Nbde Biochemistry/physiology Pro/aa

Front 1

Of the 20 AA commonly found in proteins, how many are not essential in the adult diet because they can be synthesized in the body?

Back 1

11

Front 2

What are the essential AA's?

Back 2

Histidine
Leucine
Isoleucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Front 3

What are the nonessential AA's?

Back 3

Alanine
Arginine
Asparginine
Aspartic acid
Cysteine
Glutamic acid
Glutamine
Glycine
Proline
Serine
Tyrosine

Front 4

AA's can also be classified as _____, _____, or both depending on the nature of their metabolic pathway.

Back 4

Ketogenic
Glucogenic

Front 5

Amino acids whose catabolism yields either acetoacetate or one of its precursors, acetyl-CoA or acetoacetyl-CoA.
What are some examples?

Back 5

Ketogenic
Leucine and Lysine

Front 6

Amino acids whose catabolism yields pyruvate or one of the intermediates of the citric acid cycle.
What are some examples?

Back 6

Glucogenic
Remaining AA's

Front 7

Amino acids whose catabolism yields both types of end products.
What are some examples?

Back 7

Glucogenic and ketogenic
Tyrosine
Isoleucine
Phenylalanine
Tryptophan

Front 8

What does a chromosome consist of?
What is this called?

Back 8

DNA complexed with equal mass of proteins
Chromatin

Front 9

What are the standard proteins found in chromatin?
What are these proteins rich in (AA)?

Back 9

Histones (H1, H2A, H2B, H3, H4)
Arginine, Lysine (Pos. charge)

Front 10

What part of the Arginine and Lysine AA's makes them ideal for binding to the DNA in chromatin?

Back 10

Free amino group on their R group attracts (H+) which comes from negatively charged DNA

Front 11

Histones package and order the DNA into structural units called _____

Back 11

Nucleosomes

Front 12

What must be done to nucleosome structure to allow for DNA replication and transcription to begin?

Back 12

Phosphorylation of Serine and threonine - Replication
Acetylation of Lysine - transcription

Front 13

Generally Amino acids have a central or _____ _____ to which is attached a _____ _____, a _____ _____, an _____ _____ and a fourth group that differs from one amino acid to another and is often indicated by the letter _____.

Back 13

Alpha carbon
hydrogen atom
carboxyl group
amino group
R

Front 14

Bond formed from alpha amino acid group of one amino acid to the alpha carboxyl group of another.
What is two of these bonds?

Back 14

Peptide bond
Dipeptide

Front 15

How many AA's are required to constitute a polypeptide?

Back 15

10 or more

Front 16

A protein is a polypeptide chain of approx. _____ or more AA's linked by polypeptide bonds.

Back 16

100

Front 17

The order of AA's in a protein from the amino terminal to the carboxy terminal of the protein chain is referred to as the _____ _____.

Back 17

Primary structure

Front 18

What are globulins that are made by immune cells, specifically B-lymphocytes and their derivative plasma cells in the lymphoid system?

Back 18

Gamma globulins

Front 19

All plasma proteins are synthesized in _____ except gamma globulins.

Back 19

Liver

Front 20

60% of plasma proteins are made up of _____.

Back 20

Albumin

Front 21

_____ make up 35% of plasma proteins and are used in the transport of ions, hormones, and lipids assisting in immune function.

Back 21

Globulins

Front 22

4% of plasma proteins is _____, and this is essential in the clotting of blood and can be converted into the insoluble form _____.

Back 22

Fibrinogen
Fibrin

Front 23

_____ proteins make up less than 1% of plasma proteins, are proteins such as enzymes, proenzymes, and hormones.

Back 23

Regulatory

Front 24

_____ proteins act as buffers that help stabilize the pH of the internal environment

Back 24

Plasma

Front 25

_____ proteins absorb hydrogen ions generated by the body's metabolic processes.

Back 25

Intracellular

Front 26

What proteins are responsible for the transport in the blood of triglycerides, phospholipids, cholesterol, and cholesterol esters from the liver to tissues or organs?

Back 26

Lipoprotein (chylomicrons, VLDL, LDL, HDL)

Front 27

What protein is used for iron transport?

Back 27

Transferrin

Front 28

What is a blood clotting protein?

Back 28

Prothrombin

Front 29

Peptide bonds are generally not cleaved by organic solvents or _____, but it is susceptible to _____ _____.

Back 29

Urea
Strong Acids

Front 30

What is the general configuration of peptide bonds?
What is its charge?

Back 30

Trans Bond
Uncharged but polar

Front 31

_____ due to formation of a tertiary amine restricts the range of rotation of the alpha-carbon in the peptide bond.

Back 31

Proline

Front 32

What is the general thought that is the function of the Cysteine bond in proteins?
What are some examples of this type of protein?

Back 32

Stabilize protein structure
Insulin and Immunoglobulins

Front 33

A _____ is a single AA unit within a polypeptide chain.
_____ is an AA that is found in many proteins.
_____ is the only non-chiral AA.

Back 33

Residue
Cystine
Glycine

Front 34

_____ is a constituent of collagen, and is rarely found in any other protein. It provides stability to the triple helical structure of collagen via _____ bonding.

Back 34

Hydroxyproline
Hydrogen

Front 35

What is a monomeric heme protein that is found mainly in muscle tissues and serves as an intracellular storage site for oxygen to be released in times of oxygen deprivation?

Back 35

Myoglobin

Front 36

What has a much greater affinity for oxygen?
Myoglobin/Hemoglobin

Back 36

Myoglobin

Front 37

What binds more strongly to a Heme atom?
Carbon monoxide/ Oxygen

Back 37

Carbon Monoxide

Front 38

What configuration are all amino acids found in proteins?

Back 38

L-configuration

Front 39

Compounds that have the same composition and the same order of atomic connections, but different molecular arrangements.

Back 39

Stereoisomers

Front 40

In all standard amino acids, the _____ is asymmetric, bonded to four different substituent groups. This is known as a _____ _____.

Back 40

Alpha carbon
Chiral center

Front 41

All molecules with a chiral center are also _____ active.

Back 41

Optically active

Front 42

The classification and naming of stereoisomers are based on the ______ _____ of the four substituents. The basic sugar to which this is referenced is what?

Back 42

Absolute configuration
Glyceraldehyde

Front 43

What does the L designation stand for?
What does the D desiglation stand for?

Back 43

Levorotatory
Dextrorotatory

Front 44

Where are D-amino acids found?

Back 44

Some antibiotics and bacterial cell walls

Front 45

Where are cytochromes found?

Back 45

mitochondria and chloroplasts

Front 46

What are membrane bound hemoproteins that contain heme groups and carry out electron transport?

Back 46

Cytochromes

Front 47

Cytochromes are found either as _____ proteins or as subunits of bigger enzymatic complexes that catalyze _____ reactions.

Back 47

Monomeric
Redox

Front 48

Cytochrome receives electrons from the reduced from of _____. Each contains a heme group made of a _____ ring containing an atom of iron.
What is the iron reduced to as the electron carrier atom?

Back 48

Coenzyme Q (ubiquinone)
Porphyrin ring
From Fe3+ - Fe2+

Front 49

How are cytochromes distinguished?
What are their classifications?

Back 49

Differences in light absorption spectra.
b,c1,c,a3,a

Front 50

Cytochromes _____ are terminal members of the electron transport chain. They exist as a complex, which is called _____ or _____ _____ complex.

Back 50

a3 and a
Complex IV
Cytochrome Oxidase

Front 51

What are a five membered, nitrogen-containing rings in a cyclic structure called?
Besides cytochromes where are these rings found?

Back 51

Porphyrin
Hemoglobin / Cytochrome P450

Front 52

What are the precursors to the biosynthesis of porphyrin rings?

Back 52

Glycine and Succinyl-CoA

Front 53

What can amino acids lose which will turn them into alpha-keto acids?
What cycle will this allow the amino acid to enter?

Back 53

Amino group
Krebs cycle

Front 54

What is an alpha-keto acid?

Back 54

An amino acid that has an oxygen attached in place of the amino group

Front 55

What does alpha-ketoglutarate give rise to?
What is this a precursor for?

Back 55

Glutamate
Glutamine, Proline, Arginine

Front 56

3-phosphoglycerate gives rise to what?
What is this a precursor for?

Back 56

Serine
Glycine, Cysteine

Front 57

Oxaloacetate gives rise to what?
What is this a precursor for?

Back 57

Aspartate
Methionine, Threonine, Lysine

Front 58

What is threonine the precursor for?
What else can form this product?

Back 58

Isoleucine
Pyruvate

Front 59

What does pyruvate give rise to?

Back 59

alanine, valine, leucine, isoleucine

Front 60

Phosphoenolpyruvate and erythrose-4-phosphate produces _____, which is converted to _____.
What is this last the precursor for?

Back 60

Shikimate
Chorismate
Tryptophan, Tyrosine, Phenylalanine

Front 61

What is phenylalanine the precursor for?

Back 61

Tyrosine

Front 62

What does ribose-5-phosphate give rise to?

Back 62

Histidine

Front 63

Elastin is rich in small, _____ _____ residues.
How much of the elastin contains these residues?
What are these residues?

Back 63

nonpolar aliphatic
1/3
Proline, alanine, valine, leucine, isoleucine

Front 64

What does elastin contain a small amount of?
What does it lack?

Back 64

Hydroxyproline
Hydroxylysine

Front 65

What are some characteristics of elastin?

Back 65

Rubbery connective tissue
Stretches to several times their normal length
Found in skin, ligaments, and artery walls

Front 66

What is the polypeptide subunit of elastin fibrils?

Back 66

Tropoelastin

Front 67

Elastin fibers are formed as a three-dimensional network of cross-linked polypeptides. The cross-links involve _____ and _____ _____ residues, which are covalently linked to produce a _____ cross-link.

Back 67

Lysine
Oxidized lysine (allysine)
Desmosine

Front 68

The oxidation of lysine residues in both collagen and elastin is an extracellular process catalyzed by _____ _____.

Back 68

Lysyl oxidase (requires copper)

Front 69

What two amino acids contain sulfur side chains as their R group?

Back 69

Cysteine
Methionine

Front 70

The _____ amino acids tend to repel the aqueous environment and, therefore, reside predominantly in the _____ of the protein.
What do these types of amino acids lack?

Back 70

Hydrophobic (non-polar)
Interior
Cannot ionize or H bond

Front 71

The _____ amino acids tend to interact with the aqueous environment, are often involved in the formation of _____, and are predominately found on the _____ surfaces proteins or in the reactive centers of enzymes.

Back 71

Hydrophilic (polar)
H-Bonds
Exterior

Front 72

What are the non-polar (hydrophobic), aliphatic R group amino acids?

Back 72

Alanine, Valine, Leucine, Isoleucine, Glycine, Proline

Front 73

What are the aromatic generally non-polar R group amino acids?

Back 73

Phenylalanine, Tyrosine, Tryptophan

Front 74

What are the hydrophilic polar uncharged R group amino acids?

Back 74

Serine, Threonine, Cysteine, Methionine, Asparagine, Glutamine

Front 75

The polarity of cysteine and methionine is contributed by their sulfur atom and that of _____ and _____ as their amide group.

Back 75

Asparagine
Glutamine

Front 76

What are the negatively charged R groups?
Are they acidic or basic?

Back 76

Aspartic Acid, Glutamic Acid
Acidic

Front 77

What are the positively charged R groups?
Are they acidic or basic?

Back 77

Lysine, Arginine, histidine
Basic

Front 78

What is the sequence of amino acids linked together by a covalent peptide bond?

Back 78

Primary structure of proteins

Front 79

What is the spatial arrangement of a portion of a polypeptide chain determined by amino acids present or the primary structure?
what are the common types?

Back 79

Secondary structure
alpha-helix, beta-pleated sheets, beta-hairpin turns

Front 80

What refers to the irregular folding of a polypeptide chain - the overall three dimensional conformation of polypeptide?

Back 80

Tertiary structure of proteins

Front 81

What refers to the spatial arrangement of subunits in a protein that consists of more than one polypeptide chain.
What are two examples of these?

Back 81

Quaternary structure of proteins
Hemoglobin and antibody molecules

Front 82

What is the best method for determining the three-dimensional structure of a protein?

Back 82

X-ray diffraction

Front 83

The hydroxylation of _____ and _____ residues in collagen requires vitamin C and oxygen.

Back 83

Proline Lysine

Front 84

Callagen is _____ glycine, _____ proline, and _____ alanine.
What is also present in smaller amounts?

Back 84

35%
21%
11%
Hydroxyproline and Hydroxylysine

Front 85

What is the basic structural unit of collagen?
What is special about this component and what is it secreted from?

Back 85

Tropocollagen
Longest known protein formed from procollagen
Secreted from fibroblasts

Front 86

Tropocollagen is also present in _____, which is a component of reticular fibers.

Back 86

Reticulin

Front 87

mature collagen _____ aromatic and Sulfur-containing amino acids.

Back 87

Lacks

Front 88

Where is collagen most important in function for the body?

Back 88

Tendons, Bone and Cartilage

Front 89

_____ and _____ fibers make up the stroma of all lymphoid tissues except the _____.

Back 89

Collagen
Reticular
Thymus

Front 90

What serves as a principal source of carbon for nonessential amino acids?
How many of these can be made?

Back 90

Carbohydrates
10 nonessential AA's

Front 91

What are the nonessesntial amino acids?

Back 91

Glutamate, Glutamine, Proline, Arginine, Serine, Glycine, Cysteine, Aspartate, Asparagine, Alanine, Tyrosine

Front 92

Nonessential amino acids can be synthesized from corresponding _____ acids, an _____ acid, and a specific _____ enzyme, and the coenzyme _____ _____; or by the process of _____.

Back 92

alpha-keto
alpha-amino
Transaminase
Pyridoxal phosphate

Amidation

Front 93

Although cysteine's carbon skeleton is formed from carbohydrates it still requires the essential amino acid _____ to supply the _____ group.

Back 93

Methionine
Sulfhydryl

Front 94

What essential amino acid is needed for optimal growth in infants and for nitrogen equilibrium in adults?

Back 94

Tyrosine

Front 95

What are the hydrophobic amino acids that contain aliphatic side chains?

Back 95

Valine, Leucine, Isoleucine

Front 96

What are the hydrophobic amino acids that contain aromatic side chains?

Back 96

Phenylalanine, Tyrosine, Tryptophan

Front 97

What are the end products of Tyrosin in the body?

Back 97

Dopamine, Thyroid hormones, melanin, norepi., and epi.

Front 98

What are the end products of tyrptophan in the body?

Back 98

Seratonin, melatonin, niacin, NAD and NADP

Front 99

When the enzyme that catalyzes the transformation of phenylalanine to tyrosine is not active because of a hereditary defect, the serious disease known as _____ results.

Back 99

Phenylketonuria (PKU)

Front 100

The trimeric GTP binding proteins play a pivotal role in the signal transduction pathways for numerous _____ and _____.

Back 100

Hormones
Neurotransmitters

Front 101

What are the three subunits of a trimeric GTP binding protein?

Back 101

Alpha
Beta
Gamma

Front 102

What subunits of the GTP binding protein are bound to the membrane via attached lipid molecules?

Back 102

Alpha, Gamma

Front 103

What are the characteristics of the receptors for the GTP binding proteins?

Back 103

Proteins with seven transmembrane alpha-helices

Front 104

The binding of the hormone or neurotransmitter to the receptor causes _____ to replace ____ on the alpha subunit. As a result, the _____ subunit dissociates from the other two.

Back 104

GTP
GDP
Alpha

Front 105

What types of channels are activated by the action of the the beta and gamma subunits of GTP binding to the inner surface of membrances?
What about a membrane enzyme?

Back 105

Potassium channels
Adenylate Cyclase

Front 106

The _____ subunit of G protein activates adenylate cyclase.

Back 106

Alpha

Front 107

What activates protein kinase A?

Back 107

cAMP