The volume of cells eliminated in healthy adult humans via programmed apoptosis is ________ ?
Show answer Hide answer
Answer: B. 50 to 70 billion cells
Explanation
Programmed cell death, or apoptosis, is a regulated process that removes damaged or unneeded cells safely. In a healthy adult human, billions of cells undergo this controlled turnover daily to maintain tissue homeostasis. Scientific estimates consistently place this routine cellular elimination between 50 to 70 billion cells per day. Apoptosis involves caspase enzyme activation that systematically disassembles cellular components without causing inflammation. This process balances cellular proliferation to keep organ sizes stable in adult human tissues. Phagocytic cells quickly engulf and clear apoptotic bodies before any leakage of intracellular contents occurs.
Defects in apoptotic pathways can lead to runaway cell survival, resulting in the formation of cancerous tumors. Conversely, excessive apoptosis contributes to neurodegenerative disorders like Alzheimer's and Parkinson's disease. Understanding programmed cell death helps researchers design therapies that trigger cancer cell self-destruction. 20 to 35 billion cells underestimates the high daily rate of natural apoptotic turnover in human adults. 10 to 20 billion cells is far too low compared to established physiological cell replacement estimates. 15 to 25 billion cells fails to reflect the extensive daily cellular recycling occurring in adult tissues.
Related questions
Q1. What is the inherent biochemical nature of nuclein?
Show answer Hide answer
Answer: B. Acidic
Friedrich Miescher extracted a phosphorus-rich substance from cell nuclei that he originally named nuclein. Subsequent chemical analysis demonstrated that this nucleic material exhibits weakly acidic properties. The acid...
Q2. The standard action potential spike of a neuronal cell measures ___________?
Show answer Hide answer
Answer: A. plus 50 mv
During an action potential, voltage-gated sodium channels open rapidly to allow a massive influx of sodium ions. This inward positive charge depolarizes the membrane and overshoots zero to reach a peak around plus 50 mV....
Q3. What is the total number of chromosomes contained within an E. coli cell?
Show answer Hide answer
Answer: A. 1
A typical Escherichia coli bacterium contains a single, circular double-stranded DNA molecule. This single chromosome encodes all the essential genetic instructions required for bacterial survival and replication. Additi...
Q4. The count of respiratory spiracles located in the thoracic segments of a cockroach is___________?
Show answer Hide answer
Answer: D. 4
Cockroaches breathe through a network of tracheal tubes connected to external openings known as spiracles. Their total respiratory system features ten pairs of spiracles distributed across thoracic and abdominal segments...
Q5. The total number of cranial nerve pairs in humans is__________?
Show answer Hide answer
Answer: C. 12
The human peripheral nervous system includes twelve distinct pairs of cranial nerves emerging from the brain. These nerves transmit sensory and motor information directly between the brain and head, neck, and organs. Eac...
Q6. A persistent notochord throughout the entire life cycle is found in___________?
Show answer Hide answer
Answer: B. Cephalochordates
Cephalochordates, commonly represented by lancelets, possess a persistent notochord throughout all life stages. This flexible rod extends the entire length of the body from head to tail without ever being replaced. Retai...