Chapter 3 Flashcards
What is a prokaryotic cell?
a single-celled organism that lacks a nucleus and other membrane-bound organelles.
What is a eukaryotic cell?
organisms whose cells have a nucleus enclosed within a nuclear envelope
What are the four main functions of cells?
cell metabolism and energy use
synthesis of molecules
communication: chemical messages
reproduction and inheritance
What is CRISPR?
gene editing, cutting DNA at a certain location
What does selectively permeable mean?
a membrane that allows the free passage of some molecules, but restricts others
What can cross a membrane without help?
hydrophobic (non-charged) molecules
small uncharged molecules (H2O, indole)
large uncharged molecules (glucose, sucrose)
Ions (Cl-, K+, Na+)
What is simple diffusion?
molecular movement of solutes (small inorganic ions; lipid-soluble materials)
What is osmosis?
Movement of water molecules toward solution containing relatively higher solute concentration
selectively permeable membrane
WATER ONLY
What is facilitated diffusion?
carrier proteins passively transport solutes across a membrane down a concentration gradient
polar; small
glucose and amino acids (hydrophilic)
What is active transport?
carrier proteins actively transport solutes across a membrane. against the concentration gradient
ATP
Na+, K+, Ca2+, Mg2+
What is secondary active transport?
carrier proteins actively transport two solutes, with one (Na+) moving down its concentration gradient; then expends ATP to eject the Na+
ATP
glucose and amino acids; iodide
What is endocytosis?
Crenation of membranous vesicles containing fluid or solid material
ATP
fluid, nutrients, debris, pathogens
What is exocytosis?
fusion of vesicles containing fluids or solids (or both) with the plasma membrane;
ATP
fluid, debris
What is hypotonic?
The solution with the lower osmolarity
What is hypertonic?
the solution with the higher osmolarity
