The document outlines the development of cell theory, highlighting contributions from scientists like Robert Hooke, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow, who established that all living things are composed of cells. It details the structure and functions of various cell components, including prokaryotes and eukaryotes, organelles like mitochondria and chloroplasts, and the composition and functions of the cell wall. Additionally, it discusses the types of plastids, their roles in nutrient storage and synthesis, and the differences between plant and animal cells.

1. Inside the Cell

2. Robert Hooke – first saw cells - 1665

3. Hooke’s Microscope

4. Hooke’s drawing of Cork Cells

5. Development of Cell Theory of Life
• 1838 – Matthias Schleiden – stated all
plants composed of cells
• 1839 – Theodor Schwann – stated all
animals also composed of cells – thus
claimed all living things composed of
cells
• 1858 – Rudolf Virchow – all cells come
from preexisting cells

6. Developers of Cell Theory
Matthias Schleiden Theodor Schwann Rudolf Virchow

7. Cell Theory
1. All organisms are
made up of cells.
2. Cells are the basic
unit of structure and
function in all
organisms.
3. All cells come from
cells that already
exist.

8. Prokaryotes vs. Eukaryotes
• Two broad groupings of life, based on
cell structure:
– Prokaryotes (e.g. bacteria)
• Lack a membrane-bound nucleus.
– Eukaryotes (e.g. plants and animals)
• Have a membrane-bound nucleus (nuclear
envelope)

9. Protoplasm
• A substance all cells are made of
• Mass of
– Protein
– Lipids
– Nucleic acid
– And water within the cell
– Except for the wall, everything in the it, cell
composed the organelles

10. Nucleus
“control unit”
• Contains a cell’s genetic information:
– Stored in the DNA sequences of chromosomes.

11. Nucleus
• Bounded by double membrane: nuclear envelope.
• Contains a nucleolus: where ribosomal RNA is synthesized.

12. Nucleus
• Nucleoplasm
– DNA
– Enzymes for repair and
reading DNA
– Histone proteins –
supports the DNA
– RNA of several types
– Water and substances
necessary for nuclear
metabolism

13. Vacuoles
“storehouse/
storage center”
• Plant and fungi have large
vacuoles.
• Growth
• Store water, ions, nutrients
and waste products.
• Digestive organelle
• Tonoplast

14. Plasma Membrane
(Plasmalemma)
• Selectively permeable
• Surrounds the inside of
the wall
• It mediates the
transport of substances
into and out of the
protoplasm

15. Cytoplasm
• Protoplasm less nucleus and vacuole
• Contains the following structures:

16. Mitochondria
“powerhouse of
the cell”
• Involved in producing ATP (cell’s energy currency.)
through cell respiration
• Cristae – provides room for enzymes
• Matrix – liquid inside the cristae
• Have two
membranes, their
own DNA and their
own ribosomes.

17. Types of Plastids
• Plastids are organelles that function primarily in nutrient
synthesis and storage of biological molecules
• located in the cell cytoplasm and are surrounded by a
double lipid membrane
• also have their own DNA
• Some plastids contain pigments and are colorful, while
others lack pigments and are colorless
• develop from immature, undifferentiated cells called
proplastids
• Proplastids mature into four types of specialized plastids:
a. chloroplasts, b. chromoplasts, c. gerontoplasts, and d.
leucoplasts.

19. a. Chloroplast
• green plastids responsible for photosynthesis and
energy production through glucose synthesis
• contains chlorophyll, a green pigment that
absorbs light energy
• commonly found in specialized cells called guard
cells located in plant leaves and stems
• Guard cells open and close tiny pores called
stomata to allow for gas exchange required for
photosynthesis

20. Chloroplasts
“food factory”
• Found in plant and algal cells.
• Have two membranes and their own DNA.

21. Chloroplasts
• Interior dominated by thylakoid membranes:
– Stacks of thylakoids: grana.
– Interior of thylakoids: lumen.
• Stroma: fluid surrounding thylakoids.

22. b. Chromoplast
• colorful plastids responsible for cartenoid
pigment production and storage
• Carotenoids produce red, yellow, and orange
pigments
• primarily located in ripened fruit, flowers,
roots, and leaves of angiosperms

23. b. Chromoplast
• responsible for tissue coloration in plants,
which serves to attract pollinators
• Some chloroplasts found in unripened fruit
convert to chromoplasts as the fruit matures
• Amyloplasts can also be converted to
chromoplasts by first transitioning to
amylochromoplasts (plastids containing starch
and carotenoids) and then to chromoplasts.

25. c. Gerontoplast
• plastids that develop from the degradation of
chloroplasts, which occurs when plant cells
die
• In the process, chlorophyll is broken down in
chloroplasts leaving only cartotenoid pigments
in the resulting gerontoplast cells

26. d. Leucoplast
• plastids that lack color and function to store
nutrients
• typically found in tissues that don't undergo
photosynthesis, such as roots and seeds

27. Types of leucoplasts include:

28. i. Amyloplast
• leucoplasts that convert glucose to starch for storage
• starch is stored as granules in amyloplasts of tubers, seeds,
stems, and fruit
• dense starch grains cause amyloplasts to sediment in plant
tissue in response to gravity, his induces growth in a
downward direction
• also synthesize transitory starch
– type of starch is stored temporarily in chloroplasts to be broken
down and used for energy at night when photosynthesis does
not occur
– found primarily in tissues where photosynthesis occurs, such as
leaves

30. ii. Elaioplasts
• leucoplasts that synthesize fatty acids and
store oils in lipid-filled microcompartments
called plastoglobuli
• important to the proper development of
pollen grains

31. iii. Etioplast
• light-deprived chloroplasts that do not contain
chlorophyll, but have the precursor pigment
for chlorophyll production
• Once exposed to light, chlorophyll production
occurs and etioplasts are converted to
chloroplasts

32. iv. Proteinoplasts
• also called aleuroplasts
• these leucoplasts store protein and are often
found in seeds

33. • Composed of proteins and RNA.
• Immersed in the protoplasm
• Involved in protein synthesis.
Ribosomes
“protein factory"

34. Endomembrane System
• Primary center for protein and lipid
synthesis in the cell.
• Consists of:
– Rough endoplasmic reticulum.
– Smooth endoplasmic reticulum.
– Golgi apparatus.
– Lysosomes.

35. Rough
Endoplasmic
Reticulum
(ER)
• Network of membrane-bound sacs and
tubules, lined with ribosomes.
• Many proteins are synthesized here.

36. Smooth
Endoplasmic
Reticulum
• Lacks ribosomes.
• Site of lipid biosynthesis. May store Ca2+ ions.

37. Dictyosome
(Golgi Apparatus
“transporter”
• Consists of flattened membranous sacs (cisternae).
• Receives products from rough ER and processes them.
• Sends finished products to cell surface (and other locations).

38. • Have a relatively acidic lumen (interior: pH = 5).
• Contain many digestive enzymes (acid hydrolases):
– Involved in digesting various molecules into monomers.
Lysosomes
“cell suicide bag”

39. Delivering Material
to Lysosomes

40. Receptor-
mediated
Endocytosis

41. Peroxisomes
the “liver” organelle
• Peroxisomal enzymes:
– Help metabolize fatty
acids into smaller
molecules.
– Help detoxify many
toxins, including alcohol.
– Include catalase, which
breaks down H2O2.

42. Microtubules
• Cytoskeleton - fibers which gives the
cell shape and structural stability
• Catch and guides vesicle to where they
are needed
• Means of motility of organelles and cells

43. Cell Wall
• Cell Wall:
– Protects the cell.
– Found in fungi, algae, and plants.

44. Cell Wall Definition
• a rigid layer that surrounds some types of
cells
• located outside the cell membrane whose
main function is to provide:
– rigidity
– strength
– protection against mechanical stress and
– infection

45. Cell Wall Definition
• also provides the cell with limited plasticity
that prevents the cell from rupturing due to
the turgor pressure
• Cutinized, preventing water loss and also
aid in cell-cell communication
• characteristic feature to cells of plants,
bacteria, fungi, many algae and some
archaea
• protozoans and animals do not have a cell
wall

47. Cell Wall Function
• Gives the cell a definite shape and structure.
• Provides structural support.
• Protection against infection and mechanical
stress.
• Separates interior of the cell from the outer
environment.
• It enables transport of substances and information
from the cell insides to the exterior and vice versa.
• Also helps in osmotic-regulation.

48. Cell Wall Function
• Prevents water loss.
• The physiological and biochemical activity of
the cell wall helps in cell-cell communication.
• It prevents the cell from rupturing due to turgor
pressure.
• Aids in diffusion of gases in and out of the cell.
• Also provides mechanical protection from
insects and pathogens.

50. Cell Wall Structure
• The composition of the cell wall differs from
one species to the other:
• bacteria – peptidoglycans
• archean - glycoproteins and polysaccharides
• Fungi - glucosamine and chitin
• Algae - it is composed of glycoproteins and
polysaccharides
• plant cell wall - cellulose, hemicellulose,
glycoproteins, pectins and lignin

51. Plant Cell Wall
• Presence of Cell wall is the major
difference between plant cell and animal
cell.
• What is its function?
• What are its components?

52. plant cell wall
• Cellulose - composed of linear chains of
covalently linked glucose residues
– very stable chemically and extremely
insoluble
– primary cell wall consists one glucose
polymer of roughly 6000 glucose units
– secondary wall their number increased to 13 -
16000 units
– Cellulose chains form crystalline structures
called microfibrils.

54. plant cell wall
• Hemicellulose
Any of several branched polysaccharides that
are composed of a variety of
different monosaccharides
– forms a
matrix with cellulose and lignin or pectin
in plant cell walls
– It is produced commercially from corn fiber.
• Glycoproteins - a type of protein molecule
that has had a carbohydrate attached to it

56. plant cell wall
• Pectins - pectin consists of a complex set of
polysaccharides
– present in most primary cell walls
– major component of the middle lamella, where it helps to
bind cells together, but is also found in primary cell walls
• Lignin - Lignin fills the spaces in the cell
wall between cellulose, hemicellulose,
and pectin components, especially in vascular and
support tissues
– mechanical strength to the cell wall and by extension the
plant as a whole
– plays a crucial part in conducting water in plant stems

58. Layers of the Cell Wall
• The middle lamella - It is first layer formed during cell division.
This layer is rich in pectin. It is the outermost layer, joins together
adjacent plant cells and holds them together.
• The primary cell wall - It is formed after the middle lamella. It is
composed of pectin compounds, hemicellulose and glycoproteins.
The layer consists of a framework of cellulose micro-fibrils, in a
gel-like matrix. It is thin, flexible and extensible layer.
• The secondary cell wall - It is a thick layer formed inside the
primary cell wall. It is extremely rigid and provides strength. It is
composed of cellulose, hemicellulose and lignin.

62. Typical Plant Cell

63. Typical Plant Cell