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Cells
Eukaryotic
Prokaryotic
Viruses (not cells!)
Animal Cell (Eukaryotic)
Cell surface membrane
Smooth
endoplasmic
reticulum
Nucleus
Nucleolus
Nuclear
membrane
Rough
endoplasmic
reticulum
Lysosome
Ribosome
Golgi apparatus
Golgi vesicle
Mitochondrion
Plant Cell (Eukaryotic)
Cell surface membrane
Cell wall
Nucleus
Nucleolus
Nuclear
membrane
Mitochondrion
Rough
endoplasmic
reticulum
Golgi apparatus
Ribosome
Chloroplast
Vacuole
Specialized cells
In a single-celled organism, all the functions necessary for
life must be carried out in one cell. In contrast, multicellular
organisms can delegate jobs to particular groups of cells.
Cells that have adapted to a specific function are known as
specialized cells.
Specialized cells are grouped into tissues, which combine
to make organs and organ systems.
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© Boardworks Ltd 2008
Tissues, organs and organ systems
11 of 32
© Boardworks Ltd 2008
Prokaryotes and Viruses
Prokaryotic Cells
• Use the information on the sheet to compile a
list of similarities and differences between the
structures of prokaryotic and eukaryotic cells.
Similarities
•
•
•
•
Cytoplasm
Cell membrane
Ribosomes
Cell wall (plant cells)
Differences in prokaryotes
•
•
•
•
Smaller than eukaryotes
No membrane-bound organelles
Ribosomes are smaller
No nucleus – just a single closed loop of DNA,
free in the cytoplasm and not associated with
proteins
• Cell wall contains murein (a glycoprotein) not
cellulose
More differences: some prokaryotes
have…
• One or more plasmids made of additional
DNA
• A capsule surrounding the cell
• One or more flagella
Viruses
•
•
•
•
Very small
Acellular
Non-living
Consist of genetic material (e.g. DNA/RNA), a
capsid and several attachment proteins.
Viruses
•
•
•
•
Need living cells to act as a host
Attach to the cell surface membrane
Insert their genetic material into the cell
The cell copies the genetic material as part of its
‘normal’ processes.
• Each copy acts as the genetic code to produce a
new capsid – the cells normal protein synthesis
methods ensure this happens
• When the cell is filled with new viruses it bursts
open and the viruses are released to infect more
cells.
HOMEWORK
• Complete the first section of your 3.2
homework booklet INCLUDING the exam
questions on cell structure.
• Hand in on Thursday 26th November
• Failure to meet either of these criteria will
result in a detention on Friday lunchtime.