Lecture 2-5

Question 1

Humans have how many chromosomes?

A) 44
B) 46
C) 23 pairs
D) 22 pairs
E) 48

Answer 1

B + C

Question 2

What element is absent from DNA?

Hydrogen
Nitrogen
Sulfur
Phosphate
Oxygen

Answer 2

Sulfur

Question 3

Chromatin is comprised of what ?

Answer 3

DNA and Protein

Question 4

Condensed regions of DNA are:

A) Called euchromatin
B) Rich in AT
C) Rich in GC
D) Called heterochromatin

Answer 4

Called Heterochromatin and rich in AT

Question 5

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

Answer 5

D

Question 6

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

Answer 6

E

Question 7

TRUE OR FALSE

The number of chromosomes correlates with the complexity of the organism?

Answer 7

False

Question 8

TRUE OR FALSE

The BCR-Abl fusion protein arises from a chromosomal translocation?

Answer 8

True

Question 9

TRUE OR FALSE

Sickle-cell disease arises from a single nucleotide change in the alpha-globin gene ?

Answer 9

False

It arises from an A Bevin changed to a T in position 17 of the gene for the beta chain of haemoglobin

Question 10

TRUE OR FALSE

In the Avery experiments, DNAase treatment of heat killed smooth strain material resulted in transformation of rough stain

Answer 10

False

Question 11

TRUE OR FALSE

Nondisjunction results in abnormal chromosome numbers in daughter cells following cell division?

Answer 11

True

Question 12

TRUE OR FALSE

Mutations in the CFTR gene directly affect calcium balance in the airway epithelium

Answer 12

False

Question 13

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

Answer 13

B + D

Question 14

TRUE OR FALSE

In the Hershey-Chase experiment, centrifugation is used to pellet and purify the bacteriophage coats

Answer 14

False

Question 15

Which purine base is contained within DNA?

Answer 15

Adenine

Question 16

The primary alcohol is on what carbon of deoxyribose?

Answer 16

5

Question 17

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

Answer 17

A + B + E

Question 18

What wavelength of light is used to determine DNA melting temperature?

Answer 18

260nm

Question 19

Does single stranded DNA exhibit hypochromisity or hyperchromisity at 260nm ?

Answer 19

Hyperchromisity

Question 20

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

Answer 20

C

Question 21

If you are given the sequence 5’- GCATGGCA, what is the complementary 5’ - 3’ sequence:

Answer 21

TGCCATGC

Question 22

TRUE OR FALSE

B- DNA is a left handed helix ?

Answer 22

False,
It is a right-handed helix

Question 23

Which histone does not make up the core histone octamer?

Answer 23

H1

Question 24

TRUE OR FALSE

Histone are rich in acidic amino acids?

Answer 24

False

Question 25

TRUE OR FALSE The major and minor grooves of DNA result from the asymmetrical orientation of the glycosidic bonds

Answer 25

True

Question 26

Is Z-DNA left handed or right handed?

Answer 26

Left handed

Question 27

How many hydrogen bonds does A-T nucleotide have in DNA?

Answer 27

2 hydrogen bonds

Question 28

TRUE OR FALSE GC-rich DNA will have a lower melting temperature

Answer 28

False This is because G-C baes have 3 hydrogen bonds between them therefore require more energy to overcome

Question 29

TRUE OR FALSE B-DNA is the dehydrated form of DNA

Answer 29

False

Question 30

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

Answer 30

D

Question 31

TRUE OR FALSE In Cesium chloride density gradient centrifugation, DNA separates according to its mass

Answer 31

False

Question 32

TRUE OR FALSE DNA replication in E. coli occurs at multiple sites in the genome

Answer 32

False

Question 33

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

Answer 33

B

Question 34

TRUE OR FALSE The lagging strand synthesis is due to DNA polymerase only functioning in 5' to 3' direction

Answer 34

True

Question 35

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

Answer 35

False

Question 36

TRUE OR FALSE During lagging strand synthesis, the short fragments are joined together to form a glycosidic bond

Answer 36

False

Question 37

TRUE OR FALSE To perform Sanger sequencing, an equal concentration of ddNTP is added to the dNTPs in the reaction

Answer 37

False

Question 38

TRUE OR FALSE A DNA-directed RNA primase is required for DNA polymerase to initiate DNA strand extension

Answer 38

True

Question 39

TRUE OR FALSE On an agarose gel, DNA migrates towards the positively charged electrode

Answer 39

True

Question 40

TRUE OR FALSE Next generation sequencing uses a 'reversible terminator' that has a blocking group on the 2' carbon of deoxyribose

Answer 40

False It is bond to the 3’ carbon of the deoxyribose

Question 41

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

Answer 41

True

Question 42

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

Answer 42

B

Question 43

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

Answer 43

B + D

Question 44

DNA ligase requires _____ to join DNA fragments

Answer 44

ATP

Question 45

With respect to RNA, what carbon on the ribose sugar has an additional -OH group compared to DNA?

Answer 45

2

Question 46

TRUE OR FALSE tRNAs provide a template for protein synthesis

Answer 46

False

Question 47

TRUE OR FALSE RNA polymerase requires a primer to initiate RNA synthesis

Answer 47

True (Unlike DNA polymerase, RNA polymerase doesn’t require a primer)

Question 48

TRUE OR FALSE The operon system in prokaryotes is an example of a polycistronic mRNA

Answer 48

False

Question 49

What subunit stabilises the assembled E.coli RNA polymerase? A) Alpha B) Beta C) Beta’ D) Omega E) Sigma

Answer 49

D

Question 50

What subunit directs the E.coli RNA polymerase to the correct transcription initiation sites? A) Alpha B) Beta C) Beta’ D) Omega E) Sigma

Answer 50

E

Question 51

TRUE OR FALSE The transcription termination signals are contained in the DNA template

Answer 51

False Signals for termination are in the newly synthesised RNA

Question 52

TRUE OR FALSE The poly A tail modification of mRNAs is required for translation initiation

Answer 52

False poly A tail increases stability and assists in nuclear export

Question 53

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

Answer 53

D

Question 54

TRUE OR FALSE The spliceosome is comprised of protein and rRNA.

Answer 54

False

Question 55

When lactose is present, the repressor protein of the lac operon is A) active B) inactive

Answer 55

B

Question 56

When tryptophan is present, the trp operon is turned A) off B) on

Answer 56

A

Question 57

TRUE OR FALSE In eukaryotes, basal transcription factors are specific to a limited set of genes

Answer 57

False

Question 58

TRUE OR FALSE miRNAs act to promote translation of particular mRNAs

Answer 58

False ( miRNAs destabilise mRNAs - either leading to their degradation or blocking translation. Aim to block protein production )

Question 59

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

Answer 59

B + D + E