Lecture 3 - Introduction to Nucleic Acids Flashcards Preview

Unit 1 - Molecular and Cellular Principles of Medicine > Lecture 3 - Introduction to Nucleic Acids > Flashcards

Flashcards in Lecture 3 - Introduction to Nucleic Acids Deck (27):
1

What is the central dogma of molecular biology

DNA Replication > Transcription (to RNA) > Translation (to protein)

2

What is the general structure of a nucleic acid in DNA?

Sugar with base attached at 1' and phosphate on 5', no 2' OH

3

What is the difference between DNA and RNA?

RNA has 2' OH

4

What is the difference between a nucleotide and nucleoside?

Nucleotide has a 5' phosphate, nucleoside has 5' OH

5

What is the direction of phosphodiester bonds?

5' to 3'

6

What charge does this create for the backbone of the DNA molecule?

Negatively charged

7

What is the general structure of a pyrimidine?

6 member ring with N at 1st and 3rd carbons

8

What bases are pyrimidines?

Cytosine, thymine, and uracil

9

What is the different between thymine and uracil?

Thymine demethylated at the 5th carbon = Uracil

10

What is the general structure of a purine?

6 member ring attached to 5 member ring

11

What bases are purines?

Adenine and guanine

12

What are some functions for nucleotides?

Building blocks for nucleic acid polymers (DNA, RNA), energy carriers (ATP, GTP), coenzymes (FAD, NADP), precursors for secondary messangers (cAMP)

13

How are strands of DNA arranged?

In antiparallel strands with complementary base pairing

14

Which bases pair with which and with how many hydrogen bonds?

G-C (3 H bonds), A-T (A-U) (2 H bonds)

15

What are the structural features of B DNA?

Right handed helix, 90 degrees from bp to backbone, 1 turn of helix = 10.5 bp, 34 angstroms, major and minor grooves

16

What are the two other forms or DNA?

A DNA and Z DNA

17

Important facts about A DNA?

Right handed, 11 bp/turn, essentially shorter, squater version of B DNA

18

Important facts about Z DNA?

Left handed, 12 bp/turn, elongated

19

DNA bending facilitates what...

Protein DNA interactions!

20

What are some factors in DNA's denaturation?

Size, GC content, [salt], pH

21

How is DNA packaged into cells?

Wound around nucleosome (comprised of 8 histone proteins), fold into 30 nm fiber, form loops, and ultimately coil into chromosome.

22

What is the difference between euchromatin and heterochromatin?

Euchromatin is loosely packed (being transcribed) and heterchromatin is tightly packed.

23

What causes negative supercoiling? What about positive?

Underwound DNA = negative
Overwound DNA = positive

24

What enzymes exist to relieve supercoiling?

Topoisomerases

25

What is the difference between type 1 and type 2 topoisomerase?

Type 1: cuts one strand to relieve supercoiling

Type 2: cuts both strands

26

In what ways is RNA different than DNA?

1. Single stranded 2. Shorter in length 3. Complex tertiary structure 4. Unstable

27

What are the types of RNA?

mRNA - contains info from DNA and is template for protein synth

NON-Coding RNAs; rRNA, tRNA, miRNA, ribozymes