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Components of the Nervous System

By: Administrator, Views: 392

The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue...

DNA Replication Factory and Protein

By: HWC, Views: 6150

DNA (deoxyribose nucleic acid) carries all the genetic information needed to re-create itself and to pass on the characteristics of the organism. The “factory” model of DNA replication hypothesizes a specific nuclear structure in which the molecular machinery for replication forks are brou...

Molecules, Membrane Permeability and Structure

By: HWC, Views: 6168

Organisms are not isolated system at equilibrium and need to intake nutrients and electrolytes as remove wastes. Similarly Cells within an organism must also exchange compound by passing them through membrane. The permeability of a membrane is the rate of passive diffusion of molecules th...

Polysaccharides

By: HWC, Views: 6224

More complex sugars are called polysaccharides (from "poly" meaning "many" and "saccharum" meaning "sugar"). Many things in nature are made of polysaccharides. Here we show one of the polysaccharides in corn, another in wood, and another in the exoskeletons of insects like grasshoppers. How are a...

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

By: HWC, Views: 5965

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...

Subunits of DNA And Semi Conservative Replication

By: HWC, Views: 3063

Adenine is a purine with a double-ring structure. In double-stranded DNA, adenine base-pairs with thymine. Guanine is a purine with a double-ring structure. In double-stranded DNA, guanine base-pairs with cytosine. Thymine is a pyrimidine with a single-ring structure. In double-stranded DNA, th...

Types of disease resistance: innate defenses & immunity

By: HWC, Views: 6868

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...

Interspecific Competition Relationship - Competitive & Niche Differentiation

By: HWC, Views: 6327

In an environment with limited resources, any organisms that utilize the same resources will be in competition with each other. For example, let's look at two competing species of paramecium, a single-celled organism that feeds on bacteria. If we raise each of these species in isolation, both...

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

By: HWC, Views: 6306

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 ...