Lesson Five

Question 1

DNA stands for

Answer 1

Deoxyribose nucleic acid

Question 2

DNA makes up

Answer 2

Chromosomes

Question 3

Two types of nucleic acids

Answer 3

DNA and RNA (chains of nucleotides)are involved in functioning of chromosomes in protein synthesis

Question 4

Shape of DNA is referred to as

Answer 4

Double helix

Question 5

Nucleotides are composed of

Answer 5

Nitrogen bases, phosphoric acid, 5 carbon sugar (Deoxyribose)

Question 6

Purines

Answer 6

Double ring

T and C

Question 7

Pyrimidines

Answer 7

Single ring

A and G

Question 8

Alternating sugar and phosphates make up the

Answer 8

Rungs of the backbone

Question 9

Adenine bonds to…

Answer 9

Thymine (2 hydrogen bonds)

Question 10

Guanine always bonds to…

Answer 10

Cytosine (3 hydrogen bonds)

Question 11

The bases cannot bond any other way because…

Answer 11

2 purines would overlap and 2 pyrimidines would be too short to form the rungs of the ladder.

Question 12

The double strand is held in place by…

Answer 12

Hydrogen bonds between the bases

Question 13

As DNA lengthens, it…

Answer 13

Twists into a double helix

Question 14

Functions of DNA (3)

Answer 14

1. Replicates itself so each new cell has complete identical copy
2. Controls the activities of a cell by product ing proteins (combinations of proteins determine characteristics of organisim)
3. Undergoes occasional mutations (mistakes in replication) which produces variety

Question 15

Step one in DNA replication

Answer 15

DNA molecule becomes untwisted, by the enzyme helicase breaking up the weak hydrogen bonds between the nitrogenous base pairs

Question 16

Step two in DNA replication

Answer 16

New complementary nucleotides (always present in nucleus) move into place and pair with exposed strands. The enzyme DNA polymerase assists with the base pairing

Question 17

Step 3 in DNA replication

Answer 17

The adjacent nucleotides become joined together, the enzyme Ligase glued the alternating sugar phosphate backbone together

Question 18

Step 4/5

Answer 18

2 complete DNA are now present which are identical to each other. Both strands will wind back to original helical shape

Question 19

DNA replication is called…

Answer 19

Semi conservative because it has old strand (parent) and new strand (daughter).

Question 20

Recombinant DNA is…

Answer 20

DNA which has genes from 2 different organisims, often produced in the lab by introducing foreign genes into a bacterial plasmid which makes new combination of DNA

Question 21

Most common organism to be a vector for recombinant DNA

Answer 21

Plasmids

Question 22

Steps of producing recombinant DNA

Answer 22

Plasmid is removed from bacteria and has foreign gene inserted. Enzyme breaks plasmid DNA and then new foreign DNA can be attached to plasmid. Ligase then sticks the foreign DNA to the plasmid to make it whole.

Question 23

Viral DNA can also be used….

Answer 23

As a vector to carry recombinant DNA into a cell. When a virus containing recombinant DNA infects a cell, the viral DNA enters. Then it reproduces more viruses.

Question 24

Viral vectors allow…

Answer 24

Cloning of a particular gene

Question 25

Viral vectors also are used to crate

Answer 25

Genomic libraries

Question 26

Summary of Recombinant DNA

Answer 26

Certain genes can be inserted into bacteria and then these bacteria will produce these genes.

Question 27

Uses of recombinant DNA

Answer 27

1. Generate DNA library, which will catalogue all the base sequences of known genes.
2. Identify specific genes
3. Produce synthetic copies of genes
4. Insert genetic material into chromosomes to make it generically better

Question 28

Unique characteristics of DNA

Answer 28

Two strands, a+t, c+g

Pentose sugar is deoxyribose (ribose with one less oxygen)

Question 29

Unique characteristics of RNA

Answer 29

One strand, A+U, C+G,

Pentode sugar is ribose