8 Fungi and Parasites (Midterm 1 up to here)

Question 1

These organisms can be either unicellular or multicellular.

Answer 1

Fungi

Question 2

Internal, membrane-bound structures of fungi are similar to those of eukaryotes, but differences b/w fungi and euk. are found in the cell envelope of fungi. What are these two differences?

Answer 2

1. Ergosterol > sterol cmpnd found in fungal plasma membrane

2. Chitin > rigid, multi-layered carb structure (like bacterial PG) lying above plasma membrane

Question 3

Fungi exist as two diff morphological types:

1. ____
2. ____

Answer 3

1. Yeasts

2. Molds

Question 4

Are yeasts single-celled or multi-cellular?

Answer 4

yeasts = single-celled fungi

Question 5

Are molds single-celled or multi-cellular?

Answer 5

molds = multicellular fungi

Question 6

This type of fungus reproduces by budding.

Answer 6

yeast

Question 7

This type of fungus reproduces via a “spore” stage.

Answer 7

mold

Question 8

This type of fungus forms filamentous structures called “hyphae”, a collection of which is called a “mycelium”.

Answer 8

mold

Question 9

What are dimorphic fungi able to do?

Answer 9

Alternate b/w yeast and mold forms, depending on the envir

Question 10

T or F: Relatively few fungi cause disease, but the diseases are usually severe.

Answer 10

T

Question 11

List the three types of fungal diseases.

Answer 11

1. Hypersensitivity diseases
2. Mycotoxicoses
3. Mycoses

Question 12

Fungal hypersensitivity diseases are allergic responses to fungal ____ and ____.

Answer 12

spores, metabolites

Question 13

What is a mycotoxicosis?

Answer 13

A poisoning due to ingesting a fungal metabolic product.

Question 14

What is a mycosis?

Answer 14

An infection due to growth of fungus in/on a human host.

Question 15

How are mycoses classified?

Answer 15

According to how DEEPLY the fungus penetrates tissues.

Question 16

3 types of mycoses?

Answer 16

1. Cutaneous (superficial)
2. Subcutaneous
3. Systemic (deep)

Question 17

Cutaneous mycoses are caused by ______, fungi who use keratin as a nutrient source

Answer 17

dermatophytes

Question 18

These types of mycoses are often associated w/ cuts or wounds.

Answer 18

Subcutaneous mycoses

Question 19

These are fungal infections of internal organs.

Answer 19

systemic (deep) mycoses

Question 20

These types of mycoses are associated w/ fungal growth on the outermost layers of the skin, nails, etc.

Answer 20

cutaneous (superficial) mycoses

Question 21

These types of mycoses are characterized by fungal infections of deeper skin and subcutaneous tissues.

Answer 21

Subcutaneous mycoses

Question 22

These types of mycoses can be VERY SEVERE.

Answer 22

Systemic (deep) mycoses

Question 23

This type of fungus is found asymptomatically as part of normal human flora

Answer 23

Candida (a yeast)

Question 24

How are fungal infections diagnosed in the lab? (2)

Answer 24

1. Direct microscopic examination

2. Growth on culture media > biochemical identification

Question 25

Why is it difficult to achieve "selective toxicity" w/ antifungal medications?

Answer 25

Fungi and humans are BOTH eukaryotic, so meds that target fungal cells can also target human cells > potential toxicity

Question 26

Anti-fungals usually have two modes of action. What're they?

Answer 26

1. Target fungal cell envelope | 2. Interfere w/ DNA/RNA synthesis

Question 27

What're parasites?

Answer 27

organisms that reside in or on a mammalian host as part of its lifecycle

Question 28

T or F: Parasites can be either eukaryotic or prokaryotic.

Answer 28

F Parasites are only eukaryotic

Question 29

What're the two taxonomic gps of parasites?

Answer 29

1. Protozoa | 2. Helminths (metazoa)

Question 30

These types of parasites are microscopic only

Answer 30

protozoa

Question 31

These types of parasites can be either microscopic OR macroscopic

Answer 31

helminths

Question 32

These types of parasites are multicellular worms

Answer 32

helminths

Question 33

These types of parasites are similar to yeast in size and internal complexity

Answer 33

protozoa

Question 34

These types of parasites have differentiated organs/tisues

Answer 34

helminths

Question 35

What're the two morphological forms that some protozoa can alternate between?

Answer 35

1. Trophozoite | 2. Cyst

Question 36

Trophozoite or cyst? Metabolically active and replicative protozoan form found inside the host.

Answer 36

Trophozoite

Question 37

Trophozoite or cyst? Dormant, non-replicating form of protozoan w/ a thickened wall to facilitate survival. Also, this is the form that's gets transmitted from host to host.

Answer 37

Cyst

Question 38

What're the three types of helminths that're of human importance?

Answer 38

1. Nematodes 2. Tapeworms 3. Flukes

Question 39

Are helminths usually microscopic or macroscopic?

Answer 39

Macroscopic

Question 40

How do helminths reproduce?

Answer 40

Via eggs that hatch into larvae and grow into adult worms

Question 41

Infective form of helminth?

Answer 41

Eggs/larvae

Question 42

What're the two taxonomic gps of parasites?

Answer 42

1. Protozoa | 2. Helminths (metazoa)

Question 43

This form of helminth causes symptoms of disease.

Answer 43

Adult worms

Question 44

How're giardiasis parasitic infections transmitted?

Answer 44

fecal-oral route

Question 45

Is giardiasis caused by helminths or protozoa?

Answer 45

Protozoa

Question 46

How is the cyst form of Giardia lamblia (causes giardiasis) converted into the trophozoite form in vivo?

Answer 46

Stomach digestive enzymes degrade the cyst wall, triggering conversion to trophozoite form in the intestinal tract

Question 47

T or F: Amoebic meningitis is a common CNS infection caused by Naegleria fowleri (parasitic protozoan)

Answer 47

F This type of CNS infection is extremely rare.

Question 48

Amoebic meningitis has a fatality rate of almost 100%.

Answer 48

T

Question 49

What's the infective form of N. fowleri? a) Amoeboid trophozoite b) Flagellate trophozote c) Cyst

Answer 49

a)

Question 50

From where must N. fowleri enter through in order to cause infecton?

Answer 50

Nasal mucosa

Question 51

Another name for N. fowleri?

Answer 51

"Brain-eating amoeba"

Question 52

What is one of the most common helminth infections?

Answer 52

Pinworms

Question 53

How're parasitic infections usually diagnosed?

Answer 53

Microscopic examination

Question 54

T or F: There're few anti-parasitic agents in clinical use

Answer 54

T