Search results for: 'Photosynthetic bacteria'

Watch Later 1:01

Chronology of leptin research (A history of leptin research)

By: HWC, Views: 4805

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...

Watch Later 1:24

Endocytosis -Types and Phagocytosis

By: HWC, Views: 7770

Endocytosis is the process by which a substance is brought inside a cell without having to pass through the cell membrane. It is the opposite of endocytosis, the process by which substances exit the cell without having to pass through the cell membrane. Exocytosis – membrane-enclosed secret...

Watch Later 1:12

Griffith's experiments

By: HWC, Views: 4878

In the late 1920s, Fred Griffith was attempting to develop a vaccine against a bacterium that causes pneumonia. To find out why two strains of the bacteria differed in their deadliness, he injected mice with four different mixtures. Mice injected with R cells remained healthy. When Griffith ex...

Watch Later 1:27

Causes of Acne

By: Administrator, Views: 10801

Short video on the causes of acne.

Watch Later 2:31

The Pressure Flow Model in a Plant

By: HWC, Views: 7118

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...

Watch Later 3:45

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

By: HWC, Views: 8038

• 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. �...

Watch Later 1:05

Hershey Chase Experiments

By: HWC, Views: 4901

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. ...

Watch Later 0:57

Cellular slime mold life cycle Animation

By: HWC, Views: 1970

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...

Watch Later 1:35

Transferring genes into plants Animation

By: HWC, Views: 5097

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...

Search Results