bili

A like a double helix looking molecule that carries the genetic information as a code out of four different bases.

A stretch of DNA that codes for a specific protein that determine the characteristics of a cell.

A chromosome is an entire chain of DNA with stabilizing proteins called histones.

Chromosomes are in the nucleus and they exist the most time in an uncoiled form but then the cell is about to divide the chromosomes coil up again to make the cell division easier.

There are to possible versions of chromosomes that can appear that would be one chromotide chromosomes and two chromotide chromosomes the difference between them is that that the two chromotide chromosomes have an second chromotide that is an exact copy of the other chromotide.

Homologous chromosomes are called the chromosome pairs where one chromosome is inherited from the mother and the other on from the father.

Both chromosomes carry the same genes but they have different alleles which means that both chromosomes carry the same type of information with a different code. For example both chromosomes carry the gene for eye colour but the chromosome from the father have an allel for blue eyes and the chromosome of the mother an allel that is for brown eyes.

A human has 23 homologous chromosomes (chromosome pairs) which means that in a cell are 46 chromosomes in total.

These terms stand for how many how many sets of the same chromosome a cell have

Diploid cells have two sets of every chromosome on from the mother and one from the father.

Haploid cells have only one set of each chromosome. For example gametes (cells for sexual reproduction) are haploid.

Mitosis also called cell division is the process where a single cell divide itself into two identical daughters cells. This process is needed for growth and healing wounds.

1.Interphase: the dna gets replicated

2.prophas: The DNA condenses slowly into two chromotide chromosomes and the nucleus starts to dissolve

3.metaphase: The chromosomes line up in the middle of the cell

4.anaphase: The two chromotide chromosomes are getting separated and pulled apart to the different poles of the cell by the mitotic spindle

5.telophase: two new nuklei form around each group of chromosomes and the cell plate forms across the middle of the cell

6.cytokinesis: the cell divides itself into two separate cells

Meiosis is the process where gametes (cells for sexual reproduction) are made. It is a special type of cell division which occur in pregamete cells.

Meiosis 1:

1.interphase 1: the DNA gets replicated

2.prophase 1: the chromosomes condens and homologous chromosomes pair up

3.metaphase 1:the homologous chromosomes line up in the middle of the cell

4.anaphase1:the homologous chromosomes are getting separated and pulled to the different poles and the cell divides itself into two intermediate cells

Meiosis 2(comes after meiosis 1):

1.prophase 2: Spindel apparatus forms and the chromosomes migrate towards the middle of the cell

2.metaphase 2: the chromosomes line up in the middle of the cell

3.anaphase 2:the two chromotide chromosomes get separated and pulled towards the poles of the cell

4.telophase 2: the cell divides into two different gametes.