A slideshow for students studying IB Biology with animations and videos

1. IB Biology
2 Cells
2.3 Eukaryotic Cells
All syllabus statements ©IBO 2007
All images CC or public domain or link to original material.
Jason de Nys
http://commons.wikimedia.org/wiki/File:Biological_cell.svg

2. 2.3.1.
Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell

3. 2.3.2 Annotate the diagram from 2.3.1 with the functions of each named structure.
The Nucleus contains
the chromosomes
which comprise most
of the DNA in a cell
- It is the largest
organelle
- It has a double layer
membrane
- mRNA, transcribed
from the DNA in the
nucleus, exits through
pores more in 3.3, 3.4 and 7.1 and 7.2
- Some cells have
multiple nuclei The bright blue stains are nuclei in HeLa
cells. Read “The Immortal Life of
Henrietta Lacks” for a fascinating story
of the origin of HeLa cells
http://commons.wikimedia.org/wiki/File:HeLa_cells_stained_with_Hoechst_33258.jpg

4. http://commons.wikimedia.org/wiki/File:Diagram_human_cell_nucleus.svg

5. The Cell membrane is the boundary of the cell.
• It acts as a “gatekeeper”, preventing the entry or exit of some
molecules and facilitating the movement of others.
• It is a phospholipid bilayer
• It is permeable to oxygen and carbon dioxide
• It is impermeable to water and charged particles, they must
enter through special proteins embedded in the membrane
More in 2.4
http://commons.wikimedia.org/wiki/File:Cell_membrane_detailed_diagram_en.svg

6. The Mitochondrion (pl. Mitochondria)
• The ‘power house’ of the cell
• Has a smooth outer membrane and
a folded inner membrane
• Where aerobic respiration occurs in
the cell
More in 3.7 and 8.1
Mitochondria in mammalian lung cells
Remember:
Where else do we see loops of DNA?
How does the size of a mitochondrion
compare with an average prokaryote?
The implications of the answers to these
questions are in Option D: Evolution
http://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en.svg
http://commons.wikimedia.org/wiki/File:Mitochondria,_mammalian_lung_-_TEM.jpg

7. Rough Endoplasmic Reticulum
Spot the
difference?
Smooth Endoplasmic Reticulum
http://images.wellcome.ac.uk/

8. The ‘spots’ are the
difference!
The Rough Endoplasmic
Reticulum is peppered with
ribosomes that give it the
rough appearance
It is where protein synthesis
occurs
more in 3.5 and 7.4

9. The (free) Ribosome, the
molecular machine
responsible for protein
synthesis
much, much more in 3.5 and 7.4
A ribosome on
the sculpture
“Waltz of the
Polypeptides” at Cold Spring Harbor Laboratory
http://www.flickr.com/photos/cryo_mariena/6033827307/sizes/m/in/photostream/

10. I shall name it………
The internal reticular apparatus!!
Pretty catchy… no?*
Camillo
Golgi *Everybody thought that was a terrible
name, so they called it the Golgi
apparatus instead
http://commons.wikimedia.org/wiki/File:C_Golgi.jpg
http://commons.wikimedia.org/wiki/File:Golgi_in_the_cytoplasm_of_a_macrophage_in_the_alveolus_(lung)_-_TEM.jpg

11. The Golgi Apparatus is a flattened
stack of membranes responsible
for the packaging and delivery of
proteins
http://en.wikipedia.org/wiki/File:Nucleus_ER_golgi.svg

12. Lysosomes are simple, membrane-bound organelles
full of enzymes that digest engulfed bacteria and
viruses and large molecules
for recycling.
http://commons.wikimedia.org/wiki/File:Lysosome.jpg

13. Image from an amazing site by teacher Andrew Brown
http://www.tokresource.org/tok_classes/biobiobio/biomenu/eukaryotic_cells/index.htm

14. 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells.
Rough Endoplasmic Reticulum
Mitochondrion
Smooth Endoplasmic Reticulum

15. What can you see?

16. 2.3.4 Compare prokaryotic and eukaryotic cells
Compare Give an account of similarities and differences between
two (or more) items, referring to both (all) of them throughout
Prokaryotic Eukaryotic
Small cells Relatively larger cells
Always unicellular Some multicellular, some unicellular
No nucleus: DNA a ‘naked’ loop in the DNA in chromosomes in a membrane-
nucleoid region bound nucleus
Ribosomes smaller (70s) Ribosomes larger (80s)
No mitochondria, respiration in cell Mitochondria, where aerobic respiration
membrane and mesosomes occurs
Cell division by binary fission Cell division by meiosis or Mitosis
Reproduction asexual (some gene Reproduction Sexual or asexual
exchange can occur via conjugation)
Table modified from Click4Biology

17. 2.3.5 State three differences between plant and animal cells
State: Give a specific name, value or other brief answer without
explanation or calculation.
Plants Animals
Have a cell wall Don’t have a cell wall
Have chloroplasts in photosynthetic cells Don’t have chloroplasts anywhere
Carbohydrate stored as starch and plant
oils V. Carbohydrate stored as glycogen and
animal fat
Rigid Shape (due to cell wall) Flexible shape
Have a large permanent storage vacuole May have small, temporary vacuoles
http://www.flickr.com/photos/chubbybat/45407031/ http://www.flickr.com/photos/powi/749366522/

18. 2.3.6 Outline two roles of extracellular components
Bone cells have an
Outline:
extracellular matrix in
Give a brief
account or the interstitial spaces
summary. (between the cells)of
Got a banana? collagen and calcium
phosphate; which
together form the hard
bone.
http://www.flickr.com/photos/limonada/14705232/

19. The other form of
extracellular matrix is the
basement membranes
They exist in many tissue
types as a form of support
e.g. as the lining in blood
vessels
You may already know about the
glomerulus in the kidney. A basement
membrane is integral to ultrafiltration
there.
More in HL 11.3
http://commons.wikimedia.org/wiki/File:Gallbladder_cholesterolosis_low_mag.jpg

20. As well as extracellular
matrices in animals,
plant have extracellular
components….
Cell Walls
They are made of cellulose and provide
structure, support and protection. They
maintain cell shape and
prevent turgor pressure
from rupturing the cell
http://www.flickr.com/photos/ah_pao/2590017159/

21. Further information:
Three of the best sites for
IB-specific Biology
information. The top link
takes you to the PPT by
Stephen Taylor