23 November
Can you remember the two ways that cells
divide and the names of those phases?
At the end of this section, students will be able to:
• explain how new cells are created
• explain why maintaining chromosome number during cell division
is important and how sexual and asexual reproduction may
contribute or limit genetic variation
• describe cancer as uncontrolled cell growth that may have resulted
from mutations affecting cell cycle-regulating proteins
Hypothesis
If I place snails and elodea in separate test tubes than the snails will produce
more carbon dioxide than the elodea because the snails respire more than
plant do.
or
If I place snails and elodea in the same test tube and expose one set of test tubes to
24 hours of light and one set in 24 hours of dark, than there will be less carbon
dioxide in the solution in the light after 24 hours because plant photosynthesize,
in light and take up carbon dioxide, reduce the amount of that gas in solution.
Identify your independent variable
• The number of snails in a test tube
• The number of elodea plants in a test tube
• Light or dark
The set up for my control was:
Define the following from Chapter 5:
What is the importance of maintaining the same
chromosome number at the end of cell division?
What are the advantages and disadvantages of sexual and
asexual reproduction?
Cytokinesis –
Mitosis (purpose) –
Meiosis (purpose) –
Chromosome –
Study Guide Questions:
Pg. 43
Pg. 44
Pg. 45
Pg. 46
– do all
- #s 5, 6, 9, 12, & 13
- #s 1 & 3
- #s 5, the diagram, 7 & 8
24 November
What is Interphase?
What is happening during the Synthesis phase?
What is happening during prophase?
What is happening during metaphase?
What is happening during anaphase?
What is happening during telophase?
What is happening during cytokinesis?
* The cell cycle is a regular pattern of growth, DNA replication,
and cell division.
* The main stages of the cell cycle are gap 1, synthesis, gap 2, and
mitosis.
– Gap 1 (G1): cell growth and
normal functions
– DNA synthesis (S): copies
DNA
– Gap 2 (G2): additional
growth
– Mitosis (M): includes
division of the cell nucleus
(mitosis) and division of the
cell cytoplasm (cytokinesis)
• Mitosis occurs only if the cell is large enough and the DNA
undamaged.
https://www.youtube.com/watch?v=1cVZBV9tD-A
Mitosis
The object for today is to observe and draw the phases of mitosis.
Label the chromosomes and spindle fibers
Cytokinesis
30 November
• With your book and notebook closed, write all the components of the
cell cycle.
• What do you remember about each phase?
• What is the end result of mitosis?
* The cell cycle is a regular pattern of growth, DNA replication,
and cell division.
Define the following:
Diploid (2n) –
Haploid (n) –
Asexual reproduction –
Binary fission –
Centrioles –
Autosome –
Somatic cell –
Cancer –
https://www.youtube.com/watch?v=zglQ2Ildw4I
Diploid vs. haploid cells
Cell cycle and cancer
https://www.youtube.com/watch?v=AGEu88ujn5w
Cancer animation
https://www.youtube.com/watch?v=lpAa4TWjHQ4
1 December
DNA in Gap 1 of Interphase
DNA in Prophase
A sister chromatid refers to either of the two identical copies (chromatids) formed
by the replication of a single chromosome, with both copies joined together by a
common centromere.
The centromere is the part of a chromosome that links sister chromatids. During
mitosis, spindle fibers attach to the centromere
Parent cell
* Interphase prepares the
cell to divide.
centrioles
* During interphase, the
DNA is duplicated.
* Chromosomes condense
tightly for mitosis.
spindle fibers
centrosome
nucleus with
DNA
* Mitosis divides the cell’s nucleus in four phases.
– During prophase, chromosomes condense, the
nuclear envelope breaks down and spindle fibers
form.
* Mitosis divides the cell’s nucleus in four phases.
– During metaphase, chromosomes line up in the
middle of the cell.
* Mitosis divides the cell’s nucleus in four phases.
– During anaphase, sister chromatids separate to
opposite sides of the cell.
• Mitosis divides the cell’s nucleus in four phases.
– During telophase, the new nuclei form and
chromosomes begin to uncoil.
* Cytokinesis differs in animal and plant cells.
– In animal cells, the
membrane pinches
closed.
– In plant cells, a cell
plate forms.
Dec 3 and 4 were the field trip days to Spruce Creek Park
Students worked on questions from a packet that covered Mitosis and Meiosis
7 December
In the “Chapter 12: Cell Cycle” packet, please check to see if you
have completed the following questions.
1, 2, 4, 5, 6, 7, 8, 14, 15, 16, 17, 23, 27, 28, 30, 33, 42, 45, 46, & 47
Dr. Spence will discuss # 42, 45, & 46 on Wednesday
We will review these answers in 20 minutes
8 December
Goal for today is to understand
that genetic diversity is due to Prophase I of meiosis.
Define the following:
Crossing over –
Sex chromosomes –
Reduction division –
What is the end result of meiosis?
What are the advantages and disadvantages of sexual and
asexual reproduction. (make a table)
8 December
Study Guide Questions:
Please do these
Study Guide Questions: Pg. 53 – all questions
Pg. 54 – 9 – 15
Pg. 55 – all questions
Then page 48, the Concept Map and questions 10, 11, & 12
* Body cells are also called somatic cells.
* Somatic cells make up most body tissue and organs, not passed on to
offspring.
* Gametes (germ cells)
* located in the ovaries and testes.
* Gametes are sex cells: egg and sperm.
* Gametes are the cells that pass traits to offspring (children).
body cells
sex cells (sperm)
• Your body cells have 23 pairs
of chromosomes.
– Homologous pairs of
chromosomes have the
same structure.
– For each homologous pair,
one chromosome comes
from each parent.
• Chromosome pairs 1-22 are
autosomes. These contain
genes not directly related to
gender.
• Sex chromosomes, X and Y,
determine gender in mammals.
*Fertilization between egg and sperm occurs in sexual
reproduction.
*Diploid (2n) cells have two copies of every
chromosome.
*Body cells are diploid, and divide by mitosis.
*Half the chromosomes come from each parent.
How many chromosomes are present?
• Haploid (n) cells have one copy of every chromosome.
– Gametes are haploid, result from meiosis.
– Gametes have 22 autosomes and 1 sex chromosome.
How many chromosomes are present?
• Meiosis makes haploid cells from diploid cells.
– Meiosis occurs in sex cells.
– Meiosis produces gametes.
• Chromosome number must be maintained in animals.
• Many plants have more than two copies of each
chromosome.
• Mitosis and meiosis are types of nuclear division that
make different types of cells.
• Mitosis makes
more diploid cells.
10 December
Define the following:
Apoptosis –
Cancer –
Benign –
Malignant –
Metastasize –
Carcinogens –
Goal for today is to understand
what happens when cells grow out
of control.
• Apoptosis is programmed cell death.
* a normal feature of healthy organisms
* caused by a cell’s production of self-destructive enzymes
* occurs in
development
of infants
webbed fingers
KEY CONCEPT
Cell cycle regulation is necessary for healthy
growth.
* External factors include physical and chemical signals.
* Growth factors are proteins that stimulate cell division.
* Cell-to cell contact: most mammal cells form a single layer in a
culture dish and stop dividing once they touch other cells.
*Carcinogens are substances known to promote cancer.
• Standard cancer treatments typically kill both cancerous
and healthy cells.
* Cancer cells do not carry out necessary functions.
• Cancer cells come from normal cells with damage to
genes involved in cell-cycle regulation.
* Cancer cells form disorganized clumps called tumors.
– Benign tumors remain clustered and can be removed.
– Malignant tumors metastasize, or break away, and can
form more tumors.
normal cell
cancer cell
bloodstream
Begin review for Monday’s test.
The test will cover:
Photosynthesis
Respiration
cell cycle
mitosis
Meiosis
cancer.
Can you list the features unique to each
process in the table below?
Mitosis
Meiosis
Do you understand the difference between the
following reproductive strategies?
Asexual reproduction –
Binary fission –
Is it more advantageous for an organism to be
asexual?
* Asexual reproduction is the creation of offspring from a single
parent.
* Binary fission produces two daughter cells genetically identical to
the parent cell.
* Binary fission occurs in
parent cell
prokaryotes.
DNA
duplicates
cell begins
to divide
daughter
cells
* Fragmentation is the splitting of
the parent into pieces that each
grow into a new organism.
• Vegetative reproduction
forms a new plant from the
modification of a stem or
underground structure on
the parent plant.
1) What is the end result of mitosis?
2) What is the end result of meiosis?
3) What are homologous chromosomes?
4) What happens to the chromosomes during
Prophase I of meiosis?
5) What are the difference between plant and animal
mitosis?
http://www.ted.com/talks/spencer_wells_is_building_a_family_tree_for_al
l_humanity.html Spencer Wells
How big should cells be?
Why do cells occur in different sizes?
http://staff.fcps.net/cverdecc/Adv%20Biology/Note
s/The%20cell/ch5%20%20the%20cell%20notes.htm
* Too small: not enough space for organelles
* Too large: not enough material can move across surface
* Surface area must allow for adequate
exchange of materials.
– Cell growth is coordinated with
division.
– Cells that must be large have
unique shapes.
* The rate of cell division varies with the need for those
types of cells.
• Some cells will never divide, perpetual (G0).
* A chromosome is one long continuous thread of DNA.
* DNA wraps around proteins (histones) that condense it.
DNA double
helix
DNA and
histones
Chromatin
Supercoiled
DNA
* DNA plus proteins is called chromatin, which is formed during
interphase.
• One half of a duplicated
chromosome is a chromatid.
• Sister chromatids are held
together at the centromere.
centromere
Condensed, duplicated chromosome
Sister Chromatids