Chapter 4 Flashcards
1
Q
How are eukaryotic flagella different from bacterial flagella?
A
Thicker, structurally more complex, long sheathed cylinder containing regularly spaced microtubules that is covered by an extension of the cell membrane
2
Q
What are eukaryotic cilia?
A
Similar to the flagella in structure (containing microtubules), but smaller and more numerous
3
Q
Where are cilia found in eukarya?
A
Single group of protozoa and certain animal cells
4
Q
How are microtubules arranged in eukaryotic flagella?
A
Nine pairs regularly spaced extending the length of the flagella surround a single pair
5
Q
What is the eukaryotic glycocalyx?
A
Outermost layer that comes in direct contact with the environment and is composed of polysaccharides
6
Q
How may the glycocalyx be arranged as in eukaryotes?
A
Network of fibers, slime layer, and capsule
7
Q
What does the eukaryotic glycocalyx contribute?
A
Protection, adherence, and signal reception
8
Q
Do protozoa and helminths have cell walls?
A
No
9
Q
What is a prominent feature of cell walls in fungi?
A
Rigid and provide structural support and shape
10
Q
What is the thick inner layer of fungal cell walls composed of?
A
Chitin or cellulose
11
Q
What is the thin outer layer of fungal cell walls composed of?
A
Mixed glycans
12
Q
What is the typical makeup of a eukaryotic cell membrane?
A
Phospholipid bilayer with embedded proteins and sterols
13
Q
What do sterols confer to the eukaryotic cell membrane?
A
Rigidity and stability
14
Q
What are features of the nuclear envelope?
A
Two parallel membranes (lipid bilayers) separated by a narrow space, perforated with small, regularly spaced pores formed at sites where the membranes unite which allow macromolecules to pass to and from the cytoplasm
15
Q
What is the most prominent organelle of eukaryotic cells?
A
Nucleus
16
Q
What is the nucleolus?
A
Site for ribosomal RNA synthesis and collection area for ribosomal subunits found in the nucleoplasm
17
Q
What is chromatin?
A
Genetic material of the cell composed of linear DNA and histone proteins
18
Q
What is the endoplasmic reticulum (includes smooth and rough endoplasmic reticulum)?
A
Series of membrane tunnels used in transport and storage
19
Q
What is the rough endoplasmic reticulum (RER)?
A
Membrane with ribosomes attached (giving rough appearance) that allows the transport of materials from the nucleus to the cytoplasm and the cell’s exterior
20
Q
What is the smooth endoplasmic reticulum (SER)?
A
Closed tubular network without ribosomes that functions in nutrient processing and in synthesis and storage of nonprotein macromolecules such as lipids
21
Q
What is the Golgi body/apparatus?
A
Site consisting of several flattened, disc-shaped sacs call cisternae, where proteins are modified and sent to their final destinations
22
Q
What organelle is the Golgi always associated with?
A
Endoplasmic reticulum
23
Q
How are proteins processed in Golgi?
A
- Transitional vesicles from the endoplasmic reticulum are picked up at the face of the Golgi
- Proteins are modified within the cisternae by the addition of polysaccharides and lipids
- Condensing vesicles pinch off of the Golgi and are then sent to lysosomes or transported out of the cell
24
Q
Describe the steps of assembly of a protein from start to finish
A
- Segment of DNA containing the instructions for producing a protein is copied into RNA
- RNA transcript is passed through the nuclear pores directly to the ribosomes on the endoplasmic reticulum
- Specific proteins produced on the rough endoplasmic reticulum are deposited into the lumen and transported to the Golgi
- Proteins in the Golgi are chemically modified and packaged into vesicles to be used by the cell
25
What are lysosomes?
Bud off the Golgi as a vesicle and contain a variety of enzymes involved in the intracellular digestion of food particles and protection against invading organisms, and participate in the removal of cell debris in damaged tissue
26
What are vacuoles?
Membrane-bound sacs containing fluids or solid particles to be digested, excreted, or stored
27
What cells may vacuoles be found in?
Phagocytic cells, where food and other substances have been engulfed
28
How are contents of a food vacuole digested?
Through merging of a vacuole with a lysosome
29
What are mitochondria?
Energy generators composed of a smooth, continuous outer membrane with an inner folded membrane
30
What are the folds on the inner membrane of mitochondria?
Cristae
31
What is the function of the cristae in mitochondria?
Hold the enzymes and electron carriers of aerobic respiration to extract chemical energy contained in nutrient molecules and store it in the form of high-energy molecules (ATP)
32
How are mitochondria unique organelles?
1. Divide independently of the cell
2. Contain circular strands of DNA
3. Have bacteria-sized 70S ribosomes
33
What is the theory of endosymbiosis?
Mitochondria and chloroplasts in eukaryotes evolved from bacterial cells following an interaction with bacteria and an archaea-like cell
34
What are chloroplasts?
Resemble mitochondria, but are larger, contain special pigments, and are more varied in shape
35
Where are chloroplasts found?
Algae and plant cells
36
What are the capabilities of chloroplasts?
Converting energy from sunlight into chemical energy through photosynthesis, producing oxygen gas as a by-product
37
Where can ribosomes be found in the eukaryotic cell?
1. Scattered freely in the cytoplasm and cytoskeleton
2. Attached to the rough endoplasmic reticulum
3. Inside mitochondria and chloroplasts
38
What are polyribosomes (polysomes)?
Short chains of ribosomes
39
The eukaryotic ribosome is ____ S, composed of a ____ S small and ____ S large subunit
80S; 40S; 60S
40
What are functions of the eukaryotic cytoskeleton?
1. Anchoring organelles
2. Moving RNA and vesicles
3. Permitting shape changes and movement
41
What are the 3 main types of cytoskeleton structures?
1. Actin filaments
2. Intermediate filaments
3. Microtubules
42
What are actin filaments?
Long, thin protein strands
43
What are intermediate filaments?
Ropelike structures
44
What are microtubules?
Long, hollow tubes
45
What are the 3 types of fungal infections in humans?
1. Community-acquired
2. Hospital-associated
3. Opportunistic
46
What is a community-acquired fungal infection?
Caused by environmental pathogens
47
What is a hospital-associated fungal infection?
Caused by fungal pathogens in the clinical setting
48
What is an opportunistic fungal infection?
Caused by low-virulence species infection immunocompromised individuals (AIDS patients)
49
Fungal cell walls give off chemical substances that can trigger what?
Allergies
50
Toxins produced by poisonous mushrooms can induce what?
Neurological disturbances and possibly death
51
What is aflatoxin?
Poison synthesized by Aspergillus flavus that can contaminate grain and be lethal to animals that consume contaminated grain
52
What is the agricultural impact of fungi?
Reduce crop production and can cause disease in domestic animals that consume contaminated crops
53
What are some benefits of fungi?
Important in the decomposition of organic matter, aid plants in absorbing water and nutrients, important in producing antibiotics, alcohol, organic acids, vitamins, food, and flavor
54
All fungi acquire nutrients from a wide variety of organic substances, what is this termed?
Heterotroph (saprobes and parasites)
55
What are saprobes?
Fungi that acquire nutrients from the remnants of dead plants and animals in soil or aquatic habitats
56
Where are parasites (fungi)?
Fungi that grow on the bodies of living animals or plants, although only few require a living host
57
How do fungi acquire nutrients?
Penetrate the substance and secrete enzymes that reduce it to small molecules that can be absorbed
58
Where are fungi often found?
Nutritionally poor or adverse environments, also in environments with high salt or sugar content
59
What do colonies of yeast appear as?
Soft, uniform texture and appearance, like bacteria
60
What do colonies of filamentous fungi (mold) appear as?
Cottony, hairy, fuzzy, velvety texture
61
What is a mycelium?
Woven, intertwining mass of hyphae that makes up the body or colony of a mold
62
What are septa in filamentous fungi?
Solid partitions with no communication between compartments, or partial walls with small pores that allow the flow of organelles and nutrients between adjacent compartments
63
What is nonseptate hyphae?
One long, continuous cell
64
What kind of hyphae produces spores?
Reproductive/fertile
65
What kind of hyphae is responsible for the visible growth that appears on a substrate?
Vegetative
66
What is a notable form of some yeast cells, such as Candida, which is clinically relevant?
Budding
67
What are spores?
Primary reproductive mode of fungi that can be dispersed through the environment by air, water, and living things, and will germinate upon finding a favorable substrate and produce a new fungus colony in a short time
68
Besides spores, how else can filamentous fungi propagate?
Outward growth of existing hyphae or by fragmentation
69
What are sporangiospores?
Spores formed by successive cleavages within a saclike head called a sporangium, that is attached to a stalk called the sporangiophore
70
What are conidia (conidiospores)?
Free spores not enclosed by a spore-bearing sac
71
What is sexual spore formation?
Mixing of DNA from two parent fungi by fusion of fertile hyphae of two different strains or complex union of male and female structures, which may lead to advantageous adaptations
72
What are protozoans?
Single cells containing all major eukaryotic organelles
73
What are the 2 parts of the protozoan cytoplasm?
Ectoplasm and endoplasm
74
What is the ectoplasm?
Clear outer layer involved in locomotion, feeding, and protection
75
What is the endoplasm?
Granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles
76
What may some organelles act as in protozoans?
Primitive nervous system that coordinates movement
77
What are pseudopods?
False feet that can facilitate movement
78
What does the protozoan cell membrane regulate?
Food, wastes, and secretions
79
What is unique about cell shape in protozoans?
Can remain constant (most ciliates) or change constantly (amoebas)
80
What is the size range of protozoans?
Most are 3-300 um, some 3-4 mm
81
Protozoans require food in a complex organic form, therefore they are...
Heterotrophs
82
How do protozoans acquire food?
Some with special feeding structures such as oral grooves or directly through the cell membrane
83
How may pathogenic species acquire nutrients from their host?
From fluids (such as plasma and digestive juices) or actively feed on tissues
84
What is the main limiting factor of protozoans?
Availability of moisture
85
What are the predominant habitats of protozoans?
Fresh and marine water, soil, plants, and animals
86
What is a trophozoite?
Motile feeding stage requiring ample food and moisture to stay alive
87
What is a cyst?
Dormant, resting stage when conditions in the environment become unfavorable, that is resistant to heat, drying, and chemicals, can be dispersed by air currents, and is overall an important factor in the spread of disease
88
Do all protozoan groups have a cyst form?
No, some only exist as trophozoites
89
What is Trichomonas vaginalis?
Common STD (protozoan) that does not form cysts and must be transmitted by intimate contact
90
What is characteristic about Entamoeba histolytica and Giardia lamblia?
Form cysts and readily transmitted in contaminated water and foods
91
How do protozoans reproduce?
Asexual mitotic cell division, multiple fission, or sexual reproductive
92
How do ciliates reproduce?
Sexual reproductive by conjugation where two cells fuse for the exchange of micronuclei, resulting in new genetic combinations that can be advantageous for evolution
93
What does Entamoeba histolytica cause?
Amoebiasis (intestinal and other symptoms)
94
What does Naegleria and Acanthameoba cause?
Brain infection
95
What does Balantidium coli cause?
Balantidiosis (intestinal and other symptoms)
96
What does Giardia lamblia cause?
Giardiasis (intestinal distress)
97
What does Trichomonas vaginalis cause?
Trichomoniasis
98
What does Trypanosoma brucei and Trypanosome cruzi cause?
Trypanosomiasis (intestinal distress and widespread organ damage)
99
What does Leishmania donovani, Leishmania tropica, and Leishmania brasiliensis cause?
Leishmaniasis (either skin lesions or widespread involvement of internal organs)
100
What does Plasmodium vivax, Plasmodium falciparum, and Plasmodium malariae cause?
Malaria (cardiovascular and other symptoms)
101
What does Toxoplasma gondii cause?
Toxoplasmosis (flulike illness or silent infection)
102
What does Cryptosporidium cause?
Cryptosporidiosis (intestinal and other symptoms)
103
What does Cyclospora cayetanensis cause?
Cyclosporiasis (intestinal and other symptoms)
104
Helminths include...
Tapeworms, flukes, and roundworms
105
Are all flatworms and roundworms parasites?
No
106
Where do disease-causing helminths spend part of their lives?
Gastrointestinal tract
107
What is the phylum of flatworms?
Platyhelminthes
108
What are flatworms?
Very thin with an often segmented body plan
109
What are 2 classes flatworms are divide into?
1. Cestodes (tapeworms)
2. Trematodes (flukes)
110
What is the phylum of roundworms?
Aschelminthes
111
What are roundworms also called?
Nematodes
112
What are roundworms?
Elongated, cylindrical, unsegmented body
113
What forms of helminths are easily transmittable?
Eggs and larvae
114
What are helminths?
Multicellular animals that have organs and organ systems
115
What is the most developed organ in pathogenic helminths?
Reproductive tract
116
What are the life cycle stages of helminths?
Fertilized egg, larva, and adult
117
What is the adult helminth's role in its host?
Obtain nutrients from and reproduce sexually
118
What is notable regarding sexes in nematodes?
They are separate and different in appearance
119
What is notable regarding sexes in trematodes?
They can be separate or can have both male and female sex organs
120
What is notable regarding sexes in cestodes?
Generally have both male and female sex organs
121
What occurs in the intermediate (secondary) host with a helminth infection?
Larva develops
122
What occurs in the definitive (final) host with a helminth infection?
Adulthood and mating
123
What is the transport host? Regarding helminth infection
Intermediate that experiences no parasitic development
124
What are sources of human helminth infection?
Contaminated food, soil, water, or infected animals
125
What disease does Ascaris lumbricoides cause?
Ascariasis
126
What disease does Enterobius vermicularis cause?
Enterobiasis/Pinworm
127
What disease does Trichinella spiralis cause?
Trichinellosis
128
What disease does Onchocerca volvulus cause?
Onchocerciasis/River blindness
129
What disease does Dracunculus medinensis cause?
Dracunculiasis
130
What disease does Schistosoma species cause?
Schistosomiasis
131
What disease does Taenia species cause?
Taeniasis/Pork and Beef tapeworm
132
What disease does Diphyllobothrium latum cause?
Diphyllobothriasis/Fish tapeworm
133
What are features of helminth eggs?
Released to environment, have a protective shell and extra food to aid larvae development, and vulnerable to heat, cold, drying, and predators
134
How many eggs can a helminth lay a day?
200k to 25 million
135
Where in the body is there likely to be a pinworm infestation?
Large intestine
136
What is the appearance of pinworm?
2-12 mm long with a tapered, curved cylindrical shape
137
What is the life cycle of pinworm?
1. Microscopic eggs are swallowed by a person after they have been in contact with an infected person or touched contaminated objects
2. Eggs hatch in intestine
3. Larvae mature into adults within 1 month
4. Male and female worms mate
5. Female migrates to the anus and deposits eggs
6. Intense itching
7. Itching/scratching spreads eggs
138
Where is there a higher incidence of helminth diseases?
Tropical areas
139
About how many helminth species cause disease in humans?
50
