UNIT 1: Key Area 1 a) structure of DNA

Question 1

what does DNA stand for ?

Answer 1

Deoxyribonucleic acid

Question 2

two strands of dna run in opposite directions to eachother ?
what is this called ?

Answer 2

antiparallel strands

Question 3

what are two strands of DNA joined together by ?
why are they weak ?

Answer 3

• joined by hydrogen bonds
• they are weak in order to be separated for DNA replication or protein synthesis

Question 4

what is the chemical bond between phosphate of one nucleotide and sugar on another nucleotide called ?

Answer 4

sugar-phosphate backbone
creates a permanent strand of nucleotides

Question 5

what is a nucleotide made up of ?

Answer 5

• phosphate
• base
• deoxyribose sugar

Question 6

name the DNA pairings ?

Answer 6

adenine-thymine
cytosine-guanine

Question 7

what is the shape of DNA ?

Answer 7

double helix

Question 8

wher where are nucleotides able to join?

Answer 8

3’ end of the strand

Question 9

define anti parallel strands

Answer 9

two strands of DNA
that run in opposite directions of each over

Question 10

where is DNA present

Answer 10

in all living cells

Question 11

how many strands are DNA molecules made of

Answer 11

2

Question 12

where is chloroplast DNA found

Answer 12

plants

Question 13

what are associated proteins called

Answer 13

histones

Question 14

why are hydrogen bonds weak or strong and why ?

Answer 14

• weak in order for two strands to separate

Question 15

what end is the deoxyribose ?

Answer 15

3’ end

Question 16

what end is phosphate?

Answer 16

5’ end

Question 17

where is mitochondrial DNA found

Answer 17

in plant and animals in the mitochondria

Question 18

what are DNA molecules made up of ?

Answer 18

two repeating strands of nucleotides

Question 19

define nucleotide

Answer 19

repeating units of a DNA strand

Question 20

DNA nucleotides contain __________ joined to phosphate

Answer 20

deoxyribose sugar