biochemistry HIDDEN QUIZ Flashcards
maam pedroza easter egg WTF THIS IS SO MUCH
Characteristics of Proteins
> Most often, carbohydrates and lipids do not contain N.
The average nitrogen content of proteins is around 15.4% by mass. Other elements, such as phosphorous and iron, are essential constituents of certain specialized proteins.
Casein, the main protein of milk, contains phosphorous, an element that is very important in the diet of infants and children.
Hemoglobin, the oxygen-transporting protein of blood, contains iron.
Are organic compounds of high molecular weight made up ofα–amino acids joined by means of peptide linkage?
PROTEINS
They are the most important biological substances and are the fundamental constituents of cell protoplasm.
PROTEINS
Unlike carbohydrates and fats, ______ amount of protein is temporarily stored in the body
small
It has a molecular weight ranging from _______ to _________
5,000 to 8,000,000
The protein molecule is composed of ________ or even __________ of amino acids linked by peptide bonds.
hundreds or even thousands
The basic structure of an amino acid
Google it, I can’t add pictures
There are __ different groups attached to the alpha carbon atom in all of the standard amino acids
4
______, where the R group is a hydrogen atom.
glycine
With few exceptions (in some bacteria), the amino acids found in nature and proteins are __________.
L-isomers
Fischer projection formulas of amino acids:
Google it, I can’t add pictures
Classification of Amino acids:
A. According to Polarity (based on the side present)
1. Non-polar amino acids
2. Polar Neutral/Uncharged amino acids
3. Polar-acidic
4. Polar–basic
B.According to Essentiality
A complete dietary protein
An incomplete dietary protein
Complementary dietary proteins
(from the German term meaning “double ion”)
Zwitterions
It is a molecule that has a positive charge (+) charge on one atom and a negative charge (-) on another atom but has no net charge.
Zwitterions
Note that the net charge on zwitterions is ______ even though parts of the molecule carry charges.
zero
In solution and also in the solid state, ____ -______ ______ exist as zwitterions.
alpha-amino acids
It is the pH at which an amino acid exists primarily in its zwitterion form.
Isoelectric point/pH
a ) The pH is ______ (acidic)-by adding an acid such as HCl.
LOWERED
b ) The pH becomes ________ (basic) by adding a base such as NaOH.
higher
It is an amino acid that contains one amino group, one carboxyl group, and a non-polar side chain.
Non-polar amino acids
When Non-polar amino acids are incorporated into a protein, such as amino acids, they are _________
hydrophobic
They are generally found in the interior part of proteins, where there is little contact with water.
Non-polar amino acids
There are eight non-polar amino acids.
alanine, valine, leucine, proline, methionine, tryptophan, glycine, isoleucine, and phenylalanine
(GOOGLE THEIR STRUCTURES I CAN’T ADD PICTURES)
It is an amino acid that contains one amino group, one carboxyl group, and a side chain that is polar but neutral.
Polar Neutral/Uncharged amino acids
There are 7 polar neutral amino acids.
Threonine, serine, cysteine, tyrosine, glutamine, and asparagine.
(GOOGLE THEIR STRUCTURES I CAN’T ADD PICTURES)
Polar Neutral/Uncharged amino acids are ________, unlike non-polar amino acids
Hydrophilic
In solution, the Polar Neutral/Uncharged amino acids are neither ______ nor ______, and the side chain is at physiological pH.
acidic nor basic
It is an amino acid that contains one amino group and two carboxyl groups, the second of which is part of the side chain.
Polar-acidic
There are 2 polar acidic amino acids.
Glutamic acid, aspartic acid
(GOOGLE THEIR STRUCTURES I CAN’T ADD PICTURES)
In solution at physiological pH, the side chain bears a _______ charge; the side chain carboxyl group( COO—) has lost its acidic hydrogen atom.
negative charge
It is an amino acid that contains two amino groups, one carboxyl group, in which the second amino group is part of the side chain.
Polar–basic
In solution at physiological pH, the side chain bears a _________ charge;
Positive charge
There are 3 basic amino acids.
arginine (Arg), lysine (Lys), and histidine (His)
(GOOGLE THEIR STRUCTURES I CAN’T ADD PICTURES)
It is a protein that contains all of the essential amino acids in the same relative amounts in which the body needs them.
A complete dietary protein
It may or may not contain all of the non-essential amino acids
A complete dietary protein
Does not contain adequate amounts relative to the body’s needs.
An incomplete dietary protein
These are two or more incomplete dietary proteins that when combined, provide an adequate amount of all essential amino acids relative to the body’s needs.
Complementary dietary proteins
The pH at which amino acids are neutral; there will be an equal number of ________ and _________ charges.
positive (+) and negative (-)
Every amino acid has a different _________ ___.
isoelectric pH
mother of all amino acids
Alanine ( ala )
Clinical significance: it is a substrate of SGPT and SGO
SGPT- serum glutamic acid pyruvate transamylase
SGOT- serum glutamic acid oxalo transamylase
The amino acids that are associated with digestive enzymes.
Leucine ( leu ) and Isoleucine ( Ile )
The amino acid that is important to the functioning of the nervous system
Valine ( Val )
The defect on the metabolism of val, leu and ile will accumulate in the tissues, perhaps because of the absence of enzymes and that would result to a certain disease called “ ______ _______ ______ “
Maple Syrup Urine
The amino acid is known as “ helix breaker”
Proline ( pro )
Why is the amino acid is known as “ helix breaker
Because it disrupts the α – helical configuration of proteins, it inhibits the formation of α –helix
(GOOGLE IF YOU DO NOT KNOW)
Does not contain a primary amino group.
Proline ( pro )
N is bonded to 2 C-atoms ( not free )
Proline ( pro )
It is called an imino acid
Proline ( pro )
an essential amino acid in the human system
Phenylalanine ( Phe )
It will give a positive reaction with the Xanthoproteic test. ( yellow to orange. ).
Phenylalanine ( Phe )
It is important in the utilization of Vit.C and production of thyroxin
Phenylalanine ( Phe )
Some people lack the enzyme necessary to convert phe —> tyr. The phe that they obtain from their diet is instead diverted along an alternative metabolic pathway which produces phenyl pyruvic acid
-can cause mental retardation in infants-they are said to suffer phenylketonuria /pKU disease
-cannot be cured but is controlled by restricting the dietary intake of phe
-avoid foods such as meat that are rich inpheIndole Group positive with Hopkin’s Cole reaction (violet ring formation)
it is important in the utilization of B vitamins and synthesis of neurotransmitters
Tryptophan ( Trp )
Will give a positive reaction with Hopkin’s Cole reaction due to the presence of an indole group
Tryptophan ( Trp )
Needed in the formation of neurotransmitters. (chemical messenger involved in nerve cell communication
Tryptophan ( Trp )
Present in the charred portion of broiled fish and meat, which is responsible for cancer diseases.
Tryptophan ( Trp )
This amino acid initiates protein synthesis
Methionine ( Met )
It participates in transmethylation reactions as a methyl donor
Methionine ( Met )
Associated with fat metabolism
Methionine ( Met )
An important component of a phosphoprotein, the PO4-3 group, is attached to _______.
Serine ( Ser )
important in building tissues and utilization of nutrient
Threonine ( Thr )
needed in the synthesis of some thyroid hormones
Tyrosine ( Tyr )
It will give a positive reaction to Millon’s test due to the presence of the phenol ( OH ) group. ( red color )
Tyrosine ( Tyr )
Found abundant in naturally curly hair
Cysteine ( Cys )
is the simplest amino acid
Glycine ( Gly )
A major excitatory neurotransmitter
Glycine ( Gly )
It is optically inactive because of the absence of alpha asymmetric carbon.
Glycine ( Gly )
Used by the body in the detoxification of benzoic acid
Glycine ( Gly )
Benzoylation reaction
Benzoic acid + glycine becomes benzoyl glycine / hippuric acid
contains a ß - carboxyl group
Aspartic Acid ( Asp )
Its salt form is aspartate, which is a major excitatory neurotransmitter
Aspartic Acid ( Asp )
contains a gamma-carboxyl group
Glutamic Acid ( Glu )
Salt form is glutamate, a major excitatory neurotransmitter
Glutamic Acid ( Glu )
MSG (monosodium glutamate)
Glutamic Acid ( Glu )
is found in collagen
Lysine ( Lys )
Aids in the assimilation of other amino acids
Lysine ( Lys )
Contains a guanido or guanidinium group, which imparts basicity to the structure
Arginine ( Arg )
contains an imidazole or imidazolium group
Histidine ( His )
It has significant buffering capacity at physiological pH; the only acid having this property
Histidine ( His )
Will undergo decarboxylation reaction. (loss of COOH as CO2); resulting in the formation of histamine
Histidine ( His )
is responsible for any of the symptoms associated with Hay fever and other allergies
Histidine ( His )
A _________ is a chain of amino acids that is formed when the carboxyl group of the α-carbon of an amino acid reacts with the amino group of the α-carbon of the second amino acid.
peptide
The bond formed in this reaction is generally an 1_______ ______. However, for peptide proteins, the bond is called a 2________ _______.
1- amide bond, 2- peptide bond
The formation of the peptide is clearly a type of _________ ________ since water is a product after the reaction. Every peptide bond that is formed in a reaction also produces one water molecule.
dehydration reaction
2 amino acid residues
dipeptide
1__________ is the classification of peptides with three amino acid residues, 2__________ for those with four amino acids, and soon.
1- Tripeptide, 2- tetrapeptide
Normally, when a peptide has 10-20 amino acid residues, it is already referred to as an _________.
oligopeptide
When it contains more than 20 amino acid residues already, it is already referred to as _________.
polypeptide
Proteins are composed of _________
polypeptides
A peptide chain has directionality because its ends are ______
different
α-amino group is present at one end. The amino acid residue with a free α-amino group is the __-________ _______
N-terminal residue
An α-carboxyl group at the other end. The residue at the other end, which has a free α-carboxyl group, is the __-________ _______.
C-terminal residue
The sequence of amino acids in a polypeptide chain is written starting with the ___-_______ _______.
N-terminal residue
The ________ __________ of a peptide or a protein consists of the repeated sequence–N–Cα–C–, where N stands for the amino or amide nitrogen
peptide backbone
Each residue contains a ________ ______ which is a good hydrogen bond acceptor
carbonyl group (C=O)
The peptide backbone is rich in _______-________ _________
hydrogen-bonding potential
Each residue contains a carbonyl group (C=O), which is a good hydrogen bond acceptor, with the exception of ________, an NH group, which is a good hydrogen bond donor
proline
Peptides are named using the following rules:
- The C-terminal amino acid residue keeps its full name.
- All other amino acids have names that end in –yl. The –yl suffix replaces the -ine or –ic acid ending of the amino acid name, except for tryptophan (tryptophyl), cysteine (cysteinyl), glutamine (glutaminyl), and asparagine (asparaginyl).
- The amino acid naming sequence begins at the N-terminal acid residue.
Given 20 different amino acids, there are countless possible combinations of peptides.
The number of possible isomers in a peptide is given by 20n, where n is the number of amino acid residues.
Peptides that contain the same kind and number of amino acids but differ in order are called _________ _________.
Isomeric Peptides
These are peptide hormones that are both produced in the pituitary gland.
Oxytocin and Vasopressin
Each hormone is a nonapeptide, with six amino acid residues held in a loop by a disulfide bond formed from the interaction of two cysteine residues.
Oxytocin and Vasopressin
These are pentapeptide neurotransmitters produced by the brain itself. They bind to receptor sites in the brain to reduce pain.
Enkephalins
The two well–known enkephalins are____-___________ and ____-___________, whose structures differ only at the C-terminal end of the peptide; this amino acid difference is incorporated in their names.
Met-enkephalin and Leu-enkephalin
This is a tripeptide with the sequence Glu-Cys-Gly, which is present in significant concentrations in most cells and serves as an antioxidant, protecting cellular components against oxidizing agents, such as peroxides and superoxides (highly reactive species of oxygen often generated within the cell in response to bacterial invasion.
Glutathione
The structure of ____________ is a bit odd. The glutamic acid is bonded to cysteine through the side-chain carboxyl group rather than through its α-carbon carboxyl group.
Glutathione
