PY411 Flashcards
(241 cards)
1
Q
What is the difference between a drug and a medicine?
A
A drug is the active pharmaceutical ingredient (API), whereas a medicine includes the drug combined with excipients in a specific dosage form.
2
Q
Why do we need dosage forms?
A
Drugs are often in tiny powder form (mg or µg); dosage forms bulk them up with excipients, improve stability, ensure accurate dosing, and enable administration.
3
Q
Why do we need different dosage forms?
A
Different clinical conditions, patient types, routes of administration, and physicochemical properties of drugs require various forms.
4
Q
List three examples of oral dosage forms.
A
Tablets, capsules, suspensions.
5
Q
Name three routes of administration besides oral.
A
Parenteral (injection), topical (skin), pulmonary (inhalation).
6
Q
Give examples of paracetamol dosage forms.
A
Tablets, effervescent tablets, orodispersible tablets, capsules, oral suspensions, suppositories, infusion solutions.
7
Q
What are the key components of a tablet?
A
API, diluents (e.g. lactose), binders, disintegrants, lubricants, coatings.
8
Q
What is the difference between a solution and a suspension?
A
Solutions have drugs dissolved (transparent), while suspensions have finely divided, insoluble particles (opaque; must be shaken).
9
Q
What is an elixir?
A
A sweetened oral solution containing both water and alcohol.
10
Q
What is a syrup?
A
A sweetened aqueous solution of a drug in sucrose.
11
Q
What are the advantages of oral administration?
A
Natural, uncomplicated, convenient, and perceived as safe.
12
Q
What are the disadvantages of oral administration?
A
Slow response, risk of irregular absorption, and drug destruction by stomach acid or enzymes.
13
Q
Name three transmucosal oral routes.
A
Sublingual, buccal, oromucosal.
14
Q
What are suppositories used for?
A
Local effects (e.g. constipation) or systemic effects (e.g. paracetamol in children).
15
Q
Name three types of parenteral injection.
A
Intravenous (IV), intramuscular (IM), subcutaneous (SC).
16
Q
What are the types of injectables?
A
Sterile solutions, suspensions, emulsions, and implants.
17
Q
What semisolid forms are used for skin application?
A
Creams, ointments, gels (texture and base affect drug release).
18
Q
List pulmonary delivery devices.
A
Metered dose inhalers, dry powder inhalers, nebulisers, soft mist inhalers.
19
Q
What are examples of nasal and ocular dosage forms?
A
Nasal drops/sprays, ophthalmic solutions/ointments (must be sterile).
20
Q
What are vaginal dosage forms?
A
Tablets, foams, gels, suspensions, pessaries, rings.
21
Q
What defines a functional group in a drug molecule?
A
A specific atom arrangement with characteristic reactivity and physical properties that affect the drug’s behaviour.
22
Q
What three major properties are affected by functional groups?
A
Electronic effects, solubility effects, steric effects.
23
Q
How do functional groups influence solubility?
A
They determine water or lipid solubility depending on their polarity, hydrogen bonding, and adjacent groups.
24
Q
What are examples of water-soluble functional groups?
A
Hydroxyl (OH), carboxylic acid (COOH), amine (NH2).
25
What are examples of lipid-soluble functional groups?
Aromatic rings, alkyl chains, halogens.
26
What are electronic effects?
Functional groups can donate or withdraw electrons through resonance or inductive effects.
27
What is resonance?
Delocalization of electrons across atoms with adjacent double bonds or lone pairs.
28
What is inductive effect?
Electron withdrawal or donation based on electronegativity differences of atoms/groups.
29
What are electron-donating groups?
Groups like OH or NH2 that push electrons (nucleophilic).
30
What are electron-withdrawing groups?
Groups like NO2 or CF3 that pull electrons (electrophilic).
31
What are steric effects?
The size of a functional group affects molecular shape, binding, metabolism, and selectivity.
32
Why are steric effects therapeutically useful?
They can enhance target selectivity, improve binding, and slow down metabolism.
33
How does the structure of tamoxifen affect solubility?
Contains both polar (hydroxyl) and nonpolar (aromatic rings) regions; moderately lipid-soluble.
34
What textbook chapters should be studied for functional groups?
Pharmaceutical Chemistry (Watson): Ch. 2 (Hydrocarbons), Ch. 4 (Nitrogen compounds), Ch. 5 (Oxygen & Sulphur groups).
35
Example MCQ: What route does nicotine gum use?
Oromucosal.
36
Example SAQ: Why is a drug formulated into a medicine?
To allow accurate dosing, stability, handling, absorption, and acceptability in clinical use.
37
What are physicochemical properties of a drug?
Molecular formula, molecular weight, physical state, colour, odour, solubility, pKa, log P, particle size, melting/boiling points, vapour pressure, and density.
38
Why are physicochemical properties important?
They determine how a drug is formulated, how it dissolves, how it crosses membranes, and how it produces its clinical effect.
39
What are crystalline solids?
Solids with a regular, repeating arrangement of molecules or atoms and sharp melting points.
40
What are amorphous solids?
Solids lacking long-range order with randomly arranged molecules; they are usually more soluble than crystalline forms.
41
What is polymorphism in drugs?
The existence of multiple crystalline forms of the same drug, each with different packing patterns and physicochemical properties.
42
Why is polymorphism important in pharmacy?
Different polymorphs may have different solubility, melting point, density, and bioavailability — affecting formulation and therapeutic performance.
43
What is a metastable polymorph?
A less stable form that may offer better solubility and faster dissolution but may convert to a more stable form over time.
44
What are crystal hydrates?
Crystalline forms containing water molecules in fixed molar ratios; e.g., monohydrates, dihydrates.
45
How do hydrates differ from anhydrous forms?
Hydrates typically dissolve more slowly and have higher melting points and lower solubility than anhydrous forms.
46
What is crystal lattice energy?
Energy released when constituent atoms are arranged in the crystal lattice. High lattice energy reduces solubility and increases melting point.
47
What is solubility?
The maximum amount of solute that dissolves in a solvent to form a saturated solution at equilibrium.
48
What is dissolution?
The process of a solute entering solution from its solid form, typically a rate-limiting step in drug absorption.
49
What is a saturated solution?
A solution where the maximum possible amount of solute has dissolved, and an equilibrium exists between dissolved and undissolved solute.
50
Which factors affect solubility of a drug?
Molecular weight, shape, lipophilicity (log P), ionisation (pKa), and crystal lattice energy.
51
How is wettability measured?
By the contact angle between a solid and water; lower angles mean better wettability and faster dissolution.
52
What contact angle indicates good wettability?
Less than 90° (e.g., lactose has 30°).
53
What is deliquescence?
Absorption of water from the atmosphere by an amorphous solid until it dissolves completely.
54
What is the Noyes-Whitney equation?
dC/dt = D*A*(Cs - C)/h; describes how dissolution rate is affected by surface area, diffusion coefficient, solubility, and diffusion layer thickness.
55
What is the relationship between particle size and dissolution rate?
Smaller particles have larger surface area, increasing dissolution rate.
56
What is a eutectic mixture?
A solid dispersion of a drug with a soluble carrier (e.g., griseofulvin with succinic acid) to enhance solubility and bioavailability.
57
What is the effect of melting point on solubility?
Higher melting point generally corresponds to lower solubility.
58
What is Fick’s First Law of Diffusion?
dC/dt = -D*(dC/dx); diffusion rate is proportional to the concentration gradient.
59
What is the difference between solubility and dissolution rate?
Solubility is the maximum concentration a drug can achieve in solution. Dissolution rate is how fast it reaches that concentration.
60
What is log P?
The partition coefficient of a drug between octanol and water; a measure of lipophilicity.
61
What does a high log P indicate?
The drug is highly lipophilic and may have better membrane permeability but lower solubility.
62
What is log D?
The distribution coefficient that accounts for ionised and unionised species of a drug at a specific pH.
63
What does PSA (polar surface area) indicate?
The surface area of polar atoms (N, O, and H). Lower PSA (<90 Ų) is associated with better cell membrane permeability.
64
What is bioavailability?
The rate and extent to which a drug reaches systemic circulation and is available at the site of action.
65
What is absolute bioavailability?
(AUC oral / AUC IV) × 100; compares oral to IV route, with IV assumed to be 100% bioavailable.
66
What is relative bioavailability?
(AUC test / AUC reference) × 100; compares different formulations of the same drug, not necessarily to IV.
67
What is AUC?
Area under the plasma concentration-time curve; a measure of total drug exposure over time.
68
What affects oral bioavailability?
Drug release from dosage form, solubility, membrane permeability, pre-systemic metabolism (first-pass effect).
69
What is the therapeutic window?
The plasma concentration range in which a drug is effective without being toxic.
70
What are Cmax and Tmax?
Cmax is the peak plasma concentration; Tmax is the time it takes to reach it.
71
What are sink conditions?
Conditions where the drug concentration in solution remains far below saturation, 3x saturated amount, promoting continuous dissolution.
72
What is meant by ionisation of a drug?
Conversion of a molecule to charged form depending on pH and pKa; affects solubility and membrane permeability.
73
What is the Henderson-Hasselbalch equation for weak acids?
pH = pKa + log([A-]/[HA])
74
What is the Henderson-Hasselbalch equation for weak bases?
pH = pKa + log([B]/[BH+])
75
What is pKa?
The pH at which a molecule is 50% ionised; indicates acid/base strength.
76
What is the typical pKa range for acidic drugs?
pKa ~1–5
77
What is the typical pKa range for basic drugs?
pKa ~7–10.5
78
How does pH affect solubility of acidic drugs?
Acidic drugs are more ionised (and soluble) at higher pH.
79
How does pH affect solubility of basic drugs?
Basic drugs are more ionised (and soluble) at lower pH.
80
What is the ionic product of water (Kw)?
Kw = [H+][OH-] = 1 × 10^-14 at 25°C; pKw = 14
81
What is the role of buffers in formulations?
To resist pH change and maintain drug stability and solubility in solution.
82
What is the Henderson-Hasselbalch equation used for in pharmacy?
To calculate the ionisation state of drugs and inform formulation decisions.
83
What is potentiometry?
Measurement of voltage to determine ion concentration, often used in titrations and pH measurement.
84
What does the glass electrode measure?
Hydrogen ion concentration (pH) using a pH-sensitive membrane and a reference electrode.
85
What are the components of a typical titration setup?
Burette, pipette, conical flask, indicator, titrant solution, analyte solution.
86
What is the importance of titrations in pharmacy?
Used to determine the concentration of active ingredients and validate formulations.
87
What is a zwitterion?
A molecule with both positive and negative charges but no net charge (e.g., amino acids at isoelectric point).
88
What does a log P of >5 suggest?
Poor water solubility and potential absorption issues.
89
What is the relationship between pKa and solubility?
Drugs are more soluble in pH environments where they are ionised.
90
What is meant by 'salting out'?
Reduced solubility of a compound in a solution due to high ionic strength from added salts.
91
What is peptisation?
The breakdown of aggregates in suspension into smaller particles; affects suspension stability.
92
What factors influence drug absorption across membranes?
Lipid solubility, degree of ionisation, molecular size, formulation, and surface area of the absorption site.
93
What is ADME?
Absorption, Distribution, Metabolism, Elimination — the pharmacokinetic journey of a drug through the body.
94
What are the functional groups present in amino acids?
A carboxylic acid group (–COOH), an amino group (–NH2), a hydrogen atom, and a variable side chain (R-group) attached to the alpha carbon.
95
What is the isoelectric point (pI)?
The pH at which an amino acid has no net electrical charge (zwitterion form).
96
Which amino acid is not chiral?
Glycine – it has two hydrogen atoms on the alpha carbon.
97
What type of bond links amino acids in peptides and proteins?
Peptide bonds, which are amide bonds formed through condensation (loss of water).
98
What structural feature gives peptide bonds rigidity?
Resonance hybridisation, leading to partial double-bond character and restricted rotation.
99
What are the four categories of amino acid side chains?
Non-polar, polar uncharged, acidic, and basic.
100
What configuration do naturally occurring amino acids have?
L-configuration; almost all are S under CIP rules except cysteine (R).
101
What defines protein solubility in water?
The surface distribution of polar and charged amino acids (hydrophilic residues).
102
What are zwitterions?
Molecules with both positive and negative charges but an overall neutral charge, typical of amino acids at physiological pH.
103
What is the empirical formula of carbohydrates?
(CH2O)n, meaning hydrated carbon.
104
Differentiate between aldose and ketose.
Aldose has an aldehyde group; ketose has a ketone group.
105
What is the cyclic form of a sugar?
A hemiacetal or hemiketal formed by reaction of a carbonyl group with a hydroxyl group.
106
What is an anomeric carbon?
The carbon derived from the carbonyl carbon during ring formation; can form α or β isomers.
107
What is mutarotation?
Interconversion between α- and β-anomers via the open-chain form in aqueous solution.
108
What is lactose composed of?
β-1,4 linked galactose and glucose; requires lactase for digestion.
109
What is the difference between starch and cellulose?
Starch (amylose/amylopectin) has α-linkages; cellulose has β-1,4 linkages which humans cannot digest.
110
What are glycosides?
Acetals formed when a sugar's anomeric OH reacts with another molecule’s OH/NH/SH.
111
Why are sugars reducing agents?
Due to their free aldehyde or ketone groups (in open-chain form).
112
What are fatty acids?
Long-chain carboxylic acids; monomer units of many lipids.
113
What are saturated vs unsaturated fatty acids?
Saturated have no C=C double bonds; unsaturated have one or more.
114
What are triglycerides?
Lipids made of glycerol esterified with three fatty acids; main energy storage molecules.
115
What are phospholipids?
Lipids with two fatty acids and a phosphate group; major component of cell membranes.
116
What is the function of cholesterol?
Membrane fluidity, precursor of steroid hormones (e.g., oestrogens, androgens).
117
What is amphipathic?
A molecule with both hydrophilic and hydrophobic regions; e.g., phospholipids.
118
What is the function of lipids in pharmaceutics?
They affect drug solubility, membrane permeability, and drug delivery system design.
119
What is an enzyme?
A biological catalyst, usually a protein, that increases the rate of chemical reactions without being consumed.
120
What does the Michaelis-Menten equation describe?
V = Vmax*[S]/(Km + [S]); shows how enzyme velocity depends on substrate concentration.
121
What is Vmax?
The maximum velocity of an enzyme-catalyzed reaction when all active sites are saturated.
122
What is Km?
The substrate concentration at which velocity is half of Vmax; indicates enzyme affinity.
123
What are competitive inhibitors?
Molecules that bind the active site and prevent substrate binding; reversible by increasing substrate.
124
What are non-competitive inhibitors?
Bind away from the active site and reduce Vmax without affecting Km; not overcome by more substrate.
125
What are cofactors and coenzymes?
Non-protein helpers required for enzyme activity. Cofactors are often metals; coenzymes are organic (e.g., vitamins).
126
What are allosteric enzymes?
Enzymes with regulatory and catalytic sites; subject to feedback inhibition and cooperativity.
127
What is feedback inhibition?
A regulatory mechanism where a downstream product inhibits an upstream enzyme in the same pathway.
128
What is metabolism?
The sum of all chemical reactions in the body; includes catabolism (breakdown) and anabolism (synthesis).
129
What is ATP?
Adenosine triphosphate; the main energy currency of the cell.
130
What happens in glycolysis?
Glucose is converted to pyruvate, producing 2 ATP and 2 NADH per glucose.
131
What is the Krebs cycle?
A mitochondrial cycle that produces NADH, FADH2, and CO2 from acetyl-CoA.
132
What is the electron transport chain?
A mitochondrial membrane system that uses NADH/FADH2 to generate ATP by oxidative phosphorylation.
133
What is beta-oxidation?
The breakdown of fatty acids into acetyl-CoA in the mitochondria, producing NADH and FADH2.
134
What is gluconeogenesis?
Synthesis of glucose from non-carbohydrate precursors (e.g., pyruvate, lactate, glycerol).
135
What is the urea cycle?
A liver cycle that converts toxic NH4+ from amino acid breakdown into excretable urea.
136
What enzyme catalyzes the first step of glycolysis?
Hexokinase (or glucokinase in liver); phosphorylates glucose to glucose-6-phosphate.
137
What enzyme is the rate-limiting step of glycolysis?
Phosphofructokinase-1 (PFK-1); converts fructose-6-phosphate to fructose-1,6-bisphosphate.
138
What enzyme converts phosphoenolpyruvate (PEP) to pyruvate?
Pyruvate kinase.
139
What is the net ATP yield of glycolysis per glucose?
2 ATP (4 produced – 2 used) and 2 NADH.
140
What happens to NADH from glycolysis in aerobic conditions?
Each NADH enters mitochondria and yields ~2.5 ATP via oxidative phosphorylation.
141
What enzyme converts pyruvate to acetyl-CoA?
Pyruvate dehydrogenase complex (PDC), a key link between glycolysis and Krebs cycle.
142
What are the 3 rate-limiting enzymes in the Krebs cycle?
Citrate synthase, isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase.
143
How many ATP are generated per turn of the Krebs cycle?
Each turn yields: 3 NADH (7.5 ATP), 1 FADH2 (1.5 ATP), 1 GTP (1 ATP equivalent) → ~10 ATP total.
144
How many total ATP from Krebs cycle per glucose?
Two turns per glucose (2 acetyl-CoA), yielding ~20 ATP.
145
What is the total ATP yield from complete aerobic metabolism of one glucose?
~30–32 ATP: 2 from glycolysis, 2 from Krebs, 25–28 from oxidative phosphorylation.
146
What enzyme initiates beta-oxidation of fatty acids?
Acyl-CoA synthetase (activates fatty acid by adding CoA).
147
How are long-chain fatty acids transported into mitochondria?
Via the carnitine shuttle (CPT-I and CPT-II enzymes).
148
What are the 4 recurring steps of beta-oxidation?
1. Oxidation by FAD (→ FADH2), 2. Hydration, 3. Oxidation by NAD+ (→ NADH), 4. Thiolysis (cleavage to acetyl-CoA).
149
How many ATP does one FADH2 yield?
1.5 ATP via electron transport chain.
150
How many ATP does one NADH yield?
2.5 ATP via electron transport chain.
151
What is the ATP yield from one turn of β-oxidation?
1 FADH2 (1.5 ATP), 1 NADH (2.5 ATP), 1 acetyl-CoA (10 ATP) → Total = 14 ATP per cycle after the first.
152
How many β-oxidation cycles for palmitic acid (C16)?
7 cycles (C16 → 8 acetyl-CoA).
153
How many total ATP from oxidation of palmitic acid (C16)?
8 acetyl-CoA → 80 ATP; 7 FADH2 → 10.5 ATP; 7 NADH → 17.5 ATP; minus 2 ATP for activation → **Total: 106 ATP**.
154
What enzyme converts oxaloacetate to phosphoenolpyruvate in gluconeogenesis?
PEP carboxykinase (PEPCK).
155
What enzyme removes nitrogen in amino acid catabolism?
Transaminase (e.g., alanine aminotransferase) and glutamate dehydrogenase (oxidative deamination).
156
What is the key enzyme of the urea cycle?
Carbamoyl phosphate synthetase I; catalyzes the first step using NH4+ and CO2.
157
What organ carries out gluconeogenesis and the urea cycle?
The liver.
158
Why is ATP production from lipids greater than from carbohydrates?
Fatty acids are more reduced, yielding more NADH/FADH2 per carbon and are not hydrated like glycogen.
159
What is substrate-level phosphorylation?
ATP generation directly from a chemical reaction (e.g., glycolysis or Krebs), not via the electron transport chain.
160
What is oxidative phosphorylation?
ATP generation using the energy from NADH/FADH2 as electrons pass through the electron transport chain.
161
GLYCOLYSIS (Cytosol)
Glucose → 2 Pyruvate
2 ATP used (Steps 1 & 3)
4 ATP produced (Steps 7 & 10)
Net Gain: 2 ATP
2 NADH → ~5 ATP via oxidative phosphorylation
▶ Total: ~7 ATP
162
PYRUVATE DEHYDROGENASE COMPLEX (Mitochondria)
2 Pyruvate → 2 Acetyl-CoA + 2 NADH
▶ ~5 ATP
163
KREBS (TCA) CYCLE (Mitochondrial Matrix)
Per 1 Acetyl-CoA (x2 per glucose):
3 NADH → 7.5 ATP
1 FADH2 → 1.5 ATP
1 GTP → 1 ATP
▶ 10 ATP per cycle × 2 = 20 ATP
164
OXIDATIVE PHOSPHORYLATION
NADH = ~2.5 ATP
FADH2 = ~1.5 ATP
165
TOTAL ATP FROM 1 GLUCOSE (AEROBIC)
Glycolysis: 2 ATP + 2 NADH = 7 ATP
Pyruvate DH: 2 NADH = 5 ATP
TCA Cycle: 6 NADH + 2 FADH2 + 2 GTP = 20 ATP
▶ Grand Total: ~30–32 ATP
166
BETA-OXIDATION (Palmitic Acid, C16:0)
7 FADH2 → 10.5 ATP
7 NADH → 17.5 ATP
8 Acetyl-CoA → 80 ATP via Krebs
Activation cost: −2 ATP
▶ Total = 106 ATP
167
GLUCONEOGENESIS (Liver)
Converts pyruvate/lactate/glycerol → glucose
Requires ~6 ATP per glucose
Key enzymes:
Pyruvate carboxylase
PEPCK
Fructose-1,6-bisphosphatase
Glucose-6-phosphatase
168
UREA CYCLE (Liver)
Detoxifies ammonia (NH₄⁺) → urea
Key enzyme: Carbamoyl phosphate synthetase I
Energy cost: ~3 ATP per urea
169
170
What is the transition state in enzymatic reactions?
The high-energy, unstable state that substrates must pass through; enzymes stabilize it to lower activation energy.
171
What is enzyme specificity based on?
The exact shape and chemistry of the active site, which matches a specific substrate.
172
What is kcat (turnover number)?
The number of substrate molecules converted to product per enzyme per second at full saturation.
173
What is the effect of a competitive inhibitor on Km and Vmax?
Increases Km (decreased affinity), no change to Vmax.
174
What is the effect of a non-competitive inhibitor on Km and Vmax?
No change to Km, but decreases Vmax.
175
What is the role of phospholipids in membranes?
They form a bilayer with hydrophobic tails inward and hydrophilic heads outward, allowing selective permeability.
176
What molecules can diffuse freely through the membrane?
Small nonpolar molecules (e.g., O2, CO2, steroids).
177
What molecules require transport proteins to cross membranes?
Ions, glucose, amino acids – generally polar or large molecules.
178
What are lipid rafts?
Microdomains in the membrane enriched in cholesterol and sphingolipids that compartmentalize signaling.
179
What is the function of the smooth ER?
Lipid synthesis, calcium storage, and detoxification.
180
What does the nuclear envelope consist of?
A double membrane with nuclear pores that regulate exchange between nucleus and cytoplasm.
181
182
What is the G0 phase?
A quiescent state where cells exit the cycle and cease dividing (e.g., neurons).
183
What is the restriction point in G1?
A checkpoint after which the cell is committed to completing the cycle.
184
What is desensitization in signaling?
A process where receptors are inactivated, internalized, or downregulated in response to prolonged stimulation.
185
What are nuclear hormone receptors?
Receptors inside the cell that, when activated, bind DNA and regulate gene transcription (e.g., steroid receptors).
186
What is intrinsic activity?
The ability of a drug to activate a receptor and produce a response (full agonist = 1, antagonist = 0).
187
What is the Hill coefficient?
A measure of cooperativity in ligand binding to receptors (n > 1 = positive cooperativity).
188
What is a functional antagonist?
A drug that produces opposite effects via a different mechanism, not via the same receptor.
189
What are examples of ligand-gated ion channels?"
Nicotinic ACh receptor, GABA-A receptor, NMDA receptor.
190
What is the role of K⁺ channels in neurons?
They help repolarize the membrane after depolarization, restoring resting potential.
191
What is clonal selection?
The process by which only B or T cells with specific receptors for an antigen are activated and cloned.
192
What is the role of MHC I and II?
MHC I presents to CD8⁺ T cells (all nucleated cells); MHC II presents to CD4⁺ T cells (APCs only).
193
What is the role of the hypothalamus in homeostasis?
Acts as the body's control center for temperature, thirst, hunger, and circadian rhythm.
194
What is clonal selection?
The process by which only B or T cells with specific receptors for an antigen are activated and cloned.
195
What is the role of MHC I and II?
MHC I presents to CD8⁺ T cells (all nucleated cells); MHC II presents to CD4⁺ T cells (APCs only).
196
What are enzymes?
Enzymes are biological catalysts, usually proteins, that speed up chemical reactions without being consumed.
197
How do enzymes catalyze reactions?
By lowering the activation energy required for the reaction.
198
What is the active site of an enzyme?
The specific region of the enzyme where the substrate binds and the reaction occurs.
199
What are common enzyme types based on function?
Oxidases, Reductases, Hydrolases, Lyases, Ligases, Isomerases, Transferases.
200
What is a coenzyme?
An organic molecule required for enzyme function, e.g. NAD⁺, FAD, biotin.
201
What is a cofactor?
A non-protein chemical element required for activity, often metal ions like Zn²⁺ or Mg²⁺.
202
What is an allosteric enzyme?
An enzyme with regulatory sites in addition to active sites; responds to effectors.
203
What is feedback inhibition?
A form of enzyme regulation where the end product inhibits an upstream enzyme.
204
Which 5 factors affect enzyme activity?
Temperature, pH, substrate concentration, small molecule binding (cofactors), covalent modification (e.g. phosphorylation).
205
Q
A
206
What is the structure of the cell membrane?
A phospholipid bilayer with embedded proteins, forming a fluid mosaic model.
207
What are the four main functions of the cell membrane?
1. Physical barrier, 2. Selective permeability, 3. Electrochemical gradient maintenance, 4. Communication via receptors.
208
What are amphipathic lipids?
Lipids with both hydrophilic and hydrophobic regions, such as phospholipids and cholesterol.
209
What is membrane potential?
The electrical potential difference across the membrane, critical for muscle and neuron function.
210
211
What is the structure of the cell membrane?
A phospholipid bilayer with embedded proteins, forming a fluid mosaic model.
212
What are the four main functions of the cell membrane?
1. Physical barrier, 2. Selective permeability, 3. Electrochemical gradient maintenance, 4. Communication via receptors.
213
What are amphipathic lipids?
Lipids with both hydrophilic and hydrophobic regions, such as phospholipids and cholesterol.
214
What is membrane potential?
The electrical potential difference across the membrane, critical for muscle and neuron function.
215
What distinguishes eukaryotic cells from prokaryotic?
Eukaryotes have a true nucleus and membrane-bound organelles.
216
What are examples of membrane-bound organelles?
Nucleus, mitochondria, ER, Golgi apparatus, lysosomes.
217
What are the four stages of the cell cycle?
G1 (growth), S (DNA synthesis), G2 (prep), M (mitosis).
218
What regulates the cell cycle?
Cyclins and cyclin-dependent kinases (CDKs).
219
What are the four main receptor types?
1. Ion channel, 2. G-protein coupled, 3. Enzyme-linked, 4. Nuclear receptors.
220
What is affinity?
How strongly a drug binds to its receptor.
221
What is efficacy?
The ability of a bound drug to produce a response.
222
What is an agonist?
A molecule that binds and activates a receptor.
223
What is an antagonist?
A molecule that binds but does not activate the receptor; blocks agonists.
224
What is signal transduction?
The process by which a cell responds to external signals via receptors and intracellular pathways.
225
What types of cell signalling exist?
Autocrine, paracrine, endocrine, juxtacrine.
226
What are examples of second messengers?
cAMP, Ca²⁺, IP₃, DAG.
227
What is a competitive antagonist?
Binds the same site as the agonist; reversible by increasing agonist concentration.
228
What is a non-competitive antagonist?
Binds elsewhere or irreversibly and cannot be overcome by increasing agonist.
229
What is physiological antagonism?
Two drugs with opposing effects via different pathways (e.g., adrenaline vs histamine).
230
What are ion channels?
Pore-forming proteins that allow ions to pass through membranes.
231
What are voltage-gated channels?
Channels that open/close in response to membrane potential changes.
232
What are ligand-gated channels?
Channels that open in response to binding of a chemical ligand.
233
What ions are key in action potentials?
Na⁺, K⁺, Ca²⁺, Cl⁻.
234
What is homeostasis?
The body's ability to maintain a stable internal environment despite external changes.
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Which systems maintain homeostasis?
Nervous, endocrine, respiratory, renal, cardiovascular systems.
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Q
A
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What are the two types of immunity?
Innate (non-specific) and adaptive (specific with memory).
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What are examples of innate immune cells?
Neutrophils, eosinophils, basophils, mast cells, macrophages, dendritic cells, NK cells.
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What are the roles of B cells?
Produce antibodies (humoral immunity).
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What are the roles of T cells?
Helper T cells coordinate responses; cytotoxic T cells kill infected cells.
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What are antigen-presenting cells (APCs)?
Cells like dendritic cells and macrophages that display antigens to T cells.
