Anatomy and Physiology Chapter 3

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Anatomy and Physiology Chapter 3
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3.1 Introduction

• Cells vary considerable in size, shape, and
  function.
• The shape of cells in the body vary based on
  their function.

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3.2 Composite Cell

• Because cells vary so greatly in size, shape,
  content, and function, describing a typical
  cell is impossible.
• All of the structures described in the composite
  cell can NOT be found in every cell regardless of
  function.
• The organelles are found in the cytoplasm of
  the cell.

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Cell Organelles

• Cell Membrane
• Cytoplasm
• Endoplasmic reticulum (ER)
• Ribosomes
• Golgi Apparatus
• Mitochondria
• Lysosomes
• Peroxisomes

• Microfilaments and Mircotubules
• Centrosomes
• Cilia and flagella
• Vesicles
• Nucleus
• Nuclear envelope
• Nucleolus
• Chromatin

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Cell Membrane

• Extremely thin and semipermeable.
• The cell membrane contains many kinds of
  proteins, each with a special function.
• Function The membrane allows some substances to
  enter and leave the cell but not others,
  participates in signal transduction, and helps
  cells adhere to other cells. The membrane forms a
  boundary around the cellular contents,, and the
  basic structure of the cell membrane is a
  lipid-protein bilayer.
• Structure The basic framework of the cell
  membrane consists of a (bilayer) double layer of
  phospholipid, with fatty acid tails turned in.

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Cell Memebrane

• The Phosphate Head is HYDROPHILIC meaning "WATER
  LOVING".   Because of its hydrophilic nature, the
  head of a Phospholipid will orient itself so that
  it is as close as possible to water molecules.
• The Lipid Tails are HYDROPHOBIC meaning
  "WATER-FEARING", the Hydrophobic tails will tend
  to orient themselves away from water.

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Cytoplasm

• The cytoplasm consists of a clear liquid called
  cytosol, a supportive cytoskeleton, and networks
  of membranes and organelles.
• Cell activities occur mainly in the cytoplasm,
  where nutrients are received, processed, and
  used.

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Endoplasmic Reticulum

• ER is made up of membrane-bounded flatten sacs
  and elongated canals. ER provides a tubular
  transport system inside the cell.
• Rough ER Has ribosomes on its outer layer
• What does it function in the synthesis and
  transport of? PROTEIN
• Smooth ER No ribosomes. What does it function
  in the transport of? LIPIDS
• Vesicles that have a role in secretion are formed
  by the ER.

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Ribosomes

• They are found in the cytoplasm and ER
• They composed of Protein and RNA molecules.
• Function is protein synthesis.

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• Popeye is active because he eats spinach.
• However, for Popeye's cells to be active, his
  ribosomes help create proteins.

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Golgi Apparatus

• They are composed of about 6 flattened,
  membranous sacs.
• Function is to refine, package, and deliver
  proteins synthesized on ribosomes, and it
  packages the cells products.
• Vesicles that have a role in secretion are formed
  by the golgi apparatus (and ER).
• Plays a central role in the transport of new
  molecules from inside to outside the cell.

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Mitochondria

• Is the POWERHOUSE of the cell and contain enzymes
  that catalyze reactions that release energy from
  nutrients needed for aerobic respiration.
• Enzyme is a protein that catalyzes a specific
  biochemical reaction.
• Adenosine Triphosphate (ATP) energy.

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Lysosomes

• The "garbage disposals of the cell
• They contain powerful enzymes to break up old
  cell components and bacteria. Example white blood
  cells can engulf bacteria to fight bacterial
  infections.

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Peroxisomes

• Membranous sacs are abundant in liver and kidney
  cells.
• They contain enzymes that function in the
  synthesis of bile acids, breakdown of lipids,
  degradation of rare biochemicals, and
  detoxification of alcohol.

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Microfilaments and microtubules

• Thin, threadlike processes within the cytoplasm
  that function in various kinds of cell movement
  and that serve as the cytoskeleton of the cell.
• Microfilaments, made of the protein actin, cause
  various cellular movements.
• Mictotubules, made of the globular protein
  tubulin. Form 92 pattern.

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Centrosome

• is a structure made up of two hollow cylinders
  called centrioles.
• Function in cell reproduction.

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Cilia and flagella

• They are motile extensions from the cell.
• Cilia is short and move to-and-fro.
• Cilia function is to move fluids.
• Flagella are longer and move in an undulating
  wavelike motion.
• What is the only flagellated cell in the body?
  SPERM

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Vesicles

• Or vacuoles are formed by part of the cell
  membrane.
• They contain some liquid or solid material
  formerly outside the cell.
• Golgi and ER also form vesicles.

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Nucleus, nuclear envelope

• Is bounded by a double-layered nuclear membrane
  (nuclear envelope) containing relatively large
  nuclear pores that allow the passage of certain
  substances.

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Nucleolus

• Is a small, dense body composed mainly of RNA.
• Has no surrounding membrane.
• Ribosomes form in the nucleolus.

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Chromatin

• Consist of loosely coiled fibers of DNA and
  protein called chromosomes.

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3.3 Movements through cell membranes

• Passive mechanisms do not require energy.
• Diffusion
• Facilitated diffusion
• Osmosis
• Filtration

• Active mechanisms require cell energy.
• Active transport
• Endocytosis
• Exocytosis

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Passive

• Diffusion is the process by which molecules or
  ions scatter or spread spontaneously from high
  concentration to low concentration.
• Oxygen and carbon dioxide can diffuse readily
  through the cell membrane.
• Equilibrium is reached.

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Passive

• Substances that are not able to pass through the
  lipid bilayer need the help of membrane proteins
  to get across, this is called facilitated
  diffusion.
• Carrier molecules revolving doors are used to
  carry large molecules (glucose) across the
  membrane.

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Passive

• Osmosis is the diffusion of water.
• Solutions with a higher osmotic pressure than
  body fluids are called hypertonic.
• Solutions with a osmotic pressure equal to body
  fluids are called isotonic.
• Solutions with a lower osmotic pressure than body
  fluids are called hypotonic.

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Passive

• When fluid is forced through a membrane by
  hydrostatic or blood pressure, the mechanism is
  called filtration.
• Edema excess tissue fluid.

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Active

• Active transport is a process that moves
  particles through membranes from a region of low
  concentration to high concentration.
• Equilibrium is never reached.

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Active

• In endocytosis molecules that are too large to be
  transported by other means are engulfed by
  portion of the cell membrane and carried into the
  cell surrounded by a vesicle.
• Pinocytosis is a form in which cells engulf
  liquids.
• Phagocytosis is a form in which the cell takes in
  larger particles, such as a white blood cell
  engulfing a bacterium.
• Receptor-mediated is a form in which receptors
  bind specific particles, and they are drawn into
  the cell.

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• The reverse to endocytosis is exocytosis.

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3.4 The Cell Cycle

• The series of changes a cell undergoes from the
  time it is formed until it reproduces is called
  the cell cycle.
• The cell cycle is highly regulated. Most cells do
  not divide continually. Cells have a maximum
  number of times they can divide because of
  built-in clocks called telomeres on the tips of
  chromosomes.
• Mitosis cell division to form new cells (body
  cells).
• Meiosis cell division that forms sex cells
  (gametes).

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Mitosis (IPMAT)

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase

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Mitosis

• Interphase is a period of great metabolic
  activity in which the cell grows and synthesizes
  new molecules and organelles. During the S phase
  of interphase, the DNA of the cell is replicated
  in preparation for cell division.
• Prophase chromosomes and centrioles become
  visible and the nuclear envelope and the
  nucleolus disappear.

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• Metaphase the chromosomes line up in the middle
  of the cell. Spindle fibers are connected to the
  centromeres of each chromosome.
• Anaphase centromeres are pulled apart and
  chromosomes move in opposite directions.
• Telophase chromosomes change back into chromatin.
  Nuclear envelope and nucleolus re-form. Cell
  membrane pinches.

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• Cytokinesis is the division of cytoplasm.

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Cell Death

• Apoptosis is a form of cell death that is
  actually a normal part of development, sculpting
  organs from overgrown tissues.
• In the fetus, apoptosis carves away webbing
  between developing fingers and toes.
• Apoptosis follows a sunburn it peels away cells
  so damaged that they might otherwise turn
  cancerous.

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Cancer

• Cancer cells spread to distant areas
  (metastasize), display excessive growth
  (hyperplasia), and exhibit properties found in
  earlier stages (de-differentiation).

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Work Cited

• Golgi apparatus image.
• www.sirinet.net/jgjohnso/cell.html
• Mitochondria man image. www.mitochondria.us/pages/
  rebep_main.html
• Mitochondria image. www.mitochondria.us/pages/rebe
  p_main.html
• Cell image. www.merck.com/media/mmhe2/figures/fg00
  1_2.gif
• ER image. www.science.siu.edu/plant-biology/PLB117
  /JPEGs20CD/0073.JPG
• Ribosome image. //anthro.palomar.edu/biobasis/bio_
  5.htm

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• Cell membrane image. www.bioeng.auckland.ac.nz/ima
  ges/
• Popeye cartoon.
• www.//vilenski.org/science/safari/cellstructure/ri
  bo.html
• Lysosome image. www.people.virginia.edu/rjh9u/lys
  osome.html
• Cytoskeleton image. www.beyondbooks.com/lif71/4f.a
  sp
• Animated sheep. www.beyondbooks.com

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• Centrosome image. www.faculty.tcc.cc.fl.us/scma/sm
  ithh/centrioles.jpg
• Cilia and Flagella image. www.academic.brooklyn.cu
  ny.edu/biology/bio4fv/page/flagella-movement.html
• Nucleus image.
• www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBook
  CELL2.html
• Carrier Molecule image. www.msad54.k12.me.us/MSAD5
  4Pages/skow/CurrProjects/Biology/CrazyCells/Transp
  ort/transport20proteins.htm

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• Edema image. www.nucleusinc.com
• Mitosis image 1st pg. http//campus.queens.edu/fac
  ulty/jannr/cells/mit20pics/mitosis20animal.jpg
• Mitosis image. www.mun.ca/.../BIOL2060/CellBiol17/
  CB17_19.html