Cell
Division
AN OVERVIEW OF REPRODUCTION
Aims:
 Define and distinguish diploid, haploid, gamete, somatic cells
 Compare sexual and asexual reproduction
 Explain the role of binary fission, mitosis and meiosis in reproduction
Agenda:
 Riddle me this…
 Diagram Analysis & Notes
 Whiteboards
 True or False



Animations/Video
Models
Practice
Motivation: Riddle to solve in pairs: Biology is the only subject where multiplication = division. Why?
Development
Introduction to unit
 Elicit from riddle that in order to reproduce and make more cells, cells must divide.
 Refer to cell theory in students’ homework assignment – where do all cells come from?
 Elicit that the trillions of cells in your body all of came from other cells through
division/reproduction.
 Explain that in our unit we will investigate how, when, why the cell divides, and what happens
when division goes wrong. Today we will look at the two types of reproduction
Haploid vs. Diploid Cells
 Tell students that in order to understand cell division, we need to know cell types
 Have students work in partners to analyze karyotypes of somatic & sex cells & complete notes
 Why are these cell types found only in eukaryotes?
 Which parent determines the sex of a baby? Why?
 Use whiteboards and slides of karyotypes to check for understanding
Types of Reproduction
 Show pictures to engage and elicit two types
 What phylum does the hydra belong to? What domain and group does the amoeba belong to?
Asexual Reproduction
 Students analyze slide and work in partners to determine # of parents, how the offspring
compares, how the genes compare, the types of division involved
 Why can’t mitosis occur in prokaryotes?
 Animation at http://www.stolaf.edu/people/giannini/flashanimat/celldivision/crome3.swf
 Cells Alive for more realistic view if time
 Check for understanding with whiteboards – draw parent cell on board, students draw offspring
Sexual Reproduction
 Students analyze slide and work in partners to determine # of parents, how the offspring
compares, how the genes compare, the type of division, fertilization, zygote
 How many of you look exactly like your father, mother, siblings? How can you explain this?
 Elicit sexual reproduction and that some of DNA comes from mom and some from dad
 What process allows the zygote to develop into a baby?
 Check for understanding with whiteboards – draw gametes on board, students draw offspring
 Show videos of fertilization if time (medical animation and funny sperm journey)
Check for Understanding
 Thumbs up/down for true/false statements to elicit misconceptions
 Slides of puzzles and processes
Cell
Division
AN OVERVIEW OF REPRODUCTION
Practice
Models: Students use play-dough to model sexual reproduction of an organism with n=6.
Exit Slip: MC/Free response from AP exam.
Homework: Annotate cell cycle (8.5, 8.8, 8.9) or (10.2)
Cell
Division
AN OVERVIEW OF REPRODUCTION
Do Now
1. Label the cell below with the terms: cell, nucleus, chromosome. Then circle the homologous pairs.
Questions 2-4 refer to the diagram to the right.
2. Which pairs are autosomes and which are sex
chromosomes?
3. Is this a male or female? How do you know?
4.
Is this from a human cell? How do you know?
5. Which set of chromosomes is a homologous pair? Why?
A.
B.
C.
6.
Put the following terms in order from largest to smallest:
gene, DNA, nucleus, chromosome, cell, nucleotide.
Cell
Division
AN OVERVIEW OF REPRODUCTION
Riddle Me This…
Biology is the only subject where multiplication equals division. Why?
______________________________________________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
Cell Theory
All cells come from other ________ through the process of ____________________ or ____________________.
Cell Types
In eukaryotes there are two main types of cells:
1. Body cells, or ______________ cells, are _______________ because they contain both chromosomes
from each homologous pairs. Symbolized by ____. Examples of somatic cells are skin,
_______________ and _________________ cells.
2. Sex cells, or ______________, are _________________ because they contain only one chromosome
from each homologous pair. Symbolized by ___. Examples of sex cells are _________ and
__________.
Cell
Division
AN OVERVIEW OF REPRODUCTION
Two Types of Reproduction
1. ____________ reproduction is the process where ___ parent produces genetically ___________
offspring. This process does NOT increase genetic __________________.
a. Eukaryotic cells: asexual reproduction occurs through the process of ______________. A
_____________ (2n) cell produces two ______________ (2n) cells. This process can also be
used for _____________ and _______________ of cells.
+
b. Prokaryotic cells: asexual reproduction occurs through the process of __________________
_______________. The circular ___________________ replicates and then the cell ____________.
+
2. ____________ reproduction is the process where _____ parents produce offspring that are
genetically _____________ but not _______________. Two ____________ (n) cells, an ________ and
a________, form during the process of _________________ and combine during the process of
______________________to make a ______________ (2n) cell called a __________________. This process
________________ genetic diversity.
23
+
Organisms Often Use Both Types
Cell
Division
AN OVERVIEW OF REPRODUCTION
Practice
1. Determine the haploid number or diploid number for each species in the table below.
Common Name
Genus and Species
Diploid Chromosome
Number
Haploid Chromosome
Number
Buffalo
Bison bison
60
Cat
Felis catus
19
Cattle
Bos taurus, B. indicus
30
Dog
Canis familiaris
78
Goat
Capra hircus
60
Horse
Equus caballus
Human
Homo sapiens
Sheep
Ovis aries
32
46
27
2. Identify each cell as a haploid or diploid and gamete or somatic. Then explain how you know.
A.
B.
C.
D.
3. Identify the whether the process relates to asexual or sexual reproduction:
________ A diploid prokaryote divides to produce two new diploid cells
________ Dead skin cells are replaced by new identical cells
________ Sperm and egg cells fuse
________ An amoeba, a eukaryotic single-celled organism, splits into two diploid cells
________ A zygote is formed
________ Eggs cells
________ Mitosis
________ Two haploid cells combine to form a diploid cell
________ A baby grows into an adult
________ Genetic diversity is increased
________ Genetic diversity is not increased
________ Fertilization is involved
________ One parent
________ Two parents
________ Offspring resemble parents but aren’t identical
________ Offspring are identical to parents
________ Binary fission
________ Meiosis
Cell
Division
AN OVERVIEW OF REPRODUCTION
4. Draw the results of asexual reproduction of each cell and identify whether each is mitosis or binary
fission.
a.
d.
14
ll ll ll ll
b.
e.
c.
f.
ll ll
ll
5. For each example of sexual reproduction, identify each cell as egg, sperm, or zygote and haploid or
diploid. Label the chromosome number in each.
a.
12
+
b.
+
6
c.
+
46
6. Label the diagram with these terms: diploid adult, egg, sperm, haploid gametes, fertilization, diploid
zygote, sexual, asexual, mitosis, meiosis
Cell
Division
AN OVERVIEW OF REPRODUCTION
Venn Diagram
Compare sexual and asexual reproduction using these terms: cells, one parent, two parents, identical
offspring, similar offspring, increases genetic diversity, zygote, gamete, diploid, haploid, egg, sperm
Exit Slip
1. If an intestinal cell in a grasshopper contains 24 chromosomes, a grasshopper sperm cell contains
____________________ chromosomes.
a. 3
b. 6
c. 12
d. 24
e. 48
2. Which of the following is not a function of mitosis in humans?
a. Repair of wounds
b. Growth
c. Production of gametes from diploid cells
d. Replacement of lost or damaged cells
e. Multiplication of somatic cells
3. Bacteria are able to divide on a much faster schedule than eukaryotic cells. Some bacteria can
divide every 20 minutes, while the minimum time required by eukaryotic cells is once per hours,
and most cells divide much less often than that. State at least 2 hypotheses explaining why
bacteria can divide at a faster rate than eukaryotic cells. Use your knowledge of cell structure
and reproduction as evidence to support your hypotheses.
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
Cell
Division
AN OVERVIEW OF REPRODUCTION
Do Now
1. Draw and label a haploid cell (n=2) and a diploid cell (2n=4).
2. Identify and briefly describe two types of reproduction.
3. Label the diagram with these terms: diploid adult, egg, sperm, haploid gametes, fertilization,
diploid zygote, sexual, asexual
4. What process is occurring in the diagram at the right?
5. Draw the results of asexual reproduction of each cell:
14
ll ll ll ll
6. For each example of sexual reproduction, identify each cell as egg, sperm, or zygote and haploid
or diploid. Label the chromosome number in each.
12
+
+
6
Cell
Division
AN OVERVIEW OF REPRODUCTION
Modeling
1.
Sort the chromosomes for the mother and father’s diploid cells into homologous pairs
according to your teacher’s instructions. Be sure to keep the mother’s and father’s
chromosomes separate.
a. How many chromosomes are in each parent’s cells?
b. 2n = ___
2.
Create a hollow egg cell and a hollow sperm cell using play dough.
3.
Put the haploid number of chromosomes from each parent in each cell.
a. How many chromosomes are in each gamete?
b. n=
4.
Fuse the egg cell and sperm cell together. What process is this?
5.
Arrange the chromosomes in homologous pairs. Draw the zygote below.
6.
How does the new cell (zygote) compare to the original diploid parent cells? Be specific.
___________________________________________________________________________________________
___________________________________________________________________________________________
7.
Why isn’t the zygote identical to either the mother or father?
Cell
Division
AN OVERVIEW OF REPRODUCTION
Enzyme Experiment
A group of students performed the following procedure for their experiment.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Measure 50 mL of applesauce into a small beaker.
Hold a dropper bottle containing Enzyme A at a 30 degree angle 5 cm above the beaker.
Slowly add 15 drops of Enzyme A to the applesauce and stir with a stirring rod ten times.
Place a coffee filter into a plastic funnel and place the funnel in a 25 mL graduated cylinder.
Pour the applesauce mixture into the filter in the funnel.
Leave the applesauce filter into the graduated cylinder for 5 minutes.
After 5 minutes, record the amount of juice produced to the nearest tenth of a mL.
Repeat steps 1-7, using 5 drops of Enzyme B.
Repeat steps 1-7, using 15 drops of water.
The table below shows the results of the group’s experiment.
Solution
Amount of Juice Produced (mL)
Enzyme A
10
Enzyme B
6
Water
3
40.
What was the problem the students were investigating? (3 pts)
41.
Identify three constants in this group’s experiment. (3 pts)
42.
What conclusions can be drawn from the students’ experiment and results?
Support your answer with specific information from the table. (3 pts)
43.
44.
How valid are these conclusions? Explain your answer fully. (3 pts)
Which of the following was the independent variable in this experiment?
A. Amount of applesauce
B. Filtering time
C. Type of Enzyme
D. Amount of juice produced
45.
Which of the following was the control group in their experiment?
A. The applesauce
B. Enzyme B
C. Water
D. Enzyme A
Cell
Division
AN OVERVIEW OF REPRODUCTION