Download Body Cells

Tuesday, November
st
1 !

• HSAP is next semester! Let’s practice with
some biology—write your answers in your
journal—remember, notebook check coming
up VERY soon.
• You have 5 minutes after the tardy bell RINGS
to complete this. That’s it. We’ll go over it
tomorrow. GET BUSY and STAY BUSY today.
• Page 172 in your book
• “Interpret a Bar Graph” Section,
Questions 1-3
6.1 KEY CONCEPT
Gametes have half the number of
chromosomes that body cells have.
YOU have 2 major cell types!
Body cells
Most of body tissues, organs
NOT passed on to kids
body cells
Develop from germ cells (In ovaries
and testes)
Gametes = sex cells (egg and sperm)!
DNA IS passed to kids
sex cells (sperm) sex cells (egg)
Your cells have autosomes and sex
chromosomes!
• Your body cells have 23
pairs of chromosomes!
– Homologous pairs =
same structure.
– One chromosome
comes from each
parent.
• Autosomes =
chromosome pairs 1-22
• Sex chromosomes = X
and Y, determine gender
are chroms
#1 – 22, NON-sex
chroms (have lots
of other genes)
A Homologous pair =
1 from each parent!!
(same genes, but
may “code” for diff
traits)
Pair #23 = Sex
chroms = X & Y,
genes determine
gender!!
What’s the difference here???
•Body cells!
•2 copies of
every
chromosome
•Half the
chromosomes
comes from
each parent!
•Gametes!
(sperm, egg)
•1 copy of
every
chromosome:
• 22
autosomes
• 1 sex
chromosome
Body Cells
How are these
processes
alike?
Different??
Sex
Cells!!!
Body Cells (Somatic)
Body Cells
Sex Cells (Gametes)
Review!!!
• Where are germ cells located in the human body?
• What’s an autosome?
• What’s a sex chromosome & how’s it different from
an autosome?
• In a human DIPLOID cell, how many chromosomes
are there?
• In a human HAPLOID cell, how many chromosomes?
• After fertilization takes place (sperm meets egg), the
resulting cell (zygote) is .... Diploid or haploid?
• Do you think the Y chromosome contains genes that
are crucial to the organism’s survival?
• Does mitosis or meiosis occur more frequently in
your body?
6.2 KEY
CONCEPT
During
meiosis,
diploid cells
go thru 2
cell
divisions to
make haploid
Meiosis =
2
rounds of cell
division!!
• Meiosis reduces chromosome
number and creates genetic
diversity!
Meiosis I and meiosis II each have four phases,
similar to those in mitosis!!
•Similar, not
identical – 1 from
each parent (same
genes)
•Pairs separate in
Meiosis I
•Copies of the same
chromosome! (each =
½ of duplicated
chrom, attached @
centromere)
•Separate in M. 2
Meiosis I
• occurs after DNA has been replicated
• divides homologous chromosomes into 4
phases.
Turn to p. 174 – 175!
Describe the steps of Meiosis!!

• Meiosis II divides sister chromatids in four phases.
• DNA is not replicated between meiosis I and
meiosis II.
How are they different????
– Meiosis = two cell divisions, mitosis =
one
– In mitosis, homologous chromosomes never
pair up.
– Meiosis results in haploid cells; mitosis
results in diploid cells.
Haploid cells develop into mature gametes.
• Gametogenesis =
production of gametes.
• Gametogenesis differs
between females and
males! 
– Sperm become streamlined and
motile.
– Sperm mostly just contribute
their DNA to the embryo.
– Eggs contribute DNA, cytoplasm, and
organelles to an embryo. Go GIRL!
– During meiosis, the egg gets most of the
contents; the other cells form “polar
bodies”.
More Review for you!!!
• What is mitosis??
• What is meiosis?
• What is a somatic cell??
• What are gametes???
• Examples of gametes???
• Examples of somatic cells??
• What are autosomes??
• Why are the X and Y chromosome
special???
And MORE Review for
you!!!
• What is the difference between
haploid and diploid cells??
• What is a homologous
chromosome??
• A sister chromatid??
• What is gametogenesis??
Circle Activity for Meiosis Practice!
Practice Sheet with Gametogenesis!
• Smart Board Activity