Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. During mitosis, a single cell divides to produce two daughter cells. What must happen inthe
original cell so that each of the daughter cells has a complete set of chromosomes?
The DNA must replicate
2. During sexual reproduction, two sex cells fuse to create a fertilized cell with a complete setof
chromosomes. What must be true about the number of chromosomes in each sex cell?
There must be 2 one x and one y or both X.
Gizmo Warm-up
Meiosis is a type of cell division that results in four daughter cells
with half as many chromosomes as the parent cell.
These daughter cells mature into gametes, or sex cells. In the
Meiosis Gizmo, you will learn the steps in meiosis and
experiment to produce customized sex cells and offspring.
On the STEPS tab, click Male. You are looking at a germ cell,
or a cell that will undergo meiosis to become gametes.
1. Read the description of interphase at the bottom of the Gizmo. What happens to the cell at
the beginning of interphase? The cell grows in size and doubles its organelles.
2. Click on the DNA in the nucleus of the cell. Describe what happens. The DNA duplicatesand
allows the cell to continue to grow
3. Why is it necessary for the cell to grow and duplicate its DNA before the start of meiosis?
, Because when a parent cell undergoes mitosis it divides into two daughter cells and they all
need DNA thats why before mitosis takes place there must be a duplicate of the DNA.
Get the Gizmo ready:
Activity A: Steps Make sure the STEPS tab is selected.
in meiosis If necessary, choose the Male cell. Click on the
DNA to copy it to proceed to prophase I.
Introduction: Unlike mitosis, which produces two identical daughter cells from one parent cell,meiosis
creates four unique daughter cells with half the amount of DNA as the parent cell.
Question: How does meiosis create four daughter cells from one parent cell?
1. Observe: (Prophase I) Click on the nucleus to break it down then click on the DNA to
condense it into chromosomes. Drag the centrosomes to the top and bottom of the cell.
A. How many chromosomes does this cell have? 2
Each chromosome consists of a pair of sister
chromatids, two identical strands of DNA that formed
when DNA replicated during interphase.
B. On the image to the right, draw two lines connectingthe
pairs of homologous chromosomes (chromosomes of
similar size with a matching set ofgenes).
In the Gizmo, drag the homologous chromosomes
together. Click Continue.
2. Observe: (Metaphase I and Anaphase I) - Drag the groups of homologous chromosomes tothe
metaphase plate, then drag spindle fibers from each of the centrosomes to the chromosomes. Click the
centrosome to pull the chromosomes apart.
How do the chromosomes separate in anaphase I? The centrosomes attach spindle fibers toeach mom
the chromosomes to pull them apart and to opposites sides of the cell.
3. Compare: An image of the anaphase step in mitosis is shownto the
right.
A. How does anaphase I in meiosis differ from anaphasein
mitosis? key difference between mitosis and meiosis is that
sister chromatids remain joined during
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller QuizMerchant. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £9.82. You're not tied to anything after your purchase.