Micro Exam 2

Question 1

Inducible operons

Answer 1

Inducible operons are turned on in reponse to a metabolite (a small molecule undergoing metabolism) that regulates the operon

Question 2

Transduction requires a(n) ________ to move DNA from one bacterial cell to another.

Answer 2

bacteriaphage

Question 3

What is the hallmark of all horizontal gene transfers?

Answer 3

Transfer of DNA between organisms of the same generation.

Question 4

Which of the following is a method of vertical gene transmission

Answer 4

cell division

Question 5

Which of the following genetic elements is transcribed into a single mRNA?

Answer 5

structural genes

Question 6

here on the DNA strand does a repressor bind

Answer 6

the operator

Question 7

Thymine dimers result from

Answer 7

nonionizing radiation

Question 8

conjugation

Answer 8

cell to cell contact via pili

Question 9

transduction

Answer 9

The process by which a virus transfers genetic material from one bacterium to another

Question 10

operon

Answer 10

a functioning unit of DNA containing a cluster of genes under the control of a single promoter.

Question 11

What are the two ways mutations can be repaired?

Answer 11

) Damage to DNA caused by UV radiation can be repaired by enzymes that cut out and replace the damaged portion of DNA.

2) Light-repair enzymes repair thymine dimers in the presence of visible light.

Question 12

catabolite regression

Answer 12

a regulatory mechanism by which the expression of genes required for the utilization of secondary sources of carbon is prevented by the presence of a preferred substrate.

Question 13

what is the function of a plasmid

Answer 13

used as a vector to amplify and replicate genes. A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA.

Question 14

how does radiation kill cells ?

Answer 14

he inhibition of cellular proliferation is the mechanism by which radiation kills most mammalian cells.

Question 15

how is disk diffraction used ?

Answer 15

n diagnostic laboratories, the disk diffusion test is used to determine the susceptibility of clinical isolates of bacteria to different antibiotics.

Question 16

How to tell if antibiotic is effective

Answer 16

large zone of inhibition

Question 17

What are disinfectants?

Answer 17

Disinfectants are used on non-living things, such as countertops and handrails, to kill the microorganisms living on that inanimate surface

Question 18

What are antiseptics ?

Answer 18

Antiseptics are used on living organisms, such as human skin, to kill any microorganisms living on the bodies surface

Question 19

constitutive genes

Answer 19

expressed at a fixed rate always there

Question 20

nonsense mutation

Answer 20

a mutation that introduces a stop codon into the genetic code and prevents the protein from being made completely.

Question 21

frameshift mutation

Answer 21

single letter is inserted or deleted resulting in shift of reading frame

Question 22

sillent mutation

Answer 22

a mutation in which a single nucleotide base is changed, but that change does not effect the amino acid sequence.

Question 23

missense mutation

Answer 23

A missense mutation is a point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid.

Question 24

lytic cycle

Answer 24

The lytic cycle involves the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell.

Question 25

lysogenic cell

Answer 25

involves the incorporation of the viral genome into the host cell genome,

Question 26

sterilization

Answer 26

destruction of all microbial life

Question 27

bacteriostatic

Answer 27

inhibiting not killing microbes

Question 28

Asepsis

Answer 28

absence of significant contamination

Question 29

DNA helicase

Answer 29

unwinds DNA

Question 30

DNA ligase

Answer 30

joins okasaki fragments together

Question 31

What do gyrase and toprimase do

Answer 31

relax DNA strands

Question 32

What doers RNA polymerase do?

Answer 32

remove RNA primers

Question 33

What does DNA polymerase do?

Answer 33

adds nucleotides to DNA strand in 5 -3 direction.

Question 34

Explain pre-transcriptional regulation of gene expression in bacteria.

Answer 34

wo genetic mechanisms known as repression and induction regulate the transcription of mRNA and consequently the synthesis of enzymes from them. These mechanisms control the formation and amounts of enzymes in the cell

Question 35

lac operon

Answer 35

The lac operon is an example of inducible control because the presence of lactose turns on transcription of the genes for its own metabolism.

Question 36

trp operon

Answer 36

The trp operon is an example of repressible control because it uses proteins bound to the operator sequence to physically prevent the binding of RNA polymerase.

Question 37

Compare and contrast protein synthesis in prokaryotes and eukaryotes. Why are they different?

Answer 37

.In Prokaryotic cells, Transcription and Translation Can Occur at the Same Time(coupled)
2.Occurs in nucleus of eukaryotes and cytoplasm in prokaryotes
3.Eukaryotes have have variations in the number of chromosomes between species

Question 38

First step of DNA replication

Answer 38

The first step is to unwind the double helix structure of the DNA molecule, and ‘unzip’ the strands

Question 39

second step of DNA replication?

Answer 39

replication fork forms