PROTEINS Flashcards by Ashley Quintana

A ______ is a naturally occurring, unbranched polymer in
which the monomer units are _____ _______

Proteins, amino acids

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________, the oxygen-transporting protein of blood,
contains iron.

Hemoglobin

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An amino acid is an organic compound that contains both
an amino (-NH) group and a carboxyl (-COOH) group. True or False?

FALSE, (-NH2) group and (-COOH)

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The amino acids found in proteins are always b-amino acids. True or False?

FALSE, a-amino acids

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What is α-amino acid?

an amino acid in which the amino group and the carboxyl group are attached to the α-amino.

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Amino acid that contains one amino group, one carboxyl group, and a nonpolar side chain.

Nonpolar amino acid

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There are _____ nonpolar amino acids.

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The only nonpolar amino acid that has a propyl group on its side chain which is bonded to both the α-carbon atom and the amino nitrogen atom, giving a cyclic chain.

Proline

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Some textbooks list this amino acid as a polar neutral amino acid because water can weakly interact through hydrogen bonding with the NH ring location on this side-chain ring structure, although it is non polar.

Tryptophan

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Such amino acids are hydrophilic. True or False?

FALSE, hydrophobic

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The nine nonpolar amino acids:

Glycine, Alanine, Valine, Leucine, Isoleucine, Proline, Phenylalanine, Methionine, Tryptophan

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side chain of a polar neutral amino acid is neither acidic nor basic, because the side chain is

polar but neutral

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Which of the following are not part of the group:
Serine, Arginine, Cysteine, Threonine, Asparagine, Glycine, Glutamine, Tyrosine

Arginine and Glycine

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If Arginine and Glycine are the amino acids that do not belong to the group of Polar Neutral amino acids, what group do they belong to?

Arginine = Polar Basic Amino Acids, Glycine = Non Polar Amino Acids

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An amino acid that contains one amino group, one carboxyl group, and a side chain that is polar but neutral.

Polar neutral amino acid

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The side chain of the group of this amino acid bears a negative charge

polar acidic amino acid

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polar acidic amino acid is an amino acid that contains one amino group and _____ carboxyl groups

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The second carboxyl group of a polar acidic amino acid is where to be seen?

part of the side chain.

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There are two polar acidic amino acids:

Glutamic Acid and Aspartic Acid

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polar basic amino acid is an amino acid that contains two amino groups and two carboxyl groups. True or False?

FALSE, polar basic amino acid has TWO AMINO GROUP and ONE CARBOXYL GROUP only

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the side chain of a polar basic amino acid bears a ________ charge

positive

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Draw the structure of the three polar basic amino acids and the two polar acidic amino acids.

Tignan nyo sa libro/ppt kung tama kayo

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How many essential amino acids are there? Name them all

9: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine

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Is Arginine not an essential amino acid? If so, explain your answer

It is essential, but for CHILDREN only because of the fact that it is required for their growth. It is not essential for adults,

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These amino acids which are called “essential amino acids”, must be obtained from?

DIetary proteins

What is dietary proteins?

Dietary proteins are essential nutrients that our bodies need to build and repair tissues, produce enzymes, hormones, and antibodies, and transport nutrients.

Not a question, but rather a review, click to see

Serotonin is a tryptophan derivative, while both Dopamine and Norepinephrine is a tyrosine derivative

A standard amino acid needed for protein synthesis that must be obtained from dietary sources because the human body cannot synthesize it in adequate amounts from other substances. What amino acid is being described in the sentence?

Essential Amino Acid

A __________ __________ _________ is a protein that contains all of the essential amino acids in the same relative amounts in which the body needs them

complete dietary protein

An incomplete dietary protein is a protein that does not contain adequate amounts relative to the body’s needs, of one or more of the essential amino acids. Is the statement true or false?

True

An essential amino acid that is missing, or present in inadequate amounts, in an incomplete dietary protein

Limiting amino acid

Proteins from animal sources is usually a incomplete dietary protein, while proteins from plants sources tends to be complete dietary protein. Is the statement true or false?

FALSE, they are opposite. Proteins from animals = complete dietary protein, Proteins from plants = incomplete dietary protein

_____________ _____________ _____________ are two or more incomplete dietary proteins that when combined, provide and adequate amount of all essential amino acids relative to the body’s needs

COMPLEMENTARY dietary proteins

What is the simplest standard amino acid?

Glycine

Is glycine achiral or chiral?

Glycine is achiral, all of the standard amino acids are chiral

Isoleucine and threonine possess 3 chiral centers. Is this true or false?

FALSE, it only has 2 chiral centers for both isoleucine and threonine

What are the rules for drawing Fischer Projection for amino acids?

1.) The COOH group is put at the top of the projection formula, R group at the bottom. This positions the carbon chain vertically 2.) The -NH2 group is in a horizontal position. Positioning it on the left denotes the L isomer, and positioning it on the right denotes the D isomer.

In pure form, what is the color of amino acids?

White crystalline solids

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

zwitterion

In neutral solution, carboxyl group have a tendency to lose protons (H+), producing a ________ charged species

negatively

In neutral solution, amino group have a tendency to accept protons (H+), producing a ________ charged species

positively

Is the amino group of an amino acid (H2N or NH2) structure basic or acidic?

basic

Is the carboxyl group of an amino acid (COOH) structure basic or acidic?

acidic

In solution and also in the solid state, α-amino acids exist as zwitterions. True or False?

TRUE

the net charge on a zwitterion is _____ even though parts of the molecule carry charges.

zero

The pH at which an amino acid exits primarily in its zwitterion form is called the ________ _________

isoelectric point

Cysteine is the only standard amino acid that has a side chain that contains a ______________ group.

sulfhydryl

An unbranched chain of amino acids

peptide

What is the difference between oligopeptide and polypeptide?

Oligopeptide = peptides with 10-20 amino acid Polypeptide = a long unbranched chain of amino acid

A peptide bond is a noncovalent bond between the carboxyl group of one amino acid and the amino group of another amino acid. True or False?

FALSE, covalent bond NOT NONcovalent

this refers to the backbone of the peptide

These are the repeating sequence of peptide bonds and a-carbon --CH groups in a peptide (tignan ang page 126 para mas magets)

Peptides that contain the same amino acids but in different order are different molecules (constitutional isomers) with different properties is called?

Isometric Peptides

An amino acid residue is the portion of an amino acid structure that remains, after the release of H2O. True or false?

TRUE

Give the Three Biochemically Important Peptides

Small Peptide Hormones Small Peptide Neurotransmitters Small Peptide Antioxidants

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

oxytocin and vasopressin.

Enkephaline is a type of Small Peptide Neurotransmitters. Define Enkephaline

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

________ functions as an antioxidant, protecting cellular contents from oxidizing agents such as peroxides and superoxides

glutathione

1. A simple protein is a protein in which only amino acid residues are present. 2. A conjugated protein is a protein that has one or more nonamino acid entities present in its structure in addition to one or more peptide chains. A. Both statements are true B. Both statements are false C. First statement is TRUE, Second statement is FALSE D. First statement is FALSE, Second statement is TRUE

These non-amino acid components, which may be organic or inorganic, are called prosthetic groups. True or False?

TRUE

non-amino acid group present in a conjugated protein.

prosthetic group

1. Primary protein structure is the order in which amino acids are linked together in a protein. 2. Secondary protein structure is the arrangement in space adopted by the backbone portion of a protein. A. Both statements are true B. Both statements are false C. First statement is TRUE, Second statement is FALSE D. First statement is FALSE, Second statement is TRUE

The two most common types of secondary structure of protein

alpha helix (α helix) and the beta pleated sheet (β pleated sheet)

How does the α helix and β pleated sheet differs?

▪An alpha helix 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. ▪A beta pleated sheet 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.

Identify what is being described in the sentence. the overall three-dimensional shape of a protein that results from the interactions between amino acid side chains (R groups) that are widely separated from each other within a peptide chain.

Tertiary protein structure (take note of the letter t in "three-dimensional, it refers to t of tertiary protein structure)

A protein secondary structure that is neither an a-helix nor a B-pleated sheet.

Unstructured Protein Segment

Give the classification of proteins based on shape

▪ fibrous protein ▪ globular protein ▪ membrane protein

This proteins tend to have simple, regular, linear structures.

fibrous protein

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

membrane protein

A protein whose molecules have peptide chains that are folded into spherical or globular shapes.

globular protein

globular proteins are water insoluble substances. True or False

FALSE, globular proteins are water SOLUBLE substances

How many and name the classification of proteins based on function

12: ▪ Catalytic proteins. ▪ Defense proteins. ▪ Transport proteins. ▪ Messenger proteins. ▪ Contractile proteins. ▪ Structural proteins. ▪Transmembrane proteins. ▪ Storage proteins. ▪ Regulatory proteins. ▪ Nutrient proteins. ▪ Buffer proteins. ▪ Fluid-Balance proteins.

These proteins bind (and store) small molecules for future use. An example of this protein is Myoglobin

Storage proteins. (remember that Myoglobin is an oxygen- storage protein present in muscle; the oxygen so stored is a reserve oxygen source for working muscle.)

"Many such proteins have channels through which molecules can enter and exit a cell". What type of protein base on function is being described?

Transmembrane proteins (remember membrane transport, TRANSmembrane)

"Proteins with the role of biochemical catalyst are called enzymes". What type of protein base on function is being described?

Catalytic proteins (take note of the word catalyst)

These proteins, also called immunoglobulins are central to the functioning of the body’s immune system.

Defense proteins (they are part of the immune system, 'cause it DEFENDS)

Example of this protein is Hemoglobin and Transferrin

Transport proteins (remember hemoglobin as which carries oxygen from the lungs to other organs and tissues, and transferrin which carries iron from the liver to the bone marrow)

These proteins confer stiffness and rigidity to otherwise fluid like biochemical systems. Collagen is an example of this protein

Structural proteins (they provides STRUCTURE. Remember that Collagen is a component of cartilage and a keratin gives mechanical strength as well as protective covering to hair, fingernails, feathers, hooves, and some animal shells)

These proteins transmit signals to coordinate biochemical processes between different cells, tissues, and organs.

Messenger proteins. (take note of the word "transmits")

These proteins are necessary for all forms of movement. Sperm can “swim” because of long flagella made up of _________ proteins

Contractile 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

These proteins are often found “embedded” in the exterior surface of cell membranes. These proteins are often the molecules that bind to enzymes (catalytic proteins), thereby turning them “on” and “off,” and thus controlling enzymatic action.

Regulatory proteins ('cause they regulate the channels)

__________ __________ involves the loss of the protein's three dimensional structure.

Protein Denaturation

PROTEINS Flashcards

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