Biology: Mitosis and Apoptosis

Mitosis

• Nucleolus disappears during Prophase.
• Centrosome is the structure where the assembly of microtubules of the mitotic spindle begins.
• Proteins encoded by tumor suppressor genes prevent uncontrolled cell growth.
• Statement "In prometaphase, the chromosomal material called chromatin condenses" is False.
• In G2 phase, transcription and translation of genes that encode proteins necessary for cell division occur.
• In animal cells, cytokinesis occurs through segmentation.
• In telophase, the mitotic spindle breaks down, the nucleolus reappears, and a nuclear membrane forms around the chromosomes.
• G2 is the checkpoint where complete DNA replication is verified.
• Cyclin levels rise and fall during cell cycle regulation.
• Alignment of chromosomes on the metaphase plate is an internal control signal of the M phase.

Apoptosis

• When cells do not respond to control mechanisms, they produce cancer cells.
• Apoptosis is programmed cell death.
• In necrosis, a cell bursts, spilling its contents.
• The function of the apoptosome is to activate procaspase-9.
• In the proteolytic cascade, the activation of effector caspases is due to cleavage of their prodomains.
• Growth factors stimulate cell growth.
• G1 is the phase of the cell cycle where cell growth occurs.
• During prometaphase, the nuclear envelope fragments.
• Cells that undergo apoptosis die cleanly.
• Apoptosis is mediated by an intracellular proteolytic cascade.
• p53 is considered a tumor suppressor gene.
• Necrosis is characterized by bursting and swelling.
• Two procaspases are required to form an active caspase.
• After cleavage of the prodomains, procaspases must assemble.
• The phase where an active caspase can activate many other caspases is called amplification.
• Nuclear lamina degradation can occur in a cell when a proteolytic cascade is activated.
• Procaspases must undergo cleavage and assembly to form an active caspase.