The Evolution of Eukaryotes: Flashcards
What is a pellicle?
a thick, outer covering of the cell. This covering is outside the plasma membrane.
(Pellicle is elastic and gives Euglena particular swimming characteristics.)
What is multiple fission?
- It is the splitting of one cell into multiple (more than two) cells
- (It is an asexual reproductive process)
What is budding?
It refers to the outgrowth of a new cell from the surface of an old one
- (It is an asexual reproductive process)
- Still doing Mitosis (identical clones of parents)
What are psuedopods?
also know as false feet, psuedopods are extensions of the cytoplasm that are used for locomotion and feeding.
-They move in a blobby way b/c cytoskeleton proteins.
what are aveoli?
- It is a sac under an Alveolates plasma membrane
- Which may play a role in supporting the cell surface.
what is red tide?
results from an overpopulation of toxic dinoflagellates.
what is conjugation?
- in conjugation, bacteria cells form a “mating bridge” between the two cells and genetic information passes from one cell to the other.
- two individuals line up tightly against each other and fuse in the oral groove region of the body.
What is the basic idea behind the Endosymbiotic Theory?
- Lynn Margulis in 1966
- The theory purposes that certain organelles are the descendants of prokaryotes engulfed, but not digested, by ancient eukaryotic cells.
What, historically, was the purpose of the taxon Kingdom Protista?
is a formal taxonomic group, a convenience term for, “all the eukaryotes that are not plants, animals, or fungi.”
Within that kingdom, what was the major criterion for determining the phylum to which a protistan species belonged?
n
What are characteristics of eukaryotic cells that distinguish them from prokaryotic cells?
membrane-bound organelles and nucleus
Which organelle do biologist believed evolved first: the mitochondrion or the chloroplast? Why do they think that is true?
mitochondrion
What are the four typical cell surfaces of protists?
- Plasma membrane:
- cell walls:
- Pellicle:
- Shells/tests:
For protists that have macronuclei, what is the function of the macronucleus?
to regulate the life o the cell
What is the function of the micronucleus?
- Is essential for genetic recombination.
- (its a typical eukaryotic nuclei)
What is the role of the micronucleus during conjugation?
The role of the micronuclei is to form macronuclei through a series of dramatic chromosomal rearrangements.
Is conjugation a sexual reproduction? why or why not?
Conjugation is a sexual process, but is not a reproductive one.
What is autotrophic?
can produce its own food
What is heterotrophic?
relies on some other source of carbon for it to make energy.
What are protists?
They are Eukaryotes that are not plant, animal, or fungi.
When did Eukaryotes come about?
About 1.5 BYA
Photosynthesis arose approximately how long ago?
2.8 BYA
What are some other Eukaryotic innovations?
- flexible surface (high surface~volume)
- Cytoskeleton
- Digestive vacuoles
- Chloroplast / Mitochondria
What are the important events that were involved in the origin of the modern eukaryotic cell?
- The origin of a flexible cell surface
- The origin of a cytoskeleton
- The origin of a nuclear envelope, which enclosed a genome organized into chromosomes
- The appearance of digestive vacuoles
- The acquisition of certain organelles via endosymbiosis
All alveolates are:
-unicellular
The cell wall of the protists main component is?
cellulose
-Cell wall is outside the plasma membrane
What’s the benefit to an organism for its cells to have high surface area-to-volume ratios?
More efficient diffusion at cellular level
Primary way to classify protists?
By their method of locomotion:
- flagella
- cillia
- pseudopods
Bacteria does not have DNA kept in the nucleus, where do they keep their genetic material?
In the Nucleoid, (not all bacteria have capsules)
Flexible surface in Eukarytoes are for what?
Allows high surface are to volume ratio= more space
Habitats for Protists:
- Aquatic (marine or freshwater)
- body fluids of hosts
- damp soils
- feces (giardia)
–ALL ARE FOUND NEAR MOISTURE!!!
Protists Reproduction:
Asexual
- Binary fission
- budding
- spores
What are spores?
- Specialized cell that can grow into a new individual
- emerge from capsulates
Which organelle is responsible for digestion of cell nutrients/food?
Lysosome
Describe the Eukarytoic innovation of the Cytoskeleton?
-Its important functions include: Providing cellular shape Internal movement of organelles -micro-filaments -intermediate filaments -microtubules: (Cillia and flagella)
Modes of nutrition for Protists:
- Autotrophs: requires photosynthetic pigments to absorb energy
- Heterotrophs: getting food source/nutrients from outside source
- SOME ARE BOTH AUTOTROPHIC && HETEROTROPHIC!!!!!
The Former “kingdom Protista”:
- Alveolates
- Stramenophiles
- Rhizaria
- Excavates
- Amoebozoans
