Unit 4: Cell Structure

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Unit 4 Cell Structure Function
http//koning.ecsu.ctstateu.edu/cell/cell.html
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Discovery of Cells

• Robert Hooke (1600s) discovered little
  chambers (cells) in cork plant
• Anton van Leeuwenhoek (1600s)used microscope to
  view living things in pond water. Saw things
  swimming around!

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Discovery of Cells, cont.

• Matthias Schleiden (1838) concluded plants made
  of cells
• Thoedor Schwann (1839) concluded all animals
  made of cells

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Cell Theory

• 1. All living things are made up of cells.
• 2. Cells are the smallest working units of all
  living things.
• 3. All cells come from p_____________ cells
  through cell division.

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Definition of Cell

• A cell is the smallest unit that is capable of
  performing life functions.

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Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
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Two Types of Cells

• Prokaryotic
• pro- means before (like pre)
• karyon means nut or kernel
• No n______________
• Older life forms are prokaryotes
• Eukaryotic
• eu- means true karyon kernel
• Has nucleus
• newer life forms are prokaryotic

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Prokaryotic Cells

• Do not have o___________ surrounded by membranes
• V. few internal structures
• All prokaryotes are
• one-celled organisms
• B___________

http//library.thinkquest.org/C004535/prokaryotic_
cells.html
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Eukaryotic Cells

• Contain organelles surrounded by membranes
• Most living organisms are eukaryotic
• Plants, animals, f_____, algae

Plant
Animal
http//library.thinkquest.org/C004535/eukaryotic_c
ells.html
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Typical Animal Cell
http//web.jjay.cuny.edu/acarpi/NSC/images/cell.g
if
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Typical Plant Cell
http//waynesword.palomar.edu/images/plant3.gif
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Eukaryotic Cell Parts

• Organelles

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Surrounding the Cell
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Cell Membrane

• Outer membrane of cell that controls m______
• in and out of the cell
• Double layers of fat phospholipid bilayer

What part of this word tells you that the cell
membrane is made of fats?
http//library.thinkquest.org/12413/structures.htm
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Cell Wall

• Most commonly found in
• plant cells
• bacteria
• fungi
• S_____ p_____ cells
• Made of carbohydrate

http//library.thinkquest.org/12413/structures.htm
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Inside the Cell
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Nucleus

• Directs cell activities
• Separated from c_______ by nuclear membrane
• Contains genetic material - DNA

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Nuclear Membrane

• Surrounds nucleus
• Made of t____ layers
• Openings allow material to enter and leave
  nucleus

http//library.thinkquest.org/12413/structures.htm
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Chromatin

• Form DNA takes most of the time.
• Like spaghetti
• Made of DNA wrapped up w/p_______.

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Chromosomes

• In nucleus
• DNA wrapped up tight by proteins called
  histones
• Contain instructions for traits characteristics
  

http//library.thinkquest.org/12413/structures.htm
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Nucleolus

• Inside nucleus
• Contains RNA to build proteins

http//library.thinkquest.org/12413/structures.htm
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Cytoplasm

• Gel-like mixture
• Surrounded by cell membrane
• Contains hereditary material in prokaryotes

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Ribosomes

• Each cell contains thousands
• Make proteins
• Found on e___________ r________ floating in the
  cytoplasm

http//library.thinkquest.org/12413/structures.htm
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Endoplasmic Reticulum

• Moves materials around in cell
• Smooth type
• lacks ribosomes
• Located in organisms that produce _____ like
  _____
• Rough type (pictured)
• R_____ are embedded in surface
• Located in organs responsible for producing
  proteins, like the ________

http//library.thinkquest.org/12413/structures.htm
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Mitochondria

• Produces energy through chemical reactions by
  breaking down f___ c_________.
• Also known as the powerhouse of the cell
• Controls level of water and other materials in
  cell
• Recycles and decomposes proteins, fats, and
  carbohydrates

http//library.thinkquest.org/12413/structures.htm
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Golgi Bodies

• Protein 'packaging plant'
• Move materials within the cell
• Move materials out of the cell

http//library.thinkquest.org/12413/structures.htm
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Lysosome

• Digestive factory' for proteins, fats, and
  carbohydrates
• Transports undigested material to c___ m_______
  for removal
• The cell will break down if lysosome breaks!

http//library.thinkquest.org/12413/structures.htm
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Vacuoles

• Membrane-bound sacs for storage, digestion, and
  waste removal
• Contains water solution
• Help plants maintain s______

http//library.thinkquest.org/12413/structures.htm
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Chloroplast

• Usually found in plant cells (not in animal)
• Contains green chlorophyll
• Where p__________ takes place

http//library.thinkquest.org/12413/structures.htm
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Centrioles

• Used during animal cell division (not present in
  plant most other cells)

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Flagellum

• Is a whiplike structure that extends outside the
  cell.
• Is used for movement.

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Cilia

• Small, hairlike projections that extend outside
  the cell
• For m_______ capturing food

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Prokaryotic Cells

• Ribosomes
• DNA or RNA
• cytoplasm

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Cell Boundaries

• Cell Membrane
• 1. Controls what goes in out
• 2. Support protection

• Cell Wall
• 1. Support protection

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Diffusion through Cell Boundaries

• Every cell lives in a liquid environment
• Membrane controls movement of dissolved molecules
  back forth (in out of cell)

• (Remember a solution contains a
• Solvent the substance that dissolves the other
  stuff (often water)
• Solute the substance that gets dissolved (salt,
  sugar, ions, etc.)

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Concentration of Solutions

• The greater the ratio of solute to solvent, the
  higher the concentration.
• Ex
• Solution 1 dissolve 5 g of salt in 1L of water.
  Concentration 5g/L
• Solution 2 dissolve 10 g of salt in 1L of
  water. Concentration10g/L

This solution has a higher salt concentration
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Diffusion

• In solution, particles move constantly, colliding
  spreading out.
• Diffusion is the movement of particles from area
  of greater to lesser concentration (b/c of random
  motion.)
• Requires no energy to move substances across a
  membrane (b/c moved by random motion)

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Isotonic

• When solute concentration is equal throughout the
  solution

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OsmosisVideo

• The diffusion of water through a membrane
• Some molecules are too large to move through a
  membrane

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How Osmosis Workssee Fig 7-15 on p 185

• If there is a selectively permeable membrane
  separating 2 solutions w/differing concentrations
  of solute,
• Water will move from the side where it is in
  greater concentration to where it is in lesser
  concentration. (R to L in picture)

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Concentration of Solutions

• Isotonic when the concentration of particles is
  the same on both sides of membrane

• Hypertonic above strength- the stronger of the
  2 solutions (L side)

• Hypotonic below strength- the less
  concentrated of the 2 solutions (R side)

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How Osmosis Works in Cellssee p 186 of text, Fig
7-16

• Isotonic Cell maintains its shape

• Hypertonic

• Hypotonic