Download Introductory Biology - Organelle Identification Practical (Week 8)

Introductory Biology - Organelle Identification Practical (Week 8)
The Ultrastructure of Cells
Students will need to work in pairs and share electron micrographs (numbered 1 to 15);
however, each student is to complete the worksheet. The Activity number corresponds to the
number on the electron micrograph! For example, Activity 3 will relate to the electron
micrograph no. 3. You may answer the questions in any order.
Activity 1
This is a section through a chloroplast. Notice that it has a “double membrane”. The
membranes inside the chloroplast form stacks (or grana) rather like a stack of shelves.
What substances would you expect to find “laid out” or “arranged” on these shelves?
…………………………………………………………………………………………….
What is the function of these substances?
…………………………………………………………………………………………….
Where in a plant would you expect to find cells containing large numbers of chloroplasts?
……………………………………………………………………………………………..
Activity 2
These two centrioles are composed of two groups of microtubules. One group of
microtubules is always orientated at right angles to the other. They are found just outside the
nucleus.
What cellular process are centrioles involved with?
……………………………………………………………………………………………….
Which of the following types of cells are centrioles found in? Circle the correct answer(s).
Animal cells
and/or
Plant cells
Activity 3
This is a section through the cell membrane of a cell with minute projections/folds of
cytoplasm called microvilli.
What advantage would microvilli give a cell?
…………………………………………………………………………………………………
Where in the human body would you find cells with microvilli? ……………………………..
Can you think of another place (organ)? ………………………………………………………
Tony Molyneux
-1-
24/3/2012
Activity 4
The main feature in this electron micrograph is the nucleus. The nucleus is usually the largest
organelle in a cell.
What is the approximate diameter of the nucleus in this cell? ……………………………..µm
Do you think that the scale bar in the bottom right hand corner of this micrograph is correct?
If not, what should it be? Explain your answer. ……………………………………………….
…………………………………………………………………………………………………..
What is the name given to the dark structure inside the nucleus? ……………………………..
What is the function of this dark structure? ……………………………………………………
………………………………………………………………………………………………….
Activity 5
This micrograph is of an Euglena sp., a unicellular aquatic organism.
Is it a prokaryote or an Eukaryote? Explain giving two reasons: (i) …………………………
(ii) …………………………………………………………………………………………….
What is organelle C? ………………………………………………………………………….
In what Kingdom does this organism belong? …………………………………………………
Activity 6
Is this electron micrograph showing you animal or plant cells? ………………………………
Give three reasons to support your answer above:
i)
………………………………………………………………………………………….
ii)
………………………………………………………………………………………….
iii)
………………………………………………………………………………………….
Activity 7
There is one cell in the centre of this micrograph.
Is it a plant cell or an animal cell? …………………………………………………………….
Give two reasons to support your answer above:
i)
…………………………………………………………………………………………..
ii)
…………………………………………………………………………………………..
Tony Molyneux
-2-
24/3/2012
Activity 8
What is the name of the organelle in the centre of this micrograph? ………………………..
Briefly describe its function: …………………………………………………………………...
…………………………………………………………………………………………………..
Activity 9
Is this a micrograph of a young plant cell or an old plant cell? ………………………………..
Explain your answer: …………………………………………………………………………..
…………………………………………………………………………………………………..
Activity 10
These are smooth muscle cells from muscle typical of smooth muscle surrounding gut and
blood vessels.
Draw a simple diagram of just one of the cells in the space below and label it with as many
structures as you can see.
Explain why there are large numbers of mitochondria in these cells? ………………………..
………………………………………………………………………………………………….
Tony Molyneux
-3-
24/3/2012
Activity 11
This micrograph shows a section through a single mitochondrion. Notice that it is surrounded
by a double membrane. The white “stripes” are invaginations or in-foldings of the inner
membrane, known as cristae. The cristae provide a large surface area for enzyme molecules
and for special carrier and “channel” proteins. A lot of transport both, passive and active,
going on here!!
What is the general term given to the chemical reactions that occur within the mitochondria?
………………………………………………………………………………………………..
There can be three possible answers: Who knows all three?? Prove it
What are the approximate dimensions (µm) of this organelle? ……………………………..
Activity 12
This micrograph is of a type of white blood cell (a neutrophil) which is generally known as a
phagocyte. Notice that it has a lobed nucleus!
What is the name of the organelles which are labelled by the X? ……………………………..
What is the function of these organelles labelled X? …………………………………………..
Phagocytes also contain large numbers of lysosomes, labelled L.
What is the function of a lysosome? ...........................................................................................
…………………………………………………………………………………………………..
Why do phagocytes contain large numbers of lysosomes? …………………………………….
…………………………………………………………………………………………………..
Activity 13
What is the name given to the organelles labelled Z? ………………………………………….
What is the function of this organelle? …………………………………………………………
…………………………………………………………………………………………………..
Activity 14
This micrograph is of the endoplasmic reticulum.
What is the name given to the small, dark organelles which can be seen along the membranes
of the endoplasmic reticulum? …………………………………………………………………
What is the function of these small dark organelles? …………………………………………..
What is the function of endoplasmic reticulum? ……………………………………………….
…………………………………………………………………………………………………..
Tony Molyneux
-4-
24/3/2012
Activity 15
This is a micrograph showing some cells.
What type of cell is being shown? ……………………………………………………………...
Give two reasons in support of your answer above.
i)
…………………………………………………………………………………………..
ii)
…………………………………………………………………………………………..
What process is being shown in this electron micrograph? ……………………………………
…………………………………………………………………………………………………..
Tony Molyneux
-5-
24/3/2012