Atlas of Plant and Animal Histology

Choose true or false. Each right answer scores 1, and each wrong answer scores -1. Not answered questions score 0.

1) Vesicular trafficking is the communication between membrane-bound organelles by means of vesicles.

2) The secretory pathway begins in the endoplasmic reticulum and ends in the plasma membrane.

3) Vesicular communication between membrane-bound organelles is bidirectional. It means that is organelle A sends vesicles to organelle B, B sends vesicles to A.

4) There are two types of endoplasmic reticulum: rough and smooth. They are separated organelles.

5) The endoplasmic reticulum is fisically connected with the nuclear envelope.

6) Rough endoplasmic reticulum form tubules and the smooth endoplasmic reticulum form flattened cisterns.

7) Rough endoplasmic reticulum is a main center for protein synthesis.

8) Those cells with a very large rough endoplasmic reticulum are specialized in secretion.

9) The messenger RNAs need to enter the rough endoplasmic reticulum to be translated into proteins.

10) Glycosidation takes place in the endoplasmic reticulum.

11) Proteins sinthesized in the rough endoplasmic reticulum may have errors. These proteins are selected and removed before being exported to the Golgi apparatus.

12) Proteins syntheized in the endoplasmic reticulum can be targeted to mitochondria.

13) Most lipids of the cell membranes are synthesized in the smooth endoplasmic reticulum.

14) The endoplasmic reticulum is a storage for calcium.

15) The region of the endoplasmic reticulum that releases the vesicles targeted to the Golgi apparatus is referred as exit zone.

16) Protein COP-I coats form vesicles in the endoplasmic reticulum.

17) Molecules transported by vesicles formed in the endoplasmic reticulum enter those vesicles in a random way.

18) The ERGIC compartment is originated by disintegration of the Golgi apparatus cisterns.

19) The pH in the endoplasmic reticulum is lower, i.e., more acid, than in the Golgi apparatus.

20) The Golgi apparatus is found in different cytoplasmic regions when comparing animal and plant cells.

21) The Golgi apparatus is a polarized organelle.

22) The Golgi apparatus consists of many tubular ducts connected to one another in a widespread network.

23) The cistern maturation model of the Golgi apparatus for the travel of molecules from the cis domain to the trans domain gets more support than other models.

24) The Golgi apparatus is a major glycosidation center of the cell.

25) The Golgi apparatus is involved in both exocytosis and endocytosis pathways.

26) Exocytosis is the fusion of vesicles with the plasma membrana.

27) Constitutive exocytosis requires an increase in the cytosolic concentration of calcium.

28) All cellular types perform regulated exocytosis.

29) All vesicles that fuse with plasma membrane are generated in the trans domain of the Golgi apparatus.

30) Endocytosis is a process to incorporate molecules enclosed in vesicles into the cell.

31) Molecules that enter the cell by pinocytosis must be specifically recognized.

32) Only extracellular molecules are incorporated during edocytosis.

33) Receptor mediated endocytosis is a way to specifically select and import some molecules, enclosed in vesicles, into the cell.

34) Clathrin is a transmembrane protein involved in the formation of caveolae.

35) Endocytic vesicles can be formed without clathrin and caveolin.

36) Macropinocytosis is a type of phagocytosis.

37) Early endosomes are membrane-bound compartments that can send vesicles targeted to the plasma membrane.

38) Vesicles coming from several cell compartments can fuse with endosomes.

39) Some authors suggest that there is no vesicular trafficking between different endosomes.

40) Molecules imported by receptor mediated endocytocis are released in the early endosomes by a decrease of pH in this compartment.

41) Multicesicular bodies are formed from the fusion of cytosolic vesicles.

42) Vesicles from the endoplasmic reticulum are targeted to the late endosomes.

43) Transcytosis is the vesicular communication between late endosomes and lysosomes.

44) Lysosomes are organelles to degrade molecules coming from endocytosis, phagocytosis and macropinocytosis.

45) Lysosomal enzymes dregrade a wide variety of molecules.

46) Lysosomal enzymes may degrade the cytoplasm if they scape from lysosomes.

47) Molecules to be degraded in lysosomes are only coming from endocytosis.

48) Lysosomes can fuse with the plasma membrane.

49) Vacuoles are important organelles for plant cells.

50) The vesicular trafficking in plant cells shows communication pathways not found in animal cells.

51) Endocytosis is a prominent part of the plant cell vesicular trafficking.

52) Vacuoles are typical organelles of animal cells.

53) Plasmalemma is the name of the vacuole membrane.

54) Vacuoles are usually small organelles.

55) A major function of vacuoles is to generate cell turgor pressure.

56) Vacules may store molecules.

57) Vacuoles may degrade molecules, as lysosomes of animal cells do.