What is a chromosome?

humans have 46 a fly has eight and an elephant has 56. so what am i talking about chromosomes welcome to moomoomath and science and what is a chromosome inside the nucleus of a eukaryotic cell is a strand of dna the dna is the genetic blueprint and directions for making proteins the proteins are responsible for traits such as hair color and eye color the dna on chromosomes is arranged in segments called genes which are the instructions for the proteins that create the traits this strand of dna is very long in fact if you were to stretch it out it would be five feet in length roughly during the prophase portion of mitosis this strand of dna begins to condense and become visible the dna begins to coil around histone proteins the dna twists and coils itself and creates a chromosome which looks kind of like an x let's take a look at the chromosome in a little bit more detail you'll notice it has two sides that are by and large identical these are so called sister chromatid and they are held together by a centromere a sister chromatid refers to the identical copies formed by the dna replication of a chromosome with both copies joined together by a sentiment a full set of sister chromatids is created during the s phase of interphase when all the chromosomes in a cell are replicated the two sister chromatids are separated from each other into two different cells during mitosis during mitosis the sister chromatids separate into daughter cells but are now referred to as a chromosomes but sometimes you will see chromosomes represented like this this is a karyotype in humans the sister chromatids cross over during meiosis and create homologous chromosomes which are two chromosomes in which one is from the male and the other is from the female they have the same genes in the same order but they have different alleles and allele is a different form of the same trait karyotype is a picture of these homologous chromosomes humans have 23 pairs of these homologous chromosomes for 46 total chromosomes other organisms have different numbers and combinations thanks for watching and remember kindness multiplies kindness be kind to someone today

Channel: MooMooMath and Science

Views: 23,037

Keywords: chromosomes, dna, genetics, heredity, sister chromatids, traits

Id: 8yK4RfzCYU4

Length: 2min 45sec (165 seconds)

Published: Sat Jun 11 2022