Name: ____________________________________________
Date: ________________
Mitosis and meiosis Notes
Chapter 10: Cell Growth and Divison
Why are cells not larger?
• Cells are ____________ because:
1. DNA “_________________”: The larger a cell become, the greater the demand on its DNA; greater need of
the resource of DNA
2. Diffusion and osmosis are _____________
3. Surface area can’t keep up with __________________
• As cell increases in size, volume increases _____________ than the
surface area
How do we overcome this limit to cell size?
 If we can’t grow by having larger cells, then we must have
_____________ cells
 Cell division is the process by which a cell divides into two new
_______________ cells
 The cell begins by copying its DNA, each daughter cell gets ____________ copy
Cell Division
 Cell division in ___________________ is simpler and occurs by binary fission
◦ After DNA replication, cell ________________ are separated into two parts
 In eukaryotes cell division occurs by:
________________ – division of the nucleus
________________ – division of the cytoplasm
 Some organisms (especially unicellular) __________________ by mitosis and cytokinesis (asexual)
The Forms of DNA
 DNA is passed down from one generation to the next in the form of
_______________ (during anaphase and telophase) - precisely compacted chromatin
 Loose _________________ (during interphase) - threads of DNA & some protein
 Chromatids (during prophase and metaphase) – ______ of a duplicated chromosome
◦ _____________ chromatids separate from each other when the cell divides
Cell Cycle
1. _______________ – when the cell is not dividing, but doing its duty, and perhaps,
preparing for division
2. Mitosis:
 _______________ – centrioles separate, spindle forms,
paired chromatids, nuclear envelope is breaking apart
 ______________ – Sister chromatids align on the equator
 ______________ – Sister chromatids separate and
chromosomes move apart
 ______________ – Chromosomes concentrate at ends and
nuclear envelopes reform
3. Cytokinesis is the division of the _________________
 Typically occurs at the same time as _______________
 Animal cells: cell membrane _______________ off
Plant cells: ______________________ forms midway, gradually developing into a separating membrane
Cell Division Control
 Cell growth and cell division are ____________________ controlled
◦ Cells will grow into open space, but when cells ______________ other cells they respond by not growing
◦ Controls for cell growth (cell division) can be turned _______________________
◦ Similar effect occurs if you _________________ yourself
 _______________ – proteins that regulate the timing of the cell cycle
 Many other proteins involved in regulating the cell cycle including internal and external regulators
 Cancer – _________________ cell division. Cancer cells do not respond to the signals that regulate the growth
of most cells
 Causes of cancer:
1. ____________________ (smoking, UV radiation, viruses…)
2. ________________ (many have a defect in gene p53 which stops the cell cycle until all chromosomes have
been properly replicated
Cancer Treatments
 There is no ___________ for cancer, and there probably never will be
 However, there are a number of current and future cancer _________________
◦ Radiation therapy- ionizing radiation designed to kill cancer cells; _________________ cancer and
healthy cells
◦ Chemotherapy- ____________ that destroy cancer cells; traditionally affect all rapidly dividing cells
◦ _______________- cut out the cancer cells; is not possible for all cancers
◦ Other treatments- angiogenesis inhibitors, targeted therapies, __________________, electroporation,
◦ ____________________________
Chapter 11: Introduction to Genetics
DNA and Sexual Reproduction
 Why do many organisms combine _________ from two parents to make offspring?
 How does a sperm and egg (gametes) _________________ to form 1 cell with appropriate amount of DNA?
◦ If two normal human cells combined to form the new embryo, how much DNA would the embryo have?
◦ How would you overcome this problem?
Chromosome Number
 Humans have _____________ of 23 chromosomes (46 total)
◦ 1 ________ comes from the female, the other from the male parent
◦ The sets are called ________________ chromosomes which code for the same trait but are different
A cell that has both sets of homologous chromosomes is called _____________ (2 sets)
A cell (gametes) that only contain 1 set of chromosomes is called ____________ (1 set)
 Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in _________
through the separation of homologous in a diploid cell
◦ Has two distinct sections: ________________________________
◦ At the end of Meiosis II, 1 diploid cell has become ____________________ cells
Meiosis I
 Prior to Meiosis I each chromosome is _______________ (like mitosis)
◦ Meiosis I is similar to _______________
◦ Difference is that in prophase I each chromosome pairs with its corresponding
homologous chromosome to form a ______________
◦ As a result, ________________ occurs which results in exchanging portions of
their chromatids
Meiosis II
 After Meiosis I, the two cells enter a _________________ meiotic division (no
replication beforehand)
◦ Prophase II, Metaphase II, Anaphase II, Telophase II/ Cytokinesis
◦ Cell now only have _________ the standard DNA (chromosomes) – haploid
◦ Each of the 4 cells created are ____________ (genetically different)
 For males the cell created become sperm, in females an egg (both are ________________)

Mitosis and meiosis notes