The document discusses the structure and function of eukaryotic cells. It describes that cells contain organelles, including a nucleus that holds the genome, and membrane-bound structures like the endoplasmic reticulum, Golgi apparatus and mitochondria. The processes of transcription and translation are summarized, where DNA in the nucleus is transcribed into mRNA which is then translated by ribosomes into proteins. The stages of the cell cycle, including interphase and mitosis, are also outlined.

1. Lecturer, Department of Pharmacy
East West University

2. The basic unit of life…

3. Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria

4. The cell is the smallest unit of life.
Microorganisms such as bacteria, yeast, and
amoebae exist as single cells.
By contrast, the adult human is made up of about 30
trillion cells which are mostly organized into
collectives called tissues.

5. Cells are nothing but some compartments…
Eukaryotic cells are the membrane bound
compartments!!!

6. • Prokaryotic
&
• Eukaryotic

7. Do not have structures
surrounded by
membranes
Few internal structures
One-celled organisms,
Bacteria

8. Contain organelles surrounded by membranes
Most living organisms
Plant Animal

9. Why don’t we find any giant
amoeba or bacteria???

10. Study of the structure and
function of
eukaryotic cells

12. Organelle means
“little organ”
Found only inside
eukaryotic cells
All the stuff in
between the
organelles is cytosol
Everything in a cell
except the nucleus is
cytoplasm

13. Organelles

15. Outer membrane of cell
that controls movement
in and out of the cell
Made of a phospholipid
bilayer

17. 1. lipids
2. functional proteins
3. carbohydrates

19. 1. Membrane Lipids (42% of its weight)

26. Double layer of phospholipid molecules:
hydrophilic heads
—toward watery environment, both sides
hydrophobic fatty-acid tails
— inside membrane
barrier to ions and water soluble compounds

27. Integral proteins:
within the membrane
Peripheral proteins:
inner or outer surface of the membrane

28. 1. Anchoring proteins (stabilizers):
– attach to inside or outside structures
2. Recognition proteins (identifiers):
– label cells normal or abnormal
3. Enzymes:
 catalyze reactions
4. Receptor proteins:
– bind and respond to ligands (ions, hormones)
4. Carrier proteins:
– transport specific solutes through membrane
4. Channels:
– regulate water flow and solutes through membrane

29. 1. Proteoglycans and glycoproteins
2. Glycolipids
extend outside cell membrane
form sticky “sugar coat” (glycocalyx)

30. 1. Lubrication and protection
2. Aids attachment of cells
3. Specificity in binding (receptors) e.g. antigens and
enzymes
4. Cell-cell recognition and interaction

31. 1. cytosol (fluid):
 dissolved materials:
 nutrients, ions, proteins, and waste products
2. organelles:
 structures with specific functions
All materials inside the cell and outside the
nucleus

32. Difference between cytosol and extracellular fluids:-
1. Conc. of K+
is high in cytosol
2. Conc. of Na+
is high in extracellular fluids
3. Suspended protein is high
4. Reserve small quantity of carbohydrates and amino acids
(extracellular fluid is carrier only)
Both cytosol and extracellular fluids (interstitial fluid) contain
insoluble materials. In case of cytosol, these masses are known as
inclusions.
Ex. Cytosol:- Glycogen granules, lipid droplets, pigment granules
Extracellular fluids:- Melanine in skin, Mineral deposit in bone

33. Nonmembranous organelles:
no membrane
direct contact with cytosol
 Membranous organelles:
covered with plasma membrane
isolated from cytosol

35. 6 types of nonmembranous organelles:
1. cytoskeleton
2. microvilli
3. centrioles
4. cilia
5. ribosomes
6. proteasomes

36. Structural proteins for shape and strength
It functions as the cells skeleton.
I. Microfilaments
II. Intermediate Filaments
III. Microtubules
IV. thick filaments (muscle cells)
Cytoskeleton includes
It provides an internal
protein framework that
give cytoplasm
strength and flexibility

37. Actin
Microtubules
Intermediate
filaments

38. Micro (Thin) filaments composed of
the protein called actin:
1. Anchor the cytoskeleton to
integral protein of plasma
membrane (provide additional
mechanical strength)
2. interact with other proteins for
consistency of the cytoplasm
3. Pairs with thick filaments of
myosin for movement of a
portion or to change the shape of
entire cell.
smallest of the cytoskeletal elements (6 nm in diameter)

39.  Mid-sized between
microfilaments and thick
filaments ( 7- 11 nm)
most durable
cytoskeletal elements
1. strengthen cell and
maintain its shape
2. stabilize the position of
the organelles
Protein composition varies from cell to cell

40. Large, hollow tubes of tubulin
protein:
1. strengthen cell and anchor
organelles
2. change cell shape
3. move vesicles within cell
(affected by molecular motor-
kinesin and dynein)
4. form spindle apparatus
5. Form structural componant (e.g
centrioles and cillia)
Largest components
# change over time
Form by tubuline
molecule

41. Increase surface
area for
absorption
Attach to
cytoskeleton

42. Centrioles form spindle
apparatus during cell
division
Centrosome: cytoplasm
surrounding centriole
Nine triptels
Not present in RBC, skeletal muscle
cells, cardiac muscle cells, nerve cells

43. Cilia move fluids across
the cell surface
• Found in Lungs, reproductive tracts.
• It can “beat” rhythmically.
Relatively long, slender extension of plasma membrane.

44. 5. Ribosomes
• Build polypeptides in protein synthesis
• Two types:
– free ribosomes in cytoplasm:
• proteins for cell
– fixed ribosomes attached to ER:
• proteins for secretion
60% RNA + 40% protein, 25 nm in diameter
• # vary cell to cell (contrast: liver cell/adiposites)
• Two sub-unit (large and small)
• rRNA

45. For protein synthesis, two subunit must join together with mRNA

46. Proteasomes
Ubiquitin ( a molecular tag)
• Contain enzymes (proteases)
• Remove and break down damaged or abnormal
proteins
( Disassemble damaged proteins for recycling)
• Require targeted proteins to be tagged with
ubiquitin

47. Membranous Organelles
• 5 types of membranous organelles:
1. Endoplasmic reticulum (ER)
2. Golgi apparatus
3. Lysosomes
4. Peroxisomes
5. Mitochondria

48. endo = within
plasm = cytoplasm
reticulum = network
Endoplasmic Reticulum (ER)
Cisternae are storage chambers
within membranes
• Forms cisternae
• Rough ER (RER) contains ribosomes
– Form transport vesicles
• Smooth ER (SER)
– Involved in lipid synthesis
Intracellular membranes
involved in synthesis, storage,
transportation and detoxification

49. Endoplasmic Reticulum (ER)

50. Functions of ER
1. Synthesis of proteins, carbohydrates, and lipids
2. Storage of synthesized molecules and materials
3. Transport of materials within the ER
4. Detoxification of drugs or toxins

51. Smooth Endoplasmic Reticulum (SER)
• No ribosomes attached
• Synthesizes lipids and carbohydrates:
– phospholipids and cholesterol (membranes)
– steroid hormones (reproductive system)
– glycerides (storage in liver and fat cells)
– glycogen (storage in muscles)
- store Ca+2
- detoxification of drugs

52. Rough Endoplasmic Reticulum (RER)
Surface covered with ribosomes:
1. active in protein and glycoprotein synthesis
2. folds polypeptides into protein structures
3. encloses products in transport vesicles
Workshop and shipping depot

53. Golgi Apparatus
Vesicles enter forming face and exit maturing face

54. Carry materials to and from Golgi apparatus

55. Ejects secretory products and wastes

56. Powerful enzyme-containing vesicles:
lyso = dissolve, soma = body

57. Primary lysosome:
formed by Golgi and inactive enzymes
Secondary lysosome:
lysosome fused with damaged organelle
digestive enzymes activated
toxic chemicals isolated

58. Clean up inside cells:
1. break down large molecules
2. attack bacteria
3. recycle damaged organelles
4. ejects wastes by exocytosis

59. 1. lysosome membranes break down
2. digestive enzymes released
3. cell decomposes
4. cellular materials recycle
auto = self, lysis = break
Self-destruction of damaged cells (Apoptosis):

60.  break down fatty acids, organic compounds produce
hydrogen peroxide (H2O2).
 Peroxisomes harbor enzymes that rid the cell of
these toxic peroxides.
 replicate by division
Are enzyme-containing vesicles:
Carry enzymes that neutralize toxins

61. Have smooth outer
membrane and folded inner
membrane (cristae)
Matrix: fluid around cristae

67. Mitochondrion takes chemical energy from food
(glucose):
produces energy molecule ATP
Figure 3–9b

68. Aerobic metabolism (cellular respiration):
mitochondria use oxygen to break down food and
produce ATP
glucose + oxygen + ADP → carbon dioxide + water + ATP
•Glycolysis:
– glucose to pyruvic acid (in cytosol)
•Tricarboxylic acid cycle (TCA cycle):
– pyruvic acid to CO2 (in matrix)
The Reactions

69. It is the cell’s control center
• Largest & most conspicuous structure in a cell
• Only visible organelle under light microscope
Store all information to direct synthesis
of diff. 1,00,00 proteins.
It determine -
• structure of the cell
• what function it will perform
Most cells have single
nucleus
Exception-
Muscle cells - polynucleated
RBC- non-nucleadted

71. Nucleolus: Dark staining area
(made of - RNA,enzymes & histone)
Synthesize rRNA. Prominent in liver
cell (why?)
Nuclear envelope: double
membrane around the nucleus
Nuclear pores:
communication
passages
Perinuclear space: between
2 layers of nuclear envelope
Nucleoplasm: fluid
containing ions,
enzymes, nucleotides,
and some RNA
• Nuclear matrix:
‒ support filaments
DNA: all information to
build and run organisms

77. Vital Statistics of Human Genome

78. Gene: DNA instructions for 1
single protein

80. The chemical language of DNA instructions:
sequence of bases (A, T, C, G)
triplet code:
3 bases = 1 amino acid

85. Transcription:
copies instructions from DNA to mRNA (in nucleus)
Translation:
ribosome reads code from mRNA (in cytoplasm)
assembles amino acids into polypeptide chain

86. Processing:
by RER and Golgi apparatus produces protein

87. A gene is transcribed to mRNA in 3 steps:
gene activation
DNA to mRNA
RNA processing

88. Uncoils DNA, removes histones
Start (promoter) and stop codes on DNA mark
location of gene:
coding strand is code for protein
template strand used by RNA polymerase molecule

89. Enzyme RNA polymerase transcribes DNA:
binds to promoter (start) sequence
reads DNA code for gene
binds nucleotides to form messenger RNA (mRNA)
mRNA duplicates DNA coding strand, uracil replaces
thymine

90. At stop signal, mRNA detaches from DNA molecule:
code is edited (RNA processing)
unnecessary codes (introns) removed
good codes (exons) spliced together
triplet of 3 nucleotides (codon) represents one amino
acid

93. mRNA moves:
from the nucleus
through a nuclear pore

94. mRNA moves:
to a ribosome in cytoplasm
surrounded by amino acids

95. mRNA binds to ribosomal
subunits
tRNA delivers amino acids to
mRNA

96. tRNA anticodon binds to mRNA
codon
1 mRNA codon translates to 1
amino acid

97. Enzymes join amino acids
with peptide bonds
Polypeptide chain has
specific sequence of amino
acids

98. At stop codon,
components separate
Stop Codons
In RNA:
UGA: "U Go Away"
UAA: "U Are Away"
UAG: "U Are Gone“
In DNA:
TAG: "They Are Gone"
TAA: "They Are Away"
TGA: "They're Going Away"

99. Direct control through synthesis of:
structural proteins
secretions (environmental response)
Indirect control over metabolism through enzymes

100. Cell division is the reproduction of cells
Apoptosis is the genetically controlled death of cells
Mitosis is the nuclear division of somatic cells
Meiosis produces sex cells
cell division
The Cell Life Cycle

101. Most somatic cells spend the majority of their lives in
this phase
Interphase includes
G1
S
G2
Interphase
The Cell Life Cycle

102. The Cell Life Cycle

103. DNA Replication

104. The structure of a chromosome after DNA Replication

105. Prophase
Metaphase
Anaphase
Telophase
During cytokinesis, the cytoplasm divides and
cell division ends
Mitosis

106.  The chromosomes are in an extended form and seen as
chromatin in the electron microscope.
 The nucleus is visible
Interphase

107.  The chromosomes are seen to consist of two chromatids joined
by a centromere.
 The centrioles move apart toward opposite poles of the cell.
 Spindle fibers are produced and extend from each centrosome.
 The nuclear membrane starts to disappear.
 The nucleolus is no longer visible.
Prophase

108.  The chromosomes are lined up at the equator of the cell.
 The spindle fibers from each centriole are attached to the
centromeres of the chromosomes.
 The nuclear membrane are disappeared.
Metaphase

109. The centromere split, and the sister chromatids separate
as each is pulled to an opposite pole.
Anaphase

110. Telophase
 The chromosomes become longer, thinner, and less distinct.
 New nuclear membranes form.
 The nucleolus reappears.
 Cell division is nearly complete.

111. Interphase, Mitosis, and Cytokinesis

112. Interphase, Mitosis, and Cytokinesis