Lecture 5 Flashcards
[Year] - [Scientist] concept of hereditary factor
-chemical composition was not yet known and understood
1865 - Gregor Mendel
[1930] - [Scientist]
2 view points about genes
1. Gene is just a hypothetical entity
2. Gene could be a chemical compound
R.A. Fisher
What are the three components that make up the chemical composition of a chromosome
Lipids, Proteins, and Nucleid
A component of chromosome found in interphase chromosomes, metaphase chromosomes, and nucleic matrix
Lipids
A type of protein which is responsible for packing the DNA (chromatid-chromosome)
Histones or Protamines
a type of protein that make up the scaffold upon which chromatin loops are anchored
Non-histone chromosomal protein
2 types of nucleic acid
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
DNA is the genetic material of all living organisms except for some _____
Viruses
genetic material of some viruses
RNA
What are the characteristics of a good genetic material according to H.J Miller
- Contain all the necessary biological information
- Mutation is duplicated
- Stable molecular structure with low frequency of mutation
- Can transmit information from one generation to another
- Stored information must be decoded and translated into action
- Can duplicate itself with extra fidelity
DNA can duplicate itself with extra fidelity, how many identical copies are produced during 1 round of replication that can be distributed during M phase?
2 identical copies
T or F: Mutation is not inherited and is no a source of variation
F: Opposite
1830s
Proteins: ___________
Proteios: “______”
Proteins: most important molecule
Proteios: “of first importance”
1860s F. Miescher
-Isolated molecule from nucleus: _______ while characterizing proteins from ______
nuclein
pus cells
1866 E. Haeckel
Discovered: most obvious cellular component of the cell is the
nucleus
1895 E. Wilson
Observed: important nuclear element handed from one cell to another cell is the ________
DNA
1928 F. Griffith
Conducted _______ experiment using Streptococcus pneumoniae
Two strains: _______ (R) stain and ______ (S) strain
transformation
Avirulent (R) stain and Virulent (S) stain
In 1928 during the transformation experiment of F. Griffith different set up showed that the _____ stain transformed into the _______ stain which declared the presence of the transforming principle
R stain transfromed into the S stai
what is transformation?
uptake of genetic material from the surroundings
Heat kills virulence of S cells. When injected to the mouse, it cause the mouse to become healthy. However, when mixed with living R cells, what occurs which cause the mouse to die?
transformation of R cells into S cells
1944 O. Avery, C. Macleod, and M. McCarty
identified the transforming principle (TP) as ______
DNA
1944 O. Avery, C. Macleod, and M. McCarty
When the transforming principle was treated with proteinases and RNAses ______________ retains hence TP is not protein nor RNA
transforming ability
1944 O. Avery, C. Macleod, and M. McCarty
When TP was treated to remove protein and RNA, the composition of substance left _________________ of ____________
matched composition of DNA
1952 A. Hershey and M. Chase
Proved: DNA is genetic material of ____________ (phages)
DNA is labeled with P32 while the protein coat is labeled with S35
bacterial viruses
What is the blender experiment?
Blender separates phages from bacteria after infection
P32 label was present in bacteria after phase infection
-Proves that DNA is injected into cell while protein coat remained outside
1952 N. Zinder, J. E. Lederberg
Performed __________ experiment on Salmonella typhimurium
transduction
What is transduction?
process wherein bacterial cell can take up DNA through recombination that was introduced by phages
-injection of DNA to the bacterial cell through phages
Main contributors of the elucidation of the DNA structure in 1953
F. Crick, J. Watson, R. Franklin, M. Wilkins
F. Crick
involved in development of ___________ and ______________
PHD: Xray studies on proteins
radar and magnetic mimes
J. Watson
-Child prodigy
-Did labeling of _________
phage DNA
M. Wilkins
-Worked on _________ of DNA
Xray diffraction
R. Franklin
-Expert on Xray diffraction technique
-Worked on Xray diffarction of DNA
-Captured famous _________ showing xray diffraction - provided essential information for developing a model of DNA
photograph 51
who shared the photo 51 and research to Crick and Watson without Franklin Knowing?
Wilkins
a process wherein xrays are projected towards a substance and the atoms in the substance would deflect the rays and create an image produced by the DNA molecule
Xray Diffraction
1951-1952 R. Franklin, Gosling, & M. Wilkins
-______ DNA structure (orientation)
-Sugar and Phosphate _______ (where)
-Nucleotides ______ (where)
helical
outside
inside
1953 J. Watson and F. Crick
________ helix (Single, Double, Triple) - From Pauling
Phosphate in __ (where) Fr
Triple
Center
early 1950
L. Pauling
_______ helix DNA (Single, Double, Triple)
Triple
J. Griffith
Nucleotides are ______ (shape) and placed _______ of each other
Calculations show possiblity of base pairing between A and T and C and G
Flat; atop
E. Chargaff
DNA of all cells contained ____ amounts of A and T and _____ amounts of C and G
equal
Chargaff’s Rule: Ratio of purine-pyrimidine is ______
evidence for specific pairing
1:1
J. Donohue
-________ in the bases can change its position
-Possibility for ________ bonding
H (hydrogen)
Hydrogen
DNA
molecular basis of ________-
_______ of all living organisms
double helix structure composed of a __________ backbone and ________ on the inside
heredity
genetic material
sugar-phosphate; base pairs or nitrogenous bases on the inside
DNA is a ____________ polymer with deoxyribonucleotides
nucleic acid
what are the monomers of DNA or nucleic acid
nucleotides
bonds that connect nucleotides
phosphodiester bonds
nucleoside is composed of two which are
sugar and nitrogen base
what is the sugar of DNA?
2-deoxyribose
Purines nitrogen bases
Guanine and Adenine (PUGA)
Pyrimidine Nitrogen Bases
Cytosine and Thymine (Not PUGA)
A nucleotide contains three which are
Phosphate Group
Sugar
Nitrogen Bases
give the negative charge of the DNA
Phosphate Group
Important for coiling into condensed structure; component of the DNA
phosphate group
what is the charge of histones?
Positive (they are positively charged proteins)
proteins that bind to DNA to coil it
histones
the sugar molecule, 2-deoxyribose is connected to the SUGAR molecule through a bond called
phosphoester bond
the sugar molecule, 2-deoxyribose is connected to the nitrogenous bases through a bond called
Beta-N-glycosidic bond or simply just glycosidic bond
difference between the sugar of DNA and RNA
DNA - nucleotide has 2 deoxyribose
RNA - only ribose sugar
no. of rings of
purine: ___________
pyrimidine: ________
purine: 1 ring
pyrimidine: 2 rings with the addition of U or Uracil
what is the bond between A and T
double bond
bond between C and G
triple bond
base pairs have similar structures: T or F?
True
Alphabet of DNA - our genes are written by alphabet that are represented by the _________ (component of a nucleotide)
nitrogen bases or base pairs
bond between sugar and phosphate group and hydroxyl group (C-O-P-O-C)
phosphoester group
bond between two nucleotides
phosphodiester bond
bond that joins a carbohydrate (sugar) molecule to another group
glycosidic bond
components of DNA that is constant in every molecule and found outside
sugar and phosphate group
components of the DNA that is not constant in every DNA molecule and found inside
nitrogen bases
who developed the Chargaff Rule
Erwin Chargaff
Features of the DNA
1. It is composed of ________ polynucleotide stands connected via __________ of bases
2. Sugar:_________
3. Antiparallel - ______, ____
4. Complementary Specific Pairing
A pairs with T and C pairs with G
5. Forms a ______ colil (shape)
- 2; hydrogen bonding
- 2 deoxyribose
- 5’-3’, 3’-5’
- helical
1 nm = ___ armstrong
how many nm are there in 78 armstrongs?
7.8
Diameter of DNA molecule
2nm or 20 A
how many base pairs are there in each turn of DNA
10 base pairs
how many nm and armstrong in each turn of DNA
3.4 nm/34A
For each base pair in a DNA, how many nm?
0.34nm
two DNA strand are held together by
hydrogen bonds
sugar phosphate backbone is held together by
phosphodiester bonds
base stacking are done through ________
hydrophobic interactions
are the nitrogen bases of the DNA polar or nonpolar?
nonpolar
base stackings adds _____ to the entire molecule
stability
the environment where the DNA can be found is hydrophobic/hydrophilic
hydrophilic
direction of the DNA sequence
5’ to 3’ (parallel)
in a DNA carbon 5 has an attachment of _______ and Carbon 3 has _____
Carbon 5: Phosphate
Carbon 3: OH
Cells read DNA sequences from ____- to ________
5’ to 3’
the sequence 5’-TGCA-3’ is not the same as5’-ACGT-3’ why is this so?
because the base pairs are different
Is DNA a static molecule?
No, it is dynamic and change according to the needs of the cells
most common conformation of the DNA
B-DNA
-RIGHT HANDED HELIX
a type of conformation of DNA that is
right handed but much more compact
11 base pairs per turn
occurs in dehydrating conditions
A-DNA
how many base pairs are there in A-DNA?
11 base pairs
a type of DNA conformation that is
left handed
unstable experience: from when genes are transcribed and disappears through topoisomerase activity after the gene is no longer transribed
Z-DNA
the left part of the DNA is in the _______ to _______ direction
5’ to 3’ (parallel)
the right part of the DNA is in the __________ to _________ direction
3’ to 5’ (antiparellel)
EVIDENCES THAT THE DNA IS THE GENETIC MATERIAL
1. Relative constancy of DNA in all ____ tissues
Starvation = DNA unchanged
2. ____ cells have half amount of DNA in diploid
3. Double of DNA content at ____ phase
4. Cells with extra sets of __l)____ have a propoirtional increase in DNA content
5. Parallelism of ________ absorption with mutation rates
6. ___________ AND _________ in bacteria (two processes discussed before)
7. Production of new ______ particles in bacterial cells
8. RNA content of TMV caused infection and not the ____ (Viruses can either have DNA/RNA as the genetic material)
- Diploid
- Haplod
- S phase
- chromosomes
- UV radiation
- Transformation and Transduction
- Viral/Virus
- protein coat
what is the difference between Polyploidy and polyteny
Polyploidy - more number of chromosomes
Polyteny - more number of sister chromatids/chromatids
All organisms have ____ as genetic material. However some viruses can have _______
DNA;RNA
an RNA is composed of ________ polynucleotide strand (number)
1
what is the sugar of RNA?
D-Ribose
What is the difference between DNA and RNA when it comes to the attachment of oxygen of the ribose?
DNA - no oxygen attached in the deoxyribose
RNA -oxygen attached in the ribose
flowchart of process for the DNA replication
2 strands - unwind/separate - base pair - production of 2 identical DNA
What is the model of DNA replication?
semiconservative
-each daughter DNA contains one new strand and one old strand from parental template
Grew E.coli: nitrogen source consisted of only 15NH4CL.
- 15N-containing cells were transferred to growth media
containing 14N isotopes
- After 1 cell division only one band was observed to
occur between where 15N-DNA and 14N-DNA bands
would normally appear
- RESULT: new DNA was a hybrid molecule containing
15N strand and 14N strand
- After 2 cell division:
- 2 discrete bands: 1 made of 14N- 14N DNA an
Meselson and Stahl Experiment
a model of DNA replication where the parental double helix remains INTACT and a second, all new-copy is made
Conservative model (k: INTACT)
a model of DNA replication where the two strands of the parental molecule separate and each functions as a TEMPLATE
Semiconservative model (k:TEMPLATE)
a model of DNA replication where each strand of both daughter molecules contain a MIXTURE of old and new synthesized parts
dispersive model (k: MIXTURE)
initiation starts with_______ (origin of replication)
typically has a lot of ___ pairings
-The are easier to break due to only having ____ h bonds (no.)
-There are multiple origins in the cell happening at the same time
-Formation of ___ stranded DNA templates
orisite
A-T
2
single
Proteins or Enzymes in Initation
Helicase
SSBPS (single stranded binding proteins)
DNA gyrase/Topoisomerase
an enzyme in initiation which separate 2 strands of DNA
Helicase
a protein in iniation which maintains the 2 single stranded templates
-protects it from enzymes like nucleases that breaks phosphodiester bonds
SSBPS(SINGLE STRANDED BINDING PROTEINS)
an enyzme in initiation which is needed to relax tension brought by the unbinding of DNA at the fork
nuclease domain: cuts DNA
ligase domain: restitches cut area
DNA gyrase
key enzyme for replication
DNA polymerase
main enzyme that catalyzes the synthesis of new strands, adds DNA nucleotides to primer
DNA polymerase
enzyme that dominantly adds DNA nucleotides to primer
DNA polymerase
where are nucleotides added? 5’ or 3’
3’ end
in Elongation and Replication you need a RNA ___ to proceed
primer
synthesis of DNA strand is always in the ___ to ____ direction
5’ to 3’ direction
an enzyme that adds RNA primer in elongation
primase
direction of the leading strand
3’ tp 5’ parental strand (antiparallel)
K: 3 LEAD
How many primer is needed in the leading strand? since it can synthesize continuously
1 RNA primer only
Leading strand
Eukaryotes: 11 +/-1 nucleotides long
Prokaryotes - 10 - 60 nucleotides long
number of nucleotides in leading strand
In leading and lagging strand the direction for the following are always:
Proofreading -
Synthesis -
Proofreading: 3’ to 5’
Synthesis - 5’ to 3’
direction of the lagging strand
DNA Pol III: 5’ to 3’ parental strand direction
direction of the lagging strand
DNA Pol III: 5’ to 3’ parental strand direction
lagging strand requires ____ primers (adverb of quantity) since they cannot synthesize continuously
several/many/ a lot
Okazaki fragments:
Prokaryotes - approx. 1000 - 2000 nucleotides long
Eukaryotes - approx 100 to 200 nucleotides long
no. of okazaki fragments in lagging strand
K: thousands first 1-2
hundreds 1-2
enzymes and proteins in Elongation
DNA polymerase
Primase
DNA Pol I
Ligase
enzyme that removes RNA primers and fills gap left by primers since RNA primase cannot stay in DNA molecules
DNA Pol I: K: LEFT BY PRIMERS
DNA POL I removes RNA primer in ____ direction exonuclease activty
5’3 direction K: remove and synthesize direction 5’ to 3’ same lang
what is the indicator that replication will now terminate?
-can be initiated by protein for termination or because of structure of replication site
when 2 identical molecules are produced
this is released when nucleoside triphosphate binds with OH end, releasing 2 phosphates
Pyrophosphate
The simultaneous syntehsis of leading and lagging strands (new model or looping) is catalyzed by the enzyme
replisome
replisome is composed of DNA pol III (enzyme) which acts as pairs with 2 catalytic cores: primosome (____ + ____)
helicase + primase (K: HP Laptop)
when do telomeres get shorter?
as DNA replicates repeatedly through our lives
what END of the DNA is molecule is the longer side 3’ or 5’?
3’
Telomeres (do/do not) code for RNA genes to prevent gene loss
do not code
Upon splitting, DNA polymerase cannot add at the complementary strand with extended and because there is no free ___ end
3’ OH end
this refer to the maximum amount of times the DNA can replicate before genes can become affected (shortening of telomeres)
Hayflick Limit
enyzme that lengthens telomere of linear ends
-complex of proteins and RNA templates
Telomerase
telomerase elongate the ____ end used to extend other strand
3’ end
what is the common telomore end in nucleotides?
TTAGGG PAIRS WITH AAUCCC
Significant of Replication
-faithful copying of DNA to produce 2 ___________ molecules
-identical to each other and ___ molecule
-transmit biological information from parent cell to daughter cells (generation to generation)
cell division cannot occur without replication of DNA
2 DNA molecules
parent molecule
can cell divison occur without the replication of DNA?
NO
Mechanism of High Precision Replication
1. Specificity of base pairing
2. Proof-reading ability of DNA polymerases
3. Excision/Removal repair mechanisms
Mechanism of High Precision Replication
enzyme responsible for the repair of thymine dimer (thymine pairs with each other)
-excision and filing
Endonuclease
enzyme responsible for the hydrolysis of bond between damaged base and sugar
N glucosidase activity
Chromosome Organization
Prokaryotic Chromosome
Double Stranded
approx _____ um long or __ mm
-4x10^6 bp (1kb =1000bp)
-amount of DNA is approx. 1000x the length of E. Coli
11,000 um long or 1.1 mm
which is longer in chromosome organization? Prokaryotic or Eukaryotic
Eukaryotic Chromosomes
contains the genetic material of prokaryotes
nucleoid
how many independent domains are there in the packing of prokaryotes
10 independent domains
packing of prokaryotes contains about 10 independent domains
each loop is about ________ bp (40kb) of supercoiled DNA
40,000
Packing of Prokaryotes
Histone like protein (protein _)
Protein for DNA packing (Protein _)
Histone like protein - protein Hu
Protein for DNA packing - Protein H
how many chromosomes are there in a eukaryotic cell?
46
what is the actual DNA LENGTH
6ft (from end to end)
how many bp are there in a eukaryotic chromosome?
5500000000 (5.5x10^9)
how many cm is 1 chromosome?
7.2 cm (0.01 mm length)
Recite or discuss the chromosome packing
Nucleosome formation - DNA + histone proteins
Chromatosome formation - nucleosome + histone octamer
Solenoid Formation - 6 nucleosomes per coil which forms the chromatin thread 30 nm chromatin fiber
Loop formation which is 300 nmn in length