Exam Review

Question 1

What is a missense mutation?

Answer 1

A single nucleotide change results in a different amino acid.

Question 2

What is a nonsense mutation?

Answer 2

A mutation that creates a stop codon, terminating translation early.

Question 3

What occurs during an insertion mutation?

Answer 3

Addition of one or more nucleotides, potentially causing a frameshift.

Question 4

What is a deletion mutation?

Answer 4

Removal of one or more nucleotides, potentially causing a frameshift.

Question 5

Define a silent mutation.

Answer 5

A mutation that does not change the amino acid sequence.

Question 6

How does PCR affect the number of DNA fragments?

Answer 6

The number of DNA fragments doubles each cycle.

Question 7

What is a similarity between DNA and RNA?

Answer 7

Both synthesized in the 5’ to 3’ direction.

Question 8

What are recombinant organisms?

Answer 8

Have foreign DNA integrated into their genome.

Question 9

List the methods through which recombinant organisms can acquire genes.

Answer 9

• Conjugation
• Transduction
• Transformation

Question 10

What are Single Nucleotide Polymorphisms (SNPs)?

Answer 10

Variations in a single DNA base.

Question 11

What is the purpose of CRISPR-Cas9 in bacteria?

Answer 11

adaptive immunity

Question 12

What is the application of CRISPR-Cas9 in science?

Answer 12

Used for gene editing by guiding nucleases to specific DNA locations.

Question 13

What is gene therapy?

Answer 13

Inserts functional genes to correct genetic disorders.

Question 14

Does gene therapy pass changes to offspring?

Answer 14

Does not necessarily pass changes to offspring.

Question 15

What characterizes eukaryotic chromosomes?

Answer 15

Have histone proteins, multiple linear chromosomes, and a nucleus.

Question 16

Describe the DNA antiparallel structure.

Answer 16

One strand runs 5’ to 3’, while the complementary strand runs 3’ to 5’.

Question 17

What causes frameshift mutations?

Answer 17

Caused by insertions or deletions.

Question 18

What is transduction?

Answer 18

Transfer of bacterial genes via bacteriophages.

Question 19

What are transposons?

Answer 19

Mobile genetic elements that can alter DNA.

Question 20

What is the function of gel electrophoresis?

Answer 20

Separates DNA by size using an electric current.

Question 21

What is the start codon for translation initiation?

Answer 21

AUG.

Question 22

What are sterilization methods?

Answer 22

Requires agents like sporicides.

Question 23

List factors affecting antimicrobial agents.

Answer 23

• Microbial type
• Number
• Environment (pH, temperature)
• Dosage

Question 24

What halogen is widely used in water treatment?

Answer 24

Chlorine.

Question 25

What is the role of alcohols in disinfection?

Answer 25

Disrupt membrane lipids.

Question 26

What does antimicrobial action on cell walls do?

Answer 26

Blocks synthesis or digests peptidoglycan.

Question 27

What sterilization methods achieve complete sterilization?

Answer 27

* Autoclaving * Ionizing radiation

Question 28

Define thermal death time (TDT).

Answer 28

Time required to kill at a given temperature.

Question 29

What is the thermal death point (TDP)?

Answer 29

Minimum temperature needed to kill in 10 minutes.

Question 30

Disinfectants are used on _______.

Answer 30

surfaces.

Question 31

Antiseptics are used on _______.

Answer 31

living tissue.

Question 32

Cold & desiccation are considered _______.

Answer 32

bacteriostatic, not bactericidal.

Question 33

What does physical removal of microbes involve?

Answer 33

Filtration removes microbes without killing them.

Question 34

What is the therapeutic index (TI)?

Answer 34

Higher TI values (e.g., 100) are safer.

Question 35

What is a characteristic of biofilm infections?

Answer 35

Biofilm bacteria express different genes, altering antibiotic susceptibility.

Question 36

How do you choose antibiotics?

Answer 36

Choose the antibiotic with the highest therapeutic index.

Question 37

What is a superinfection?

Answer 37

Overgrowth of resistant microbes after antibiotic therapy.

Question 38

List mechanisms of antimicrobial resistance.

Answer 38

* Enzymes inactivate drugs (e.g., beta-lactamase) * Decreased drug uptake * Drug elimination via pumps * Altered drug binding site * Alternative metabolic pathways

Question 39

What is conjugation in horizontal gene transfer?

Answer 39

DNA transfer via pili.

Question 40

What is transformation in horizontal gene transfer?

Answer 40

Uptake of free DNA.

Question 41

Example of antibiotics that inhibit cell wall synthesis?

Answer 41

penicillin.

Question 42

antibiotics that inhibit protein synthesis?

Answer 42

tetracyclines.