Saccharomyces cerevisiae is a unicellular fungus that is important in the brewing and baking industries.
Fig. 4.1 is a diagram of a transmission electron micrograph of S. cerevisiae.
Fig. 4.1
A student was asked to calculate the magnification of the image shown in Fig. 4.1.
The student began by measuring the length of the scale bar in millimetres using a millimetre ruler.
State what the student should do next to obtain the correct answer.
Smooth muscle is a tissue composed of smooth muscle cells. The cells contain cytoplasm packed with proteins that are involved in contraction and relaxation.
When viewed in longitudinal section (LS), smooth muscle cells are elongated and taper at both ends. This is known as a fusiform shape. Each cell has a central nucleus, which also appears elongated.
Fig. 1.1 is a diagram of a smooth muscle cell to show the fusiform shape.
Fig. 1.1
A student used a microscope fitted with a calibrated eyepiece graticule to estimate that the length of one smooth muscle cell was 250 micrometres .
Name the type of microscope slide that the student used to calibrate the eyepiece graticule.
In the immune system, a plasma cell develops from an activated B-lymphocyte. Mature plasma cells synthesise and secrete antibody molecules.
Fig. 4.1 is a diagram of a transmission electron micrograph of a plasma cell.
Fig. 4.1
The plasma cell can be seen in greater detail using an electron microscope compared with using a light microscope.
Describe the extra detail of the nucleus that can be seen using an electron microscope.
Explain why cell structures, such as ribosomes and the rough and smooth endoplasmic reticulum, cannot be seen using a light microscope.