Proteins Flashcards
are by far the most important of all biological compounds.
Proteins
The main structural material for plants is cellulose.
For animals, it is structural proteins, which are the chief constituents of skin, bones, hair, and nails.
Structure
Two important structural proteins are
collagen and keratin
Virtually all the reactions that take place in living organisms
Catalysis
Every time we crook a finger, climb stairs, or blink an eye, we use our muscles.
Movement
A large number of proteins perform transportation duties.
Transport
Many hormones are proteins, including insulin, erythropoletin, and human growth hormone.
Hormones
are fat-soluble molecules made from cholesterol.
Steroid hormones
these are the three major sex hormones groups:
estrogens, androgens and progesterones.
Some proteins store materials in the way that starch and glycogen store energy.
Storage
Some proteins not only control the expression of genes, thereby regulating the kind of proteins synthesized in a particular cell, but also dictate when such manufacture takes place.
Regulation
which are insoluble in water and are used mainly for structural purposes
fibrous proteins
which are more or less soluble in water and are used mainly for nonstructural purposes.
globular proteins
is an organic compound containing an amino group and a carboxyl group.
amino acid
A pH at which a sample of amino acids or protein has an equal number of positive and negative charges.
Isoelectric point (pl)
Compounds that have a positive charge on one atom and a negative charge on another are called
zwitterions
zwitterions, from the German word
zwitter
zwitterions, from the German word zwitter, meaning?
hybrid
The very word “protein” is derived from the Greek
proteios
The very word “protein” is derived from the Greek proteios, meaning?
of first importance
the amino acid is still an lon, so it is still soluble in water. There is no pH at which an amino acid has no lonic character at all. If the amino acid is a positive ion at low pH and a negative lon at high pH, there must be some pH at which all the molecules have equal positive and negative charges. This pH is called the
isoelectric point (pt)
can in turn be fairly easily reduced to give two molecules of cysteine.
cystine
the presence of cystine has important consequences for the chemical structure and shape of the protein molecules of which it is part. The bond is also called a
disulfide bond
Tryptophan is converted to serotonin, more properly called
5-hydroxytryptamine