Nucleic Acids and the RNA World Flashcards Preview

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Flashcards in Nucleic Acids and the RNA World Deck (33):
1

If you have a polymer with 10 A bases followed by 10 C bases and the strand bonds to another strand with 20 T bases, how would the stand be different than normal?

The width of the DNA double helix would vary along the length of the strand

2

Which carbon does the phosphate group bond to on the sugar?

5

3

Which carbon does the nitrogenous base bond to on the sugar?

1

4

Why does G not pair with T and A pair with C?

They cannot form as many hydrogen bonds as A-T and G-C pairs

5

What is the structural feature that allows DNA to replicate?

Complimentary pairing between the nitrogeneous bases

6

RNA world hypothesis

RNA both stored genetic information and catalyzed its own replication

7

3 components of a nucleotide

1. phosphate group
2. 5 carbon sugar
3. nitrogenous base

8

What is the central component of the nucleotide?

sugar

9

Difference between ribose and deoxyribose

Deoxyribose contains one less oxygen on its 2 position of the sugar

this hydroxide on the 2 of ribose makes it much more reactive and less stable

10

Purines

adenine and guanine

both contain 9 rings (larger)

11

Pyrimindines

cytosine, uracil, thymine

contain 6 rings

12

How do nucleotides polymerize?

Via condensation

reactions between hydroxyl on the sugar of one nucleotide and phosphate on another nucleotide

13

What does the condensation reaction create?

Phosphodiester linkage (covalent)

H20 is released

14

5' end

contains an unlinked 5' phosphate

15

3' end

contains an unlinked 3' hydroxyl (sugar)

16

Which end are nucleotides added to in growing chain?

3' end

this makes sense because the 3' end contains the central sugar from which things are attatched

17

Why is polymerization not spontaneous?

It requires an input of energy

18

How is polymerization catalyzed?

the creation of activated nucleotides (ATP)

3 phosphates are all negatively charge and thus they have a strong repel force

19

What is the backbone of nucleic acids?

Sugar-phosphate backbone

20

What did Franklin and Wilkins tell us?

showed that the pattern of the molecule was probably helical

21

Chargaff's rule

the number of purines in a given molecule is equal to the number of pyrimidines

22

What type of bonds form between nitrogenous bases?

Hydrogen

23

Antiparallel

two strands of DNA must be oriented in opposite directions

24

What do the negatively charged phosphates make DNA?

Hydrophillic overall

25

DNA grooves

allow proteins to bind

26

What makes DNA twist?

hydrophobic interactions

vander der Waals interactions

27

Tertiary structure of DNA

normally wraps around proteins called histones

28

DNA copying steps

**NEED TO LEARN**

29

paradox of DNA

its orderliness and stability makes it great at storing information but also make it a bad catalysis

therefore, RNA is preferred to be the first self-replicating molecule

30

How is secondary structure of RNA different?

It folds with the same strand

it does not have a complementary strand

31

Hairpin

this occurs in the loop of RNA where there are unpaired bases because of the single strand secondary structure of Rna

32

RNA's versatility

RNA can fold into many 3D shapes, which makes it more versatile than DNA

33

Ribozymes

RNA enzymes that help catalyze reactions

similar to protein enzymes