Bio 5.2

Biology 5.2

Mitosis & Cytokinesis​

By ALEJANDRA MENDOZA

​II. Mitosis and Cytokinesis (5.2)

A. Chromosomes condense at start of mitosis

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1. Chromosome- one long continuous thread of DNA

   a. consists of numerous genes

   b. you have 46 chromosomes​

​c. Must be condensed to fit into cell nucleus

1. DNA wraps around proteins called histones

2. when loosely condensed called chromatin​

Multiple Choice

What do chromosomes do at the start of mitosis?

• grow

• condense

• disappear

• divide

Multiple Choice

How many chromosomes do we have?

• 46

• 48

• 45

• 44

​d. Chromosomes looks like "X" (each half is identical DNA- called a chromatid)

​​

e. Sister chromatids held together by centrome​re

​f. Telomeres- found at ends of DNA molecules and prevent DNA from coming apart

Multiple Choice

What do chromosomes look like?

• x

• y

• z

• a

B. Mitosis and cytokinesis prod​uce two genetically identical daughter cells

1. Interphase- important role in preparing cell to divide (2

sets of DNA and are large enough)​

2. Mitosis- divides cell's nucleus into two genetically

identical nuclei, each with its own single full set of DNA​

Multiple Choice

What do mitosis and cytokinesis produce?

• two genetically identical nuclei

• two different nuclei

• two polar identical nuclei

• two colorful nuclei

​3. 4 main phases of Mitosis

a. Prophase- DNA condenses into tightly coiled chromosomes. Nuclear envelope breaks down. Centrioles move to poles and spindle fibers form​

​b. Metaphase- Spindle fibers attach to each chromosome. Chromosomes align along cell equator (middle)

​c. Anaphase- chromatids separate to opposite sides of cells

​d. Telophase- nuclear membrane starts to form chromosomes begin to uncoil and spindle fibers fall apart

Multiple Choice

What happens during anapahse?

• Chromatids separate

• Chromatids attach

• Chromatids stick

• Chromatids run

​4. Cytokinesis - division of cytoplasm. different animal and plant cells

Multiple Choice

What happens during cytokinesis?

• cytoplasm creation

• plant cells grow

• division of cytoplasm

• animal cells grow