MCAT Biology Review Lecture Notes

Introduction

• Overview of biology section for the MCAT using Milestone review sheets.
• Achieved 100th percentile using these methods, believes all necessary information is covered.

Cell Structure

Prokaryotic Cells

• Nucleoid: DNA region, no nucleus.
• Ribosomes: Present in both prokaryotes and eukaryotes, essential for protein synthesis.

Eukaryotic Cells

• Nucleus: Contains nucleolus for making ribosomes.
• Peroxisomes: Break down harmful substances.
• Golgi Apparatus: Modifies and distributes proteins.
• Centrioles and Centrosomes: Involved in cell division.

Bacteria

• Shapes: Bacilli (rods), cocci (spheres), spiral.
• Oxygen Requirements: Obligate aerobes (require O2), obligate anaerobes (die in O2), facultative anaerobes (can switch), aerotolerant anaerobes (tolerate O2).
• Gram Stain: Gram-positive (thick peptidoglycan, purple), Gram-negative (thin peptidoglycan, pink, with outer membrane).

Eukaryotes vs. Prokaryotes

• Eukaryotes: ETC in mitochondria, large ribosomes, mitosis.
• Prokaryotes: ETC in cell membrane, small ribosomes, binary fission.

Genetics and Microbiology

• Transformation, Conjugation, Transduction: Methods of genetic recombination in bacteria.
• Viruses: Structure, retroviruses, bacteriophages.

Cell Cycle and Mitosis

• Phases: G1 (cell growth), S (DNA replication), G2 (prep for mitosis), M (mitosis), Cytokinesis.
• Control: Cyclins, CDKs, p53.

Meiosis

• Phases: Similar to mitosis but with genetic diversity through crossing over.
• Non-disjunction: Leads to aneuploidy (e.g., Down syndrome).

Reproductive Systems

Male

• Pathway: Seminiferous tubules, epididymis, vas deferens, ejaculatory duct, urethra.
• Glands: Prostate (alkaline fluid), seminal vesicles.

Female

• Ovaries and Uterus: Ovulation cycle, role of estrogen and progesterone.
• Hormones: FSH, LH, GnRH.

Embryogenesis

• Fertilization to Gastrulation: Stages of early development.
• Germ Layers: Ectoderm (attracto-derm), mesoderm (movement), endoderm (internal organs).

Nervous System

• Neuron Types: Afferent, efferent, interneurons.
• Action Potential: Depolarization and repolarization phases.
• Neurotransmitters: Synapse functions, removal methods.

Endocrine System

• Hormones: Peptide and steroid differences, hormone pathways.
• Glands: Hypothalamus, pituitary, thyroid, adrenal cortex.

Respiratory System

• Pathway: Nose to alveoli, gas exchange.
• Lung Function: Spirometry, breathing mechanisms.

Cardiovascular System

• Heart Structure and Function: Blood flow path, cardiac cycle.
• Blood Pressure: Control mechanisms, cardiac output.

Immune System

• Innate vs. Adaptive Immunity: Key components and cells involved.
• Lymphatic System: Role in fluid balance and immune response.

Digestive System

• Pathway: From oral cavity to intestines.
• Enzymes and Hormones: Digestive functions and regulations.

Excretory System

• Kidney Function: Filtration, reabsorption, secretion.
• Nephron Structure: Functional unit of the kidney.

Skin

• Structure: Layers of skin and their functions.
• Thermoregulation: Processes for heat control.

Musculoskeletal System

• Muscle Types: Skeletal, smooth, cardiac.
• Bone Structure: Types, cells, and remodeling.

Genetics and Evolution

• Genetic Variation: Alleles, genotypes, phenotypes.
• Natural Selection and Evolution: Mechanisms and types.

These notes cover the key points from the biology section of the MCAT as explained in the provided transcript. Be sure to review each section thoroughly for understanding.