2. Robert Hooke [1665]
 examined thin sections of a bottle cork
under a crude microscope
 found hexagonal boxes or chambers packed
together like a honeycomb

3.  Robert Hooke used
the word 'cells' to
describe these
structures

4. Cell Theory
All living things are made up of cells.
Cells are the smallest working units of all
living things.
All cells come from preexisting cells through
cell division.

5. Definition of Cell
A cell is the smallest
unit that is capable
of performing life
functions.

6. Examples of Cells
Plant cell
Amoeba
Red blood cells
Bacteria
Nerve cell

7. A typical animal cell

8. Animal cells are spherical

9. A typical plant cell

10. Plant cells are cylindrical

11. Which structures are common to both
cells?

12. Cell membrane
 is a very thin, flexible layer round
the cell

13. Functions of the cell membrane
1. keeps the cell contents
together (like the sack)
2. controls what substances
go in and out of the cell as
it is semi-permeable

14. Cytoplasm
 is a thick liquid with particles in it
 contains ENZYMES which
control the chemical changes
taking place in the cell
 may contain food reserves e.g.
 starch grains
 oil droplets

15. Cell Parts:
Organelles

16. What are ‘organelles’?
 subunits in the cytoplasm that carry out a
particular function such as the:
 nucleus
 mitochondria

17. Nucleus
 each cell has one nucleus
 a cell cannot live for long without a nucleus
 the nucleus controls the activities of the cell
Nucleus in a
cheek cell.

18. The nucleus contains: thread-like
structures called:
CELL
 chromosomes
 chromosomes Chromosome
contain DNA
(deoxyribonucleic
acid)
DNA

19. The nucleolus is a dark region in the
nucelus
 Function of the nucleolus:
 certain chemicals are made e.g. RNA
(ribonucleic acid) which then work in the
cytoplasm
nucleolus

20. Vacuoles
Animal cells:
 have small vacuoles that are temporary
Amoeba engulfs
food. Phagocyte engulfs
bacteria.

21. Plant cells:
 have a large central,
permanent vacuole full
of SAP
SAP is a mixture of:
 sugars
 salts
 water
 pigments

22. Mitochondria
 are structures in which aerobic
respiration occurs
 are called the
‘power houses’ of
the cell as they
release energy
 are usually
sausage-shaped

23. Mitochondria
are seen only
by an
electron
microscope

24. Explain why there are more mitochondria
in muscle cells than in skin cells.
More
mitochondria
in muscle
cells as they
use more
energy.

25. Structures ONLY in plants
Cell wall
Chloroplasts

26. The cell wall is:
 a non-living structure surrounding the cell
membrane
 made of cellulose
 fully permeable i.e.
substances pass
freely through it
cell membrane cell wall

27. Functions of the cell wall
1. gives rigidity to the cell
2. together with the central vacuole, it
provides support

28. Chloroplasts contain the green
pigment: CHLOROPHYLL

29. Function of chlorophyll
 traps light for
photosynthesis
chloroplast

30. QUESTION: SEP, 2011
Give a reason for each of the following
observations.
i) Large permanent vacuoles are present in
plant cells. (2)
Gives shape and rigidity to
the plant cells.

31. QUESTION: SEP, 2011
Give a reason for each of the following
observations.
ii) Animal cells tend to have irregular shapes. (2)
Cells are surrounded by a thin cell membrane
which is not stiff.

32. QUESTION: SEP, 2011
Give a reason for each of the following
observations.
iii) Sperm cells are haploid. (2)
After fertilisation, the
diploid number of
chromosomes is
restored.

33. CELL SPECIALISATION
 specialisation is the process by which cells
change their shape to carry out a particular
task
 specialisation happens in multicellular
organisms

34. Examples of specialised animal cells:
 white blood cells
 change their shape
to engulf bacteria
 nerve cell
 contains a long
fibre to conduct
impulses

35. Examples of specialised animal cells:
 muscle cell
 elongated cell which can shorten
 red blood cell
 has no nucleus to have more space to
carry more oxygen

36. Examples of specialised plant cells:
1. guard cells
 bean-shaped cells with a
pore in between to
allow gas exchange
2. palisade cells
 elongated cells with
many chloroplasts to
carry out
photosynthesis

37. Examples of specialised plant cells:
3. epidermal cells
 transparent to
let light pass
through them

38. Tissues, Organs
&
Systems

39. Unicellular Multicellular
organism organism
one cell:  cells become
 carries out all the differentiated
vital functions into tissues
 is capable to live
on its own

40. Differentiated means
 cells become adapted during development
to a specific function

41. Cells in a tissue
have the same structure
and function
a tissue cannot live on its
own

42. Examples of animal tissues
 muscle tissue  blood tissue
 nerve tissue
 bone tissue

43. Examples of plant tissues
Photosynthetic tissue Vascular tissue:
xylem & phloem
Epidermal tissue:
Protects from water
loss & pathogens

44. QUESTION: SEP, 2011
Blood is an animal tissue.
List TWO plant tissues and give the
function of each. (6)
Epidermal tissue:
Photosynthetic tissue:
Vascular tissue:

45. Question: MAY, 2010
Write the appropriate plant or animal tissue for each
of the following descriptions. (6)
Description Name of tissue
Tissue used in the translocation of organic
solutes.
Tissue conducts nerve impulses.
Tissue contracts to support and move the
body.
Tissue found in leaf containing numerous
chloroplasts.
Tissue acts as the living protective layer in
leaf.
Tissue carries substances round the body.

46. Question: MAY, 2010
Write the appropriate plant or animal tissue for each
of the following descriptions. (6)
Description Name of tissue
Tissue used in the translocation of organic
solutes. Phloem
Tissue conducts nerve impulses.
Nervous
Tissue contracts to support and move the
body. Muscle
Tissue found in leaf containing numerous
chloroplasts.
Photosynthetic
Tissue acts as the living protective layer in
leaf. Epidermis
Tissue carries substances round the body.
Blood

47. Organism Levels of cellular
organisation
System
Organ
Tissue
Cell

48. Organs
 are made up of groups of tissues

49. Examples of
animal organs
Heart
Lungs
Kidneys
Brain
Skin
Ear
Eye
Uterus

50. Four plant
organs: Flower
Leaf
Stem
Root

51. Systems
 are made up of a group of organs
 e.g. heart + blood
vessels make up the
circulatory system

52. Examples of Systems
Skeletal
Circulatory
Immune
Respiratory
Digestive
Excretory
Reproductive
Nervous
Endocrine
Muscular

53. Question
To which systems of the body do the following
organs belong? Chose from the list:
circulatory nervous reproductive breathing
skeletal excretory digestive
a) Gut: digestive b) Bladder: excretory
c) Skull: skeletal d) Heart: circulatory
e) Ears: nervous f) Ovaries: reproductive
g) Lungs: breathing h) Spinal cord: nervous

54. Organism
 results from many systems working
together
I am an
organism.

55. Surface area
to volume
ratio

56. Why does an amoeba NOT require a
circulatory system?
An amoeba has a LARGE surface area to
volume ratio. Materials can move within the
amoeba quickly enough due to its small
volume.

57. What happens to the SA:Vol ratio as
the cube increases?

58. SA:Vol ratio limits cell size
Exchange of materials across surface can
happen only in the (small / large cube).

59. SA:Vol ratio limits cell size
Exchange of materials across surface can
happen only in the (small / large cube).

60. Large organisms need a:
1. respiratory system
 to take in O2 &
remove CO2
1. circulatory system
 to transport
materials to all cells
in the body

61. T HE END