Mitosis and Meiosis: Cell Division
Comparing how cells grow, repair, and form gametes
Mitosis and Meiosis: Cell Division
Comparing how cells grow, repair, and form gametes
Biology - Grade 9-12
- 1
State one main purpose of mitosis in multicellular organisms.
Think about how your body heals a cut or grows taller.
One main purpose of mitosis is to produce new body cells for growth, repair, and replacement of damaged or old cells. - 2
State one main purpose of meiosis in sexually reproducing organisms.
One main purpose of meiosis is to produce gametes, such as sperm or egg cells, with half the usual number of chromosomes. - 3
Compare the number of cell divisions in mitosis and meiosis.
Count how many times one parent cell splits.
Mitosis has one cell division, while meiosis has two cell divisions called meiosis I and meiosis II. - 4
A diploid cell has 46 chromosomes. After mitosis, how many chromosomes will each daughter cell have?
Each daughter cell will have 46 chromosomes because mitosis produces genetically similar diploid cells. - 5
A diploid human cell has 46 chromosomes. After meiosis, how many chromosomes will each gamete have?
Gametes are haploid, not diploid.
Each gamete will have 23 chromosomes because meiosis reduces the chromosome number by half. - 6
Explain the difference between diploid and haploid cells.
Diploid cells have two sets of chromosomes, one from each parent, while haploid cells have only one set of chromosomes. - 7
During which process do homologous chromosomes pair up and exchange genetic material through crossing over?
This event increases genetic variation and does not happen in ordinary body cell division.
Homologous chromosomes pair up and exchange genetic material through crossing over during meiosis, specifically in prophase I. - 8
Describe one reason meiosis leads to genetic variation but mitosis usually does not.
Meiosis leads to genetic variation because crossing over and independent assortment create new combinations of alleles, while mitosis usually produces genetically identical cells. - 9
Name the stage of mitosis in which sister chromatids separate and move to opposite poles of the cell.
This happens after the chromosomes line up in the middle of the cell.
The stage is anaphase, when sister chromatids separate and move to opposite ends of the cell. - 10
What are the four main stages of mitosis in order?
The four main stages of mitosis in order are prophase, metaphase, anaphase, and telophase. - 11
Compare the final products of mitosis and meiosis in terms of number of cells and genetic similarity.
Include both the number of cells and whether they are similar or different.
Mitosis produces two genetically similar daughter cells, while meiosis produces four genetically different haploid cells. - 12
Why is it important for chromosome number to be reduced before fertilization in sexual reproduction?
It is important because reducing the chromosome number in gametes prevents the chromosome number from doubling every generation, so fertilization restores the normal diploid number.