biochemistry HIDDEN QUIZ

Question 1

Characteristics of Proteins

Answer 1

> 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.

Question 2

Are organic compounds of high molecular weight made up ofα–amino acids joined by means of peptide linkage?

Answer 2

PROTEINS

Question 3

They are the most important biological substances and are the fundamental constituents of cell protoplasm.

Answer 3

PROTEINS

Question 4

Unlike carbohydrates and fats, ______ amount of protein is temporarily stored in the body

Answer 4

small

Question 5

It has a molecular weight ranging from _______ to _________

Answer 5

5,000 to 8,000,000

Question 6

The protein molecule is composed of ________ or even __________ of amino acids linked by peptide bonds.

Answer 6

hundreds or even thousands

Question 7

The basic structure of an amino acid

Answer 7

Google it, I can’t add pictures

Question 8

There are __ different groups attached to the alpha carbon atom in all of the standard amino acids

Answer 8

4

Question 9

______, where the R group is a hydrogen atom.

Answer 9

glycine

Question 10

With few exceptions (in some bacteria), the amino acids found in nature and proteins are __________.

Answer 10

L-isomers

Question 11

Fischer projection formulas of amino acids:

Answer 11

Google it, I can’t add pictures

Question 12

Classification of Amino acids:

Answer 12

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

Question 13

(from the German term meaning “double ion”)

Answer 13

Zwitterions

Question 14

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.

Answer 14

Zwitterions

Question 15

Note that the net charge on zwitterions is ______ even though parts of the molecule carry charges.

Answer 15

zero

Question 16

In solution and also in the solid state, ____ -______ ______ exist as zwitterions.

Answer 16

alpha-amino acids

Question 17

It is the pH at which an amino acid exists primarily in its zwitterion form.

Answer 17

Isoelectric point/pH

Question 18

a ) The pH is ______ (acidic)-by adding an acid such as HCl.

Answer 18

LOWERED

Question 19

b ) The pH becomes ________ (basic) by adding a base such as NaOH.

Answer 19

higher

Question 20

It is an amino acid that contains one amino group, one carboxyl group, and a non-polar side chain.

Answer 20

Non-polar amino acids

Question 21

When Non-polar amino acids are incorporated into a protein, such as amino acids, they are _________

Answer 21

hydrophobic

Question 22

They are generally found in the interior part of proteins, where there is little contact with water.

Answer 22

Non-polar amino acids

Question 23

There are eight non-polar amino acids.

Answer 23

alanine, valine, leucine, proline, methionine, tryptophan, glycine, isoleucine, and phenylalanine

(GOOGLE THEIR STRUCTURES I CAN’T ADD PICTURES)

Question 24

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

Answer 24

Polar Neutral/Uncharged amino acids

Question 25

There are 7 polar neutral amino acids.

Answer 25

Threonine, serine, cysteine, tyrosine, glutamine, and asparagine. (GOOGLE THEIR STRUCTURES I CAN'T ADD PICTURES)

Question 26

Polar Neutral/Uncharged amino acids are ________, unlike non-polar amino acids

Answer 26

Hydrophilic

Question 27

In solution, the Polar Neutral/Uncharged amino acids are neither ______ nor ______, and the side chain is at physiological pH.

Answer 27

acidic nor basic

Question 28

It is an amino acid that contains one amino group and two carboxyl groups, the second of which is part of the side chain.

Answer 28

Polar-acidic

Question 29

There are 2 polar acidic amino acids.

Answer 29

Glutamic acid, aspartic acid (GOOGLE THEIR STRUCTURES I CAN'T ADD PICTURES)

Question 30

In solution at physiological pH, the side chain bears a _______ charge; the side chain carboxyl group( COO—) has lost its acidic hydrogen atom.

Answer 30

negative charge

Question 31

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.

Answer 31

Polar–basic

Question 32

In solution at physiological pH, the side chain bears a _________ charge;

Answer 32

Positive charge

Question 33

There are 3 basic amino acids.

Answer 33

arginine (Arg), lysine (Lys), and histidine (His) (GOOGLE THEIR STRUCTURES I CAN'T ADD PICTURES)

Question 34

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

Answer 34

A complete dietary protein

Question 35

It may or may not contain all of the non-essential amino acids

Answer 35

A complete dietary protein

Question 36

Does not contain adequate amounts relative to the body’s needs.

Answer 36

An incomplete dietary protein

Question 37

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.

Answer 37

Complementary dietary proteins

Question 38

The pH at which amino acids are neutral; there will be an equal number of ________ and _________ charges.

Answer 38

positive (+) and negative (-)

Question 39

Every amino acid has a different _________ ___.

Answer 39

isoelectric pH

Question 40

mother of all amino acids

Answer 40

Alanine ( ala )

Question 41

Clinical significance: it is a substrate of SGPT and SGO

Answer 41

SGPT- serum glutamic acid pyruvate transamylase SGOT- serum glutamic acid oxalo transamylase

Question 42

The amino acids that are associated with digestive enzymes.

Answer 42

Leucine ( leu ) and Isoleucine ( Ile )

Question 43

The amino acid that is important to the functioning of the nervous system

Answer 43

Valine ( Val )

Question 44

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 “ ______ _______ ______ “

Answer 44

Maple Syrup Urine

Question 45

The amino acid is known as “ helix breaker"

Answer 45

Proline ( pro )

Question 46

Why is the amino acid is known as “ helix breaker

Answer 46

Because it disrupts the α – helical configuration of proteins, it inhibits the formation of α –helix (GOOGLE IF YOU DO NOT KNOW)

Question 47

Does not contain a primary amino group.

Answer 47

Proline ( pro )

Question 48

N is bonded to 2 C-atoms ( not free )

Answer 48

Proline ( pro )

Question 49

It is called an imino acid

Answer 49

Proline ( pro )

Question 50

an essential amino acid in the human system

Answer 50

Phenylalanine ( Phe )

Question 51

It will give a positive reaction with the Xanthoproteic test. ( yellow to orange. ).

Answer 51

Phenylalanine ( Phe )

Question 52

It is important in the utilization of Vit.C and production of thyroxin

Answer 52

Phenylalanine ( Phe )

Question 53

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

Answer 53

-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)

Question 54

it is important in the utilization of B vitamins and synthesis of neurotransmitters

Answer 54

Tryptophan ( Trp )

Question 55

Will give a positive reaction with Hopkin’s Cole reaction due to the presence of an indole group

Answer 55

Tryptophan ( Trp )

Question 56

Needed in the formation of neurotransmitters. (chemical messenger involved in nerve cell communication

Answer 56

Tryptophan ( Trp )

Question 57

Present in the charred portion of broiled fish and meat, which is responsible for cancer diseases.

Answer 57

Tryptophan ( Trp )

Question 58

This amino acid initiates protein synthesis

Answer 58

Methionine ( Met )

Question 59

It participates in transmethylation reactions as a methyl donor

Answer 59

Methionine ( Met )

Question 60

Associated with fat metabolism

Answer 60

Methionine ( Met )

Question 61

An important component of a phosphoprotein, the PO4-3 group, is attached to _______.

Answer 61

Serine ( Ser )

Question 62

important in building tissues and utilization of nutrient

Answer 62

Threonine ( Thr )

Question 63

needed in the synthesis of some thyroid hormones

Answer 63

Tyrosine ( Tyr )

Question 64

It will give a positive reaction to Millon’s test due to the presence of the phenol ( OH ) group. ( red color )

Answer 64

Tyrosine ( Tyr )

Question 65

Found abundant in naturally curly hair

Answer 65

Cysteine ( Cys )

Question 66

is the simplest amino acid

Answer 66

Glycine ( Gly )

Question 67

A major excitatory neurotransmitter

Answer 67

Glycine ( Gly )

Question 68

It is optically inactive because of the absence of alpha asymmetric carbon.

Answer 68

Glycine ( Gly )

Question 69

Used by the body in the detoxification of benzoic acid

Answer 69

Glycine ( Gly )

Question 70

Benzoylation reaction

Answer 70

Benzoic acid + glycine becomes benzoyl glycine / hippuric acid

Question 71

contains a ß - carboxyl group

Answer 71

Aspartic Acid ( Asp )

Question 72

Its salt form is aspartate, which is a major excitatory neurotransmitter

Answer 72

Aspartic Acid ( Asp )

Question 73

contains a gamma-carboxyl group

Answer 73

Glutamic Acid ( Glu )

Question 74

Salt form is glutamate, a major excitatory neurotransmitter

Answer 74

Glutamic Acid ( Glu )

Question 75

MSG (monosodium glutamate)

Answer 75

Glutamic Acid ( Glu )

Question 76

is found in collagen

Answer 76

Lysine ( Lys )

Question 77

Aids in the assimilation of other amino acids

Answer 77

Lysine ( Lys )

Question 78

Contains a guanido or guanidinium group, which imparts basicity to the structure

Answer 78

Arginine ( Arg )

Question 79

contains an imidazole or imidazolium group

Answer 79

Histidine ( His )

Question 80

It has significant buffering capacity at physiological pH; the only acid having this property

Answer 80

Histidine ( His )

Question 81

Will undergo decarboxylation reaction. (loss of COOH as CO2); resulting in the formation of histamine

Answer 81

Histidine ( His )

Question 82

is responsible for any of the symptoms associated with Hay fever and other allergies

Answer 82

Histidine ( His )

Question 83

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.

Answer 83

peptide

Question 84

The bond formed in this reaction is generally an 1_______ ______. However, for peptide proteins, the bond is called a 2________ _______.

Answer 84

1- amide bond, 2- peptide bond

Question 85

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.

Answer 85

dehydration reaction

Question 86

2 amino acid residues

Answer 86

dipeptide

Question 87

1__________ is the classification of peptides with three amino acid residues, 2__________ for those with four amino acids, and soon.

Answer 87

1- Tripeptide, 2- tetrapeptide

Question 88

Normally, when a peptide has 10-20 amino acid residues, it is already referred to as an _________.

Answer 88

oligopeptide

Question 89

When it contains more than 20 amino acid residues already, it is already referred to as _________.

Answer 89

polypeptide

Question 90

Proteins are composed of _________

Answer 90

polypeptides

Question 91

A peptide chain has directionality because its ends are ______

Answer 91

different

Question 92

α-amino group is present at one end. The amino acid residue with a free α-amino group is the __-________ _______

Answer 92

N-terminal residue

Question 93

An α-carboxyl group at the other end. The residue at the other end, which has a free α-carboxyl group, is the __-________ _______.

Answer 93

C-terminal residue

Question 94

The sequence of amino acids in a polypeptide chain is written starting with the ___-_______ _______.

Answer 94

N-terminal residue

Question 95

The ________ __________ of a peptide or a protein consists of the repeated sequence–N–Cα–C–, where N stands for the amino or amide nitrogen

Answer 95

peptide backbone

Question 96

Each residue contains a ________ ______ which is a good hydrogen bond acceptor

Answer 96

carbonyl group (C=O)

Question 97

The peptide backbone is rich in _______-________ _________

Answer 97

hydrogen-bonding potential

Question 98

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

Answer 98

proline

Question 99

Peptides are named using the following rules:

Answer 99

1. The C-terminal amino acid residue keeps its full name. 2. 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). 3. The amino acid naming sequence begins at the N-terminal acid residue.

Question 100

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 _________ _________.

Answer 100

Isomeric Peptides

Question 101

These are peptide hormones that are both produced in the pituitary gland.

Answer 101

Oxytocin and Vasopressin

Question 102

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.

Answer 102

Oxytocin and Vasopressin

Question 103

These are pentapeptide neurotransmitters produced by the brain itself. They bind to receptor sites in the brain to reduce pain.

Answer 103

Enkephalins

Question 104

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.

Answer 104

Met-enkephalin and Leu-enkephalin

Question 105

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.

Answer 105

Glutathione

Question 106

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.

Answer 106

Glutathione