3.12-3.14 Flashcards
Nearly every dynamic function in your body depends on ______
protein.
Define protein:
a polymer made of amino acids. They are structurally and functionally the most complicated.
What is the most important role of proteins in your body?
Enzymes: the chemical catalyst that speed and regulate virtually all chemical reactions in you cells. Ex. lactase
What are transport proteins?
embedded in cell membranes, they move sugar molecules and other nutrients into cells.
What are defensive proteins?
Located in the blood stream. Antibodies of the immune system.
What are signal proteins?
hormones and chemical messengers that help coordinate your body’s activities.
What are receptor proteins?
receive and transmit the signals of signal proteins into cells.
What are contractile proteins?
responsible for the contracting of muscle fibers.
What are (broad) structural proteins?
Found in fibers that make up tendons and ligaments. Ex. collagen. Forms the long and strong fibers of connective tissue. 40% of protein in body.
What are storage proteins?
supply amino acids to developing embryos. Proteins found it eggs and seeds.
What does function depend on?
form/shape.
What is an example of a globular protein?
lysozyme. Most enzymes are globular.
What is an example of a fibrous protein?
silk. because of its construction, it is stronger than steel.
Where are fibrous proteins usually found?
Structural proteins: hair, tendons, ligaments.
What are the shapes in proteins?
globular, fibrous.
The diagrams of shape of lysozyme protein appear random (pg. 43), but…
the represent the molecules, specific, three dimensional, shape. Lysozyme destroys bacterial cells, but it can only bond to them because of a groove its structure has.
What part does sulfur play in proteins?
it can form stabilizing bonds.
Define denaturation:
a process in which a protein unravels and loses its shape and therefore its function. Heat can do this. Ex. when an egg is fried, structural proteins surrounding the yolk become white instead of clear.
What are the harmful effects of denaturation?
When amino acids lack shape, it can lead to Alzheimer’s and Parkinson’s. Prions are infectious misshapen proteins, and cause degenerative diseases.
Why does a denatured protein no longer function normally?
The function of each protein is a consequence of its specific shape, which is lost when a protein is denatured.
What are amino acids made of?
An amino groups and a carboxyl group (making it an acid), which are both covalently bonded to a carbon. This carbon is bonded to a hydrogen, and an “R” which represents a single molecule or chain that could be attached to the molecule, and determine which type of amino acid it is.
What is the most simple amino acid?
Glycine: r is just a hydrogen.
What does R look like, if not glycine?
one or more carbon atoms with various functional groups attached.
_____ can be hydrophobic or hydrophilic (polar or nonpolar), or charged.
R groups.
How does pH play into how charged an amino acid is?
it is “charged” at the pH of a cell. (don’t know the math for this)
If we look back at functional group table, amino and carboxyl groups can be ionized. In proteins, what are they, and the central carbon, ionized by?
the cellular pH.
How are proteins joined?
Dehydration synthesis. Amino group of a protein is bonded to the carboxyl group of another.
What is the link between amino acids called?
A peptide bond (covalent). Dipeptide, polypeptide, etc.
How many bonds to polypeptides have?
100-1000+. Each with a unique sequence of amino acids.
What does the R- group influence the most?
The 3D structure of the protein
What do hydrophobic amino acids behave like?
may cluster together in the center of a globular protein.
What do hydrophilic amino acids behave like?
may face the outside of a globular protein and help proteins dissolve in the aqueous solutions of a cell. They can also form hydrogen and ionic bonds which influence structure. Disulfide bridges.
What is the primary structure of a protein?
the precise sequence of amino acids in a polypeptide chain. A straight line connecting all the individual amino acids.
What is the secondary structure of a protein?
When segments of the primary structure fold into local patterns. Ex. a pleated sheet pattern.
What are secondary structures maintained by?
hydrogen bonds between atoms of the polypeptide backbone.
What is the tertiary structure of a protein?
overall three dimensional shape of a protein (multiple local patterns, probably). This is where the hydrophobic and hydrophilic amino acids are separated into inside and outside, etc.
What is the quaternary structure, if applicable, of a protein?
Proteins with more than one polypeptide chain. They are identical in the example.
