Why is it correct to call red blood cells living cells?
Answer:
Because they fulfill all other characteristics of life except reproduction
Explanation:
I don’t know if my explanation will be fit for sieve plate, but I’ll be answering based on my knowledge about Red Blood cells (erythrocytes).
Now the characteristics of life are:
1. Cellular Organization : Since we are considering a single cell, cellular organization doesn’t matter.
2. Reproduction: Precursors of Red Blood cells are initially produced in the bone marrow with a nucleus which are capable of reproduction. After attaining maturity, there nucleus is removed for functional reasons (to increase space and decrease energy usage). Important thing to not is that many fully differentiated cells can’t replicate. For example, neurons or mammalian RBCs
3. Metabolism: RBCs produce energy by anaerobic glycolysis to maintain its metabolic functions
4. Homeostasis: RBCs maintain nearly constant conditions in the internal environment
5. Heredity: Since matured RBCs don’t have a nucleus, they cannot reproduce. But the precursors of RBCs (Hematopoietic stem cells) does have nucleus and is capable of producing new RBCs
6. Response to Stimuli: RBCs respond to stimuli
7. Growth and Development: RBCs originate from hematopoietic stem cells and grow to a fully mature erythrocyte
8. Adaptation through Evolution: Removal of nucleus was infact an evolution of the RBCs which is only seen in mammals (birds or amphibians for example have nucleated RBCs)
Since RBCs fulfill most of the characters of life and has a way to continue their existance even though not being able to reproduce in the conventional sense, they can in fact be called living cells despite their lack of nucleas (in matured state).