Slides on cell structure and function

1. Cells
Chapter 2

2. What is the smallest Cell in the
World?
• http://www.cellsalive.com/howbig.htm

3. Learning Outcomes
At the end of the lesson, you should be able to:
• Identify chloroplasts, cell membrane, cell wall,
cytoplasm, cell vacuoles, nucleus, mitochondria,
ribosomes
• Identify endoplasmic reticulum and Golgi
apparatus (Pure)
• State the functions of the organelles identified
above
• Compare the structure of typical animal and
plant cells

4. • state, in simple terms, the relationship between
cell function and cell structure for the following:
• absorption – root hair cells
• conduction and support – xylem vessels
• transport of oxygen – red blood cells
• Differentiate cell, tissue, organ and organ system
Learning Outcomes….con’t

5. What is a cell??
• Basic structural and functional unit of living
things
• Building block of life
• All living things are made up of one or more
cells
• How big is a cell?
http://www.cellsalive.com/howbig.htm

6. What can we find in the cell?

7. What can we find inside a cell?
• Each living cell consists of living material called
protoplasm
• Protoplasm is made up of cell membrane,
nucleus and cytoplasm.
• Protoplasm is jelly-like, containing mainly water
and many other substances
• Protoplasm in one part of the body may be
different from another part of the body

8. What does a cell consist of?

9. Scientific Drawing
Lets try drawing an animal cell
• Use only pencil
• Write the Title of the drawing and underline
• Draw in 2D
• Clear solid lines; no sketching
• Label & annotate structures
• Label figure (e.g. Figure 1)
• Include scale *if applicable

10. Parts of a cell
• Cell surface membrane (plasma membrane)
• Cytoplasm
• Organelles
• Nucleus
• Mitochondria
• Vacuole
• Ribosomes
• Endoplasmic Reticulum ( Rough & Smooth)
• Golgi Apparatus
• Chloroplast (in plant cell)

11. Cell surface
membrane
(Plasma membrane)
Structure Function
Partially
permeable layer
around the cell
Control movement of substances in and
out of the cell.
Only allow some substances to pass
through, small molecules such as glucose,
oxygen and water can enter, but not
others such as waste substances.

12. Cytoplasm
Structure Function
Jelly-like substance
made up mainly of
water (70% water)
Acts as a medium for most chemical
activities of the cell to occur;
Contains enzymes and organelles.
Cytoplasm

13. • are subcellular structures (structures smaller than
cells) that perform specific jobs inside the cell.
• Eg: mitochondria, ribosomes, chloroplasts, vacuoles
Organelles

14. Nucleus
Structure Function
Contains
chromatin /
chromosome
(genetic
materials)
Controls cell activities, such as cell
repair and growth;
Controls cell division.

15. Vacuole
Structure Function
A fluid-filled
space enclosed
by a membrane;
Exists
temporarily in
animal cells.
Store substances such as water
and food temporarily.
vacuoles

16. Mitochondria
Structure Function
Small, rod-
shaped
organelles;
Highly folded
inner membrane
Site where aerobic respiration takes
place and energy is released.
(singular: mitochondrion;
plural: mitochondria)
“The power house
of the cell”

17. Ribosomes
Structure Function
Small, round structures;
Can be attached to ER
or found freely in the
cytoplasm.
Site where protein
synthesis takes place.

18. Lets Recap!
Parts of a cell

19. Cell surface
membrane
(Plasma membrane)
Structure Function
Partially
permeable layer
around the cell
Control movement of substances in and
out of the cell.
Only allow some substances to pass
through, small molecules such as glucose,
oxygen and water can enter, but not
others such as waste substances.

20. Cytoplasm
Structure Function
Jelly-like substance
made up mainly of
water (70% water)
Acts as a medium for most chemical
activities of the cell to occur;
Contains enzymes and organelles.
Cytoplasm

21. Nucleus
Structure Function
Contains
chromatin /
chromosome
(genetic
materials)
Controls cell activities, such as cell
repair and growth;
Controls cell division.

22. Vacuole
Structure Function
A fluid-filled
space enclosed
by a membrane;
Exists
temporarily in
animal cells.
Store substances such as water
and food temporarily.
vacuoles

23. Mitochondria
Structure Function
Small, rod-
shaped
organelles;
Highly folded
inner membrane
Site where aerobic respiration takes
place and energy is released.
(singular: mitochondrion;
plural: mitochondria)
“The power house
of the cell”

24. Ribosomes
Structure Function
Small, round structures;
Can be attached to ER
or found freely in the
cytoplasm.
Site where protein
synthesis takes place.

25. Endoplasmic Reticulum (ER)
 Two types:
 Rough ER
 Smooth ER

26. Rough ER
Structure Function
Ribosomes are
attached to its
outer surface,
hence its surface
appears rough
when seen under
the microscope
Rough ER helps to transport
proteins made by the ribosomes to
the Golgi apparatus for secretion
out of the cell.

27. Smooth ER
Structure Function
Smooth ER does not
have ribosomes
attached to its
membrane;
Smooth ER is more
tubular than rough
ER. It is connected to
the rough ER.
Synthesises substances such
as fats and steroids;
Converts harmful substances
into harmless substances –
Detoxification

29. Golgi Apparatus
Structure Function
The Golgi apparatus
consists of flattened
spaces surrounded by
membranes.
Vesicles (small spherical
spaces) fuse with one side
of the Golgi apparatus and
pinch off from the opposite
side.
Stores and modifies
substances made by the
ER; and
packages these
substances in vesicles for
secretion out of the cell

30. Transport of substances in the cell
• Vesicles are tiny spherical spaces enclosed by a
membrane.
• Vesicles containing substances made by the ER are
pinched off from the ER
• These vesicles then fuse with the Golgi apparatus
and release their contents into the Golgi apparatus for
modification

31. • Secretory vesicles containing these modified
substances are pinched off from the Golgi apparatus
and moves towards the cell membrane
• They fuse with the cell membrane and release their
contents outside the cell
Transport of substances in the cell

33. Brain Squeeze
• What does a cell remind you of ??
• Think of the different compartments within the cell
• And the different functions of the compartments
(organelle)

35. Analogy of a Cell
Cell Structures: Chemical Factory:
1. Nucleus
(Chromosomes that contain
genes)
Main office
2. Mitochondria Power Plant
3. Ribosomes Factory workers
4. Golgi Apparatus Packaging & Delivery
5. Lysosomes Recycling Centre
6. Vesicles Delivery Truck

37. Plant Cell
What are the Structural and Functional
difference of a plant cell from an animal cell?

38. chloroplast
central vacuole
rough endoplasmic
reticulum
ribosomes
cell wall
mitochondrion
Golgi complex
plasma
membrane
smooth endoplasmic
reticulum
free ribosome
vesicle
nuclear pore
chromatin
nucleolus
nuclear envelope
nucleus

39. **Remember the points to take note!
Lets try drawing a plant cell

40. • Its structures are similar to an animal cell
except for the presence of:
• Cellulose cell wall
• Chloroplasts
• One large central vacuole
Plant Cell

41. Cell Wall
Structure Function
Made of cellulose and
surrounds the entire
plant cell, surrounding
the cell membrane.
Cellulose is a type of
carbohydrates
The tough cellulose protects the cell
from injury and gives the cell a
regular shape.
The cell wall is fully permeable, unlike
the cell membrane.
Fun Fact: Can humans digest cellulose?

42. Chloroplast
Structure Function
Has stacks of disc-like
structures which
contain the green
substance called
chlorophyll.
Chlorophyll enables light energy to be
trapped and be converted into
chemical energy stored in food
(glucose) during the process
photosynthesis.

43. Vacuole
Structure Function
A plant cell has one
large central vacuole
containing cell sap.
The large vacuole is
enclosed by a
membrane called the
tonoplast.
Cell sap contains water and dissolved
substances such as sugars, mineral
salts and amino acids.

44. Micro-Question 1
Structure Animal cell Plant cell
Cellulose cell wall Absent Present
Chloroplasts Absent Present
Vacuoles Small, temporary
and many
Large, normally
one present

45. Micro-Question 2
The diagram shows four types of cells.
Which cell does not contain a nucleus?

46. Micro-Question 3
The diagram below shows a plant cell.
Which of the following is not a function of part T?
A to store food substances
B to secrete substances
C to store wastes
D to store water

47. Micro-Question 4
Which of the following statements describing the cell
membrane is incorrect?
A It is supported by lignin to give it a regular shape.
B It is a thin and elastic layer.
C It is a partially permeable membrane.
D It is mainly composed of fats and proteins.

48. Micro-Question 5
Which of the following is a correct description of the
permeability of the cell membrane and cell wall in a plant?
Cell wall Cell membrane
A fully fully
B fully partially
C partially fully
D partially partially

49. 1.4 Cell Organisation
Specialized Cells, Tissues, Organs and Systems

50. • Cell is the smallest working unit in a multicellular
organism.

51. • A tissue is a group of similar cells which work
together to perform a specific function
Muscle
tissue
Nerve
tissue

52. Specialised Tissues
Tissues Main Function
Animal
Blood Tissue Transports food and oxygen
Muscle Tissue Produces Movement
Nerve Tissue Transmits impulses
Epithelial Tissue Protects Cell
Plant
Epidermal Tissue Forms and protects surface of cell
Xylem Tissue Transports water and mineral salts
Phloem Tissue Transports food

53. What is an organ made up of?
• different tissues working together to perform
a particular function

54. Examples of organs
Liver
Lungs
Pancreas
Large
intestine
Brain
Ears
Heart
Stomach
Kidneys

55. What are organ systems?
• An organ system is made up of different
organs working together to perform a main
body function
Respiratory System Digestive System

57. • Can you name some examples of organs?
• Eg) In Animals:
Respiratory system –
Circulatory system –
Excretory system –
Digestive system –
Reproductive System –
Lung
Heart
Kidney, Lung, Skin
Stomach, Small
intestines
Ovary, Testes
Micro-Question 6

58. Organ systems in Plants?
• Reproductive system 
• Transport system 
• Root system 
Flowers
Vascular
bundle
Roots & vascular
bundle

59. Differentiation
•Differentiation is the process by which
a cell becomes specialised for a specific
function
•3 examples:
• Red blood cell
• Xylem vessel
• Root hair cell

60. Red Blood Cells
Function:
• Haemoglobin (red pigment) in cytoplasm
transports oxygen from the lungs to all parts
of the body.
• When haemoglobin combines
with oxygen, oxyhaemoglobin is formed.

61. Adaptations:
i.Absence of nucleus so as to contain more
haemoglobin and hence more oxygen
ii.Circular biconcave shape – increases surface area
to volume ratio for faster diffusion of gases in and
out of cell
iii.Elastic and can turn bell-shaped in order to allow
the cell to squeeze through small blood vessels
iv.Contain a red pigment, haemoglobin, to allow
oxygen to bind to the RBC to form
oxyhaemoglobin.
Red Blood Cells

62. Xylem Vessels
Function
i.Transport water and mineral salts from roots
up the stem and to the leaves
ii.Provide mechanical support for the plant
when bundled together

63. Adaptations
i.Absence of cross-walls and protoplasm enable
water to move easily through the lumen
(central space).
ii.Lignin deposited in the walls of xylem vessels
strengthens it and prevents the vessel from
collapsing.
iii.Narrow and hollow lumen allows water to be
moved easily up the stem.
Xylem Vessels

64. Root hair cell
• Absorb water via osmosis and mineral salts
from soil via diffusion.

65. • Adaptations
1. long and narrow protrusion/extension
of an epidermal cell to increase surface area
to volume ratio for more efficient absorption
of water and mineral salts from soil.
Root hair cell

66. • Adaptations
1. It has a very large vacuole that contains
concentrated cell sap solution, resulting in a
lower water potential thus allowing
absorption of water from the soil.
Root hair cell

67. Root hair cell

68. The table shows the presence, absence of a nucleus in three
types of cells. Which of the following is correct?
Red blood cell Root hair cell Xylem Vessel
A Present Absent Absent
B Present Absent Present
C Absent Present Absent
D Absent Present Present
Micro-Question 7