Download Cell Division Notes

CELL DIVISION
PAGE 1
Warm up-Where are your genes located?
_________________________________________________________________
From DNA to Chromosomes

During most of the cell’s life, DNA forms a tangled mass called _____________.

______________ looks like a plate of ______________________.

Right before a cell divides, the chromatin forms into
chromosomes (____________________).
CHROMATIN
MOST OF THE TIME
CHROMOSOMES
ONCE IN A WHILE
Chromosomes




Chromosomes = Tightly coiled, rod-shaped DNA
Chromosomes are made of ___________________
Human body produces 2 trillion cells per day & 25 million per second
Cells are formed by ______ ______________ of older cells
1. When a cell divides, _______ is first copied & then distributed
2. Each cell ends up with a complete _____ of DNA
Chromosome Number
•
Each human _______________ cell has 2 copies of 23 different chromosomes
–
–
Total ______
______________ = any cell that is ______ a _______ _________.
Sets of Chromosomes
•
Each _____________ is made up of 2 __________________ chromosomes
– Homologous chromosomes = chromosomes that are similar in _________ ,
___________, & _____________ __________________.
– Each homologue comes from one of the parents
• One from ___________ One from_________________
Cells Can Be Diploid or Haploid
•
_____________ = a cell that contains __ sets of chromosomes (2n)
•
_____________ (monoploid) = a cell that contains only __ set of chromosomes
(1n or n)
Chromosomes Determine Your Gender
•
Humans have ___ ____________ of chromosomes
•
22 pairs are ________________ (chromosomes NOT directly involved in
determining sex)
•
1 pair are _____ chromosomes (contain genes that WILL determine the sex)
–
___ & ____ chromosomes
X & Y Chromosomes
•
•
•
•
Male = ____
Female = ____
Male (dad) can donate an ___ or a ___ to offspring
Female (mom) can ONLY donate an ___
So-Which parent determines the sex of the baby? _________________
Gametes

Gametes are ________________ _____________.
-Males = _________ (n = ____ )
-Females = _______ (n = ____ )
Combine in fertilization to make a ________________ (n = ____ )
CELL DIVISION
PAGE 2
Diploid means ________________
Haploid means __________________
Gamete is a generic term for ______________ _______________.
Examples of gametes: _______________________ ________________________
Circle the correct choice>>>>>>>>>>
Somatic cells refers to every ________________________ cell in the body except gametes
Examples of somatic cells:



___________________________________
___________________________________
__________________________________
Circle the correct choice>>>>>>>>>>
Mathematically speaking: If haploid = n, then diploid = _______
OR
Haploid is ___________of diploid
OR
Diploid is __________haploid
JUST CHECKING WHAT YOU KNOW
(circle the correct anwer)
Humans have 46 chromosomes in their somatic cells. These cells are:
HAPLOID
DIPLOID
Humans have 23 chromosomes in their gametes. These cells are :
HAPLOID
DIPLOID
If humans diploid number = 46, what is the haploid number?
23
92
If humans haploid number = 23, what is the diploid number?
46
92
If chimps diploid number = 48, what is the haploid number?
24
96
If chimps haploid number = 24, what is the diploid number?
48
96
If humans diploid number = 46, how many chromosomes in a liver cell?
23
46
If humans diploid number = 46, how many chromosomes in a sperm cell?
23
46
If humans diploid number = 46, how many chromosomes in a brain cell?
23
46
If humans diploid number = 46, how many chromosomes in a lung cell?
23
46
If humans diploid number = 46, how many chromosomes in an egg cell?
23
46
If humans diploid number = 46, how many chromosomes in a skin cell?
23
46
************************REMEMBER************************
Sperm or Egg = Gametes = Haploid = n
2n
All Other Cells = Somatic Cells = Diploid =
************************REMEMBER************************
If a chimp’s haploid number = 24, how many chromosomes in a liver cell?
24
48
If a chimp’s haploid number = 24, how many chromosomes in a egg cell?
24
48
If a horse’s diploid number = 64, how many chromosomes in a liver cell?
32
64
If an alligator’s diploid number = 32, how many chromosomes in a liver cell?
32
64
If a dog’s diploid number = 78, how many chromosomes in a sperm cell?
39
78
CELL DIVISION
PAGE 3
Karyotype
•
________________ = a ____________ of the chromosomes in a dividing cell
that shows the chromosomes arranged by _________.
•
Each of an individual’s _____ chromosomes has thousands of genes so the
presence of all chromosomes is essential for normal functioning
–
Humans who are ____________ a chromosome don’t survive
–
Humans with _______ _______ two copies of a chromosome, called
_____________, may survive but will not develop properly.
The Cell Cycle
•
__________ sequence of cell _________ and _______ during an organism’s life
•
90% of cell life is spent in __________________________
•
Then it may go into ____________________ & ____________________
Interphase (has 3 mini-phases)
•
•
•
G1(first growth) phase = _________________________________________
S (synthesis) phase = _________________________________
G2 (2nd growth) phase = _____________________________________
•
Then will go into MITOSIS & CYTOKINESIS (depending on cell type)
Phases of the Cell Cycle
a. prophase
b. G1
c. telophase
d. metaphase
e. G2
f. cytokinesis
g. S
h. anaphase
Cell Reproduction
Mitosis and Meiosis
•
Mitosis:
-division of ______________ (body) cells
-results in two ______________ cells that are ____________
•
Meiosis
-division of _______________ (sex cells)
I
P
M
A
T
CELL DIVISION
PAGE 4
When Control is Lost – CANCER
Cancer = Cell growth is ___________ - does not _______ to control mechanisms.
Causes: ______________ that cause over-production of ______ molecules –
(accelerator) or by in-activating proteins that ___________ the cell cycle (brakes)
__________ and _________ linked to increased cancer risk.
Change in Chromosome Number
Trisomy = humans with ____ than 2 copies of chromosomes - _________ development
Karyotype = a ____________ of the chromosomes in a dividing cell.
Disjunction = when egg/sperm cells form – each chromosome and homologue separate –
sometimes one or more chromosomes _____ to separate - ____________ distribution.
Down Syndrome - ___ copies of chromosome ____ - NONDISJUNCTION
Change in Chromosome Structure
Mutations – A __________ in an organism’s ____________ structure.
1. Deletion = piece of chromosome _________ off completely – lacks of a set of
______________ - fatal
2. Duplication = chromosome fragment _______ to hom. chromosome - ____ copies
of a gene set
3. Inversion = chromosome piece reattaches to _________ chromosome, but in
_____________orientation.
4. Translocation = chromosome piece reattaches to a ____________ chromosome.
MITOSIS

________________ things happen!
1. Cell preparing to divide
2. Genetic material _______________

Chromosomes ________ ___!
1. Chromosomes thicken and shorten
-become visible
-2 chromatids joined by a centromere
2. _____________ move to the opposite
sides of the nucleus
3. _____________ disappears

Chromosomes _________ __ ____ _________!
1. Chromosomes arrange at equator of cell
2. Become attached to spindle fibres by centromeres
3. Homologous chromosomes do not associate
INTERPHASE
PROPHASE
METAPHASE

Chromosomes get pulled ____________
1. Spindle fibres contract pulling chromatids to the
opposite poles of the cell
ANAPHASE

TELOPHASE
Now there are almost ______!
1. Chromosomes uncoil
2. Spindle fibres disintegrate
3. Centrioles replicate
*Cell Divides and Cytokinesis occurs
CYTOKINESIS = cell splits
CYTOKINESIS
CELL DIVISION
PAGE 5
Review – List the stages of Mitosis in order.
___________ - ___________ - ___________ - ___________ - ___________
Meiosis
Meiosis - ______ ___________ that produces only haploid cells (half the number of
chromosomes).
*____________________________
*____________________________
*____________________________
Meiosis Occurs in Two Stages
1.
2.
Follows the same order as MITOSIS but it does it _________________________.
Meiosis I

Homologous chromosomes are separated into ______________ __________.
Interphase

_____________________________________________________________
Prophase I


_____________________________________________________________
_____________________________________________________________
Crossing Over


Exchanging corresponding segments of ____________
Important because it gives a new combination of ______________.
Crossing Over
Metaphase I

_____________________________________________________________
Anaphase I

_____________________________________________________________
Telophase I


_____________________________________________________________
_____________________________________________________________
Meosis II

_______________ of each chromosome are separated into separate cells.
Prophase II

_____________________________________________________________
CELL DIVISION
PAGE 6
Metaphase II

_____________________________________________________________
Anaphase II

_____________________________________________________________
Telophase II


_____________________________________________________________
_____________________________________________________________
End Result of Meiosis and Cytokinesis

____ new cells each with half as much ______________ information as the
parent.
Mitosis and Meiosis Practice Quiz
1. Mitosis is a cellular process that produces
a. Two genetically identical daughter cells
b. Four genetically identical daughter cells
c. Two similar, but not genetically identical daughter cells
2. The first stage of mitosis where chromatin condenses to form chromosomes is
a. Interphase
b. Prophase
c. Anaphase
3. The part of the cell cycle where a cell spends most of the time carrying on
metabolism
a. Interphase
b. Prophase
c. Metaphase
4. The stage of mitosis where the chromosomes line up at the cells’ equator
a. Prophase
b. Metaphase
c. Anaphase
5. The stage of mitosis where the spindle fibers pull the chromatids toward the
centrioles
a. Prophase
b. Anaphase
c. Telophase
6. The stage of mitosis shown in the diagram.
a. Prophase
b. Metaphase
c. Anaphase
7. The stage of mitosis shown in the diagram.
a. Metaphase
b. Anaphase
c. Telophase
8. What is the function of a centromere?
a. To hold sister chromatids together
b. To pull the chromosomes
c. To push the chromosomes
9. How many gametes form from a parent cell that undergoes meiosis I & II?
a. 2
b. 3
c. 4
10. Gametes have the ______ number of chromosomes
a. Diploid
b. Haploid
c. Polyploid
11. A zygote has the ______ number of chromosomes
a. Diploid
b. Haploid
c. Polyploid