Question

Where in a prokaryotic cell does the Kreb’s cycle take place?

A)nucleus. B)cytoplasm. C)Cell membrane. D)Golgi apparatus E)mitochondria.

_______

How many ATP does glycolysis yield?

A)34 B)36-38 C)2 D)12 E) 0

_______

Hydrogen peroxide is clinically effective at what dose commonly used on humans?
A)30% B) 70% C)3% D)95% E) 10%.

Answer 1

1. The prokaryotic cells lack the mitochondria. The Krebs cycle that usually occurs in matrix of mitochondria in eukaryotes, cannot occur there in prokaryotes. Hence, it takes place in cytoplasm of prokaryotic cells. Prokaryotic cells lack a well defines nucleus, mitochondria and Golgi apparatus. The cell or plasma membrane houses the electron transport chain in prokaryotes.

Right Choice: B) Cytoplasm

2) Glycolysis is breakdown of glucose to pyruvate. It produces 4 ATP molecules and utilizes 2 ATP molecules. Hence, net ATP production in glycolysis is 2 ATP. Total yield of ATP in cellular aerobic respiration is 36-38 ATP (if NADH2=3ATP and FADH2= 2 ATP). This is 8 ATP from glycolysis, 6 ATP from acetyl CoA to pyruvate, and 24 ATP from TCA cycle via ETC. Both aerobic and anaerobic respiration undergo glycolysis. Anabolic process does not produce ATP.

Right Choice: C)2.

3) Hydrogen peroxide is used as mils antiseptic agent in clinical use. Most of these preparations use H202 at 3% concentration. 30% H2O2 is usually used for laboratory purposes and can irritate the eyes, mucous membranes and skin. 95% H202 is nearly pure hydrogen peroxide. 70 and 95% hydrogen peroxide are used for industrial purposes such as rocket fuels. Cosmetic grade hydrogen peroxide is usually 3 to 10%. However, for most clinical purposes, hydrogen peroxide used is 3% as it does not cause injury to organs and cells. In clinical practice, it is used to treat cold, sinus infections, dissolve calcium and cholesterol deposits, increase oxygen content in tissues. 3% H2O2 does not usually harm human cells.

Right Choice: C) 3%