Chapter 5.4 APBIO

What are the functions of proteins(8)

Enzymatic(digestive),Defensive,storage,transport,hormonal,receptor,movement,structural support.

Proteins are all constructed form the same set of ____ amino acids, the bond between amino acids is called a___ ____so a polymer of an amino acid is called a ______

20,peptide bond,polypeptide

A protein is a biologically functional molecule made up of one or more _____, each folded and coiled into a specific three-dimensional structure.

polypepetides

What are the five parts of amino acids?

At the center of the amino acid is an asymmetric carbon atom called the alpha α carbon. Its four different partners are an amino group, a carboxyl group, a hydrogen atom, and a variable group symbolized by R.

The R group, also called the ___ _____, differs with each amino acid.What is the range in complexity from simplarity for the different varieties of r groups?

side chain. 1  Hydrogen atom to a carbon skeleton w/ various functional groups

he physical and chemical properties of the side chain ______ the unique characteristics of a particular amino acid

Determine

Acidic amino acids have side chains that are generally ______ in charge due to the presence of a carboxyl group

Negative

When two amino acids are positioned so that the ______ group of one is adjacent to the amino(NH2) group of the other, they can become joined by a dehydration reaction, with the removal of a water molecule

Carboxyl(COOH)

In almost every case, the function of a protein depends on its ability to recognize and ___ to some other molecule.

Bind

proteins share three superimposed levels of structure, known as primary structure, secondary structure, and tertiary structure. A fourth level, quaternary structure, arises when a protein consists of ____ or more polypeptide chains.

two

PrThe primary structure of a protein is its sequence of ____ ____

Amino acids

How many different amino acids are there?

20

Primary structure is like the ___ of ___ in very long word

order of letters

The precise primary structure of a protein is determined no by the random linking of amino acids, but by ____ _____ _______.

Inherited genetic information.

The primary structure dictates secondary and tertiary structure due to the chemical nature of the ____ and the ___ ____ of amino acids along the polypeptide.

Backbone, side chain.

What is secondary structure

When segments of protein’s polypeptide chains repeatedly coiled or folded in patterns that contribute to the protein’s overall shape.

The coils and folds are the result of ___ ___ between the repeating constituents of the polypeptide BACKBONE(NOT THE SIDE CHAINS).

hydrogen bonds

why do hydrogen bonds form in the secondary structure?

In the backbone, the oxygen atoms have a partial negative charge and the hydrogen atoms have a partial positive charge.

If Hydrogen bonds are weak, how can they support a particular shape for that part of the protein?

Individually they are weak, but because they are repeated many times over a long region of the polypeptide chain, they are strong.

Name the two secondary structures

Alpha helix and beta pleated sheet

What is the alpha helix

A delicate coil held together by hydrogen bonding between every fourth amino acid.

What is the beta pleated sheet

Two or more segments of the polypeptide chain lying side by side(called beta strands) are connected by hydrogen bonds bewteen parts of the two parallel segments. beta pleated sheets make up the core of many proteins.

What is tertiary structure?

The overall shape of a polypeptide resulting from interactions between the side chains of the amino acids.

Name 4 interactions that help fold the polypetides

Hydrophobic interaction,van DER Waals interactions, hydrogen bonds, and disulfide bridges

What is a hydrophobic interaction?

When amino acids with hydrophobic side chains end up in clusters at the core of he protein, out of contact with the water.

When do disulfide bridges form/what are they?

Where two cysteine monomers (which have sulfhydryl groups on the side chains)are brought close together by the folding of the protein. the sulfur of one cysteine bonds to the sulfur of the second, and the disulfide bridge rivets parts of the protein together.

Some proteins consist of two or more polypeptide chains aggregated into one functional macromolecule. what is the overall protein structure that results from the aggregation of these polypeptide subunits?

Quatrenary structure

What functional groups are in carbs?

hydroxyl

carbonyl

What functional groups are in proteins?

amino

carboxyl

r groups: hydroxyl

sulfhydril

carbobyl

methyl

What functional groups are in lipids?

carboxyl-on fatty cids

hydroxyl-glycerol

sometimes phosphate

What functional groups are in nucleic acids?

phosphate(backbone)

hydroxyl(on the sugar)

amino(in the nitrogenous bases)

Even a ___ change in primary structure can affect a protein’s shape and ability to function

small

To sum it up, what are the key factors determining protein structure?

A polypeptide chain of a given amino acid sequence can be arranged into a three-dimensional shape determined by the interactions responsible for secondary and tertiary structure.other proteins also aid in folding.

denaturation

In proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive

When a protein in a test-tube solution has been denatured by heat or chemicals, it can sometimes return to its functional shape when the _____ ___ is removed

denaturing agent

Is it easy to correlate the primary structure of many proteins with their three-dimensional structure to discover the rules of protein folding?

NO

is Misfolding of polypeptides in cells a serious problem?

YEs

The method most commonly used to determine the 3-D structure of a protein is_ ___ ________

X-ray crystallography