1. RAYAT SHIKSHA’S SANSTHA’S
KANYA VIDYALAYA DEHU

2. Chapter 5 Std : 9 Cells : basic units of structure & function of living things

3. Introduction to Cell Theory
History of Scientists:
1665:
Robert Hooke coins the term "cell" to describe chambers in cork
Anton Von Leeuwenhoek perfects techniques for grinding microscope lens to make the first microscope
1674:
Mathais Schleiden concluded that plants are composed of cells
1838:
Theodore Schwann concluded that animals are composed of cells
1839:

4. Robert Hooke
Coined the term “cell”

5. Anton van Leeuwenhoek
First compound light microscope

6. Matthias Schlieden
All plants are made of cells

7. Theodor Schwann
All animals are made of cells

8. Rudolf Virchow
Cells can only arise from pre-existing cells

9. Main Ideas of Cell Theory
Those early scientists did experiments on living things and developed CELL THEORY
Main Ideas of Cell Theory
All living things are made of one or more cells 1)
Cells are the basic units of structure & function of living things 2)
All cells come from existing cells 3)

10. What are cells made of?
Cells are mostly water. The rest of the present molecules are:
protein
nucleic acid
carbohydrate
lipid
other

11. What are cells made of? By elements, a cell is composed of:
60% hydrogen
25% oxygen
10% carbon
5% nitrogen

12. Special Cell Process:
There are approx. 100 trillion cells in the human body
100,000,000,000,000
Cells need certain substances to stay alive
ANSWER:
Osmosis
Diffusion
QUESTION:
How do they get these substances?

13. Rules of Diffusion & Osmosis
All substances that enter or leave a cell must cross its surface
Small cells function better than large cells
WHY? … because substances do not have to travel as far to reach the center of small cells
So, the larger the cell…the longer it takes to cross it

14. Osmosis- the movement of water across the cell membrane
important because cells are surrounded by water molecules
the number of H2O molecules inside and outside the cell must be almost equal.
when the molecules are even throughout a space
Equilibrium-
the process of osmosis allows this balance to happen

15. Diffusion
Diffusion – the movement of particles from an area of high concentration to an area of low concentration.

17. Example: like a big plastic bag with tiny holes in it
CELL MEMBRANE
holds the cell together
keeps all of the pieces (like the organelles and the cytoplasm) inside the cell
controls what goes in and out of the cell
Example: like a big plastic bag with tiny holes in it

18. How does the cell membrane work?
Has 2 layers of MOLECULES = BILAYER
Bi means two
The layers are made up of molecules called phospholipids
**THINK OF a sandwich with two pieces of bread and some stuffing on the inside

19. Cell Membrane: PHOSPHOLIPIDS
One end of the molecule is “afraid” of the water and one end “loves” being in the water.
Proteins are stuck inside the membrane
Proteins are across the bilayer and make the holes that let ions and molecules in and out of the cell

20. CYTOPLASM Protoplasm- everything inside the cell membrane
Cytoplasm- everything inside the cell membrane & outside of the nucleus except the cell’s nucleus
Cytosol:
Mostly H2O
Contains organelles
Contains salts, dissolved gasses & nutrients

21. CYTOPLASM
cytoplasm

22. CYTOSKELETON Chief functions include:
movement of material through the cell for stuff not diffusion or osmosis
maintaining the shape of the cell
keeping the cell from getting smashed

23. The Organelles -nucleus -cytoplasm -nucleolus -cytoskeleton
-cell membrane -vacuole
-mitochondria -chloroplast
-golgi Apparatus centrioles
-lysosomes ribosomes
-endoplasmic reticulum(ER)
*Rough ER & Smooth ER

24. Nucleus The “brain” of the cell Controls all of the
cellular activities
DNA is inside the nucleus

25. Nucleus are found inside the nucleus CHROMOSOMES-
carry the information that determines what traits a living thing will have
Chromosomes –

26. NUCLEOLUS
The dark area in the nucleus
Like a tiny nucleus inside the nucleus.

27. Endoplasmic Reticulum
also known as the “ER”
it is an organelle inside the cell that is
made up of membranes that are in the CYTOPLASM of the cell
There are two different
Smooth ER
Rough ER

28. Smooth ER
Main function is to collect, maintain & transport things
Shaped slightly tubular
Creates steroids
Stores Ions for the cell to keep nutrients balanced

29. Rough ER
It has bumps all over it giving it a “rough” appearance
Bumps are called RIBOSOMES
ER collects the proteins (built by the ribosomes) and creates a bubble around them
VESICLE- is formed when the ER pinches off a part of its membrane

30. Secretion
Exocytosis
The release of intracellular molecules (hormones or proteins)
EXOCYTOSIS-

32. GOLGI APPARATUS Also called the Golgi Complex
It is made up of a stack of flattened out sacs …like a loose stack of pancakes
WHAT DOES IT DO?
1) it takes simple molecules and combines them to make larger molecules.
2) takes those larger molecules and puts them into packs called GOLGI VESICLES

33. LYSOSOMES (primarily animal)
They combine with the food taken in by the cell
The enzymes in the lysosome bond to food & digest it (acidic interior)
Next…smaller molecules are released which are absorbed by the mitochondria

34. LYSOSOMES
When an organelle no longer works, the lysosome will attach itself to it and break it down like food (kind of like a cannibal)
Chemicals can then be reabsorbed or excreted
Lysosomes can also destroy the cell if it breaks open accidentally
“Suicide Sacs”
UV light damages lysosome membrane
The enzymes inside the lysosome spread throughout the cell and digest it -

35. Mitochondria Mito = Mighty / Power The Power-House of the cell
They break down food molecules so the cell has the energy to live
If a cell needs a lot of energy…it will have more mitochondria
vilenski.org/science/safari/ cellstructure/mito.html

36. The Mitochondria structure has three main parts:
OUTER MEMBRANE: covers the mitochondria
INNER MEMBRANE: folds many times to increase the surface area because chemical reactions
(glycolysis) occur here
So…the more space it has the more energy it can create

37. MATRIX: a fluid that has water and proteins all mixed together
(like a solution)
The proteins
take the food molecules in and combine them with Oxygen to release the energy

38. VACUOLE Vacuoles are “bubbles” that float in the cell
Vacuoles are more important to the survival of plant cells than they are to animal cells

39. VACUOLE: STORAGE IN PLANT CELLS
Vacuoles in plants support structure
Vacuoles hold onto things that the cell might need…like a backpack
There are some vacuoles that hold onto waste products, similar to having a big septic tank
Storing waste products protects the cell from contamination

40. VACUOLE CONT’D
So, when there is no water…the vacuole shrinks and the cell wall is the only thing holding the plant together.

41. You will know that a plant's vacuoles are shrinking when you see the plant begin to droop over
HOLDING UP THE WALLS

42. Turgor Pressure- force exerted by the water entering (osmosis) the vacuole, which then swells exerting internal force on the cell wall
Causes “rigidity” so the plant my increase by stacking cells

43. SOLAR energy radiated from the sun is captured by plants(chloroplast)
Then it is instantaneously changed into ELECTRICAL energy
Then packaged as CHEMICAL energy
Chloroplast

44. Chloroplast photosynthesis takes place inside the chloroplast
the process in which plant use water, carbon dioxide, and energy form the sun to make food
Photosynthesis-

45. Chloroplast No energy transformation is 100% efficient
Not all the solar energy captured is converted to electrical and then chemical energy.
Some of it gets lost as heat or other forms of energy (light)
fig.cox.miami.edu/Faculty/ Dana/105F00_11.html

46. Ribosomes
small dot-like structures in cells
they are often associated with forming
rough ER
Ribosomes are the site of protein synthesis in cells
they are made in the nucleus of the cell
A ribosome can make the average protein in about one minute

47. Ribosome Structure
Ribosomes are made up of proteins and ribonucleic acid(RNA)
These molecules are arranged into two subunits
These subunits are attached to each other and together form the entire ribosome
When viewed through a light microscope the ribosomes appear as dots

48. Types of Cells: Eukaryotic Unicellular Protists Multicellular Fungi
Plants
Animals
Prokaryotic
Bacteria
Archaea

49. Eukaryotic Characteristics Unicellular (Protists)
Multicellular (fungi, plants, animals)
Membrane bound Nucleus
Contains Organelles
Linear DNA

50. Eukaryotic Cell

51. Prokaryotic Characteristics
Unicellular (some multicellular in very rare cases)
Lacks a membrane bound nucleus
Lacks membrane bound organelles
Has a cell membrane (cell wall)
Has ribosomes (protein production)
Circular DNA

52. Prokaryotic Cell

53. THANK YOU
BY:SUCHETA KHINDKAR