Introduction to Physiology and Cell Physiology

What is the volume of the ECF of a patient who weighs 77 kg?

• 15.4 L

• 46.2 L

• 30.8 L

• 11.5 L

Answer explanation

ECF = 0.2 X Body Weight

0.2 X 77 = 15.4 L

Fluid surrounding the cells in the muscle tissue comprise which compartment in the body?

• Intracellular fluid

• Plasma

• Interstitial fluid

• Extracellular fluid

The following ions are abundant in the intracellular fluid compartment except

• Potassium

• Bicarbonate

• Magnesium

• Phosphate

Answer explanation

ECF contains NA, Cl, HCO3

ICF contains large amounts of K, Mg, PO4

Central chemoreceptors regulate respiration by sensing changes in the concentration of which ion?

• Hydrogen ions

• Bicarbonate ions

• Hydroxide ions

• Carbon monoxide

Answer explanation

Central chemoreceptors regulate respiration by sensing changes in pH

Which of the following statements are correct about peripheral proteins in the cell membrane

• Span the entire lipid bilayer

• Can function as pores

• Can serve as carrier proteins

• Can help regulate the transport of substances through the pores

Answer explanation

Peripheral proteins do not span the entire lipid bilayer and therefore cannot function as pores or as carrier proteins. They can, however, regulate the transport of substances through pores (e.g. in gated pores)

The following statements are true of the membrane flow model for amoeboid movement except

• Endocytic vesicles are made from the middle and rear portions of the cell

• The rear edge anchors the cell to the surrounding tissue

• Actin and myosin fibers transport the endocytic vesicles to the pseudopodial end

• New plasma membrane is continuously formed, causing the cell to move forward

Answer explanation

It is the leading edge or the pseudopodial end that anchors the cell to the surrounding tissue

Zellweger syndrome is a peroxisome disorder characterized by craniofacial dimorphism and severe neurologic abnormalities. Increased plasma VLCFA (very long chain fatty acid) concentrations are seen due to errors in its metabolism. Which step in fatty acid metabolism happens in peroxisomes?

• Beta oxidation

• Carboxylation

• Reduction

• Dehydration

Answer explanation

Peroxisome contains peroxidases. Some of these peroxidases are also responsible for fatty acid oxidation

The following statements are true regarding mitochondria except

• The cristae increases the surface area for oxidative phosphorylation to occur

• The intermembrane space has high hydrogen ion concentrations

• the Krebs cycle occurs within the mitochondrial matrix

• ATP synthase is located in the outer membrane

Answer explanation

ATP synthase is located in the membrane of the cristae

What is the function of DNA ligase in DNA synthesis?

• Unzips the DNA double helix

• Joins together the Okazaki fragments

• Supercoils the DNA

• Proofreads DNA synthesis

Answer explanation

Helicase unzips the DNA double helix

Topoisomerase III or reverse DNA gyrase supercoils the DNA

pol I and pol II are involved in proofreading DNA synthesis

Mitotic catastrophe can happen when there is failure to pull the two sister chromatids apart towards the opposite poles during cell division. What phase in mitosis can show this failure?

• Prophase

• Metaphase

• Anaphase

• Telophase