در حال بارگذاری…
MCAT biology content in question-and-answer form: cell and molecular biology, genetics, evolution, microbiology and every organ system, from nervous and endocrine to renal and reproductive. Pairs with MCAT High-Yield for the other sections.
۱۲ کارت اول از ۱۴۵ — رو و پشت هر کارت
Prokaryote vs eukaryote: key differences?
Prokaryotes: no nucleus or membrane-bound organelles, circular chromosome, 70S ribosomes. Eukaryotes: nucleus, organelles, linear chromosomes, 80S ribosomes
Function of the rough ER?
Synthesis of proteins destined for secretion, the cell membrane or lysosomes
Function of the smooth ER?
Lipid synthesis and detoxification (also Ca²⁺ storage in muscle as sarcoplasmic reticulum)
Function of the Golgi apparatus?
Modifies (e.g., glycosylation), sorts and packages proteins into vesicles
Function of lysosomes?
Digest material with acid hydrolases at low pH (~4.5–5)
Function of peroxisomes?
Break down very-long-chain fatty acids via β-oxidation; produce and degrade H₂O₂
Evidence that mitochondria were once bacteria?
Own circular DNA, 70S-like ribosomes, double membrane, divide by binary fission (endosymbiotic theory)
Microfilaments, microtubules, intermediate filaments: made of what?
Microfilaments: actin. Microtubules: tubulin. Intermediate filaments: e.g., keratin, vimentin, lamins
Roles of microtubules?
Cell shape, intracellular transport (kinesin, dynein), mitotic spindle, cilia and flagella (9+2 arrangement)
Tight junctions vs desmosomes vs gap junctions?
Tight: seal paracellular space. Desmosomes: anchor cells (intermediate filaments). Gap: channels for ions/small molecules between cells
Fluid mosaic model?
Phospholipid bilayer with embedded, laterally mobile proteins; cholesterol modulates fluidity
Passive vs active transport?
Passive (simple/facilitated diffusion, osmosis): down a gradient, no energy. Active: against a gradient, uses ATP (primary) or another gradient (secondary)