PROTEINS Flashcards by DEL ROSARIO PHOEBE

is a naturally occurring, unbranched polymer in which the monomer
units are amino acids

Protein

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is an amino acid in which the amino group and the carboxyl group are
attached to the a-carbon atom. The general structural formula for a amino acid is

a Amino acid

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is one of the 20 a-amino acids normally found in proteins

standard amino acid

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is an amino acid that contains one amino group, one
carboxyl group, and a nonpolar side chain. When incorporated into a protein, such amino
acids are hydrophobic (“water-fearing”)

Nonpolar amino acids

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is an amino acid that contains one amino group, one
carboxyl group, and a side chain that is polar but neutral. polar neutral amino acid is neither acidic nor basic

polar neutral amino acid

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is an amino acid that contains one amino group and
two carboxyl groups, the second being part of the side chain. side chain of a polar acidic amino acid bears a negative charge

Polar Acidic amino acids

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is an amino acid that contains two amino groups and
one carboxyl group, the second amino group being part of the side chain. , the side chain of a polar basic amino acid bears a positive charge.

Polar basic amino acid.

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List all the amino acids of Nonpolar

Glycine, alanine, valine, leucine, Isoleucine, proline, Phenylalanine, methionine, tryptophan.

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lists all the amino acids of the polar acidic amino acid

Aspartic acid and Glutamic Acid

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list all the amino acids in polar neutral amino acids

threonine, tyrosine, cysteine, asparagine, glutamine.

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List all the amino acids of the polar basic amino acids

Histidine, lysine, Arginine.

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List all down the 11 essential amino acid

Arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, valine, threonine, tryptophan, valine.

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is a protein that contains all
the essential amino acids in approximately the same relative
amounts in which the human body needs them.

Complete dietary Protein

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is an amino acid needed in the human
body that must be obtained from dietary sources because it cannot
be synthesized within the body from other substances in adequate
amounts

essential amino acid

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the simplest of the standard
amino acids, is achiral. All of the
other standard amino acids are chiral.

Glycine

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carboxyl groups tend to lose
protons (H+) they will have?

producing a negatively charged species

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, amino groups have a tendency to accept protons (H+) they will have

producing a positively charged species

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is a molecule that has a positive charge on one atom and a negative charge
on another atom, but which has no net charge.

zwitterion

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Strong intermolecular forces between
the positive and negative centers of
zwitterions are the cause of the high?

Melting points of amino acids

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is the pH at which an amino acid solution has no net charge because an
equal number of positive and negative charges are present

Isoelectric Point

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Isoelectric point from what range?

4.8 to 6.3

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is the process of separating charged molecules on the basis of their migration toward charged electrodes associated with an electric field.

Electrophoresis

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that has a side chain that contains a sulfhydryl group

Cysteine.

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is an unbranched chain of amino acids, each joined to the next by a peptide bond.

peptide

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is a long unbranched chain of amino acids, each joined to the next by a peptide bond

polypeptide

is a covalent bond between the carboxyl group of one amino acid and the amino group of another amino acid

Peptide bond

is the portion of an amino acid structure that remains, after the release of H2O, when an amino acid participates in peptide bond formation as it becomes part of a peptide chain.

Amino acid residues.

the same amino acids but in different order are different molecules (constitutional isomers) with different properties

Isomeric Peptides

The two best-known peptide hormones, both produced by the pituitary gland.

oxytocin and vasopressin

plays a role in stimulating the flow of milk in a nursing mother

Oxytocin

are pentapeptide neurotransmitters produced by the brain itself that bind at receptor sites in the brain to reduce pain

Enkephalins

is a protein in which only one peptide chain is present

monomeric protein

is a protein in which more than one peptide chain is present

multimeric protein

The peptide chains present in multimeric proteins are called

Protein subunits

is a protein in which only amino acid residues are present

simple protein

is a protein that has one or more nonomino acid entities present in its structure in addition to one or more peptide chains

conjugated protein

non-amino acid group present in a conjugated protein.

prosthetic group

is the order in which amino acids are linked together in a protein

Primary protein structure

is the arrangement in space adopted by the backbone portion of a protein

Secondary protein structure

is a protein secondary structure in which a single protein chain adopts a shape that resembles a coiled spring (helix), with the coil configuration maintained by hydrogen bonds

alpha helix structure

is a protein secondary structure in which two fully extended protein chain segments in the same or different molecules are held together by hydrogen bonds

beta-pleated sheet structure

used in describing portions of a protein structure is somewhat of a misnomer because all molecules of a given protein exhibit identical unstructured segment

Unstructured

is the overall three-dimensional shape of a protein that results from the interactions between amino acid side chains

Tertiary protein structure

is the organization among the various peptide chains in a multimeric protein

Quaternary protein structure

The regularly repeating ordered spatial arrangements of amino acids near each other in the protein chain, which result from hydrogen bonds between carbonyl oxygen atoms and amino hydrogen atoms

SECONDARY STRUCTURE

The sequence of amino acids present in a protein’s peptide chain or chains

PRIMARY STRUCTURE

Hydrogen bonds between two side-by-side chains, or a single chain that is folded back on itself

Beta Pleated Sheet

Hydrogen bonds between every fourth amino acid

ALPHA HELIX

The overall three-dimensional shape that results from the attractive forces between amino acid side chains (R groups) that are not near each other in the protein chain

TERTIARY STRUCTURE

The three-dimensional shape of a protein consisting of two or more independent peptide chains, which results from noncovalent interactions between R group

QUATERNARY STRUCTURE

is a protein whose molecules have an elongated shape with one dimension much longer than the others

fibrous protein

is a protein whose molecules have peptide chains that are folded into spherical or globular shapes

globular protein

is a protein that is found associated with a membrane system of a cell

Membrane Protein

is particularly abundant in nature, where it is found in protective coatings for organisms

Keratin

the most abundant of all proteins in humans (30% of total body protein), is a major structural material in tendons, ligaments, blood vessels, and skin

Collagen

transports oxygen from the lungs to tissue

Hemoglobin

Proteins are probably best known for their role as catalysts

Catalytic proteins

functions as an oxygen storage molecule in muscles

Myoglobin

These proteins, also called immunoglobulins or antibodies are central to the functioning of the body’s immune system. They bind to foreign substances, such as bacteria and viruses, to help combat invasion of the body by foreign particles.

Defense Proteins

These proteins bind to particular small biomolecules and transport them to other locations in the body and then release the small molecules as needed at the destination location

Transport proteins

These proteins transmit signals to coordinate biochemical processes between different cells, tissues, and organs that regulate body processes are messenger proteins, including insulin and glucagon

Messenger proteins.

These proteins confer stiffness and rigidity to otherwise fluidlike biochemical systems. Collagen is a component of cartilage, and a keratin gives mechanical strength as well as a protective covering to hair, fingernails, feathers, hooves, and some animal shells.

Structural proteins

These proteins are necessary for all forms of movement. Muscles are composed of filament-like contractile proteins that, in response to nerve stimuli, undergo conformation changes that involve contraction and extension. Sperm can “swim” because of long flagella made up of contractile proteins.

Contractile proteins.

help control the movement of small molecules and ions through the cell membrane

Transmembrane proteins

These proteins are often found “embedded” in the exterior surface of cell membranes. They act as sites at which messenger molecules, including messenger proteins such as insulin, can bind and thereby initiate the effect that the messenger “carries.”

Regulatory proteins.

These proteins bind (and store) small molecules for future use. During the degradation of hemoglobin, the iron atoms present are released and become part of ferritin, an iron-storage protein, which saves the iron for use in the biosynthesis of new hemoglobin molecules.

Storage proteins

These proteins are particularly important in the early stages of life, from embryo to infant. Casein, found in milk, and ovalbumin, found in egg white, are two examples of such proteins

Nutrient proteins.

is the partial or complete disorganization of a protein’s characteristic three-dimensional shape as a result of disruption of its secondary, tertiary, and quaternary structural interactions

Protein denaturation

is a protein that contains carbohydrates or carbohydrate derivatives in addition to amino acids

Glycoproteins

is a glycoprotein produced by an organism as a protective response to the invasion of microorganisms or foreign molecules

Immunoglobulins

is a foreign substance, such as a bacterium or virus, that invades the human body

Antigens

is a conjugated protein that contains lipids in addition to amino acids

lipoprotein

is a biochemical molecule that counteracts a specific antigen.

Antibody

is a lipoprotein that is involved in the transport system for lipids in the bloodstream.

plasma lipoprotein

Their function is to transport dietary triacylglycerols from the intestine to the liver and to adipose tissue

Chylomicrons.

Their function is to transport cholesterol synthesized in the liver to cells throughout the body.

Low-density lipoproteins (LDL)

Their function is to transport triacylglycerols synthesized in the liver to adipose tissue.

Very-low-density lipoproteins (VLDL)

Their function is to collect excess cholesterol from body tissues and transport it back to the liver for degradation to bile acids

High-density lipoproteins (HDL)