What term best describes a cell with one set of chromosomes or half the number of chromosomes as the parent cell?
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NOTIFICATIONSAlthough we are all unique, there are often obvious similarities within families. Maybe you have the same nose as your brother or red hair like your mother? Family similarities occur because we inherit traits from our parents (in the form of the genes that contribute to the traits). This passing of genes from one generation to the next is called heredity. Simple organisms pass on genes by duplicating their genetic information and then splitting to form an identical organism. More complex organisms, including humans, produce specialised sex cells (gametes) that carry half of the genetic information, then combine these to form new organisms. The process that produces gametes is called meiosis. Meiosis makes sperm and eggsDuring meiosis in humans, 1 diploid cell (with 46 chromosomes or 23 pairs) undergoes 2 cycles of cell division but only 1 round of DNA replication. The result is 4 haploid daughter cells known as gametes or egg and sperm cells (each with 23 chromosomes – 1 from each pair in the diploid cell). At conception, an egg cell and a sperm cell combine to form a zygote (46 chromosomes or 23 pairs). This is the 1st cell of a new individual. The halving of the number of chromosomes in gametes ensures that zygotes have the same number of chromosomes from one generation to the next. This is critical for stable sexual reproduction through successive generations. The phases of meiosis in humans
Genetic variation is increased by meiosisDuring fertilisation, 1 gamete from each parent combines to form a zygote. Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA. This produces a unique combination of genes in the resulting zygote. Recombination or crossing over occurs during prophase I. Homologous chromosomes – 1 inherited from each parent – pair along their lengths, gene by gene. Breaks occur along the chromosomes, and they rejoin, trading some of their genes. The chromosomes now have genes in a unique combination. Independent assortment is the process where the chromosomes move randomly to separate poles during meiosis. A gamete will end up with 23 chromosomes after meiosis, but independent assortment means that each gamete will have 1 of many different combinations of chromosomes. This reshuffling of genes into unique combinations increases the genetic variation in a population and explains the variation we see between siblings with the same parents. Useful linkVisit the Learn Genetics website to go on an animated tour of the basics. View the ‘What is inheritance?’ and ‘What is a trait’ segments to find out more about inheritance and variation. Would you like to take a short survey?This survey will open in a new tab and you can fill it out after your visit to the site.
What is it called when a cell has half the number of chromosomes?Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction.
What is it called when a cell has one set of chromosomes?Haploid. A haploid cell has only a single set of chromosomes. Most cells in humans are diploid rather than haploid, meaning they have two copies of each chromosome.
What is a cell with one set of chromosomes or half the number of chromosomes as the parent cell?The overall process of meiosis produces four daughter cells from one single parent cell. Each daughter cell is haploid, because it has half the number of chromosomes as the original parent cell.
What is the term for a cell that has half the regular number of chromosomes or one copy of each pair of homologous chromosomes?Cells with homologous chromosomes are diploid. Reproductive cells, called gametes, are different. They contain only half the full number of chromosomes—one chromosome from each pair. These cells are haploid.
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