Miller and Levine Biology Chapter 7 (Parrot book)

1. Cell Structure and Function
Chapter 7
Biology
Miller • Levine

2. The Scientists…
 Robert Hooke (1665)
 Viewed cork under a
microscope
 Called the chambers he
saw “cells”
 Anton van
Leeuwenhoek (1674)
 First to see living
organisms in a drop of
water

3. The Scientists…
 Matthias Schleiden (1838)
All plants are made of cells
 Theodor Schwann (1839)
All animals are made of cells
 Rudolf Virchow (1855)
All cells come from preexisting cells

4. The Cell Theory
 All living things are composed of
cells
 Cells are the basic units of
structure and function in living
things
 New cells are produced from
existing cells

5. Unicellular vs. Multicellular
 Unicellular – single-celled
organism
 Multicellular – many-celled
organism
Cell specialization – cells are
specialized to perform certain
functions
Cells → Tissues → Organs → Organ
systems → Organism

6. Prokaryotes vs. Eukaryotes
 Prokaryotes
Have a cell membrane &
cytoplasm, but do not have a
nucleus
Ex. Bacteria such as E.coli
 Eukaryotes
Have a nucleus, cell membrane,
cytoplasm & organelles
Ex. Plants, Animals, Fungi

7. Prokaryotes vs. Eukaryotes

8. Basic Cell Structures
 Cell membrane – thin, flexible
barrier around the cell; protects
the cell
Present in all cells
 Cytoplasm – material inside the
cell membrane (not including the
nucleus)
Prokaryotes & Eukaryotes

9. Cell Wall
 Found in many organisms,
including plants, algae, fungi
and nearly all prokaryotes
 Not found in animal cells
 Lies outside the cell membrane
 Main function is to provide
support & protection for the cell

10. Nucleus
 Almost all eukaryotic cells,
including plants and animals
have a nucleus
 Prokaryotes do not have a
nucleus
 Controls most cell process and
contains the DNA

11. Nucleolus and Nuclear Envelope
 Nucleolus:
Inside the nucleus
Where ribosomes are made
 Nuclear Envelope:
Double-membrane layer around
the nucleus
Allows material to move into and
out of the nucleus

12. Nucleus

13. Cytoskeleton
 Found in all eukaryotic cells
 Not found in prokaryotes
 A network of protein filaments
that helps the cell maintain its
shape
 It also is involved in cell
movement

14. Ribosomes
 Found in all cells
 Main function is to make
proteins
 Can be found floating in the
cytosol or attached to
endoplasmic reticulum

15. Endoplasmic Reticulum (ER)
 Found only in eukaryotic cells
 Where components of the cell
membrane are assembled
 Two kinds: Smooth ER & Rough
ER
Smooth ER: no ribosomes; makes
lipids
Rough ER: has ribosomes; involved
in making proteins

16. Endoplasmic Reticulum

17. Golgi Apparatus
 Found only in
eukaryotic cells
 Enzymes attach
carbohydrates &
lipids to proteins
 Send proteins to
their final
destination

18. Lysosomes
 Found in animal cells only
 Break down lipids,
carbohydrates & proteins from
food into particles that can be
used by the cell
 Also break down “dead”
organelles

19. Vacuoles
 Not found in prokaryotes
 Animal cells have small or no
vacuoles
 Plant cells have a large central
vacuole
 Store materials such as water,
salts, proteins & carbohydrates

20. Chloroplasts
 Found in all plant cells
 Some prokaryotes have them,
but most do not
 Use the energy from sunlight to
make energy-rich food
molecules during photosynthesis

21. Chloroplasts

22. Mitochondria
 Found in
eukaryotic
cells only
 Release
energy from
stored food
molecules

23. Cell Membrane
 Regulates what enters and leaves
the cell (selectively permeable)
 Provides protection and support
 Lipid bilayer – two layers of lipids
Proteins run through the layers
Carbohydrates are attached to some
of the proteins
Fluid Mosaic Model

24. Cell Membrane

25. Diffusion
 Molecules move from an area of
high concentration to an area of
low concentration
 Movement continues until
equilibrium is reached
 Many substances move across
the membrane by diffusion
 Does not require energy
(passive transport)

26. Diffusion

27. Osmosis
 The diffusion of water
Isotonic – equal concentration
 Nothing happens
Hypertonic – higher concentration
 Water moves out of the cell
Hypotonic – lower concentration
 Water moves into the cell
 No energy is required

28. Effects of Osmosis on Cells

29. Osmotic Pressure
 In pure water, an animal cell
would burst
 Plant cells are protected by their
cell wall
 Some freshwater organism have
special structures like contractile
vacuoles to get rid of extra
water

30. Facilitated Diffusion
 Some molecules cannot cross the
membrane without help
 Some of the proteins in the
membrane form protein channels
 Materials still move from higher to
lower concentrations
 No energy is required

31. Facilitated Diffusion

32. Active Transport
 Materials move
from lower
concentration to
higher
concentration
 Requires an
input of energy
 Works kind of
like a pump

33. Transport of Large Amounts
 Endocytosis – movement into
the cell
Phagocytosis – “cell eating” – solid
particles
Pinocytosis – “cell drinking” –
particles dissolved in water
 Exocytosis – movement out of
the cell

34. Phagocytosis

35. Pinocytosis