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Cytology: The Study of Cells

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Title: PowerPoint Presentation Author: Kari Rhoades Last modified by: onlygodcanjudge23_at_gmail.com Created Date: 8/27/2004 4:18:48 PM Document presentation format – PowerPoint PPT presentation

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Title: Cytology: The Study of Cells


1
Cytology The Study of Cells
2
Robert Hookes drawing of cork cells (cork cells
are the outer layer of roots)
3
Some History of Cells
Robert Hooke 1665 Matthias Schleiden 1838 Theodor Schwann 1839 Rudolf Virchow 1858
Observed cork slice under microscope. Coined the word cell. First to state that all plants are made of cells. First to state that all animals are made of cells. Stated that cells have to come from other cells.
4
  • The Cell Theory
  • All living things are made of cells.
  • Cells carry out the functions of living things.
  • Cells come from pre-existing cells.

5
How Cells Survive
  1. Unicellular Entire organism is made of one cell.

2. Multicellular Organism is made up of many
cells.
6
Levels of Organization for Multicellular
Organisms
  • Cell ? Tissue ? Organ ? Organ System ? Organism

7
What is a Cell?
  • A collection of living matter enclosed by a
    barrier that separates the cell from its
    surroundings it is the basic unit of all forms
    of life
  • BLOOD CELLS A BRAIN CELL

8
Levels of Organization of Cells (Continued)
Organ system A group of organs working
together.
Tissue A group of cells working together.
Organ A group of tissues working together.
9
And FinallyYOU!
  • Organism A body composed of organ systems that
    work together to carry out life processes.

10
Some Amazing Facts
  • There are over 210 different types of cells in
    your body (blood cell, heart cell, liver cell,
    kidney cell, muscle cell, nerve cell, bone cell,
    etc.)
  • There are over 100 Trillion Cells in your body
    (thats 100,000,000,000,000)
  • If you counted to 100 trillion, counting one
    number a second, it would take you 3,171,000
    years (that would be 31,710 lifetimes, assuming
    you lived to be 100)

11
  • The Inner Life of a Cell Video

12
Visible Light vs. Electrons
De Broglie Wavelengths 0.03 nm (very tiny
wavelengths)
Electromagnetic Waves Visible 400-700 nm (large
wavelengths)
13
Transmission Electron Microscope
  • Uses a beam of electrons instead of light.
  • Specimens must be sliced and treated with heavy
    metal.
  • Electrons that hit the heavy metal are stopped,
    and the ones that go through (transmitted) hit a
    photographic plate and create an image.
  • Advantage Allows you to see inside of the cell
    at over 10,000x

14
Scanning Electron Microscope
  • Specimens are whole.
  • Electrons bounce off of the heavy metal on the
    specimen and are collected by computer detector.
  • Advantage Produces a 3-D image of the object
    over 10,000x

15
Confocal Microscope
  • Uses lasers to scan for fluorescent dyes.
  • LASER is an acronym for Light Amplification by
    Stimulated Emission of Radiation.
  • Dyes are tagged to specific macromolecules in
    the cell.
  • Advantage Can determine the macromolecules that
    make up a cell.

16
Above TEM image of bacteria in termite
gut. Below SEM image of hairs on a violet leaf.
Onion cells Above on a light microscope, below
on a confocal microscope.
17
Compound Light Microscope
  • Uses visible light
  • Has two sets of lenses that work together to
    magnify objects.
  • Light shines up through stage and specimen, then
    is bent by lenses.
  • Maximum magnification 2500x. Light will break
    apart into rainbow if lenses bend it too much.
  • Advantage Living specimens can be observed.

18
All cells can be classified as one of these two
  • Prokaryotic (Bacteria Cells) or Eukaryotic (Plant
    and Animal Cells)

19
  • Prokaryotic Cell that does not have a nucleus.
  • Does NOT have a nucleus
  • Has a Plasmid (circular piece of DNA)
  • These cells are very small
  • Bacteria
  • Do not have organelles with a membrane(ribosomes
    do not have a membrane)
  • Eukaryotic Cell that has a nucleus (where DNA
    is contained).
  • Does have a nucleus
  • These cells are larger
  • Plants and Animals
  • Do have organelles with and without membranes
    (mitochondria, chloroplasts, nucleus do have a
    membrane)

20
Comparing Eukaryotic Cells
  • Animal cell (more round-shaped)
  • No cell walls
  • No chloroplasts
  • Many small, scattered vacuoles
  • Plant cell (more rectangular-shaped)
  • Has cell walls
  • Has chloroplasts
  • Has large central vacuole

21
What are organelles?
  • Organelle literally means tiny organs and just
    like the organs in our bodies (heart, liver,
    brain, lungs), organelles carry out specific
    functions.
  • The liquid that organelles float around in is
    called cytoplasm (cytocell, plasmliquid).

22
Mitochondria Has a membrane and is the
powerhouse of the cell because it creates energy
for our cells (respiration). This can be
identified by its bean-like shape and it looks
like a maze on the inside.
23
Ribosomes No membrane and is a two part
structure that contains RNA. Make cell proteins.
  • Ribosomes are those tiny dots everywhere.

24
  • Endoplasmic Reticulum (ER) Has a membrane and
    this is where the lipid component of the cell
    membrane is made. This also transports proteins
    and other parts to where they need to go and is
    considered the transport system.

25
Chloroplast Has a membrane and is an organelle
that contains chlorophyll.
Golgi Apparatus Has a membrane and is the
packaging system of the cell, meaning it
packages macromolecules.
Chlorophyll converts sunlight into glucose
(photo- synthesis), only found in plant cells!
26
Lysosomes Has a membrane and is the destruction
crew of a cell. Lysosomes contain enzymes, which
digest old cell parts. If all lysosomes break
open at once, the cell dies. Cell death is
called apoptosis.
Blebbing The bubbling of the cell membrane that
occurs at cell death. (The cells on the right are
blebbing.)
27
Vacuole Storage bubble made of a part of the
phospholipid bilayer from the cell
membrane. Waste vacuole Stores waste Food
vacuole Stores food (phagocytosis is shown in
the picture) Central vacuole Stores oil,
starch, and water in plant cells.
28
Cytoskeleton A 3-D support system made of
protein fibers. NOTE Above, the yellow strands
are the protein fibers making up the
cytoskeleton.
Flagella A flagellum is a long, whip-like tail
used in cell locomotion. The only human cell
that has a flagellum is the sperm cell, other
cells include bacteria.
29
The Cell (Plasma) Membrane
Cell (Plasma) membrane made up of two layers of
lipids (phospholipid bilayer) and allows
materials to move into and out of the cell and
provides protection for the cell. ALL CELLS HAVE
CELL MEMBRANES!
Hydrophilic water loving Hydrophobic water fearing
30
Proteins Found embedded in the membrane.
Function 1) transporting substances across the
cell membrane 2) support the cell
membrane 3) helps cells identify each
other Carbohydrates Attached to the outer cell
membrane - helps with identification and contact.
The Cell (Plasma) Membrane
31
Cell Walls Plant cell walls are made of
cellulose, a carbohydrate that makes raw
vegetables crunchy and the cell walls make trees
so strong. NOTE Prokaryotic cells also have
cell walls!
32
Parts of a Nucleus The nuclear membrane (nuclear
envelope). It is a phospholipid bilayer that has
small holes called nuclear pores. This allows
materials to pass into and out of the nucleus.
Inside is a dense circle called a nucleolus which
makes ribosomes.
Nucleus The control center of a cell. The
nucleus is usually the largest object in the cell
and contains the cells genetic material (DNA).
33
Cell Specialization Cells have specific
functions.
  • Red Blood Cell (RBC)
  • White Blood Cell (WBC)
  • T Cell
  • B Cell
  • Muscle Cell
  • Neuron (Nerve Cell)

34
Red Blood Cell
  • Its main function is to transport oxygen.

35
White Blood Cells
  • These are cells that are involved in your immune
    system (helps fight disease), 2 Types we will
    discuss
  • T-Cells Develop in the Thymus Gland and
    INDIRECTLY fight disease by triggering B-Cells to
    be made
  • B-Cells Develop in your Bone Marrow and DIRECTLY
    fight disease by producing antibodies (proteins
    that fight against infection of bacteria or
    viruses)

36
Thymus Gland Bone Marrow
37
Muscle Cells
  • Long, skinny cells that can contract (get short
    and fat) and relax, they connect to your bones
    and pull them so you can move.

38
Neuron
  • Neurons are nerve cells.
  • Carry information to and from the brain.
  • Be able to draw this and label the nucleus!

39
Hormones
  • Hormones are lipid and protein based chemicals
    that control body functions. The 3 types we will
    study are
  • 1) Estrogen
  • 2) Testosterone
  • 3) Adrenaline

40
Estrogen
  • Produced by the ovaries
  • Stimulates egg production
  • Produces female secondary sex characteristics
  • Breasts
  • Broader pelvis

41
Testosterone
  • Produced in the testes
  • Stimulates sperm production
  • Produces male secondary sex characteristics
  • Broader shoulders
  • Change in penis
  • Hair on face, back and chest

42
Adrenaline
  • Produced by adrenal glands
  • Triggers Fight or flight reaction
  • Increased heart rate
  • Increased breathing
  • Dilated (relaxed) pupils
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