Histology Certification Cellular Structures 3

Question 1

In electron microscopy, the smooth endoplasmic reticulum (SER) is distinguished from the rough endoplasmic reticulum (RER) by the absence of:

Accepted Answer

Ribosomes on its cytoplasmic surface

Answer

The RER bears ribosomes on its cytoplasmic face giving it a 'rough' appearance in EM, whereas the SER lacks ribosomes and appears smooth.

Question 2

Peroxisomes detoxify harmful substances and are particularly abundant in hepatocytes. Their key enzyme for hydrogen peroxide decomposition is:

Accepted Answer

Catalase

Answer

Catalase converts the H₂O₂ generated by peroxisomal oxidases into water and oxygen, preventing oxidative cellular damage.

Question 3

The centrosome, which serves as the main microtubule-organizing center in animal cells, consists of:

Accepted Answer

Two centrioles surrounded by pericentriolar material

Answer

The centrosome contains two centrioles (a mother and daughter) embedded within pericentriolar material (PCM) that nucleates microtubule polymerization.

Question 4

Which microscopic finding best indicates active apoptosis in a histological section?

Accepted Answer

Cellular and nuclear fragmentation into membrane-bound apoptotic bodies

Answer

Apoptosis produces condensed chromatin, nuclear fragmentation (karyorrhexis), and blebbing of the membrane to form apoptotic bodies, without eliciting inflammation.

Question 5

The glycocalyx coating the luminal surface of endothelial cells is composed primarily of:

Accepted Answer

Proteoglycans and glycoproteins

Answer

The glycocalyx is a carbohydrate-rich layer formed by proteoglycans, glycoproteins, and glycolipids anchored to the plasma membrane, mediating cell–cell and cell–matrix interactions.

Histology Certification Practice Test

Histology Certification Practice Test

Histology Certification Cellular Structures 3