Genetics MIDTERM
No, cleavage of dNTP drives the formation of the covalent bond between the nucleoside monophosphate and the growing DNA strand.
You are in the lab trying to synthesize DNA in vitro. You are upset because the lab seems to be out of dNTPs (deoxynucleoside triphosphates) but you find a tube of dNMPs (deoxynucleoside monophosphates) in the freezer. You add this to your replication reaction instead of dNTPs. Will your reaction work? Why or why not?
You should confirm that your sample has helicase and primase activity, but not the ability to synthesize DNA.
You are performing a biochemical purification of enzymes involved in DNA replication. You have purified the replisome. You wish to purify the primosome. You perform further separation techniques on your purified replisome. How will you test to determine that you have purified the primosome?
DNA Ligase
_______ attaches adjacent Okazaki fragments, forming a continuous DNA strand
DNA polymerase I
________ fills in small regions of DNA where the RNA primers were located.
polypeptide
a gene is a segment of DNA that has the information to produce a functional product. the functional product of most genes is
DNA has deoxyribose and RNA has ribose and DNA has Thymine and RNA has uracil
a key difference between the nucleotides found in DNA and those in RNA is that
uracil
a nitrogen-containing base found in RNA and not DNA
allele
a variation of a gene is called an
Okazaki fragments
assist in the synthesis of the lagging strand
protease
avery used the enzyme _______ to remove the proteins from the cell extracts
gene
basic unit of heredity
Adenine and guanine
cells are treated with a drug that blocks purine synthesis. which bases would not be made in those treated cells?
small variations in nucleotide sequence of the DNA
genetic variation is ultimately base upon
5'-------DNA polymerase------->3' 3'----------------------------------5'
here are two strands of DNA --------------------DNA polymerase-------> ----------------------------------------------- the one on the bottom is the template stand. label the 5' to 3' direction
catabolic enzymes
if a carbohydrate is going to be broken down for energy, which of the following molecules would be directly involved in the breakdown
population
if a geneticist is studying the prevalence of a trait in a species, they are at the ________ level of study
thymine
in a double helix DNA strand, the adenine on one strand forms a Hydrogen bond with a ________ on the other strand
1'/5'
in a single nucleotide, the base is always attached to the _______ carbon atom of the sugar, and one or more phosphate group are attached at the ______ carbon atom of the sugar molecule
homologs
in many organisms, one set of chromosomes comes form the maternal parent and the other set comes from the parental parent. similar chromosomes in these sets are
DNA
is a macromolecule
DNA polymerase III
is an example of a processive enzyme
an mRNA
is not a constituent of a cell's proteome
DNA topoisomerase I
relax negative supercoils
phosphodiester bond
the bond that makes up the backbone of DNA molecule
specify the amino acids within a polypeptide
the function of the genetic code is to
conservative
the mechanism of DNA replication in which both parental strands remain together following replication?
molecular
the study of the processes of transcription and translation is at the _______ level of biological organization
-gene mutation -alterations in chromosome structure -variations in chromosome number
variation in the traits of organisms may be attributable to...
terminator
where does the process of transcription end?
Promoter
where does the process of transcription initiate
Nucleoid
where is the bacterial chromosome located?
restrictions placed on DNA polymerase
- DNA polymerase can attach new nucleotides only in the 5' to 3' direction -DNA polymerase must begin synthesis using an RNA primer -DNA polymerase must have a template strand to copy from
double helix DNA
- has directionality - the strands are arranged in an anti-parallel arrangement - the strands are complementary
Function of telomeres in eukaryotic chromosomes
- prevent translocation - prevent chromosome shortening - protect chromosome against exonuclease enzymes
DNA gyrase
- promotes negative supercoiling - relaxes positive supercoils - cuts DNA strands as part of its function
False
A DNA strand can be described as antiparallel but un-complementary
-some repetitive sequences - one origin of replication -a few thousand genes
A bacterial chromosome typically contains
somatic cell
A cell that makes up the body structure of an organism and is diploid is
trait
A characteristic that an organism displays is called.
B DNA is right-handed, whereas Z DNA is left-handed.
A key difference between B DNA and Z DNA is that
it is a nucleotide and is found in DNA.
A molecule contains adenine, deoxyribose, and one phosphate. Is it a nucleoside or a nucleotide? Would it be found in DNA or RNA?
DNA and histone proteins
A nucleosome is a combination of
2,3
Adenine and thymine bases are held together by ____ hydrogen bonds, while cytosine and guanine bases are held together by ______ hydrogen bonds
At the molecular level, a gene (a sequence of DNA) is first transcribed into mRNA. The genetic code within the mRNA is used to synthesize a protein with a particular amino acid sequence. This second process is called translation. A particular protein in a living cell influences an organism's particular trait
Briefly explain how gene expression occurs at the molecular level.
It inhibits DNA gyrase
Chemicals such as quinolones are antibacterial. How does it kill bacteria?
B DNA
DNA form is right handed and most common in living organisms
5' to 3'
DNA polymerases add new nucleotides in which direction?
greater reproductive success in their native environment
Evolutionary change caused by natural selection results in species with
An allele is an alternative version of a particular gene. Different alleles of a gene have different DNA sequences.
Explain the relationship between 'allele and gene'. Give example.
-Population level -Organism level -Molecular level -cellular level
Gene expression can be viewed at which levels?
1
How many origins of replication are there in bacteria?
Joining of Okazaki fragments
If DNA polymerase I were mutated so that all its enzymatic activities were inactive, which part of replication would be most affected
a 5' carbon in an adjacent deoxyribose
In a DNA strand, a phosphate connects a 3′ carbon atom in one deoxyribose to
be exposed to killed capsulated bacteria
In order to transform to a virulent form of bacteria, non encapsulated bacteria must
Primase
Manufactures a 10-12 base segment of RNA
-makes the chromosomal DNA more compact. -can promote DNA strand separations in small regions. -creates tension because of the under-winding of the DNA.
Negative Supercoiling in bacteria
Promotes DNA strand separation
Negative supercoiling may enhance activities like transcription and DNA replication because it
3' to 5', 5' to 3'
RNA polymerase slides along the template DNA strand in _______ direction forming an mRNA in _______ direction
DNA polymerase III
Responsible for the majority of DNA replication
...
T OR F:
False
T OR F: A nucleoside consists of only a 5 carbon sugar and a phosphate group
True
T OR F: After the action of the helicase, single-stranded binding proteins keep the parental DNA strands from reforming a double-helix
True
T OR F: Catenanes form in cells with circular chromosomes, such as bacteria
True
T OR F: Histone H1 is a linker histone
True
T OR F: In Bacterial RNA Polymerase, the Catalytic subunits are Beta and Beta'.
False
T OR F: In Griffith's experiment the mouse injected with capsulated Streptococcus pneumoniae survived, whereas the mouse injected with non-encapsulated S. pneumoniae died.
True
T OR F: In the experiment of Avery, McLeod and McCarty, the addition of DNase to the DNA extract of smooth encapsulated S. pneumoniae prevented the conversion of rough non encapsulated S. pneumoniae into the smooth encapsulated bacteria
False
T OR F: Positive Supercoiling promotes DNA strands separation
False
T OR F: The Meselson-stahl experiments used 35S radioisotopes to determine the mechanism of DNA replication
True
T OR F: The RNA polymerase connects nucleotides in a 5' to 3' direction by creating a bond between the 5' phosphate group of one nucleotide and the 3'-OH group of the second nucleotide
False
T OR F: The RNA polymerase forms a closed complex during the process of elongation during transcription
True
T OR F: The different DNA configurations that are generated by super coiling are called Topoisomers of one another
False
T OR F: The movement of the replication fork in bacterial replication is unidirectional
True
T OR F: The origin of replication in bacteria is called OriC
True
T OR F: The synthesis of the daughter strand of DNA that occurs away from the replication fork is the lagging strand
True
T OR F: a purine on one strand of the DNA is always paired with a pyrimidine on the other strand
True
T OR F: during the initiation phase of transcription the sigma factor, which is bound to RNA polymerase, binds to the major groove of DNA and recognizes sequence elements at the promoter. This process forms a closed complex
True
T OR F: in prokaryotes, transcription elongation requires the release of the sigma factor
True
T OR F: the Ability of the DNA polymerase to remove mismatched bases is called exonuclease cleavage (proofreading)
False
T OR F: the Meselson-Stahl experiments supported the model of dispersive DNA replication
False
T OR F: the Pribnow box contains a CACAAC consensus sequence located in the -100 region of the promoter
False
T OR F: the formation of open complex usually forms in GC rich regions of DNA due to the decreased number of hydrogen bonds.
True
T OR F: the majority of bacterial DNA is negatively super coiled
True
T OR F: the template strand of DNA is also called the non-coding strand and the non-templating strand of DNA is also called the coding strand
False
T or F: The DNA-protein complex in eukaryotic chromosomes is called the genome.
True
T or F: gene expression involves the process of transcription and translation
- a few hundred to several thousand different genes - multiple origins of replication - a centromere - telomeres at their ends
The chromosomes of Eukaryotes typically contain
the AT/CG rule
The complementarity of DNA strands is based on
DNA
The element that transformed the bacteria in Griffith's experiments was
antiparallel
The fact that the two strands of the DNA double helix are arranged in opposite directions gives DNA its __________ characteristics.
- an AT-rich region -GATC methylation sequences -DNAA box sequences
The origin of replication in E. coli contains
morphs
Three populations of an organism, each with drastically different external markings, but still members of the same species, would be called
True
Topoisomerase I relaxes negative supercoils in DNA
overwinding and positive supercoiling
Turning the DNA helix to the right causes
Formation of Stem Loop Structure
What do both the rho-dependent and the rho-independent mechanisms of termination have in common?
semiconservative
What is the name for the mechanism of DNA replication in which one parental strand and one daughter strand are combined following replication?
+1
What is the number denoted to the transcriptional start site which is the first base used as a template for transcription?
Transcription will continue as the mutation will prevent rho-dependent termination
What would be the consequences of a mutation removed the rut site from the RNA molecule during transcription?
telomeres
Which is found at the end of a eukaryotic chromosome?
