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Cellular slime mold life cycle Animation

By: HWC, Views: 1960

Life cycle of Dictyostelium discoideum, a cellular slime mold Animation. Amoeba-like slime mold cells live in the soil, where they feed on bacteria. The free-living cells grow and reproduce by mitosis. When food dwindles, the amoebas stream toward one another in response to a chemical...

Hershey Chase Experiments

By: HWC, Views: 4886

Hershey and Chase knew that T4 bacteriophages consist of proteins and DNA. They asked which viral component must enter a bacterial cell to infect it: DNA or protein? They grew viruses with either radioactive sulfur, which labels the viral protein, or radioactive phosphorus, which labels DNA. ...

Barriers - eye structures, digestive mucosa, respiratory mucosa & genitourinary mucosa

By: HWC, Views: 8016

• Eyebrows, eyelids, eyelashes and conjunctiva serve to trap microbes preventing their invasion. • Tearing (lacrimation) is a protective mechanism that washes away microbes that attempt to enter the eyes. • Salts, mucus, and lysozymes in tears neutralize substances and bacteria. â€...

Chronology of leptin research (A history of leptin research)

By: HWC, Views: 4790

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...

Origin of organelles Animation

By: HWC, Views: 1365

Possible origins of the nucleus and other organelles. Some prokaryotic cells have infoldings of their plasma membrane. These infoldings may have served as channels from the cytoplasm to the cell surface. These membranous folds may have evolved into the endoplasmic reticulum and the nuclear e...

Transferring genes into plants Animation

By: HWC, Views: 5079

Researchers extract DNA from an organism that has a trait they want to introduce into a plant. The genetic donor can be a bacterial cell, a plant cell. or even an animal cell. The desired gene will be transferred into a plasmid, a small circle of bacterial DNA. The gene is cut out of th...

B cells and antibodies

By: HWC, Views: 8513

What Are Antibodies? Antibodies, also known as immunoglobulins, are Y-shaped proteins that are produced by the immune system to help stop intruders from harming the body. When an intruder enters the body, the immune system springs into action. These invaders, which are called antigens, can be vi...

Causes of Acne

By: Administrator, Views: 10788

Short video on the causes of acne.

Inflammation and Fever

By: HWC, Views: 8216

• Inflammation is an immune response that can occur anywhere in the body, but is observed most frequently on the skin. • It provides early protection by preventing infection from spreading to other parts of the body. • Inflammation also promotes repair of damaged tissues. Inflammat...