Introduction to biomolecules

Question 1

What is the general formula of a monosaccharide?

Answer 1

(CH2O)n or CnH2nOn

Question 2

What type are the majority of the monosaccharides found in the human body?

Answer 2

D-type

Question 3

Which carbohydrate is present in DNA?

Answer 3

Deoxyribose

Question 4

D-glucose and L-glucose are not?

Answer 4

Anomers

Question 5

The most common site of phosphorylation of nucleotides found in cells is the hydroxyl group attached to which carbon?

Answer 5

Carbon 5’

Question 6

What are adjacent nucleotides joined by in nucleic acids?

Answer 6

Phosphodiester bond

Question 7

What functions does cholesterol have?

Answer 7

Roles in membrane structure
Adds rigidity to liquid-crystalline phospholipid bilayers
Precursor for the synthesis of the steroid hormones
Precursor for the synthesis of vitamin D

Question 8

What is the mode of DNA replication?

Answer 8

Semiconservative and bidirectional

Question 9

The synthesis of DNA in lagging strands takes place in short segments, what are these called?

Answer 9

Okazaki fragments

Question 10

Unwinding of the double helix of DNA during replication is done by what enzyme?

Answer 10

DNA helicase

Question 11

What reaction is required for proofreading during DNA replication by DNA polymerase III?

Answer 11

3’-5’ exonuclease activity

Question 12

Are nucleotides added on to the 5’ end of the growing DNA strand in DNA replication?

Answer 12

No

Question 13

What is the name of the enzyme that fills in the gap between fragments in the lagging strands?

Answer 13

DNA polymerase I

Question 14

Which enzyme is used to join the DNA fragments of the lagging strand

Answer 14

DNA ligase

Question 15

Which reaction in DNA replication is catalysed by DNA ligase?

Answer 15

Formation of phosphodiester bond between the 3’ OH of one Okazaki fragment and the 5’ phosphate of the next on the lagging strand

Question 16

In which would you find telomeres?

Answer 16

Human chromosomes - repetitive DNA sequences on the end of human chromosomes

Question 17

Do telomeres become longer or shorter as they age?

Answer 17

Shorter

Question 18

Do somatic cells have little or lots of telomerase?

Answer 18

Little

Question 19

Do immortal cancer cell lines have high levels of telomerase?

Answer 19

Yes

Question 20

What is the enzyme that elongates chromosomes by adding repeated sequences to the end of existing chromosomes during replication in eukaryotes?

Answer 20

Telomerase

Question 21

What describes the Pribnow box?

Answer 21

The -10 box

Question 22

What is the region of DNA that leads to initiation of transcription?

Answer 22

Promoter

Question 23

What is the role of the sigma factor in bacterial RNA polymerase?

Answer 23

To position RNA polymerase correctly on the DNA template

Question 24

In eukaryotes the assembly of transcription factors on a promoter begins some 25 nucleotides upstream where it binds to start a … sequence?

Answer 24

TATA

Question 25

Which is described as a sequence that can be several thousand base pairs upstream or downstream of a eukaryotic promoter and which increases gene expression as much as 200-fold?

Answer 25

Enhancer

Question 26

What is the role of methylation of DNA?

Answer 26

To insure that genes that are turned off, stay off

Question 27

What direction is RNA synthesis?

Answer 27

5' to 3'

Question 28

What is the cap modification of eukaryotic mRNA?

Answer 28

A modified guanine nucleotide added to the 5' end of the transcript

Question 29

At which cell cycle checkpoint is the cell cycle halted if the cells DNA is damaged?

Answer 29

G1 - S

Question 30

Termination causes a stem-loop structure forming in the RNA transcript - is this true

Answer 30

Yes

Question 31

What is the role of eukaryotic RNA polymerase I?

Answer 31

Transcription of the major RNA transcript