Name: ___________________________ Date: ______

Cell Division (Asexual and Sexual Reproduction)Cell Cycle

Why can’t we all be just one big cell?o A cell that is too ______ puts too ______ of a demand on its organelles

How do cells solve this problem? o __________________________________________________________o This is called the ________________ __________________

Do cells spend all of their time dividing? ___________________

Cell Life Cycle

1.

_____________________: during this stage, the cell grows and replicates its DNA. There are ___________ parts of this stage.

a. _______________: cell grows a lotb. _______________: (aka Synthesis phase) this is where DNA replicates (copies)c. _______________: cell grows some more

2. ______________________: this is when the nucleus divides3. ______________________: this is when the cytoplasm and the rest of the cell divides into two cells

a. _______________: don’t have a cell wall, so they just pinch off from each other b. _______________: have a cell wall so they can’t pinch off from one another. Instead,

___________________ forms between the two new cells

Cancer: ______________________________________ __________________: a group of cells that are dividing uncontrollably

__________________: proteins that regulate or control the cell cycle

Chromosomes before a cell can divide, it must __________ its DNA (________ phase of the cell cycle) In Eukaryotes, DNA is packaged into ______________________ During replication, each ______________________ becomes a _____________

________________________ Chromosomes have a little ball in their center called a _______________________.

**Don’t get confused! A double chromosome is still considered to be one chromosome even though it has two sides. An easy way to determine how many chromosomes a cell has is to count the centromeres.

Label the picture below with the words double chromosome, single chromosome, and centromere. You will use the word centromere twice. (also note the sister chromatids)

The cells below have the same number of chromosomes. How many chromosomes do they have? __________

Which cell above has replicated its DNA and so has double chromosomes instead of single chromosomes?____

Mitosis: ________________________________________ What types of cells undergo mitosis? _________________________________________________ Products of mitosis: _______________________________________________________________ What is mitosis used for? ___________________________________________________________

MITOSIS

akes w

o cells

ame

We call the original cell the “parent cell” and the two cells produced through mitosis the “daughter cells.”

Stages of Mitosis:

1. _____________________ : nucleus dissolves and DNA is packed into chromosomes

a. What did DNA look like before? _______________________b. Why do the chromosomes look like X’s? ________________

2. _____________________: double chromosomes like up in the middle of the cell a. ___________________: are in animal cells and move to opposite sidesb. ___________________: long spiderweb like strings that pull the sister

chromatids ___________

3. _____________________: the sister chromatids of the double chromosomes split apart and begin moving away from one another.

4. _____________________: single chromosomes move to opposite ends of the cell, nucleus reforms, and the cell beings to pinch apart

Products of Mitosis: __________________________ cells are produced ___________________________ because parent and daughter cells

are the same Why do the parent cells have _____________ chromosomes and the

daughters only have _____________ chromosomes? __________________________________

Diploid vs. Haploid Cells: _____________________ (_____) cells that have 2 sets of chromosomes

(one from mom and one from dad)

_____________________ (_____) cells have only one set of chromosomes

Mitosis starts with a ____________ parent cell and ends with _________ daughter cells

Meiosis: ________________________________________

What types of cells undergo meiosis? _________________________________________________ What is meiosis used for? ___________________________________________________________ ___________________ : a sperm or an egg cell Meiosis begins with a ______________ parent cell and ends with ________ ___________ ______ Gametes need to have ________ of the DNA (__________) so that when the sperm and the egg join, the

organism will be __________ .

Stages of Meiosis

New Meiosis Vocabulary ______________________________________ : chromosomes that code for the same genes (ex.

chromosome #3 from mom and chromosome #3 from dad) _______________________________________: 4 chromatids that have the same genes on them

(double chromosome from mom and double chromosome from dad) _______________________________________: happens when tetrads are formed during prophase I

Human Life Cycle:

-Meiosis-Fertilization-Mitosis & Development

Sources of Genetic Variation

Why don’t all offspring from the same parents look identical? _________________________________________

Sources of Variation:1. _______________________________: when homologous chromosomes exchange parts of chromatids

during meiosis2. _________________________________________: independent segregation of genes during the

formation of gametes3. _________________________________________: random chance of a specific sperm pairing with a

specific egg4. _________________________________________: changes in the DNA sequence

Variation:___________________________________ Variation: _______________________________

Variation:___________________________________ Variation: _________________________

Asexual vs. Sexual Reproduction

What type of cell division is asexual? ________________________o Why is this a good thing? _________________________________________________________

What type of cell division makes sexual reproduction possible? _____________________________o Why is this a good thing? _________________________________________________________

Fill in the table, by putting check marks in the appropriate blanks: Sexual Reproduction Asexual Reproduction

Requires 2 individualsRequires 1 parentResults in genetic variationKeeps genes the same (no variation)Quicker, like mitosisUsed by simpler animals Egg and sperm produced by meiosis

Give one advantage and one disadvantage of sexual reproduction:

Give one advantage and one disadvantage of asexual reproduction:

Modes of Sexual Reproduction ___________________ Fertilization ___________________ Fertilization

Modes of Asexual Reproduction: ___________________: part of a parent pinches off to form a new offspring ___________________: a broken part will grow back ___________________: a new organism grows from a fragment of the parent ___________________: where one cell divides into 2 separate but genetically identical cells (bacteria use

this)