Monday February 1, 1999
Announcements: Review Session tonight at 110 Wartick Lab, from 6:30-7:30

Lecture notes:

Prokaryotes: (no nucleus) divide by binary fission. One piece of DNA divides, there are no organelles to separate.

Mitosis: the mechanism by which eukaryotic cells of the new generation receive a duplicate of the parental DNA.

Cytokinesis: dividing up of the cytoplasm. This happens in late anaphase or telophase.

Chromosomes: pieces of DNA with attached DNA proteins. A cell of a species can have as many as 1,000. Usually that are 10-50.

Sister Chromatids: duplicated DNA.

Centromere: the area where sister chromatids are attached.

Condensed chromosome: a chromosome which has coiled itself into a compact unit prior to separation of sister chromatids. (mitosis/meiosis).

Kinetochores: Chromosomal proteins that form on the sides of each centromere. They become attached to microtubules that help move chromosomes during the nuclear division processes (mitosis/meiosis).

Interphase has 3 parts: G₁ a period of growth and synthesis of new cell parts.
S "sythesis" phases - the DNA replicates
G₂ preparation for mitosis

Mitosis: divided into 4 phases

Prophase: 1. Condensation of chromatin into visible sister chromatids with centromeres.
2. Nucleolus disassembles.
3. Microtubules disassemble and create spindles.
4. Centrioles, if present, separate and go to poles.

Metaphase: 1. Nuclear envelope has disintegrated.
2. Chromatids line up at the equator of the cell with sister chromatids at right angles to the spindle.

Anaphase: 1. Sister chromatids separate.
2. Each chromatid is pulled toward the "poles" by spindle microtubules attached to the kinetochore on each
centromere.

Telophase: 1. The spindle apparatus disappears.
2. Chromosomes "decondense"
3. Nuclear envelope reappears.

Cytokinesis devides up the cytoplasm and make two new cells. It occurs during late anaphase and throughout telophase.

In "protists" and in animals, remnants of part of the spindle apparatus contracts to form a "cleavage furrow". This continues to contract until two cells are formed.

In plants a "line" is drawn at the equator, cellulose and other membrane and cell wall parts are deposited until the "cell plate" is complete.

Monera: 1. All are prokaryotes (with no true nucleus or organelles)
2. All are single celled.
3. Some are autotrophs. *
4. Some are heterotrophs. **

Includes: Eubacteria: true bacteria (Cyanobacteria - blue-green algae - belong to this class)
Archaebacteria

Protista: 1. Mostly single celled, some multicelled.
2. Includes both autotrophs and heterotrophs.
3. Cells are eukaryotic.
4. Some are photosynthetic.

Includes: golden algae, diatoms, amoeba, ciliates.

Fungi: 1. Almost all are multicelled.
2. All are heterotrophs.
3. Most are "extracellular digestion".
4. All are eukaryotic.
5. None are photosynthetic.

Includes: yeast, mushrooms, toadstools.

Plantae: 1. Almost all are multicelled.
2. All are autotrophs.
3. All are eukaryotic.
4. All are photosynthetic.
5. Some obtain "energy" from other sources in addition to photosynthesis.

Includes: mosses, ferns, flowering plants, trees

Amalia: 1. All are multicelled.
2. All are heterotrophic.
3. All are eukaryotic.
4. None are photosynthetic.

Includes: sponges, worms, insects, fishes, reptiles, birds, mammals

* Autotrophs: Self-feeder-An organism that obtains carbon and all metabolic energy from organic molecules that have already been assembled by autotrophs.

** Heterotroph: "Other" feeder-An organism that obtains carbon and all metabolic energy from organic molecules that have already been assembled by autotrophs.

1. Complex structural organization based on instructions contained in DNA molecules.
2. Directly or indirectly, dependence on other organisms for energy and material resources.
3. Metabolic activity by the single or multiple cells composing their body.
4. Use of homeostatic controls that maintain favorable operating conditions in the body despite changing conditions in the environment.
5. Reproductive capacity, by which the instructions for heritable traits are passed from parents to offspring.
6. Diversity in their form, in the functions of their various body parts, and in their behavior. Such traits are adaptations to changing conditions on the environment.
7. The capacity to evolve, based ultimately on variations in traits that arise through mutations in their DNA.