Z Micro Test 4

Front 1

Original mutation aka:

Back 1

“direct”

Front 2

Back mutation aka:

Back 2

“reversion”

Front 3

Salmonella typh. that are His+ are able to make

Back 3

the amino acid histadine

Front 4

Bacteria that can grow on a medium lacking histadine are referred to as:

Back 4

histadine positive (His+)

Front 5

Why can His+ grow on a medium lacking histadine?

Back 5

Because they can make their own.

Front 6

Give an example of a bacteria that we use a histadine medium with:

Back 6

Salmonella typh.

Front 7

These bacteria can mutate from His+ to His-

Back 7

Salmonella typh.

Front 8

Which Salmonella typh is “mutant”, His+ or His-?

Back 8

His-

Front 9

Define Auxotroph

Back 9

a mutant requiring a nutrient in the medium

Front 10

What type of mutation is it when Salmonella typh His+ mutates to His-?

Back 10

This is an ORIGINAL or DIRECT MUTATION

Front 11

What type of mutation is it when Salmonella typh His- mutates to His+?

Back 11

This is called a REVERSION or BACK MUTATION

Front 12

How do mutation begin?

Back 12

Either Spontaneously or Induced

Front 13

How frequently do SPONTANEOUS MUTATIONS occur?

Back 13

1/10 e10 – 1/10 e10 and Random

Front 14

What brings on INDUCED MUTATIONS?

Back 14

Exposure of cells to mutagens

Front 15

What kinds of categorical mutagens cause mutations?

Back 15

Chemical and Physical

Front 16

What are the main types of mutations?

Back 16

Point mutations and Frameshift mutations

Front 17

Name the types of POINT MUTATIONS

Back 17

Missense and Nonsense mutations

Front 18

Describe Missense mutations

Back 18

Base substitution, one letter gets replaced resulting in a different amino acid

Front 19

What is an example of a mis-sense mutation?

Back 19

Sickle-cell anemia

Front 20

What is sickle cell anemia?

Back 20

#6 in the plypeptide is normally Glutamic acid. The Aa is replaced by valine aa instead

Front 21

Describe Nonsense Mutations

Back 21

Codon that codes for AA is changed to a STOP codon

Front 22

What is an example of a nonsense mutation?

Back 22

Thalassemia

Front 23

What is thalassemia?

Back 23

The normal HG is 146 AAs. Instead there are 39 in Thalassemic cases. #40 is changed to a stop codon.

Front 24

Name the types of FRAMESHIFT MUTATI0NS

Back 24

Deletions and Insertions

Front 25

Give an example of a frameshift – deletion mutation

Back 25

cystic fibrosis (1479 instead of 1480)

Front 26

Give an example of frameshift – insertion mutation

Back 26

Huntington’s disease (hereditary)

Front 27

Mutagens can be …

Back 27

Chemical or Physical

Front 28

Give two examples of chemical mutagens

Back 28

nitrous acid HNO2 and 5-bromouracil 5-bU

Front 29

Summarize the mutation caused by Nitrous acid HNO2

Back 29

If you treat the A with HNO2, the A will no longer bond with T, but C instead. The next replication proceeds normally. Change AT pair into CG pair.

Front 30

Summarize the mutation caused by 5-bromouracil 5-bU

Back 30

This chemical takes the place of Thymine in the replication chain. This strand now has GCACG -> CG5-buGC -> GCGCG (the 5-bu pairs with G) change AT pair into GC pair

Front 31

Give two examples of physical mutagens

Back 31

Radiations: Ionizing radiation and Nonionizing radiation

Front 32

What does Ionizing Radiation do?

Back 32

Damage DNA and chromosomes. They also break bonds in strands. X-rays eject electrons.

Front 33

What causes Nonionizing radiation?

Back 33

UV

Front 34

Describe Thymine dimers”

Back 34

two thiamines bond, causing a “dimmer

Front 35

What can a Thymine dimers do?

Back 35

can cause melanoma

Front 36

What are the two types of repair?

Back 36

Light and dark repair

Front 37

Describe light repair

Back 37

visible light breaks the bond

Front 38

Describe dark repair

Back 38

the mutant section is cut and replaced by DNA polymerase

Front 39

Describe positive (direct) selection

Back 39

Take a petri dish with a medium containing penicillin and we grow bacteria – only bacteria that is resistant to penicillin will grow. This is positive selection.

Front 40

What are the two types of Penicillin?

Back 40

Penicillin S and Penicillin R (resistant)

Front 41

What is used in the replica plating test to identify mutants?

Back 41

S. typhimurium, Hist+ and hist1

Front 42

What is another name for direct selection?

Back 42

Positive selection

Front 43

What is another name for indirect selection?

Back 43

Negative selection or replica plating

Front 44

Describe the procedure for positive (direct) selection

Back 44

Take a petri dish with a medium containing penicillin and we grow bacteria – only bacteria that is resistant will grow. This is positive selection.

Front 45

Describe the procedure for Negative (indirect) selection

Back 45

Take a petri dish with a medium containing histidine – this plate is called MASTER. Both His+ and His- will grow. We prepare two plates. The first one has a medium containing Histidine. The second one with a medium lacking Histidine. We take sterile filter paper and we press it onto the colonies. We then press it clearly onto the two new plates. The medium with histadine will receive all transferred (same as master). The medium lacking Histadine will only grow the His+ colonies. The missing colonies are His-