Diploid
Say it: DIP-loyd
Diploid describes a cell or organism with two complete sets of chromosomes, one inherited from each parent, as in most human body cells.
Also: diploidy
Definition
What does diploid mean?
A diploid cell contains two full sets of chromosomes, written 2n. Each chromosome is present as a matched pair of homologs, which carry the same genes in the same order; one homolog came from the mother and one from the father, so the two may hold different alleles. Human body cells are diploid, with 46 chromosomes in 23 pairs: 22 pairs of autosomes and one pair of sex chromosomes.
Diploidy is kept in balance by the cycle of meiosis and fertilization. Meiosis halves the chromosome number to make haploid gametes, and the fusion of an egg and a sperm restores two sets in the zygote. Mitosis then passes the full diploid set to every new body cell. Having two copies of each gene allows a recessive allele to be masked by a dominant one, which is why a person can carry a recessive condition without showing it.
Most animals and many plants are diploid for most of their life cycle. Some organisms have more than two sets, a state called polyploidy that is common in crop plants: bread wheat has six sets of chromosomes, and cultivated strawberries have eight.
Word parts
Where does the word “diploid” come from?
- diplo-
- double, twofoldGreek diploos
- -oid
- like, having the form ofGreek eidos (form)
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Terms that go with it
- HaploidHaploid describes a cell or organism that has a single set of chromosomes, such as a human egg or sperm cell with 23 chromosomes.
- MeiosisMeiosis is a two-stage cell division that turns one diploid cell into four genetically different haploid cells, the precursors of eggs and sperm.
- ZygoteA zygote is the single diploid cell formed when a sperm fertilizes an egg, carrying one set of chromosomes from each parent.
- ChromosomeA chromosome is a thread-like structure of DNA and protein that carries an organism's genes; most human cells hold 46 of them in 23 pairs.
- HomozygousHomozygous describes an organism that carries two identical alleles of a gene at a given locus, one inherited from each parent.
- HeterozygousHeterozygous describes an organism that carries two different alleles of a gene at a given locus, such as one dominant and one recessive allele.
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Written for biofideX in plain words, after checking these references:
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