Search results for: 'muscle cell'

Watch Later 0:42

By: HWC, Views: 6114

Formation of membrane attack complexes. Complement proteins can activate when they bind to antibodies that are bound to a pathogen. Complement proteins also activate when they bind directly to bacterial surfaces. Cascading reactions yield huge numbers of different types of complement protei...

Watch Later 1:29

Fertilization and Development

By: HWC, Views: 9666

• Fertilization is the process by which the two gametes from the parents fuse their genetic material to form a new individual (zygote). • Fertilization requires that sperm cells swimming through the uterine tube contact a secondary oocyte. • Once sperm penetrate the secondary oocyte's ...

Watch Later 2:54

Mutations and translation

By: HWC, Views: 5895

A mutation, which may arise during replication and/or recombination, is a permanent change in the nucleotide sequence of DNA. Damaged DNA can be mutated either by substitution, deletion or insertion of base pairs. Mutations, for the most part, are harmless except when they lead to cell death or t...

Watch Later 1:03

Mechanism of enzyme action

By: HWC, Views: 9130

■ The substrate makes contact with the active site. ■ A change in the shape of the enzyme occurs resulting in the transformation of the substrate. ■ A substrate may undergo decomposition, have its atoms rearranged, or two substrates may be synthesized. ■ The products of the reaction...

Watch Later 0:22

Osmosis - water transport

By: HWC, Views: 9474

Osmosis is the flow of water down its concentration gradient, across a semi-permeable membrane. Osmosis is an example of diffusion, which is when molecules tend to distribute themselves evenly in a space. what is a semi-permeable membrane? It is a membrane or barrier that allows some molec...

Watch Later 1:05

Second Stage of Labor and Delivery

By: Administrator, Views: 599

During labor forceful contractions move the fetus down the birth canal and expel it from the uterus. Signs and symptoms that labor is about to start can occur from hours to weeks before the actual onset of labor. Braxton Hicks contractions Irregular contractions that begin in the second trim...

Watch Later 1:38

First Stage of Labor and Delivery Video

By: Administrator, Views: 12490

During labor forceful contractions move the fetus down the birth canal and expel it from the uterus. Signs and symptoms that labor is about to start can occur from hours to weeks before the actual onset of labor. Braxton Hicks contractions Irregular contractions that begin in the second trim...

Watch Later 2:35

Pores and Ion Channels

By: HWC, Views: 8481

Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix. Membrane po...

Watch Later 1:43

Polysaccharides

By: HWC, Views: 8989

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...

Search Results