Cell Structures

1
Cell Structures

• Movement Organelles

2
Diffusion

• Movement of molecules from an area of high
  concentration to an area of low concentration
• Move to the lower concentration

3
Osmosis

• Diffusion of water

4
Osmotic Conditions

• Hypertonic Solution - contain a high
  concentration of solute relative to another
  solution (e.g. the cell's cytoplasm). When a cell
  is placed in a hypertonic solution, the water
  diffuses out of the cell, causing the cell to
  shrivel
• Hypotonic Solution - contain a low concentration
  of solute relative to another solution (e.g. the
  cell's cytoplasm). When a cell is placed in a
  hypotonic solution, the water diffuses into the
  cell, causing the cell to swell and possibly
  explode.
• Isotonic Solution solution where parts are
  equal in solute and solvent water moves across
  the membrane freely
• http//www.tvdsb.on.ca/westmin/science/sbi3a1/Cell
  s/Osmosis.htm

5
Cell Membrane

• 1. regulates the flow of materials in out of
  the cell
• 2. selectively permeable only certain
  materials pass thru
• 3. made up of bilayer of phospholipids with
  protein molecules jutting thru the layers

6
Cell Wall

• Prokaryotic Cell Wall
• Some have a 2nd outer layer composed of
  lipoproteins and lipopolysaccharides
• Eukaryotic Cell Wall
• 3 parts primary, middle lamella and secondary
  cell wall
• Primary cell wall cellulose
• Middle Lamella polysaccharides pectins
• Secondary cell wall cellulose and lignin

7
Cell Wall

• Eukaryotic Cell Wall Prokaryotic Cell Wall

8
Movement Through Membrane

• Simple Diffusion
• Molecules pass thru phospholipids in the membrane
• Only occurs for small non-polar molecules

9
Movement Through Membrane

• Passive Transport
• 1. Protein channels
• A. Proteins can form tunnels thru which
  molecules can diffuse
• B. Polar molecules can travel thru

10
Movement Through Membrane

• 2. Facilitated Diffusion
• A. Carrier proteins bond to a molecule on one
  side of the membrane, travel across and releases
  it on the other side.
• B. Carrier proteins bond with specific molecules
  (like enzymes do)

11
Movement Through Membrane

• Active Transport
• Works against a concentration gradient
• Requires an input of energy
• Contractile Vacuole is an example it forces
  excess water out of the cell even if it is
  against osmosis
• http//www.biologie.uni-hamburg.de/b-online/librar
  y/biology107/bi107vc/fa99/terry/images/ATPpumA.gif
  

12
Organelles

• Vacuoles sacs in cell which hold food, water,
  and enzymes
• Vessicles small vacuoles formed from part of
  Golgi bodies to hold proteins
• Lysosomes sac contains digestive enzymes to
  break down food or damaged organelles

13
Vacuoles and Vessicles

• Vacuole Vessicle

14
Organelles

• Nucleus contains cells DNA, controls proteins
  and their production
• Cells brain
• Surrounded by nuclear membrane which has pores to
  allow RNA to pass thru into the endoplasmic
  reticulum
• Nucleolus inside nucleus, makes ribosomes
• Usually each nucleus has several nucleoli

15
Nucleus
16
Organelles

• Ribosomes
• Tiny structure responsible for protein production
• Has its own ribosomal RNA
• Located in the endoplasmic reticulum

17
Endoplasmic Reticulum (ER)

• Network of tunnels running from nucleus to Golgi
  bodies
• Rough ER contains ribosomes, Smooth ER does not
• Function carry proteins to the Golgi bodies and
  make new cell membrane

18
Endoplasmic Reticulum (ER)
19
Golgi Bodies

• Stacks of membranous pouches at the end of the ER
• Receive proteins from ER and send them to other
  organelles by putting them in vessicles

20
Mitochondria

• Where cellular respiration occurs
• Eukaryotes have thousands in their cells
• Inner folded membrane (cristae) where respiration
  occurs
• Have their own DNA and can replicate themselves

21
Mitochondria
22
Cytoskeleton

• Network of protein fibers allow the cell to
  change its shape four types
• 1. microtubules- involved in cell reproduction
• 2. intermediate filaments strength/shape
• 3. microfilaments cell locomotion
• 4. microtrabeculae
• connect organelles

23
Plastids(only found in plants)

• Chloroplasts
• green due to chlorophyll
• Have grana and thykaloids
• Photosynthesis occurs in thykaloids

24
Plastids(only found in plants)

• Chromoplasts
• Are like chloroplasts but not green
• Allow photosynthesis to occur in different
  lighting conditions

25
Plastids(only found in plants)

• Leucoplasts
• Colorless, have no pigments
• Stores starch proteins and lipids
• Releases them when the cell needs them

26
Unicellular Movement

• Cilia
• Tiny hairs on outside of cell membrane used for
  locomotion

27
Unicellular Movement

• Flagella
• Large hair on outside of cell membrane used for
  locomotion
• Both are composed of microtubules

28
Unicellular Movement

• Psudopodia not truly an organelle
• Extension of the cytoplasm which the rest of the
  cytoplasm flows to
• Used for movement
• Surrounds and captures prey