Module 6

Question 1

Genetic material must:

Answer 1

1. Contain information
2. Be transmissible
3. Be replicable
4. Allow for variation

Question 2

Griffith’s Experiments

Answer 2

Exposed mice to Smooth (encapsulated) and Rough strains of S. pneumoniae, discovered that inoculation with live Smooth bacteria killed mice and dead Smooth bacteria with live Rough also killed them (theory of transformation)

Question 3

Avery, MacLeod, and McCarty Experiments

Answer 3

Retried Griffith’s experiments, treated Smooth DNA with DNase and discovered there was no growth

Question 4

Nucleic Acid Structure (4 levels)

Answer 4

1. Nucleotide order
2. Linear structure
3. Double-helix
4. 3D folding

Question 5

Components of Nucleotides

Answer 5

• Phosphate group
• Pentose sugar (ribose/deoxyribose)
• Nitrogenous base (A, T, C, G, and U)

Question 6

Pyrimidines (C, T, U) have ____ carbon-nitrogen ring while purines (G, A) have ____

Answer 6

one, two

Question 7

Nucleotides are connected in a DNA strand via a ____ moving in the ____ direction

Answer 7

sugar-phosphate backbone, 5’-3’

Question 8

Pauling

Answer 8

Proposed alpha helix structure

Question 9

Franklin

Answer 9

Performed X-ray diffraction, suggested helical structure of DNA, 10 base pairs (bp) per turn, and that there was more than 1 strand

Question 10

Chargaff

Answer 10

Suggested that quantities of A and T, and C and G were similar, and that the four nucleotides were coupled

Question 11

DNA Strand Characteristics

Answer 11

• Two strands twisted together, bound by H bonds between nitrogenous bases
• Deoxyribose pentose sugar
• 10 bps per turns
• Strands run anti-parallel
• Helix is right handed
• Asymmetrical grooves (major/minor)

Question 12

RNA Strand Characteristics

Answer 12

• Single stranded
• Ribose pentose sugar
• U instead of T
• May include bulge, internal, multi-branched, and stem loops

Question 13

Bacterial Chromosome Organization

Answer 13

Single, double-stranded DNA circular chromosome residing in nucleoid structure

Question 14

Nucleoid

Answer 14

Non-membranous structure containing bacterial chromosome

Question 15

Bacterial DNA Supercoiling

Answer 15

Formation of additional coiling due to twisting, occurs in under (via DNA gyrase) and overwinding (via DNA Topoisomerase I) cases

Question 16

____ may occur due to negative supercoiling

Answer 16

Strand separation

Question 17

Eukaryote Chromosome Organization

Answer 17

One or more sets of linear chromosomes, each made up of a single DNA molecule, residing within the membrane-bound nucleus with multiple characteristic sequences

Question 18

3 types of eukaryotic DNA sequences include:

Answer 18

1. Origins of replication
2. Centromeres
3. Telomeres

Question 19

Eukaryotes have more DNA than bacteria because:

Answer 19

Of the accumulation of repetitive sequences, more complex processes

Question 20

Two ways which transposable elements can move:

Answer 20

1. Simple transposition (TE moves directly to target site)
2. Retrotransposition (TE moves via RNA intermediate)

Question 21

Simple Transposition

Answer 21

TEs flanked by inverted repeats that contain transposase and catalyze the transposition event

Question 22

Retrotransposition

Answer 22

Utilizes reverse transcriptase to encode retrotransposons into RNA and then endonuclease/integrase to be added back to DNA

Question 23

Smaller/simpler species often have ____ TEs in their genome relative to the total number of genes

Answer 23

fewer

Question 24

Nucleosome

Answer 24

Compacted DNA wrapped around octamer of histone proteins, verified by Noll by digesting DNA and identifying cuts at linker DNA portions using gel electrophoresis to establish “beads on a string” model

Question 25

30nm Fiber

Answer 25

Folds nucleosomes into loop domains using CCCTC binding factor

Question 26

Chromosome Territory

Answer 26

When chromosomes are not condensed, they tend to stay together within the nucleus regardless

Question 27

Heterochromatin

Answer 27

Tightly compacted regions, generally transcriptionally inactive, loop domains compact DNA

Question 28

Euchromatin

Answer 28

Less condensed, transcriptionally active, 30nm fibers

Question 29

Condensin

Answer 29

Multiprotein complex that works to condense chromosomes during metaphase