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Cellular slime mold life cycle Animation

By: HWC, Views: 1958

Life cycle of Dictyostelium discoideum, a cellular slime mold Animation. Amoeba-like slime mold cells live in the soil, where they feed on bacteria. The free-living cells grow and reproduce by mitosis. When food dwindles, the amoebas stream toward one another in response to a chemical...

Ciliate conjugation Animation

By: HWC, Views: 2109

Protozoan conjugation is an unusual form of sexual reproduction Prospective partners join together, usually at the surface of their oral depressions. The cells undergo cytoplasmic fusion. Meiosis II produces four haploid micronuclei. Now the macronucleus of each cell begins to bre...

Red alga life cycle Animation

By: HWC, Views: 1917

Life cycle of Porphyra. The most conspicuous part of this algal life cycle is the haploid gametophyte. This sheetlike form is collected and dried for use as nori, the wrapping for sushi. Gametes form in packets interspersed between vegetative cells near the sheet margins. The gamet...

Body plan of euglena Animation

By: HWC, Views: 2044

Euglenoids are single-celled organisms that live in lakes and ponds. A contractile vacuole pumps out the water that diffuses into the cell from its hypotonic surroundings. The body is covered by a translucent pellicle composed of flexible strips of a protein-rich material. Light passe...

The Krebs Cycle Animation

By: HWC, Views: 1926

The second-stage reactions of aerobic respiration. The second-stage reactions occur in a mitochondrion's inner compartment. In the first preparatory reaction, a carbon atom is stripped from pyruvate and released as carbon dioxide. The remaining carbons combine with coenzyme A and give ...

Alternative Energy Sources

By: HWC, Views: 1966

Points at which organic compounds enter the reaction stages of aerobic respiration. Complex carbohydrates are broken down into simple sugars, such as glucose. They become the substrates for glycolysis. If your body doesn't need to burn glucose for energy, glucose-6-phosphate can be co...

Fermentation pathways

By: HWC, Views: 1661

Both lactate fermentation and alcoholic fermentation begin with pyruvate formed by glycolysis. During lactate fermentation, pyruvate molecules accept electrons and hydrogen from NADH. This transfer regenerates NAD± and converts pyruvate to lactate. The net energy yield is the two ATP...

Condensation and Hydrolysis Animation

By: HWC, Views: 1558

A condensation reaction joins two molecules together to form one larger molecule. An enzyme removes a hydroxyl group from one molecule and a hydrogen atom from another, then speeds the formation of a bond between the two molecules at their exposed sites. Typically the discarded atoms join t...

Secondary and tertiary levels of protein structure Animation

By: HWC, Views: 1632

Amino acid sequence dictates a protein's final shape. The presence of certain amino acids favors a pattern of hydrogen bonding that causes part of the polypeptide chain to coil and twist into an alpha helix. The presence of other amino acids enables hydrogen bonding between strand like re...