what is a zygote please tell in detail
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Answers
Answer:
zygote is a single cell formed by fusion of sperm and egg in the ovary which develops into a baby. plz mark brainliest.
Explanation:
A zygote is the cell formed when two gametes fuse during fertilization. The DNA material from the two cells is combined in the resulting zygote. The cellular mechanisms present in the gametes also function in the zygote, but the newly fused DNA produces a different effect in the new cell. In single-celled organisms, the zygote becomes a fully functioning organism, and can divide through mitosis to produce offspring. The organism can also produce gametes to reproduce sexually with other cells.
Multicellular organisms use a similar process, producing gametes that fuse during fertilization to produce a zygote. The zygote then undergoes many round of mitosis to produce an entire organism. Depending on the size of the organism at birth, the development time of the young can vary. The African elephant, for instance, has a gestation time of over 20 months, or over a year and a half. Some rodents, on the other hand, only need two weeks or so before babies can be born. It all depends on how many cells are needed in the final organism, and how developed the organism is at birth.
In most animals, the gamete cells are converted to haploid cells before reproduction, in a process known as meiosis. By reducing the number of alleles in each gene to 1, a zygote formed by two haploid gametes will have the proper number of alleles. This is important in most animals, as the wrong number of chromosomes or alleles can produce negative effects. The well-known genetic defect Down Syndrome is caused by an extra 21st chromosome in humans. In most vertebrates besides fish, extra copies of alleles are usually detrimental.
In plants, the condition of more than two alleles in a zygote is not always detrimental. Often, plants have many copies of a gene with different alleles. Many plants do not undergo meiosis before reproducing by accident, and therefore are prone to accumulating many copies of a chromosomes as generations continue to reproduce. The zygote that forms from accidental gametes can create a novel varieties of plants. Many commercial agricultural crops are the results of polyploidy affecting the plant in some way, either making them bigger or making their fruits sterile so people cannot grow them and must buy more. Besides these differences in plants, a zygote is still formed when two gametes fuse. In many higher plants, the zygote forms when the pollen fertilizes an egg inside of ovules in the flower. The process is detailed in the following image.
In fungi, the process of forming a zygote is a little different, because fungi have somewhat different lifecycles. Many fungi are haploid the majority of the time. Sometimes haploid cells combine through a process of karyogamy, or combining of nuclei. This produces a diploid organism for a short time. During this time, important genetic variation and recombination can take place, allowing fungi to remain adaptive in the face of adversity.
Examples of Zygote
Puppy development
Who doesn’t love a puppy? The process of creating a puppy starts by creating gametes. In both the male and female, the process of meiosis reduces the number of alleles in each cell to 1 instead of 2. Once the gametes are made, the animals must mate. The male dog’s sperm make their way to the female’s eggs as they travel from her fallopian tubes to her uterus. Once an egg and sperm meet, fertilization occurs. During fertilization, the sperm combines DNA with the egg, producing one cell. This single cell is now known as the zygote. The zygote will divide through mitosis. Eventually, the cells will start to specialize and continue dividing. In time they will create a litter of puppies, which the female will birth. The puppies are still not fully developed, and take several weeks to open their ears and eyes fully.
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