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Results for: 'brownish-black pigment melanin'

X chromosome inactivation in calico cats

By: HWC, Views: 1167

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 ...

What are Strong & Weak Acids and How they're different?

By: HWC, Views: 3363

Let's consider the changes that take place when hydrogen chloride, HCI, is added to water. You will need to recognize space-filling models of HCI molecules, hydronium ions (H30+), chloride ions (C11, and water molecules (H20). They are shown at the right. When HC1 molecules dissolve in water, ...

Introduction to Macular Degeneration

By: Administrator, Views: 7239

Macular degeneration An incurable, age-related, progressive eye disease that affects more than 10 million Americans. Leading cause of blindness for those ages 55 and older. Macular degeneration For the first time, researchers have linked gene defects to macular degeneration. Could lead to ...

Optic Nerve and Optic Disk Animation (Part 1 of 2)

By: Administrator, Views: 7163

Inner Layer Blind spot: the absence of rods and cones in the area of the optic disk creates a blind spot on the retina's surface; the only part of the retina that is insensitive to light. Inner Layer The eye contains approximately 120 million rods that are sensitive to dim light. The rods ...

What are the Parts of a Plant Cell?

By: HWC, Views: 3447

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...


By: Administrator, Views: 7372

Eye Composed of special anatomical structures that work together to facilitate sight: Cornea Pupil Lens Vitreous body Light stimulates sensory receptors (rods and cones) in the retina or innermost layer of the eye. Vision is made possible through the coordinated actions of nerves that co...

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

By: HWC, Views: 3916

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...

Electromagnetic Spectrum, Chlorophyll and Pigment & Light

By: HWC, Views: 3904

The sun gives off radiation that is called the electromagnetic spectrum. This is energy that travels as wavelengths and includes radio waves, X-rays and ultraviolet light. A portion of this radiation is known as visible light, and is the type of radiation that plants use to manufacture sugars. ...


By: Administrator, Views: 7207

A cataract is a clouding of the lens in the eye which leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and trouble seeing at night. This may re...