Download 2014-2015 PACKET #10

2014-2015
Biology Honor
Name:
Ms. Qotoj
PACKET #10
Unit 5: Reproduction and Heredity, Part 1: Meiosis and Human Reproduction
Objectives:
Sexual Reproduction
1. Compare haploid (n) and diploid cells (2n) (12.2).
2. Differentiate between homologous chromosomes, autosomes*, and sex chromosomes (12.2).
3. Differentiate between somatic cells and gametes (12.2).
Meiosis (12.3)
4. Draw and describe each stage of meiosis.
5. Explain how variation in offspring is created through independent assortment*, crossing-over, and random
fertilization*.
6. Explain how the purpose of meiosis differs from that of mitosis.
7. Draw and describe how meiosis creates gametes (4 sperm cells in $, 1 egg cell in $).
8. Describe some anomalies associated with meiosis, including nondisjunction, trisomy, and monosomy
Human Sexual Reproduction
(12.6-12.10)
11. Identify female reproductive structures on a diagram and describe the function of each (12.7).
12. Identify male reproductive structures on a diagram and describe the function of each (12.8).
13. Describe gamete development in males (12.8).
14. Describe gamete development in females and the stages of the menstrual cycle, including the identity and
roles of the hormones involved (12.7).
15. Describe some anomalies associated with ovulation and fertilization, including monozygotic twins,
dizygotic twins, and other multiple births (supplementary reading).
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Biology Honor
Meiosis
Prophase I
Metaphase I .
Anaphase I
Telophase I
Prophase I I
Metaphase II
Anaphase II
Telophase I I
Variation
Independent assortment
Crossing over
Random fertilization
Karyotype
Nondisjunction
Monosomy
Trisomy
Down syndrome
Turner syndrome
Oogenesis
Spermatogenesis
Diploid (2N)
2014-2015
Haploid (N)
Immature egg or sperm
Mature egg or sperm
Autosome
Sex chromosomes (XX or XY)
Somatic cell
Gamete
Zygote
Ovum (plural = ova)
Ovary
Epididymis
Follicle
Vas deferens
Ovulation
Oocyte
Urethra
Spermatogenesis
Polar bodies
Seminal vesicles
Oogenesis
Corpus Luteum
Prostate
Fallopian Tube (oviduct)
Penis
Ovarian cycle
Uterus
Menstruation
Endometrium
Ejaculation
Cervix
Semen
Vagina
Fertilization
Zygote
Testes
Gestation
Scrotum
Placenta
Seminiferous tubules
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Biology Honor
2014-2015
Meiosis
How does sexual reproduction lead to genetic variation?
Why?
Cells reproduce through mitosis to make exact copies of the original cell. This is done for growth and
repair. Sexually-reproducing organisms have a second form of cell division that produces reproductive cells
with half the number of chromosomes. This process is called meiosis, and without it, humans, oak trees,
beetles, and all other sexually-reproducing organisms would be vastly different than they are today.
Model 1 - Meiosis I
1. According to Model 1, in what type of organs are the cells that enter meiosis I found?
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2. Considering wnat you already know about mitosis in cells, what event must take place during
interphase before a cell proceeds to division?
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Biology Honor
2014-2015
3. "What two structures make up a single replicated chromosome?
Svsvor chromatids (and aiHrorywt)
4. In Model 1, how many replicated chromosomes does the cell contain during prophase?
4
Read This!
Alleles are alternative forms of the same gene. For example, gene A may contain the information for
fur color. One allele "A" may result in white fur, while the alternative allele "a" may result in black fur.
Homologous chromosomes are chromosomes that contain the same genes, although each chromosome
in the homologous pair may have different alleles.
5. At which stage in meiosis I do the pairs of homologous chromosomes come together?
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6. Once the chromosomes have formed a pair, what are they called?
7- At the end of meiosis I , two cells have been produced. How many replicated chromosomes are in
each of these cells?
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8. Cells with a full set of chromosomes are referred to as diploid or 2a, whereas ceils with half the
chromosomes are haploid or a. At which stage(s) of meiosis I are the cells diploid and at which
stage(s) are they haploid?
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•
prophase -» anaphatf.
% 9. Which of the statements below correaly describes the relationship between the cells at the end of
telophase I and the original cell?
a. The new cells have one copy of all of die genetic information in the original cell.
b. The new cells have two copies of all of die genetic information in the original cell.
c. The new cells have one copy of half of the genetic information in the original cell.
^ ? ) T h e new cells have two copies of half of the genetic information in the original cell.
'"%10. Considering the genetic makeup of the homologous pairs, will the cells at the end of telophase I
be genetically identical to each other?
no.
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4
2014-2015
Biology Honor
Model 2 - Meiosis I I
Two cells from
Meiosis I in
Prophase II
Metaphase II
Anaphase II
11. According to Model 2, where did each of the cells come from that started meiosis II?
12. I n meiosis I , during anaphase I , which structures separated—homologous chromosomes or sister
chromatids?
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13. In meiosis I I , during anaphase I I , which structures separated—homologous chromosomes or
sister chromatids? , .
.
t * .
14. At the end of the meiosis I I are four daughter cells. Are they haploid or diploid? Explain your
answer in a complete sentence.
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15. Which of the statements below correctly describes the relationship between the cells at the end of
meiosis I I and the original cell?
a. The new cells have one copy of all of the genetic information in the original cell.
b. The new cells have two copies of all of die genetic information in the original cell.
/ / " " X
( c.J The new cells have one copy of half of the genetic information in the original cell.
d. The new cells have two copies of half of the genetic information in the original cell.
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Biology Honor
2014-2015
Model 3 — Gametogenesis and Fertilization (Human)
Males
Females
Secondary oocyte
(end of meiosis I)
Secondary
spermatocyte
(end of meiosis I)
Oocyte proceeds
to meiosis I I
Polar body
eventually
degenerates
Spermatids
(end of
meiosis II)
Zygote with half its
chromosmes from
the female (maternal)
and half from the
male (paternal)
Mature
sperm
16. According to Model 3, what is the name given to the cells produced at the end of meiosis I in
17. What is the name given to the cells produced at the end of meiosis I in females?
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18. Refer to Model 3.
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a. A t the end of meiosis I I in males, what cells are produced?
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b. What do these cells (from the previous question) eventually become?
19. Before fertilization, what happens to the secondarv oocyte?
.
20. During fertilization which two cells come together? Be specific in your answer.
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.
a
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2014-2015
21. During meiosis II, the secondary oocyte divides unevenly, with one cell (the ovum) receiving half
of the chromosomes and nearly all the cytoplasm and organelles, while the other cell, the polar
body, is much smaller and eventually degenerates. "With your group, propose an explanation to
explain why the secondary oocyte divides in this way.
upon
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22. What is the ploidy of the zygote produced by fertilization—haploid or diploid?
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*%23. What would the ploidy of the zygote be if egg and sperm were produced by mitosis rather than
meiosis? How would this affect the ploidy of each successive generation?
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'-%24. With your group write a statement to explain the origin of the chromosomes found in the zygote. Your statement must include the term homologous pair.
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7
2014-2015
Biology Honor
Extension Questions
Model 4 — Crossover of DNA in Chromosomes
Chiasma
Homologous pair of chromosomes
(tetrad) during Prophase I
Recombinant chromatids
25. A t which stage of meiosis are the chromosomes in Model 4?
26. When the chromosomes come together as homologous pairs, the arms of the sister chromatids
may cross over.
a. What are these crossover points called?
b. Describe what happens to the chromatids during crossover.
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27. What phrase is used to describe the chromatids after crossing over takes place and the homologous chromosomes separate?
28. Compare the recombinant chromatids with the original pair.
a. Are the genes on a recombinant chromatid the same as the original chromatid?
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b. Are the alleles on a recombinant chromatid the same as the original chromatid?
VvO.
Biology Honor
2014-2015
Model 5 — Genetic Variation
OR
Early Prophase I
Late Prophase I
Late Teloph
29. Model 5 is a condensed version of meiosis I . Notice the tsvo possible arrangements of chromosomes in late prophase I . Considering what you know about DNA replication and meiosis, is
either arrangement equally likely during the formation of tetrads in late prophase I? Explain.
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of mch (pair
30. I f theje were three sets of homologous chromosomes in the cell in Model 5, how many possible
arrangements would there be for the tetrads in late prophase I?
a
3
.
D
Read This!
When homologous chromosome pairs align on the spindle during metaphase I die orientation of one pair
is independent of the orientation of any other pair. This is known as independent assortment. Humans
have 46 chromosomes, arranged as 23 pairs. During metaphase I each pair lines up independently, which
results in 2 possible combinations.
23
31. With your group, calculate the number of possible genetic combinations due to independent
assortment.
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Biology Honor
2014-2015
32. As a group, choose one set of daughter cells in late telophase I from Model 5. Imagine that those
cells now undergo meiosis I I . Draw at least four resulting haploid cells that could result.
33. Meiosis and sexual reproduction each lead to variation i n the genetic make-up of every person.
W i t h your group, explain how meiotic events, as well as the random fertilization of eggs and
sperm, together lead to this genetic variation.
5/12/15
Human Karyotype
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W e h a v e pairs o f c h r o m o s o m e s i n o u r cells
•
O n e c o p y of e a c h c h r o m o s o m e f r o m m o m ; o n e from d a d .
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These pairs a r e said t o b e h a n i c i o a o i . i s ; fhey c o n t a i n i h e
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9
a
aa
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ill) M U
13
16
14
15
10
every h u m a n ceil.
22 pairs a r e
autosome:,
in
21
p a i r s = 46
c h r o m o s o m e s in
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1
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17
l d
pair are
chromosome:,
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22
23
19
•
XX f o r f e m a l e
•
XY f o r m a l e
X Y
Male
X x
Female
Human Karyotype
if
Recessive
allele
Bb
PP
Homozygous
Heterozygous
Homozygous
for the
for the
dominant allele r e c e s s i v e allele
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alleles.
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15
10
16
17
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21
22
T w o divisions t a k e
inherited o n e of
e a c h pair from
mom, the other
from d a d .
When your body
11
12
18
19
g a m e t e s , it w i l l
shuffle these
chromosomes
a r o u n d t o pass
one of e a c h o n to
your offspring.
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9
X X
Female
place
•
Meiosis 1 - s e p a r a t i o n o f
homologous chromosomes. Pi,
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M e i o s i s 2 - s e p a r a t i o n o f sister
chromalids. P , Mj, A , T .
M l , A,.T,
Meiosis: C e l l division i h a l p r o d u c e s h a p l o i d (n) ceils
(gametes)
9
II III II «8 M M
H o m o l o g o u s chromosomes m a y h a v e t h e s a m e or differeni
2
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23 H o m o i o g o u s
produces
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p
Genotype:
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1
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V
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Dominant
allele
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5
4
11
n
Gene loci
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T h e r e m a y b e d i f f e r e n i a l l e l e s [versions} o f a single g e n e .
Chromosomes c a n b e organized inlo a kor/oiypr-.
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t".l
same genes a i specific loci.
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N o h o m o l o g o u s c h r o m o s o m e p a i r s in h a p l o i d
W h y is m e i o s i s i m p o r t a n l ?
•
Sexual reproduction
•
G e n e i i c variation a m o n g offspring
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5/12/15
Meiosis Results in Offspring Variation
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H o m o l o g u e s line
u p . 2 possible
orientations. 50%
3 M a j o r w a y s m e i o s i s is d i f f e r e n t f r o m m i t o s i s :
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C e i l d i v i d e s 2x, b u t o n l y r e p l i c a t e s D N A t x .
Results in h a p l o i d
p.
cells.
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for.each.
independent
apartment.
Distributes r a n d o m mixture of p a r e n t g e n e s ( i n d e p e n d e n t
Q: How
a s s o r t if ve-rif}
n
chance
T h i s is c a l l e d
1
H o m o i o g o u s c h r o m o s o m e s pair u p d u r i n g l ' cell-jHere, they o f t e n e x c h a n g e g e n e s
c t o s s l n g o*>e-r
\
many
different
combinations
(gametes) c a n
cell with 2n = A
make?
a
Biology Honor
2014-2015
23
Biology Honor
1. How many replicated chromosomes are pictured?
j
I
2. How many homologous chromosome pairs are pictured?
2014-2015
0 4
3. How many different genes are pictured?
4. How many genes relate to hair texture?
5. Of the chromosomes present, how many were paternally-inherited?
6. Of the chromosomes present, how many were maternally-inherited?
(yi
7. Did this person inherit the "normal" version of the hemoglobin gene from both paternal and maternal sides?
8. Did this person inherit the "normal" version of the p53 gene from both paternal and maternal sides?
9. What is the difference between the "normal" version of the hemoglobin gene, and the "abnormal" version of the
hemoglobin gene? flfl A iS ^ ( Q O j l UTtth QJT
10. What letter is used to abbreviate the "normal" version of the hemoglobin gene? .
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11. What letter is used to abbreviate the "abnormal" version of the hemoglobin gene?
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12. Do you
that this person will make "normal" hemoglobin proteins, or "abnormal" hemoglobin proteins?
)u think
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13. Will this person have Sickle Cell Anemia?
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14. This person has inherited "normal'Vnon-mutated p53 genes. So, when the cell divides in mitosis, each new cell
will get two copies of the "normal" version of the p53 gene. Does this mean that ALL cells will have "normal"
versions of the 53 gene? f\Q
Explain . j U l ^
f j f l f l o ( \gP
.
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15. There are three genes here relating to hair texture. Assume that all three genes weigh equally in terms of what
the person will look like. So, this is an example of a "transcription unit," when multiple genes together
determine the outcome or an appearance. Do you think that this person will have straight, wavy, curly, or very
curly hair?
16. If there are 20,000 genes in a human genome, approximately how many genes are present on each homologous
pair of chromosomes? fyYO (So this diagram clearly doesn't show enough genes on each homologous pair.)
17. What percentage of genes do human share with one another?
(6b
18. What percentage of A/C/G/T sequence do humans share with one another?
19. As we have learned before, out of the 3,000,000,000 "letters" in the human genome, the majority of A/C/G/T
sequences are considered "noncoding," as they do not directly code for proteins made by the cells' ribosomes.
Based on this diagram, identify three different locations of "noncoding" A/C/G/T sequences.
2014-2015
Biology Honor
Crossing Over Practice:
Paired chromosomes at t h e b e g i n n i n g
o f meisois are analogous t o pairs o f
instruction m a n u a l pages.
Chromosomes a f t e r crossing over
contain information f r o m maternal
a n d paternal chromosomes.
The diagram below shows a pair of homologous chromosomes
about to undergo chiasma formation during the first cell division
in the process of meiosis. There are known crossover points
along the length of the chromatids (same on all four chromatids
shown in the diagram). In the prepared spaces below, draw
the gene sequences after crossing over has occ_-e:
unrelated and separate occasions (it would be _ssdifferent coloured pens to represent the genes
different chromosomes). See the diagrams on the
as a guide.
a b c d e f
g
h
a
g
h
.b
c d e
f
i
Homologous
chromosomes
i
j
k g
j
k
6
I
rn
n
o
. p ) - Chromatid 1
m
n
o
p ) - Chromatid 2
7
8
11
i
HI
J
9*-
K L M N OP
mum
Possible knewcrossover poin:;
on the chroma: :
1
Chromatid 3
Chromatid 4
1. Crossing over occurs at a single point
between the chromosomes above.
(a) Draw the gene sequences for the four
chromatids (on the right), after crossing
over has occurred at crossover point: 2.
hxXMJLmm.
T
' VI I , X
(b) List which genes have been exchanged
with those on its homologue (neighbour
chromosome):
Crossing over occurs at two points between
the chromosomes above.
(a) Draw the gene sequences for the four
chromatids (on the right), after crossing
oyer has occurred between crossover
points: 6 and 7.
nop
\
2
(b) List which genes have been exchanged
with those on its homologue (neighbour
chromosome):
11
2014-2015
Biology Honor
Independent Assortment Practice:
P r e c w w i ceSis to j p e t m and
ogi;<, hove 2 t o p i c * of
« , K h «lwonxKOrr.« ~ t h a t is, 2 full i c t i of
i r u l r u c f s o n m a n u a l pog-et, ! from e * c h parent.
S p e r m a/id -05.3 ooll< h-svi- e o l y 1 full tut — 0
r a n d o m <0/iibirwilica of m a t e r n a l a n d p a t e r n a l
ircsUucfion m a n u a l p.ig-ei.
In hum.j.-is, er.Vf 8 million
c o m b l n - a t i c m are
costibte.
V
Page 5
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gofH' f r c r n m o m
(f 01 it m o r n
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Page 9
O l o c d x j r o u p rjena
Eyft•<&!<!,' g e n e t
f r o m rnrxn
/>Offl dfld
E « h « g g a n d t p o n n It unit;ui:>, T h b I n j u r e U M S tho I m t r u c i i c n inarvw.it a n a l o g y to s h o w h e w .1
iinijU' n u n 6*n p p x I i K p on I ' l x i n r x x j s tihttuv/
of tfMjrni, The w m c p r s x e t i of i n d e p e n d e n t . H s o r t m e m r r t u h i
in t j n o r m t x n diver tity I n eg<n . n v w l l . T h o
t h a i J f c t h o l e u r c c o f „i m-wi't t p c r n i « r i y 2 of ca<h chfOrno-
s i r r w — t r u t is. 2 fi-il < p p i « - of the artarwilion rrnmunJ-—1 set. iibtfi
hit morn, t h e d O W from hit tf.td. W h e n 0
t j w m cell it p r o d u < . « J , it e » d t u p w i t h o n l y 1 copy 0*1 e i i l i p.tge. Since
C - K I U K O T
i j p r o d u c e d ind.>{i«r>a*ntly.
the w t of p.iQO-, in c j t h t p c m wi-U b o s •jnifju.; t c r n b i t i j u o n o f "ho p-irjs-i lh.it tho r>vm inherited from hit
morn .j^.rj rt.td.
Biology Honor
2014-2015
Comparing Mitosis and Meiosis:
Mitosis
Meiosis
Purpose of the process
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Location(s) in the human
body where this process
occurs
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cms
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Are the products the same or
different, as compared to one
another?
Number of products formed?
Number of rounds of
division?
Products are diploid or
haploid?
If the original cell had 6
replicated chromosomes, this
is how the cell would look in
metaphase (refer to
metaphase I for meiosis).
You must use six different
colors here, and you must
write a caption beneath each
picture (use terms like
replicated chromosome,
homologous chromosome,
etc.).
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_
H
o?
i
CMvwO^J^B
are
ttrui
art
If the original cell has 6
replicated chromosomes, this
is how the cell would look in
Metaphase I I of meiosis. Use
different colors here! You
must also write a caption
below the picture.
Utrudl t f
ar4Uaivlc*f
N/A
C h r o m o s o m e s
UAtu^
13
Biology Honor
2014-2015
(^MVUOAU AW\A|V\
si a metagenesis la animal:
•••A \1 ' ^ - - f
2M
Spermatogonium
<spemi)
_
\
- 'I
Primary
- ) spermatocyte
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Oogonium
Primar/
oocyte
2N
FX
Secondary
I spermatocyte 'IN
polar body
Secondary /
oocyte, *
^
\ ? -y
J
y
/
i Spermatids
1
i
V
f I
4
Ootid /
;
-y
CHfftiiOnLiatiOil
v
Sperm
\
Ovum
\
r-
Second
polar body
Polar bodies
' g i t mojc/e*/
f
f
CO-'
Spermatogenesis Class Notes:
Oogenesis Class Notes:
-l+appead ^-testes
~ioo (vul\t(Msperm w M t ^ d a u
-tfapptfism
ovaries
~W\eNfc-to ef\di(UjvvviS -Jar f \ ^ a h ( Y )
6IM
p r i i r m ^ m o o a i i e
a>otwuie&
ID meiosi's ~u£ (Caused »h rretor
14
J
Biology Honor
2014-2015
Oogenesis and Spermatogenesis Comparison Chart
Oogenesis
Spermatogenesis
Meiosis or mitosis?
____
Purpose of the process
„
•
ma)uL
Location of the process
• —
—
—
s p e r m
teS+vs
Number of products formed
Number of products capable of
participating in fertilization
Do the products need to develop
further after meiosis EE (before
fertilization)?
Are the products equal in size?
Explain.
¥
1
yes
no
3SWLU
-po\aY
bodies
T
5C<3in - b e f o r e birth
When during a person's lifetime
does the process begin? When does
the process complete?
S j
Are the primary oocytes or
spermatocytes present at birth?
Produced via
mitosis or
meiosis?
yes
Genetically
unique or
identical?
„.is-r.
-
WO
Diploid or
haploid?
Immature eggs
(primary
oocytes) and
immature sperm
(primary
spermatocytes)
Mature eggs and
mature sperm
Xjf I f - -y-- V — o -
# of homologous # o f
chromosome
chromosomes?
pairs?
13
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0
23
15
5 / 1 3 / 1 5
OBJ 19
Errors in Meiosis
Nondisjunction — failure of
chromosome separation in
anaphase I or II of meiosis
P
Anaphase I - homologues
don t separate
•
Anaphase II-sister
chromatids don't separate
D
Results in gametes with
abnormal numbers of .
chromosomes
D
(20% to 50% of miscarriages
result from fertilization of
gametes with abnormal
numbers of chromosomes)
"Nondisjunction
/ \
Meiosis II
A
K
Nondisjunction
(X)
/
G a m e too
i9!
\
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n+1
n-\
i
n-1
ill
:
n+1
n-1
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Number of chromosomas
a
n.+•]-=.trisomy'-
f •
n-1 - monosomy
1
j
OBJ 1£
OBJ 19
Errors in Meiosis (cont.;
Nondisjunction of autosomes (non-sex
chromosomes)
• Trisomy 21—Down syndrome
Effects include mental retardation, eyes that
slant upward, and heart defects
It affects over 350,000 people in the United
States alone and is the most common (1 in 800
live births) imbalance in the number of
autosomes in people.
i|
Errors in Meiosis (cont.i
Nondisjunction of sex chromosomes
• Turner's syndrome (XO)
•
Klinefelter^ syndrome (XXY)
1
• XYY males
1
Biology Honor
2014-2015
Nondisjunction, Trisomy & Monosomy
How could a zygote (fertilized egg) have three 21st chromosomes (Down Syndrome)?
WoR: 1Wc
W
NiOfWAL-
^
,
How could a zygote (fertilized egg) have one X and zero Y chromosomes (Turner Syndrome)?
WoH: 1Wc J l w U
Normal
\t
Nondisjunction
occurs on sex
chromosomes
16
Biology Honor
2014-2015
Putting it all Together!
Use 4 different colors to show 4 different chromosomes in the cells from the paternal side. Then use 4 separate
colors to show the chromosomes from the maternal side. Use size to distinguish between homologous pairs.
So, in all, you will need 8 colors. Track these chromosomes (by using color) throughout the processes below.
Ignore crossing over.
17
Biology Honor
2014-2015
Meiosis practice (with a little mitosis, too)
1. The drawing on the right is of the sperm cell of a certain animal. The sperm cell has four chromosomes.
a. Give the number of chromosomes in a stomach cell of the animal indicated.
b. Make the diagram of the mature egg cell of this animal, showing the chromosomes.
c. Make a diagram of the zygote of this animal, showing the chromosomes.
d. Make a diagram of the 2-celled stage of this embryo, showing the chromosomes.
2. In a certain animal cell, the diploid number is 10. Give the number of chromosomes found in:
-a mature sperm cell
-a zygote
-a mature egg cell
-a skin cell
3. The following questions refer to the diagrams below
i
r
v.)
I
a. The cell indicated by the letter A is a
• ' i • :/
/
. It is manufactured in the
b. The process that results in the formation of cell C is
,. Cell C is produced in the
c. The chromosome number in cells A and B is produced by the process of
d. Cell C will immediately begin to
e. The chromosome number of cell C is called
.
.
_ _ , while that of cells A and B is called
18
Biology Honor
2014-2015
4. Label each of the following statements as being descriptive of prophase I , metaphase I , anaphase I ,
telophase I , prophase I I , metaphase I I , anaphase I I , or telophase II of meiosis.
gametes fully formed
sister chromatids split apart
. homologous chromosomes split apart
homologous chromosomes line up two-by-two
replicated chromosomes line up single file
5. Name the three processes whereby genetic diversity is increased. Describe two of these processes.
6. A donkey somatic (body) cell contains 62 chromosomes, and a horse somatic cell contains 64 chromosomes.
The donkey and horse can mate to produce a mule. However, a mule is sterile as mule cells cannot undergo
meiosis. Explain why mitosis is normal in mule cells, but why the mixed set of chromosomes interferes
with meiosis.
7. A micrograph of a dividing cell from a mouse showed 19 replicated chromosomes, each consisting of two
chromatids. (Picture is shown below.) Could this picture have been taken in prophase I of meiosis? Why
or why not? Could this picture have been taken in anaphase of mitosis? Why or why not? What about
prophase II of meiosis?
8. The diagram below represents metaphase II of meiosis in a cell that had two pairs of homologous
chromosomes. Draw a diagram showing how cells from this same (multicellular, sexually-reproducing)
organism would look in metaphase of mitosis.
iy
Biology Honor
2014-2015
3. Shown below is a cell that has just finished telophase of mitosis (including cytokinesis). In the boxes that
follow, show how a cell would look (from the same organism) in each of the stages listed.
Metaphase I - Meiosis
Anaphase I I - Meiosis
Prophase - Mitosis
4. If the diploid number is 50, there are
(how many?) homologous chromosome pairs.
5. If the diploid number is 30, there are
(how many?) chromosomes per gamete.
6. If there are 40 replicated chromosomes at the beginning of meiosis, one would expect
(how many?)
(replicated or unreplicated?) chromosomes per gamete at the end of meiosis. Each gamete
has
(what fraction?) of the DNA mass of the original cell entering meiosis (after interphase). Each
gamete has
. (what fraction?) of the genetic information of the original cell (after interphase).
7. At the end of mitosis, each daughter cell has
(what fraction?) of the DNA mass of the original cell
entering mitosis (after interphase). Each daughter cell has
(what fraction?) of the genetic information
of the original cell (after interphase).
8. Human somatic (body) cells have
9. Human gametes have
(how many?) chromosomes.
(how many?) chromosomes.
21
Biology Honor
2014-2015
Figure 1: Female Reproductive Anatomy - side view
25