CH 5 protists and fungi

Question 1

CH 5

Protist Morphology

Answer 1

Single-celled eukaryotic microorganisms
Cytoplasm divided into two regions
- outer gelatinous region (ectoplasm)
- inner fluid region (endoplasm)
Pellicle (thin layer supporting plasma membrane)
- Carbohydrate layer or glycoprotein layer

Question 2

CH 5

Vacuoles

Answer 2

Located in the cytoplasm
Three classes
- secretory
- contractile
- phagocytic

Question 3

CH 5

Contractile Vacuoles

Answer 3

aid in osmoregulation

remove water from the cell

Question 4

CH 5

Phagocytic Vacuoles

Answer 4

Some protists have specific location for phagocytosis (cytosome)
Undigested materials may be expelled from cell at random locations or at a designated site (cytoproct)

Question 5

CH 5

Cysts

Answer 5

Dormant form of protists
- low metabolic activity
- contained within cell wall
Protect against adverse environmental changes
Serve as a means of transfer between hosts in parasitic protists

Question 6

CH 5

Entamoeba

Answer 6

Internal parasite causing dysentery
Cyst protects the cell from the acid environment of the stomach
Giardia and Cryptosporidium also produce cysts

Question 7

CH 5

Asexual reproduction in protists

Answer 7

Binary Fission
- mitosis followed by cytokenesis
- forming two new, separate organisms
Multiple Fission
- Budding: baby forms and buds off.
--- Ex. Hydra
- Fragmentation: original cell forms multiple cells at once

Question 8

CH 5

Sexual reproduction in protists

Answer 8

Syngamy
Conjugation
They don’t have to deal with periods… rage!!!! … owwwww… T^T

Question 9

CH 5

Syngamy

Answer 9

Fusion of gametes to produce a zygote

• meiosis can occur either before gamete formation or after fusion

Question 10

CH 5

Conjugation

Answer 10

Genetic exchange resulting from fusion of gametic nuclei rather than cells

Question 11

CH 5

Fungi characteristics

Answer 11

Lack chlorophyll
Have absorptive nutrition
Cell wall made of chitin
Vegetative structure is called the thallus
- can be single- or multi-cellular
Reproduce sexually or asexually (most rely more heavily on asexual reproduction, but have both)
Spore bearing

Question 12

CH 5

Yeast v. Mold

Answer 12

Yeasts are all unicellular fungi.

Molds include all multicellular fungi.

Question 13

CH 5

Yeast

Answer 13

Single nucleus
Haploid or diploid (stages of life and reproduction)
Reproduce by budding or binary fission; sexually reproduce by fusion of haploid cells
Can be pathogenic - ex. yeast infection

• happens a lot as people come off antibiotics because your defensive bacteria have also been killed

Question 14

CH 5

Mold

Answer 14

Thallus consists of long, branched filaments of cells called hyphae that mass together to form a mycelium
- hyphae may be septate (divided) or aseptate
Grow from spore > germ tube > hypha > mycellium > thallus

Question 15

CH 5

Fungi asexual reproduction

Answer 15

Binary fission - produces two cells of equal size
Budding - daughter cell is smaller than mother cell
Asexual reproduction is often accompanied by asexual spore formation for dispersal

Question 16

CH 5

Spore types

Answer 16

We classify fungi based on spore formation:
Athroconidia
Sporagiospores
Conidiospores
Blastospores

Question 17

CH 5

Fungi sexual reproduction

Answer 17

Involves fusion of compatible nuclei

• Homothallic - from same mycellium; self-fertilizing
• Heterothallic - from different mycellium May have fusion of cells or hyphae
• sometimes nuclei fuse immediately, but often there is a dikaryotic stage where the cytoplasmic fusion is finished by the nuclear fusion is still ongoing

Question 18

CH 5

Diploid/ haploid fungi cycle

Answer 18

Diploid stage > meiosis > haploid stage > cytoplasmic fusion > dikaryotic stage > nucleic fusion > zygote > diploid stage
Usually environmental cues trigger the shifts between these stages.

Question 19

CH 5

Fungal spores

Answer 19

Not as durable as endospores, which are meant mainly for survival - fungal spores are mainly for dispersal.
Spore coat enables spores to survive environmental stresses:
- dessication
- limited nutrients
- temperature fluctuation