Cambridge IGCSE Biology.cells

1. B1. Cells
ICGSE
Combined science

2. Characteristics of living things
1) Movement
2) Respiration
3) Sensitivity
4) Growth
5) Reproduction
6) Excretion
7) Nutrition

3. Movement : an action by an organism causing a change
of position or place
Respiration : the chemical reactions in cells that break
down nutrient molecules and release energy
Sensitivity : the ability to detect and respond to changes
in the environment.

4. Growth : a permanent increase in size
Reproduction : the processes that make more of the same
kind of organism
Excretion : removal from organisms of toxic materials and
substances in excess of requirements
Nutrition : taking in of materials for energy, growth and
development.

5. Cells
Cells are the basic structural and functional unit of all living organisms.

7. Eukaryotes Vs Prokaryotes
Eukaryotes
• Multicellular organism
(made of many cells)
• Have nucleus (DNA is in
the nucleus)
• Have complex structure
• Each cell have its own
function
Prokaryotes
• Unicellular organism
(made of one cell)
• No nucleus
• DNA in cytoplasm
• Have simple structure
• Only one cell function all
the living process

10. Subcellucar Structures
Features of a cell that have a specific functions.
E.g cell membrane nucleus etc.
Some subcellular can be found in all cells.
Others are unique to a particular cell type.

11. Cell Structure…..
Nucleus : contains DNA (genetic material) which controls
how cells grow or work.
Mitochondria :power house of the cell that performs cellular
respiration
Cell membrane :controls the substances in and out of the cell
Ribosomes :Sites of protein production in synthesis
Cytoplasm :chemical reactions take place in this jelly-like
substance

12. In addition to the subcellular parts found in animal cells, plant
cells have:
• A cell wall made of cellulose: gives the cell shape and
protection
• A permanent vacuole filled with cell sap: pushes the
cytoplasm against the cell wall, keeping the cell turgid
• Plant cells found in the leaf and stem may also
contain chloroplasts: the site of photosynthesis