Chapter 12

Question 1

What are fungi?

Answer 1

• Fungi include molds, yeasts, and mushrooms.
• They are chemoheterotrophic organisms that decompose dead plant matter.

Question 2

How do fungi obtain their nutrients?

Answer 2

• Fungi are aerobic and facultatively anaerobic organisms that digest and absorb nutrients from their environment.
• Chemoheterotrophs

Question 3

What is the primary component of fungal cell walls?

Answer 3

Fungal cell walls are primarily made of chitin

Question 4

How do fungi reproduce?

Answer 4

Fungi reproduce by means of spores, which are used for both dispersal and reproduction.

Question 5

How can fungi be identified?

Answer 5

Fungi can be identified based on their physical appearance, including colony characteristics, vegetative structures, and reproductive spores.

Question 6

Fungi

How do molds reproduce?

Answer 6

Molds reproduce through the formation of both vegetative and aerial hyphae, which bear reproductive spores.

Vegatative structure: vegetative hyphae
Reproductive structure: aerial hyphae

Question 7

Fungi

What is a coenocytic mold?

Answer 7

It has no septa, they are long cells with many nuclei

Question 8

Fungi

What are the two primary types of spore formation in molds?

Answer 8

Molds produce spores through sexual and asexual reproduction.

Question 9

Fungi

What is the difference between sexual and asexual reproduction in molds?

Answer 9

• Sexual reproduction involves the fusion of nuclei from two opposite mating strands
• Asexual reproduction occurs through processes like fragmentation and the formation of specialized spores

Question 10

Fungi

What are asexual spores in molds?

Answer 10

Asexual spores include:
* Conidiospores, which can be unicellular or multicellular and are not enclosed in a sac
* Sporangiospores, which form within a sporangium or sac.

Question 11

Fungi

What are sexual spores in molds?

Answer 11

Zygospores: fusion of to similar gametes

Question 12

Fungi/Mold

Aspergillius is the name of a mold genus. What health problem can aspergillus cause?

Answer 12

Aspergillus causes bleeding in the lungs. It is obtained by inhaling Aspergillus spores.

Question 13

Fungi/Mold

What is valley fever and what are the health problems it can cause?

Answer 13

Valley fever grows in the southwest, in sandy soils. Once inhaled, it changes form and reproduces. The growing fungus can fill the lungs causing infection, pneumonia and other problems.

Question 14

Fungi/Mold

What is rhizopus? What is the cycle of reproduction?

Answer 14

Rhizopus is a mold in bread.

Question 15

Fungi/Yeast

How do yeast grow compared to mold?

Answer 15

Yeast reproduce through a form of asexual reproduction known as **budding **. They only reproduce sexually when they are nutrient starved.

Mold reproduce asexually (condiospore & sporangiospore) and sexually (zygospore) using spores.

Question 16

Yeasts are unicellular fungi that use an asexual form of reproduction called “budding”. What is budding?

Answer 16

Budding: outgrowth or bud due to cell division at one particular site

Example: Saccharomyces (brewers yeast)

Question 17

What is dimorphism in fungi?

Answer 17

Dimorphism in fungi refers to the ability of certain fungi to exist in two different forms of growth: moldlike and yeastlike.

Question 18

Dimorphism

In diamorphism fungi, mold-like forms are able to grow. What two forms can they take?

Answer 18

1. Vegatative hyphae
2. Aerial hyphae

Question 19

Dimorphism

What characterizes the yeastlike form of dimorphism?

Answer 19

The yeastlike form is characterized by budding.

Question 20

How does temperature influence the growth forms of pathogenic fungi?

Answer 20

Pathogenic fungi exhibit temperature-dependent dimorphism, with a yeast-like form at 37°C and a mold-like form at 25°C.

Question 21

What is a lichen?

Answer 21

Green Algea and a fungus symbiotically living together.

Question 22

What are the three types of lichen?

Answer 22

1. Crustose: encrusted
2. Fructose: fingerlike projections
3. Foliose: leaflike

Question 23

Where do lichen grow?

Answer 23

Newly exposed soil or rock

Question 24

What are the six different types of algae that were presented in the lecture?

Answer 24

The six types of algae mentioned in the lecture are
1. Brown algae
2. Red algae
3. Green algae
4. Diatoms
5. Dinoflagellates
6. Water Molds

Question 25

What types of algae are considered phytoplankton?

Answer 25

Diatoms and dinoflagellates are considered phytoplankton. They play a significant role in aquatic ecosystems.

Question 26

Which type of algae is not photosynthetic?

Answer 26

Water molds are not photosynthetic; they are filamentous, heterotrophic protists.

Question 27

What is PSP (Paralytic Shellfish Poisoning)? How do humans get PSP? What about Domoic acid poisoning?

Answer 27

• ** PSP** is a type of seafood poisoning caused by the consumption of shellfish contaminated with toxins produced by certain dinoflagellates.
• Domoic acid poisoning, on the other hand, results from the ingestion of seafood contaminated with domoic acid, which is produced by diatoms. Both can lead to severe neurological symptoms.

PSP produced by dinoflaggellates. Domoic acid poisioning produced by diatoms.

Question 28

Protozoans

Protozoans are chemoheterotrophs. What does this mean?

Answer 28

Being chemoheterotrophs, protozoans obtain energy and carbon from organic molecules through chemical processes. They do not perform photosynthesis and rely on external organic sources for their nutrition.

Question 29

Protozoans

Contrast a cyst and a trophozoite life stage of protozoans.

Answer 29

• A cyst is a dormant and protective stage in the life cycle of some protozoans. It enables them to survive harsh conditions and facilitates transmission between hosts.
• In contrast, a trophozoite is the active, growing stage of a protozoan and is responsible for functions such as feeding and reproduction.

Question 30

Helminths

What are the three types of parasitic worms? Know the two names for each group.

Answer 30

1. Trematodes: Flukes
2. Cestodes: Tapeworms
3. Nematodes: Roundworms

Question 31

Helminths

What does monoecious mean?

Answer 31

Monoecious means that one animal has both male and female reproductive organs.

Question 32

Helminths

Which type of parasitic worm is dioecious?

Answer 32

Nematodes (Roundworms) are dioecious, meaning their male reproductive organs are in one individual, and female reproductive organs are in another individual.

Question 33

Helminths

How do cestodes and trematodes absorb nutrients?

Answer 33

Cestodes (Tapeworms) and trematodes (Flukes) absorb nutrients through their cuticles.

Question 34

Helminths

How do nematodes absorb nutrients?

Answer 34

Nematodes (Roundworms) have a complete digestive system for absorbing nutrients.

Question 35

Helminths

What is a scolex?

Answer 35

A scolex is the head of a tapeworm, which typically has suckers or small hooks used for attachment to the host’s intestinal wall.

Question 36

Helminths

What is proglottid?

Answer 36

Proglottids are body segments of tapeworms (cestodes) that contain both male and female reproductive organs. They are continually produced by the neck region of the tapeworm.

Question 37

Helminths

What is a spicule used for? Which type of worm uses a spicule?

Answer 37

• A spicule is used for guiding sperm to the female’s genital pore.
• Nematodes (Roundworms) use spicules.

Question 38

Helminths

Which worm is small, white, and deposits eggs near the anus? What are some of the discomforts that this small, white worm can cause?

Answer 38

• Enterobius vermicularis, also known as the Pinworm, is the small, white worm that deposits eggs near the anus.
• It can cause discomfort, including itching and irritation in the anal area.

Question 39

What is a vector?

Answer 39

• A vector is an organism, often an arthropod like mosquitoes or ticks
• Can carry and transmit pathogenic microorganisms, such as bacteria or parasites, from one host to another.