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Cellular Activities
By the students
Asmaa abd mouhammed
Asmaa mouhammed tawfiq
Asmaa nazar
Asmaa wisam
CELL MEMBRANE

BY THE STUDENT

ASMAA ABD
Cell Membrane
Controls what enters and leaves the cell
 Separates cell from the environment
 Made of two layers of phospholipids
 Has protein ‘gates’ that pass materials in
and out.

Diffusion
The movement of particles from an area where
they are crowded to areas where they are less
crowded.
 Does not use any energy from the cell! (no
ATP)
 Particles must be very small (oxygen, water, salt)
 The Diffusion Applet

Examples of diffusion
Scent of perfume
 Smell of cookies baking
 Food coloring mixing in water

Osmosis
The movement of WATER across a
MEMBRANE
 A special type of diffusion
 When water is mixed with other materials,
the water is less concentrated
 Water moves from where it is more
crowded to where it is less crowded

Passive Transport
Small particles move through protein
gates in cell membrane.
 A special type of diffusion.
 Does NOT use any energy from cell (no
ATP).

Active Transport
Small particles move through protein gates in
cell membrane.
 Particles move from less crowded areas to
more crowded areas.

◦ (like blowing up a balloon)

NEEDS energy from cell (ATP)
ENDOCYTOSIS

BY THE STUDENT

ASMAA MOUHAMMED
Endocytosis
Cell membrane surrounds and pinches off
to bring large molecules/materials into
the cell.
 Brings in food, proteins, chemical
messages into the cell.
 NEEDS lots of energy from the cell
(ATP)!
 Pinched off membrane forms vesicles

Exocytosis
Vesicles of materials that need to leave the
cell, merge with the cell membrane and
expel the materials from the cell.
 Uses lots of ATP from the cell.
 Used to send waste and proteins from the
cell.
 endocytosis/exocytosis

Cellular Respiration
Who – plants and animals
 What – Food is combined with oxygen to release
energy
(ATP)

sugar and oxygen  carbon dioxide and water
(ADP ATP)
When – All of the time
 Where – in mitochondria of cells
 Why – to make ATP to power all of the cell’s
activities

Fermentation
Produces ATP without using oxygen.
 Produces much less ATP than cellular
respiration
 2 types:

◦ Bacteria & fungi – produces alcohol as waste
 Used to make wine, beer and liquor
◦ Animals – produces lactic acid (causes ‘burn’
and cramping in muscles)
CELL DIVISION

BY THE STUDENT

ASMAA NAZAR
Cell Division

Used for:
◦ Growth
◦ Repair (healing a cut or break)
◦ Reproduction
Before a cell divides it must:

Copy its DNA

How many chromosomes are there in a
human? Fruit Fly? A potato?
Human
-
46 chromosomes
(23 pairs)
Fruit Fly -
8 chromosomes
(4 pairs)
Potato -
48 chromosomes
(24 pairs)
The number of chromosomes has nothing to do
with the complexity of an organism
3 stages of eukaryotic cell division
Stage 1 – The cell grows and copies its
organelles and chromosomes
2) Stage 2 – DNA Separation = Mitosis
3) Stage 3 – Cell division into two cells
identical to the original cell
1)
Mitosis
The process of nucleus duplication.
 Ensures that each cell receives a copy of
each chromosome.
 4 parts

DUPLICATION
BY THE STUDENT
ASMAA WISAM
Duplicate
DNA is copied so that each new cell has
a complete set of instructions.
 Nuclear membrane breaks down so DNA
can move in cell

Lineate

Pairs of chromosomes (DNA) line up in the
middle of the cell
Separate

One copy of each strand of DNA moves
to opposite sides of the cell.
Cytokinesis
Cytoplasms split into 2
 Each cell has own copies of DNA and
organelles
 Cells are identical
