Mitosis and Meiosis

Mitosis and Meiosis Tutorial for 9th grade biology students Click anywhere to begin! Made by Ellen Brown

Welcome to this biology tutorial! Let’s get started! First, let me introduce your navigation tools. Then click the next slide button to continue Previous slide Table of Contents Next slide Skip to Quiz

Table of Contents Click to skip to desired section • Introduction • Mitosis • Mini Quiz on Mitosis • Meiosis • Mini Quiz on Meiosis • Final Test

Introduction pt.1 • Mitosis is a type of cell division that occurs in multicellular organisms. It is used to grow and repair damaged tissue. Resulting cells (called daughter cells) are identical to the parent cell. • Meiosis is a type of cell division used during sexual reproduction. Gametes (sex cells) are haploid.

Introduction pt.2 • When learning about cell division, it is essential to know what chromosomes are. • Chromosomes are DNA molecules containing genetic information. http://www.accessexcellence.org/AE/AEPC/NIH/images/chromosome.gif

Diagram of Chromosomes

Introduction pt.3 Chromosomes vs. Chromatids? • These are both chromosomes because they each have a centromere. But the duplicated one is made up of two chromatids, connected in the middle by a centromere.

Introduction pt.4 Diploid vs. Haploid? • If the parent cell has 4N (4 chromosomes), the daughter cell of mitosis will also have 4N, which is called diploid. • The daughter cell of meiosis will have 2N, half the amount, which is called haploid.

Mitosis • There will be a short quiz on the material in this section.

Mitotic Stages: Overview 1. Interphase 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase I *Memorize the order of these stages! P M A T

Mitosis: Interphase • DNA replicates

Mitosis: Prophase • Chromosomes coil and become visible. • Nuclear membrane disintegrates

Mitosis: Metaphase • Chromosomes align along the equatorial axis.

Mitosis: Anaphase • Chromatids separate and begin moving towards the poles.

Mitosis: Telophase • Cell physically divides and nucleus reforms in each daughter cell.

Mini Quiz on Mitosis When you’re ready, click the next slide button to take the quiz.

Question 1: Which of these photos shows metaphase? Click on the correct photo.

Correct! Well Done!

Wrong The correct answer was

Question 2: At what stage in mitosis do chromosomes begin to be visible? Interphase Prophase Metaphase Anaphase

Wrong The correct answer was Prophase

Question 3: What is the correct order of the five stages of Mitosis? Prophase, Anaphase, Interphase, Telophase, Metaphase Metaphase, Anaphase, Prophase, Telophase, Interphase Interphase, Prophase, Metaphase, Anaphase, Telophase Interphase, Metaphase, Anaphase, Prophase, Telophase

Wrong The correct answer was Interphase, Prophase, Metaphase, Anaphase, Telophase. Remember I-P-M-A-T

Meiosis • There will be a short quiz on the material in this section.

Meiosis Stages: Overview Meiosis has two parts, Meiosis I and Meiosis II.

Meiosis I: Prophase Meiosis I is just like Mitosis, except during the prophase stage. Prophase in Meiosis I involves homologous chromosome pairs.

Meiosis I: Prophase Crossing over (the exchange of genetic material) occurs between homologous chromosomes which results in variation.

Meiosis I: Metaphase • Homologous chromosomes line up on equatorial plate.

Meiosis I: Anaphase • Homologous chromosomes move to opposite poles of the cell

Meiosis I: Telophase • Cell divides

Meiosis II: Prophase • Chromosomes condense again, but DNA does not replicate.

Meiosis II: Metaphase • Chromatids line up across equatorial planes

Meiosis II: Anaphase • Chromatids separate, becoming individual chromosomes.

Meiosis II: Telophase • Chromosomes gather into nucleus and the cells divide.

Products of Meiosis • Each of the 4 cells have a nucleus with a haploid number of chromosomes compared to stage 1.

Mini Quiz on Meiosis When you’re ready, click the next slide button to take the quiz.

Question 1: If the parent cell has 16 chromosomes, how many chromosomes would the daughter cell have after meiosis? 16 8 4

Wrong The correct answer was 8 Remember that meiosis results in haploid daughter cells.

Question 2: In which stage does crossing-over occur? Meiosis I: Prophase Meiosis 2: Prophase Meiosis 1: Metaphase Meiosis 1: Anaphase Meiosis 2: Anaphase

Wrong The correct answer was Meiosis I: Prophase

You’re now ready to take the final test! • If you want to review more, click on the table of contents button and you can choose a section to go over. When you’re ready, click the next slide button.

Test Question 1: How many chromosomes are in this cell? Hint: This is Meiosis II Anaphase. 8 4 2

Wrong The correct answer was 4

Test Question 2: In which stage does DNA replication not occur? Mitosis: Interphase Meiosis I: Interphase Mitosis II: Interphase

Mitosis and Meiosis