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:
D the current changes are mush smaller than in the past.
Answer:
cytoskeleton is a structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement
Answer:
The answer to your question is:
Explanation:
When carbon attached to oxygen, they form covalent bonds, in these kind of bonds, atoms share electrons to acquire stability.
Atoms acquire stability when they have 8 electrons in their outermost shell.
When carbon share electrons with oxygen they acquire 8 electrons and they are stable.
See the picture below
Red is carbon and blue oxygen
