dat bio question

[deebs]

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okay so I'm studying for the DAT and I'm having a pretty difficult time discerning whether or not germ cells undergo both mitosis or meiosis. I've always been lead to believe that germ cells (sex cells) only undergo meiosis and only somatic cells undergo mitosis.

However, looking at spermatogenesis, a spermatogonia undergoes mitosis in order to produce a primary spermatocyte (which later undergoes meiosis I to produce secondary spermatocyte then again meiosis II to produce spermatid which mature to produce spermatozoa) Doesn't this show that sex cells actually do undergo mitosis at some point in order to replenish and also meiosis to produce haploid sex cells?

this may be overdoing it for the DAT but I'm really curious to know the answer now... 😀

 

[phy241]

Hey, only male germ cells (spermatogonia) undergo mitosis, and this is why males stay fertile forever. Before the spermatogonia is about to undergo meiosis in Sertoli cells, it undergoes mitosis so one daughter cell goes through the process of forming spermatids whereas the other one stays and keeps the # of primary germ cells constant. On the other hand, females have a limited number of germ cells or oogonia (I believe around 1-2 million at birth), and they do not undergo mitosis, which is why the germ cell reserve decreases as they age.
So to answer your question, only male germ cells undergo mitosis not females, but ALL germ cells undergo meiosis (unequal cytokinesis in females). Hope this helps!

okay so I'm studying for the DAT and I'm having a pretty difficult time discerning whether or not germ cells undergo both mitosis or meiosis. I've always been lead to believe that germ cells (sex cells) only undergo meiosis and only somatic cells undergo mitosis.

However, looking at spermatogenesis, a spermatogonia undergoes mitosis in order to produce a primary spermatocyte (which later undergoes meiosis I to produce secondary spermatocyte then again meiosis II to produce spermatid which mature to produce spermatozoa) Doesn't this show that sex cells actually do undergo mitosis at some point in order to replenish and also meiosis to produce haploid sex cells?

this may be overdoing it for the DAT but I'm really curious to know the answer now... 😀

 

[deebs]

thanks! Hypothetically, what if we were asked what germ cells undergo, would you answer mitosis, meiosis or both? Would that even be posed as a question on the DAT?

 

[phy241]

If it says, what do ALL germ cells undergo, then I would pick meiosis only. If it says, which one of these processes can germ cells undergo, then I would pick both. However, it's very ambiguous, I highly doubt they would ask something like that, but it's very important to know the difference between oogenesis and spermatogenesis, so make sure you know those well.

thanks! Hypothetically, what if we were asked what germ cells undergo, would you answer mitosis, meiosis or both? Would that even be posed as a question on the DAT?