Study GuideBiology–Meiosis and Gamete Formation1. MeiosisMost plant and animal cells arediploid.The worddiploidcomes from the Greek worddiplos, meaning “double.” This means diploid cells havepairs of chromosomes.For example, human body cells contain46 chromosomes, arranged into23 pairs. Because thereare two copies of each chromosome, human body cells are diploid.1.1 Diploid vs. Haploid CellsSexual reproduction involves special cells calledgametes(sex cells).•In humans, gametes aresperm cellsandegg cells•Gametes arehaploid, meaning they containonly one set of chromosomesThe wordhaploidcomes from the Greek wordhaplos, meaning “single.”Human gametes contain23 chromosomes, which is half of the usual 46.When a sperm and an egg join during fertilization, they form azygote.This restores thediploid number (46 chromosomes). After that,mitosisallows the zygote to growinto a multicellular organism.1.2 What Is Meiosis?Meiosisis the type of cell division that produces gametes.Its main purpose is to:•Cut the chromosome number in half•Producefour haploid cellsfromone diploid cellIn humans, this means:Preview Mode
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