1. Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells.
Protists, fungi, animals, and plants all consist of eukaryotic cells.

2. All cells have several basic features in common:
They are all bounded by a membrane, called a plasma membrane.
Within the membrane is a semifluid substance, cytosol, in which organelles are found.
All cells contain chromosomes, carrying genes in the form of DNA.
And all cells have ribosomes, tiny organelles that make proteins according to instructions from the genes

3. Bacterial cell
Animal cell

4. Basic differences between prokaryotic and eukaryotic cells
A major difference between prokaryotic and eukaryotic cells, indicated by their names, is that the chromosomes of a eukaryotic cell are located in a membrane–enclosed organelle called the _______________
. In a prokaryotic cell , the DNA is concentrated in a region called the nucleoid, but no membrane separates this region from the rest of the cell.
In contrast, the eukaryotic cell has a true nucleus, bounded by a membranous nuclear envelope
Within the cytoplasm of a eukaryotic cell, suspended in cytosol, are a variety of membrane–bounded organelles of specialized form and function. These are absent in prokaryotic cells.

5. Difference between Cytoplasm and Cytosol
The entire region between the nucleus and the plasma membrane is called _____________, a term also used for the interior of a prokaryotic cell.
Within the cytoplasm of a eukaryotic cell, is ________________, which has a variety of membrane– bounded organelles of specialized form and function, suspended in it.

6. Cell size matters!
Size is a general aspect of cell structure that relates to function.
The logistics of carrying out cellular metabolism sets limits on cell size.
At the lower limit, the smallest cells known are bacteria called mycoplasmas, which have diameters between 0.1 and 1.0 μm.
Most bacteria are 1–10 μm in diameter, a dimension about ten times greater than that of mycoplasmas.
Eukaryotic cells are typically 10–100 μm in diameter.

7. Why a cell can’t be too large
Metabolic requirements impose theoretical upper limits on the size that is practical for a single cell.
As an object of a particular shape increases in size, its volume grows proportionately more than its surface area.
(Area is proportional to a linear dimension squared, whereas volume is proportional to the linear dimension cubed.) Book

8. Thus, the smaller the object, the greater its ratio of surface area to volume
A high surface–to–volume ratio facilitates the exchange of materials between a cell and its environment

9. Which part is responsible for exchange of material between cell and its surroundings?
At the boundary of every cell, the ______________________functions as a selective barrier that allows sufficient passage of oxygen, nutrients, and wastes to service the entire volume of the cell .
For each square micrometer of membrane, only so much of a particular substance can cross per second.
Rates of chemical exchange with the extracellular environment might be inadequate to maintain a cell with a very large cytoplasm. The need for a surface area sufficiently large to accommodate the volume helps explain the microscopic size of most cells.
A sufficiently high ratio of surface area to volume is especially important in cells that exchange a lot of material with their surroundings, such as ___________cells.
Such cells may have many long, thin projections from their surface called _________________, which ______________________without an appreciable increase in __________________

10. How does plasma membrane look like?
The plasma membrane.  The plasma membrane and the membranes of organelles consist of a double layer (bilayer) of phospholipids with various proteins attached to or embedded in it.
The phospholipid tails in the interior of a membrane are _____________; the interior portions of membrane proteins are also hydrophobic.
The phospholipid heads, exterior proteins, exterior parts of proteins, and carbohydrate side chains are _____________ and in contact with the aqueous solution on either side of the membrane.
Carbohydrate side chains are found only on the ____________ surface of the plasma membrane.
PIC

11. Membrane-bound Enzymes
glucose + oxygen  carbon + water + energy
dioxide
C6H12O6
6O2
6CO2
6H2O
ATP  +

12. What are endomembranes?
In addition to the plasma membrane at its outer surface, a eukaryotic cell has extensive and elaborately arranged internal membranes, which partition the cell into compartments—______________ ______________.
These membranes also participate directly in the cell′s metabolism, because many enzymes are built right into the membranes. Furthermore, the cell′s compartments provide different local environments that facilitate specific metabolic functions, so incompatible processes can go on simultaneously inside the same cell

13. A little more on eukaryotic cells
…….

15. The Nucleus: Genetic Library of the Cell
The nucleus contains most of the genes in the eukaryotic cell (some genes are located in mitochondria and chloroplasts).
It is generally the most _____________ organelle in a eukaryotic cell, averaging about 5 μm in diameter.
The nuclear envelope encloses the nucleus, separating its contents from the cytoplasm

16. Nucleus Function Structure control center of cell protects DNA
instructions for building proteins
Structure
nuclear membrane
nucleolus
ribosome factory
chromosomes
DNA
Nucleus

17. The nucleus and its envelope
.  Within the nucleus are the chromosomes, which appear as a mass of chromatin (DNA and associated proteins), and one or more nucleoli (singular, nucleolus), which function in ________________ synthesis.
The nuclear envelope, which consists of ______ membranes separated by a narrow space, is perforated with pores and lined by the nuclear lamina

18. NUCLEAR ENVELOPE Function Controls passage of material Structure
histone protein
chromosome
DNA
Function
Controls passage of material
Structure
nuclear envelope
double membrane
membrane fused in spots to create pores
allows large macromolecules to pass through
nuclear
pores
pore
nuclear envelope
nucleolus
What kind of molecules need to pass through?

19. The nucleus and its envelope.
The nuclear envelope, which consists of two membranes separated by a narrow space, is perforated with pores and lined by the nuclear lamina.
The two membranes, are separated by a space of 20–40 nm. The envelope is perforated by pores that are about 100 nm in diameter.
At the lip of each pore, the inner and outer membranes of the nuclear envelope are continuous. An intricate protein structure called a pore complex lines each pore and regulates the entry and exit of certain large macromolecules and particles.
Except at the pores, the nuclear side of the envelope is lined by the nuclear lamina, a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope.
There is also much evidence for a nuclear matrix, a framework of fibers extending throughout the nuclear interior.

21. What is on the inside of nuclear envelope ?
Within the nucleus are the chromosomes, which appear as a mass of chromatin (DNA and associated proteins),
and one or more nucleoli (singular, nucleolus), which function in ________________ _________________

22. chromosome is made up…
Each chromosome is made up of a material called chromatin, a complex of proteins and DNA. Stained chromatin usually appears through both light microscopes and electron microscopes as a diffuse mass.
As a cell prepares to divide, however, the thin chromatin fibers coil up (condense), becoming thick enough to be distinguished as the familiar separate structures we know as chromosomes.
Each eukaryotic species has a characteristic number of chromosomes.

23. Nucleolus
A prominent structure within the nondividing nucleus is the nucleolus (plural, nucleoli ), which appears through the electron microscope as a mass of densely stained granules and fibers adjoining part of the chromatin.
Here a special type of RNA called ribosomal RNA (rRNA) is synthesized from instructions in the DNA.
Also, proteins imported from the cytoplasm are assembled with rRNA into large and small ribosomal subunits in the nucleolus.
These subunits then exit the nucleus through the nuclear pores to the cytoplasm, where a large and a small subunit can assemble into a ribosome..

24. Building Proteins

25. Proteins do all the work!
cells
Repeat after me…
Proteins do all the work!
DNA
organism

26. Cells functions Building proteins read DNA instructions build proteins
process proteins
folding
modifying
removing amino acids
adding other molecules
e.g, making glycoproteins for cell membrane
address & transport proteins

27. Protein Synthesis (an introduction)
The nucleus directs protein synthesis by synthesizing messenger RNA (mRNA) according to instructions provided by the DNA. ___________________________
The mRNA is then transported to the cytoplasm via the nuclear pores. Once an mRNA molecule reaches the cytoplasm, ribosomes translate the mRNA′s genetic message into the primary structure of a specific polypeptide. _____________________

28. Building Proteins Organelles involved The Protein Assembly Line
nucleus
ribosomes
endoplasmic reticulum (ER)
Golgi apparatus
vesicles
The Protein Assembly Line
Golgi apparatus
nucleus
ribosome ER
vesicles

29. Building Proteins Organelles involved The Protein Assembly Line
nucleus
ribosomes
endoplasmic reticulum (ER)
Golgi apparatus
vesicles
The Protein Assembly Line
Golgi apparatus
nucleus
ribosome ER
vesicles

30. 2. Cells need workers = proteins!
Making proteins
to run daily life & growth, the cell must…
read genes (DNA)
build proteins
structural proteins (muscle fibers, hair, skin, claws)
enzymes (speed up chemical reactions)
signals (hormones) & receptors
organelles that do this work…
nucleus
ribosomes
endoplasmic reticulum (ER)
Golgi apparatus

31. Proteins do all the work!
one of the major job of cells is to make proteins,
because…
proteins do all the work!
structural
enzymes
signals
receptors
DNA
proteins
cells

32. production of mRNA from DNA in nucleus
nuclear
membrane 1
production of mRNA from DNA in nucleus
small
ribosomal
subunit
large
cytoplasm
mRNA
nuclear pore 2
mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore

33. Ribosomes: Protein Factories in the Cell
Ribosomes, particles made of ribosomal RNA and protein, are the organelles that carry out protein synthesis. Cells that have high rates of protein synthesis have a particularly large number of ribosomes. For example, a human pancreas cell has a few million ribosomes. Not surprisingly, cells active in protein synthesis also have prominent __________________.

34. Nucleolus Function ribosome production
build ribosome subunits from rRNA & proteins
exit through nuclear pores to cytoplasm & combine to form functional ribosomes
small
subunit
large subunit
ribosome
rRNA &
proteins
nucleolus

35. (Keep in mind that both nucleoli and ribosomes, unlike most other organelles, are not enclosed in membrane.)

36. Ribosomes Function Structure protein production rRNA & protein
small
subunit
large
Ribosomes
Function
protein production
Structure
rRNA & protein
2 subunits combine
0.08mm
Ribosomes
Rough ER
Smooth

37. Types of Ribosomes Free ribosomes Bound ribosomes suspended in cytosol
synthesize proteins that function in cytosol
Bound ribosomes
attached to endoplasmic reticulum
synthesize proteins for export or for membranes
membrane proteins

38. Function of ribosomes and their types
Ribosomes build proteins in two cytoplasmic locales
Free ribosomes are suspended in the cytosol, while bound ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope.
Most of the proteins made on free ribosomes function within the cytosol; examples are enzymes that catalyze the first steps of sugar breakdown.
Bound ribosomes generally make proteins that are destined either for
insertion into membranes,
for packaging within certain organelles such as lysosomes
or for export from the cell (secretion).
Cells that specialize in protein secretion—for instance, the cells of the pancreas that secrete digestive enzymes— frequently have a high proportion of ________ ribosomes.
0.08mm
Ribosomes
Rough ER
Smooth

39. The endomembrane system
regulates protein traffic and performs metabolic functions in the cell Many of the different membranes of the eukaryotic cell are part of an endomembrane system, which carries out a variety of tasks in the cell. These tasks include
synthesis of proteins and their transport into membranes and organelles or out of the cell,
metabolism and movement of lipids, and
detoxification of poisons

40. The endomembrane system
includes the nuclear envelope,
endoplasmic reticulum,
Golgi apparatus,
lysosomes,
various kinds of vacuoles,
and the plasma membrane (not actually an endomembrane in physical location, but nevertheless related to the endoplasmic reticulum and other internal membranes). We have already discussed the nuclear envelope and will now focus on the endoplasmic reticulum and the other endomembranes to which the endoplasmic reticulum gives rise

41. Endoplasmic Reticulum
Function
works on proteins
helps complete the proteins after ribosome builds them
makes membranes
Structure
rough ER
ribosomes attached
smooth ER

42. Endoplasmic Reticulum
Function
processes proteins
manufactures membranes
synthesis & hydrolysis of many compounds
Structure
membrane connected to nuclear envelope & extends throughout cell

43. Types of ER
smooth

44. Smooth ER function Membrane production Many metabolic processes
synthesis
synthesize lipids
oils, phospholipids, steroids & sex hormones
hydrolysis
hydrolyze glycogen into glucose
in liver
detoxify drugs & poisons
ex. alcohol & barbiturates

45. The cells that actually synthesize and secrete SEX hormones—in the testes and ovaries, for example—are rich in ______________, a structural feature that fits the function of these cells

46. Smooth ER function Membrane production Many metabolic processes
synthesis
synthesize lipids
oils, phospholipids, steroids & sex hormones
hydrolysis
hydrolyze glycogen into glucose
in liver
detoxify drugs & poisons
ex. alcohol & barbiturates

47. How does detoxification happen?
Detoxification usually involves adding hydroxyl groups to drugs, making them more soluble and easier to flush from the body.
The sedative phenobarbital and other barbiturates are examples of drugs metabolized in this manner by smooth ER in liver cells. In fact, barbiturates, alcohol, and many other drugs induce the proliferation of smooth ER and its associated detoxification enzymes, thus increasing the rate of detoxification

48. The smooth ER
also stores calcium ions. In muscle cells, for example, a specialized smooth ER membrane pumps calcium ions from the cytosol into the ER lumen. When a muscle cell is stimulated by a nerve impulse, calcium ions rush back across the ER membrane into the cytosol and trigger contraction of the muscle cell. In other cell types, calcium ion release from the smooth ER can trigger different responses

49. Membrane Factory Build new membrane synthesize phospholipids
builds membranes
ER membrane expands
bud off & transfer to other parts of cell that need membranes
Membrane Factory

50. Rough ER function Produce proteins for export out of cell
protein secreting cells
packaged into transport vesicles for export
Which cells have lot of rough ER?

51. endoplasmic reticulum
nucleus
endoplasmic reticulum
protein on its way!
DNA
TO:
RNA
vesicle
TO:
TO:
vesicle
ribosomes
TO:
protein
finished protein
Golgi apparatus
Making Proteins

52. Synthesizing proteins
cytoplasm
cisternal
space
mRNA
ribosome
membrane of
endoplasmic reticulum
polypeptide
signal
sequence
Synthesizing proteins
ribosome

53. Golgi Apparatus Function Structure
finishes, sorts, labels & ships proteins
like UPS headquarters
shipping & receiving department
ships proteins in vesicles
“UPS trucks”
Structure
membrane sacs
vesicles
carrying proteins
transport vesicles

54. Golgi Apparatus

55. Vesicle transport vesicle budding from rough ER fusion of vesicle
with Golgi
apparatus
migrating
transport
protein
ribosome
Vesicle transport

56. endoplasmic reticulum nucleus
protein on its way!
DNA
TO:
RNA
vesicle
TO:
TO:
ribosomes
TO:
protein
finished protein
Golgi apparatus
Making Proteins

57. cytoplasm nucleus cell membrane nuclear pore protein secreted rough ER
transport
vesicle
Golgi
apparatus
smooth ER
rough ER
nuclear pore
nucleus
ribosome
cell
membrane
protein secreted
cytoplasm

65. Any Questions!!