 Friday, April 24, 2015 Opener: How does cellular respiration connect to mitosis – the making of new cells??? By the end of class today, I should be able to: 1. Summarize the cell cycle and 2. Identify the phases of cell division

Agenda  Change seats  Mitosis- cell division lecture & activity

Question:  How would the gene you put into your genetically engineered organism get passed on? What if you had “gene therapy”. Would the new genes be passed to your children?  Where does DNA “live”?  How do cells pass along their DNA?

How do cells replicate?  They divide … and divide …and divide……

Where it all began… You started as a cell smaller than a period at the end of a sentence…

And now look at you!!

Human Life Cycle The Human Life Cycle Can you identify each phase?

Mitosis 1. Mitosis-when one cell divides into two cells which are identical

Dividing cells…  What has to be copied  DNA  organelles  cell membrane  lots of other molecules  enzymes animal cellplant cell

Chromatin 3.Normal, non-dividing cells (During G 1 and S phase) have their DNA loosely packed into________________ This helps cells do their job and allow genes to be transcribed/translated into proteins._ chromatin

The Problem (in eukaryotes)? If chromosomes (DNA molecules) were like pasta, which would be easier to pull apart into individual pieces A plate of tangled spaghetti Or a plate of macaroni? Eukaryotic DNA

Copying DNA  Matching bases allows DNA to be easily copied

Making new DNA  Copying DNA  replication  DNA starts as a double-stranded molecule  matching bases (A:T, C:G)  then it unzips…

DNA replication  Strands “unzip” at the weak bonds between bases

DNA replication  Enzyme  DNA polymerase  adds new bases DNA polymerase DNA bases in nucleus

DNA Polymerase Copying DNA  Build daughter DNA strand  use original parent strand as “template”  add new matching bases  synthesis enzyme = DNA polymerase

New copies of DNA  Get 2 exact copies of DNA to split between new cells DNA polymerase DNA polymerase

Copied & Paired Up Chromosomes centromere

Chromosomes 9. The ____________________ are identical strands of DNA. 8. Label the structure of a chromosome chromatids 10.Human cells have ______ chromosomes 46 7.It’s not until Prophase of mitosis that the chromatin forms into the familiar “X” shaped ________________ chromosome Holds chromatids together

Chromosomes of Human Female 46 chromosomes 23 pairs

double-stranded human chromosomes ready for mitosis 1 molecule of DNA Identical molecule of DNA Together they are called “Sister chromatids”

Cell Cycle S phase G 1 phase This is where cells spend most of their time G 2 phase DNA is Synthesized (replicated) – S phase S phase M phase Mitosis! Cell Grows after mitosis What triggers a cell to divide? A chemical signal that let’s the cell know a new cell is needed. S phase begins Cell Growth Checkpoint : enzyme edits DNA and fixes mistakes. Can’t fix? Cell death.

Please Make Another Two Cells DNA (chromatin) winds up into chromosomes Nuclear envelope (wall) breaks down Chromosomes line up across center of cell & attach to spindle fibers (little cables made of protein). Chromatids separate into individual chromosomes Chromosomes gather at opposite ends of cell. Unwind Two nuclear envelopes form The cell pinches in half Two daughter cells form, each with identical set of chromosomes Interphase DNA copied! Copy! Wind up! Line up! Separate! Bye bye!

Big idea: 1 cell makes two identical “daughter” cells  Get 2 exact copies of original cells  same DNA  “clones”

Cell division in Animals

Hollywood does Mitosis

Mitosis in whitefish embryo

What happens if cell cycle goes wrong? Cancer Unregulated mitosis  Benign  Malignant/ metastasis  How does it begin?

Overview of mitosis interphaseprophase metaphaseanaphasetelophase cytokinesis I.P.M.A.T.C. P lease M ake A nother T wo C ells

 Answer these questions on the bottom of page 4. What types of human cells do NOT divide? What types of cells divide the fastest? (bio textbook page 249) Exit Ticket

What does mitosis look like?

Making a mitosis flipbook.

 For a stamp (#9)  Use a corner of your science journal  Go from the back of the journal to the front  10 pages per phase  Colored pencils for each phase Making a mitosis flipbook.

 Use a corner of your science journal  Go from the back of the journal to the front  10 pages per phase  Colored pencils for each phase  An example of a short animationexample of a short animation Making a mitosis flipbook.