Mitosis & Meiosis Review: Study with Video Lessons, Practice Problems & Examples

Mitosis and meiosis are two types of cell division with distinct functions. In mitosis, sister chromatids separate, resulting in two identical daughter cells, while meiosis I involves the separation of homologous chromosomes, leading to genetic diversity. Both processes require DNA replication prior to division. Understanding these differences is crucial for grasping concepts like genetic variation and the role of meiosis in sexual reproduction.

Mitosis & Meiosis Review Example 1

Okay, everyone. Which of the following statements describes a difference between mitosis and meiosis 1 in a diploid organism? Okay. So let's have a look. Answer choice a says, sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis 1. I don't see anything wrong with this statement. This makes total sense. This is a great answer. Let's look at the other ones. Answer choice b says, sister chromatids separate in mitosis and in meiosis 1. This is not true. Remember that sister chromatids separate in mitosis and meiosis number 2. So this is not correct. Answer choice c says, DNA replication takes place prior to mitosis, but not before meiosis 1. Absolutely not. We know that DNA replication is going to occur before both types of cellular division, mitosis and meiosis. Answer choice d says only meiosis 1 results in daughter cells that contain identical genetic information. That's not true. That's only going to be mitosis. So the correct answer here is answer choice a. A major difference between mitosis and meiosis 1 is that sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis 1. Okay, everyone. Let's move on to our next video.

During which of the following processes do sister chromatids separate from each other?

a) During meiosis I only.

b) During meiosis II only.

c) During both mitosis and meiosis I.

d) During both mitosis and meiosis II.

• A. During meiosis I only.
• B. During meiosis II only.
• C. During both mitosis and meiosis I.
• D. During both mitosis and meiosis II.

Which of the following statements describes a difference between meiosis II and mitosis in a diploid organism?

a) Sister chromatids align along the metaphase plate in mitosis while homologous chromosomes align in meiosis II.

b) Sister chromatids separate in mitosis and homologous chromosomes separate in meiosis II.

c) Meiosis II occurs in a haploid cell, while mitosis occurs in a diploid cell.

d) Crossing over of chromosomes takes place in meiosis II and does not take place in mitosis.

• A. Sister chromatids align along the metaphase plate in mitosis while homologous chromosomes align in meiosis II.
• B. Sister chromatids separate in mitosis and homologous chromosomes separate in meiosis II.
• C. Meiosis II occurs in a haploid cell, while mitosis occurs in a diploid cell.
• D. Crossing over of chromosomes takes place in meiosis II and does not take place in mitosis.

Which of the following processes occurs in meiosis but not in mitosis?

a) Chromosome replication during interphase.

b) Synapsis of chromosomes during prophase.

c) Alignment of chromosomes at the center of the cell.

d) Condensation of chromosomes during prophase.

e) None of the above.

• A. Chromosome replication during interphase.
• B. Synapsis of chromosomes during prophase.
• C. Alignment of chromosomes at the center of the cell.
• D. Condensation of chromosomes during prophase.
• E. None of the above.

What does it mean when we say that mitosis and meiosis II are forms of 'equational division' while meiosis I is a form of 'reductional division'?

a) Daughter cells of mitosis and meiosis II are both diploid while the daughter cells of meiosis I are haploid.  

b) The number of chromosomes in daughter cells of meiosis I is half the number of chromosomes of the parent cell.  

c) The number of chromosomes in daughter cells of mitosis and meiosis II is equal to the number of chromosomes in the parent cells.  

d) A and B.

e) B and C.

f) All of the above.

• A. Daughter cells of mitosis and meiosis II are both diploid while the daughter cells of meiosis I are haploid.
• B. The number of chromosomes in daughter cells of meiosis I is half the number of chromosomes of the parent cell.
• C. The number of chromosomes in daughter cells of mitosis and meiosis II is equal to the number of chromosomes in the parent cells.
• D. A and B.
• E. B and C.
• F. All of the above.

Here’s what students ask on this topic:

What is the main difference between mitosis and meiosis?

The main difference between mitosis and meiosis lies in their outcomes and processes. Mitosis results in two genetically identical daughter cells, each with the same number of chromosomes as the parent cell. It involves one division cycle where sister chromatids separate. In contrast, meiosis consists of two division cycles (meiosis I and meiosis II) and results in four genetically diverse daughter cells, each with half the number of chromosomes of the parent cell. Meiosis I separates homologous chromosomes, while meiosis II separates sister chromatids. This reduction in chromosome number is crucial for sexual reproduction, ensuring genetic diversity.

Why is DNA replication important before mitosis and meiosis?

DNA replication is crucial before both mitosis and meiosis because it ensures that each daughter cell receives a complete set of genetic information. During the S phase of the cell cycle, DNA is replicated, resulting in two identical copies of each chromosome, known as sister chromatids. In mitosis, these sister chromatids are separated into two identical daughter cells. In meiosis, DNA replication occurs before meiosis I, ensuring that homologous chromosomes can be properly separated, and then sister chromatids are separated in meiosis II. Without DNA replication, cells would not have the necessary genetic material to function properly.

How does meiosis contribute to genetic diversity?

Meiosis contributes to genetic diversity through two main mechanisms: crossing over and independent assortment. During prophase I of meiosis, homologous chromosomes pair up and exchange genetic material in a process called crossing over. This results in new combinations of genes on each chromosome. Additionally, during metaphase I, homologous chromosome pairs align randomly at the cell's equator, leading to independent assortment. This random distribution of maternal and paternal chromosomes to the daughter cells further increases genetic variation. These processes ensure that each gamete (sperm or egg) is genetically unique, contributing to the genetic diversity of offspring.

What are sister chromatids and when do they separate in mitosis and meiosis?

Sister chromatids are two identical copies of a single chromosome that are connected by a centromere. They are formed during DNA replication in the S phase of the cell cycle. In mitosis, sister chromatids separate during anaphase, ensuring that each daughter cell receives an identical set of chromosomes. In meiosis, sister chromatids do not separate during meiosis I; instead, homologous chromosomes are separated. Sister chromatids finally separate during anaphase II of meiosis II, resulting in four genetically diverse haploid cells. This separation is crucial for maintaining the correct chromosome number in sexually reproducing organisms.

What role does meiosis play in sexual reproduction?

Meiosis plays a critical role in sexual reproduction by producing gametes (sperm and eggs) with half the number of chromosomes as the parent cell. This reduction in chromosome number is essential because it ensures that when two gametes fuse during fertilization, the resulting zygote has the correct diploid number of chromosomes. Meiosis also introduces genetic diversity through crossing over and independent assortment, which are vital for the evolution and adaptation of species. The genetic variation produced by meiosis contributes to the unique combination of traits in offspring, enhancing the survival and adaptability of populations.