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) Cell organelles are randomly scattered in the cytoplasm.

2) The cytoskeleton is like the pillars of a building, it is stable through the lifespan of the cell.

3) Microtubules, actin filaments and intermediate filaments are the three components of the cytoskeleton.

4) Cytoskeleton is made up of proteins that associate to form filaments.

5) There are cytoskeleton filaments made up of actin and tubulin, others contain keratins and tubulin. That is, there are mixed filaments.

6) Actin filaments are found within the nucleus.

7) Actin filaments are involved in phagocytosis, endocytosis, and cell movements.

8) Actin filaments are polarized filaments.

9) New actin filaments are nucleated by protein complexes.

10) Actin filaments are highly dynamics because of the large set of associted proteins.

11) Cells can move because actin filaments can be stretched.

12) Muscle cell contraction is caused by Type I myosins sliding along the actin filaments.

13) During cell division, cytokinesis is driven by microtubules.

14) Microvilli are filiform cellular expansions containing a scaffold of actin filaments and found in the free surface of some epithelial cells.

15) Microtubules are made up of alpha and gamma tubulin dimers.

16) Protofilaments are rows of tubulin dimers that form the wall of the microtubule.

17) Microtubules mostly grow the plus end of the filament

18) Dynamic instability is hability of microtubules to bend and form loops.

19) GTP-tubulin dimers are formed in the cytosol from GDP-tubulin dimers.

20) MTOCS are structures where microtubules are nucleated.

21) Centrosome is the main microtubule organizing center of animal cells.

22) Plant cells contain centrosomes.

23) Tubulin dimers are responsible for the movement of cargoes along the microtubule.

24) Dyneins move toward the minus end of the microtubule

25) Cilia and flagella microtubules show dynamic instability.

26) Cilia and flagella microtubules nucleate from the centrosome.

27) The formation of the mitotic spindle is one of the functions of microtubules.

28) Intermediate filaments counteract mechanical forces in animal cells.

29) Tight junctions are connected to the intermediate filaments of the cytoplasm.

30) The integrity of the nuclear envelope depends on the intermediate filaments.

31) Proteins that form intermediate filaments consist of two globular domains in the ends separated by a linear domain.

32) Intermediate filaments can be stretched.

33) Vimentin is a type of keratin.