HW 11-13

Question 1

The LD50 of a pathogen is defined as:
1)The number of pathogen cells introduced per host required to kill 50% of host organism
2)The length of time required for a pathogen to kill 50% of host organisms
3)The number of pathogen cells required to generate symptoms in 50% of host organisms
4)The probability that an infection with a particular pathogen will lead to death of the host.

Answer 1

The number of pathogen cells introduced per host required to kill 50% of host organism

Question 2

Bacteroides

Answer 2

Very active in digesting complex polysaccharides

Question 3

Staphylococcus

Answer 3

The most abundant genus in the skin microflora

Question 4

Helicobacter

Answer 4

Causes gastric ulcers and cancer

Question 5

Clostridium

Answer 5

Causes severe disease if parts of the microbiome are depleted

Question 6

Methanobrevibacter

Answer 6

A rare Archaea in the microbiome

Question 7

Siderophore

Answer 7

Iron acquisition by the pathogen

Question 8

Capsule

Answer 8

Evasion of phagocytosis

Question 9

Enterotoxin

Answer 9

Causes diarrhea

Question 10

Exotoxin

Answer 10

Disrupts host cell function

Question 11

The most abundant bacteria in the human skin microflora are Gram- _____cocci

Answer 11

positive

Question 12

Inflammation of the membranes of the central nervous system is called:

Answer 12

meningitis

Question 13

Which of the following is FALSE about the lymphatic system?
1)It delivers water to the extremities
2)It contains no erythrocytes
3)It contains T and B cells
4)It contains macrophages
5)It drains water from the extremities

Answer 13

It delivers water to the extremities

Question 14

Which of the following is used by phagocytes to kill bacteria?
1)Antibiotics
2)Hydrogen peroxide
3)Apoptosis
4)Nucleases
5)Granzymes

Answer 14

Hydrogen Peroxide

Question 15

B cell

Answer 15

Presents antigens to T cells

Question 16

Th2 cell

Answer 16

Activates B cells to divide and differentiate

Question 17

Tc

Answer 17

kills virus-infected host cells

Question 18

Plasma cell

Answer 18

Produces antibodies

Question 19

The enormous diversity of antibody-encoding genes is generated by the process of:

Answer 19

VDJ recombination

Question 20

Macrophages use Toll-Like Receptor 4 to recognize ____ produced by bacterial cells.

Answer 20

LPS

Question 21

Describe TWO methods the human immune system uses to avoid producing antibodies that cause an autoimmune response

Answer 21

T cells go through tolerance, so they cannot recognize self-antigens, and B cells go through tolerance, so they cannot recognize self-antigens. These two facts provide double protection against an autoimmune reaction.

Question 22

Which disease is commonly spread by Direct Host-to-Host transmission?
1)Cholera
2)Cancer
3)AIDS
4)Lyme disease
5)Malaria

Answer 22

AIDS

Question 23

Mobidity

Answer 23

The number of new disease cases in a population is a time period

Question 24

Mortality

Answer 24

The number of new deaths in a population in a time period

Question 25

Prevalence

Answer 25

The number of total, old and new, cases in a population in a time period

Question 26

Endemic

Answer 26

A disease that is constantly present in a population over time

Question 27

A large increase in disease cases produced by a contaminated water source is called a ____ epidemic

Answer 27

common-source

Question 28

A living agent, such as a mosquito, that spreads an infectious disease is called a:

Answer 28

vector

Question 29

A disease that passes from an animal population to humans is called a:

Answer 29

zoonosis

Question 30

Describe how Immunity works. What must be true about the population for this to occur? How are vulnerable individuals in the group protected?

Answer 30

To obtain herd immunity, a large percentage of the population must be immune to a disease, either through natural immunity, prior infection, or vaccination. This prevents that infectious agent from spreading in the population, thus protecting the small number of individuals that are vulnerable.