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
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
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
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
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
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
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
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
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
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.