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Stages of Mitosis - Prophase, Prometaphase, Metaphase, Anaphase & Telophase

By: HWC, Views: 7426

In mitosis, the nucleus divides to produce two nuclei that are genetically identical to each other and to the parent nucleus. To prepare for division, the DNA replicates in the preceding interphase. Although the chromosomes are not yet compacted and visible as discrete bodies, we illustrate them ...

X chromosome inactivation in calico cats

By: HWC, Views: 4674

X chromosome inactivation causes a mosaic tissue effect in calico cats. what makes this female calico cat "calico." Like all mammals, this cat began her life as a single cell. That cell had two X chromosomes, one from each parent. One of the chromosomes carried a dominant allele for the ...

Contraction cycle of a sarcomere

By: HWC, Views: 8178

• A single nervous signal releases Ca2+ ions into the sarcoplasm and initiates the contraction cycle. step 1. ATP hydrolysis • ATP provides the to move myosin molecules back into the energized configuration necessary to perform the power stroke. Step 2. Crossbridge attachment • Myosin...

Frequency of stimulation and force (Recruitment of motor units and force)

By: HWC, Views: 8043

• Muscle tension depends on the frequency of stimulation. • Muscle twitch: First stimulus. • Wave summation: When a second stimulus excites a partially relaxed muscle, producing a stronger contraction. • Unfused tetanus: Successive stimulations at the same frequency, producing a se...

Studying the Left and Right Brain Independently

By: Administrator, Views: 10976

A seizure, technically known as an epileptic seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with loss of consciousness (tonic-clonic seizure), to shakin...

Global warming and its effect on climate change

By: HWC, Views: 7304

Global warming, habitat destruction, and pollution are all hot topics in the news. Environmentalists are concerned that many of these factors will lead to the loss of species. But how will this happen? One way to think about the environment is as a finely-tuned, high performance engine. If one...

Stretch reflex & Tendon reflex

By: HWC, Views: 7428

• The stretch reflex is a response to the stretching of muscles. It is monosynaptic and ipsilateral. • Stretching stimulates receptors in the muscle spindle of the agonist (stretched) muscle. • One or more action potentials are generated by the receptors and propagate along the axon of ...

Major Elements in Biological Molecules: Lipids

By: HWC, Views: 7045

A triglyceride (also called triacylglycerol) is composed of three fatty acid molecules and one glycerol molecule. The fatty acids attach to the glycerol molecule by a covalent ester bond. The long hydrocarbon chain of each fatty acid makes the triglyceride molecule nonpolar and hydrophobic. Pa...

How do the different types of chromatography work? (No Audio)

By: HWC, Views: 7046

Chromatography is a term for a variety of techniques in which a mixture of dissolved components is fractionated as it moves through some type of porous matrix. A glass column is filled with beads of an inert matrix. The mixture of proteins to be purified is dissolved in a solution and passed ...