Mitosis / Meiosis - Haploid Diploid

[matth87]

Mitosis can occur in diploid and haploid cells

Meiosis can occur only in diploid cells.

Are these true statements? I know the second half of meiosis occurs in a haploid cell but TPR science workbook messed me up on this question.

Also does Mitochondrial and Chloroplast DNA replicate in G1 of the cell cycle?

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[RogueUnicorn]

mitochondria and chloroplast, if i know this correctly, divide independently. while they are dependent on certain cell signals, i don't think it's all that important for the purposes of the mcat.. hopefully a more bio-inclined person can chime in.

meiosis only occurs in diploid cells under normal conditions.

 

[Hemichordate]

Are bacteria only capable of binary fission, or mitosis as well?

 

[matth87]

Are bacteria only capable of binary fission, or mitosis as well?

Only binary fission since they have one circular DNA chromosome. They can also have tiny circular chromosomes, plasmids too. They don't under go mitosis.

Binary fission produces "exact" replicas with zero genetic variation. Only way they can vary their genomes is through conjugations with each other, transformation from the environment, transduction from viruses, or mutations.

 

[RogueUnicorn]

Are bacteria only capable of binary fission, or mitosis as well?

mitosis/meiosis requires centrosomes/centrioles, which are now thought to have arisen out of endosymbiosis, i think. regardless, bacteria do not undergo mitosis.