2010 physiology midterm

Question 1

A Solute is transported across the cell membrane without external energy as the concentration of this solute reaches a critical level, the concentration of this transport is saturated. What type of transport this solute is using? 
A. Simple diffusion
B. Facilitated diffusion 
C. Primary active transport
D. secondary active transport 
E. Tertiary active transport

Answer 1

B. Facilitated diffusion

Question 2

Part of the homeostatic regulation of blood pressure is through the communication of the brain to the heart. This control is a fast, and sharply localized response. What of the following is the most appropriate communication method for this response ? 
A. Neural
B. endocrine 
C. paracrine 
D. diffusion

Answer 2

A. Neural

Question 3

Na+ outside = 130   Na+ inside= 10 
Cl- outside = 118  Cl- inside= 6 
What is the membrane potential if the membrane is permeable to both Cl-and Na+ ?
A. – 1.6
B. 1.6	
C. 97.6

Answer 3

B. 1.6

Question 4

When will Intracellular edema occur?

Answer 4

When there’s low ATPase activity

Question 5

What forms gap junction?

Answer 5

Connexons

Question 6

When cell membrane becomes more negative, what is this called ? 
A. Hyperpolarization
B. Hypopolarization 
C. Repolarization
D. Over shoot

Answer 6

A. Hyperpolarization

Question 7

A substance has a volume of 60L and 280 mOsm/L, its ICF = 40L. What is its ECF total number of solutes?

Answer 7

5600 mOsmoles

Question 8

A subject has a total solutes of 15000 mOsmoles and equivalent concentration equal to 300 mOsm/L. What is the osmolarity after infusing 300ml of 500 mOsm/L of solution intravenously?

Answer 8

301.1 ~ 301.2 mOsm/L

Question 9

What is a G-protein?

Answer 9

A protein activated by binding to GTP

Question 10

Some cell surface receptors are associated with members of Janus Kinase (JAK) tyrosine kinase family. Upon ligand binding, which event is most likely to occur?
A. Dissociation of the JAK kinase from the receptor
B. Stimulation of the 2nd messengers
C. Stimulation of cAMP response element-binding protein
D. Phosphorylation of signal transducers and activators of transcription (STAT)
E. Recruitment of co-activators

Answer 10

D. Phosphorylation of signal transducers and activators of transcription (STAT)

Question 11

What best describes the role of CREB (cAMP response element-binding protein) in the cell?
A. Serve as Chaperons
B. Act as transcription factors 
C. Acts as 2nd messenger
D. Phosphorylates protein kinase A 
E. Inhibit cAMP inducible genes

Answer 11

B. Act as transcription factors

Question 12

Epinephrine binds to its receptors on heart muscle cells and causes contraction, however, it binds to its receptors on smooth muscle cells and reduces contraction, how does the same hormone cause different effects on muscle cells?
A. Different signal transduction pathways
B. Different cell types

Answer 12

A. Different signal transduction pathways

Question 13

What is the effect of hypertonic expansion on ICF volume?

Answer 13

Decrease volume of ICF

Question 14

What protects tissues from extracellular edema?

Answer 14

Removing excess fluid via lymph

Question 15

What is the osmotic pressure for 2mM of NaCl ?

Answer 15

77.2 mmHg

Question 16

A Solution contains 1 molar NaCl, 1 molar glucose, and 1 molar of CaCl2, what is the osmolarity of this solution?

Answer 16

6 mOsm\L