Nucleotide Structure

Question 1

Nucleotide =______________+______________+ ______________

Answer 1

Nucleotide = nitrogenous base + pentose sugar + phosphate

Question 2

This refers to the combination of nitrogenous base & pentose sugar

Answer 2

Nucleoside

Question 3

This serves as the bond between the 5’-OH of pentose sugar and phosphoryl group.

Answer 3

Ester bond: Phosphodiester Bond

Question 4

True or False. DNA-protein interaction is via hydrophobic interaction only.

Answer 4

False. DNA -protein interaction is via hydrophobic interaction & ionic bonding.

Question 5

This rule states that the number of purines = Number of pyrimidines.

Answer 5

Chargaff’s Rule

Question 6

Identify the most abundant chromatin protein.

Answer 6

Histones

Question 7

This type of DNA is the most common form physiologically.

Answer 7

B-DNA

Question 8

Which histone is seen in the linker region?

Answer 8

H1

Question 9

Differentiate Euchromatin versus Heterochromatin.

Answer 9

Euchromatin:
1. Less condensed
2. Transcriptionally active
3. Stains less densely

Heterochromatin:
1. Highly condensed
2. Transcriptionally inactive
2. Stains densely

Question 10

This is the most heterogenous RNA.

Answer 10

mRNA

Question 11

This is the most abundant RNA, about 80% of total RNA.

Answer 11

rRNA

Question 12

What are the unusual bases tRNA?

Answer 12

1. Dihydrouridine
2. Pseudouridine
3. Inosine
4. Ribothymidine

Question 13

What is the production of an RNA copy from a DNA strand called?

Answer 13

Transcription

Question 14

What activator is responsible for transcription which functions to add one ribonucleotide at a time to an elongating RNA strand?

Answer 14

Polymerase

Question 15

What are the types of non- protein coding RNA?

Answer 15

1. rRNA
   2.IncRNA
   3.tRNA
   4.snRNA
   5.miRNA
   6.siRNA

(MISS TR)

Question 16

Which type of non-coding RNA play a significant role in diabetes mellitus?

Answer 16

IncRNA

Question 17

Name the 3 stop codons that terminate translation

Answer 17

1. UAA
2. UGA
3. UAG

Question 18

The poisonous mushroom Amanita Phalloides (death cap) contains the peptide a-amnitin which inhibits ___________?

Answer 18

RNA Polymerase II

Question 19

Which antibiotic binds to the B subunit of bacterial DNA-dependent RNA Polymerase

Answer 19

Rifampicin

Question 20

__________ is purine to purine & pyrimidine to pyrimidine

Answer 20

Transition

Question 21

_________% of cellular DNA is in mitochondria.

Answer 21

0.01%

Question 22

Which DNA is described as left-handed helix with 12 base pairs per turn?

Answer 22

Z-DNA

Question 23

This is the adapter molecules that translate the nucleotide sequence of mRNA into specific amino acids.

Answer 23

Transfer RNA

Question 24

Which RNA is involved in rRNA and mRNA processing and gene regulation?

Answer 24

Small Nuclear RNA

Question 25

Which maintain the separation of the parent strands?

Answer 25

Single- stranded DNA binding proteins

Question 26

These are RNA molecules that have the ability to catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes.

Answer 26

Ribozymes

Question 27

True or False. G-C bonding is stronger than A-T bonding.

Answer 27

True. 3H bonds vs 2H bonds. The higher the G-C content of a DNA, the higher the melting temperature of DNA.

Question 28

DNA is wrapped _______ times over a histone octamer in left-handed helix.

Answer 28

1.75 times

Question 29

Identify the number of base pairs per turns in a Z-DNA.

Answer 29

12 base pairs

Question 30

Name the two types of grooves of the DNA.

Answer 30

Major & Minor grooves

Question 31

Levels of DNA organization that consists of nucleosomes separated by a linker DNA.

Answer 31

10nm chromatin fibril

Question 32

True or False. Nucleic acids are negatively charged at physiologic pH.

Answer 32

True

Question 33

Levels of DNA organization also known as “solenoid”.

Answer 33

30 nm chromatin fibril

Question 34

Characteristics of the genetic code where a certain codon codes, always codes for the same amino acid.

Answer 34

Non-ambiguous / Specific

Question 35

Characteristics of a genetic code where codon always code for the same **amino acid** from **generation to generation** and between species.

Answer 35

Universal

Question 36

What characteristics of a genetic code where a given amino acid may have more than one triple codon coding for it.

Answer 36

Redundant / Degenerate

Question 37

What characteristics of a genetic code where DNA is read from a starting point as a continuous sequence of bases , taken three at a time without any gaps?

Answer 37

Non-overlapping / Commaless

Question 38

What are the (7) Nitrogenous bases ?

Answer 38

Guanine Adenine Thymine Uracil Cytosine Xanthine Hypoxanthine

Question 39

Enumerate (6) Nucleosides ?

Answer 39

Guanosine Adenosine Thymidine Cytidine Uridine Inosine Nucleoside = base + Sugar

Question 40

Enumerate (4) Nucleotides?

Answer 40

ATP GMP UDO cAMP Nucleotides = base + sugar + phosphate