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How does an animal choose what food to eat?

By: HWC, Views: 7182

One might assume that natural selection has influenced the foraging behaviors of animals, and that most animals forage efficiently, spending the least energy to gain the most nutrients. This is the underlying assumption of optimality modeling, a scientific approach to studying foraging behavior. ...

Parkinson's Disease

By: Administrator, Views: 11708

Parkinson's disease (PD) is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. As the disease worsens, non-motor symptoms become increasingly common. The symptoms generally come on slowly over time. Early in the disease, the most obvious are shak...

Protein catabolism (Krebs cycle) and Protein anabolism (protein synthesis)

By: HWC, Views: 8173

• Deaminated acids are brought into the Krebs cycle to be oxidized to CO2 and H2O. • Before entering the Krebs cycle, the deaminated acids are converted into intermediate products (pyruvic acid, acetyl coenzyme A, carbonic acids). • In the Krebs cycle, amino acids are oxidized to form r...

Hypoglycemia Animation

By: Administrator, Views: 11870

Hypoglycemia, also known as low blood sugar, is when blood sugar decreases to below normal levels. This may result in a variety of symptoms including clumsiness, trouble talking, confusion, loss of consciousness, seizures or death. A feeling of hunger, sweating, shakiness and weakness may also be...

The Pressure Flow Model in a Plant

By: HWC, Views: 7103

The vascular system of plants has two transport tissues, called xylem and phloem. Xylem transports water and minerals, while phloem transports a variety of dissolved substances, including sugars and amino acids, throughout the plant. Water in the xylem always moves up, in the direction from th...

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

By: HWC, Views: 7299

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...

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

By: HWC, Views: 7027

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...

Replication of DNA and Chromosomes/ How do cells replicate their DNA? (Animation) no Audio

By: HWC, Views: 7463

DNA replication in E. coil begins at a site called oriC where a replication bubble forms. At either end of this bubble is a replication fork. Since DNA polymerase Ill can read its DNA template strand only in the 3' to 5' direction this means that one strand (leading) can be read continuously b...

Spermatogenesis Animation

By: Administrator, Views: 11077

Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. T...