Exam II Flashcards
(222 cards)
1
Q
What is the most abundant macronutrient in the body?
A
Protein
2
Q
What are some functions of proteins in the body?
A
Signaling, structure, immunity, transport, enzymes, fluid balance, and buffers
3
Q
What are hormones?
A
chemical messengers made in one part of the body that regulates another part.
4
Q
What are peptide hormones? Examples
A
chemical messengers that are made up of multiple amino acids. Examples: glucagon, PTH
5
Q
What are amino acid derivatives? Examples
A
Hormones that are made from a single amino acid. Examples: tyrosine creates thyroxine, histidine creates histamine, tryptophan creates serotonin
6
Q
What are cytokines? Examples
A
Small proteins that act as regulators of growth and differentiation. Ex: Interelukin-1 (IL-1), TNF-alpha, IL-6, CRP, IL-10
7
Q
What is the best indicator of inflammation?
A
C-reactive protein (CRP)
8
Q
What cytokine is produced during exercise?
A
IL-10. It is used as an anti-inflammatory.
9
Q
What are the two types of structural proteins?
A
Fibrous (collagen, elastin, keratin) and Contractile (actin and myosin)
10
Q
What are immunoproteins?
A
Y-shaped proteins that contain 4 peptides. They bind to antigens and inactivate them.
11
Q
Which class of immunoprotein is involved with allergies
A
IgE
12
Q
What do transport proteins do?
A
They combine with other substances and act as modes of transport through the body.
13
Q
What are some examples of transport proteins?
A
Albumin, hemoglobin, transferrin, and vitamin D-binding protein.
14
Q
What are enzymes?
A
They are biological catalysts that speed up a reaction by lowering the energy needed for that reaction to occur. They regulate metabolic pathways and are necessary for life.
15
Q
What biological necessity is attracted to proteins?
A
Water
16
Q
What can a protein deficiency lead to in terms of fluid balance?
A
It can cause fluid to leak into interstitial spaces, leading to edema.
17
Q
What can a protein deficiency be caused by?
A
Kidney disease, large wounds, liver disease, or MALNUTRITION
18
Q
What is Kwashiorkor?
A
Protein malnutrition
19
Q
What is a buffer?
A
A compound that prevents a change in pH.
20
Q
What acts as a buffer in red blood cells?
A
Hemoglobin
21
Q
When a base is added to a solution, what happens to the H+ concentration?
A
The H+ concentration decreases
22
Q
When a base is added to a solution, how does a protein act as a buffer?
A
The protein donates hydrogens
23
Q
When a base is added to a solution, which part of the protein donates a H+ ion?
A
The amino group
24
Q
What are amino acids?
A
They are the building blocks of proteins
25
How many amino acids are there? How many are essential/nonessential?
There are 20 amino acids with 9 of them being essential and 11 of them being nonessential
26
What dictates the structure of an amino acid?
The R group through its disulfide bridges, electrostatic interactions, and H-bonds.
27
What is an L-amino acid?
CORN clockwise, meaning COO-, R-group, amino group in a clockwise fashion
28
What is a D-amino acid?
CORN counterclockwise, meaning COO-, R-group, amino group in a counterclockwise fashion
29
Where are amino acids used in the body?
The liver and muscles
30
What new proteins are made in the liver?
Enzymes, plasma proteins, and acute phase proteins (inflammatory response)
31
What type of amino acids are found in muscles?
Branched chain amino acids only (valine, leucine, and isoleucine)
32
A deficiency in what proteins causes kwahiorkor?
Albumin and prealbumin
33
It is the most abundant plasma protein and is used to maintain osmotic presure, transport nutrients, and measure protein status (half-life of 2 weeks).
Albumin
34
What is prealbumin?
It is a transport protein and also acts to measure protein status (half-life of 2 days)
35
What does aliphatic mean?
To contain a hydrocarbon in the R group
36
What is being nonpolar synonymous with?
Being hydrophobic
37
What is being polar synonymous with?
Being hydrophilic
38
To be aromatic means?
To contain a 6 membered ring in the R group
39
In terms of amino acids, being acidic means what?
That the R group contains a carboxylic acid and it is negatively charged
40
In terms of amino acids, being basic means what?
That the R group contains N and it is positively charged
41
This amino acid is the only amino acid without a chiral carbon, found in high concentrations in collagen, nonpolar, aliphatic, uncharged, and is nonessential
Glycine
42
This amino acid is released from muscles during starvation, exercise, or after a high carb meal. It is also nonessential, nonpolar, aliphatic and uncharged
Alanine
43
It is a branched chain amino acid, nonpolar, aliphatic, uncharged, and essential.
Valine
44
What disease is the result of valine replacing glutamate in hemoglobin thereby causing it to fold incorrectly? Hint: It provides immunity to malaria.
Sickle Cell Anemia
45
It is an essential, nonpolar, aliphatic, uncharged branched chain amino acid that is found in high concentrations in globulins and albumins. Its partial degradation leads to HMG CoA, which is a precursor to cholesterol
Leucine
46
It is an essential nonpolar, aliphatic, uncharged, branched chain amino acid. It is also a structural isomer of leucine.
Isoleucine
47
This disease is a genetic deficiency of enzymes that are required to metabolize branched chain amino acids. Its symptoms include urine with the color, odor, and viscosity of maple syrup.
Maple syrup urine disease
48
It is an essential, nonpolar, aliphatic, uncharged amino acid. It contains sulfur and is a precursor for SAMe and cysteine.
Methionine
49
What is the function of SAMe in the body?
It methylates compounds
50
It is a nonessential, nonpolar, uncharged amino acid. It disrupts alpha helix and beta-pleated sheet structures and is found in high concentrations in collagen.
Proline
51
Why has gluten intolerance increased in recent years?
Food processors use more gluten now as an individual ingredient
52
What reduces gut permeability and inflammation in celiac patients?
Probiotics (Bifidobacterium and Lactobacillus GG)
53
It is an essential, nonpolar, aromatic, and uncharged amino acid. It is the precursor to tyrosine.
Phenylalanine
54
What is PKU?
It is a genetic disorder where individuals lack the enzymes necessary to metabolize phenylalanine.
55
What is the treatment for PKU?
Avoid any foods that have phenylalanine in them.
56
What is cystic fibrosis?
It is a genetic disorder where individuals are missing 1 phenylalanine in proteins that regulate the transport of chloride ions across cell membranes. Causes a build up of mucus in various areas.
57
It is an essential, nonpolar, aromatic, uncharged amino acid. It is the precursor to serotonin, melatonin, and niacin
Tryptophan
58
It is a nonessential, polar, uncharged amino acid. It is important in the active site of enzymes and is capable of H-bonding
Serine
59
It is an essential, polar, uncharged amino acid. It is also a site of phosphorylation in protein regulation.
Threonine
60
It is a nonessential, polar, uncharged amino acid. It has a thiol (-SH) group that acts as a proton donor in glutathione (antioxidant properties). It is also important in proteins that participate in redox and for cross-linking proteins through disulfide bonds.
Cysteine
61
It is a nonessential, polar, aromatic, uncharged amino acid. It is a precursor for thyroid hormones, melanin, and catecholamines.
Tyrosine
62
What are some examples of catecholamines?
Dopamine, Norepinephrine, and Epinephrine
63
It is a nonessential, polar, uncharged amino acid. It is found at teh beginning and end of alpha helices because of H-bonding in R groups. Forms acrylamide with sugar at high temperatures.
Asparagine
64
It is a nonessential, polar, uncharged, amino acid. It is the most abundant free amino acid in the body and is the principal N carrier in the body
Glutamine
65
It is a nonessential, acidic amino acid. it is important for transporting electrons in the electron transport chain.
Aspartate
66
What is the common name for Aspartame?
Nutrasweet
67
What is Aspartame composed of?
Aspartate and phenylalanine
68
When Aspartame is metabolized, what occurs?
It is broken down into aspartate, phenylalanine, and methanol. Methanol is then broken down into formaldehyde then to formate and finally CO2 and H2O.
69
Is aspartate an excitotoxin?
Yes
70
It is a nonessential, acidic amino acid. It excites neurons and is the precursor for GABA (neurotransmitter that quiets excited neurons)
Glutamate
71
Where is most of the glutamate in the body used?
90% of the glutamate in the body is used by cells lining the small intestine.
72
It is an essential, basic amino acid. It is important in collagen formation, used in signaling, precursor for carnitine (carrys long-chain fatty acids to mitochondria), and has supplements that are used to prevent oral herpes.
Lysine
73
What are amyloids and what disease are they associated with?
They are normal cellular proteins that unravel and stick together. They are associated with Alzheimer's disease
74
What are tangles and what disease are they associated with?
They are microtubules that become phosphorylated and behave unnaturally. They are associated with Alzheimer's disease
75
In Alzheimer's disease beta-amyloid plaque acts as_____to acetylcholinesterase resulting in _____ acetylcholine.
Inducer, less. Physical symptoms of this includes an impairment in sensory perception and decreased attention sustainability
76
A compound called CLR01, which binds lysine and unglues amyloids is a potential treatment for what disease?
Alzheimer's disease
77
It is a nonessential, basic amino acid. It is a precursor for nitric oxide.
Arginine
78
What compound is produced by white blood cells during acute and chronic inflammation?
Nitric Oxide
79
It is an essential and basic amino acid. It is a precursor for histamine and is important in hemoglobin and myoglobin.
Histidine
80
Which of the following amino acids is the precursor to dopamine?
Tyrosine
81
What is the acronym for the essential amino acids?
PVT MT HILL
82
What are the two uses for amino acids in the body?
Glucogenic and Ketogenic
83
Amino acids that are used for glucogenic purposes are...
Used to make glucose, if necessary
84
Amino acids that are used for ketogenic purposes are...
Turned into Kreb's cycle intermediate, ketone bodies, or fatty acids if in excess
85
What is the product produced by glucogenic processes?
Pyruvate
86
What is the product produced by ketogneic processes?
Acetyl CoA
87
Which amino acids are ketogenic?
Leucine and Lysine
88
What amino acids are glucogenic and ketogenic?
Tyrosine, Isoleucine, Phenylalanine, and Tryptophan
89
What types of materials are considered coenzymes?
Organic components, vitamins
90
What types of materials are considered cofactors?
Inorganic components, minerals (IRON)
91
Amino acids are synthesized by...
Deamination or transamination
92
Why are essential amino acids important?
They are needed in order to make protein in the body. Need to obtain the essential amino acids within at least 24hr period or else the body will start to break down proteins
93
What is the free amino acid pool?
It refers to an amount of amino acids (~150g) that are free within the body at any given time.
94
What is the fate of free amino acids within the body determined by?
Hormones and carbohydrate and fat intake.
95
Cell components are recycled by the lysosome if:
They are damaged by free radicals/oxidized, misfolded, or no longer needed
96
Amino acids have these three functional groups attached to their alpha carbon.
An amino group, carboxyl group, and an R group
97
pK1 refers to the removal of H from the...
Carboxyl group
98
pK2 refers to the removal of H from the...
Amino group
99
pKr refers to the removal of H from the...
R group
100
If pH is below both pK1 and pK2 both groups are...
Fully protonated
101
If pH is above pK1, but below pK2 or vice versa...
The H on the acid group (pK1) is lost and the H on the amino group (pK2) is still attached. This is referred to as a Zwietterion.
102
If pH is above both pK1 and pK2 both groups are...
Fully deprotonated
103
What is the general rule of thumb for pKs?
Any pKs above the pH are protonated and any pKs below pH are deprotonated
104
What is the isoelectric point?
The point where an amino acid or protein is neutral (Zwitterion).
105
When calculating the isoelectric point for amino acids with pK1 and pK2 only you...
Average pK1 and pK2
106
When calculating the isoelectric point for aminio acids with pK1, pK2, and pKr you...
Average pKr and the closest pK
107
Amino acids can act as...
Acids and Bases, when the pH warrants it.
108
What are the four levels of protein structure?
Primary, Secondary, Tertiary, and Quaternary
109
Which level of protein structure includes covalent bonds and is just a sequence of amino acids?
Primary
110
What type of bonds are formed via condensation/dehydration and are trans in nature?
Peptide bonds
111
What is the difference between a peptide and a protein?
Peptides are shorter (10-100 amino acids=polypeptide) than a protein (>100 amino acids)
112
Macronutrients are all synthesized by what kind of reaction?
Dehydration (1H2O removed for each peptide bond)
113
Which level of protein strucutre has a spatial arrangement of atoms around a polypeptide backbone, are stabilized by noncovalent interactions, and contain alpha-helices, beta-pleated sheets, and beta-bends?
Secondary
114
What is an alpha helix?
Repeating units of protein structure stabilzed by H-bonding every 4 amino acids
115
What is a beta-pleated sheet?
A polypeptide H-bonded to another polypeptide aligned in parallel or antiparallel fashion.
116
What are beta bends?
Reverse direction of polypeptide chain to fold compactly in globular structures
117
Which level of protein structure has a 3-D arrangement, is a folding of a single polypeptide chain, and is influenced by R-groups?
Tertiary
118
Which level of protein structure is a grouping of two or more peptide chains?
Quaternary
119
During protein synthesis, which class of proteins aid in protein folding?
Chaperone proteins
120
What happens to a protein when it becomes unfolded?
Its secondary, tertiary, and quaternary structure change. This disrupts the alpha helix and beta pleated sheet as well as causes an overall loss of protein activity.
121
What can cause protein unfolding?
Heat, strong acids/bases, and mechanical forces
122
Which of the following amino acids are normally found in the interior of globular proteins?
Valine
123
What are the classes of protein shape?
Globular and Fibrous
124
These proteins are highly folded, water soluble proteins, with a hydrophobic core, hydrophilic outside, and are easily denatured.
Globular proteins
125
It is the hemeprotein in the heart and skeletal muscle that acts as the oxygen carrier for aerobic metabolism
Myoglobin (1 polypeptide, 1 heme=1 Fe=1 O2 molecule
126
It is found exclusively in red blood cells and is used to transport oxygen from the lungs to tissues
Hemoglobin (4 polypeptides, 4 hemes=4 Fe=4 O2 molecules)
127
Which type of hemoglobin is considered to be in the relaxed state?
Oxyhemoglobin
128
Which type of hemoglobin is considered to be in the taut state?
Deoxyhemoglobin
129
A decrease in pH favors which type of hemoglobin?
Deoxyhemoglobin
130
An increase in oxygen or pH favors which type of hemoglobin?
Oxyhemoglobin
131
What determines the degree of saturation of oxygen-binding sites in hemoglobin?
The partial pressure of oxygen
132
Which molecule binds oxygen at low concentrations and releases it in response to oxygen demand?
Myoglobin
133
Which molecule undergoes cooperative binding (binding of oxygen at one site increases the affinity for oxygen at additional sites if present)?
Hemoglobin
134
What is the lifespan of a red blood cell?
120 days
135
What occurs during hemoglobin degradation?
The cell membrane of red blood cells becomes fragile and bursts. Hemoglobin is released and phagocytized by macrophages, iron is released and transported in the blood by transferrin, and porphyrin ring is converted to bilirubin by macrophages.
136
What is jaundice?
Is a condition caused by large concentrations of bilirubin in extracellular fluid.
137
What is hemolytic jaundice caused by?
Excessive destruction of red blood cells. High levels of free (unconjugated) bilirubin adn urobilinogen in blood
138
What is obstructive jaundice caused by?
Obstruction of the bile duct and liver damage. High levels of conjugated bilirubin in the blood
139
What does allosteric mean?
Other site
140
What is 2,3-bisphosphoglycerate?
It is an intermediate in glycolysis, found in equal concentration as hemoglobin is in red blood cells. Binds to deoxyhemoglobin, decreasing oxygen affiinity and allows hemoglobin to release oxygen at concentrations in tissues
141
What does carbon monoxide do?
Reversibly binds iron in heme, which has a 250 times greater affinity for CO than O2 and shifts the O2 dissociation curve, thereby no longer allowing O2 to be released.
142
Which oxygen is the hardest to bind?
Oxygen 1
143
These are insoluble, highly cross-linked, insoluble proteins that play a structural role in the body
Fibrous proteins
144
What is the most abundant protein in the body?
Collagen
145
What are the three collagen types?
Network-forming, fibril-forming, and fibril-associated
146
What are the four main amino acids that compose collagen?
Glycine, proline, hydroxylglycine, and hydroxylproline
147
What two things are required to synthesize hydroxylglycine and hydroxylproline?
Vitamin C and iron
148
What is lysyl oxidase?
It is a copper-dependent enzyme that deaminates lysine, which forms reactive aldehydes that condense with lysine or hydroxylysine on neighboring collagen
149
What disease is caused by Vitamin C deficiency and has symptoms such as corkscrew hairs and bleeding gums?
Scurvy
150
What enzyme degrades collagen?
Matrix metalloproteinases (MMPs)
151
What is lysyl oxidase used for?
Crosslinking of collagen and elastin
152
This protein is a rubber-like connective tissue found in lungs, large arteries, and elastic ligaments
Elastin
153
What enzymes degrade elastin?
Neutrophil elastase
154
What does alpha1-antitrypsin do and why is it important?
It binds and inhibits neutrophil elastase, thereby preventing the breakdown of elastin. It is important for maintaining lung elasticity.
155
Which protein is mostly triple helical and virtually insoluble in water?
Collagen
156
What amino acid is not found in high concentrations in collagen?
Valine
157
What is the most common type of collagen in the human body?
Type I
158
Which posttranslational modification is extremely important in collagen structure?
Hydroxylation
159
Which is more important to providing tensile strength associated with collagen structure? Covalent interactions or Noncovalent interactions.
Covalent interactions
160
What is an apoenzyme?
The protein part of an enzyme only. It is missing a cofactor/coenzyme
161
What is a holoenzyme?
A complete (active) enzyme. The protein and the cofactor/coenzyme
162
What is a zymogen?
An enzyme precursor (inactive)
163
What are the six classes of enzymes?
Oxidoreductase, transferase, isomerase, hydrolase, lyase, and ligase
164
This enzyme is involved in the addition or removal of H and requires coenzymes (NAD+ and FAD)
Oxidoreductase
165
This enzyme transfers a functional group from one molecule to another.
Transferase
166
This enzyme rearranges functional groups on one molecule only.
Isomerase
167
This enzyme causes hydrolysis reactions, breaks water bonds, and are typically classified as digestive enzymes.
Hydrolase
168
This enzyme cleaves various carbon bonds.
Lyase
169
This enzyme joins bonds between carbon and other elements. This enzyme requires ATP to form bonds and typically has a free phosphate ion at the end of the reaction
Ligase
170
Which enzyme class moves a phosphate from ATP onto glucose to make glucose-6-P and ADP?
Transferase
171
How do enzymes work?
They contain an active site that reacts with a specific substrate.
172
What two subsites compose the active site of an enzyme?
The binding site and catalytic site
173
What does the binding site of an enzyme do?
It holds the substrate in the proper place through weak noncovalent interactions.
174
What is significant about the catalytic site of an enzyme?
It is where the reaction usually occurs
175
What are the two active site models that scientists have created?
The lock and key model and the induced-fit model (has a flexible active site)
176
What is the turnover rate in terms of enzymes?
It is the concentration of substrate converted to product per enzyme molecule
177
It is the minimum amount of energy that must be input to a chemical system to cause a reaction
Activation energy
178
It is the state corresponding to the highest energy point in a catalytic reaction in which the substrate is no longer a substrate, but also not yet a product.
Transition state
179
How do enzymes speed up reactions?
They decrease the activation energy
180
This term refers to the number of reactions catalyzed by enzyme per second.
V0
181
This term refers to the point in time where the enzyme is completely saturated with substrate
Vmax
182
This term refers to the affinity for binding or the amount of substrate required for 50% of the enzyme to be bound
Km (Michaelis constant)
183
A smaller Km means there is a ____ affinity to bind the substrate, while a larger Km means there is a ____ affinity to bind the substrate
High, low
184
What are some factors that affect enzyme activity?
Enzyme/substrate concentrations, cofactors/coenzymes, effectors, temperature, pH
185
What is the optimum temperature for enzyme activity? What happens if this temperature is exceeded?
35-40 degrees C. If this temperature is exceeded enzymes begin to denature
186
What is an inhibitor in terms of enzymes?
Anything that decreases enzyme activity
187
What is an irreversible inhibitor?
It decreases enzyme activity through covalent bonding and must make more enzyme to make product
188
What is a reversible inhibitor?
It decreases enzyme activity through noncovalent interactions, can dissociate, and can also be competitive or noncompetitive
189
A competitive inhibitor will compete with the substrate for the what?
Active site
190
An inhibitor that binds to a different site (allosteric site) than the substrate (active site) is considered to be a what?
Noncompetitive inhibitor
191
Enzyme regulation occurs through which three methods?
Regulation of allosteric enzymes, covalent modifications, and induction and repression of enzyme synthesis
192
These are very fast regulatory enzymes that are rate-limiting and can be negative or positive effectors.
Allosteric enzymes
193
The process of adding or removing phosphate groups to serine, threonine, or tyrosine on the enzyme.
Covalent Modification
194
We consume ~100 grams of ____ protein per day from animal products and plant proteins.
Exogenous
195
We get ~300 grams of ____ protein from digestive enzymes and sloughed cells
Endogenous
196
Exogenous and Endogenous proteins are digested by what?
Proteases
197
Does protein digestion occur in the mouth?
No
198
How does protein digestion occur in the stomach?
HCl is released from parietal cells in response to gastrin. It denatures secondary, tertiary, and quaternary protein structures.
199
What does protein digestion in the stomach do to pepsinogen?
It converts it into its active state pepsin.
200
What type of enzyme is pepsin?
It is an endopeptidase, which digests internal peptide bonds.
201
How does protein digestion occur in the small intestine?
Chyme is released into the small intestine, which stimulates the release of secretin and CCK, which stimulates the release of bicarbonate, water, electrolytes, and zymogens from the pancreas
202
What are the products of pancreatic endopeptidase digestion?
Peptides and amino acids
203
What are the products of pancreatic exopeptidase digestion?
Amino acids only
204
What do pancreatic and brushborder enzymes digest proteins into?
Free amino acids, dipeptides, and tripeptides
205
Does protein digestion occur in the large intestine?
No
206
What are the steps to free amino acid absorption?
Sodium binds to the carrier protein. The amino acid then binds to the carrier protein. The carrier protein then releases sodium and the amino acid inside of the enterocyte. Finally sodium is pumped out of the enterocyte and potassium is pumped in using ATP
207
How are dipeptides and tripeptides absorbed?
Via active transport using PEPT1 transport protein
208
What is faster: Peptide absorption or free amino acid absorption?
Peptide absorption
209
What are the steps to peptide absorption?
Hydrogen binds to PEPT1. Di- or tripeptide then binds to PEPT1. PEPT1 then releases the hydrogen and peptide inside the enterocyte. Hydrogen is then pumped back into the small intestine lumen in exchange for sodium. Sodium is then pumped out of the cell while potassium is pumped in using ATP. Petidase then digests the amino acids into free amino acids.
210
Why are amino acids necessary in enterocytes?
They make energy, proteins for new enterocytes, apoproteins for lipoproteins, new digestive enzymes, hormones, nucleotides, and N-containing compounds
211
What do enterocytes do with extra amino acids?
It is transported through the basolateral membrane into the interstitial fluid by passive and facilitated diffusion.
212
Which cells of the stomach secrete pepsinogen?
Chief cells
213
What do endopeptidases create in the stomach?
Large polypeptides, oligopeptides, and free amino acids
214
What are some examples of pancreateic zymogens?
Trypsinogen, chymotrypsionogen, procarbosypeptidase, proelastase.
215
What is the function of enteropeptidase?
To convert tyrpsionogen to trypsin
216
What is the function of trypsin in protein digestion?
It converts pancreatic zymogens into their active form. Without it most protein digestion would not occur.
217
What is the only exopeptidase that we have?
Carboxypeptidase (zinc dependent)
218
What terminal end does carboxylpeptidase start digesting proteins?
Carboxy- or C-terminal
219
What are the brushborder exopeptidases?
Aminopeptidase and Dipeptidase (magnesium dependent)
220
What terminal end does aminopeptidase start digesting proteins?
Amino or N-terminal
221
Where does dipeptidase digest peptide bonds?
In between 2 amino acids in a dipeptide
222
What is the ONLY substance that crosses the basolateral membrane?
Free amino acids
