosomes
E)
D) Griffith-chromosomes
Q7: Which of the following relationships about nucleotide composition in DNA is TRUE?
A) C+G=A+T
B) C+A=G+T
C) C=A
D) G=T
E) C=T
B) C+A=G+T
Q8:The building blocks of DNA are _________.
A) genes
B) double helices
C) amino acids
D) nucleotides
E)chromosomes
D) nucleotides
Q9: Which of the following is the highest (or most complex) level of structure for genetic material?
A) nucleotide
B) double helix
C) DNA
D) gene
E) chromosome
E) chromosome
Q10: Beginning with the simplest level of structure, which order of organization of genetic material is CORRECT?
A) DNA, nucleotide, gene, genome, chromosome
B) nucleotide, DNA, gene, chromosome, genome
C) DNA, nucleotide, gene, chromosome, genome
D) nucl
B) nucleotide, DNA, gene, chromosome, genome
Q11: The nucleotides within DNA are composed of a
A) phosphate group, ribose sugar, and nitrogenous base.
B) sulfur group, ribose sugar, and nitrogenous base.
C) phosphate group, deoxyribose sugar, and nitrogenous base.
D) sulfur group, deoxyribose sugar,
C) phosphate group, deoxyribose sugar, and nitrogenous base.
Q12: All of the following nucleotide bases are pyrimidines EXCEPT
A) adenine.
B) thymine.
C) cytosine.
D) uracil
E) cytosine and thymine.
A) adenine.
Q13: Which of the following is FALSE when comparing RNA and DNA?
A) Both are produced by phosphodiester linkages.
B) Both are composed of phosphate groups.
C) Both are composed of sugars.
D) Both are composed of identical nucleotides.
E) Both are composed
D) Both are composed of identical nucleotides.
Q14: What was one of the pieces of evidence most critical to the discovery of DNA structure?
A) its composition of four different nucleotides.
B) its mode of replication.
C) an X-ray diffraction pattern suggesting a double helix shape.
D) the backbone con
C) an X-ray diffraction pattern suggesting a double helix shape.
Q15: Which of the following statements about the structure or composition of DNA is FALSE?
A) DNA is a double helix.
B) Complementary base-pairing occurs between pyrimidine and purine bases.
C) The amount of thymine closely approximates that of guanine wi
C) The amount of thymine closely approximates that of guanine within a particular organism.
Q16: What is the complement DNA strand to 5?-ATTCGGTGA-3??
A) 5?-TAAGCCACT-3?
B) 3?-CGGATTGTC-5?
C) 5?-CGGATTGTC-3?
D) 3?-TAAGCCACT-5?
E) 3?-ATTCGGTGA-5?
D) 3?-TAAGCCACT-5?
Q17: A DNA specimen that contains 30% guanine has ________ thymine.
A) 15%
B) 20%
C) 30%
D) 60%
E) The amount of thymine cannot be determined.
B) 20%
Q18: Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base?
A) guanine
B) cytosine
C) thymine
D) uracil
E) adenine
A) guanine
Q19: Reverse transcriptase is an enzyme that can synthesize DNA from an RNA template. What DNA sequence is produced from an RNA molecule with the sequence 5'AUUGACGGU3'?
A) 3'UAACUGCCA5'
B) 5'TTTCTGCCT3'
C) 3'TAACTGCCA5'
D) 5'ATTCAGCCT3'
E) 3'TUUCTGCCU5'
C) 3'TAACTGCCA5'
Q20: In order to produce a single strand of DNA the nucleotides combine to form what type of bond?
A) hydrogen
B) peptide
C) phosphodiester
D) purine
E) ionic
C) phosphodiester
Q21: The mechanism of DNA replication is
A) conservative.
B) intermediate.
C) semiconservative.
D) dispersive.
E) complementary.
C) semiconservative.
Q22: Bacteria are grown in 15N (heavy) medium and then transferred to 14N (light) medium and are allowed to replicate for 1 generation. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient band(s)?
A) one hea
C) one half-heavy (intermediate to heavy and light) band
Q23: Bacteria are grown in 15N (heavy) medium and then transferred to 14N (light) medium and are allowed to replicate for 2 generations. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient band(s)?
A) one he
E) one light and one half-heavy band
Q24: Which of the following is NOT a protein involved in DNA replication?
A) replication fork
B) single-stranded binding proteins
C) DNA ligase
D) topoisomerase
E) helicase
A) replication fork
Q25: During DNA replication, all of the following proteins are important for separating the DNA strands and allowing movement of the replication fork EXCEPT
A) DNA polymerase.
B) helicase.
C) topoisomerase.
D) single-stranded binding proteins.
E) both hel
A) DNA polymerase.
How many replication forks are there at an origin of replication?
A) 1
B) 2
C) 3
D) 4
E) 5
B) 2
Q27: ______________ are made in replicating the lagging strand of DNA, but are not made during leading strand DNA replication.
A) primers
B) nucleases
C) Okazaki fragments
D) pyrophosphates
E) DNA polymerases
C) Okazaki fragments
Q28: Which of the following statements best describes DNA polymerase?
A) It is an enzyme required to produce a primer needed for DNA replication.
B) It is an enzyme that catalyzes the addition of nucleotides to the 5? end of a growing DNA strand.
C) It is
A) It is an enzyme required to produce a primer needed for DNA replication.
Q29: Which molecule catalyzes covalent bond formation between fragments of DNA.
A) helicase
B) ligase
C) polymerase
D) primase
E) nuclease
B) ligase
Q30: All of the following are critical factors for DNA replication on the leading strand EXCEPT?
A) primer
B) DNA ligase
C) DNA polymerase
D) DNA primase
E) deoxynucleoside triphosphates
B) DNA ligase
Q31: Which molecule is responsible for separating double-stranded DNA into single strands?
A) DNA primase
B) DNA helicase
C) topoisomerase
D) DNA ligase
E) single-stranded binding proteins
B) DNA helicase
Q32: ________ produces short sequences of RNA, which allows polymerase to synthesize a new strand of DNA.
A) DNA primase
B) DNA helicase
C) DNA polymerase
D) DNA topoisomerase
E) DNA ligase
A) DNA primase
Q33: The function(s) of DNA polymerase includes which of the following?
A) DNA synthesis
B) DNA proofreading
C) removes RNA primers and fills in the gaps
D) DNA synthesis and proofreading
E) DNA synthesis, DNA proofreading, and removes RNA primers and fil
E) DNA synthesis, DNA proofreading, and removes RNA primers and fills in the gaps
Q34: Which of the following statements about DNA replication is INCORRECT?
A) It begins at multiple origins of replication sites along eukaryotic chromosomes.
B) It proceeds with the addition of new nucleotides to the 3? end of a growing DNA strand.
C) It
C) It is powered by the hydrolysis of ATP.
Q35: Which of the following proteins-functions is mismatched?
A) DNA polymerase-DNA synthesis
B) DNA polymerase-primer removal and replacement with DNA
C) DNA primase-production of RNA primer
D) topoisomerase-separates double-stranded DNA into single stra
D) topoisomerase-separates double-stranded DNA into single strands
Q36: Why is there a need to produce Okazaki fragments on the lagging strand, but not on the leading strand of DNA?
A) The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5? to 3? direction only.
B) It is substantially more
E) The leading strand opens first, and so Okazaki fragments are not needed. The lagging strand unwinds second resulting in the need to produce Okazaki fragments.???
Q37: The enzyme that attaches DNA sequences at the ends of eukaryotic chromosomes in order to prevent chromosome shortening is called _____.
A) Polymerase
B) Ligase
C) Teloisomerase
D) Topoisomerase
E) Primase
C) Teloisomerase
Q38: Which of the following statements about telomeres is INCORRECT?
A) Telomeres are produced by telomerase.
B) Telomeres are found at the ends of chromosomes.
C) Telomeres are short repeat sequences.
D) Telomeres would be longer in cells of older than y
D) Telomeres would be longer in cells of older than younger individuals.
Q39: Where would one expect to find the most telomerase?
A) male germ cells that give rise to gametes
B) skin cells from a 60-year-old individual
C) skin cells from a 2-year-old individual
D) a nerve cell from a 60-year-old individual
E) a nerve cell from
A) male germ cells that give rise to gametes
Q40: During the DNA replication process, which of the following organisms would have the fewest origins of replication per cell?
A) a rapidly dividing Streptococcus bacterium
B) a yeast cell
C) a human
D) a young oak tree
E) a fruit fly
A) a rapidly dividing Streptococcus bacterium
Q41: Which of the following characteristics of genetic material accounts for the phenomenon of natural selection?
A) Information
B) Replication
C) Transmission
D) Replication and Transmission
E) Variation
E) Variation
Q42: Which of the following characteristics of genetic material accounts for the need to get a flu vaccine every year, but a polio vaccine once in a life time?
A) Information
B) Replication
C) Transmission
D) Replication and Transmission
E) Variation
E) Variation
Q43: Which of the following functions of genetic material accounts for the rapid growth of cancer cells?
A) Information storage
B) Ability to replicate
C) Transmission to the next generation
D) Ability to replicate and transmission to the next generation
D) Ability to replicate and transmission to the next generation
Q44: Which of the following functions of genetic material accounts for the appropriate expression of proteins?
A) Information storage
B) Ability to replicate
C) Transmission to the next generation
D) Ability to replicate and transmission to the next gener
A) Information storage
Q45: Which of the following functions of genetic material accounts for the high level of protection it is afforded by eukaryotic cells, such as multiple DNA repair mechanisms and storage within the double membrane of the nucleus
A) Information storage
B)
A) Information storage
Q46: Which of the following functions of genetic material accounts for hemoglobin proteins to be expressed in blood (bone marrow) and myoglobin proteins to be expressed in muscle tissue?
A) Information storage
B) Ability to replicate
C) Transmission to th
D) Ability to replicate and transmission to the next generation
Q47: Which of the following statements is FALSE?
A) One chromosome is made up of many DNA molecules
B) A eukaryotic genome is made up of many DNA molecules
C) A DNA double helix is composed of both covalent bonds and hydrogen bonds
D) A strand of DNA is m
A) One chromosome is made up of many DNA molecules???
Q48: Without the work of Rosalind Franklin, Watson and Crick would not have known
A) Which nucleotides could pair together
B) How many strands of DNA made up the molecule
C) The shape of the molecule xxx
D) The width of the molecule
E) All of the above
E) All of the above
Q49: Without data from the base composition studies of Chargoff, what might Watson and Crick's modeling studies have erroneously concluded?
A) Bases could pair with themselves (e.g. A with A, C with C)
B) Any purine could pair with any purine
C) Any pyrim
E) Any purine could pair with any pyrimidine
Q50: Which of the following statements is TRUE?
A) The leading strand is replicated continuously for the entire length of the chromosome, while the lagging strand has multiple origins of replication
B) The lagging strand is synthesized in a semiconservati
A) The leading strand is replicated continuously for the entire length of the chromosome, while the lagging strand has multiple origins of replication???
Q51: Some bacteria have been found to have much higher rates of mutation than other members of their populations; they are termed "mutators." What do you think is the reason for their faster rates of mutation?
A) They have much smaller genomes than regula
D) Their DNA polymerase has compromised 3' to 5' exonuclease function.???
Q52: Which of the following statements in TRUE?
A) Interphase chromosomes are loosely compacted, overlapping, and intertwined with each other within the nucleus.xxx
B) Interphase chromosomes are loosely compacted and do not associate with histones until t
B) Interphase chromosomes are loosely compacted and do not associate with histones until the cell is preparing to divide.???
Q53: Which of the following statements in TRUE?
A) Many active genes are found in heterochromatin, because proteins involved in transcription can easily access these regions of DNA. xxx
B) Many active genes are found in euchromatin, because proteins invol
B) Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA.???