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M2A1 Worksheet: Mitosis and Meiosis A dog is a diploid organisms and has 39 pair

ID: 141280 • Letter: M

Question

M2A1 Worksheet: Mitosis and Meiosis

A dog is a diploid organisms and has 39 pairs of chromosomes (2n = 78), where n = 39 chromosomes from each parent. Use this example to answer the following question regarding chromosomal number.

INTERPHASE

How many chromosomes are present in the somatic cell?

What do they look like?

What are they “doing” in G1 of this phase?

What is happening in the S phase?

What is happening in the G2 phase?

What follows G2 phase in a somatic cell?

What follows G2 phase in a gamete cell?

MITOSIS

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in the daughter cell.

Number of chromatids in the daughter cell.

How many daughter cells are produced?

Are the daughter cells haploid or diploid?

How many cell divisions take place?

In what type of cell does this division occur?

Meiosis 1:

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in each Meiosis I daughter cell.

Number of chromatids in each Meiosis I daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis 1?

Meiosis II:

Number of chromosomes in the “parent” cell (which is a daughter cell from Meiosis I).

Number of chromatids in the “parent” cell.

Number of chromosomes in each Meiosis II daughter cell.

Number of chromatids in each Meiosis II daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis II?

Which phase or phases of Meiosis account for the genetic variability among the daughter cells? How… what happens in this phase to create the diversity?

Comparing Mitosis and Meiosis…..

How many daughter cells result from Mitosis? Are they diploid or haploid?

How many daughter cells result from Meiosis? Are they diploid or Haploid?

Cell structures and function:   Match each organelle to its function:

Organelle                                                                        Function

Lysosome                                                         1.            Lipid synthesis

Rough ER                                                         2.            Houses DNA

Nucleus                                                             3.            Energy extraction

Smooth ER                                                       4.            Dismantles debris

Golgi apparatus                                              5.            detoxification

Mitochondria                                                  6.            Protein synthesis

Peroxisome                                                      7.            Processes secretions

What is the function of checkpoint proteins in the cell cycle?

How can all of a person’s cells contain exactly the same genetic material, yet specialize as bone cells, nerve cells, muscle cells and connective tissues?

What are the 3 primary germ layers?

Briefly, in one or two sentences, distinguish between

a bacterial cell and a eukaryotic cell

interphase and mitosis

mitosis and apoptosis

an autosome and a sex chromosome

homologous pair of chromosomes and a sister chromatid

centromere and centriole

chromosome and chromatid

monozygotic and dizygotic twins

allele and gene

Explanation / Answer

Interphase

Answer 1. In a somatic cell, 2n=78 will be found.

Answer 2. These chromosomes will be seen in the form of Chromatin material.

Answer 3. In G1 phase, Chromatin material will be seen and all the enzymes required for DNA replication will be synthesised.

Answer 4. In S phase, DNA replication will occur.

Answer 5. In G2 phase, the cells prepares itself for the latter stage. G1, S and G2 phases are part of Interphase.

Answer 6. After G2, somatic cells shows the mitotic stages starting with Prophase.

Answer 7. After G2, the gametic cells shows the meiosis I phase which basically starts with Prophase I.

Mitosis

Answer 1. The parent cell is having 2n=78.

Answer 2. Per chromosome 2 chromatids are found means 78X2= 156.

Answer 3. Same as answer 1.

Answer 4. Same as answer 2.

Answer 5. 2 daughter cells are produced.

Answer 6. Daughter cells are Diploid.

Answer 7. 2 divisions will occur.

Answer 8. It occurs in the somatic cells

Meiosis I

Answer 1. Parent cell will be having 2n=78

Answer 2. 156 chromatids in parent cell.

Answer 3. Chromosomes will reduce to half in meiosis I in each daughter cell. Thus, it will be 39 in each cell.

Answer 4. Chromatids will be 39 X2 = 78.

Answer 5. Daughter cells will be haploid after meiosis I.

Meiosis II

Answer 1. Parent cell at meiosis II is having n=39

Answer 2. Chromatids will 78 in parent cell.

Answer 3. Daughter cell will have n=39 after meiosis II.

Answer 4. Chromatids same as answer 2.

Answer 5. Daughter cells are haploid after Meiosis II.

Answer 6. Meiosis I- Prophase I- pachytene accounts for genetic variability. Crossing over occurs in this, in which genes are exchanged between the homologous chromosomes.