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64 Cards in this Set
- Front
- Back
When were the first eukaryotic cells on earth?
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Approx 2 billion years ago
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Symbiosis
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Eukaryotic organelles originated from prokaryotic cells trapped inside of them
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T/F: Animals have no cell wall.
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True
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Characteristics of a cell wall
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rigid
provide structure & shape different chemically from prokaryotic cell walls. |
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Cytoplasmic Membrane
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Bilayer of phospholipids with protein molecules embedded
Defines interior from exterior |
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Why is it important that the cytoplasmic membrane is selectively permeable?
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Can't let everything in. What's the point of having a membrane.
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The nucleus is the _________ _____ of the cell.
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control center
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Where is the nucleolus and what happens there?
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In the nucleus and performs rRNA synthesis.
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The chromatin in the nucleus is ________ and ________.
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open and unwound
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Ribosomes
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Protein Synthesizers
Some scattered in the cytoplasm and cytoskeleton. Others associated with RER. Composed of large and small subunits of ribonucleoprotein. |
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What is the cytoskeleton?
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Provides structure, moving structures inside cell, and moving cell
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Microfilaments
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Thin protein strands.
Some active in amoeboid motion. Ex: Actin |
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Microtubules
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Biggest of three filaments inside cell.
Long, hollow tubes. Maintains shape & transports substances. |
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Macroscopic fungi
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see with the naked eye
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Microscopic fungi
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Need a microscope to see.
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Yeasts
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Round oval shape
Unique mode of asexual reproduction |
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Hyphae
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Long, threadlike cells
Some are dimorphic (2 shapes) Fig 5.15 |
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Fungal Nutrition:
Saprobes |
like decaying matter
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Fungi's general method of obtaining nutrition:
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Penetrates the substrate
Secretes enzymes Breaks down the enzymes into small molecules |
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Mycelium
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the woven, intertwining mass of hyphae that makes up the body or colony of a mold. Single-cell strand
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Vegetative hyphae (mycelia)
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normal life cycle of fungus
Fig 5.18 |
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Reproductive (fertile) hyphae
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responsible for the production of spores. These spores are not as resistant as bacterial endospore.
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Reproductive Strategies and Spore Formation of Fungi
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-propagate by growth of hyphae or fragmentation (hyphae breaks off and keeps growing)
- 1' reproductive mode is production of spores (large diversity of spores) |
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Sexual spores of Fungi
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Can be sexual or asexual. They have lots of options
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One reason fungi specimens are hard to grow and identify is because:
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they need to be isolated on special types of media
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One common way to identify fungi
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Usually use sexual spore-forming structures and spores
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Other characteristics that contribute to identification of fungi
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Hyphal type
Colony texture and pigmentation Physiological characteristics Genetic makeup |
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T/F: Fungi are not capable of photosynthesis.
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True
They do not contain chlorophyl |
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Do fungi need a host to live?
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NO, nearly all are free-living.
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How do humans become infected with a pathogenic fungi?
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Usually occurs through accidental contact of compromised immune system.
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Other than infections, what are fungi involved in?
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Allergies, poisoning, agricultural damage.
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Benefits of fungi:
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Decomposing organic matter and returning essential minerals to the soil
Helps plants absorb water and nutrients |
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Fungi is used in the production of:
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Antibiotics
Alcohol Organic acids Vitamins |
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Two major taxonomic categories of The Protists
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Subkingdom Algae
Subkingdom Protozoa |
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General definition of Protists
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Any unicellular or colonial organism that lacks true tissues
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How many species of protozoa are there?
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~ 65,000
Most are harmless, few are parasites |
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Form & Function of Protozoa
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-most are single cells
-contain major organelles -cytoplasm divided -some ciliate and flagellates working like primitive nervous system **no cell wall |
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Ectoplasm of protozoa
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clear outer layer involved in locomotion, feeding, and protection
cytoplasm |
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Endoplasm of protozoa
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granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles
cytoplasm |
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Protozoa nutrition
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-heterotrophic (don't photosynthsis)
-require food in complex organic form (take off chunks of stuff) -scavengers -parasitic species can live on fluids or tissues of hosts |
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Protozoa Habitat
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Fresh and marine water
Soil Plants Animals |
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Styles of locomotion for protozoa
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pseudopods, flagella, or cilia
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Pseudopods
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Amoeboid motion
Can serve as feeding structures |
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Flagella
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From one to several
Some attached along the length of the cell by the undulating membrane |
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Cilia
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Mostly distributed over the entire surface of the cell
Form characteristic patterns |
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Life cycles of protozoa
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Some exist only in trophozoite stage (active stage).
Others alternate between trophozoite and cyst (although not protozoa form cysts) |
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Reproduction of protozoa
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-Ciliates participate in conjugation. -They just come up against each other, no pilis.
-Can do asexual, some do sexual. |
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What is classification of protozoa based on?
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Method of Motility
Method of Reproduction Stages in life cycle |
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Mastigophora
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Motility primarily by flagella
Single nucleus Most form cysts and are free-living Most are solitary |
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Sarcodina
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Amoebas
Pseudopods Asexual reproduction by fission (split) Mostly uninucleate Usually form cysts Most free-living |
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Ciliophora
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Ciliated
Trophozoites mobile by cilia Some have cilia in tufts for feeding and attachment Most develop cysts Show relatively advanced behavior (communication) Majority are free-living and harmless |
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Apicomplexa
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Sporozoa
Complex life cycles Important in transmission of infections Entire group is parasitic |
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Protozoan Identification and Cultivation
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Shape and size of cell
Number of nuclei Can be cultivated on artificial media or in laboratory animals |
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Pathogenic Flagellates
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Trypanosomes
neurological pathogens ex: Chagas diseases |
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Infective Amoebas
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Entamoeba
Fourth most common protozoan infection in the world AKA: amoebic dysentery |
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The Parasitic Helminths
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Two major groups: Flatworms and Roundworms
Adults large enough to be seen with the naked eye |
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Flatworms
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Thin
Often segmented "good parasites"- they don't kill hosts |
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proglotid
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section of flatworm that is full of eggs
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Roundworms
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Unsegmented worms
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General Worm Morphology
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-Most organs are those of the reproductive tract.
-Fundamental digestive, excretory, nervous and muscular systems. -Have thick cuticles- can withstand digestive acids. |
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Nematodes
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Separate sexes
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Trematodes
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separated sexes or hermaphoditic
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What is an intermediate (Secondary) host for worms?
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Usually where larval development occurs. Example would be pigs before it gets to humans.
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Helminth Classification and Identification
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Shape
Size Degree of development of various organs Presence of hooks, suckers, or other special structures Mode of reproduction Kinds of hosts Appearance of eggs and larvae |