Show Advanced Search

REFINE YOUR SEARCH:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by journal section

Filter by science education

 
 
Glycine: A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.

What are Proteins?

JoVE 10677

Proteins are chains of amino acids that are connected by peptide bonds and folded into a 3-dimensional structure. The side chains of individual amino acid residues determine the interactions among amino acid residues, and ultimately the folding of the protein. Depending on the length and structural complexity, chains of amino acid residues are classified as oligopeptides, polypeptides, or proteins. An amino acid is a molecule that contains a carboxyl (–COOH) and an amino group (–NH2) attached to the same carbon atom, the ⍺-carbon. The identity of the amino acid is determined by its side chain or side residue, often called the R-group. The simplest amino acid is glycine, where the residue is a single hydrogen atom. Other amino acids carry more complex side chains. The side chain determines the chemical properties of the amino acid. For example, it may attract or repel water (hydrophilic or hydrophobic), carry a negative charge (acidic), or form hydrogen bonds (polar). Of all known amino acids, only 21 are used to create proteins in eukaryotes (the genetic code encodes only 20 of these). Amino acids are abbreviated using a three letter (e.g., Gly, Val, Pro) or one letter code (e.g., G, V, P). The linear chain of amino acid residues forms the backbone of the protein. The free amino group at one end is called the N-terminus, while t

 Core: Biology

Responses to Salt Stress

JoVE 11120

Salt stress—which can be triggered by high salt concentrations in a plant’s environment—can significantly affect plant growth and crop production by influencing photosynthesis and the absorption of water and nutrients.

Plant cell cytoplasm has a high solute concentration, which causes water to flow from the soil into the plant due to osmosis. However, excess salt in the surrounding soil increases the soil solute concentration, reducing the plant’s ability to take up water. High levels of sodium are toxic to plants, so increasing their sodium content to compensate is not a viable option. However, many plants can respond to moderate salt stress by increasing internal levels of solutes that are well-tolerated at high concentrations—like proline and glycine. The resulting increased solute concentration within the cell cytoplasm allows the roots to increase water uptake from the soil without taking in toxic levels of sodium. Sodium is not essential for most plants, and excess sodium affects the absorption of essential nutrients. For example, the uptake of potassium—which regulates photosynthesis, protein synthesis, and other essential plant functions—is impeded by sodium in highly saline conditions. Calcium can ameliorate some effects of salt stress by facilitating potassium uptake through the regulation of ion

 Core: Biology

Electrospinning of Silk Biomaterials

JoVE 5798

Silk fibers have been processed and used to create fabrics and threads for centuries. However, the solubilizing of silk fibers, thereby turning it into a versatile pre-polymer solution is a much newer technology. Solubilized silk can be processed in many different ways to create a biocompatible material with controllable mechanical properties.


 Bioengineering

Chromatin Immunoprecipitation

JoVE 5551

Histones are proteins that help organize DNA in eukaryotic nuclei by serving as “scaffolds” around which DNA can be wrapped, forming a complex called “chromatin”. These proteins can be modified through the addition of chemical groups, and these changes affect gene expression. Researchers use a technique called chromatin immunoprecipitation (ChIP) to …

 Genetics

Dendrimer-based Uneven Nanopatterns to Locally Control Surface Adhesiveness: A Method to Direct Chondrogenic Differentiation

1Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 2Department of Engineering Electronics, University of Barcelona (UB), 3Networking Biomedical Research Center (CIBER), 4Instituto de Investigacin Biomédica de Málaga (IBIMA), Department of Organic Chemistry, Universidad de Málaga (UMA), 5Andalusian Centre for Nanomedicine and Biotechnology-BIONAND, 6Unidad de Bioingeniería Tisular y Terapia Celular (GBTTC-CHUAC), Grupo de Reumatolog ía, Instituto de Investigación Biomèdica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, Universidade da Coruña (UDC), 7Institució Catalana de Recerca i Estudis Avançats (ICREA), 8Instituto de Investigación Biomédica de Málaga (IBIMA), Department of Cell Biology, Genetics and Physiology, Universidad de Málaga (UMA)

JoVE 56347

 Bioengineering
12345678955
More Results...