General Biology 1 for STEM students

1. A Tour of the
Prepared by:
MR. KEVIN FRANCIS E. MAGAOAY
Faculty, SHS Biology Department
C h a p t e r 2
Cell

2. Learning Objectives:
 Explain the postulates of the cell theory
 Describe the structure and function of major and
subcellular organelles

3. Overview:
 Definition of cell
 Difference between animal and plant cell
 Brief history of cell discovery
 Three postulates of cell theory
 Cell organelles

4. What is a Cell?
 Cell is the fundamental unit of life
 Cell is the smallest unit that can perform all life
processes

5. Plant Cell Animal Cell

6. Cell
Wall Chloroplast
Central
Vacuole
nuclear
envelope
NucleusCytoskeleton
microtubules
microfilaments
intermediate
filaments
(not shown)
Ribosomes
Mitochondrion
Smooth ERPlasmodesma
Golgi Body
Plasma Membrane
Lysosome-Like
Vesicle
Rough ER
DNA in
nucleoplasm
nucleolus

7. Makes lipids, breaks down
carbohydrates and fats,
inactivates toxins
Smooth ER
Finishes, sorts, ships lipids,
enzymes, and proteins
Golgi Body
Modifies proteins made by
ribosomes attached to it
Rough ER
Digests, recycles materials
Lysosome

8. Plant Cell vs Animal Cell
 Animal cells do not contain chloroplast
 Animal cells are not surrounded by cell walls
 The vacuoles in plants are much larger than
those of animals

9. Microscopy
 The discovery and early study
of cells progressed with the
invention of microscopes in
1590 and their refinement
during the 1600s
 Three important parameters in
microscopy are magnification,
resolution and contrast

10. Review Name what part of the
microscope is being
pointed

11. Cell Discovery
Robert Hooke
(1665)
Anton Van Leeuwenhoek
(1676)
Matthias Schleiden
(1838)
Theodor Schwann
(1839)
Rudolf Virchow
(1858)

12. Robert Hooke (1665)
 Known as the “English Father of
Microscopy”
 Wrote and published “Micrographia”
 He observed pieces of cork under the
microscope.
 His observations led him to coin the
word “cell”.
 “Cell” means little rooms in Latin
 He compared the small boxes to the
small rooms that monks lived in.

13. Anton Van Leeuwenhoek (1676)
 He is known as the “Father of
Microscopy.”
 1673: He looked at pond scum
under the microscope and
discovered small organisms he
called animalcules or little
animals (Protists)
 1676: discovered bacteria

14. Robert Brown (1827)
He discovered the nucleus
using human cheek cells
Nucleus

15. LPO HPO

16. Matthias Schleiden (1838)
 German botanist
 Discovered that all plants
were made of cells

17. Theodor Schwann (1839)
 German zoologist
 Concluded that all animals
are made of cells.
Image credit:
https://de.wikipedia.org/wiki/Matthias_Jacob_Schleiden#/media/File:Matthias_Ja
cob_Schleiden_Botaniker_Jena_Th%C3%BCringen_Portrait_Stahlstich_um_185
0_b.jpg

18. Rudolf Virchow (1858)
 Rudolf Virchow was the
proponent of the Cell
Theory’s 3rd postulate, which
states that all cells come from
pre-existing cells.
Image credit:
https://de.wikipedia.org/wiki/Matthias_Jacob_Schleiden#/media/File:Matthias_Ja
cob_Schleiden_Botaniker_Jena_Th%C3%BCringen_Portrait_Stahlstich_um_185
0_b.jpg

19. Three Postulates of the Cell Theory
 All living things are made of cells.
 Cells are the basic units of structure and
function in living things.
 Living cells come only from pre-existing living
cells.

20. Cell Organelles
Other Specialized Structures

21. What are Cell Organelles?
 Also known as Little organs
 Are separated membranous compartments
inside the cells of the organs of living organisms.

22. Functions of Cell Organelles
 Maintain the shape and the structure of the cell
 Act as storage of nutrients
 Production of macromolecules
 Harvest energy
 Repair cell parts
 Digest substances

23. Cell Membrane
 surrounds the cell to
selectively screen the kinds
of substances that go in and
out of the cell
 phospholipid bilayer with
proteins that function as
channels, markers, and
receptors
 also contains cholesterol
which provides rigidity

24. Cytoplasm
 is a gel-like substance made
from dissolved proteins and
liquid encasing the cell and
giving it a fluid nature

25. Nucleus
 only found in eukaryotic cells
 a sphere that contains another
sphere called nucleolus
 stores the cell’s hereditary
DNA and controls cellular
activities like growth,
metabolism, protein synthesis
and reproduction.

26. Nucleolus
 is a sub organelle of the
nucleus composed of
proteins and ribonucleic
acids (RNA) whose role is
to assemble rRNA codes
for protein synthesis

27. Nuclear Envelope
 is a double membrane lipid
layer enclosing the
nucleus to protect the
DNA and nucleoplasm

28. Nucleoplasm
 is a gelatinous liquid inside
the nucleus containing the
enzymes and nucleotides.

29. Chromatin
 are cellular bundles
made up of complex
macromolecules of
DNA, RNA and protein.

30. Mitochondrion
 is the site of cellular
respiration and the
production of ATP
energy molecules which
gave it the title
“powerhouse of the
cell”

31. Endoplasmic Reticulum
 intercellular highway
 is the network of
membranous tubules
that transport the
materials needed by the
cell (nutrients, enzymes,
hormones, etc.).

32. Rough Endoplasmic Reticulum
 The grainy rough structure comes from its
attached ribosomes and is in charge in the
production of proteins

33. Smooth Endoplasmic Reticulum
 Not covered with ribosomes
 Involved in the synthesis of carbohydrates,
lipid and enzymes

34. Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum

35. Golgi Bodies
 Also known as Golgi
Apparatus
 consist of stacked flattened
sacks
 receive proteins, carbohydrates,
lipid and enzymes from the ER
 receiving, processing,
packaging and shipping

36. Lysosome
 found only in animal cells
 involved in intracellular
digestion
 contains hydrolytic
enzymes that are used to
digest macromolecules and
worn out organelles

37. Peroxisome
 spherical organelles that contain enzymes
within single membranes
 Produces 𝐻2 𝑂2
𝐻2 𝑂2 Enzyme+ = 𝐻2 𝑂 + 𝑂

38. Vacuole
 found in both plants and
animals
 used for temporary storage
of wastes, nutrients, and
water

39. Plastid
 Pigment bearing organelle
 Involved in making and
storing food

40. Plastid
LeucoplastChloroplast Chromoplast
Gerontoplast Amyloplast
Proteinoplast
Elaioplast

41. Cytoskeleton
 Network of fibers extending
throughout the cytoplasm
 Provide mechanical support
to the cell
 Maintain the cell shape

42. Cytoskeleton
Intermediate
Filaments
Microtubules Microfilaments

43. 8–12 nm
C Intermediate
filament
B
Microfilament
actin
subuni
t
A
Microtubule
tubulin
subuni
t
25 nm 6–7 nm
dimer
tetramer
sheet of
tetramer
s
coiled
sheet
10 µm
D A fluorescence micrograph shows microtubules (yellow) and
microfila- ments (blue) in the growing end of a nerve cell. These
cytoskeletal elements support and guide the cell’s lengthening in a
particular direction.

44. Centriole
 Play a major role in cell
division
 Composed of nine sets of
triplet microtubules

45. Cilia and Flagella
 hair-like organelles that extend from the surface of
cells
 when they are present in large numbers on a cell
they are called cilia
 when they are less numerous and longer they are
called flagella
 both organelles are composed of nine pairs of
microtubules arranged around a central pair.
 cell motility

46. Flagella Cilia