Search results for: 'types of mutation'

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By: HWC, Views: 4265

A mutation, which may arise during replication and/or recombination, is a permanent change in the nucleotide sequence of DNA. Damaged DNA can be mutated either by substitution, deletion or insertion of base pairs. Mutations, for the most part, are harmless except when they lead to cell death or t...

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Chronology of leptin research (A history of leptin research)

By: HWC, Views: 4811

In 1950. researchers at Jackson Laboratories noticed that one of their mice had become extremely obese—it had an insatiable appetite. Intrigued, they bred a strain of mice showing this characteristic. In the late 1960s, researchers surgically connected the bloodstreams of a normal mouse and a...

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Bond types - Atomic structure and basis of bonds

By: HWC, Views: 8120

• Chemical bonds are fundamental to the structure and function of many types of molecules, such as proteins, carbohydrates, lipids, nucleic acids, gases, salts and water. ■ These molecules are composed of atoms that are held together by three different types of bonds. • The three types ...

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Bone tissue types - compact and spongy

By: HWC, Views: 7818

Bone tissue types • There are two types of bone tissue: compact and spongy. • All the bones of the skeleton have both kinds of bone tissue. • Compact (dense) bone • Arranged in osteons (Haversian systems), units of lamellae laid down in adjoining series of concentric rings. • P...

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Metaphase I Animation

By: HWC, Views: 5778

This is a cell during metaphase I. For each pair of chromosomes, any gamete produced by this cell could contain either the maternal chromosome or the paternal chromosome. How many different combinations of maternal and paternal chromosomes are possible in the gametes produced by a cell with th...

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Types of disease resistance: innate defenses & immunity

By: HWC, Views: 7977

Our immune system protects us and helps fight off disease. Microorganisms, small microscopic organisms, and viruses are everywhere. Ever thought about how many are on that door you just opened? Many microbes and viruses can cause disease and are termed pathogens. Plants and animals have what i...

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Muscular System Animation

By: Administrator, Views: 10646

Three basic types of muscles: - Skeletal - Smooth - Cardiac Composed of striated or smooth muscle tissue and classified according to their functions and appearance. Skeletal Muscle: - Also known as voluntary or striated muscle. - Controlled by the conscious part of the brain and attach...

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Types of synapses - electrical & chemical

By: HWC, Views: 7841

• Neurons communicate with one another or effector cells via synapses that allow information to be filtered and integrated. • The two types of synapses are: • electrical • chemical. • Electrical synapses, also known as gap junctions, contain many ion channels (connexons) conne...

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Neuron Structure Animation

By: Administrator, Views: 11089

There are several types of neurons, three of which are: Motor neurons, Sensory neurons, Interneurons. The nervous system is usually described as having two interconnected divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). CNS: Includes the brain and spinal...

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