Chapter 6: DNA and Biotechnology

Question 1

Nucleoside

Answer 1

• made of five carbon sugar
• covalently linking the base to C-1’ of the sugar

Question 2

Nucleotides

Answer 2

• formed when one or more phosphate groups are attached to the C-5’ carbon of nucleoside

Question 3

Purines

Answer 3

adenine and guanine

Question 4

pyrimidies

Answer 4

cystosine and thymine (DNA

Cystoine and uracil (RNA)

Question 5

Huckle’s Rule

Answer 5

4n + 2

Question 6

Chargaff’s Rule

Answer 6

will have an equal amount of the complementary nucleotide base pair

(i.e. 3-A will have 3-T)

Question 7

Complemetary Base Paring

Answer 7

A is always paired to T (2 hydrogen bonds)

G is always paired to C (3 hydrogen bonds)

Question 8

B-DNA

Answer 8

• runs anti parallel to each other
• is right handed
• each turn is about 3.4 nm and contains 10 bases

Question 9

Z-DNA

Answer 9

• takes on a zig-zag appearance
• every turn contains about 4.6 nm and cointains about 12 base pairs per turn

Question 10

Probe DNA

Answer 10

• Used in polymerase chain reaction (PCR)
• a known snip of DNA is used to bind to a specific region in the DNA to identify a specific gene

Question 11

Nucleosome

Answer 11

• These are made up of DNA winding around a histone which in turn will make chromatin
• H2A, H2B, H3, and H4 make up the histone complex
  *

Question 12

H1

Answer 12

Is the last histone that is added to the complex which seals off the DNA as it enters and leves the nucleosome

adds stability to the structure

Question 13

Heterochromatin

Answer 13

• appears dark under a light microspe and is transcriptionally silent

Question 14

Euchromatin

Answer 14

• Light under the light microscopy and is loose
• contains active DNA

Question 15

Telomere

Answer 15

• added to the end of the chromosome to solve the problem and prevent genetic loss
• TTAGGG unit is added to the end of DNA

Question 16

Telomerase

Answer 16

is the enzyme that replaces any lost sequence from DNA

Question 17

Centromere

Answer 17

• Centromere are found in the center of chromosomes
• contain a high concentration of CG pyrimidienes
• allows two sister chromatid to remain attached during cell division

Question 18

Helicase

Answer 18

unwinds DNA molecule which allows two stranded template ahead of the polymerase

Question 19

single-stranded DNA binding-protein

Answer 19

• this prevents the broken DNA (by helicase) from creating hydrogen bonds
• also prevents degradation of DNA by nucleases

Question 20

DNA Topoisomerase

Answer 20

• DNA will begin to experience positive supercoiling which will cause torsional stress
• topoisomerase works ahead of the helicase and helps releave some of the stress created

Question 21

DNA polymerase

Answer 21

• synthesizes new daughter cell reading from the 3’ to 5’ direction and syntehsizing from 5’ to 3’

Question 22

Primase

Answer 22

Since DNA cannot read DNA from the begining (De novo) primase synthesizes a small 10 base pair primer