Ch 3: Cellular Form and Function Flashcards
nucleus
surrounded by double membrane with pores; contains fluid (nucleoplasm); known as the “control center” (DNA); and participates in protein synthesis (mRNA)
nucleolus
located in nucleoplasm; r RNA synthesis
mitochondria
“powerhouse” (ATP); oval shape with outer membrane; middle membrane; and inner membrane (cristae); contains fluid (matrix)
ribosomes
protein synthesis; two types – free (cytoplasm; make protein for that cell); bound (attached to rough ER; make protein to be transported out)
endoplasmic reticulum
two types – Rough (transport proteins); Smooth (transport lipids); both have series of membranous channels called cisternae; rough ER has bound ribosomes attached to cisternae
golgi apparatus
series of saccules and vesicles (motile); storage and secretion; modify proteins)
lysosomes
contain digestive enzymes (remove damaged organelles; digest nutrients; and remove foreign substances)
peroxisomes
type of lysosome; neutralize hydrogen peroxide
cytoskeleton
gives support and shape to the cell; also movement of organelles; made up of microfilaments, intermediate filaments, and microtubules
cell structure (cytoplasm)
mainly composed of water; contains all compounds that enter or are made by the cell; contains the organelles (except nucleolus); all chemical reactions occur in the cytoplasm
bilayer of phospholipids
polar heads (hydrophilic); non-polar tails (hydrophobic); heads point to surface and interior of cell; tails make up middle of membrane; regulate the amount of water that enters & exits the cell
proteins
integral (pores); and peripheral (to each side of membrane; give support)
cholesterol
hydrophobic; regulate the amount of water that enters & exits the cell
glycocalyx
at surface; glycoproteins and glycolipids; surface marker; helps immune system recognize self and non-self cells
receptors
many chemical signals by which cells communicate cannot enter the target cell but bind to surface proteins called receptors; usually specific for one particular messenger; chemical signal is usually a hormone (i.e. epinephrine)
second messenger systems
when a first messenger binds to a surface receptor, it may trigger changes within the cell that produce a second messenger in the cytoplasm;
List the process in the second messenger mechanism
a first messenger (epinephrine) binds to a receptor in the cell membrane
the receptor releases a G protein, which then travels freely in the cytoplasm
the G protein binds to an enzyme (adenylate cyclase) located in the cell membrane; adenylate cyclase converts ATP to cyclic AMP (cAMP) which is the second messenger
cAMP activates a cytoplasmic enzyme (kinase)
kinases add phosphate groups (Pi) to other cytoplasmic enzymes; can activate or deactivate some enzymes which leads to various metabolic effects in the cell
enzymes
carry out the final stages of starch and protein digestion in the small intestine; help produce second messengers; and break down hormones and other signaling molecules when the job is done, to prevent excessively stimulating the cell
passive transport
movement across cell membrane from higher gradient to lower gradient; no ATP; 4 types
What are the 4 types of passive transport
Simple Diffusion (Diffusion) – movement of solutes from higher conc. to lower conc.; no ATP; Gas Exchange
Facilitated Diffusion – movement of solutes from higher conc. To lower conc.; with use of carrier molecule; no ATP; insulin transporting glucose into cell
Filtration – movement of solutes from higher pressure to lower pressure; no ATP; first step in urine formation
Osmosis – movement of solvent (water) from higher water conc. to lower water conc.; no ATP; hypertonic (saturated) solution – water exits cell (dehydration; crenation of RBC); hypotonic (dilute) solution – water enters cell (swell / burst; hemolysis of RBC); isotonic (equilibrium) solution – no movement of water (cell appears normal).
active transport
movement across cell membrane from lower gradient to higher gradient; ATP; 3 types
what are the 3 types of active transport
Phagocytosis – “cell eating”; cell engulfs particles; cell is motile; requires ATP; certain White Blood Cells (macrophages)
Pinocytosis – “ cell drinking”; cell forms vesicles to take in fluids and nutrients; requires ATP; all cells
Sodium/Potassium Pump – cell pumps out 3 sodiums and pumps in 2 potassiums; requires ATP; all cells; also muscle cells & nerve cells