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Enzyme structure - Properties of enzymes

By: HWC, Views: 7678

■ Enzymes are proteins that catalyze reactions. ■ Some enzymes have two parts: a protein or apoenzyme and a non-protein or cofactor. ■ Cofactor can be a metal ion or another organic molecule called a coenzyme. ■ Coenzymes often come from vitamins. ■ Cofactors affect the shape of...

Corpus Callosum Animation

By: Administrator, Views: 10583

The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick, nerve tract consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental mammals. It spans part of the longitudinal fissure, con...

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 7298

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...

Metabolic Rate, Heat and Thermoregulation - response to heat and cold stresses

By: HWC, Views: 7940

• A neuron group in the anterior portion of the hypothalamus controls heat balance. • Neurons in the preoptic region of the hypothalamus integrate signals that come from thermoreceptors. • The temperature control center in the preoptic region propagates control signals to two other part...

How proteins function? How do proteins work?

By: HWC, Views: 7382

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...

Introduction to Human Immunodeficiency Virus (HIV)

By: Administrator, Views: 10635

Human immunodeficiency virus gains entry into helper T cells, uses the cell DNA to replicate, interferes with normal function of the T cells, and destroys the normal cells. 1 in 10 persons with AIDS: age 50 or older. 4% of all AIDS cases: age 65 or older. AIDS’ main form of treatment: an...

Urinary System Animation

By: Administrator, Views: 1291

The urinary system: kidneys, ureters, bladder, and urethra with expanded view of a nephron and the urine-filled space within a bladder. Urinary system: two kidneys, two ureters, one bladder, one urethra. Also called the excretory, genitourinary (GU), or urogenital (UG) system. Produces, stor...

Summation - defined, spatial, temporal & AP generation or not

By: HWC, Views: 7646

If several presynaptic end bulbs release their neurotransmitter at about the same time, the combined effect may generate a nerve impulse due to summation Summation may be spatial or temporal • A typical neuron may have thousands of synapses. A corresponding number of postsynaptic membrane ...

Homologous chromosomes during prophase I - Animation

By: HWC, Views: 5597

The chromosomes were duplicated during interphase and the sister chromatids are now in thin threadlike form. Each chromosome becomes zippered to its homologue, so that all four chromatids are closely aligned. The chromosomes are tightly aligned, but we will show them as separate so that y...