Essential Concepts Review

Question 1

Homeostasis

Answer 1

The maintenance of a relatively stable internal environments

Question 2

Factors homeostatically regulated include :

Answer 2

• concentration of nutrient molecules
• concentration of water, salt, and other electrolytes
• concentration of waste products
• partial pressure of gases:
• o2 = 100mmHg
• CO2 = 40mmHg
• pH = 7.35-7.45
• Blood volume = 4-6 liters
• Blood pressure = 120/80 mmHg
• Temperature = 37c

Question 3

Components of a Negative Feedback system

Answer 3

Negative feedback loops consist of

• stimulus - a change
• Receptor - structures that monitor a controlled condition and detect the change
• Afferent pathway- the means to communicate information about the change from the receptor to the control center; can be neurons or blood.
• Control center (integration center) -determines the action
• Efferent - the organ or tissue that receives directions from the control center and produces
• Response - the output that removes the original stimulus

Question 4

Components of a positive feedback system

Answer 4

All the steps are same as they negative feedback “except response “

For “response” , the output that increases the original stimulus

Question 5

What’s a good example for negative feedback loop ?

Answer 5

Question 6

What’s a good example of a positive feedback loop ?

Answer 6

Question 7

Diffusion

Answer 7

The net movement of a substance from an area of high concentration to an area of low concentration; down its concentration gradient

Question 8

Permeability of the lipid bilayer

Answer 8

Question 9

Osmosis

Answer 9

The diffusion of water across a semi -permeable membrane from an area of low solute concentration to an area of high solute concentration

Question 10

The water wants to be where the ______________ is at

Answer 10

Party ( solutes)

Question 11

Hypertonic

Answer 11

Solutions have a relatively higher (solute). A cell placed in the solution will lose water and shrink ( crenate)

Question 12

Hypotonic

Answer 12

Solutions have a relatively lower ( solute). A cell placed in the solution will gain water, swell , and burst ( lyse). 

Question 13

Isotonic

Answer 13

Solutions have equal (solute). A cell placed in the solution will not change in size

Question 14

Draw the flowchart of they sodium/ potassium pump

Question 15

The sodium potassium pump

Answer 15

• most important membrane pump in all animal cells
• transport 3 Na+ out of the cells and 2 k+ into the cells for each ATP consumed
• properly called Na+/K+ ATpase

Question 16

CAMP Second messenger G protein signaling pathway

Answer 16

1. Signal molecule binds to surface receptor
2. Surface receptor activates a G protein
3. G protein activates the membrane-bound enzyme, adenylyl cyclase
4. Adenylyl cyclase catalyzes synthesis of CAMP, which binds to a protein kinase
5. Target protein initiates cellular change

Question 17

Calcium and IP3 in signaling pathways

Answer 17

Question 18