Unit 6

Question 1

Milk is _________ lowering the number of pathogenic bacteria using heat for a short period of time without changing its taste.

Answer 1

Pasteurized

Question 2

Beef jerky is an example of using _________ to preserve food.

Answer 2

Desiccation (super dry)

Question 3

What is UHT sterilized?

Answer 3

UHT, or Ultra High Temperature, is a food processing method that sterilizes liquid foods by heating them to a high temperature for a short time

Question 4

Degerms:

Answer 4

removes germs from something (like skin)

Question 5

Autoclave meaning:

Answer 5

Sterilize using high-pressure saturated steam at a specific temperature, typically 121°C, for a set period of time.

Question 6

Disinfect meaning

Answer 6

Eliminate most or all harmful microorganisms (except some spores) on its surface, typically using chemical agents.

Question 7

Filter meaning:

Answer 7

Remove particles or impurities from a liquid or gas by passing it through a porous material that traps contaminants

Question 8

Sanitized meaning:

Answer 8

Reduce the number of harmful microorganisms on a surface or object to a safe level, usually through cleaning or chemical treatment

Question 9

How can a bacterium gain antibiotic resistance?
2 ways

Answer 9

1. Random mutation
2. Or through gene transfer from another bacterium

Question 10

What happens when a person is given an antibiotic?

(think about antibiotic resistance)

Answer 10

It kills the cells that are not resistant but the ones that are survive and are able to multiply freely

Question 11

Transformation vs Transduction vs Conjugation

Answer 11

Transformation: when a cell picks up a piece of DNA from its surroundings

Transduction: when a bacteriophage transfers the gene from one cell to another

Conjugation: when R plasmids or R factors transfer the genes to other bacterial cells

Question 12

What is meant when a bacterium is said to become “resistant” to an antibiotic?

Answer 12

The bacterium is neither killed nor inhibited by the antibiotic

Question 13

When a patient is treated with antibiotics, the drug will __________ of all of the sensitive ______

Answer 13

kill or inhibit the growth; bacterial cells

Question 14

The process of acquiring antibiotic resistance by means of bacteriophage activity is called

Answer 14

Transduction

Question 15

What is a Missense mutation?

Answer 15

A single nucleotide change results in a different amino acid being incorporated into the protein, which can alter the protein’s function

Question 16

What is a Nonsense mutation?

Answer 16

A single nucleotide change converts a codon into a stop codon, prematurely terminating protein synthesis and often resulting in a nonfunctional protein

Question 17

What is a Silent mutation?

Answer 17

A single nucleotide change that does not alter the amino acid sequence of the protein due to the redundancy of the genetic code, typically having no effect on protein function

Question 18

What is a Frameshift insertion?

Answer 18

An extra nucleotide is added to the DNA sequence, shifting the reading frame and often resulting in a completely different and usually nonfunctional protein

Question 19

What is a Frameshift deletion?

Answer 19

A nucleotide is removed from the DNA sequence, shifting the reading frame and often leading to a drastically altered and usually nonfunctional protein

Question 20

Which mutation would not result in antibiotic resistance?

Answer 20

Silent mutation;

because there is no effect

Question 21

R-plasmids are most likely acquired via ___

Answer 21

bacterial conjunction

Question 22

The figure represents a Petri plate. The gray area is where bacteria A is growing(large), the black area is where bacteria B is growing (tiny). The white area is a zone where neither organism is growing. What is the best interpretation of what is observed on the plate?

Answer 22

Bacteria B is producing an antibiotic that inhibits the growth of bacteria A

Question 23

Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections?

Answer 23

Mycobacteria reproduce very slowly;

Mycobacteria take 12-24 hours to reproduce, in part due to their complex cell walls. Therefore, drugs against these bacteria must be administered over long periods of time

Question 24

An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug.

Answer 24

resistant;

A zone of inhibition measures the effectiveness of a drug; a disk with no zone at all would clearly indicate a microbe resistant to that drug.

Question 25

Susceptible:

(disk)

Answer 25

The microorganism is inhibited or killed by the antimicrobial agent, as evidenced by a clear zone of inhibition around the disk.

Question 26

Intermediate:

Answer 26

The microorganism shows partial inhibition, meaning it may be inhibited at higher concentrations of the antimicrobial or under specific conditions

Question 27

Synergistic:

Answer 27

The effect of two or more antimicrobial agents working together, where their combined effect is greater than the sum of their individual effects

Question 28

Antibiotic resistance:

Answer 28

This occurs when bacteria evolve to become resistant to the effects of an antimicrobial drug that was previously effective

Question 29

Selective toxicity:

Answer 29

This refers to the ability of a drug to harm pathogens without damaging the host’s cells, which is crucial for effective treatment

Question 30

Narrow spectrum of action:

Answer 30

This refers to an antimicrobial that targets a limited range of microorganisms

Ex. only Gram-positive bacteria

Question 31

A broad-spectrum antimicrobial:

Answer 31

This is an antibiotic that is effective against a wide range of microorganisms

Question 32

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans. This is an example of _____

Answer 32

selective toxicity

Question 33

Which activity can be shown to increase resistance among microbial populations?

taking ______ drugs for ______ infections;

Answer 33

taking antibacterial drugs for viral infections;

Taking antibacterial drugs when they are not needed (such as for viral infections) contributes to the development of antibiotic resistance. This misuse or overuse can encourage bacteria to evolve and become resistant to the drugs.

Question 34

How does resistance to drugs spread in bacterial populations?

Answer 34

Horizontal gene transfer between bacteria spreads R (resistance) plasmids

Question 35

Drug-resistant populations of microbes arise when ______

Answer 35

exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells