MCAT Biology Review 2021-2022 PDF

Table of Contents MCAT Biology Review Cover Title Page Copyright Information The Kaplan MCAT Review Team Getting Started Checklist Preface About Scientific American About the MCAT How This Book Was Created Using This Book Studyin...

Table of Contents MCAT Biology Review Cover Title Page Copyright Information The Kaplan MCAT Review Team Getting Started Checklist Preface About Scientific American About the MCAT How This Book Was Created Using This Book Studying for the MCAT Chapter 1: The Cell 1.1 Cell Theory 1.2 Eukaryotic Cells 1.3 Classification and Structure of Prokaryotic Cells 1.4 Genetics and Growth of Prokaryotic Cells 1.5 Viruses and Subviral Particles Chapter 2: Reproduction 2.1 The Cell Cycle and Mitosis 2.2 Meiosis 2.3 The Reproductive System Chapter 3: Embryogenesis and Development 3.1 Early Developmental Stages 3.2 Mechanisms of Development 3.3 Fetal Circulation 3.4 Gestation and Birth Chapter 4: The Nervous System 4.1 Cells of the Nervous System 4.2 Transmission of Neural Impulses 4.3 Organization of the Human Nervous System Chapter 5: The Endocrine System 5.1 Mechanisms of Hormone Action  5.2 Endocrine Organs and Hormones Chapter 6: The Respiratory System 6.1 Anatomy and Mechanism of Breathing 6.2 Functions of the Respiratory System Chapter 7: The Cardiovascular System 7.1 Anatomy of the Cardiovascular System 7.2 Blood - 7.3 Physiology of the Cardiovascular System L Chapter 8: The Immune System 8.1 Structure of the Immune System 8.2 The Innate Immune System 8.3 The Adaptive Immune System 8.4 The Lymphatic System Chapter 9: The Digestive System 9.1 Anatomy of the Digestive System 9.2 Ingestion and Digestion 9.3 Accessory Organs of Digestion 9.4 Absorption and Defecation Chapter 10: Homeostasis 10.1 The Excretory System 10.2 Skin Chapter 11: The Musculoskeletal System 11.1 The Muscular System 11.2 The Skeletal System Chapter 12: Genetics and Evolution 12.1 Fundamental Concepts of Genetics 12.2 Changes in the Gene Pool 12.3 Analytical Approaches in Genetics 12.4 Evolution Glossary Art Credits Source: AAMC. 2019. Summary of MCAT Total and Section Scores. Accessed November 2019. https://students-residents.aamc.org/advisors/article/percentile-ranks- for-the-mcat-exam/ 1 : 1 now - 1. What are the four fundamental tenets of the cell theory? Cell is the smallest unit of living things All is made of cells organism one or more cell arises from other cell by cellular division cell vies DNA to transfer information  head hydrophilic tail Edophillic 9 2 - cell S moor's ninugI - 3. &. 5 6. β F , 8 / mitosis divide divide nucleus cytokinesis , cells Caytoplasm] T how a Echaryotic cells reproduce into 2 cells 9 hair-like structure > -  movirsmovos cell ↑ 10. 11. 11 , ver ii , s - ⑳ente tube - 19. rig supporting > - tissue 1. Briefly describe the functions of each of the organelles listed below: Nucleus: Mitochondrion: Lysosome:  Rough endoplasmic reticulum: Smooth endoplasmic reticulum: Golgi apparatus: Peroxisome: 2. A child is diagnosed with an enzyme deficiency that prevents the production of hydrogen peroxide. What would the likely outcome be of such a deficiency? 3. What are the predominant proteins in each cytoskeletal element? Microfilaments: Microtubules: Intermediate filaments: 4. How do the cytoskeletal structures of centrioles and flagella differ? 5. Classify each of the following cells as epithelial cells or connective tissue: Fibroblasts, which produce collagen in a number of organs: Endothelial cells, which line blood vessels: α-cells, which produce glucagon in the pancreas: Osteoblasts, which produce osteoid, the material that hardens into bone: Chondroblasts, which produce cartilage: 1. In what ways are Archaea similar to bacteria? In what ways are Archaea similar to eukaryotes? Similar to bacteria: Similar to eukaryotes: 2. What are the three common shapes of bacteria? 3. Compare and contrast the metabolisms of aerobic and anaerobic bacteria: (Note: Put “yes” or “no” in each box.) 4. What difference between the envelopes of gram-positive and gram-negative bacteria make gram-positive bacteria more susceptible to antibiotics such as penicillin? 5. How do the structures of eukaryotic and prokaryotic flagella differ? Eukaryotic: Prokaryotic: Adapted from Sorg, R. A., Lin, L., Van Doorn, G. S., Sorg, M., Olson, J., Nizet, V., & Veening, J. W. (2016). Collective r communities By intracellular antibiotic deactivation. PLoS Biology, 14(12), e2000631. 1. Briefly describe the three mechanisms of bacterial genetic recombination: Transformation: Conjugation: Transduction: 2. What are the four phases of the bacterial growth curve? What are the features of each phase? α β 1. Why are viruses considered obligate intracellular parasites? 2. Coronavirus, which causes the common cold, is described as an enveloped, single-stranded positive-sense RNA virus. What does this indicate about the virus? 3. Briefly describe the pathway of retroviral nucleic acids from infection of a host cell to release of viral progeny: 4. What are the differences between the lytic and lysogenic cycles? Lytic cycle: Lysogenic cycle: 5. How do prions cause disease? β α β α α β  β β β  somatic - not involved with reproductive system somatic of cell- Types somatic ↳ somatic Germ cell - reproductive system. Telophan anaphase Prophase metaphore , , , e Y. G , ,e > - ↳ Check onlarge DNA replication  ↳ to stop cell cycle. Adapted from: Snyder EL, Meade BR, Saenz CC, Dowdy SF (2004). Treatment of terminal peritoneal carcinomatosis by a activating peptide. PLOS Biology 2(2): e36. https://doi.org/10.1371/journal.pbio.0020036. 1. What are the five stages of the cell cycle? What happens in each stage? 2. What are the four phases of mitosis? What happens in each phase?  Homologeon chromosome - she siter chromatids core for but does not save gave diff allele. replication a sae /tetrads or synaptoneal. miosic e : reduce no of Choum m 2 : Sepal Chores The selfish gene. 1. What is the number and ploidy of the daughter cells produced from meiosis I? From meiosis II? Meiosis I: Meiosis II: 2. What is the difference between homologous chromosomes and sister chromatids? Homologous chromosomes: Sister chromatids: 3. For each phase of meiosis I listed below, what are the differences from the analogous phase of mitosis? endocrine a miculitis exocr horrors. r enzyme T or Bonvost microtubules.  has cillia - > - fertilisation G happens here. - fir nalen of ogg 1. What are the functions of interstitial cells of Leydig and Sertoli cells? Interstitial cells of Leydig: Sertoli cells: 2. During which phase of meiosis is a primary oocyte arrested? During which phase of meiosis is a secondary oocyte arrested? Primary oocyte: Secondary oocyte: 3. What is the acrosome? What organelle forms the acrosome? 4. Which hormones are key to sexual differentiation in a fetus with XY genotype? Describe the expected phenotype if receptors to these hormones are absent. 5. What are the four phases of the female menstrual cycle? What are the features and relative hormone concentrations of each phase? (Note: Draw in symbols to signify the levels of each hormone, such as ↑, =, and ↓) → → → → → → → → → → → → → → → → 1. What is the difference between determinate and indeterminate cleavage? Determinate cleavage:  Indeterminate cleavage: 2. From zygote to gastrula, what are the various stages of development? 3. During which stage of development does implantation occur? 4. What are the primary germ layers, and what organs are formed from each? 5. What is induction and how does it influence development? 6. What tissues do neural crest cells develop into? Adapted from Xi, J., Wu, Y., Li, G., Ma, L., Feng, K., Guo, X., … Kang, J. (2017). Mir-29b mediates the neural tube versu decision during embryonic stem cell neural differentiation. Stem Cell Reports, 9(2), 571-586. β 1. What is the difference between determination and differentiation? Determination: Differentiation: 2. What are the three types of potency? What lineages can a cell of each type differentiate into? 3. What are the four types of cell–cell communication? 4. What is the difference between apoptosis and necrosis? Apoptosis: Necrosis: 1. What is the oxygenation status of the blood in the umbilical arteries? In the umbilical vein? Umbilical arteries: Umbilical vein: 2. What are the three fetal shunts? What vessels or heart chambers do they connect? What organ does each shunt bypass? 1. What are some of the key developmental features of each trimester? First trimester: Second trimester: Third trimester: 2. What occurs in each of the three phases of birth? Adapted from: Giampà, C., Laurenti, D., Anzilotti, S., Bernardi, G., Menniti, F. S., & Fusco, F. R. (2010). Inhibition o phosphodiesterase pde10a ameliorates striatal and cortical pathology in r6/2 mouse model of Huntingtons disease doi:10.1371/journal.pone.0013417. 1. For each of the following neuron structures, provide a brief description of its purpose: Axon: Axon hillock: Dendrite: Myelin sheath: Soma: Synaptic bouton: 2. What is a collection of cell bodies called in the CNS? In the PNS? CNS: PNS: 3. Which two types of glial cells, if not properly functioning, will make an individual most susceptible to a CNS infection? 4. Guillain-Barré syndrome (GBS) is an autoimmune disease that causes demyelination in the peripheral nervous system. What type of glial cell is being targeted in GBS? 1. What neural structure initiates the action potential? 2. What entity maintains the resting membrane potential? What is the approximate voltage of the resting membrane  potential? 3. What is the difference between temporal and spatial summation? Temporal summation: Spatial summation: 4. During the action potential, which ion channel opens first? How is this ion channel regulated? What effect does the opening of this channel have on the polarization of the cell? Ion channel: Regulation: Effect on polarization: 5. During the action potential, which ion channel opens second? How is this ion channel regulated? What effect  does the opening of this channel have on the polarization of the cell? Ion channel: Regulation: Effect on polarization: 6. What is the difference between the absolute and relative refractory period? Absolute refractory period: Relative refractory period: 7. What ion is primarily responsible for the fusion of neurotransmitter-containing vesicles with the nerve terminal membrane? 8. What are the three main methods by which a neurotransmitter’s action can be stopped? 1. What parts of the nervous system are in the central nervous system (CNS)? Peripheral nervous system (PNS)? CNS: PNS: 2. What do afferent neurons do? Efferent neurons? Afferent:  Efferent: 3. What functions are accomplished by the somatic nervous system? The autonomic nervous system? Somatic: Autonomic: 4. What are the effects of the sympathetic nervous system? The parasympathetic nervous system? Sympathetic: Parasympathetic: 5. What is the pathway of neural impulses in a monosynaptic reflex? In a polysynaptic reflex? Monosynaptic reflex: Polysynaptic reflex: 1. Compare and contrast peptide and steroid hormones based on the following criteria: 2. How are amino acid–derivative hormones synthesized? 3. What is the difference between a direct and a tropic hormone? Direct hormone: Tropic hormone: → → → → Adapted from Park, S., Han, C. R., Park, J. W., Zhao, L., Zhu, X., Willingham, M., … Cheng, S. Y. (2017). Defective erythr mutations of the thyroid hormone receptor α gene. PLoS Genetics, 13(9), e1006991. doi:10.1371/journal.pgen.  α β δ α β δ α β α β δ 1. For each of the hypothalamic releasing hormones listed below, what hormone(s) does each affect in the anterior pituitary? On which organ does each pituitary hormone act? What hormone(s) are released by the target organs? 2. Which two hormones are primarily involved in calcium homeostasis? Where does each come from, and what effect does each have on blood calcium concentrations? 3. Which endocrine tissue synthesizes catecholamines? What are the two main catecholamines it produces? 4. Which two pancreatic hormones are the major drivers of glucose homeostasis? Where does each come from, and what effect does each have on blood glucose concentrations? 5. Which three hormones are primarily involved in water homeostasis? Where does each come from, and what effect does each have on blood volume and osmolarity?  α β δ *Note that a decrease in dopamine from the hypothalamus promotes prolactin secretion. α β β β β 1. List the structures in the respiratory pathway, from where air enters the nares to the alveoli. 2. Which muscle(s) are involved in inhalation? Exhalation? Inhalation: Exhalation: 3. What is the purpose of surfactant? 4. What is the mathematical relationship between vital capacity (VC), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and tidal volume (TV)? 5. If blood levels of CO2 become too low, how does the brain alter the respiratory rate to maintain homeostasis? Adapted from Zelko, I. N., Zhu, J., & Roman, J. (2018). Role of SOD3 in silica-related lung fibrosis and pulmonary remodeling. Respiratory Research, 19(1), 221. doi:10.1186/s12931-018-0933-6. 1. What are some of the mechanisms used in the respiratory system to prevent infection? 2. What is the chemical equation for the bicarbonate buffer system? 3. Respiratory failure refers to inadequate ventilation to provide oxygen to the tissues. How would the pH change in respiratory failure? Adapted from Tang X-L, Sanganalmath SK, Sato H, Bi Q, Hunt G, Vincent RJ, et al. (2011) Atorvastatin therapy during the attenuates left ventricular dysfunction and remodeling after myocardial infarction. PLoS One 6(9): e25320 https://doi.org/10.1371/journal.pone.0025320. β β 1. Starting from entering the heart from the venae cavae, what are the four chambers through which blood passes in the heart? Which valve prevents backflow into each chamber? 2. Starting with the site of impulse initiation, what are the structures in the conduction system of the heart? 3. Compare and contrast arteries, capillaries, and veins: 4. Why does the right side of the heart contain less cardiac muscle than the left side? 5. If all autonomic input to the heart were cut, what would happen? 1. What are the components of plasma? 2. An individual with B+ blood is in an automobile accident and requires a blood transfusion. What blood types could he receive? The same individual is so thankful that, after recovery, he decides to donate blood. To which blood types could he donate? Could receive from: Could donate to: 3. What does a hematocrit measure? What are the units for hematocrit? 4. Which types of leukocytes are involved in the specific immune response? 5. Where do platelets come from? 6. Which cell type(s) in blood contain nuclei? Which do not? Contain nuclei: Do not contain nuclei:  Δ Δ α β 1. In bacterial sepsis (overwhelming bloodstream infection), a number of capillary beds throughout the body open simultaneously. What effect would this have on the blood pressure? Besides the risk of infection, why might sepsis be dangerous for the heart? 2. What is the chemical equation for the bicarbonate buffer system? What enzyme catalyzes this reaction? 3. Where should you look on the oxyhemoglobin dissociation curve to determine the amount of oxygen that has been delivered to tissues? 4. What direction does the oxyhemoglobin dissociation curve shift as a result of exercise? What physiological changes cause this shift and why? 5. Exposure of which subendothelial compounds start the coagulation cascade? What protein helps stabilize the clot? Starts the cascade: Stabilizes the clot: Δ 1. What are the differences between innate and adaptive immunity? Innate immunity: Adaptive immunity: 2. Compare and contrast B- and T-cells: 3. Which cells are considered granulocytes? Which are considered agranulocytes? Granulocytes: Agranulocytes: 1. For each of the noncellular nonspecific immune defenses listed below, provide a brief description of its immunologic function: Skin: Defensins: Lysozyme:  Mucus: Stomach acid: Normal gastrointestinal flora: Complement: 2. Which cells are professional antigen-presenting cells? 3. What are the differences between MHC-I and MHC-II? MHC-I: MHC-II: 4. What stimulus activates each of the following types of cells? Natural killer cells: Neutrophils: Eosinophils: Basophils and mast cells: γ β Adapted from Welz, M., Eickhoff, S., Abdullah, Z., Trebicka, J., Gartlan, K. H., Spicer, J. A., & Kastenmüller, W. (2018). Pe protects from lethal endothelial damage during fulminant viral hepatitis. Nature Communications, 9(1), 4805. doi:10.103 07213-x. 1. For each of the lymphocytes listed below, what are its main functions? Plasma cell: Memory B-cell:  Helper T-cell: Cytotoxic T-cell: Suppressor (regulatory) T-cell: Memory T-cell: 2. What are the three main effects circulating antibodies can have on a pathogen? 3. How do antibodies become specific for a given antigen? 4. A T-cell appropriately passes through positive selection, but then inappropriately passes through negative selection. What will this T-cell be reactive toward? 5. Which cells account for the fact that the secondary response to a pathogen is much more rapid and robust than the primary response? 6. What is the difference between active and passive immunity? Active immunity: Passive immunity: 1. Filariasis is the name for an infection with a member of a certain group of parasites, most notably Wuchereria bancrofti. This parasite resides in lymph nodes and causes blockage of flow. If an individual had a W. bancrofti infection in the lymph nodes of his or her thigh, what would likely happen? 2. What structure is primarily responsible for returning materials from lymphatic circulation to the cardiovascular system? Adapted from Lundåsen T, Andersson E-M, Snaith M, Lindmark H, Lundberg J, Östlund-Lindqvist A-M, et al. (2012) Inhib acid transporter slc10a2 improves triglyceride metabolism and normalizes elevated plasma glucose levels in mice. PLoS https://doi.org/10.1371/journal.pone.0037787. 1. What is the difference between mechanical and chemical digestion?  Mechanical digestion: Chemical digestion: 2. Trace the path of food through the body, starting with ingestion and ending with excretion of feces: 3. What effect does the parasympathetic nervous system have on the digestive system? What effect does the sympathetic nervous system have? Parasympathetic nervous system: Sympathetic nervous system: 1. What two main enzymes are found in saliva? What do these enzymes do? 2. For each of the cell types below, list the major secretions of the cell and the functions of these secretions. 3. For each of the following substances, determine whether it is a digestive enzyme or a hormone and briefly summarize its functions. 4. How do bile and pancreatic lipase work together to digest fats? *Note: Bile is not an enzyme, but is involved in mechanical digestion of fats. *Note: Bile is not an enzyme, but is involved in mechanical digestion of fats. *Note: Bile is not an enzyme, but is involved in mechanical digestion of fats. *Note: Bile is not an enzyme, but is involved in mechanical digestion of fats. 1. List at least one pancreatic enzyme that digests each of the three major classes of biomolecules:  Carbohydrates: Proteins: Fats: 2. What are the main components of bile? 3. Where is bile synthesized? Where is bile stored? Where does bile carry out its digestive function? Synthesized: Stored: Carries out function: 4. List at least four functions of the liver: 5. The accessory organs of digestion originate from which primary germ layer? 1. What are the two circulatory vessels in a villus? What biomolecules are absorbed into each? 2. What are the four fat-soluble vitamins? 3. What are the three sections of the small intestine, in order? What are the three sections of the large intestine, in order? , , Small intestine: , , Large intestine: 4. Vibrio cholera causes a severe infection in the intestines, leading to massive volumes of watery diarrhea—up to 20 liters per day. Given these symptoms, does cholera likely impact the small intestine or the large intestine? Adapted from Krishnan, D., Pan, W., Beggs, M. R., Trepiccione, F., Chambrey, R., Eladari, D., Cordat, E., Dimke, H., … Alex Deficiency of carbonic anhydrase ii results in a urinary concentrating defect. Frontiers in Physiology 8, 1108. doi:10.3389/ 1. List the structures in the excretory pathway, from where filtrate enters the nephron to the excretion of urine from the body. 2. List the vessels in the renal vascular pathway, starting from the renal artery and ending at the renal vein. 3. What arm of the nervous system is responsible for contraction of the detrusor muscle? 4. What are the three processes by which solutes are exchanged between the filtrate and the blood? What happens in each process? 5. For each segment of the nephron listed below, what are its major functions? Bowman’s capsule: Proximal convoluted tubule: Descending limb of the loop of Henle: Ascending limb of the loop of Henle: Distal convoluted tubule: Collecting duct: 1. What is the predominant cell type in the epidermis? 2. What are the layers of the epidermis, from superficial to deep? 3. What are the layers of the dermis, from superficial to deep? 4. What are some mechanisms the body uses to cool itself? What are some mechanisms the body uses to retain heat? Cooling: Retaining heat: Adapted from Ranatunga K. W. (2018). Temperature effects on force and actin⁻myosin interaction in muscle: a look b experimental findings. International Journal of Molecular Sciences, 19(5), 1538. doi:10.3390/ijms1905153 ⇌ 1. What type(s) of muscle (skeletal, smooth, or cardiac) does each of the following describe? (Note: Circle the correct response(s) next to each item.) 2. Which zone or band in the sarcomere does NOT change its length during muscle contraction? Why? 3. What are the events that initiate muscle contraction, in order? Start with neurotransmitter release and trace the pathway to the point where myosin binds with actin. 4. What role does the binding of ATP to the myosin head play in the cross-bridge cycle? What about the dissociation of ADP and inorganic phosphate from the myosin head? Binding of ATP: Dissociation of ADP and inorganic phosphate: 5. What is tetanus (the physiological phenomenon, not the disease)? 1. What is the difference between compact and spongy bone? Compact bone: Spongy bone: 2. What are the three structural parts of a bone? Which part contributes most to linear growth? 3. What chemical forms most of the inorganic component of bone? 4. What are the functions of osteoblasts, osteoclasts, and chondrocytes?  Osteoblast: Osteoclast: Chondrocyte: 5. What liquid provides the lubrication for movable joints? What tissue produces it? 1. What does it mean for an allele to be dominant? Recessive? Dominant: Recessive: 2. What does it mean for a genotype to be homozygous? Heterozygous? Hemizygous? Homozygous: Heterozygous: Hemizygous: 3. What is the difference between complete dominance, codominance, and incomplete dominance?  Complete dominance: Codominance: Incomplete dominance: 4. What is the difference between penetrance and expressivity? Penetrance: Expressivity: 5. With which phase of meiosis does each of Mendel’s laws most closely correlate? Mendel’s first law: Mendel’s second law: 1. What are the three main types of point mutations? What change occurs in each? 2. What are the two main types of frameshift mutations? 3. What are the three main types of chromosomal mutations that do NOT share their name with a type of frameshift mutation? What change occurs in each? 4. Why would genetic leakage in animals be rare prior to the last century? 5. Why is genetic drift more common in small populations? What relationship does this have to the founder effect? θ 1. For each of the crosses below, what is the phenotypic ratio seen in the offspring? 2. If genes Q and R have a recombination frequency of 2%, genes R and S have a recombination frequency of 6%, genes S and T have a recombination frequency of 23%, and genes Q and T have a recombination frequency of 19%, then what is the order of these four genes in the chromosome? 3. All five criteria of the Hardy–Weinberg principle are required to imply what characteristic of the study population? 1. What are the key tenets of each of the following theories of evolution? Natural selection: Modern synthesis model: Inclusive fitness: Punctuated equilibrium: 2. What are the three patterns of selection? What changes would each create to the population phenotype? 3. What are the three patterns of evolution between species? What is the outcome of each one? 4. What is the biological definition of a species? Adapted from Gonçalves, P., Valério, E., Correia, C., de Almeida, J. M., & Sampaio, J. P. (2011). Evidence for divergent ev temperature preference in sympatric Saccharomyces species. PloS One, 6(6), e20739. θ α α β