KH1

Question 1

What are these: DNA, RNA, proteins?

Answer 1

Informational biopolymers

Question 2

What’s a polymer?

Answer 2

A covalently linked monomer chain

Question 3

How is information contained in DNA, RNA and proteins?

Answer 3

Through the sequence/order of their monomers

Question 4

What’s the generic structure of Informational biopolymers?

Answer 4

A COMMON ELEMENT which forms the “backbone” and CHARACTERISTIC ELEMENTS creating “side-chains” that protrude/stick out.

Question 5

True or False? “Monomer chemistry dictates polymer structure”

Answer 5

True

Question 6

Are informational biopolymers branched or linear?

Answer 6

Linear

Question 7

How is it scientifically better for informational biopolymers to be linear?

Answer 7

It makes it easier to determine the structures.

Question 8

True or False? “Informational biopolymers always have two separate ends (i.e. they never join).”

Answer 8

False. They can join and create a circular molecule (ex: DNA molecules of bacteria and some viruses)

Question 9

What do we mean by “asymmetric monomers” when describing informational biopolymers?

Answer 9

The two joining sites are different.

Question 10

What’s are consequences of monomer asymmetry?

Answer 10

Polymer asymmetry (two different ends) and unidirectional growth.

Question 11

How to draw a polymer by convention?

Answer 11

The chain growth occurs towards the right.

Question 12

What are the monomers of DNA? RNA? Proteins?

Answer 12

Nucleotides, nucleotides and amino acids.

Question 13

What’s the generic structure of a nucleotide?

Answer 13

Contains a HETEROCYCLIC BASE as its characteristic element (T, U, A, C, G) and PENTOSE SUGAR PHOSPHATES create its backbone.

Question 14

What are the two joining sites of a nucleotide?

Answer 14

The 5’ PHOSPHATE and the 3’ OH (hydroxyl).

Question 15

From where do nucleotide chains grow?

Answer 15

3’ end.

Question 16

What’s the difference between DNA and RNA nucleotides?

Answer 16

DNA : deoxyribose nucleotides (missing the 2’ OH)
RNA : ribose nucleotides

Question 17

What’s an advantage of deoxyribose monomers compared to ribose ones?

Answer 17

More stability thanks to more resistance to chain cleavage by hydrolysis.

Question 18

Name all bases found in RNA and DNA. Is there a difference between the two?

Answer 18

Adenine, Guanine, Cytosine : found in both // Uracil: RNA only // Thymine: DNA only

Question 19

What’s an advantage of replacing uracil with thymine?

Answer 19

Makes some chemical damage easier to repair.

Question 20

What’s the specific name of covalent bonds between nucleotides?

Answer 20

Phosphodiester bonds. (Phosphate bonded through ester linkage on both sides)

Question 21

What are the monomers of proteins?

Answer 21

Amino acids.

Question 22

What’s the generic structure of amino acids?

Answer 22

They have SIDE CHAINS (R groups) as their characteristic elements and their backbone is made of an ALPHA CARBON, a COOH and a NH2.

Question 23

True or False? “Both stereoisomers of amino acids are used to synthesize proteins.”

Answer 23

False, L only.

Question 24

What are the two joining sites of amino acids?

Answer 24

The amino group and the carboxyl group.

Question 25

From where do amino acid chains grow?

Answer 25

The carboxyl end.

Question 26

How many different amino acids are there? What’s their 3 main classes?

Answer 26

20 total. Hydrophobic (8), hydrophilic (9) and Special (3).

Question 27

What’s the specific name of covalent bonds between amino acids?

Answer 27

Peptide Bonds.

Question 28

True or False? “Monomers are directly incorporated into the chain’s growth.”

Answer 28

False. They’re energized first: NTPs or amino acyl-tRNA.

Question 29

What does “NTP” stand for?

Answer 29

“Nucleoside Triphosphate”

Question 30

Name a difference between the incorporation of NTPs and energized amino acids.

Answer 30

The NTPs lose two PO groups when joining chain. Amino acyl-tRNA lose the tRNA only when the next monomer joins.

Question 31

True or False? “Energized monomers can join chains by themselves”

Answer 31

False. Need enzymes and a template biopolymer to guide it.

Question 32

What are the enzymes used for DNA growth? RNA growth? Protein growth?

Answer 32

DNA polymerase, RNA polymerase and ribosomes.

Question 33

What are the templates for DNA growth, RNA growth and protein growth?

Answer 33

DNA, DNA and mRNA.

Question 34

True or False? “All informational biopolymers exist as single stranded chains”

Answer 34

False. Only RNA and most proteins.

Question 35

Describe the shape of a DNA molecule.

Answer 35

Double-stranded right-handed helix with antiparallel strands.

Question 36

What gives DNA its double helix shape?

Answer 36

Mainly hydrogen bonds specifically called Watson-Crick base pairs.

Question 37

True or False? “DNA has to be opened to access its information”

Answer 37

False. DNA-binding proteins can make contact with the base-pairs at either grooves (major or minor).

Question 38

How is DNA denatured? Can it be reformed? Can it bend?

Answer 38

By losing its base pairs, the strands separate but they can accurately bind back (“RENATURATION”). Yes, it can bend.

Question 39

What’s the “Tm”

Answer 39

Temperature at which DNA is half-melted.

Question 40

True or False? “The Tm of a DNA molecules depends on its base composition”

Answer 40

True. G-C pairs increase the Tm since they have an extra H-bond. It takes more energy to break them.