Kon “chromosomes and inheritance” 1. take the tour titled “what is a chromosome? ” draw a picture that demonstrates how dna is coiled into chromosomes: once you have your drawing, label the following: chromatin, histones, chromatids, chromosome, kinetochore

Chromatin is a complex of DNA and proteins found in eukaryotic cells, with the function to pack DNA in more compact shape and to prevent DNA damage. One of the main components of chromatin are proteins called histones. Histones are directly responsible for DNA package to form structures called nucleosomes. Chromatin can be found in its active form-euchromatin (tuned on genes) and inactive-heterochromatin (turned off genes).  

Chromosomes are organized structures of DNA which are visible in certain stages of cell cycle (such as metaphase when they are aligned). Every chromosome is copied once during the S phase of the cell cycle. It is then found in an X-shaped structure (centromere is located in the middle of the chromosome and two-arm structures are the original chromosome and the copy -sister chromatids).

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: