Ch. 9 microbial genetics

Question 1

LAC operon

Answer 1

Present: binds to a repressor molecule, allowing translation to occur
Absent: the repressor molecule will inhibit RNA polymerase from transcribing RNA.
- Genes are involved in turning lactose into proteins.

Question 2

3 Forms of bacterial genetic exchange

Answer 2

• conjugation
• transduction
• transformation

Question 3

Direct Contact conjugation

Answer 3

1. conjugation pilus of the donor links to recipient
2. F factor (Plasmid info) is copied and transferred to the recipient
3. A partial chromosome is copied and relayed into the recipient cell, where it is integrated into the bacterial cell.

Question 4

Transformation of exogenous DNA

Answer 4

1. External DNA fragment will bind to protein receptor on outside of cell.
2. DNA fragment will become single stranded and simple to enter the cell
3. DNA will align with corresponding DNA sequence within the cell
4. DNA will incorporate into the bacterial DNA.
5. At this point external DNA is now incorporated fully into the original bacterial DNA.

Question 5

Transduction via virus vectors

Answer 5

1. Virus will inject DNA into host cell
2. Viral proteins replicate within cell
3. Some bacterial chromosomal information becomes incorporated into virus
4. once lysed, virus transduces the original host bacterial information into another host.

Question 6

Plasmid

Answer 6

small circular form of DNA
typically in prokaryotic organisms, playing a role in survival

Question 7

which direction does DNA polymerase read from?

Answer 7

from 5’ to 3’ direction

Question 8

Helicase

Answer 8

breaks hydrogen bonds within DNA strand

Question 9

topoisomerase

Answer 9

prevents dna from coiling once separated

Question 10

SS binding protein

Answer 10

prevents dna from binding again

Question 11

DNA pol 1

Answer 11

replaces primers with DNA

Question 12

Ligase

Answer 12

mends okazaki segments

Question 13

Describe bidirectional bacterial replication

Answer 13

1. Ori represents region that replication begins
2. two replication forks move away from one another in opposite directions
3. replication forks continue circular until meet at termination sequence
4. Each new strand contains original strand. (semiconservative)

Question 14

Rolling replication

Answer 14

present in plasmid replication,
- polymerase begins on the plasmid
- replicates and moves with SS binding protein replicating.
- one strand is replicated

https://www.youtube.com/watch?v=jmWuju1S9_E

Question 15

Central Dogma of biology

Answer 15

the fundamental flow of DNA to RNA to Protein.

Question 16

Can mRNA be read directly after synthesis?

Answer 16

No, it must undergo intron removal and exon binding within the nucleolus.

Question 17

Difference between DNA and RNA

Answer 17

• two prime -OH group
• single-stranded
• utilizes Uracil, not thymine

Question 18

Transcription

Answer 18

-RNA polymerase makes a copy of template strand from 5’ to 3’.
- tRNA will bring copied strand to ribosome to make protein.

Question 19

RNA processing

Answer 19

• Primary mRNA transcript contains Introns that are excised and Exons that are kept and bound together following intron removal
• This occurs in the nucleus and allows mRNA to be translated in the cytoplasm

Question 20

tRNA

Answer 20

carriers of amino acids to form peptide bonds in the ribosome

Question 21

stop codons

Answer 21

• UAA
• UAG
• UGA

Question 22

Riboswitch

Answer 22

• regulates translation at the ribosome
• binds to mRNA
• Ligand binding to mRNA can inhibit ribosome protein synthesis.

Question 23

What does Lac I code for?

Answer 23

codes for lac operon that inhibits the repressor protein

Question 24

Define Horizontal gene transfer

Answer 24

genetic material is shared between two organisms that are not parents and offspring.

Question 25

Transformation with DNA fragments or plasmid

Answer 25

DNA fragments can be integrated or degraded to be incorporated OR A plasmid can be taken into a cell completely, allowing it to remain in the cell unintegrated, but it will affect the cell.

Question 26

Base substitution

Answer 26

replaces one amino acid in codon

Question 27

missense mutation

Answer 27

changes codon and results in non functioning protein

Question 28

silent mutation

Answer 28

single nucleotide change that doesn't result in misfunctioning protein

Question 29

nonsense mutation

Answer 29

results in an early stop codon being produced

Question 30

frameshift mutation

Answer 30

shifts amino acids to shift downstream - resulting in a misfunctioning protein, short protein, or early stop codon.

Question 31

AMES test

Answer 31

tests if a chemical can cause mutation

Question 32

AMES test with bacteria

Answer 32

testing on his(-) bacteria. Control contains no histidine, the pother does and is treated with chemical. - presence of colonies shows that mutations occured.