BIOCHEM MIDTERM PROTEINS

Protein

It refers to a naturally-occurring, unbranched polymer in which the monomer units are amino acids.

Amino acids

These are the monomer units that make up a protein polymer.

Water

This is the most abundant molecule in cells prior to proteins.

15%

The percentage of a cell's overall mass accounted for by proteins.

15.4%

The average percentage of nitrogen content present in proteins by mass.

• Carbon (C)

• Hydrogen (H)

• Nitrogen (N)

• Oxygen (O)

• Sulfur (S)

Enumerate the 5 main elements that make up the elemental composition of proteins.

• Iron (Fe)

• Phosphorus (P)

Enumerate 2 specific additional elements present in some specialized proteins (aside from C, H, N, O, S).

Water, Proteins

List TWO molecules/substances that make up the highest mass percentages in a cell.

Unbranched

The structural shape description of a protein polymer in which the monomer units are amino acids.

Peptide

The term used for a protein's specific definition, characterized as having at least 40 amino acid residues present.

40

The minimum number of amino acid residues required for a peptide to be specifically defined as a protein.

Polypeptide

The term often used interchangeably with "protein".

Several proteins

The protein category that contains >10,000 amino acid residues.

Common proteins

The protein category that contains 400–500 amino acid residues.

Small proteins

The protein category that contains 40–100 amino acid residues.

Monomeric

The type of protein that contains only one polypeptide chain.

Multimeric

The type of protein that contains two or more polypeptide chains.

Monomeric, Multimeric

Enumerate the TWO classifications of proteins based on the number of polypeptide chains present

• Several proteins (contains >10,000 amino acid residues)

• Common proteins (contains 400–500 amino acid residues)

• Small proteins (contains 40–100 amino acid residues)

Enumerate the THREE categories/types of proteins based on the number of amino acid residues they contain.

Simple protein

A protein in which only amino acid residues are present.

Conjugated (complex) protein

A protein that has one or more non-amino acid entities present in its structure.

Prosthetic group

The term for the non-amino acid entity present in a conjugated protein.

Organic or inorganic

The type of prosthetic group that can be attached to a conjugated protein.

Albuminoids

The class of simple proteins that includes keratin in skin, hair, and nails, as well as collagen in cartilage.

Collagen

Simple protein found in cartilage.

Albumins

The class of simple proteins that includes egg albumin and serum albumin.

Keratin

A simple protein present in skin, hair, and nails (and categorized under albuminoids or listed as a simple protein)

Histones

Simple proteins found in chromatin within chromosomes.

Actin & Myosin

Simple proteins that are primary muscle proteins involved in contraction.

Hemoproteins

The class of conjugated proteins with a heme unit as its prosthetic group

Lipoproteins

The class of conjugated proteins with a lipid as its prosthetic group.

Glycoproteins

The class of conjugated proteins with a carbohydrate as its prosthetic group.

Phosphoproteins

The class of conjugated proteins with a phosphate group as its prosthetic group.

Nucleoproteins

The class of conjugated proteins with a nucleic acid as its prosthetic group.

Metalloproteins

The class of conjugated proteins with a metal ion as its prosthetic group.

Heme unit

The prosthetic group present in hemoproteins.

Lipid

The prosthetic group present in lipoproteins.

Carbohydrate

The prosthetic group present in glycoproteins.

Phosphate group

The prosthetic group present in phosphoproteins.

Nucleic acid

The prosthetic group present in nucleoproteins.

Metal ion

The prosthetic group present in metalloproteins.

Hemoglobin

The specific hemoprotein that acts as a carrier of O2 in blood.

Myoglobin

The specific hemoprotein that acts as an oxygen binder in muscles.

Low-density lipoprotein (LDL) / High-density lipoprotein (HDL)

The specific lipoproteins that serve as lipid carriers.

Gamma globulin

The specific glycoprotein that functions as an antibody.

Mucin

The specific glycoprotein that acts as a lubricant in mucous secretions.

Interferon

The specific glycoprotein that provides antiviral protection.

Glycogen phosphorylase

The specific phosphoprotein that serves as an enzyme in glycogen phosphorylation.

Ribosomes

The specific nucleoprotein that serves as the site for protein synthesis in cells.

Viruses

The specific nucleoprotein defined as a self-replicating, infectious complex.

Iron-ferritin

The specific metalloprotein that acts as a storage complex for iron.

Zinc-alcohol dehydrogenase

The specific metalloprotein that acts as an enzyme in alcohol oxidation.

• Simple proteins

• Conjugated (complex) proteins

Enumerate the TWO classifications of proteins based on chemical composition.

• Albuminoids

• Albumins

• Keratin

• Histones

• Actin & Myosin

Enumerate the FIVE examples of simple proteins.

• Hemoproteins

• Lipoproteins

• Glycoproteins

• Phosphoproteins

• Nucleoproteins

• Metalloproteins

Enumerate the SIX classes of conjugated proteins.

• Hemoglobin

• Myoglobin

Enumerate the TWO specific examples of hemoproteins.

• Low-density lipoprotein (LDL)

• High-density lipoprotein (HDL)

Enumerate the TWO specific examples of lipoproteins.

• Gamma globulin

• Mucin

• Interferon

Enumerate the THREE specific examples of glycoproteins.

Glycogen phosphorylase

Enumerate the ONE specific example of phosphoproteins.

• Ribosomes

• Viruses

Enumerate the TWO specific examples of nucleoproteins.

• Iron–ferritin

• Zinc–alcohol dehydrogenase

Enumerate the TWO specific examples of metalloproteins.

Fibrous Proteins

The classification of proteins based on shape whose polypeptide chains are arranged in long strands or sheets.

Globular Proteins

The classification of proteins based on shape whose polypeptide chains are folded into spherical or globular shapes.

Water-insoluble

The solubility characteristic of fibrous proteins in water.

Water-soluble

The solubility characteristic of globular proteins in water.

Structural functions

The general functional type associated with fibrous proteins.

Dynamic functions

The general functional type associated with globular proteins.

Interior

The location of nonpolar amino acids within the structure of a globular protein.

Surface

The location of polar amino acids within the structure of a globular protein.

Long, rod-shaped or string-like

The physical shape description of fibrous protein molecules that allows them to intertwine and form strong fibers.

• Fibrous proteins

• Globular proteins

Enumerate the TWO classifications of proteins based on shape.

• Alpha-Keratin

• Collagen

Enumerate the TWO specific examples of fibrous proteins.

• Myoglobin

• Hemoglobin

Enumerate the TWO specific examples of globular proteins.

Keratin

Fibrous protein found in wool, feathers, hooves, silk, and fingernails.

Collagen

Fibrous protein found in tendons, bone, and other connective tissue.

Elastin

Fibrous protein found in blood vessels and ligaments.

Myosin

Fibrous protein found in muscle tissue.

Fibrin

Fibrous protein found in blood clots.

Insulin

Globular protein that serves as a regulatory hormone for controlling glucose metabolism.

Myoglobin

Globular protein involved in oxygen storage in muscles.

Hemoglobin

Globular protein involved in oxygen transport in blood.

Transferrin

Globular protein involved in iron transport in blood.

Immunoglobulin

Globular protein involved in immune system responses.

• Keratin

• Collagen

• Elastin

• Myosin

• Fibrin

Enumerate the FIVE common fibrous proteins.

• Insulin

• Myoglobin

• Hemoglobin

• Transferrin

• Immunoglobulin

Enumerate the FIVE common globular proteins.

Proteins

These biomolecules play crucial roles in most biochemical processes.

Diversity of functions

The molecular attribute of proteins whose diversity far exceeds the role of other biochemical molecules.

Specifically and strongly

The manner in which proteins bind small molecules, which contributes to their functional versatility.

Fiber-like structures

The type of structures proteins can form when binding to other proteins.

Cell membranes

The structural location where proteins can be integrated, contributing to their functional versatility.

• Ability to bind small molecules specifically and strongly

• Ability to bind other proteins and form fiber-like structures

• Ability integrated into cell membranes

Enumerate the THREE factors/abilities from which the functional versatility of proteins stems.

Catalytic proteins

The major functional category of proteins where enzymes are best known for their role.

Enzymes

The specific type of catalytic proteins that drive almost every chemical reaction in the body.

Defense proteins

The functional category of proteins to which immunoglobulins or antibodies belong.

Immunoglobulins or antibodies

Proteins central to the functioning of the body's immune system.

Transport proteins

The category of proteins that bind small biomolecules and transport them to other locations in the body to be released on demand.

Messenger proteins

The category of proteins that transmit signals to coordinate biochemical processes between different cells, tissues, and organs.

Insulin and glucagon

Two messenger proteins that regulate carbohydrate metabolism.

Human growth hormone

A messenger protein that regulates body growth.

Contractile proteins

The category of proteins necessary for all forms of movement.