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Proteins Defined, Hierarchy & Composition of Cells

By: HWC, Views: 7836

Proteins are long chains of amino acids linked together by peptide bonds. Together with the other three biological macromolecules—carbohydrates, lipids, and nucleic acids—proteins are the building blocks of cells. Proteins are the most complex and abundant biological macromolecules in cel...

How proteins function? How do proteins work?

By: HWC, Views: 8016

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...

Structure of Amino Acid, Peptide Bonds & Polypeptides

By: HWC, Views: 7853

Here are the molecular formulas of three different amino acids. All amino acids share this backbone. The main difference between every amino acid is the side groups seen here, and these side groups give each of the amino acids their different characteristics. But before we get into that, let's ...

Protein Structure - Primary, Secondary, Tertiary and Quaternary

By: HWC, Views: 8276

A protein's first order structure, or primary structure, begins with the amino acid sequence of the polypeptide chain. The 20 different amino acids can be arranged in an infinite number of sequences. For example, the hormone insulin, which regulates the uptake of glucose from the blood into ce...

Mitochondrial Structure & ETC Protein Complexes (Protein Complexes and Electron Transport)

By: HWC, Views: 7976

The energy carrying molecules, NADH and FADH2, that were generated in glycolysis and the Krebs cycle, now are processed in the mitochondria where their high energy electrons are deposited in an electron chain complex located in the inner mitochondrial membranes. These high-energy electrons now dr...

ETC Protein Complexes & Chemiosmosis (Total ATP Production and ATP Synthase)

By: HWC, Views: 8048

You will notice that FADH2 donates two electrons further downstream than NADH. This results in only two protons being pumped across the inner membrane. The final electron acceptor for these transported electrons is oxygen. Oxygen receives these electrons, plus protons from the aqueous matrix. ...

Diversity of Living Creatures - Charles Darwin & the Beagle's Voyage

By: HWC, Views: 8053

As we look around at the living creatures on Earth, we see a great amount of diversity. In some cases, the differences are quite noticeable, like the differences between plants and animals. Some differences are not as easy to see, like the differences between two species of lizard. How did all...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 8224

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

Natural Selection, Species Isolation and Real World Example

By: HWC, Views: 7812

`Natural selection' is the process in which organisms with adaptive traits survive and breed in greater number than organisms without such traits. Eventually, almost all of the individuals in the population will have the same adaptive trait. This was the concept presented by Charles Darwin in ...