Unit 1: DNA & The Genome - Key Area 1: Structure of DNA

Question 1

define ‘genome’

Answer 1

an organisms complete set of DNA including all of its genes

Question 2

what is a function of DNA?

Answer 2

stores genetic information in a sequence of bases which determines an organisms genotype and structure of proteins

Question 3

what does the base sequence of DNA form?

Answer 3

genetic code

Question 4

name the repeating units that make up a molecule of DNA

Answer 4

nucleotides

Question 5

what are the components of a nucleotide

Answer 5

phosphate, deoxyribose sugar and base

Question 6

what bonds different nucleotides together in a strand and describe them?

Answer 6

strong chemical bonds. Forms between the phosphate group of one nucleotide and carbon 3 of a sugar on another

Question 7

what type of bonds are between bases

Answer 7

weak hydrogen bonds

Question 8

what shape does DNA form?

Answer 8

a double helix

Question 9

why are DNA strands described to be anti-parallel?

Answer 9

because they run in opposite directions making them antiparallel, the left strands runs from 5’ end to 3’ end while the right strand runs from 3’ to 5’ end.

Question 10

what end does the deoxyribose sugar occur?

Answer 10

3’ end

Question 11

what end does the phosphate occur?

Answer 11

5’ end

Question 12

describe the base pairing rule

Answer 12

Adenine to Thymine

Cytosine to Guanine

Question 13

what are the types of eukaryotes?

Answer 13

plant, fungal and animal cells

Question 14

what is a special eukaryote that contains plasmids?

Answer 14

yeast cell

Question 15

what is a sugar-phosphate backbone?

Answer 15

strongly bonded strand of DNA

Question 16

what does prokaryotic refer to?

Answer 16

refers to the domain of life characterised by cells with no discrete nucleus

Question 17

what does eukaryotic refer to?

Answer 17

refers to a domain of life characterised by cells with a discrete nucleus

Question 18

Cell organelles in which the aerobic stages of respiration occur

Answer 18

mitochondria

Question 19

Organelle in which the chemical reactions of photosynthesis occur

Answer 19

chloroplast

Question 20

Structure that contains the genetic material of an organism encoded into DNA

Answer 20

chromosome

Question 21

define ‘plasmid’

Answer 21

a small circular piece of DNA

Question 22

organisms which lack a membrane bound nucleus

Answer 22

prokaryotes

Question 23

what are the type of prokaryotes?

Answer 23

bacteria cell

Question 24

where is DNA found in prokaryotes?

Answer 24

in the cytoplasm of the cell

Question 25

organisms which have a membrane bound nucleus that stores genetic material

Answer 25

eukaryotes

Question 26

what is the name of the protein packaged in linear chromosomes?

Answer 26

histone

Question 27

describe the structure of a prokaryote cell

Answer 27

> prokaryote cells have circular chromosomal DNA which is contained in the cytoplasm as plasmids
don’t have a nucleus
there is no DNA in organelles as prokaryote cells like bacteria don’t have any organelles.

Question 28

describe the structure of a eukaryote cell

Answer 28

> eukaryote cells have a nucleus present
linear chromosomes that are tightly coiled and packaged with the protein histone is contained in the nucleus
there are only plasmids present in some yeast cells but absent in plant and animal cells
there is circular chromosomes found in mitochondria
there is circular chromosomes found in chloroplasts