Page 87 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

Activity 5.3: Investigating the bread, cassava, pawpaw, and tomato.
structure of yeast cells Examples of organisms in this group
include mucor and black bread mould.
Materials: Dry yeast, water, methylene See Figure 5.15.
blue reagent, microscope, coverslips,
observed in yeast cells when READING ONLY
microscope slides, dropper, pencil, and Young sporangium Spores
notebook

Procedure
1. Dissolve some dry yeast cells in
water.
2. Using a dropper, place a drop of Mature sporangium
the yeast solution on a microscope Sporangiophore
slide and cover it with a coverslip.
3. Examine the specimen using the Stolon Mycelium
low-power objective lens of the Rhizoids
microscope. (a)
4. Identify some yeast cells.
5. Describe the structures you have
FOR ONLINE
Sporangium
using the high-power objective
lens of the microscope. Sporangiophore
6. Compare your results with Figure Stolon Mycelium
5.14. Rhizoids

(b)
Phylum Zygomycota
The members of this group are known Figure 5.15: Examples of zygomycetes
as zygomycetes because they have (a) black bread mould (b) mucor
sexual spores known as zygospores.
Zygospores are produced in the Characteristics of zygomycetes
structures called zygosporangia. They (a) They are multicellular.
also have asexual spores known as (b) They are saprophytic, growing on
sporangiospores, which are produced decaying organic materials.
in the structures called sporangia. (c) They reproduce sexually through
Zygomycetes grow as a mass of zygospores or asexually through
white or dark tiny threads and feed on sporangiosphores.
rotting or decaying food materials like (d) Have hyphae without cross walls.

Student’s Book Form One Student’s Book Form One 81

15/10/2024 09:24:32
Biology FORM 1 new.indd 81
Biology FORM 1 new.indd 81 15/10/2024 09:24:32