8. Olds (1st exams - 2)

Question 2

Give 2 unique characteristics of viruses as compared to bacteria.

Answer 2

Virus
1. Need living hosts for survival
2. Acellular
3. Assembly line system

Bacteria
1. Able to survive outside a host
2. Unicellular
3. Binary fission

Question 3

Why is PCR more sensitive than other diagnostic tests?

Answer 3

In PCR, the target is amplified so as “n amount of PCR cycles = 2n amplicons”, which makes it easier to find the desired nucleotide sequences.

Question 4

Give 1 physical barrier and 1 physiological barrier of the GIT.

Answer 4

physical barrier
* Intestinal epithelial cells
* Mucus layer

physiological barrier
* Stomach pH
* Peristalsis

Question 5

Draw the NA replication process of ssDNA, and include the template strand, enzymes, process names, etc.

Answer 5

DRAWING

insert Transcription (from DdDp to DdRp) and Translation (Ribosomes to protein)

Question 6

Draw the components of the mucociliary escalator and explain how it helps protect the
body.

Answer 6

DRAWING

• Goblet cells, mucus, cilia (sabi rin ni doc pwede raw idagdag ang epithelial cells)
• Microbes that enter the respiratory system are trapped by the mucociliary escalator.
• Goblet cells continuously secrete mucus, which traps the inhaled microbes and is constantly pushed upward by the cilia for removal from the body.

Question 7

Two ways how the body/immune system recognizes infected
cells

Answer 7

1. Production of viral glycoproteins➡️recognized by NK cells
2. Displays MHC I + endogenous Ag➡️recognized by cytotoxic T-lymphocytes

Question 8

neutralizing Abs and explain

Answer 8

• Virus neutralization (eto lang ‘yung sinagot ko kasi akala ko eto lang need dahil may word na “neutralize” somewhere sa question LMFAO)
• Activation of complement proteins via the classical activation pathway
• Opsonization
• Antibody-dependent cell-associated cytotoxicity

Question 9

In tabular form, differentiate primary and secondary antibody response using 4
parameters.

Answer 9

Primary Ab response & Secondary Ab response sa?
* Main Immunoglobulin
* Lag Time
* Response Duration
* Response Strength

Question 10

Define, draw, and describe ADCC (Antibody-Dependent Cell-mediated Cytotoxicity)

Question 11

Draw and describe indirect ELISA.

Answer 11

ILLUSTRATION

• Test serum is tested for presence of Abs against Ag of interest (Ag is pre-adsorbed at bottom of well)
• Specific Ab, if present in test serum, binds to Ag, & is then bound by enzyme-labelled secondary Ab
• Substrate added to well reacts with enzyme on secondary Ab leading to a color change in liquid in well