Chapter 8 section 1 Cell reproduction  What is DNA?  Contains information that determines the Characteristics of an organism.

Chromosomes  Rod shaped structure made up of DNA and proteins.  Found in the nucleus of the cell.  DNA  Chromosomes  Nucleus  Cell

 DNA wraps around proteins called histones.  Histones maintain the shape of the chromosomes and aid in the first packing of DNA.

 Chromosomes consists of two identical halves.  Each half is called Chromatid.  Chromatids are attached at the Centromere.

Chromosomes  Each species has a characteristic number of chromosomes in the cell.  Human 46 FLY 8  Cat 32 Carrot 18  Dog 78

Sex chromosomes  Determine if the organism is a female or male.  Humans have X or Y chromosomes.  Female has two X chromosomes  Male have an X and a Y chromosomes.

Humans  44 chromosomes are called autosomes.  2 chromosomes are sex chromosomes.

 The two copies of each autosomes are called homologous chromosomes.

 Karyotype: photomicrograph of chromosomes.

Chapter 8 section 1 Cells  What is DNA?  Contains information that determines the Characteristics of an organism.

Chromosomes  Rod shaped structure made up of DNA and proteins.  Found in the nucleus of the cell.  DNA --> Chromosomes -->Nucleus -->Cell

 Human have 46 chromosomes

 Female has two X chromosomes XX  Male have an X and a Y chromosomes. XY

Humans  44 chromosomes are called autosomes.  2 chromosomes are sex chromosomes.

 Karyotype: photomicrograph of chromosomes.