Search results for: 'HWC'

Watch Later 1:37

By: HWC, Views: 7042

A short, radiolabeled primer is annealed to the single-stranded DNA to be sequenced. The DNA serves as a template for in vitro DNA synthesis. The DNA-primer mixture is split into four separate tubes. DNA polymerase and a solution of dNTPs are added to each tube. One of the four 2',3' dideoxy-N...

Watch Later 2:23

Hierarchical Sequencing Method - Sequence Tagged Sites

By: HWC, Views: 6962

In the hierarchical sequencing method, researchers begin by collecting cells. In humans, each cell contains 23 pairs of chromo-somes. Here we specifically track the DNA from just one of the 23 pairs. Chromosomes have a series of unique DNA sequences, called sequence-tagged sites (STSs), that a...

Watch Later 3:10

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 7181

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Watch Later 2:36

Phases of an Action Potential - Resting Potential, Threshold, Rising, Falling, & Recovery Phases

By: HWC, Views: 7141

In this tutorial, we will review the phases of an action potential measured from a small area of a neuron's membrane. The action potential can be divided into five phases: the resting potential, threshold, the rising phase, the falling phase, and the recovery phase. When the neuron is at rest,...

Watch Later 1:42

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 7002

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

Watch Later 2:10

Power Supply Polyacrylamide Gel Protein Sample

By: HWC, Views: 7081

SDS-polyacrylamide gel electrophoresis is a powerful tool, which resolves proteins according to their molecular weights. Because proteins differ in size, shape, and charge, a protein sample is first denatured with the anionic detergent SDS. When the sample is heated, the SDS molecules bind to ...

Watch Later 3:20

SNP Polymorphysim Microarray Chip - How to Test a Person's DNA

By: HWC, Views: 7026

To test a person's DNA, a researcher first needs a source of tissue. Most of the cells in a blood sample are red blood cells, which lack nuclei, but there are also a number of white blood cells, which do contain nuclei and chromosomal DNA. If we could see a particular DNA sequence in these cel...

Watch Later 3:08

The Hypothalamus: The Body's Thermostat (Human Thermostat)

By: HWC, Views: 6957

Normal body function requires a relatively constant body temperature, which is regulated by the body's thermostat, a region of the brain called the hypothalamus. The hypothalamus generates a temperature set point for the body and appears to be the major site for the integration of temperature inf...

Watch Later 1:22

How Hemoglobin Picks Up and Delivers Oxygen

By: HWC, Views: 7027

All of the cells in our bodies require oxygen (02) for survival and must release carbon dioxide (CO2) as a waste product. The respiratory and circulatory systems work together as delivery systems for these gases. The lungs exchange these gases between the environment and the bloodstream. The bloo...

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