Name:____________________________
Study Guide: Mitosis and Meiosis
Date:_______________
A. Review Genetic Engineering Study Guide
B. Mitosis
a. Why do cells divide?
i. Grow too large1. can’t get nutrients in fast enough, can’t get waste out fast enough to meet with
material requirements
2. can’t make copies of DNA or RNA fast enough to keep up with informational
requirements
ii. Surface Area to Volume ration becomes small so that the cell is stressed
b. When do cells divide?
i. To grow, to Repair, to Reproduce
c. Forms of DNA
i. Chromatin- relaxed DNA; long and stringy
(during Interphase)
ii. Chromosomes- condensed (coiled) DNA;
can be seen during mitosis
iii. Sister Chromatids- a chromosome that has
replicated itself forms 2 identical sister
chromatids that are attached by a centromere
d. Stages of the Cell Cycle
i. G1 → S → G2 → M → C
ii. Interphase: “resting,” but not quite (stage where cells spend most of their time)
1. G1 – Growth and Life Processes
2. S – DNA Replication
3. G2- Prepare for Mitosis (Microtubules form)
Name:____________________________
Study Guide: Mitosis and Meiosis
Date:_______________
iii. Mitosis: Cell Division
1. Prophase – “1”
a. Visible Chromosomes (condensed)
b. Nuclear membrane disappears
c. Nucleolus disappears
d. Centrioles at the poles
2. Metaphase- “middle”
a. Chromosomes line up in the
middle of the cell
b. Very short
3. Anaphase- “away/apart”
a. Sister chromatids separate and migrate
to the poles traveling along spindle fibers
4. Telophase – “2”
a. Sister chromatids regroup at opposite poles
b. 2 nuclei form
c. Nuclear membrane forms, centrioles reappear
5. Cytokinesis
a. 2 cells form
i. Animal Cell – pinching cell membrane
ii. Plant cell – cell plate (wall) forms
e. Types of Mitosis (ALL RESULT IN IDENTICAL OFFSPRING)
i. Binary Fission- Cell divides into 2 equal sized cells (ameba and paramecia)
ii. Budding – “buddy” cell divides into 2 unequal sized cells (hydra, yeast)
iii. Spore formation – make many spores which can each become new organism (bread
mold)
iv. Regeneration – new individual, or part, after a piece is removed (starfish, worms, hydra)
v. Vegetative Propagation- asexual reproduction in plants
1. Natural – Bulbs, tubers, corms, runners
Name:____________________________
Date:_______________
Study Guide: Mitosis and Meiosis
2. Artificial- cutting, layering, grafting
f. Abnormal cell division
i. Cancer – abnormal, uncontrolled cell growth and division. Kills an organism by
crowding out healthy cells. Spend less time than normal in interphase, go immediately
into mitosis (cell cycle is broken down)
ii. Tumor- mass of cells
iii. Malignant tumor- tumor that invades and destroys other healthy tissue preventing those
tissues from functioning properly
iv. Causes of Cancer
1. Carcinogen- cancer causing substance
2. Gene mutation (defect in p53)
3. Radiation and UV light
4. Viruses
v. Treatment
1. Surgery for removal
2. Carefully targeted beams of radiation
3. Chemotherapy (chemical) – produce many serious side effects
C. Meiosis: Cell division to make new SEX CELLS
a. Gametogenesis: making of sex cells; Only happens when an organism reaches sexual maturity
(humans – puberty)
b. Sex Cells – n chromosomes (haploid = monoploid) – only one of each homologous
chromosomes
c. Fertilization: egg (n) + sperm (n) → zygote (2n)
In humans: in the Fallopian Tubes
i. An egg only lets one sperm enter! It changes its permeability to make sure that only one
sperm enters so that the zygote will only have 2n chromosomes!
Name:____________________________
Study Guide: Mitosis and Meiosis
Date:_______________
d. Diploid – (2n) full number of chromosomes; (Humans = 46 total chromosomes)
e. Homologous pairs – pairs of chromosomes that are the same size, same shape, code for the same
traits that you get from Mom and Dad (Human body (somatic) cells = 23 pairs of homologous
chromosomes)
f. Haploid or Monoploid – (n) half the number of chromosomes; only one of each homologous
chromosome (Human sex cells = 23 chromosomes)
g. Gamete – sex cells
h. Spermatogenesis: making sperm
i. Begins at puberty, ends at death
i. Oogenesis: making egg
i. Begins at puberty, ends at Menopause – when a woman stops menstruating and making
eggs
j. Tetrad- Four chromosomes that come together during the first meiotic division (replicated
homologous chromosomes)
k. Crossing Over- noteworthy event of meiosis; occurs during prophase; Homologous
chromosomes line up, replicate, form a tetrad, come together (synapsis) and exchange parts of
their DNA; causes the resulting cells to all be different from one another. VARIETY in
SPECIES enhances survival!
l. Disjunction- During the first meiotic division (metaphase) the homologous chromosomes line up
in pairs and separate into opposite cells, so each cell only gets one of the homologous
chromosomes
Name:____________________________
Date:_______________
Study Guide: Mitosis and Meiosis
m. Nondisjunction – if the homologous chromosomes don’t separate, one sex cell winds up with 2
of the homologous chromosomes (not good!) and the other winds up with none (not good!)
i. Down’s syndrome: nondisjunction of chromosome #21
n. Identical twins vs. Fraternal Twins
How does the DNA of identical twins compare to the DNA of fraternal twins? Can a
boy and girl be identical twins?
o. Stages of Development: Meiosis (Sex cells) → Fertilization → Cleavage → Morula → Blastula
→ Gastrula → growth and specialization (differentiation) → Birth
Name:____________________________
Study Guide: Mitosis and Meiosis
Date:_______________
*How would you identify each of the following types of vegetative propagation? Give an example of a plant
that undergoes each? Is this asexual reproduction or sexual reproduction? Why?
*Identify the types of asexual reproduction in the pictures below. How are they similar? How are they
different?
*Explain the processes of mitosis
And meiosis. How are they similar?
How are they different?
Make sure you can identify and explain the
Following stages of the cell cycle:
Interphase, Prophase, Metaphase,
Anaphase, Telophase, Cytokinesis in
Both plants and animals.