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What are the roles of mitosis and meiosis in a eukaryotic life cycle?
Wiki User
∙ 15y ago
Mitosis results in growth. During mitosis a cell becomes two. Genetically, the two daughter-cells are identical to each other and to the original cell. In single-celled organisms the daughter-cells separate. But in multicellular species the cells remain together. Mitosis therefore increases the number of cells in a multicellular organism. This makes differentiation possible. In humans, for example, some cells become blood cells, some muscle tissue, some light receptors at the back of the eye, and so on. Meiosis halves the chromosome number. In the course of meiosis a cell divides once, half its chromosomes going into each daughter-cell, and then each of these daughter-cells divides again in a manner rather like mitosis, so that there is no further change in chromosome number. Meiosis is essential in any species that reproduces sexually. Sexual reproduction involves a combining of two gametes in the process of fertilization. Fertilization doubles the chromosome number. So there has to be one point in the life-cycle at which the number is halved again. All sexually reproducing organisms must have one meiosis and one fertilization in each life-cycle. The relative timing of meiosis and fertilization differs in different species. Humans, like many but not all animals, leave meiosis until gamete formation. This means that every cell in the life-cycle is diploid except the gametes. In plants meiosis always forms spores. These divide by mitosis to form a number of haploid cells (very few in flowering plants, but more in simpler plants). In some algae and fungi the zygote divides by meiosis, so that the zygote is the only diploid cell in the life-cycle.
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∙ 15y ago
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Explain the human life cycle and the roles of meiosis and mitosis?
Ok, first you start out with the sperm fertilizing the egg, making eventually a two cell embryo. During mitosis, each embryo divides in two making four embryos. This is the process of mitosis. The embryos make up a fetus, and as the fetus develops, it comes closer and closer to birth. Finally, a baby is born and it grows into an adult. Then the adult starts the cycle all over again with the fertilization of the egg.
What stage in the cell cycle performs the most important roles?
The organelles replicate in the G1 phase of interphase.
Are the chromosomes single or double in meiosis?
Before mitosis the chromosome replicates a perfect copy of itself that is attached to itself. After mitosis each of these chromotids has moved to a seperate cell. The chromotid that has moved to the new cell is actually classed as a chromosome. Biologists have made this confusing by the way we are taught about chromosomes as we are shown them when they are in their visible form. They are only visible before mitosis when they bunch up tightly and become more dense and have replicated their DNA resulting in the double strand. The "chromatid" that moves to the new cell is in fact a new chromosome but the visual aid used to teach about chromosomes is the standard image of a double stranded "chromosome". Another key point i have found is that IPMAT (Inter, Meta, Pro, Ana and Telephase) as i was taught is not technically correct. Mitosis doesnt begin until the Prophase, the cell spends a large part of its life in the interphase which happens to be when the chromosome has been replicated in preperation for mitosis and also for other reasons. This is when it becomes double stranded again and apparently stays in the interphase for the majority of the time. A chromosome is also a single strand of DNA, thats something else that is worth remembering. It is tightly wound around proteins to help condense it and be able to fit it all into a cell nucleus, these are called histones and play key roles. Now if i could just figure out why some of the strands in a pair look different to one another when you look at autosomes on wikipaedia i will be happy. Autosomes just refer to chromosomes that aren't the sex determining chromosomes (X or Y)
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It stores and passes on genes. Deoxyribonucleic acid (DNA) contains the code for the genes. Chromosomes are condensed DNA. It is formed on preparation of replication.
What are the three major roles of fats in living organisms?
Formation of membranes - phospholipid bilayer Energy store - used in Krebs cycle in respiration Insulation - retains heat
What roles do chromosomes play in organisms?
They contain genetic information and is a form of DNA. It is copied during mitosis and meiosis.
Explain the human life cycle and the roles of meiosis and mitosis?
Ok, first you start out with the sperm fertilizing the egg, making eventually a two cell embryo. During mitosis, each embryo divides in two making four embryos. This is the process of mitosis. The embryos make up a fetus, and as the fetus develops, it comes closer and closer to birth. Finally, a baby is born and it grows into an adult. Then the adult starts the cycle all over again with the fertilization of the egg.
What stage in the cell cycle performs the most important roles?
The organelles replicate in the G1 phase of interphase.
What are the roles of the nucleus cytoplasm and cell membrane in eukaryotic cells?
the answer is " i'm awesome".
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Oceans have important role. It is a part of water cycle.
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two cultural achievements made in early china
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They are all required to drive the carbon/energy cycle.
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They are all required to drive the carbon/energy cycle.
What are the roles producers consumers and decomposers in an ecosystem?
They are all required to drive the carbon/energy cycle.
What are the roles of producers consumers decomposers in ecosystem?
They are all required to drive the carbon/energy cycle.
