Name: __________________________  Date: _____________  Period: _______ 

Chromosome Worksheet

Background: Diploid/somatic cells always have an even number of chromosomes because they exist in pairs (2n). Haploid/sex cells contain only half the number of chromosomes (n). An example of haploid cells is sperm found in male species and eggs found in female species. One unique set of chromosomes are found in the father's sperm (n) and one unique complementary set is found in the mother's egg (n). When the sperm fertilizes the egg, it becomes a diploid cell (n + n = 2n).

EXAMPLE: In our somatic cells are 23 pairs of chromosomes or 2n=46. In our sex cells, we have 23 unique chromosomes or n=23.

Complete the following table of chromosome number in various species. Notice that the number of homologous chromosome is the same as the number of chromosomes found in a haploid cell.

Species Number of chromosomes in diploid cells (2n)

Number of homologous

chromosome pairs in diploid cells

Number of chromosomes in haploid cells (n)

Homo sapiens 2n=46 23 pairs n=23

Fruit fly 2n=8

leopard frog 2n=26

housefly

n=6 monkey

n=21 bat

22 pairs

chicken

39 pairs

king crab

104 pairs

camel 2n=70

goat

n=30

armadillo

n=32

petunia

7 pairs

rice 2n=24

 

TURN OVER   

Questions:

1. Dogs have 78 chromosomes in their diploid cells. How many chromosomes are in their haploid cells?

2. How many pairs of chromosomes do dogs have in their somatic cells?

3. Cats have 38 chromosomes in their diploid cells. How many chromosomes are in their haploid cells?

4. Horses have 32 chromosomes in their sex cells. How many chromosomes are in their somatic cells?

5. How many chromosome pairs do horses have in their somatic cells?

6. Wheat has 42 chromosomes in its diploid cell. How many chromosomes are in the haploid cells?

7. What is a karyotype?

8. Identify the following karyotype as male or female:

 

Mitosis Worksheet

Name: __________________________________ Date: ____________

1. Label the following diagram with the phase of mitosis, (a) through (e), or the type of cell structure, (f) through (h), seen during mitosis.

2. During which stage of a cell’s cycle do the replicated chromosomes thicken and

become visible? ______________________

3. During which stage of a cell's cycle do the replicated chromosomes line up on the equator of the cell? ______________________

4. During which stage of a cell's cycle do the chromosomes replicate? ____________

5. The drawing below has been made from a photograph showing a cell undergoing mitosis. Based on the drawing, in what stage of mitosis must the cell have been in?

______________________

6. The drawings A-E show stages of mitosis in an plant cell.

(a) Which of the drawings A -E shows

(i) interphase ________ (DNA is replicated)

(ii) prophase ________ (chromosomes – 2 sister chromatids – shorten)

(iii) metaphase ________ (sister chromatids line up)

(iv) anaphase ________ (sister chromatids separate)

(v) telophase ________ (new nucleus forms at each end)

(vi) cytokinesis ________ (cell contents divided between 2 daughter cells)

(b) Give two processes which occur during interphase and which are necessary for mitosis to take place. ____________________ of the cell and ____________________ of the DNA

7. This drawings shows various stages of mitosis in a fast growing onion root tip.

Identify the cells (by number) which are in the following stages of mitosis: interphase _____________

prophase _____________

metaphase _____________

anaphase _____________

telophase _____________

8. Using colored pens or pencils, show how 2 chromosomes are passed from parent cell to two daughter cells.