Lecture 2-5 Flashcards
Humans have how many chromosomes?
A) 44
B) 46
C) 23 pairs
D) 22 pairs
E) 48
B + C
What element is absent from DNA?
Hydrogen
Nitrogen
Sulfur
Phosphate
Oxygen
Sulfur
Chromatin is comprised of what ?
DNA and Protein
Condensed regions of DNA are:
A) Called euchromatin
B) Rich in AT
C) Rich in GC
D) Called heterochromatin
Called Heterochromatin and rich in AT
Using streptococcus, Griffith and colleagues proved that
A) DNA is the genetic material
B) DNA is the transforming material
C) Proteins are not the genetic material
D) Bacteria can transfer genetic material
D
In the Hershey-Chase experiment, the bacteriophage coat is labelled with:
A) 32-P
B) 32-S
C) 31-P
D) 34-P
E) 35-P
E
TRUE OR FALSE
The number of chromosomes correlates with the complexity of the organism?
False
TRUE OR FALSE
The BCR-Abl fusion protein arises from a chromosomal translocation?
True
TRUE OR FALSE
Sickle-cell disease arises from a single nucleotide change in the alpha-globin gene ?
False
It arises from an A Bevin changed to a T in position 17 of the gene for the beta chain of haemoglobin
TRUE OR FALSE
In the Avery experiments, DNAase treatment of heat killed smooth strain material resulted in transformation of rough stain
False
TRUE OR FALSE
Nondisjunction results in abnormal chromosome numbers in daughter cells following cell division?
True
TRUE OR FALSE
Mutations in the CFTR gene directly affect calcium balance in the airway epithelium
False
The smooth strain of Streptococcus is deadly to mice due to:
A) The pressente of a protein coat
B) An ability to evade the host immune system
C) An ability to be recognised by the host immune system
D) The presence of a polysaccharide coat
E) The a sense of a polysaccharide coat
B + D
TRUE OR FALSE
In the Hershey-Chase experiment, centrifugation is used to pellet and purify the bacteriophage coats
False
Which purine base is contained within DNA?
Adenine
The primary alcohol is on what carbon of deoxyribose?
5
Rosalind Franklin and Maurice Wilkins provided x-ray diffraction data that determined what properties of DNA?
A) Double Helix
B) Phosphates on the outside
C) Semi-conservative model of replication
D) A-T base pairing
E) 3.4 Angstrom distance between nucleotides
A + B + E
What wavelength of light is used to determine DNA melting temperature?
260nm
Does single stranded DNA exhibit hypochromisity or hyperchromisity at 260nm ?
Hyperchromisity
What effect does high salt concentration have on DNA melting?
A) Decreases melting temperature by neutralising negatively charged phosphate backbone
B) Increases melting temperature by interacting with nitrogenous bases
C) Increases melting temperature by neutralising negatively charged phosphate backbone
D) Decreases melting temperature by interacting with nitrogenous bases
E) Increases melting temperature by neutralising positively charged phosphate backbone
C
If you are given the sequence 5’- GCATGGCA, what is the complementary 5’ - 3’ sequence:
TGCCATGC
TRUE OR FALSE
B- DNA is a left handed helix ?
False,
It is a right-handed helix
Which histone does not make up the core histone octamer?
H1
TRUE OR FALSE
Histone are rich in acidic amino acids?
False
TRUE OR FALSE
The major and minor grooves of DNA result from the asymmetrical orientation of the glycosidic bonds
True
Is Z-DNA left handed or right handed?
Left handed
How many hydrogen bonds does A-T nucleotide have in DNA?
2 hydrogen bonds
TRUE OR FALSE
GC-rich DNA will have a lower melting temperature
False
This is because G-C baes have 3 hydrogen bonds between them therefore require more energy to overcome
TRUE OR FALSE
B-DNA is the dehydrated form of DNA
False
According to the Meselson & Stahl experiment, what is expected after the 3rd generation?
A) 50% has density of 14N, 50% has intermediate density
B) 50% has density of 14N, 50% has density of 15N
C) 75% has inter,deviate density, 25% has density of 14N
D) 75% has density of 14N, 25% has intermediate density
E) 100% has intermediate density
D
TRUE OR FALSE
In Cesium chloride density gradient centrifugation, DNA separates according to its mass
False
TRUE OR FALSE
DNA replication in E. coli occurs at multiple sites in the genome
False
If the conservative model of replication would have been proven by Meselson and Stahl, what would you have expected at the 1st generation?
A) 100% at the intermediate density
B) 50% at the 14N density, 50% at the 15N density
C) 25% at the 15N density, 75% at the 14N density
D) 75% at the 15N density, 25% at the 14N density
B
TRUE OR FALSE
The lagging strand synthesis is due to DNA polymerase only functioning in 5’ to 3’ direction
True
TRUE OR FALSE
To add a nucleotide to the growing end of a DNA strand, the 3’ OH group attacks the gamma phosphate of the incoming dNTP
False
TRUE OR FALSE
During lagging strand synthesis, the short fragments are joined together to form a glycosidic bond
False
TRUE OR FALSE
To perform Sanger sequencing, an equal concentration of ddNTP is added to the dNTPs in the reaction
False
TRUE OR FALSE
A DNA-directed RNA primase is required for DNA polymerase to initiate DNA strand extension
True
TRUE OR FALSE
On an agarose gel, DNA migrates towards the positively charged electrode
True
TRUE OR FALSE
Next generation sequencing uses a ‘reversible terminator’ that has a blocking group on the 2’ carbon of deoxyribose
False
It is bond to the 3’ carbon of the deoxyribose
TRUE OR FALSE
During PCR, in order for the short primer to anneal to the template strand, the temperature must be lower than the melting temperature
True
What is the primary reason for the use of a DNA polymerase, such as Taq, for PCR?
A) Due to its proof-reading activity
B) Due to its ability to withstand high DNA denaturing temperatures
C) Due to its ability to produce a daughter strand quickly
D) Due to its ability to synthesise DNA in the 5’ to 3’ direction
B
What is required for next generation (parallel) sequencing ?
A) Agarose gel separation of DNA
B) PCR (Polymerase Chain Reaction)
C) Dideoxynucleotides
D) Nucleotides with a 3’ reversible blocking group
E) Nucleotides with a 5’ reversible blocking group
B + D
DNA ligase requires _____ to join DNA fragments
ATP
With respect to RNA, what carbon on the ribose sugar has an additional -OH group compared to DNA?
2
TRUE OR FALSE
tRNAs provide a template for protein synthesis
False
TRUE OR FALSE
RNA polymerase requires a primer to initiate RNA synthesis
True
(Unlike DNA polymerase, RNA polymerase doesn’t require a primer)
TRUE OR FALSE
The operon system in prokaryotes is an example of a polycistronic mRNA
False
What subunit stabilises the assembled E.coli RNA polymerase?
A) Alpha
B) Beta
C) Beta’
D) Omega
E) Sigma
D
What subunit directs the E.coli RNA polymerase to the correct transcription initiation sites?
A) Alpha
B) Beta
C) Beta’
D) Omega
E) Sigma
E
TRUE OR FALSE
The transcription termination signals are contained in the DNA template
False
Signals for termination are in the newly synthesised RNA
TRUE OR FALSE
The poly A tail modification of mRNAs is required for translation initiation
False
poly A tail increases stability and assists in nuclear export
The 5’ cap added to mRNAs in eukaryotes contains
A) 7-methyl-adenosine
B) 3-methyl-adenosine
C) 7-methyl-cytidine
D) 7-methyl-guanosine
E) 3-methyl-guanosine
D
TRUE OR FALSE
The spliceosome is comprised of protein and rRNA.
False
When lactose is present, the repressor protein of the lac operon is
A) active
B) inactive
B
When tryptophan is present, the trp operon is turned
A) off
B) on
A
TRUE OR FALSE
In eukaryotes, basal transcription factors are specific to a limited set of genes
False
TRUE OR FALSE
miRNAs act to promote translation of particular mRNAs
False
( miRNAs destabilise mRNAs - either leading to their degradation or blocking translation. Aim to block protein production )
Introns:
A) contain AG at 5’ region that is recognised by the spliceosome
B) are spliced from the mRNA
C) contain coding regions
D) contain non-coding regions
E) contain GU at 5’ region that is recognised by the spliceosome
B + D + E
