Question

Are the following statements true or false?

1. Lipofuscin may accumulate in old cells.

2. Proteasomes are cellular "garbage cans"

3. Ubiquitin marks proteins for degradation in proteasomes.

4. LDLs and HDLs transport cholesterol.

5. Late endosomes belong to the endocytic pathway.

6. Proteins destined for mitochndria are synthesized on free ribosomes.

7. Brownian ratchet is a type of biased diffusion.

8. Cholesterol is internalized by RME.

Answer 1

1. Lipofuscin may accumulate in old cells. ----> TRUE (The active process of aging includes the appearance of new substances. For example the cellular degradation results in the accumulation of lipofuscin granules. )

2. Proteasomes are cellular "garbage cans" ----> FALSE (Lysosomes are the cellular "garbage cans")

3. Ubiquitin marks proteins for degradation in proteasomes. ----> TRUE

4. LDLs and HDLs transport cholesterol. ----> TRUE (LDLs transport cholesterol from the liver to tissues; while the HDLs transport cholesterol from the tissues to liver)