Topics for Biological Science Section of the MCAT

Topics for Biological Science Section of the MCAT
Topics for Biological Science Section of the MCAT

source: http://www.aamc.org/students/mcat/preparing/bstopics.pdf

Biology
Molecular Biology: Enzymes and Metabolism
A. ENZYME STRUCTURE AND FUNCTION
1. Function of enzymes in catalyzing biological reactions
2. Reduction of activation energy
3. Substrates an enzyme specificity
B. CONTROL OF ENZYME ACTIVITY
1. Feedback inhibition
2. Competitive inhibition
3. Non-competitive inhibition
C. BASIC METABOLISM
1. Glycolysis, anaerobic and aerobic, substrates and products
2. Krebs cycle, substrates and products, general features of the pathway
3. Electron transport chain and oxidative phosphorylation, substrates and products,
general features of the pathway
4. Metabolism of fats and proteins
Molecular Biology: DNA and Protein Synthesis
I. DNA STRUCTURE AND FUNCTION
A. DNA STRUCTURE AND FUNCTION
1. Watson-Crick model of DNA; double helix
2. DNA composition: purine and pyrimidine bases, sugars, phosphate
3. Base pairing specificity: A with T, G with C
4. Function in transmission of genetic information
B. DNA REPLICATION
1. Mechanism of replication: separation of strands, specific coupling of free
nucleic acids
2. Semi-conservative nature of replication
C. REPAIR OF DNA
1. Repair during replication
2. Repair of mutations
D. RECOMBINANT DNA
1. Restriction enzymes
2. Hybridization
3. Gene cloning
II. PROTEIN SYNTHESIS
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Topics for Biological Science Section of the MCAT
A. GENETIC CODE
1. Central Dogma: DNA → RNA → protein
2. Codon-anticodon relationship
3. Missense, nonsense codons
4. Initiation, termination codons
B. TRANSCRIPTION
1. Messenger RNA
2. tRNA, rRNA
3. Mechanism of transcription
C. TRANSLATION
1. Roles of mRNA, tRNA, rRNA
2. Role and structure of ribosomes
Molecular Biology: Eukaryotes
A. EUKARYOTIC CHROMOSOME ORGANIZATION
1. Chromosomal proteins
2. Telomeres, centromeres
B. CONTROL OF GENE EXPRESSION IN EUKARYOTES
1. Transcription regulation
2. DNA binding proteins, transcription factors
3. Cancer as a failure of normal cellular controls, oncogenes
4. Post-transcriptional control [GEC]
Genetics
A. MENDELIAN CONCEPTS
1. Phenotype and genotype
2. Gene
3. Locus
4. Allele: single and multiple
5. Homo- and heterozygosity
6. Wild type
7. Recessiveness
8. Complete dominance
9. Co-dominance
10. Incomplete dominance, leakage, penetrance, expressivity
11. Gene pool
B. MEIOSIS AND GENETIC VARIABILITY
1. Significance of meiosis
2. Important differences between meiosis and mitosis
3. Segregation of genes
a. Independent assortment
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Topics for Biological Science Section of the MCAT
b. linkage
c. recombination
d. single crossovers
e. double crossovers
4. Sex-linked characteristics
a. very few genes on Y chromosome
b. sex determination
c. cytoplasmic inheritance
5. Mutation
a. general concept of mutation-error in DNA sequence
b. types of mutations: random, translation error, transcription error,
base substitution, inversion, addition, deletion, translocation,
mispairing
c. advantageous vs. deleterious mutation
d. inborn errors of metabolism
e. relationship of mutagens to carcinogens
C. ANALYTIC METHODS
1. Hardy-Weinberg Principle
2. Test cross: back cross, concepts of parental, F1 and F2 generations
Microbiology
A. FUNGI
1. General characteristics
2. General aspects of life cycle
B. VIRUS STRUCTURE
1. General structural characteristics, nucleic acid and protein
2. Lack organelles, nucleus
3. Structural aspects of typical bacteriophage
4. Genomic content RNA or DNA
5. Size relative to bacteria and eukaryotic cells
C. VIRAL LIFE CYCLE
1. Self-replicating biological units that must reproduce within specific host cell
2. Generalized phage and animal virus life cycles:
a. attachment to host, penetration of cell membrane or cell wall, and
entry of viral genetic material
b. use of host synthetic mechanism to replicate viral components
c. self-assembly and release of new viral particles
3. Retrovirus life cycle: integration into host DNA
4. Transduction: transfer of genetic material by viruses [MIC]
D. PROKARYOTIC CELL: STRUCTURE, BACTERIA
1. Lack of nuclear membrane, mitotic apparatus
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Topics for Biological Science Section of the MCAT
2. Lack of typical eukaryotic organelles
3. Major classifications of bacteria by shape: bacilli (rod-shaped); spirilli (spiral
shaped); cocci (spherical); eubacteria; archaea
4. Presence of cell wall in bacteria
5. Flagellar propulsion, mechanism
E. PROKARYOTIC CELL: GROWTH AND PHYSIOLOGY
1. Reproduction by fission
2. High degree of genetic adaptability, acquisition of antibiotic resistance
3. Exponential growth
4. Existence of anaerobic and aerobic variants
5. Parasitic and symbiotic
F. PROKARYOTIC CELL: GENETICS
1. Existence of plasmids, extragenomic DNA
2. Transformation: incorporation into bacterial genome of DNA fragments from
external medium
Generalized Eukaryotic Cell
A. NUCLEUS
1. Defining characteristics: membrane bound nucleus, presence of organelles,
meiotic division
2. Nucleus: compartmentalization, storage of genetic information
3. Nucleolus: location and function
4. Nuclear envelope, nuclear pores
B. MEMBRANE-BOUNE ORGANELLES
1. Mitochondria
a. site of ATP production
b. self-replication
c. inner and outer membrane
2. Lysosomes: membrane vesicle containing hydrolytic enzymes
3. Endoplasmic reticulum:
a. rough and smooth components
b. rough endoplasmic reticulum site of ribosomes
c. double membrane structure, role in membrane biosynthesis
d. role in biosynthesis of secreted proteins
4. Golgi apparatus: general structure and role in packaging and secretion
C. PLASMA MEMBRANE
1. General function in cell containment
2. Protein and lipid components, fluid mosaic model
3. Osmosis
4. Passive and active transport
5. Membrane channels
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6. Sodium/potassium pump
7. Membrane receptors
8. Membrane potential
9. Exocytosis and endocytosis
10. Cell-cell communication (General concepts of cellular adhesion)
a. gap junctions
b. tight junctions
c. desmosomes
D. CYTOSKELETON
1. General function in cell support and movement
2. Microfilaments: composition and role in cleavage and contractility
3. Microtubules: composition and role in support and transport
4. Intermediate filaments, role in support
5. Composition and function of eukaryotic cilia and flagella
6. Centrioles, microtubule organizing centers
E. MITOSIS
1. Mitotic process: prophase, metaphase, anaphase, telophase, interphase
2. Mitotic structures:
a. centrioles, asters, spindles
b. chromatids, centromeres, kinetochores
c. nuclear membrane breakdown and reorganization
d. mechanisms of chromosome movement
3. Phases of cell cycle: G0, G1, S, G2, M
4. Growth arrest
Specialized Eukaryotic Cells and Tissues
A. NERVE CELL/NEURAL
1. Cell body: site of nucleus, organelles
2. Axon: structure and function
3. Dendrites: branched extensions of cell body
4. Myelin sheath, Schwann cells, insulation of axon
5. Nodes of Ranvier: propagation of nerve impulse along axon
6. Synapse: site of impulse propagation between cells
7. Synaptic activity
a. transmitter molecules
b. synaptic knobs
c. fatigue
d. propagation between cells without resistance loss
8. Resting potential: electrochemical gradient
9. Action potential
a. threshold, all-or-none
b. sodium/potassium pump
10. Excitatory and inhibitory nerve fibers: summation, frequency of firing
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Topics for Biological Science Section of the MCAT
B. MUSCLE CELL/CONTRACTILE
1. Structural characteristics of striated, smooth, and cardiac muscle
2. Abundant mitochondria in red muscle cells-ATP source
3. Organization of contractile elements: actin and myosin filaments, crossbridges,
sliding filament model
4. Calcium regulation of contraction
5. Sacromeres: “I” and “A” bands, “M” and “Z” lines, “H” zone (General structure
only)
6. Presence of troponin and tropomyosin
7. Calcium regulation of contraction
C. OTHER SPECIALIZED CELL TYPES
1. Epithelial cells (cell types, simple epithelium, stratified epithelium)
2. Endothelial cells
3. Connective tissue cells (major cell types, fiber types, loose vs. dense, cartilage,
extracellular matrix)
Nervous and Endocrine Systems
A. ENDOCRINE SYSTEM: HORMONES
1. Function of endocrine system: specific chemical control at cell, tissue, and organ
level
2. Definition of endocrine gland, hormone
3. Major endocrine glands: names, locations, products
4. Major types of hormones
B. ENDOCRINE SYSTEM: MECHANISMS OF HORMONE ACTION
1. Cellular mechanisms of hormone action
2. Transport of hormones: blood supply
3. Specificity of hormones: target tissue
4. Integration with nervous system: feedback control
C. NERVOUS SYSTEM: STRUCTURE AND FUNCTION
1. Major functions
a. high level control and integration of body systems
b. adaptive capability to external influences
c. sensory input
d. integrative and cognitive ability
2. Organization of vertebrate nervous system
3. Sensor and effector neurons
4. Sympathetic and parasympathetic nervous systems: antagonistic control
5. Reflexes
a. feedback loop, reflex arc
b. role of spinal cord, brain
c. efferent control
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Topics for Biological Science Section of the MCAT
D. NERVOUS SYSTEM: SENSORY RECEPTION AND PROCESSING
1. Skin, proprioceptive, and somatic sensors
2. Olfaction, taste
3. Hearing
a. ear structure
b. mechanism of hearing
4. Vision
a. light receptors
b. eye structure
c. visual image processing
Circulatory, Lymphatic, and Immune Systems
A. CIRCULATORY SYSTEM
1. Functions: circulation of oxygen, nutrients, hormones, ions and fluids, removal of
metabolic waste
2. Role in thermoregulation
3. Four-chambered heart: structure and function
4. Systolic and diastolic pressure
5. Pulmonary and systemic circulation
6. Arterial and venous systems
a. structural and functional differences
b. pressure and flow characteristics
7. Capillary beds
a. mechanisms of gas and solute exchange
b. mechanism of heat exchange
c. source of peripheral resistance
8. Composition of blood
a. plasma, chemicals, blood cells
b. erythrocyte production and destruction; spleen, bone marrow
c. regulation of plasma volume
d. coagulation, clotting mechanisms
9. Oxygen transport by blood
a. hemoglobin, hematocrit
b. oxygen content
c. oxygen affinity
10. Details of oxygen transport (biochemical characteristics of hemoglobin)
a. modification of oxygen affinity
B. LYMPHATIC SYSTEM
Major functions
a. equalization of fluid distribution
b. transport of proteins and large glycerides
c. production of lymphocytes involved in immune reactions
d. return of materials to the blood
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Topics for Biological Science Section of the MCAT
e. Composition of lymph: similarity to blood plasma; substances
transported
f. Source of lymph: diffusion from capillaries by differential pressure
g. Lymph nodes: activation of lymphocytes
C. IMMUNE SYSTEM
1. Cells
a. T-lymphocytes
b. B-lymphocytes
2. Tissues
a. bone marrow
b. spleen
c. thymus
d. lymph nodes
3. Concept of antigen and antibody
4. Structure of antibody molecule
5. Mechanism of stimulation by antigen
Respiratory System
A. RESPIRATORY SYSTEM
1. General function
a. gas exchange, thermoregulation
b. protection against disease, particulate matter
2. Breathing mechanisms
a. diaphragm, rib cage, differential pressure
b. resiliency and surface tension effects
Skin System
A. SKIN SYSTEM
1. Functions in homeostasis and osmoregulation
2. Functions in thermoregulation
a. hair, erectile musculature
b. fat layer for insulation
c. sweat glands, location in dermis
d. vasoconstriction and vasodilation in surface capillaries
3. Physical Protection
a. nails, calluses, hair
b. protection against abrasion, disease organisms
4. Structure (detail structure)
a. layer differentiation
b. relative impermeability to water
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Topics for Biological Science Section of the MCAT
Digestive and Excretory Systems
A. DIGESTIVE SYSTEM
1. Ingestion
a. saliva as lubrication and source of enzymes
b. epiglottal action
c. esophagus, transport function
2. Stomach
a. storage and churning of food
b. low pH, gastric juice, mucal protection against self-destruction
c. production of digestive enzymes, site of digestion
d. structure
3. Liver
a. production of bile
b. role in nutrient metabolism, vitamin storage
c. role in blood glucose regulation, detoxification
4. Bile
a. storage in gall bladder
b. function
5. Pancreas
a. production of enzymes
b. transport of enzymes to small intestine
c. structure (gross)
6. Small Intestine
a. absorption of food molecules
b. Function of structure of villi
c. Production of enzymes, site of digestion
d. Neutralization of stomach acid
e. Structure (gross)
7. Large Intestine
a. anatomic subdivisions
b. absorption of water
c. bacterial flora
d. structure (gross)
8. Rectum: storage and elimination of waste, feces
9. Muscular control
a. sphincter muscle
b. peristalsis
B. EXCRETORY SYSTEM
1. Roles in homeostasis
a. blood pressure
b. osmoregulation
c. acid-base balance
d. removal of soluble nitrogenous
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Topics for Biological Science Section of the MCAT
2. Kidney structure
a. Cortex
b. medulla
3. Nephron structure
a. Glomerulus
b. Bowman’s capsule
c. Proximal tubule
d. Loop of Henle
e. Distal tubule
f. Collecting duct
4. Formation of urine
a. glomerular filtration
b. secretion and reabsorption of solutes
c. concentration of urine
d. counter-current multiplier mechanism
5. Storage and elimination: ureter, bladder, urethra
Muscle and Skeletal Systems
A. MUSCLE SYSTEM
1. Important functions
a support, mobility
b peripheral circulatory assistance
c thermoregulation (shivering reflex)
2. Structure of three basic muscle types: striated, smooth, cardiac
3. Nervous control
a motor neurons
b neuromuscular junctions, motor end plates
c voluntary and involuntary muscles
d sympathetic and parasympathetic innervation
E. SKELETAL SYSTEM
1. Functions
a structural rigidity and support
b calcium storage
c physical protection
2. Skeletal structure
a specialization of bone types, structures
b joint structures
c endo-vs. exoskeleton
3. Cartilage: structure and function
4. Ligaments, tendons
5. Bone structure
a calcium/protein matrix
b bone growth
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Topics for Biological Science Section of the MCAT
Reproductive System and Development
A. REPRODUCTIVE
1. Male and female reproductive structures and their functions
a. gonads
b. genitalia
c. differences between male and female structures
2. Gametogenesis by meiosis
3. Ovum and sperm
a. differences in formation
b. differences in morphology
c. relative contribution to next generation
4. Reproductive sequence: fertilization; implantation; development; birth
B. EMBRYOGENESIS
1. Stages of early development: order and general features of each
a. Fertilization
b. Cleavage
c. blastula formation
d. gastrulation
i. first cell movements
ii. formation of primary germlayers: endoderm, mesoderm, ectoderm
e. neurulation
2. Major structures arising out of primary germ layers
E. DEVELOPMENTAL MECHANISMS
1. Cell specialization
a determination
b differentiation
c tissue types
2. Cell communication in development
3. Gene regulation in development
4. Programmed cell death
Evolution
A. EVOLUTION
1. Natural selection
a. fitness concept
b. selection by differential reproduction
c. concepts of natural and group selection
d. evolutionary success as increase in percent representation in the gene
pool of the next generation
2. Speciation
a. Definition of species
b. Polymorphism
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c. Adaptation and specialization
d. Concepts of ecological nice, competition
e. Concept of population growth through competition
f. Inbreeding
g. Out breeding
h. Bottlenecks
i. Divergent, parallel, and convergent evolution
j. Symbiotic relationships
i. Parasitism
ii. Commensalism
3. Ontogeny recapitulates phylogeny
4. Evolutionary time as measured by gradual random changes in genome
5. Origin of life
B. COMPARATIVE ANATOMY
1. Chordate features
a. Notochord
b. Pharangeal pouches, brachial arches
c. Dorsal nerve cord
2. Vertebrate phylogeny: vertebrate classes and relations to each other
Organic Chemistry
The Covalent Bond
1. σ and π bonds (No Alkenes)
a. hybrid orbitals: sp³, sp², sp and respective geometries
b. valence shell electrons pair repulsion and the prediction of shapes of molecules
(e.g., NH3, H2O, CO2)
c. structural formulas for molecules involving H, C, N, O, F, S, P, Si, C1
d. delocalized electrons and resonance in ions and molecules
2. Multiple bonding (No Alkenes)
a. Its effect on bond length and bond energies
b. Rigidity in molecular structure
3. Stereochemsitry of covalently bonded molecules
a. Isomers
i. Structural isomers
ii. Stereoisomers (e.g. diastereomers, enantiomers, cis/trans isomers)
iii. Conformational isomers
b. Polarization of light, specific rotation
c. Absolute and relative configuration
i. Conventions for writing R and S forms
ii. Conventions for writing E and Z forms
d. racemic mixtures, separation of enantiomers by biological means
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Topics for Biological Science Section of the MCAT
Molecular Structure and Spectra
1. Absorption spectroscopy
a. infrared region
i. intramolecular vibrations and rotations
ii. recognizing common characteristic group absorptions, fingerpoint region
b. visible region
i. absorption in visible region gives complementary color (e.g., carotene)
ii. effect of structural changes on absorption (e.g., indicators)
c. ultraviolet region (No Alkenes)
i. Л-electron and non-bonding electron transition
ii. Conjugated systems
2. Mass spectroscopy: m/e ratio, parent peak
3. NMR spectroscopy
a. protons in a magnetic field; equivalent protons
b. spin-spin splitting
Separations and Purifications
1. Extraction: distribution of solute between two immiscible solvents
2. Distillation
3. Chromatography-basic principles involved in separation process
a. column chromatography
i. gas-liquid chromatography
b. paper chromatography
4. Recrystalization; solvent choice from solubility data
Hydrocarbons
ALIPHATIC – ALKANES
1. Description
a. nomenclature
b. physical properties
2. Important reactions
a. combustion
b. Substitution reactions with halogens, etc.
3. General principles
a. stability of free radicals; chain reaction mechanism; inhibition
b. ring strain in cyclic compounds
c. bicycle molecules
Oxygen Containing Compounds
A. ALCOHOLS
1. Description
a. nomenclature
b. physical properties
c. infrared absorption of OH group
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Topics for Biological Science Section of the MCAT
2. Important reactions
a. substitution reactions: SN1 or SN2, depending on alcohol and derived alkyl
halide
b. oxidation
c. pinacol rearrangement in polyhydroxyalcohols; synthetic uses
d. protection of alcohols
e. reactions with SOCl2 and PBr3
f. preparation of mesylates and tosylates
g. esterification
h. inorganic esters
3. General principles
a. hydrogen bonding
b. acidity of alcohols compared to other classes of oxygen-containing compounds
c. effect of chain branching on physical properties
B. ALDEHYDES AND KETONES
1. Description
a. Nomenclature
b. physical properties
c. infrared absorption of C=O bond
2. Important reactions
a. nucleophilic addition reactions at C=O bond
i. acetal, hemiacetal
ii. imine, enamine
b. reactions at adjacent positions
i. haloform reactions
ii. aldol condensation
iii. oxidation
c. 1, 3-dicarbonyls: internal H-bonding
d. Keto-enol tautomerism
e. Organometallic reagants
f. Acetoacetic ester syntheses
g. Wolff-Kishner reaction
h. Grignard reagants
3. General principles
a. effect of substituents on reactivity of C=O; steric hindrance
b. acidity of α, β-unsaturated carbonyls—resonance structures
C. CARBOXYLIC ACIDS
1. Description
a. nomenclature
b. physical properties and solubility
c. infrared absorption
2. Important reactions
a. carboxyl group reactions
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b. nucleophilic attack
i. reduction
ii. decarboxylation
iii. esterification
c. reactions at 2 position
i. halogenation
ii. substitution reactions
3. General principles
a. H bonding
b. Dimerization
c. acidity of the carboxyl group
d. inductive effect of substituent’s
e. resonance stability of carboxylate anion
D. ACID DERIVATIVES (ACID CHLORIDES, ANHYDRIDES, AMIDES, ESTERS)
1. Description
a. nomenclature
b. physical properties
c. infrared absorption
2. Important Reactions
a. preparation of acid derivatives
b. necleophilic substitution
c. Hoffman degradation of amides; migration of aryl group
d. transesterification
e. hydrolysis of fats and glycerides (saponification)
f. hydrolysis of amides
3. General Principles
a. relative reactivity of acid derivatives
b. steric effects
c. electronic effects
d. strain (e.g. β-lactams)
E. KETO ACIDS AND ESTERS
1. Descriptions; nomenclature
2. Important reactions
a Decarboxylation
b Acetoacetic ester synthesis
3. General principles
a Acidity of α hydrogen and β-keto esters
b Keto-enol tautomerism
Amines
1. Description
a. Nomenclature
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Topics for Biological Science Section of the MCAT
b. Stereochemistry and physical properties
c. Infrared absorption
2. Major reactions
a. Amide formation
b. racions with nitrous acid
c. alkylation
d. Hoffman elimination
3. General principles
a. Basicity
b. stabilization of adjacent carbonium ions (carbocations)
c. effect of substituent on basicity of aromatic amines
Biological Molecules
A. CARBOHYDRATE
1. Description
a. nomenclature and classification, common names
b. absolute configuration
c. cyclic structure and conformations of hexoses
d. epimers and anomers
e. Hydrolysis of the glycoside linkage
B. AMINO ACIDS AND PROTEINS
1. Description
a. absolute configuration at the α position
b. amino acids as dipolar ions classification
c. classification
i. acidic or basic
ii. hydrophobic or hydrophilic
2. Reactions
a peptide linkage
b hydrolysis
3. General principles
a 1° structure of proteins
b 2° structure of proteins
C. LIPIDS
Descriptions; structure
a. steriods
b. terpenes
c. triacyl glycerols
d. free fatty acids
D. PHOSPHORUS COMPOUNDS
1. Description
a. structure of phosphoric acids (anhydrides and esters)
2. Important reactions
a. Wittig reaction
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Topics for Biological Science Section of the MCAT
General Concepts in Organic Chemistry
A. CLASSIFICATION OF ORGANIC COMOUNDS ACCORDING TO
FUNCTIONAL GROUPS
B. REACTIONS, REACTION MECHANISMS, AND THE PRINCIPLES INVOLVED
(metabolic enzyme-controlled reactions and pathways are not included in this
topic area)
C. STRUCTURE AND STEREOCHEMISTRY OF ORGANIC COMPOUNDS
D. IUPAC NOMENCLATURE OF ORGANIC COMPOUNDS
E. MULTISTEP SYNTHESIS/ RETROSYNTHESIS

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