How many chromosomes do sex cells have
A sex chromosome , also referred to as an allosome , heterotypical chromosome , or heterochromosome , [1] [2] or idiochromosome [3] is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction. Autosomes differ from allosomes because autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell , whereas members of an allosome pair may differ from one another and thereby determine sex. Nettie Stevens and Edmund Beecher Wilson both independently discovered sex chromosomes in However, Stevens is credited for discovering them earlier than Wilson.




How many chromosomes are in a sex cell?




How many chromosomes do people have? - Genetics Home Reference - NIH
Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid DNA. Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. The term chromosome comes from the Greek words for color chroma and body soma. Scientists gave this name to chromosomes because they are cell structures, or bodies, that are strongly stained by some colorful dyes used in research. The unique structure of chromosomes keeps DNA tightly wrapped around spool-like proteins, called histones. Without such packaging, DNA molecules would be too long to fit inside cells.



Chromosomes: Definition & Structure
Chromosomes are thread-like molecules that carry hereditary information for everything from height to eye color. They are made of protein and one molecule of DNA, which contains an organism's genetic instructions, passed down from parents. In humans, animals, and plants, most chromosomes are arranged in pairs within the nucleus of a cell. Humans have 22 of these chromosome pairs, called autosomes. Humans have an additional pair of sex chromosomes for a total of 46 chromosomes.





In sexual reproduction, offspring arise from the union of specialized sex cells — a female egg and a male sperm. Just before the rediscovery of Mendel's work, careful studies were made of chromosome behavior during the formation of sex cells meiosis. First, homologous like chromosomes pair up at the cell equator where they actually exchange genetic information. Then, one chromosome from each pair is pulled toward each pole.

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