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) One of the function of cell membranes is to form ionic gradients that are used for ATP synthesis.

2) The structure of membranes is based in the physicochemical features of membrane lipids.

3) Carbohydrates linked to membrane proteins and lipids are found at the cytosolic surface of plasma membrane.

4) All cellular membranes have the same amount of proteins and lipids.

5) Sphingolipids are the main lipid type of cell membranes.

6) Lipids influence the memebrane fluidity.

7) Cholesterol is found in the inner leaflet of the plasma membrane, but not in the external leaflet.

8) Lipids are evenly distributed in cell membranes because of the membrane fluidity.

9) Most functions of membranes are carried out by membrane proteins.

10) Transmembrane proteins are anchored to the plasma membrane by hydrophobic forces.

11) Peripherlal proteins are linked to the surface membrane by chemical bond.

12) Glycocalyx is the cloud of carbohydrates that covers the external surface of cells. These carbohydrates are linked to plasma membrane molecules.

13) Carbohydrates of plasma membrane are chemically bound to proteins and lipids.

14) Membrane carbohydrates have no specific functions.

15) Membrane semipermeability it is a membrane property that allows the lateral movement of lipids.

16) Oxygen and carbon dioxide may cross the plasma membrane without restrictions.

17) Water can freely crosses the plasma membrane.

18) Lipid rafts make possible characteristic chemical environments that favor some chemical reactions and molecular interactions.

19) Membrane asymmetry means that there is different molecular composition between both leaflet of the membrane.

20) Large membrane breakages (of about 0,2 µm) are sealed by the lipid properties.

21) Transmembrane proteins of the plasma membrane are mostly synthesized in the Golgi apparatus.

22) Transmembrane proteins of mitochondrial membranes are synthsized in the endoplasmic reticulum.

23) Cell membranes are continuously renewed.

24) Ion gradients can be created thanks to the permeability properties of membranes.

25) Pumps are membrane proteins that generate ion gradients by ATP hydrolysis.

26) Cotransport of molecules across membranes is carried out by proteins called co-transporters.

27) Canals are transmembrane proteins that allow ions to cross membranes against concentration gradient.