Which of the following is an example of a haploid cell? 1. Stomach cell 2. Brain cell 3. Sperm Cell 4. Skin cell

How many chromosomes are in your Somatic (body)cells?

Your somatic (body) cells have how many pairs of homologous chromosomes? pairs pairs pairs 4. 2 pairs 10 Response Counter

This is a picture of 1. Gamete 2. Chromatin 3. Duplicated chromosome 4. Karyotype 10 Response Counter

Human somatic cells contain _____ pair(s) of sex chromosomes. A. 22 B. 1 C. 23 D

Gametes are _________, meaning they contain one set of chromosomes. A. Diploid B. Haploid C. Triploid D. Monoploid 30

If an organism contains 14 chromosomes in each somatic cell, then its gametes each contain ____ chromosomes. A. 7 B. 14 C. 21 D

What is #1 in the picture? 1. Centromere 2. Centriole 3. Sister Chromatid 4. Chromatin 10 Response Counter

What is #2 in the picture? 1. Centromere 2. Chromosome 3. DNA 4. Chromatin 10 Response Counter

The Cell Cycle PARTS OF THE CELL CYCLE 1.Interphase G1 S G2 2.Mitosis Prophase Metaphase Anaphase Telophase 3.Cytokinesis

Interphase 90% of cell life cycle  cell doing its “everyday job”  prepares for duplication if triggered Characteristics  nucleus well-defined  DNA loosely packed in long chromatin fibers

Interphase  G 1 – First stage after division Cell increases in size Doubles organelles Cells do everyday job

Interphase S – DNA synthesis occurs  DNA Replication takes place in the nucleus (copies chromosomes) G 2 – Growth & final preparations for division  Prepares for division  Proteins that aid in mitosis are made in this stage  Microtubules

Control of the Cell Apoptosis – Programmed cell death  Apoptosis & the cell cycle work together to maintain # of cells in the body (Homeostasis) Cell Checkpoints (Each controlled by proteins)  G 1 – Checks DNA for mutations after G 1  If ok the cell cycle goes on, if not… APOPTOSIS!  G 2 – Check to make sure DNA has been copied correctly  if DNA replicated correctly process moves to mitosis, if not… APOPTOSIS!  M Checkpoint – Checkpoint in mitosis/Checks that chromosomes are attached to spindle  Takes place between metaphase and anaphase  Ensures chromosomes have lined up correctly, if not…. APOPTOSIS!

Cancer Uncontrolled cell growth Why?? Checkpoints in cell cycle break down  Due to mutations in genes that produce proteins that control the checkpoints  Can cause tumors (mass of cells)  Malignant tumor – cancerous tumor that may spread to other areas of the body  Benign tumor – non-cancerous tumor  Biopsy- sample tissue is taken from tumor to determine if it is cancerous or not  Metastasis- the spreading of cancer from one part of the body to another

What is the DNA/protein complex called? (Hint: This is DNA when it is unwound) 1. Chromosomes 2. Chromatin 3. Chromatids 4. Centromere

In which stage of interphase does the cell replicate its DNA? 1. G1 2. G2 3. S

Programmed cell death is called 1. Mitosis 2. Cancer 3. Apoptosis 4. G0

Cell growth and final preparation for division occurs at which stage of interphase? 1. G1 2. S 3. G2

What is a chromosome? DNA is packaged into chromosomes. Chromosomes are threadlike structures of DNA wrapped around proteins. CHROMATIN – DNA tightly coiled around histone proteins CHROMOSO ME

Eukaryotic Chromosome Structure Chromosomes are only visible when a cell is dividing so we usually see them in their double-stranded form.

Eukaryotic Chromosome Structure The halves of a double-stranded chromosome ( sister chromatids) are identical to each other because the DNA (original chromosome) replicated before cell division. (part of chromosome where the two chromatids attach)

Why are chromosomes important in cell division? Chromosomes make it possible to separate DNA precisely. Each new cell will get the exact same DNA as the cell it came from.  DNA Replication takes place before cell division!

Prokaryotic Chromosome Structure Where is the nucleus?  THERE IS NO NUCLEUS! IT’S A PROKARYOTIC CELL! ONLY EUKARYOTIC CELLS HAVE A NUCLEUS!

Types of Cells There are two types of human cells: somatic cells and gametes.  Somatic Cells = body cells (brain, muscle, heart, liver, skin, etc)  Contain 46 chromosomes in humans  Diploid (2n)= cell that contains two sets of homologous chromosomes  Gametes = sex cells (sperm or egg)  Contain 23 chromosomes in humans  Haploid (n)= cell that contains one set of chromosomes

The Cell Cycle 1.Interphase 1.G1 2.S 3.G2 2.Mitosis (PMAT) 3. Cytokinesis

Mitosis – division of the nucleus 4 Parts (PMAT): Prophase, Metaphase, Anaphase, Telophase

Prophase Chromatin (DNA) condenses into chromosomes Centrioles move to opposite poles of cell Microtubules extend from the centrioles to form mitotic spindle  Pull apart sister chromatids Nucleolus disappears Nuclear membrane breaks down Chromosomes attach to spindle fibers Pro = Prepare

Metaphase Spindle fibers align chromosomes along the middle of cell  Meta = Middle  metaphase plate  helps to ensure chromosomes separate properly  so each new nucleus receives only 1 copy of each chromosome

Anaphase Sister chromatids separate  move to opposite poles  pulled at centromeres  Ana = APART

Telophase Opposite of prophase The chromosomes are at the poles of the spindle. The spindle fibers disintegrate The nuclear membrane re-forms around the two sets of chromosomes. Chromosomes uncoil to become chromatin again Telophase = looks like a Telephone or makes Two nuclei.

Cytokinesis Cell divides into two identical daughter cells Plant and animal cells divide the cytoplasm in different ways.

Cytokinesis (Plants) In plant cells, a new cell wall made of cellulose forms between the 2 new nuclei called the cell plate. When the new wall joins with the existing side wall, the 2 cells have become separate.

Cytokinesis (Animals) In animal cells, a ring of protein fibers forms around the cell equator and contacts, pinching the cell in half.