Seminar B5 The cell: Organelles

1. Seminar B5 The cell: Organelles

Foundation Year Program
Seminar B5
The cell: Organelles
Introduction to Biology
2019-20

2. What is a Cell?

Foundation Year Program
What is a Cell?
• A cell is the basic unit of life
• All organisms are made of cells
• In the hierarchy of biological organization, the cell
is the simplest collection of matter that can be
alive
• Many forms of life exist as single-celled organisms
• More complex organisms, including plants and
animals, are multicellular
• Multicellular organisms are cooperatives of many
kinds of specialized cells that could not survive for
long on their own. However, the cell remains the
organism’s basic unit of structure and function
Introduction to Biology
2019-20

3. What do we call the study of cells?

Foundation Year Program
What do we call the study of cells?
• Cytology
• But… How can we study
cells?
• The most obvious way is by
observing them
• How can we observe cells?
Introduction to Biology
2019-20

4. Microscopy!!! What types of microscopy do you know?

Foundation Year Program
Microscopy!!!
What types of microscopy do you
know?
Introduction to Biology
2019-20

5. Microscopy Terms

Foundation Year Program
Microscopy Terms
• Magnification is the increase in an object’s
image size compared with its actual size.
• Resolution is a measure of the clarity of an
image. It is the ability of an instrument to
show two nearby objects as separate.
Introduction to Biology
2019-20

6. The Discovery

Foundation Year Program
The Discovery
• The progress in cell
discovery is associated
with the evolution of
microscopy.
• Larger cells were spotted
first while smaller
organisms had to wait for
the technology to be
developed.
Introduction to Biology
2019-20

7. Major events in cell biology & imaging

Foundation Year Program
Major events in cell biology & imaging
Introduction to Biology
2019-20

8.

Foundation Year Program
Microscopes reveal the world of the cell
The first microscopes were light microscopes.
In a light microscope
(LM), visible light
passes through a
specimen, then
through glass lenses,
and finally is projected
into the viewer’s eye.
Introduction to Biology
2019-20

9. Microscopes reveal the world of the cell

Foundation Year Program
What can we see with an LM?
Plant cell (non-leaf)
Introduction to Biology
Red blood cells
Plant cell (leaf)
2019-20

10. What can we see with an LM?

Foundation Year Program
Electron microscopes
• Beginning in the 1930s, scientists started using a
very powerful microscope called the electron
microscope (EM) to view the ultrastructure of cells.
• Instead of light, EM uses a beam of electrons.
• Electron microscopes can
– resolve biological structures as small as 0.2 nm
– magnify up to 1,000,000 times.
Introduction to Biology
2019-20

11. Electron microscopes

Foundation Year Program
What do they look like?
Scanning Electron
Microscope
Introduction to Biology
Transmission Electron
Microscope
2019-20

12. What do they look like?

Foundation Year Program
Electron Microscopy
Electron microscopes use a beam of electrons to view
very small objects. The beam acts in different ways:
It will either scan the surface or pass through the
samples.
Introduction to Biology
2019-20

13. Electron Microscopy

Foundation Year Program
SEMs vs TEMs
Scanning Electron
Microscope
Introduction to Biology
Transmission Electron
Microscope
2019-20

14.

Foundation Year Program
SEMs vs TEMs
Scanning electron
microscopes (SEMs) show
the detailed architecture
of cell surfaces.
Scanning electron micrograph of
Paramecium
Introduction to Biology
Transmission electron
microscopes (TEMs) show
the details of internal cell
structure.
Transmission electron micrograph of
Toxoplasma
2019-20

15. SEMs vs TEMs

Foundation Year Program
Your Task
• You are going to be given a set of cards with
pictures of 8 organelles.
• There are 6-8 pictures for each organelle.
• For each organelle:
– Collect the micrographs showing that organelle
– Identify the drawing that shows the organelle
– Choose the correct description
• Hint: you can spy on other groups to confirm
your ideas.
Introduction to Biology
2019-20

16. Your Task

Foundation Year Program
Let’s check your conclusions!!
Introduction to Biology
2019-20

17. Let’s check your conclusions!!

Foundation Year Program
Nucleus
Introduction to Biology
2019-20

18. Nucleus

Foundation Year Program
RER
Introduction to Biology
2019-20

19. RER

Foundation Year Program
SER
Introduction to Biology
2019-20

20. SER

Foundation Year Program
Golgi Body
Introduction to Biology
2019-20

21. Golgi Body

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Mitochondria
Introduction to Biology
2019-20

22. Mitochondria

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Chloroplast
Introduction to Biology
2019-20

23. Chloroplast

Foundation Year Program
Lysosomes
Introduction to Biology
2019-20

24. Lysosomes

Foundation Year Program
Centrioles/Flagella
Introduction to Biology
2019-20

25. Centrioles/Flagella

Foundation Year Program
Would you be able to tell which
photomicrographs are from…
• Light microscope?
Introduction to Biology
2019-20

26. Would you be able to tell which photomicrographs are from…

Foundation Year Program
Which photomicrographs are SEM?
Introduction to Biology
2019-20

27. Which photomicrographs are SEM?

Foundation Year Program
TEM?
• ALL THE REST!!!
• Thanks For Your Attention!!
Introduction to Biology
2019-20