Download Chapter 2Key Questions Activity

Key Questions
1 What is a cell?
Answers to be matched with the question
The cell wall in fungi is composed of chitin, whereas the cell wall of plants is composed of
cellulose.
2 List the three components of the cell theory.
To prepare a specimen to be viewed under a electron microscope the specimen must be fixed,
embedded (e.g. in epoxy resin), and sectioned and stained (for transmission microscopes) or
coated with gold (for scanning microscopes).
3 Before the cell theory, what alternative theory existed?
Who disproved this earlier theory?
Light microscopes use a beam of light, and objects are viewed in colour at low to high
resolution. An electron microscope uses a beam of electrons, and objects are viewed in black
and white at resolutions that can be thousands of times greater than can be achieved with a
light microscope.
4 Cells can be divided into two main groups. Name these
groups
and list the features that distinguish them.
A light microscope can be used to view living cells in colour. Preparation time is usually quick
and simple. Stains can be used to highlight different components of cells in colour.
5 Name some features that all cells have in common.
Kingdom Animalia (e.g. humans, kangaroos, parrots, flatworms and sponges); Kingdom
Plantae (e.g. eucalypts, conifers, grasses, mosses); Kingdom Fungi (e.g. yeasts, mushrooms
and bread moulds); and Kingdom Protista (e.g. algae, slime moulds, Euglena and amoebas).
See distinguishing characteristics in Table 2.1, page 26 of Heinemann Biology One.
6 How is the cell wall in fungi different to the cell wall in
plants?
Complex protein structures have been determined (e.g. antibodies) and also the technology is
central to drug design and development. Tissue samples have been analysed to identify
disease.
7 Name the kingdoms comprising organisms with eukaryotic
cells.
Give an example of each kingdom, and explain how you would
distinguish each kingdom.
8 A scientist made the following observations of a cell: it
photosynthesised; it had a plasma membrane within a cell wall;
it had no nucleus. What kingdom would this cell belong to?
Explain your answer.
The previous theory was spontaneous generation, which said that life arose spontaneously.
This was disproved by Louis Pasteur's experiments.
The smallest functional unit of life. A building block of multicellular organisms
9 Explain the differences between a light microscope and an
electron microscope.
All cells have a plasma ( cell) membrane, this contains the cytoplasm and within this is DNA a
nucleic acid, not all cells have DNA membrane bound, in a nucleus
10 What are the advantages of a light microscope over an
electron
microscope?
The synchrotron allows matter to be studied with greater accuracy and precision than has
ever been possible, down to the atomic scale. It enables information on the behaviour of
proteins to be obtained in a much shorter time compared to previous methods.
11 Outline the preparation necessary to view an object under
an
electron microscope.
• All organisms are composed of cells ( and the products of cells).
• All cells come from pre existing cells.
• The cell is the smallest living organisational unit.
12 What advantages in structural biology are gained by a
synchrotron?
Prokaryotes are small cells of Kingdom Monera. They lack membrane bound organelles and
have their requirements in the cytoplasm. Eukaryotes are larger cells, are capable of being
multicellular and have membrane bound organelles with specific functions
13 What advances have been made in science with the help of
synchrotron technology?
Kingdom Monera. Photosynthesis rules out Kingdoms Animalia and Fungi. The presence of a
cell wall is further evidence that it is not an animal cell. The lack of a nucleus also rules out
Protista and Plantae. The cell must be a photosynthetic moneran — a cyanobacterium.