bio Ch 9

Bio Ch. 9

Abnormal cell cycle

- Cancer occurs when quality control fails

- Uncontrolled cell growth and replication occurs

- Cancer crowds out normal cells, resulting in loss of tissue function

- Can occur in weak or healthy cells

- Due to mutation in DNA

- Avoiding carcinogens can help reduce cancer

- Avoiding UV and other radiations can help reduce it as well

Normal Cell Cycle

- Timing and rate of cell division are important

- Cell division is started by cyclin and cyclin-dependent kinases (CDK)

- In G1, cyclin combines with CDK to signal the start of the cell cycle

- Different cyclins combine in different ways to do different things

- Cell cycle has checkpoints to stop if something goes wrong (Fig 11 page 253)

Cancer Cont.

- More than 1 change in DNA is necessary for cancer to happen

- Over time, many changes can occur in DNA

- Risk of cancer increases with age

Homework: Pages 261-263, 1-27

Section 3 Assessment

What is Apoptosis?

Compare and Contrast Normal Cells and Cancer Cells

Apoptosis

The Cell Cycle

Stem Cell Research: Should we use it?

Research pros and cons of both types of stem cell research. What types of experiments use stem cells? From a Christian view point, should we use stem cells?

- Programmed cell death

- Shrink and shrivel in a controlled process

- Example: Fingers and toes are webbed in development

- Cells between fingers and toes undergo apoptosis

- Used to help protect against cancer

Stem Cells

- Cells eventually divide

- Cells reproduce by the cell cycle

- Three main stages: Interphase, Mitosis, Cytokinesis

- Interphase: Cell grows and carries out cellular functions

- Mitosis: Cell's nucleus and nuclear material divide

- Cytokinesis: Cytoplasm divies

- unspecialized ells that can develop into specialized cells under the right conditions

- Two basic types: embryonic and adult

- Embryonic: First cells that form after a sperm fertilizes an egg

- Scientists can use to grow organs and tissues

- Use is controversial

Adult Stem Cells

Mini Lab 1

Cell Size Limitations

- Found in various tissues in the body

- Found in various tissues in the body

- Can be used to develop into different kinds of cells to treat diseases and conditions

- Most cells are less than 100 micrometers in diameter

- Ratio of surface area to volume limits the size of the cell

- Figure 1 Page 244

- Small cell allows for easier transport of substances

- Small cell allows for easier communication in the cells

- During Interphase, cell develops into mature, functioning cell and prepares for division

- G1 is first phase, cell carries out normal cell functions and prepares to replicate DNA

- S is second phase of interphase, when cell copies DNA

-Chromosomes contain genetic material

- Chromatin is relaxed form of DNA in nucleus

What are the three main stages of the cell cycle?

- G2 follows S, cell prepares for division of its nucleus

- Mitosis and Cytokinesis follow interphase

- Mitosis, cell's nuclear material divides

- Cytokinesis, cytoplasm divides

- Prokaryotic cells use a different method called binary fission

Section 1 Assessment

Homework: Read 9.2,

vocab

- Sister Chromatids contain identical copies of DNA

- Centromere attaches sister chromatids

- Figure 6 Prophase

- Spindle fibers form in the cytoplasm from microtubules

- Spindle apparatus includes spindle fibers, centrioles, and aster fibers

- Nuclear envelope seems to disappear

- Spindle fibers attach to sister chromatids of each chromosome on both sides of the centromere and opposite poles of the cell

Mitosis

- First stage is prophase

- Cell's chromatin tightens/condenses into chromosomes

- Chromosomes are shaped like an X

- Each chromosome contains genetic material

- Each half of X is called a sister chromatid

Metaphase

Homework: Read 9.3,

Vocab

- Sister chromatids are pulled by motor proteins along the spindle apparatus towards the center of the cell and line up in the middle

Section 2

Assessment

What are the stages of mitosis?

Anaphase

Mitosis

Worksheets

- Microtubules of the spindle apparatus begin to shorten

Centromeres of each chromatid are pulled, so sister chromatids are separated

Telophase

- Last stage of mitosis

- Chromosomes arrive in poles of the cell and relax/decondense

- New nuclear membranes form

- Spindle apparatus disassembles

- Microtubules are used to help rebuild the cytoskeleton

Cytokinesis

- Divides the cytoplasm

- Results in two cells with identical nuclei

- Microfilaments constrict/pinch the cytolplasm in animal cells

- Plant cells form a cell plate and then two cells are formed

Data Analysis Lab 1

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