Protein Structure and Function

Play an AI-generated podcast conversation about this lesson

What can form a diffusion barrier similar to the nuclear pore?

A network of polypeptide chains with disulfide bonds

A dense network of unstructured proteins (correct)

A network of hexagonally packed globular protein subunits

A dense network of structured proteins

What type of bonds form between adjacent cysteine side chains?

Covalent disulfide bonds (correct)

Hydrogen bonds

Peptide bonds

Ionic bonds

What is a common feature of protein assemblies?

Multiple protein-protein contacts (correct)

Multiple protein-ligand contacts

Multiple protein-nucleic acid contacts

Multiple protein-membrane contacts

What is the shape of the protein coat or capsid of many simple viruses?

A hollow sphere based on an icosahedron Signup and view all the answers

What is the function of the capsid in viral structures?

To enclose and protect the viral nucleic acid Signup and view all the answers

What is a characteristic of protein subunits in viral capsids?

They are composed of identical protein molecules Signup and view all the answers

What is the approximate diameter of the tomato bushy stunt virus (TBSV)?

33 nm Signup and view all the answers

How many identical copies of the capsid protein are present in the TBSV?

180 Signup and view all the answers

What is the purpose of the proteolytic enzyme in insulin assembly?

To cleave the proinsulin into insulin after it has folded into a specific shape Signup and view all the answers

What is the function of the short amyloid fibrils formed by peptide hormones of the endocrine system?

To store the hormones in an inactive form Signup and view all the answers

What is the name of the extensively studied yeast prion protein?

Sup35 Signup and view all the answers

What type of bonds are disrupted in the insulin protein that cannot spontaneously re-form efficiently?

Disulfide bonds Signup and view all the answers

What is the shape of a typical antibody molecule?

Y-shaped Signup and view all the answers

What happens when colliding molecules have poorly matching surfaces?

They form few noncovalent bonds Signup and view all the answers

What is a characteristic of enzymes within a functional class?

They are highly specific and catalyze a single type of reaction Signup and view all the answers

What happens to the rate of reaction when the enzyme molecule is saturated with substrate?

It reaches a maximum value Signup and view all the answers

What does the Km of an enzyme represent?

The concentration of substrate that allows the reaction to proceed at half its maximum rate Signup and view all the answers

How do enzymes accelerate chemical reactions?

By decreasing the activation energy Signup and view all the answers

What is the role of lysozyme in the catalysis of polysaccharide chains?

To cut the polysaccharide chain, which is its substrate Signup and view all the answers

What is the function of coenzymes in enzyme-catalyzed reactions?

To assist in enzyme-catalyzed reactions such as hydrolysis Signup and view all the answers

What is the result of the conditions created in the microenvironment of the lysozyme active site?

An impressive increase in hydrolysis rate Signup and view all the answers

What type of molecule is attached to rhodopsin in the eye?

A lightsensitive molecule called retinal Signup and view all the answers

What is the central atom of the heme ring?

Iron Signup and view all the answers

What is the purpose of a multienzyme complex in cells?

To increase the rate of cell metabolism Signup and view all the answers

What is the effect of conformational coupling between two separate binding sites?

Reciprocal effect on each other's binding Signup and view all the answers

What do GAP and GEF regulate in GTP-binding proteins?

The type of nucleotide bound Signup and view all the answers

What is the function of covalent modification patterns in cells?

To provide specific meanings to the cell Signup and view all the answers

What is a characteristic of motor proteins?

Random back-and-forth wandering Signup and view all the answers

What is a common feature of heme groups in hemoglobin?

Tightly bound to each of the four polypeptide chains Signup and view all the answers