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BioBioChem MCAT > Bio1 Lesson 1: Biological Molecules and Enzymes > Flashcards

Bio1 Lesson 1: Biological Molecules and Enzymes Flashcards

(110 cards)

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1
Q

What is the key solvent for all biochemical reactions within cells?

A

Water

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2
Q

Is water large/small and polar/nonpolar?

A

Small, polar

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3
Q

What is hydrogen bonding?

A

Intermolecular bonding between H, F, O, or N

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4
Q

What is a solvation sell?

A

A shell of solvent surrounding a solute

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5
Q

What type of reaction uses water to break molecules?

A

Hydrolysis reactions

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6
Q

In what type of reaction is water a byproduct of combining molecules?

A

Dehydration/condensation reactions

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7
Q

Are lipids polar/nonpolar and hydrophilic/hydrophobic?

A

Nonpolar, hydrophobic

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8
Q

What are the 3 major roles of lipids?

A

1) Energy storage, 2) Cellular organization and structure (especially in membrane), 3) Precursor for vitamins and hormones

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9
Q

What are the 7 major classifications of lipids?

A

1) Fatty Acids, 2) Triacylglycerols/Triglycerides, 3) Phospholipids, 4) Glycolipids, 5) Steroids, 6) Terpenes and Eicosanoids, 7) Waxes

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10
Q

What are fatty acids and what are their roles?

A
  • Long chains of carbon truncated at one end by a carboxylic acid
  • Building blocks for complex lipids
  • Body fuel and components of cell membranes
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11
Q

Describe a saturated fatty acid and its function.

A
  • Only single bonds
  • Hang straight
  • Prefer to be stored when there is excess energy
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12
Q

Describe an unsatured fatty acid and its function.

A
  • One or more double/triple bonds
  • Kinked structure
  • Used for energy
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13
Q

Describe the structure and function of phospholipids.

A
  • Glycerol attached to 2 fatty accid chains + a polar phosphate group
  • Amphipathic
  • Structural component of membrane
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14
Q

Describe the structure and function of glycolipids.

A
  • Glycerol attached to 2 fatty acid chains + 1 or more carbohydrates (sugars)
  • Amphipathic
  • Found in membranes of myelinated cells
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15
Q

Describe the structure and function of steroids.

A
  • 4-ringed structures
  • Include some hormones, Vitamin D, cholesterol
  • Metabolic activity
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16
Q

Which classification of lipids is cholesterol part of and what is its function?

A
  • Steroids
  • Maintains membrane stability and fluidity
  • Precursor for steroid hormones
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17
Q

Describe the function of terpenes and eicosanoids.

A
  • Pigments
  • Paracrine signalling (communication with neighbour cells)
  • Some serve as local hormones
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18
Q

Describe the structure and function of waxes.

A
  • Ester linkage between a long-chain alcohol and a long-chain fatty accid
  • Protects from water loss, pathogens, and parasites
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19
Q

Describe the strucutre and function of lipoproteins.

A

-Have a lipid hydrophobic core (triacylglycerols and cholesterol)
surrounded by phospholipids and apoproteins
-Used to transport lipids in blood

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20
Q

What are the 4 classes of lipoproteins in decreasing size and ratio of lipid:protein?

A

1) Chylomicrons: dietary fat
2) VLDL (sticky on arteries)
3) LDL (sticky on arteries)
4) HDL: healthy/good cholesterol

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21
Q

Is Glycine a polar/nonpolar amino acid?

A

Nonpolar

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22
Q

Is Alanine a polar/nonpolar amino acid?

A

Nonpolar

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23
Q

Is Valine a polar/nonpolar amino acid?

A

Nonpolar

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24
Q

Is Leucine a polar/nonpolar amino acid?

A

Nonpolar

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25
Is Isoleucine a polar/nonpolar amino acid?
Nonpolar
26
Is Phenylalanine a polar/nonpolar amino acid?
Nonpolar
27
Is Tryptophan a polar/nonpolar amino acid?
Nonpolar
28
Is Methionine polar/nonpolar amino acid?
Nonpolar
29
Is Proline a polar/nonpolar amino acid?
Nonpolar
30
Is Serine a polar/nonpolar amino acid?
Polar
31
Is Cysteine a polar/nonpolar amino acid?
Polar
32
Is Threonine a polar/nonpolar amino acid?
Polar
33
Is Tyrosine a polar/nonpolar amino acid?
Polar
34
Is Asparagine a polar/nonpolar amino acid?
Polar
35
Is Glutamine a polar/nonpolar amino acid?
Polar
36
Is Aspartate a polar/nonpolar amino acid?
Polar
37
Is Glutamate a polar/nonpolar amino acid?
Polar
38
Is Histidine a polar/nonpolar amino acid?
Polar
39
Is Lysine a polar/nonpolar amino acid?
Polar
40
Is Arginine a polar/nonpolar amino acid?
Polar
41
Is Aspartate acidic/basic?
Acidic
42
Is Glutamate acidic/basic?
Acidic
43
Is Histidine acidic/basic?
Basic
44
Is Lysine acidic/basic?
Basic
45
Is Arginine acid acidic/basic?
Basic
46
Name the acidic amino acids.
- Aspartic acid | - Glutamic acid
47
Name the basic amino acids.
- Histidine - Lysine - Arginine
48
What are carbohydrates made from?
Carbon and water
49
What is the empirical formula of a carbohydrate?
CH2O
50
What is glucose?
A 6 carbon carbohydrate that can exist in one of two ring from anomers: alpha or beta
51
What is glycogen?
Glucose polymerized for storage
52
Describe the structure and function of glycogen.
- Branched glucose polymer that consists of alpha (trans) linkages in alpha (1-4) and (1-6) pattern - Used in animal storage
53
What do plants store glucose in?
Starch or cellulose
54
Describe the two forms of starch.
- Amylose: alpha (1-4) -- only straight chain | - Amylopectin: alpha (1-4) with some (1-6) -- minimal branches
55
Describe cellulose
Beta linkages with no branching
56
___ eat alpha linkages. ___ break beta linkages.
Animals, bacteria
57
Describe the structue of a protein.
Built from a chain of amino acid residues linked together by a peptide bond
58
How many total amino acids are there and how many are essential?
20, 9
59
Describe the structure of an amino acid.
Each amino acid has a central-alpha carbon linked to a: 1) Amino group (NH3+/NH2) 2) Carboxyl group (COOH/COO-) 3) Hydrogen 4) Sidegroup (R)
60
How does pH affect the charge of an amino acid?
- Lower pH (Higher acidity) : + charged amino acid | - Higher pH (Lower acidity): - charged area
61
What is the primary structure of proteins?
The amino acid sequence
62
What is the secondary structure of proteins?
Folding in polypeptide chain resulting from H-bonds - R group NOT involved - a-helix or B-pleated sheets
63
What is the tertiary structure of proteins?
3D shape resulting from R-group interactions: 1) H-bonds 2) Ionic/electrostatic interactions (+/- charges) 3) Vanderwaals force: london dispersion, dipole-dipole 5) Covalent bond: disulfide bonds (can link two amino acids that are far apart from each other to form a stable bridge)
64
What is the quaternary structure of proteins?
Proteins made up of more than 1 polypeptide chain - Homodimer: protein with 2 identical subunits - Heterodimer: protein with 2 non-identical subunits
65
Describe the two types of proteins.
1) Globular - Enzymes - Hormones - Membrane pumps and channels - Membrane receptors - Inter/intracellular transport and storage - Osmotic regulation - In the immune response 2) Structural - Maintain and add strength to cellular and matrix structure
66
Name all denaturing agents of proteins and what kinds of forces they disrupt.
- Heat -- disrupts all forces - Salt/change in pH -- disrupts ionic/electrostatic bonds - Organic solvents -- disrupt hydrophobic interactions - Urea -- disrupts hydrogen bonds - Mercaptoethanol -- disrupts disulfide bonds
67
Name and describe the 3 protein complexes.
1) Glycoproteins: - More than 50% protein - In plasma membrane 2) Proteoglycans: - More than 50% carbs and some protein - Extracellular matrix 3) Cytochromes: - Protein + prosthetic (covalently bonded) attached heme group - Enzymes in liver - Electron transport chain
68
Describe non-enzyme proteins and the 4 types.
Can bind to their targets but do NOT catalyze reactions 1) Membrane channels and receptors - In membrane and bind target/ligand 2) Transport proteins - Facilitate transfer of small molecules with or between cells 3) Antibodies - Specific to immune system - Bind and eliminate antigens 4) Motor proteins - Generate force for cellular movement
69
What are enzymes?
Catalyst proteins that increase the rate of biological processes by "lowering" the activation energy (Ea)
70
What is the susbtrate?
The reactant upon which an enzyme works | -Substrates are smaller than enzymes and bind non-covalently to its active site
71
What is the lock and key theory?
- Aka the active site model | - Substrate fits exactly into the active site
72
What is the induce fit model?
Active site of enzyme changes shape as the substrate binds
73
What are cofactors and coenzymes?
Non-protein components required for the enzyme to function as a catalyst
74
What are the types of cofactors?
1) Organic molecules (coenzymes) | 2) Inorganic moldecules (metal ions)
75
What is a prosthetic group?
A conenzyme covalently bound to enzyme
76
Are vitamins organic/inorganic?
Organic
77
Are minerals organic/inorganic?
Inorganic
78
Are coenzymes water-soluble?
Yes
79
What is a holoenzyme?
A complete catalytically active enzyme together with its bound coenzyme and/or metal ion
80
What is an apoenzyme?
The protein part of the enzyme
81
What are saturation kinetics?
As substrate concentration increases, rate of reaction also increases, but to a lesser and lesser degree until a maximum rate (Vmax) is reached
82
Is Vmax proportional/inversely proportional to to enzyme concentration?
Proportional
83
What is Km?
Substrate concentration when reaction rate is 1/2Vmax
84
Is Km proportional/inversely proportional to enzyme-substrate affinity?
Inversely proportional
85
What 3 factors is the enzymatic reaction rate closely associated with?
1) pH 2) Temperature 3) Substrate concentration
86
Describe enzyme inhibition and the 4 types of inhibitors (describe the binding site, the effect on Km, and the effect on Vmax).
Irreversible/reversible inhibition typically involving covalent bonds (lowering enzymatic activity) 1) Competitive inhibitors: - Often resemble substrate and bind to enzyme's active site - Km increases - Vmax is unchanged 2) Uncompetitive: - Bind at allosteric site - Bind to enzyme-substrate complex - Km decreases - Vmax decreases 3) Mixed: - Bind at allosteric site - Can bind to enzyme-substrate complex or enzyme alone - Km increases/decreaes - Vmax decreases 4) Non-competitive: - Bind at allosteric site - Change 3D shape - Reaction will not occur - Km is unchanged - Vmax decreases
87
When do negative feedback loops occur?
When one of the products downstream in a reaction series comes back and inhibits enzymatic activity of an earlier step
88
When do positive feedback loops occur?
When one of the products downstream in a reaction series comes back and increases the enzymatic activity of an earlier step
89
What is anabolism?
Synthesis of molecules for energy storage
90
What is catabolism?
The degredation of molecules for energy expenditure
91
Describe the function of a "proteolytic cleavage" control mechanism for enzyme regulation.
Inactive enzymes (zymogens) are irreversibly activated
92
Describe the function of a "reversible covalent modification" control mechanism for enzyme regulation.
Enzyme activation often via a modifier
93
Describe the function of a "control protein" control mechanism for enzyme regulation.
Control proteins/protein subunits associate with enzymes to activate/inhibit activity
94
Describe the function of an "allosteric interaction" control mechanism for enzyme regulation.
Allosteric regulators modify enzyme congifuration and activity by binding to specific sites on an enzyme
95
Describe the function of kinases (a type of enzyme).
Phosphorylation of target
96
Define the function of a phosphotase (a type of enzyme).
Dephosphorylation of target
97
Cofactors tend to be organic or inorganic?
Inorganic
98
Coenzymes tend to be orgnaic/inorganic?
Organic
99
What are some water-soluble vitamins?
B vitamins, vitamin C, biotin, folate
100
How does pH affect the rate of reaction of an enzyme?
Rate of reaction is highest at a neutral pH of about 7. The further the pH goes from neutral, the lower the rate of reaction. Rate of reaction is lowest when pH is extremely acid or extremely basic
101
How does temperature affect the rate of reaction of an enzyme?
Rate of reaction increases as temperature increases, until an optimal temperature of 37 degrees is reached. Then, the rate starts to decrease as the temperature increases
102
How does substrate concentration affect the rate of reaction of an enzyme?
As substrate concentration increases, rate of reaction increases (but to a lesser and lesser degree) until the Vmax is reached
103
What is the optimal temperature for the rate of reaction of an enzyme?
37 degrees
104
Do negative feedback loops maintain homeostasis?
Yes
105
Do positive feedback loops maintain homeostasis?
No
106
Describe properties of polar molecules
-Share electrons unequally -Have high electronegativities -Hydrophilic -Between S, N, O, P Examples: -Glucose -Proteins -DNA -RNA -Ions
107
Describe properties of nonpolar molecules
-Share electrons equally -Organic -Hydrophobic -C + H bonds Examples: Lipids (oils, fats, steroids)
108
What is the side chain for Glycine?
a single H group
109
What is the side chain for Alanine?
A methyl group (CH3)
110
What is the side chain for Cysteine?
SH

BioBioChem MCAT (4 decks)

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