UNIT 2 | DNA

Question 1

What are the 3 main components of DNA nucleotides?

Answer 1

Sides:
  1. Sugar (deoxyribose)
  2. Phosphate
Rungs:
  3. Base (nitrogenous)

Question 2

Pair the correct pyrimidines and purines of DNA:
Adenine, Guanine - purines
Thymine, Cytosine - pyrimidines

Answer 2

Adenine - Thymine

Guanine - Cytosine

Question 3

Define purine

Answer 3

Two carbon rings

Question 4

Define pyrimidine

Answer 4

One carbon ring

Question 5

Helicase

Answer 5

Unwinds and unzips by breaking hydrogen bonds between bases

Question 6

DNA polymerase

Answer 6

Builds a new DNA strand by reading the parent strand and matching the nucleotides

Question 7

Primase

Answer 7

Initializes the entire process and sets a path for DNA polymerase to follow

Question 8

Ligase

Answer 8

Glues Okazaki fragments on the lagging strand of DNA (5’ - 3’)

Question 9

How many bonds exist between Guanine and Cytosine?

Answer 9

Three hydrogen bonds

Question 10

How many bonds exist between Adenine and Thymine?

Answer 10

Two hydrogen bonds

Question 11

Okazaki fragments

Answer 11

Short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication

Question 12

Which way is DNA replicated?

Answer 12

3’ to 5’ (leading strand)

Question 13

Compare and Contrast:

DNA and RNA

Answer 13

• DNA is double stranded while RNA exists in single strands
• DNA contains the sugar deoxyribose in its backbone, whereas RNA contains ribose, which has one more oxygen atom
• Both nucleic acids contain three bases: adenine, guanine and cytosine. However, RNA contains uracil as its fourth base, while DNA contains thymine.

Question 14

What are the 3 main components of RNA nucleotides?

Answer 14

1. Sugar (ribose)
2. Phosphate
3. Bases (nitrogenous)

Question 15

Pair the correct pyrimidines and purines of RNA:
Adenine, Guanine - purines
Uracil, Cytosine - pyrimidines

Answer 15

Adenine - Uracil

Guanine - Cytosine

Question 16

Codon

Answer 16

A sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule

Question 17

Anticodon

Answer 17

A sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA

Question 18

How many amino acids are there?

Answer 18

20 amino acids

Question 19

Define tripeptide

Answer 19

A peptide with three amino acids joined by peptide bonds

Question 20

Define mutation

Answer 20

The change in genetic material of a cell

Question 21

What are the two types of mutations?

Answer 21

1. Gene mutation - produce changes in a single gene

2. Chromosomal mutation - changes the whole chromosome

Question 22

Substitution (gene mutation)

Answer 22

A single nucleotide is replaced. There may be a change in amino acids

Question 23

Insertion (gene mutation)

Answer 23

A single nucleotide is inserted into the DNA sequence. A frameshift occurs and all amino acids after the mutation may be changed

Question 24

Deletion (gene mutation)

Answer 24

Similar to insertion, it can change all amino acids after the mutation occurs

Question 25

Define point mutations

Answer 25

Occurs at a single point in the sequence (insertion and deletion)

Question 26

Duplication (chromosomal mutation)

Answer 26

Loss of part, or all, of a chromosome

Question 27

Inversion (chromosomal mutation)

Answer 27

Reverses direction of parts of a chromosome

Question 28

Translocation (chromosomal mutation)

Answer 28

Part of one chromosome breaks off and attaches to another chromosome

Question 29

Mutations

Answer 29

Chemical or physical agents that interact with DNA and may cause this Examples: Chemical - pesticides Physical - X-ray radiation

Question 30

Give an example of a good mutation

Answer 30

Insects can resist pesticides

Question 31

Give an example of a bad mutation

Answer 31

Sickle cell disease (dramatically change protein structure)

Question 32

Gene therapy

Answer 32

Transplantation of normal genes into cells in place of a missing or defective cell to correct issues

Question 33

How is gene therapy used?

Answer 33

To make cells more resistant to chemotherapy and tumour cells more sensitive

Question 34

What is ex vivo gene therapy?

Answer 34

Cells are modified outside of the patients body and transplanted

Question 35

What is in vivo gene therapy?

Answer 35

Cells are treated inside of the patients body

Question 36

Recombinant DNA

Answer 36

DNA produced by the combination of DNA from different sources

Question 37

Define xenotransplantation

Answer 37

Grafting, or transplanting, organs or tissues between a different species

Question 38

Hybridization

Answer 38

Breeding that involved crossing dissimilar organisms to bring together the best traits of both individuals

Question 39

Polyploid cell

Answer 39

A cell that contains more than two paired homologous sets of chromosomes, often stronger and larger