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MCAT Biology

aly chris English 187 cards

Amino acids as dipolar ions pka of NH3 pka of COOH

Cards in this deck (187)

  1. 1Amino acids as dipolar ions pka of NH3 pka of COOHAA as dipolar ions= zwitter ion
    NH3 pka= 9, COOH pka=2    Amino acids as dipolar ions pka of NH3 pka of COOH
  2. 2Amino Acids: Absolute configuration at the α positionabs. config. at alpha position: I think it is just the alpha carbon is the central carbon and everything else is around itAmino Acids: Absolute configuration at the α position
  3. 3Amino acids (non-polar= hydrophobic, polar = hydrophilic), acidic, basicAmino acids (non-polar= hydrophobic, polar = hydrophilic), acidic, basic
  4. 4Amino acid Classifications - Acidic or basic - Hydrophobic or hydrophilicGenerally, if side chain has carboxylic acids, it is acidic and If it has amines, its basic
    - all acid/basic groups are also polar    Amino acid Classifications - Acidic or basic - Hydrophobic or hydrophilic
  5. 5AA Reactions: - Sulfur linkage for ______ - Peptide linkage: polypeptides/ proteins HydrolysisSULFER LINKAGE FOR CYSTEINE/ CYSTINE
    AA Link together by peptide bond
    Peptide bond creates functional group called amide (amine connected to carbonyl carbon)
    hydrolysis breaks bonds    AA Reactions: - Sulfur linkage for ______ - Peptide linkage: polypeptides/ proteins Hydrolysis
  6. 61° structure of proteins 2° structure of proteins 3° structure of proteins; role of proline, cystine, hydrophobic bonding 4° structure of proteins (BIO, BC)• Primary structure: AAs;
    • Secondary structure: alpha helix or beta pleated sheets. Made via Hydrogen bond;
    • Tertiary structure: 3D structure;
    ○ 6 factors that contribute to tertiary structure:
    § Covalent disulfide bonds btwn two cysteine AA
    § Electrostatic/ ionic interactions btwn acidic and basic side chains
    § Hydrogen bonds (N-H - - double bond)
    § Van der Waals forces
    § Hydrophobic bonding: Hydrophobic side chains pushed away from water and toward center of protein
    § R group of proline causes kinks -> no Hydrogen bond can form cuz proline is so big
    □ Proline also causes turns in secondary structure ;
    • Quaternary structure: 2+ polypeptides ;
  7. 7Conformational stability: Denaturing and folding Hydrophobic interactions Solvation layer (entropy) (BC)When native confirmation disrupted = denatured. Loses 2, 3, and 4 structure
    Surrounding molecules form a SOLVATION LAYER that force hydrophobic groups toward center (via ENTROPY!). where a solvent arranges to form an organized layer around something ex. when water molec organize around an ion
  8. 8Non-Enzymatic Protein Function (BIO, BC) binding immune system motors (enzymes end in ___)note, enzymes end in -ase
    BINDING (BC)- receptors or ion channels
    IMMUNE SYSTEM-antibodies
    MOTORS- motor proteins ex. MT
  9. 9Enzyme classification by reaction type Oxideoreductases Transferases hydrolases lyases isomericases ligasesOXIDEOREDUCTASESs: catalyze transfer of e or H+ ions (oxidation reduction rxns);
    TRANSFERASEs- groups transferred on rxn to other (catalyzes this) i.e. A +BX -> AX + B;
    Hydrolases: regulate hydrolysis reactions;
    LYSASES: catalyze reaction where function groups added to double bonds or form double bounds by removing group ;
    ISOMERICASES: catalyze transfer of groups within molecule , produces isomers;
    LIGASES: catalyze condensation rxns couples with hydrolysis of high energy molecules ;
  10. 10Substrates and enzyme specificity Active Site Model Induced-fit Model (what are enzymes made of)Enzymes:
    - Mostly Globular proteins, some are nucleic acids
    Enzyme specificity: only works on one or a few substrates. Enzyme-substrate specificity derives from structural interactions.
    Some enzymes explained by Lock and key model (lock fits certain key only) while others explained by induced fit model (substrate and enzyme shape altered on binding)
  11. 11Mechanism of catalysis: Cofactors Coenzymes Water-soluble vitaminsCoenzyme: organic (carbon based) carrier molecule (holds onto things to make catalysis run smoothly) ex. NADH "carries" e-, or a
    cetyl-coa carries acyl or acetyl groups
    Cofactors: directly involved in catalysis enzyme is doing (doesn’t strictly carry something) but stabilizes enzyme or substrate or help the rxn convert substrates from one form to the other. Ex. Dna polymerase ;
    VITAMINS and minerals: often refers to dietary cofactors and coenzymes ;
  12. 12Enzyme Kinetics: General (catalysis)Enzyme can be protein or RNA!
    Enzymes decrease the activation energy (Ea) of a reaction by lowering the energy of the transition state.
    Enzymes increase the rate of a reaction by decreasing the activation energy.
    Enzymes will increase the rate constant, k, for the equation rate = k[A][B].
    Enzymes do NOT change the Keq of a reaction.
    Enzymes do not change Keq because it lowers the activation energy for BOTH forward and reverse reactions.
    Enzymes will make the reverse reaction go faster also.
    Enzymes do not change ΔG, the net change in free energy.
    Enzymes affect the kinetics of a reaction, but not the thermodynamics
  13. 13Enzyme kinetics: Michaelis–MentenKm is micheales (menten) constant = concentration of substrate at half VmaxEnzyme kinetics: Michaelis–Menten
  14. 14Enzyme (Feedback) regulation: Regulatory enzymes: Allosteric enzymes Covalently-modified enzymes Zymogenfeedback inhibition= the product of a pathway inhibits the pathway
    how enzymes are regulated summary: reversible covalent modification, proteolytic cleavage (i.e. break some bonds to activate it), control proteins, allosteric interactions (modify enzyme configuration by binding activator/inhibitor at specific binding site)
    enzyme released first as inactive form = zymogen
    more details...Enzyme regulation via:
    1. Proteolytic cleavage (irreversible covalent modification)= enzyme released first as inactive form = zymogen . Then special bonds are broken and it become irreversibly active.
    2. Reversible covalent modification - aka add phosphate or something else
    3. Control proteins - protein subunits that inhibit or active enzyme
    Allosteric interactions= allosteric regulation is the modification of an enzyme's configuration through binding of an activator or inhibitor at a specific binding site on the enzyme
  15. 15Inhibition types: Competitive Non-competitive Mixed (BC) Uncompetitive (BC)Irreversible inhibitors- any of the bellow can be irreversible if covalent modification occurs …
    Competitive inhibitors: bind reversibly at active site;
    Uncompetitive inhibitors: bind at site other than active site;
    Mixed inhibitors: bind at site other than active site AND can bind to either just enzyme or enzyme-substrate complex (most hv preference for one or other -> diff effect on Km, if it mostly binds to enzyme like competitive inhibitors than u get increase Km for ex.). Conformational change. ;
    Noncompetitive inhibitor: type of mixed inhibitor, but unlike other mixed inhibitors cant be overcome by excess substrate and don’t change enzyme substrate affinity
  16. 16Inhibition –characteristics (binding site, effect on Km and Kmax): Competitive Non-competitive Mixed (BC) Uncompetitive (BC)Inhibition –characteristics (binding site, effect on Km and Kmax): Competitive Non-competitive Mixed (BC) Uncompetitive (BC)
  17. 17Enzyme inhibition graphs: 1/Km = ____. Vmax = ________-1/Km correlates with enzyme substrate fit. Vmax is max rate of catalysisEnzyme inhibition graphs: 1/Km = ____. Vmax = ________-Enzyme inhibition graphs: 1/Km = ____. Vmax = ________-
  18. 18MineralsMinerals: dissolved inorganic ions inside and outside the cell
    - Assist in transport of stuff going in and out of cell
    Act as cofactors with enzyme ;
  19. 19Nucleic Acid Structure and Function (BIO, BC) Description Nucleotides and nucleosidesAll composed of 3 parts: 5-C (pentose) sugar, Nitrogenous base, Phosphate group
    Nucleoside: pentose sugar + nitrogenous base (same except without P)    Nucleic Acid Structure and Function (BIO, BC) Description Nucleotides and nucleosides
  20. 20NA Pyrimidine, purine residues Base pairing specificity: A with T, G with Cbase is either:
    pyrimidine: C, U, T
    Purine: A, G    NA Pyrimidine, purine residues Base pairing specificity: A with T, G with C
  21. 21NA Sugar phosphate backbonePhosphodiester bond formed between the 3'C on 5-C sugar and phosphate group = SUGAR PHOSPHATE BACKBONE
    Nitrogenous base forms hydrogen bonds with each other in double stranded DNA
  22. 22Deoxyribonucleic acid (DNA): double helix, Watson–Crick model of DNA structure○ Four bases adenine, guanine, cytosine, thymine
    ○ Purines: A G
    ○ Pyrimidines: C T
    ○ Bonds: A=T G-triple bond-C
    ○ Written 5 prime to 3 prime
    ○ Base pairing= hydrogen bonding btwn nitrogenous bases
    § Length of dna is measured in base pairs
  23. 23DNA vs RNA• RNA:
    Ribose instead of deoxyribose as sugar. unlike DNA,RNA can move thru nuclear pores and can b in places besides the nucleus;    DNA vs RNA
  24. 24DNA denaturation, reannealing, hybridizationReannealing or correctly annealing, is the process by which two single strands of DNA combine to form double-stranded DNA.
    hybridization is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules anneal to complementary DNA or RNA.[1]
  25. 25DNA Replication (BIO) Mechanism of replication: separation of strands, specific coupling of free nucleic acids Semi-conservative nature of replication Specific enzymes involved in replication Origins of replication, multiple origins in eukaryotes Replicating the ends of DNA moleculesDNA replication:
    - DNA replication takes place during the S phase of the interphase portion of cell cycle (this allows 2 copies to be present for M phase)
    - Prokaryotes -Replication occurs in middle of chromosome at site called origin of replication . Is bidirectional.
    - MULTIPLE ORIGINS OF REPLICATION IN EURKARYOTES
    - Replisome includes: DNA helicase (unzips double helix), DNA polymerase (adds nucleotides to existing DNA strand started by RNA primer), RNA primer (creates initial part of DNA)
    - DNA polymerase reads parental strand in 3 prime to 5 prime direction (only in this direction), making new strand in 5 prime to 3 prime direction (how DNA strands are normally written)
    § The lagging strand is looped around the replisome giving it the same orientation as the leading strand ;
  26. 26Repair of DNA (BIO): Repair during replication Repair of mutationsDNA polymerase III makes new dna and has ability to proofread (can realize put in wrong base, go back and remove wrong base and put correct base in instead) aka exonuclease activity (because gets rid of last nuclease).
    DNA polymerase 1 removes the rna primer and also has exonuclease activity.
    or proteins can go back in, find a wrong match and mark it with a cut (endonuclease activity). (then dna polymerase adds new base and dna ligase connects bases). = nucleotide excision repair
  27. 27Genetic Code (BIO): Central Dogma mRNA The triplet code Codon–anticodon relationship Degenerate code, wobble pairingCentral Dogma: DNA → RNA → protein
    mRNA is converted to protein
    Triplet code: three nucleotides code for each AA
    3 nucleotide on strand of mRNA : codon;
    Anticodon= will bind to complementary codon on mRNA
    Genetic code = DEGENERATIVE: more than 1 series of three nucleotides can code for same AA;
    Single codon only codes for one AA
    4 nucleotides can be placed in each of 3 positions: 64 times (43);
  28. 28Missense, nonsense codons Initiation, termination codons- Missense mutation: base substitution changes codon -> different amino acid
    -Nonsense mutation: mutation creates stop codon
    Start codon: AUG;
    Stop codons: UAA, UAG, UGA ;
  29. 29Transcription (BIO): Transfer RNA (tRNA); ribosomal RNA (rRNA) Mechanism of transcription mRNA processing in eukaryotes, introns, exons Ribozymes, spliceosomes, small nuclear ribonucleoproteins (snRNPs), small nuclear RNAs (snRNAs) Functional and evolutionary importance of intronsInsert (have)
  30. 30Translation (BIO): Roles of mRNA, tRNA, rRNA Role and structure of ribosomesInsert
  31. 31Translation: Initiation, termination co-factors Post-translational modification of proteinsInsert
  32. 32Eukaryotic Chromosome Organization: Chromosomal proteins Single copy vs. repetitive DNA Supercoiling Heterochromatin vs. euchromatinInsert
  33. 33Eukaryotic Chromosome Organization: Telomeres, centromeresInsert
  34. 34Control of Gene Expression in Prokaryotes (BIO)  Operon Concept, Jacob–Monod Model Gene repression in bacteria Positive control in bacteriaInsert
  35. 35Control of Gene Expression in Eukaryotes: Transcriptional regulation DNA binding proteins, transcription factors Gene amplification and duplicationInsert
  36. 36Control of Gene Expression in Eukaryotes: Post-transcriptional control, basic concept of splicing (introns, exons) Cancer as a failure of normal cellular controls, oncogenes, tumor suppressor genesInsert
  37. 37Control of Gene Expression in Eukaryotes: Regulation of chromatin structure DNA methylation Role of non-coding RNAsInsert
  38. 38Recombinant DNA and Biotechnology (BIO): Gene cloning Restriction enzymesInsert
  39. 39DNA libraries Generation of cDNAInsert
  40. 40Hybridization Expressing cloned genesinsert
  41. 41Polymerase chain reactionI
  42. 42Gel electrophoresis and Southern blottingi
  43. 43DNA sequencingi
  44. 44Analyzing gene expression Determining gene functioni
  45. 45Stem cellsi
  46. 46Practical applications of DNA technology: medical applications, human gene therapy, pharmaceuticals, forensic evidence, environmental cleanup, agriculture Safety and ethics of DNA technologyi
  47. 47Evidence that DNA is Genetic Materiali
  48. 48Mendelian Concepts (BIO): Phenotype and genotype Gene Locus Allele: single and multiple Homozygosity and heterozygosity Wild-type Recessiveness Complete dominance Co-dominancei
  49. 49Menellian concepts: Incomplete dominance, leakage, penetrance, expressivity Hybridization: viability Gene pooli
  50. 50Significance of meiosis Important differences between meiosis and mitosisi
  51. 51Segregation of genes: Independent assortment Linkagei
  52. 52Segregation of genes ctd. Recombination: Single crossovers Double crossovers Synaptonemal complex Tetradi
  53. 53segregation of genes ctd: Sex-linked characteristics Very few genes on Y chromosome Sex determination Cytoplasmic/extranuclear inheritancei
  54. 54Mutation: General concept of mutation — error in DNA sequence Types of mutations: random, translation error, transcription error, base substitution, inversion, addition, deletion, translocation, mispairing Advantageous vs. deleterious mutation Inborn errors of metabolism Relationship of mutagens to carcinogensi
  55. 55Genetic drifti
  56. 56Synapsis or crossing-over mechanism for increasing genetic diversityi
  57. 57Analytic Methods (BIO): Hardy–Weinberg Principlei
  58. 58Analytic methods ctd: Testcross (Backcross; concepts of parental, F1, and F2 generations)i
  59. 59Analytic methods ctd: Gene mapping: crossover frequencies Biometry: statistical methodsi
  60. 60Natural Selection: Fitness concept Selection by differential reproduction Concepts of natural and group selection Evolutionary success as increase in percent representation in the gene pool of the next generationi
  61. 61Speciation: Polymorphism Adaptation and specialization Inbreeding Outbreeding Bottlenecksi
  62. 62Evolutionary time as measured by gradual random changes in genomei
  63. 63Bioenergetics/thermodynamics: Free energy/Keq Equilibrium constant Relationship of the equilibrium constant and ΔG°i
  64. 64Concentration: Le Châtelier’s Principlei
  65. 65Endothermic/exothermic reactionsi
  66. 66Free energy: G Spontaneous reactions and ΔG°i
  67. 67Phosphoryl group transfers and ATP -ATP hydrolysis ΔG << 0 -ATP group transfersi
  68. 68Biological oxidation-reduction: Half-reactions Soluble electron carriers Flavoproteinsi
  69. 69Carbs: Nomenclature and classification, common names Absolute configurationi
  70. 70carbs-epimers and anomersi
  71. 71Cyclic structure and conformations of hexosesi
  72. 72Hydrolysis of the glycoside linkage Monosaccharides Disaccharides Polysaccharidesi
  73. 73Glycolysis (aerobic), substrates & products o Feeder pathways: glycogen, starch metabolism Fermentation (anaerobic glycolysis)i
  74. 74Gluconeogenesis (BC)i
  75. 75Pentose phosphate pathway (BC)i
  76. 76Net molecular and energetic results of respiration processesi
  77. 77Regulation of metabolic pathways (BIO, BC) o Maintenance of a dynamic steady statei
  78. 78Regulation of glycolysis and gluconeogenesisi
  79. 79Metabolism of glycogen Regulation of glycogen synthesis and breakdown o Allosteric and hormonal control Analysis of metabolic controli
  80. 80Citric Acid Cycle (BIO, BC) Acetyl-CoA production (BC) Reactions of the cycle, substrates and products Regulation of the cycle Net molecular and energetic results of respiration processesi
  81. 81Metabolism of Fatty Acids and Proteins (BIO, BC)        Description of fatty acids (BC) Digestion, mobilization, and transport of fats Oxidation of fatty acids o o Saturated fats Unsaturated fats Ketone bodies (BC) Anabolism of fats (BIO) Non-template synthesis: biosynthesis of lipids and polysaccharides (BIO) Metabolism of proteins (BIO)i
  82. 82Oxidative Phosphorylation (BIO, BC) Electron transport chain and oxidative phosphorylation, substrates and products, general features of the pathwayi
  83. 83Electron transfer in mitochondria: NADH, NADPH Flavoproteins Cytochromesi
  84. 84ATP synthase, chemiosmotic coupling o Proton motive forcei
  85. 85Net molecular and energetic results of respiration processes: - regulation of phosphorylation - Mitochondria, apoptosis, oxidative stress (BC)i
  86. 86Hormonal Regulation and Integration of Metabolism (BC): Higher level integration of hormone structure and function Tissue specific metabolism Hormonal regulation of fuel metabolism Obesity and regulation of body massi
  87. 87Composition of membranes: Lipid components (BIO, BC, OC): Phospholipids (and phosphatids) -Steroids -Waxes Protein components Fluid mosaic model membrane dynamicsi
  88. 88Solute transport across membranes o Thermodynamic considerations 1. Osmosis: Colligative properties; osmotic pressure (GC) 2. Passive transport 3. Active transport; Sodium/potassium pumpi
  89. 89Membrane channels Membrane potential Membrane receptors Exocytosis and endocytosisi
  90. 90Intercellular junctions (BIO) Gap junctions Tight junctions Desmosomesi
  91. 91Defining characteristics of eukaryotic cells: membrane bound nucleus, presence of organelles, mitotic divisioni
  92. 92Nucleus: Compartmentalization, storage of genetic information Nucleolus: location and function Nuclear envelope, nuclear poresi
  93. 93Mitochondria: Site of ATP production Inner and outer membrane structure (BIO, BC) Self-replicationi
  94. 94Lysosomes: membrane-bound vesicles containing hydrolytic enzymes Golgi apparatus: general structure and role in packaging and secretion Peroxisomes: organelles that collect peroxidesi
  95. 95Endoplasmic reticulum o o o o o Rough and smooth components Rough endoplasmic reticulum site of ribosomes Double membrane structure Role in membrane biosynthesis Role in biosynthesis of secreted proteinsi
  96. 96Cytoskeleton (BIO) General function in cell support and movement Microfilaments: composition and role in cleavage and contractility Microtubules: composition and role in support and transport Intermediate filaments, role in support Composition and function of cilia and flagella Centrioles, microtubule organizing centersi
  97. 97tissues formed from eukaryotic cells epithelial cells connective tissue cellsi
  98. 98Cell Theory (BIO): History and development Impact on biologyi
  99. 99Prokaryotic domains: Archea, Bacteria Major classifications of bacteria by shape Bacilli (rod-shaped) Spirilli (spiral-shaped) Cocci (spherical) Lack of nuclear membrane and mitotic apparatus Lack of typical eukaryotic organelles Presence of cell wall in bacteria Flagellar propulsion, mechanismi
  100. 100Growth and Physiology of Prokaryotic Cells (BIO) Reproduction by fission High degree of genetic adaptability, acquisition of antibiotic resistance Exponential growth Existence of anaerobic and aerobic variants Parasitic and symbiotic Chemotaxisi
  101. 101Genetics of Prokaryotic Cells (BIO)  Existence of plasmids, extragenomic DNA Transformation: incorporation into bacterial genome of DNA fragments from external medium Conjugation Transposons (also present in eukaryotic cells)i
  102. 102Virus Structure (BIO) General structural characteristics (nucleic acid and protein, enveloped and nonenveloped) Lack organelles and nucleus Structural aspects of typical bacteriophage Genomic content — RNA or DNA Size relative to bacteria and eukaryotic cellsi
  103. 103Viral Life Cycle (BIO) Self-replicating biological units that must reproduce within specific host cell Generalized phage and animal virus life cycles Attachment to host, penetration of cell membrane or cell wall, and entry of viral genetic material Use of host synthetic mechanism to replicate virali
  104. 104Transduction: transfer of genetic material by viruses Retrovirus life cycle: integration into host DNA, reverse transcriptase, HIV Prions and viroids: subviral particlesi
  105. 105Mitotic structures Centrioles, asters, spindles Chromatids, centromeres, kinetochores Nuclear membrane breakdown and reorganization Mechanisms of chromosome movementi
  106. 106Mitotic process: prophase, metaphase, anaphase, telophase, interphasei
  107. 107Phases of cell cycle: G0, G1, S, G2, Mi
  108. 108Mitosis: Growth arrest Control of cell cycle Loss of cell cycle controls in cancer cellsi
  109. 109Biosignalling: oncogenes, apoptosisi
  110. 110Gametogenesis by meiosisi
  111. 111Ovum and sperm: Differences in formation Differences in morphology Relative contribution to next generationSperm enters into cytoplasm of oocyte -> oocyte does second meiotic division to become and OVUM and releases a second polar body.
    formation:
    spermatogenesis = occurs in the seminiferous tubules.
    oogenesis = occurs in the ovaries, then fallopian tubes
    morphology:
    - sperm = motile= flagella
    - egg= not motile= round
    relative contribution to next generation:
    - sperm contributes DNA only
    - egg contributes DNA + everything else(mitochondria, organelles, epigenetics)    Ovum and sperm: Differences in formation Differences in morphology Relative contribution to next generation
  112. 112Reproductive sequence: fertilization; implantation; development; birth1. fertilization: sperm + ovum → zygote (in fallopian tubes). CLEAVEAGE (division of cells in early embryo) begins when zygote is still in fallopian tube)
    2. implantation:
    ○ Zygote goes thru many cycles of mitosis, when zygote is comprised of 16+ cells it is called: a MORULA.
    § Any of these first 8 cells could become a human
    § BLASTOCYST: a mostly hollow ball filled with fluid and has small cell mass on one side;
    Blastocyst lodges in uterus (endometreum) in process called IMPLANTATION on 7th day after fertilization. At this point = pregnant.
    3. development:
    Blastocyst implants in uterine wall and fuses with uterine tissue to form the PLACENTA
    After implantation, the placenta begins secreting the peptide hormone HUMAN CHORIONIC GONADOTROPIN (HCG)
    Formation of the GASTRULA occurs in the third week after fertilization in a process
    organogenesis
    Birth:
    Switch from getting oxygen from mom's blood → breathing.
    Switch from getting nutrients from mom's blood → suckling.
    Fetal circulation (which bypasses lungs and liver) → normal circulation (by closing off ducts and openings).
  113. 113Embryogenesis (BIO)  Stages of early development (order and general features of each): Fertilization Cleavage Blastula formation Gastrulation Neurulation1. FERTILIZATION
    Sperm meets egg
    Acrosomal reaction causes sperm to penetrate egg
    Cortical reaction causes egg to prevent additional sperm from penetrating
    Egg completes meiosis II
    Sperm and egg nuclei fuse
    2. CLEAVAGE
    Normal mitotic cell divisions: cell grows then divides, grows again, then divides.
    Cleavage = mitotic divisions without cell growth.
    3. blastula formation
    fertilization produces zygote
    cleavage produces a solid ball called the morula
    morula hollows out into the blastula or blastocyst
    blastula occurs in non-mammals
    blastocyst occurs in mammals
    blastocyst implants
    4. gastrulation
    cell movements to form germ layers
    5. neurulation
    ectoderm → brain and spinal cord
    the ectoderm does so by folding into a tube
  114. 114Gastrulation First cell movements Formation of primary germ layers (endoderm, mesoderm, ectoderm)gastrulation,
    - first cell movements:
    Cells from the surface migrate inwards.
    gastrulation occurs slightly different for different animals. Some by invagination, some by migration, some by splitting.
    In mammals, the cells start migrating inward at the primitive streak.
    The cells that migrate inwards form the endoderm.
    The cells that remain outside is the ectoderm.
    The cells in the middle are the mesoderm.
  115. 115Major structures arising out of primary germ layers Neural crest Environment–gene interaction in developmentendoderm = innermost layer = guts, lungs, and digestive internal organs (liver, pancreas).
    mesoderm = middle layer = muscle, blood and bone tissues, and interal organs (kidney and gonads).
    ectoderm = outermost layer = skin and nerves (including the brain).
  116. 116Cell specialization: Determination Differentiation Tissue typesdetermination = irreversible commitment to become a certain cell type. 1st
    differentiation = becoming a cell type and adopting its specialized functions. 2nd
    or
    § Past the 8 cell stage, the cells become different from each other due to cell-cell communication. The process where a cell becomes committed to a specialized developmental path = DETERMINATION
    The specialization that occurs at the end of development forming a specialized tissue cell = DIFFERENTIATION.
    tissue types: muscle, nervous, connective, epithelial
  117. 117Cell–cell communication in development Cell migrationThru INDUCTION (one group of cells changing the behavior of an adjacent group of cells),
    the NOTOCHORD (made from mesoderm) -> overlying ectoderm to thicken and form neural plate. Notochord degenerates and neural tube forms from neural place to become spinal cord, brain, most of nervous system. ;
    cells of ectoderm closest to neural tube: NEURAL CREST
    - These cells mostly function as accessory cells to the nervous system like Schwann cells . They also give rise to part of endocrine organs.
    - Neural crest cells undergo cell migration to travel to other parts of body.
    The FIRST CELL MOVEMENTS occur as cells begin to slowly move about the embryo. In mammals a primitive streak is formed, cells destined to b in mesoderm migrate there.
  118. 118Pluripotency: stem cells Gene regulation in development Programmed cell death Existence of regenerative capacity in various species Senescence and agingpluripotent stem cells can become anything
    some organs (liver, blood, skin) hv multipotent stem cells that can regenerate if needed
    programmed cell death is normal part of development ex spaces btwn fingers
    pretty much any step in gene regulation occurs in development too
    SENESCENCE: cells stop being able to grow in response to environmental stressors and are ultimately cleared away by immune cells. Necessary for development, also part of aging
  119. 119Nervous System: High level control and integration of body systems Adaptive capability to external influences other stuff (me): refractory period, A single neuron secretes ___ NT, a neuron can respond to ___ types of NT, a given synapse can inhibit ___ excite:yes, that.
    also other stuff:
    Once ap begins, there is a period of time called absolute refractory period where no stimulus will create another AP
    Relative refractory period: time during which only an abnormally large stimulus will create an AP
    A single neuron usually secretes on one NT, however a neuron may be able to respond to multiple types of NT
    Any given synapse is designed to inhibit or excite but not both. Cannot change.;
  120. 120Organization of vertebrate nervous system Sensor and effector neuronsCNS: brain and spinal cord
    PNS: peripheral nervous system
    Sensory neurons- receive signals from receptor cell that interacts with the environment
    Motor neurons (same as effector neurons i think) - carry signals to a muscle or gland called the effector .
  121. 121Sympathetic and parasympathetic nervous systems: antagonistic controlPNS is further divided in: somatic nervous system (voluntary movement// conscious control) and autonomic nervous system (involuntary)
    ANS divided into: sympathetic (fight or flight) and parasympathetic (rest or digest)
    - ANS is under antagonistic control i.e. sympathetic and parasympathetic balance each other
  122. 122reflexes: Feedback loop, reflex arc Role of spinal cord and supraspinal circuitsReflex arc: sensory -> interneuron -> motor neuron -> effector
    Inhibitory input from supraspinal circuits: descending from CNS, can decrease the sensitivity & speed of the reflex so it proceeds smoothly and only when needed    reflexes: Feedback loop, reflex arc Role of spinal cord and supraspinal circuits
  123. 123integration with endocrine system: feedback controlHypothalamus and pituitary gland = major site for nervous and endocrine system interaction, allows for feedback control of hormone levels in body;
  124. 124Cell body: site of nucleus, organelles Dendrites: branched extensions of cell body Axon: structure and function Myelin sheath, Schwann cells, insulation of axon Nodes of Ranvier: propagation of nerve impulse along axon Synapse: site of impulse propagation between cellsAxon hillocks: site of connection btwn cell body and axon generates AP in all directions including down the axon (if signal received by dendrites sum to produce a large enough change in voltage);
    Communication btwn neurons and synapse:
    - Electrical synapses: uncommon, made of gap junctions btwn cells, cardiac muscle, visceral smooth muscle and v few neurons in CNS have this
    - Chemical synapse: more common, space btwn two neurons that are crossed by Neurotransmitters, they are unidirectional; Ex. Motor end plate: connection btwn a neuron and muscle (chemical synapse);
    Nodes of Ranvier: tiny gaps btwn myelinated areas. Myelin acts as insulator around axon, increasing resistance to the passage of ions thru membrane . Ap jumps from one node of Ranvier to the next (fast)= saltatory conduction;
    White matter: areas of nervous system that are composed of myelinated axons of neurons (cuz they look white)
    Grey matter: bundles of cell bodies of neurons;
  125. 125Synaptic activity: transmitter moleculesNT used by all preganglionic neurons in the ANS and postganglionic neurons in parasympathetic is : acetylcholine (receptor is cholinergic- nicotonic or muscaneric));
    Postganglionic neurons in sympathetic use this NT: epi or norepi (aka adrenaline and noradrenaline) (use adrenergic receptors)
  126. 126Resting potential: electrochemical gradient Action potential: Threshold, all-or-none Sodium/potassium pumpResting potential :-70 mV (value of resting membrane potential is determined by the equilibrium potential of K+ !);
    Membrane contains sodium/ potassium pump: moves 3 Na out of cell and 2 K+ back into cell ;
    Voltage gated sodium pumps (more dependent on voltage, na+ flow into cell) and voltage gates potassium channels (take longer to open, K+ flows out of cell):
  127. 127Excitatory and inhibitory nerve fibers: summation, frequency of firingexcitatory= depolarizing effect
    Inhibitory= hyperpolarizing effect
    Summation (spatial and temporal):
    -Spatial summation- when multiple dendrites receive signals at same time
    -Temporal summation- adds up effects of signals that are received by a single dendrite;;
    Intensity of stimulus is coded by: frequency of firing;
  128. 128Glial cells, neurogliaGlial cells/ neuroglia: support cells
    Capable of cellular division
    If there is brain injury, they multiply to fill space in CNS
    Many types. One in PNS is Schwann cells which produce electrically insulating sheaths called myelin (myelin is also in CNS);
  129. 129Electrochemistry (GC):  Concentration cell: direction of electron (?) flow, Nernst equationCharge of ion = n
    E0 is the standard cell potential, the voltage that exists when ion concentrations are equal in both parts of the cell
    Q is ratio products to reactants (only K+ intracellular/ K + extracellular);
    When temp is constant, whole expression RT/F is constant    Electrochemistry (GC):  Concentration cell: direction of electron (?) flow, Nernst equation
  130. 130Biosignalling (BC) Gated ion channels -Voltage gated -Ligand gated Receptor enzymes G protein-coupled receptorsWhat happens to NT after attached to receptor: NT remains attached to receptor for part of a second then released into synaptic cleft. NT may be destroyed by enzyme in matrix of synaptic cleft, directly absorbed by presynaptic cell by active transport, or NT may diffuse out of synaptic cleft;
    G proteins
    commonly initiate second messenger system. When a receptor is stimulated by NT, part of g protein, a subunit, breast free. A subunit may: activate separate specific ion channels, activate second messenger (like cyclic amp or cyclic GMP), activate intracellular enzymes and activate gene transcription;
  131. 131Lipids (BC, OC)  Description; structure -Steroids -Terpenes and terpenoidsLipids:
    • Nonpolar/ hydrophobic
    • Need to be transported in blood via lipoproteins - lipid protein surrounded by phospholipids to get past member.
    • Store the most energy bcuz lots of C-H bonds (v. high in energy)
    ○ Greater ratio of lipid to protein, the lower the density ;
    Plays 3 major roles:
    ○ Energy storage
    ○ Cell organization and structure
    ○ Basis for vitamins and hormones;
    some types:
    Steroid: 4 ringed structures
    ex. Hormones, vitamin D, cholesterol
    Terpenes: unsaturated, cyclic carbons.. include vitamin A
  132. 132Endocrine System: Hormones and Their Sources (BIO) Function of endocrine system: specific chemical control at cell, tissue, and organ level Definitions of endocrine gland, hormone Major endocrine glands: names, locations, products Major types of hormones Neuroendrocrinology ― relation between neurons and hormonal systemsmaybe put at end or just decide to memorize in a bunch
  133. 133Endocrine System: Mechanisms of Hormone Action (BIO): Cellular mechanisms of hormone actionHormones are released by: ENDOCRINE GLANDS directly into the blood stream
    - Effect of endocrine system to alter metabolic activities, regulate growth and development and guide reproduction
    ○ Works with nervous system;
    EXOCRINE GLANDS: release enzymes to the external environment through ducts. Ex. Mucous, sudoriferous (sweat)
    Ex. Pancreas acts as both exocrine gland (releases digestive enzymes thru the pancreatic duct) and an endocrine gland (releases insulin and glucagon into the blood)
  134. 134Transport of hormones: blood supply Specificity of hormones: target tissuei
  135. 135hormones: Integration with nervous system: feedback control Regulation by second messengersi
  136. 136Respiratory System (BIO) General function -Gas exchange, thermoregulation -Protection against disease: particulate matteri
  137. 137Structure of lungs and alveolii
  138. 138Breathing mechanisms: Diaphragm, rib cage, differential pressure Resiliency and surface tension effects-
  139. 139Thermoregulation: nasal and tracheal capillary beds; evaporation, panting Particulate filtration: nasal hairs, mucus/cilia system in lungs-
  140. 140Alveolar gas exchange: Diffusion, differential partial pressure Henry’s Law (GC)-
  141. 141Respiratory: -pH controli
  142. 142Respiratory -Regulation by nervous control o CO2 sensitivity-
  143. 143Circulatory System (BIO): Functions: circulation of oxygen, nutrients, hormones, ions and fluids, removal of metabolic waste Role in thermoregulation-
  144. 144Four-chambered heart: structure and function-
  145. 145Endothelial cells-
  146. 146Systolic and diastolic pressure-
  147. 147Pulmonary and systemic circulation-
  148. 148Arterial and venous systems (arteries, arterioles, venules, veins): Structural and functional differences Pressure and flow characteristics-
  149. 149Capillary beds: Mechanisms of gas and solute exchange Mechanism of heat exchange Source of peripheral resistance-
  150. 150Composition of blood (respiratory): Plasma, chemicals, blood cells Erythrocyte production and destruction; spleen, bone marrow Regulation of plasma volume-
  151. 151Oxygen transport by blood: -Hemoglobin, hematocrit -Oxygen content -Oxygen affinity Carbon dioxide transport and level in blood-
  152. 152Nervous and endocrine control-
  153. 153clotting, coagulation mechanismsi
  154. 154Lymphatic System (BIO): Structure of lymphatic system-
  155. 155Major functions lymph system: Equalization of fluid distribution Transport of proteins and large glycerides Production of lymphocytes involved in immune reactions Return of materials to the blood-
  156. 156Innate (non-specific) vs. adaptive (specific) immunity-
  157. 157Adaptive immune system cells: T-lymphocytes B-lymphocytes-
  158. 158Innate immune system cells: Macrophages Phagocytes-
  159. 159Tissues Bone marrow Spleen Thymus Lymph nodes-
  160. 160antigen/ antibody structure of antibody molecule antigen presentation antigen-antibody recognition-
  161. 161clonal selection-
  162. 162Recognition of self vs. non-self, autoimmune diseases-
  163. 163Major histocompatibility complex-
  164. 164Digestive system: Ingestion: Saliva as lubrication and source of enzymes Ingestion; esophagus, transport function-
  165. 165Stomach Storage and churning of food Low pH, gastric juice, muscal protection against self-destruction Production of digestive enzymes, site of digestion Structure (gross)-
  166. 166Liver Structural relationship of liver within gastrointestinal system Production of bile Role in blood glucose regulation, detoxification-
  167. 167Bile Storage in gall bladder Function-
  168. 168Pancreas Production of enzymes Transport of enzymes to small intestine-
  169. 169Small Intestine Absorption of food molecules and water Function and structure of villi Production of enzymes, site of digestion Neutralization of stomach acid Structure (anatomic subdivisions)-
  170. 170Large Intestine Absorption of water Bacterial flora Structure (gross)-
  171. 171Rectum: storage and elimination of waste, feces-
  172. 172Muscular control o Peristalsis-
  173. 173Endocrine control Hormones Target tissues-
  174. 174Nervous control: the enteric nervous system-
  175. 175Excretory System (BIO)  Roles in homeostasis Blood pressure Osmoregulation Acid–base balance Removal of soluble nitrogenous waste-
  176. 176Kidney structure Cortex Medulla Nephron structure Glomerular filtration Secretion and reabsorption of solutes Concentration of urine Counter-current multiplier mechanism Storage and elimination: ureter, bladder, urethra Osmoregulation: capillary reabsorption of H2O, amino acids, glucose, ions Muscular control: sphincter muscle-
  177. 177Male and female reproductive structures and their functions Gonads Genitalia Differences between male and female structures-
  178. 178Hormonal control of reproduction Male and female sexual development Female reproductive cycle Pregnancy, parturition, lactation Integration with nervous control-
  179. 179muscle: important functions Support: mobility Peripheral circulatory assistance Thermoregulation (shivering reflex)-
  180. 180Structure of three basic muscle types: striated, smooth, cardiac-
  181. 181Muscle structure and control of contraction T-tubule system Contractile apparatus Sarcoplasmic reticulum Fiber type Contractile velocity of different muscle types-
  182. 182Regulation of cardiac muscle contraction-
  183. 183Oxygen debt: fatigue Nervous control: Motor neurons: Neuromuscular junction, motor end plates Sympathetic and parasympathetic innervation Voluntary and involuntary muscles-
  184. 184Specialized Cell - Muscle Cell (BIO)       Structural characteristics of striated, smooth, and cardiac muscle Abundant mitochondria in red muscle cells: ATP source Organization of contractile elements: actin and myosin filaments, crossbridges, sliding filament model Sarcomeres: “I” and “A” bands, “M” and “Z” lines, “H” zone Presence of troponin and tropomyosin Calcium regulation of contraction-
  185. 185Skeletal System (BIO): Functions Structural rigidity and support Calcium storage Physical protection Skeletal structure Specialization of bone types, structures Joint structures Endoskeleton vs. exoskeleton Bone structure Calcium/protein matrix Cellular composition of bone Cartilage: structure and function Ligaments, tendons Endocrine control-
  186. 186Skin System (BIO): Structure Layer differentiation, cell types Relative impermeability to water Functions in homeostasis and osmoregulation Functions in thermoregulation Hair, erectile musculature Fat layer for insulation Sweat glands, location in dermis Vasoconstriction and vasodilation in surface capillaries Physical protection Nails, calluses, hair Protection against abrasion, disease organisms-
  187. 187—

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Flashcards on MCAT Biology, created by aly chris on 22/05/2017.
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