05: A Survey of Eurkaryotic Cells and Microorganisms

Question 1

Eukaryotic Microbes

Answer 1

Question 2

Eukaryotic Cell

Answer 2

Question 3

Organization of Eukaryotic Cell

Answer 3

• Eukaryotic cell
  
  • External structures
  • Boundary of cell
  • Organelles and other components within the cell membrane
• External structures
  
  • Glycocaly
    
    • Capsules
    • Slimes
• Boundary of cell
  
  • Cell wall
  • Cell/ cytoplasmic membrane

Question 4

Flagella

Answer 4

• Locomotor Appendages
• Long, sheathed cylinder containing microtubules in a 9+2 arrangement
• Covered by an extension of the cell membrane
• 10× thicker than prokaryotic flagella

Question 5

Cilia

Answer 5

• Locomotor Appendages
• Similar in overall structure to flagella, but shorter and more numerous
• Found only on a single group of protozoa and certain animal cells
• Function in motility, feeding, and filtering

Question 6

Glycocalyx

Answer 6

• An outermost boundary that comes into direct contact with environment
• Usually composed of polysaccharides
• Appears as a network of fibers, a slime layer or a capsule
• Functions in adherence, protection, and signal reception
• Beneath the glycocalyx
  
  • Fungi and most algae have a thick, rigid cell wall
  • Protozoa, a few algae, and all animal cells lack a cell wall and have only a membrane

Question 7

Which part of the Eukaryotic cell is responsible for contacting the outside environment and signaling between cells?

A. Flagella

B. Cell Wall

C. Glycocalyx

D. Cell Membrane

Answer 7

C. Glycocalyx

Question 8

Functions of Internal Structures within the Eukaryotic Cell

Answer 8

Question 9

Rough Endoplasmic Reticulum

Answer 9

• originates from the outer membrane of the nuclear envelope
• extends in a continuous network through cytoplasm
• rough due to ribosomes
• proteins synthesized and shunted into the ER for packaging and transport
• first step in secretory pathway

Question 10

Smooth Endoplasmic Reticulum

Answer 10

• closed tubular network without ribosomes
• functions in nutrient processing, synthesis, and storage of lipids

Question 11

Golgi Apparatus

Answer 11

• Modifies, stores and packages protiens
• Consists of a stack of flattened sacs called cisternae

Question 12

Lysosomes

Answer 12

• Synthesis and transport machine
• Vesicles containing enzymes that originate from Golgi apparatus
  
  • intercellular digestion of food particles
  • protection against invading microbes

Question 13

Vacuoles

Answer 13

• Synthesis and transport machine
• Membrane bound sacs containing particles
  
  • digested
  • excreted
  • stored

Question 14

Phagosomes

Answer 14

• Synthesis and transport machine
• Vacuoles merged with a lysosome

Question 15

Mitochondria

Answer 15

• Function in energy production and storage (ATP)
• Cristae
  
  • Spherical organelle with an outer membrane and an inner membrane with folds
• Cristae membranes
  
  • hold the enzymes and electron carriers of aerobic respiration
• Divide independently of cell
• Matrix
  
  • DNA and prokaryotic ribosomes are contained in the spaces around the cristae

Question 16

Chloroplasts

Answer 16

• Convert the energy of sunlight into chemical energy through photosynthesis
• Found in algae and plant cells
• Thylakoids
  
  • Outer membrane covers inner membrane folded into sacs stacked into grana.
  • Carry pigments (chlorophyll and others)
• Primary producers of organic nutrients for other organisms

Question 17

The Eukaryotic organelle that is responsible for transporting vesicles inside the cells is the

A. Golgi

B. Smooth Endoplasmic Reticulum

C. Rough Endoplasmic Reticulum

D. Nucleus

Answer 17

A. Golgi

Question 18

Kingdom Fungi

Answer 18

• Majority are unicellular or colonial
• few have cellular specialization
• 100,000 species divided into 2 groups:
  
  • Macroscopic fungi (mushrooms, puffballs, gill fungi)
  • Microscopic fungi, with two morphologies
    
    • Hyphae – long filamentous fungi or molds
    • Yeast – round ovoid shape, asexual reproduction

Question 19

Hyphae

Answer 19

• Long, threadlike cells that make up the bodies of filamentous fungi, or molds
• Some present various textures of mycelia
• Array of color differences macroscopically due to spores

Question 20

Yeasts

Answer 20

• Cell distinguished by
  
  • round to oval shape
  • mode of asexual reproduction
• Presents a cell wall
• lacks locomotor organelles
• It grows swellings on its surface called buds
  
  • which then become separate cells

Question 21

Yeasts

Answer 21

• Some form a pseudohypha, a chain of yeasts formed when buds remain attached in a row
• Because of its manner of formation, it is not a true hypha like that of molds

Question 22

Filamentous Fungi (molds)

Answer 22

• cottony, hairy, or velvety texture
• Woven intertwining mass of hyphae called mycelium;
• may be divided by cross walls (septa)
  
  • Vegetative hyphae – digest and absorb nutrients
  • Reproductive hyphae – produce spores for reproduction

Question 23

Sporangiospores

Answer 23

• Asexual Spore Formation
• Sporangium
  
  • formed by successive cleavages within a saclike head
• Spores initially enclosed but released when the sporangium ruptures.

Question 24

Conidiospores (conidia)

Answer 24

• Asexual Spore Formation
• Free spores not enclosed by a spore-bearing sac

Question 25

Sexual Spore Formation

Answer 25

• Spores are formed following fusion of two different strains and formation of sexual structure
  
  • Zygospores
  • ascospores
  • basidiospores
• Sexual spores and spore-forming structures are one basis for classification

Question 26

Fungal Classification

Kingdom Eumycote

Answer 26

• subdivided into several phyla based upon the type of sexual reproduction:
  
  • Phylum Zygomycota
    
    • zygospores; mostly sporangiospores and some conidia
  • Phylum Ascomycota
    
    • ascospores; conidia
  • Phylum Basidiomycota
    
    • basidiospores; conidia
  • Phylum Chytridomycota
    
    • flagellated spores (Effects frogs)
  • Fungi that produce only Asexual Spores (Imperfect)

Question 27

Phylum I

Zygomycota

Answer 27

• Sexual spores: zygospores
• Asexual spores: mostly sporangiospores, some conidia
• Hyphae are usually nonseptate. If septate, the septa are complete
• Most species are free-living saprobes; some are animal parasites
• Can be obnoxious contaminants in the laboratory, food spoilage agents, and destructive to crops
• Examples of common molds:
  
  • Rhizopus, a black bread mold
  • Mucor
  • Absidia
  • Circinella

Question 28

Phylum II

Ascomycota

Answer 28

• Sexual spores: most produce ascospores in asci
• Asexual spores: many types of conidia, formed at the tips of conidiophores
• Hyphae with porous septa
• By far the largest phylum.
  
  • Macroscopic mushrooms to microscopic molds
  • yeasts

Question 29

Phylum II

Ascomycota Examples

Answer 29

• Penicillium: one source of antibiotics
• Aspergillus: common airborne mold that may be involved in respiratory infections and toxicity
• Candida pseudohyphae: yeast used in making bread and beer
• Pneumocystis (carinii) jiroveci: pathogen of AIDS patients
• Histoplasma: cause of Ohio Valley fever
• Trichophyton: cause of ringworm
• Coccidioides immitis: cause of Valley fever;
• Candida albicans: cause of various yeast infections
• Stachybotrys: toxic mold

Question 30

Phylum III

Basidiomycota

Answer 30

• Many members are familiar macroscopic forms
  
  • mushrooms and puffballs
• number of microscopic plant pathogens
  
  • rusts and smuts
    
    • attack and destroy major crops

Question 31

Phylum IV

Chytridimycota

Answer 31

• Members of this phylum are unusual, primitive fungi commonly called chytrids.
• cellular morphology ranges
• single cells to clusters and colonies
• They generally do not form hyphae or yeast-type cells
• presence of special flagellated spores
  
  • zoospores and gametes.
• Most chytrids are saprobic and free-living in soil, water, and decaying matter.
• Not known to cause human disease
• Known to be serious frog pathogens

Question 32

Roles of Fungi

Adverse Impact

Answer 32

• Mycoses
• allergies
• toxin production
• Destruction of crops and food storages

Question 33

Roles of Fungi

Beneficial Impact

Answer 33

• Sources of antibiotics
• alcohol
• organic acids
• vitamins
• Decomposers of dead plants and animals
• Used in making foods
• genetic studies

Question 34

Fungi are generally classified according to their

A. Type of sexual spore

B. Type of asexual spore

C. Type of hyphae

D. Type of habitat

Answer 34

C. Type of hyphae

Question 35

Algae

Answer 35

• eukaryotic organisms
• usually unicellular and colonial
• photosynthesize with chlorophyll

Question 36

Protozoa

Answer 36

• unicellular eukaryotes
• lack tissues
• share similarities
  
  • cell structure
  • nutrition
  • life cycle
  • biochemistry

Question 37

Algae

Answer 37

• Photosynthetic organisms
• Microscopic forms are unicellular, colonial, filamentous
• Macroscopic forms are colonial and multicellular
• Contain chloroplasts with chlorophyll and other pigments
• Cell wall
• May or may not have flagella
• Most are free-living in fresh and marine water – plankton
• Provide basis of food web in most aquatic habitats
• Produce large proportion of atmospheric O2
• Dinoflagellates can cause red tides and give off toxins that cause food poisoning with neurological symptoms

Question 38

Protozoa

Answer 38

• Diverse group of 65,000 species
• Vary in shape, lack a cell wall
• Most are unicellular; colonies are rare
• Most are harmless, free–living in a moist habitat
• Some are animal parasites and can be spread by insect vectors
• All are heterotrophic–lack chloroplasts
• Cytoplasm divided into ectoplasm and endoplasm
• Feed by engulfing other microbes and organic matter
• Most have locomotor structures–flagella, cilia, or pseudopods
• Exist as trophozoite–motile feeding stage
• Many enter a dormant stage during unfavorable conditions for growth and feeding–cyst
• All reproduce asexually, mitosis or multiple fission; many also reproduce sexually– conjugation

Question 39

Pathogenic flagellates:

Trypanosomes

Answer 39

• Genus Trypanosoma
  
  • T. brucei – African sleeping sickness
  • T. cruzi – Chaga’s disease
• Long, crescent-shaped cells with a single flagellum
• Occur in the blood during infection
• Transmitted by blood-sucking vectors

Question 40

Infective amoebas:

Entamoeba

Answer 40

• Entamoeba histolytica – amebic dysentery
• Ingested cysts germinate in the small intestine
• Trophozoites migrate to the large intestine and grow
• They can invade the liver, lungs, and skin
• Common symptoms include gastrointestinal disturbances

Question 41

Parasitic Helminths

Answer 41

• Multicellular animals, organs for reproduction, digestion, movement, protection
• Parasitize host tissues
• Have mouthparts for attachment to or digestion of host tissues
• Most have well-developed sex organs that produce eggs and sperm
• Fertilized eggs go through larval period in or out of host body

Question 42

Flatworms

Answer 42

• flat, no definite body cavity
• digestive tract a blind pouch
• simple excretory and nervous systems
  
  • Cestodes (tapeworms)
  • Trematodes or flukes
    
    • flattened, nonsegmented worms with sucking mouthparts

Question 43

Roundworms (nematodes)

Answer 43

• round
• complete digestive tract
• protective surface cuticle
• spines and hooks on mouth
• excretory and nervous systems poorly developed

Question 44

Parasitic helminths reproduce by:

A. Cysts

B. Spores

C. Eggs and sperm

D. All of the above

Answer 44

C. Eggs and sperm