Unit 2

Question 1

Hydrophobic molecules

Answer 1

O2, CO2, N2, can pass thru

Question 2

Small, uncharged polar molecules

Answer 2

H2O, glycerol, can pass thru

Question 3

Large, uncharged polar molecules

Answer 3

Glucose, sucrose, need transport molecule

Question 4

Ions

Answer 4

H+, Na+, HCO3-, Ca2+, Cl, need transport molecule

Question 5

paracrine signaling

Answer 5

a signaling cell acts on nearby target cells by secreting molecules of a local regulator (ex growth factor)

Question 6

synaptic signaling

Answer 6

a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell, such as a muscle or another nerve cell

Question 7

ligand gated ion channel receptor

Answer 7

channel remains closed until ligand (signaling molecule binds to the receptor), specific ions can then flow through

Question 8

three types of signaling

Answer 8

1. ligand gated ion channel (signal binds to passive ion channel, opens it, some nerve chennels work this way) 2. steroid signal with intra-cellular receptor
2. signal transductin signal with membrane surface receptor

Question 9

cyclic AMP is made from

Answer 9

an ATP molecule by the enzyme adenylyl cyclase

Question 10

phophodiesterase

Answer 10

inactivates cAMP by converting it into inactive non-cyclic adenonsine monophosphate (AMP)

Question 11

More free energy

Answer 11

• higher G
• less stable
• more work capacity

Question 12

Less free energy

Answer 12

• smaller G
• more stable
• less work capacity