Which of the following is an example of a haploid cell? Stomach cell Brain cell Sperm Cell Skin cell 0 of 0 7

How many chromosomes are in your Somatic (body)cells? 23 32 64 46 0 of 20 1

Your somatic (body) cells have how many pairs of homologous chromosomes? 1

This is a picture of Gamete Chromatin Duplicated chromosome Karyotype 1

Human somatic cells contain _____ pair(s) of sex chromosomes. 22 1 23 46 1

Gametes are _________, meaning they contain one set of chromosomes. Diploid Haploid Triploid Monoploid 27

If an organism contains 14 chromosomes in each somatic cell, then its gametes each contain ____ chromosomes. 7 14 21 28 14

What is #1 in the picture? Centromere Centriole Chromatid Chromatin 10 0 of 21 10

What is #2 in the picture? Centromere Chromosome DNA Chromatin 9 0 of 21 9

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

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

Interphase G1 – First stage after division Cell increases in size Doubles organelles Cells do everyday job 9.1

Interphase S – DNA synthesis occurs DNA Replication takes place in the nucleus (copies chromosomes) At the end of S phase, each chromosome contains two identical strands of DNA (sister chromatids) G2 – Growth & final preparations for division Prepares for division Proteins that aid in mitosis are made in this stage Microtubules 9.1

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) G1 – Checks DNA for mutations after G1 If ok the cell cycle goes on, if not… APOPTOSIS! G2 – 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! 9.1

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 Metastasis- the spreading of cancer from one part of the body to another

Chromosomes Chromatin Chromatids Centromere What is the DNA/protein complex called? (Hint: This is DNA when it is unwound) Chromosomes Chromatin Chromatids Centromere 0 of 21 1

In which stage of interphase does the cell replicate its DNA? 4

Programmed cell death is called Mitosis Cancer Apoptosis G0 0 of 21 2

Cell growth and final preparation for division occurs at which stage of interphase? 1

The Cell Cycle Interphase G1 S G2 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

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, about where the chromosomes lined up in metaphase. Cell membranes form along the surfaces of this wall. 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.