Ch 3: Cellular Form and Function

Question 1

nucleus

Answer 1

surrounded by double membrane with pores; contains fluid (nucleoplasm); known as the “control center” (DNA); and participates in protein synthesis (mRNA)

Question 2

nucleolus

Answer 2

located in nucleoplasm; r RNA synthesis

Question 3

mitochondria

Answer 3

“powerhouse” (ATP); oval shape with outer membrane; middle membrane; and inner membrane (cristae); contains fluid (matrix)

Question 4

ribosomes

Answer 4

protein synthesis; two types – free (cytoplasm; make protein for that cell); bound (attached to rough ER; make protein to be transported out)

Question 5

endoplasmic reticulum

Answer 5

two types – Rough (transport proteins); Smooth (transport lipids); both have series of membranous channels called cisternae; rough ER has bound ribosomes attached to cisternae

Question 6

golgi apparatus

Answer 6

series of saccules and vesicles (motile); storage and secretion; modify proteins)

Question 7

lysosomes

Answer 7

contain digestive enzymes (remove damaged organelles; digest nutrients; and remove foreign substances)

Question 8

peroxisomes

Answer 8

type of lysosome; neutralize hydrogen peroxide

Question 9

cytoskeleton

Answer 9

gives support and shape to the cell; also movement of organelles; made up of microfilaments, intermediate filaments, and microtubules

Question 10

cell structure (cytoplasm)

Answer 10

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

Question 11

bilayer of phospholipids

Answer 11

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

Question 12

proteins

Answer 12

integral (pores); and peripheral (to each side of membrane; give support)

Question 13

cholesterol

Answer 13

hydrophobic; regulate the amount of water that enters & exits the cell

Question 14

glycocalyx

Answer 14

at surface; glycoproteins and glycolipids; surface marker; helps immune system recognize self and non-self cells

Question 15

receptors

Answer 15

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)

Question 16

second messenger systems

Answer 16

when a first messenger binds to a surface receptor, it may trigger changes within the cell that produce a second messenger in the cytoplasm;

Question 17

List the process in the second messenger mechanism

Answer 17

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

Question 18

enzymes

Answer 18

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

Question 19

passive transport

Answer 19

movement across cell membrane from higher gradient to lower gradient; no ATP; 4 types

Question 20

What are the 4 types of passive transport

Answer 20

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).

Question 21

active transport

Answer 21

movement across cell membrane from lower gradient to higher gradient; ATP; 3 types

Question 22

what are the 3 types of active transport

Answer 22

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