Chapter 3 Biology (proteins)

What are proteins that act as organic catalysts to accelerate chemical reactions within cells?

enzymes

What is keratin an example of?

fibrous protein

What are structural proteins with helices and/or pleated sheets that hydrogen bond to one another?

fibrous proteins

What type of protein makes up hair and nails? What basic role does it do?

keratin; support

What structure results when two or more polypeptides combine?

quaternary structure

What structure results when a polypeptide coils or folds in a particular way?

secondary structure

Up to how many levels of structure can proteins have?

4

What was the second pattern discovered (shows secondary structure)

beta sheet 1) Pleated beta sheet polypeptides turn back upon themselves. 2) Hydrogen bonding occurs between extended lengths.

What type of protein fibers support many of the body's structures (e.g., ligaments, tendons, skin)? What basic role does it do?

collagen fibers; support

How many different amino acids are commonly found in cells?

20

What makes amino acids differ from one another?

R group (range from a single hydrogen to complicated ring compounds)

What two things do amino acids contain?

acidic group and amino group

What was the first pattern discovered? (shows secondary structure)

alpha helix 1) In a peptide bond, oxygen is partially negative, hydrogen is partially positive. 2) This allows for hydrogen bonding between the C=O of one amino acid and the N—H of another. 3) Hydrogen bonding between every fourth amino acid holds the spiral shape of an alpha helix

How do proteins play a role in defense?

functions include antibodies that prevent infection

What tend to ball up in a rounded shape in the tertiary structure?

globular proteins

What is an example of a globular protein with a quaternary structure of four polypeptides? (each polypeptide has a primary, secondary, and tertiary structure)

hemoglobin

What are regulatory proteins that influence the metabolism of cells?

hormones

What does the polarity of the peptide bond permit?

hydrogen bonding between different amino acids in a polypeptide.

In what two ways do proteins assist in transportation?

include channel and carrier proteins in the plasma membrane and hemoglobin that transports oxygen in red blood cells

What hormone regulates glucose content of blood and within cells?

insulin

What gives rise to the 3-D shape in the tertiary structure?

interactions among the R groups of the constituent amino acids

Is oxygen or nitrogen more electronegative?

oxygen (electrons are more attracted to oxygen than nitrogen)

What is two or more amino acids bonded together called?

peptide

What is a covalent bond between two amino acids?

peptide bond

What are chains of many amino acids joined by peptide bonds?

polypeptides

What structure is the protein's particular sequence of amino acids?

primary structure

What helps to maintain the tertiary structure?

strong disulfide linkages (also hydrogen, ionic, and covalent bonds)

What are the 6 basic functions of proteins?

support, enzymes, transport, defense, hormones, motion

What structure results when proteins are folded, giving rise to the final three-dimentional shape of the protein?

tertiary structure

What protein sequence did Frederick Sanger discover?

the hormone insulin

What determine the function of a protein?

the protein shape

Do atoms of a peptide bond share electrons evenly or unevenly?

unevenly

Can a protein contain more than one polypeptide? What does this mean?

yes; the protein can have a very large number of amino acids