Sexual Reproduction &
Meiosis
Why It’s Important
They are the reasons why no one
else is exactly like you
Sexual Reproduction
• 2 sex cells, sperm & egg, join to form a
zygote, which will develop into a new
organism with a unique identity
A human egg & sperm at
fertilization
Sex Cells
• Sperm- male sex cell (formed from
meiosis)
• Egg- female sex cell (formed from
meiosis)
Vocabulary
• Fertilization- joining
of sperm & egg
 Forms a zygote
• Zygote- a diploid cell
•
formed when sperm
and egg join
Diploid Cells- body
cells; cells with pairs
of chromosomes
 Skin, bone, brain cells, etc
• Haploid Cells- cells
with HALF the
number of
chromosomes as
body cells
 Sperm & Egg
 Haploid is Half of
Diploid!
You Try It
• Q: How many chromosomes are in a
•
•
•
•
human’s body cell?
A: That’s Right! 46
Q: How many chromosomes would be in a
human sex cell (haploid cell)?
A: YES…23
Why?- Haploid cells have HALF the # of
chromosomes as Diploid cells
How are sex cells formed?
 Meiosis- process by
which the number of
chromosomes is
reduced by half to
form sex cells
• Ensures offspring will
have the same # of
chromosomes as the
parent
Fertilization
Fertilization Activity: Guess
Who!!!!
Kangaroo 16
Opposum 22
Snail 24
Corn 20
Cabbage 18
Slime: What is it????
• Objective: Determine the state of matter of
slime.
• How is your slime like a solid?
• How is your slime like a liquid?
• What state of matter were the slime
ingredients?
Meiosis Review
• 1) If the haploid # of a • 3) The giant panda’s
•
white-tailed deer is
35. How many
chromosomes would
be in their sex cells?
2) A rabbit has a
haploid number of 22.
What is the number of
chromosomes in the
zygote of a rabbit?
diplioid number is 42.
What is its haploid
number?
• 4) The hyena has 40
chromosomes in its
body cells. How many
chromosomes are in
its sex cells?
Haploid v. Diploid
• 1. _______________: body cells,
• 4. If the diploid number of a
koala’s body cell is 16, what would
be the haploid number?
has double (or pairs) of
chromosomes.
• 2. _________________: sex
• 5. A fruit fly has 3 chromosomes
cells, had half the number of
chromosomes in the body cells.
•
• 3. If dogs have 39 chromosomes
in their sex cells, how many
chromosomes are in their body
cells?
•
in their sex cells. How many
chromosomes would be present in
the zygote?
6. The diploid number for a rabbit
is 44. How many chromosomes
are in their sex cells?
•
7. A spinach haploid cell contains
5 chromosomes. How many
chromosomes are in spinach’s
diploid cell?