Answer:
All of these choices are correct.
Explanation:
Cell cycle is the process of growth and division of cell. It comprises of interphase and mitosis. In interphase the cell grows, replicates its genomic content and prepares itself for division. In mitosis the division occurs.
Cell cycle is controlled by a group of kinases called as Cyclin dependent Kinases (CDKs). They act by phosphorylating their substrates. They are of various types like Cdk1, Cdk2, Cdk4 etc. They become active when they bind to a regulatory protein called cyclin. They are also of various types like Cyclin A, Cyclin B, Cyclin C etc. Level of cyclin and corresponding CDK increases and decreases according to the stage of cell cycle. For example in S phase of cell cycle concentration of cyclin A and E shoots up. CDK2 is able to bind to these cyclin molecules and hence it becomes active.
Cell cycle has major checkpoints where the condition of cell is analysed before it proceeds to the next stage of cycle. If any abnormality is detected, repair mechanism is activated or the cell is killed. Checkpoints do not allow cell cycle to proceed in damaged cells.
p53 is a tumor suppressor protein which can halt cell cycle when it detects some abnormality in cell. It usually acts in G1/S checkpoint (before the DNA replication starts in cell) and G2/M checkpoint (before the cell division begins). Hence, all of the above statements are true.
Answer: Yes, Endocytosis and exocytosis can occur in the same cell. It is how a cell transport and export material in and out.
Explanation: Hope this helps :) and amazing question btw
Answer: False
Explanation:
Conventionally pasteurized milk is not sterile it gets sterile after it is homogenized. The process of pasteurization involves sudden heating and sudden cowling of milk which does not kills all the microorganism but is intended to kill some of the bacteria and inactivates some enzyme.
Homogenization is a completely separate process which involve mechanical breakdown of fat molecules in the milk which increases the shelf life of milk by preventing the cream from rising at the top.
Hence, the given statement is False.
True. Alluvial fans, deltas, and deposition are examples of land formations that are formed from deposits by rivers.
Answer:
B New cells come from preexisting cells.
