Download Cell Reproduction Notes

MITOSIS AND MEIOSIS—CHAPTER 10 & 11-4
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Why don’t cells get bigger forever??
Let’s do a lab!
– With some math!
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Surface area =___________________
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Volume = l x w x h
Calculations
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Cell 1
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Sides: .5 cm
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SA=
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Volume =
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When cut…
Cell 2
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Sides: 1 cm
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SA=
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Volume =
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When cut…
Cell 3
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Sides: 2 cm
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SA=
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Volume =
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When cut…
Limits to cell growth
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The ______________ a cell becomes, the ______________________ the cell places on its DNA.
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In addition, the cell has more trouble moving enough ____________________ and __________
across its cell membrane
– Activity
Surface Area to volume ratio
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We want surface area to be bigger then volume
– WHY? (Think about the lab)
So how do cells solve this problem?
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Before they get too large…
– They ___________________!
– Into two _______________________ cells
– Called CELL DIVISION
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What steps may be involved?
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Two stages
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Stage 1: MITOSIS
– Dividing _______________________
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Stage 2: CYTOKINESIS
– Dividing __________________________
Chromosome
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We have ________!
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_______________________________ DNA
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In mitosis, each chromosome gets ____________________
– Now called two _________________________________ held together by a centromere
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Sketch it out!
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The Cell Cycle
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Series of events that cells go through as they _____________________________
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Grows, prepares to divide, and divides
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Two main parts
– _____________________
– ______________________
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Divided into 2 parts
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Interphase
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G1 - “_______________” - Cell ________________ from last cell cycle
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S – _____________________ of DNA (DNA makes a copy of itself)
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G2 – Cell ______________ and _________________ for cell division
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G0 – __________________________ – typical of cells like nerve cells that stop dividing at
maturity
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Mitosis – M phase
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___rophase
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___etaphase
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___naphase
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___elophase
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Cytokinesis
Interphase
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_____________________________ in the Cell Cycle
– over half the time is spent in this phase
Mitosis
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Prophase (Preparation)
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_______________ phase in __________________
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Copied chromosomes ________ up. Held together by Centromere (each is called a chromatid)
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Shortening up of chromosomes, makes them ____________________
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Replicated Centrioles (of animal cells______________________________________________
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Nuclear envelope & nucleolus start to _________________________________
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Spindle fibers (microtubules) _______________________________________ to centromeres
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Metaphase
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____________________ part of Mitosis
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Chromosomes ____________ on the equator (__________)
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Anaphase
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“_______________________________________”
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Chromatids _________________ and go to opposite poles. Now
called ________________________________!!
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Spindle fibers _________________________________
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Telophase
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“_________________________” – Final phase
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Chromosomes reach opposite _______________
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Cell membrane pinches in (__________________________)
or ______________________ forms (if plants)
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Chromosomes _______________________
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Nuclear membrane & nucleolus __________________
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Spindle fibers ____________________________
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Cytokinesis
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Dividing ______________________________. Occurs simultaneously with Telophase
MITOSIS OVERVIEW
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Difference between Plant and Animal mitosis
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___________________________ in plant cells
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A ________________________ forms in plant cells
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Animal cells have a ___________________________________ that splits the two cells
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How do cells…
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Know when to grow?
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Found important factors
– __________________ prevents growing
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Cyclin is a protein that regulates the timing of the cell cycle.
– Amount of ________________________ in a cell rises and falls with the steps in the cell cycle.
– There are other internal and external _________________ that are also involved the cell cycle.
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Cancer
– ______________________________________________.
– Cells do not respond to normal signals and grow ___________________________________.
o Cause masses called _____________________.
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Count those chromosomes
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We have _____________
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If we made a baby, how many would they have?
– 46 from mom
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– 46 from dad
+ _____
– 92 for baby
– No longer human!!
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What do we do?
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We go through MEIOSIS
– Process that takes our ___________________ of chromosomes (__________ number{2N})
and cuts them into __________________(_____________ number{1N})
– 46______
– 23 from mom + 23 from dad = _____!
• Normal baby!
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Meiosis Steps
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Unlike mitosis, meiosis has ______________________ of division
– Meiosis ___
– Meiosis ___
Meiosis I:
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Interphase I:
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Replication of chromosomes. Like chromosomes are called _________________________
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Prophase I:
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The homologous chromosomes _______________________________ (Synapsis) and
form a group of 4 called a _______________________.
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Twisting & exchange parts of adjacent chromatids will occur – ______________________.
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This results in _________________________________ and unlinks genes that are located
on the same chromosome.
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HUGE GENETIC VARIETY!!!!!
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Anaphase I & Telophase I
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Chromosomes _________________ independently of each other.
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This is known as Independent assortment.
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Results in…
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_________________________________ of chromosomes
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Genetic recombination!!!!!
At the end of Meiosis I, there are
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______________________
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Meiosis II
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Occurs immediately following Telophase I.
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NO _______________________________ !!
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1N cells immediately go into _____________ II, then Metaphase II, Anaphase II, and Telophase II
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Split into _________________________________, each with unpaired chromosomes
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____________________________
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Gametogenesis
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Creation of ___________________________ (sex cells)
Spermatogenesis (_______________________)
– Makes ________________________ from 1 - 2N primary sperm cell. Looks like normal Meiosis
Oogenesis (____________________)
– Produces ovum (eggs) from 1 diploid primary egg cell. Difference occurs during
_______________________ during meiosis I and meiosis II.
– __________________________________ of the cytoplasm resulting in _____ large ovum and
_____ small polar bodies.
• Polar bodies serve __________________ in animals but are needed in to plant embryos.
Comparing Mitosis and Meiosis
• Be sure to know…
– How many divisions for each?
– How many starting cells?
– How many cells at the end?
– What N are those cells?