Three parts of a DNA nucleotide
Phosphate Deoxyribose sugar Nitrogenous base
How does an RNA nucleotide differ from a DNA nucleotide?
DNA nucleotides, or deoxyribonucleotides, have a deoxyribose sugar that lacks an oxygen molecule at the 2' carbon of the sugar molecule. Ribonucleotides, or RNA nucleotides, have a ribose sugar with oxygen linked to the 2' carbon of the sugar molecule. Ribonucleotides may contain the nitrogenous base *uracil* but NOT the thymine. DNA nucleotides contain *thymine*, but not uracil.
Draw the three parts of a DNA nucleotide.
Draw the difference between an RNA nucleotide vs DNA nucleotide.
a more stable double-stranded form that stores the genetic blueprint for cells
DNA
a more versatile single-stranded form that transfers the genetic information for decoding
RNA
two types of nucleic acids present in cells
DNA and RNA
Both DNA and RNA are ______ of nucleotides
polymers
How does a purine differ from a pyrimidine?
A purine consists of a six-sided ring attached to a five-sided ring.
What purines and pyrimidines are found in DNA and RNA?
In both DNA and RNA, the purines found are adenine and guanine. DNA and RNA differ in the pyrimidine content. The pyrimidine cytosine is found in both RNA and DNA., However, DNA contains the pyrimidine thymine, whereas RNA contains the pyrimidine uracil but not thymine.
Draw a purine vs pyrimidine.
Draw a short segment of a single polynucleotide strand, including at least three nucleotides. Indicate the polarity of the strand by identifying the 5' end the 3' end.
Which bases are capable of forming hydrogen bonds with each other?
Adenine is capable of forming two hydrogen bonds with thymine. Guanine is capable of forming three hydrogen bonds with cytosine.
Name the purines.
Think "GAP".
Guanine and Adenine are the purines.
Name the pyrimidines.
Think "CUT to the rim".
Cytosine, Uracil and Thymine.
Adenine
Guanine
Cytosine
Thymine
Uracil
One nucleotide strand of a DNA molecule has the base sequence illustrated below.
5'--ATTGCTACGC--3'
Give the base sequence and label the 5' and 3' ends of the complementary DNA nucleotide strand.
5'--ATTGCTACGC--3'
3'--TAACGATGCG--5'
If a double-stranded DNA molecule is 15% thymine, what are the percentages of all the other bases?
15% thymine = 15% adenine
35% guanine = 35% cystosine
What functions does supercoiling serve for the cell?
Supercoiling compacts the DNA. Negative supercoiling helps to unwind the DNA duplex for replication and transcription.
Any group of basic proteins found in chromatin
histones
A structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones
nucleosome
the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.
chromatin
An enzyme that cleaves the chains of nucleotides in nucleic acids into smaller units
nuclease
The nucleosome core particle contains two molecules each of histones. These histones are ___, ____, ____, and ____.
H2A
H2B
H3
H4
The nucleosome core particle contains two molecules each of histones, which form a protein core with ___ - ____ bp of DNA wound around the core.
145-147
For each nucleosome, one molecule of a fifth histone, ___, binds to ___ entering and exiting the nucleosome core to clamp the DNA around the nucleosome.
H1; DNA
each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA.
chromatid
Describe in steps how the double helix of DNA, which is 2nm in width, gives rise to a chromosome that is 700 nm in width.
DNA is first packaged into nucleosomes; the nucleosomes are packed to form a 30-nm fiber. The 30 nm fiber forms a series of loops that pack to form a 250-nm fiber, which in turn coils to form a 700-nm chromatid.
Describe the function of the centromere. How are centromeres different from other regions of the chromosome?
Centromeres are the points at which spindle fibers attach to the chromosome. They are necessary for proper segregation of the chromosomes in mitosis and miosis.
Nucleosomes at centromeres often possess the variant histone ____.
CenH3
The variant histone CenH3 promotes the formation of the _________ to which spindle fibers attach.
kinetochore
________ are the ends of the linear chromosome in eukaryotes.
Telomeres
Why do telomeres cap and stabilize the ends of the chromosomes?
To prevent degradation by exonucleases or joining of the ends.
Telomeres also enable ______ of the ends of the chromosomes by an enzyme called _____.
replication; telomerase
The telomeric DNA sequence consists of repeats of a simple sequence, usually in the form of ______.
5'C_n(A/T)_m
performed the first chemical analysis of DNA; Isolated “nuclein” from white blood cells (1880’s)
Johann Friedrich Miescher
Who found that DNA was essentially a long-chain molecule, made up of four different nucleotides, a ribose sugar, and phosphate?
Phoebus Levene
Proteins are composed of up to ___ amino acids
20
DNA is composed of __ nucleotides
4
Draw the three parts of an RNA nucleotide.
The theory that suggested that equal amounts of the four nucleotides were present in all cells
Tetranucleotide Theory
•Proteins are composed of up to ___ amino acids
20
DNA is composed of __ nucleotides
4
In transformation, bacterial cell absorbs DNA from its ________.
environment
What are the three processes of gene transfer in bacteria?
Conjugation, transformation, and transduction
What is the nucleotide structure in A and B.
Ribose; Deoxyribose
Both the ribose and deoxyribose have an OH group on the 5-carbon sugar. What position is it in?
3' carbon
Both the ribose and deoxyribose have attached a PO4 group on the 5-carbon sugar. What position is it in?
5' carbon
What is the charge of DNA?
Negative
Why is DNA negatively charged?
The phosphate group is highly negatively charged.
The phosphate group consists of what?
Phosphorous and 4 oxygen molecules.
Name each phosphate group in A, B, and C.
A: Monophosphate
B: Diphosphate
C: Triphospate
In a nucleotide structure, the bases are nitrogen-containing ring compounds that are either ________ or ______.
pyrimidines; purines
A cyclic nitrogenous base has which atoms?
Nitrogen, Carbon, Hydrogen, and Oxygen
What type of deoxyribonucleotide structure is this?
Deoxythymidine 5'-monophosphate
(dTMP)
What type of deoxyribonucleotide structure is this?
Deoxycytidine 5'-monophosphate
(dCMP)
What type of deoxyribonucleotide structure is this?
Deoxythymidine
5'-monophosphate
(dTMP)
What type of deoxyribonucleotide structure is this?
Deoxycytidine
5'-monophosphate
(dCMP)
What material makes up the chromosomes?
Chromatin
What is chromatin?
DNA + Protein.
It is what makes up the chromosomes.
What are the criteria for the genetic material?
Coding
Replication
Expression
Mutation
Who isolated the "nuclein" from white blood cells in the 1880s?
Johann Friedrich Miescher
What does virulent mean?
Causes disease.
What does avirulent mean?
It does not cause disease.
When Mr. Griffith was conducting transformation experiments by injecting mice with either the live S bacteria or the live R bacteria, what was the conclusion?
Live S causes disease.
Live R does not cause disease.
When Mr. Griffith was conducting transformation experiments by injecting mice with heat-killed S bacteria, what was the conclusion?
Heating destroys the disease-causing component in S bacteria.
When Mr. Griffith was conducting transformation experiments by injecting mice by mixing live type R and heat-killed S bacteria, what was the conclusion?
Type R bacteria were transformed into disease-causing S bacteria.
What is protease?
The enzyme that degrades proteins.
The enzyme that degrades DNA is...
deoxyribonuclease
Enzyme that degrades RNA
RNase: Ribonuclease
Avery, MacLeod, and McCarty's experiment proved that heat alone did not kill the S bacteria. What was the transforming material?
DNA had to be destroyed.
What is semi-conservative replication of DNA?
The new DNA is half old, half new.
What enzyme chains most nucleotides together in bacterial DNA replication?
DNA Polymerase III
What enzyme chews up the RNA primer and replaces the nucleotides deoxynucleotides?
DNA Polymerase 1
What enzyme creates a bond on the sugar-phosphate backbone so the new strand is fully chained together?
DNA Ligase
What enzyme sits right in the replication fork while breaking hydrogen bonds between base pairs?
DNA Helicase
Which gene transfer deals with bacterial cells absorbing DNA from its environment?
transformation
What form of DNA is the most common form found in cells?
B cells
Who made the first X-Ray Crystallography images of DNA?
Franklin
Who Analyzed purine and pyrimidine content of DNA from several species?
Chargaff
Who did experiments to determine if protein or DNA caused virus infection of bacteria?
Hershey & Chase
Who did the first experiments on pneumonia infection of mice with rough or smooth bacteria that were live or heat-killed?
Griffith
Which of these statements about nucleosomes is FALSE?
A) Approximately 145 nucleotide pairs of DNA are wrapped around a nucleosome with another 50 nucleotide pairs linking it to the next nucleosome
B) A nucleosome core is an octomer of 2 molecules each of Histones H2A, H2B, H3 and H4
C) Histone H1 is on the outside of the nucleosome core
D) Histones self-assemble into nucleosomes as the DNA wraps around it
E) Nucleosomes are found in cells of bacteria, plants and animals
E
