Good Morning Warm-Up: How do we grow?

http://www.youtube.com/watch?v=Q6ucKWIIFmg

How does our skin grow back after a cut?

Living things grow by producing more cells

Why don’t cells just grow larger??

Cells are most often microscopic. Do you think there is a limit to how big a cell can grow? Why? Fact- All cells require chemical energy and must release waste Fact-All cells have cell membranes AND all cells depend on passive transport to move materials into and out of cells…

Although an adult human is larger than an infant, the cells of both are the same size….therefore, there are just more cells in an adult!

Ch. 10 Section 1 Why Cells have a size limit

Two Reasons: 1. DNA Overload-the amount of DNA in a cell stays the same while the cell is growing +Too much demand on the DNA Think of the analogy of DNA as the books in a town library, and the cell size as the town size (population)

2nd Reason Surface area-to-volume ratio- Surface area increases at a slower rate than volume So when the cell is small, it absorbs less and expels less….meaning there’s less traffic = more efficient BUT…when the cell gets bigger, more things want to go through the cell membrane (food, oxygen, waste)

BUT…when the cell gets bigger, more things want to go through the cell membrane The cell membrane cant grow fast enough (surface area) so there are traffic problems Traffic causes the cell not to be able to get enough food and oxygen and cant expel wastes Much like you being sick, not being able to breathe through your nose or mouth, and having to go to the bathroom……Ahhhhhh!!!!

So a cell goes through cell division instead of growing larger.

Cell Division-one cell divides into two ‘daughter’ cells ---Cell Division via mitosis is a form of asexual reproduction

Asexual Reproduction-one cell makes two identical cells -Reproduction for many unicellular organisms -sources of new cells for growth & repair in multicellular organisms

Chromosomes carry DNA in eukaryotes. -consist of DNA and proteins Chromosomes carry DNA in eukaryotes -consist of DNA and proteins -chromatin condenses into chromosomes at start of mitosis

Replicated chromosomes have 2 identical sister chromatids attached at centromere

Cell Cycle The of events that cells go through as they grow and divide The cell cycle: a cell GROWS prepares for DIVISION DIVIDES into two identical daughter cells Those daughter cells then begins the cycle all over again

Cell Cycle

Interphase G1- where cells do most of their growing. Make new proteins and organelle S phase-DNA replicates G2- cell finishes making organelles

The Cell Cycle G1 phase, S phase, G2 phase Mitosis: PMAT Interphase: period of cell growth between divisions G1 phase, S phase, G2 phase Mitosis: PMAT Prophase, Metaphase, Anaphase, Telophase Cytokinesis

Mitosis Prophase- longest phase, chromosomes become visible. -centrioles move to opposite ends and begin to form spindles -spindles separate chromosomes by attaching to the centromere -nucleolus disappears and nuclear envelope breaks down

Metaphase:- chromosomes line up in the middle -spindles attach to centromere of each chromosome

Anaphase- Sister chromatids separate to become individual chromosomes -chromosomes move AWAY from each other

Telophase -chromosomes uncoil -2 nuclear envelopes begin to form -nucleolus becomes visible

Cytokinesis Cytoplasm is pinched to form two identical daughter cells ---cleavage furrow in animals, cell plate in plants

1/14/16: Warm-up #1 1. The two phases that make up the Cell Cycle are A.__________________ and B. __________________ 2. A._______________ is made up of 3 phases: a.___________ b.____________ and c. ____________ 3. B. _______________ is made up of Mitosis and _____________ 4. Mitosis is made up of 4 phases: a.____________ b.__________ c._____________ and d. ________________

What are the 3 processes that make up the Cell Cycle? Interphase, Mitosis, and Cytokinesis

What are the 3 phases of Interphase G1, S, G2

What are the phases of Mitosis? Prophase Metaphase Anaphase Telophase PMAT!!!!!

What happens in Cytokinesis? The cell splits into two identical daughter cells

What phase does the DNA replicate? The S phase of Interphase

When does the cell do most of its growing? During Interphase (specifically in G1)

What phase of Mitosis is this?

What phase of the cell cycle is this?

In what phase does the cell produce new organelles? Mostly in G1 but also in G2

In what phase do chromosomes become visible? Prophase

In what phase does the nuclear envelope break down? Prophase

A chromosome consists of what? Two identical sister chromatids

The two sister chromatids are held together in the center by a … Centromere

What is this?

What are the organelles that go to opposite ends of the cell during division to help separate the sister chromatids? Centrioles

Centrioles have microtubules called… Centrioles have microtubules called…..that attach to the centromeres to pull sister chromatids apart Spindles

The series of events a cell goes through in order to grow and divide is called….. The Cell Cycle

Reproduction A cell produces more cells by reproduction What is reproduction?

In a nutshell, reproduction is the creation of a new individual or individuals from previously existing individuals.

Asexual vs. Sexual Asexual-when a single parent reproduces by itself Sexual- when cells from two different parents unite to produce the first cell of a new organism

http://www.youtube.com/watch?v=VGV3fv-uZYI http://www.youtube.com/watch?v=ZEwddr9ho-4