CHAPTER FOUR

LIFE PROCESSES IN LIVING THINGS I

Objectives
The student will be able to:
o Describe the structure of Amoeba, Paramecium and Euglena.
o Explain the life processes of Amoeba, Paramecium and Euglena.
o Explain nutrition and reproduction in Spirogyra and Rhizopus.
o Identify Mosses and Ferns.
o Describe the external features of mosses and ferns.
o Explain nutrition and reproduction in mosses.
o Outline the reproduction in ferns

AMOEBA PROTEUS pseudopodium

Kingdom: Protoctista
plasmagel
Phylum: Rhizopoda
Habitat: Amoeba can be found in ponds, plasmasol
ditches, shallow muddy and in damp soils.
food nucleus
Structure vacuole
❖ Amoeba is a unicellular organism. contractile
❖ It has a jelly-like body with no definite vacuole
shape surrounded by a thin semi granule
permeable membrane.
❖ The body consists of protoplasm made up cell membrane
of the nucleus and the cytoplasm. Structure of Amoeba proteus
❖ The cytoplasm is made up of outer clear
layer, called ectoplasm or plamagel and Nutrition
more fluid, dense inner layer called ✓ Amoeba feeds on smaller organisms like
endoplasm or plasmasol. bacteria, plankton and diatoms.
❖ The endoplasm contains food vacuoles, ✓ It obtains its food through phagocytosis.
contractile vacuoles and a dense nucleus. It engulfs the food together with water
A food vacuole consists of partly digested with its pseudopodia to form food
food particles surrounded by bubbles of vacuole.
water. ✓ Enzymes are released from the cytoplasm
❖ A ‘false feet’ or pseudopodia projects into the food vacuole to digest the food.
from the body surface. ✓ The soluble end product diffuses into the
❖ Amoeba does not have constant shape. Its cytoplasm. The unwanted waste is
shape keeps changing by the formation of released through the cell membrane by a
pseudopodia process called exocytosis.
 Carbon dioxide produced from
contractile vacuole pseudopodia
nucleus closing around respiration diffuses out into the
prey surrounding water.

Movement
• Amoeba moves by using pseudopodia or
"false feet". It moves by controlling the
flow of its cytoplasm forming extensions
or projections called pseudopodia
(singular: pseudopodium). The
microscopic alga
food vacuole (e.g.Chlamydomonas) pseudopodia grow in the direction that
the Amoeba will like to move and at the
Amoeba engulfing its prey same time withdraw pseudopodia
elsewhere.
Irritability
 Amoeba responds to environmental Osmoregulation
conditions. Response to the stimuli is ➢ The cell membrane is semi permeable
called taxis (movement). Amoeba reacts and water continually diffuses into the
to light, temperature, various substances, cell by osmosis. The contractile vacuole
and other irritants. It moves towards a removes the water which diffuses into the
weak light but avoids powerful ray of organism. The contractile vacuole
light. Amoeba avoids adverse conditions quickly contracts expelling the liquid in it
for example, insufficient food, water or into the surrounding water. The cycle is
pond drying. The body is rounded, and it repeated and this process regulates the
goes into a resting state called a cyst. amount of water present in the cytoplasm.

Importance of osmoregulation
Excretion
✓ Osmoregulation enables Amoeba to
✓ Waste products of metabolism in Amoeba
maintain osmotic balance.
include carbon dioxide, urea and
✓ It also prevents Amoeba from bursting.
ammonia. These waste products diffuse
out through the cell membrane. Others
Reproduction
are dissolved in water in contractile
Binary Fission:
vacuole and they are eliminated together
Amoeba reproduces asexually by binary
with excess water.
fission. The process takes place in favourable
Respiration condition. Amoeba stops moving and rounds
□ Amoeba has no special structures for off. The nucleus first constricts and divides
respiration. Gaseous exchange in amoeba followed by division of the cytoplasm. The
is simply through the process of daughter amoebae separate into two identical
diffusion. It obtains oxygen for cells.
respiration from the surrounding water by
diffusion through the cell membrane.
 Multiple Fission or Sporulation
The process takes place in unfavourable
condition, such as insufficient food, oxygen,
water or temperature. Amoeba secretes a hard
resistant cyst around itself. This process is
term as encystment. This cyst helps the
organism to survive adverse conditions.
Within the cyst the nucleus divides into many
parts followed by division of the cytoplasm
to form large numbers of amoebae. When
conditions become favorable, the cyst break
open and numerous amoebae come out in
Binary fission in Amoeba water.

PARAMECIUM
Kingdom: Protoctista
Phylum: Ciliophora
Habitat: muddy polluted, fresh water ponds and ditches
cilia meganucleus micronucleus

contractile vacuole
radiating canal
plasmagel contractile
vacuole
plasmasol
food vacuole

pellicle
food substance
anal pore cytostome gullet Oral groove
Paramecium caudatum
Structure □ Beneath the pellicle are oval bodies
□ It has a fixed slipper-shaped and is about called trichocysts used for defense.
0.24mm in length. □ The whole body is covered by tiny, hair-
□ It has transparent body (with rounded like protoplasmic threads called cilia.
anterior end and pointed posterior end), □ The cilia are inter-connected at their basal
enclosed by elastic membrane called bodies by fine fibers called neuronemes.
pellicle. □ The cytoplasm is divided into outer layer
(plasmagel) and inner layer (plasmasol).
□ It has two nuclei; the large and bean- forward or backwards smoothly.
shaped nucleus called meganucleus and Paramecium rotate on its long axis during
the smaller spherical nucleus called movement.
micronucleus which lies just close to the
meganucleus. Osmoregulation
□ There are two star shaped contractile • Osmoregulation is carried out by
vacuoles lying at the anterior and contractile vacuoles, which actively expel
posterior end. water from the cell which frequently
□ The ventral side of the body is hollowed absorbed by osmosis from its
out to form oral groove which leads into surroundings.
the gullets in the endoplasm. The gullet,
Nutrition
in turn leads into the cytosome (mouth
 Paramecia feed on bacteria, algae,
pore).
yeasts, diatoms and decaying organic
Excretion matter.
o Waste products such as carbon dioxide,  The cilia beat frequently to create water
urea and ammonia are diffuse through the current, which drives food along the oral
cell membrane. groove into the cytostome where they are
o Excess water are carried out by the two ingested in a food vacuole.
contractile vacuoles that work  Food vacuole circulate through the
alternatively. cytoplasm, and enzymes are secreted into
the food vacuole to breakdown the
Locomotion
content.
o Paramecium propels itself by whiplash
 The digested nutrients are then absorbed
movements of the cilia. The cilia move
into the cytoplasm. The undigested food
forwards and backwards acting as tiny
is released through a special opening
paddles. The cilia propel the organism
called anal pore.

food vacuole forming

path of food
vacuole

anal pore
food particles drawn gullet
in by ciliary current

Nutrition in Paramecium
Respiration develop into the meganucleus and
□ Paramecium requires oxygen to break micronucleus.
down and absorb food in the cytoplasm.
Oxygen diffuses into the cytoplasm and Adaptation
carbon dioxide produced as a result of  It possesses numerous cilia for
this process, diffuses out in the reverse locomotion
direction  It possesses contractile vacuole for
osmoregulation
Reproduction  It possesses a pellicle, which gives it a
Reproduction involves Asexual and Sexual definite shape
reproduction.  It possesses trichocyst, which are used for
❖ Asexual reproduction: Paramecium defense and attack.
reproduces asexually, by binary fission.  The presence of oral groove enables it to
The macronucleus splits and the feed.
micronucleus divide and move to
opposite ends of the organism. The cell
then divides transversally to produce two EUGLENA
new paramecia. Kingdom: Protoctista
Phylum: Euglenophyta
❖ Sexual reproduction: under Habitat: lakes, ponds, ditches, contaminated
unfavourable conditions paramecium stagnant water and slow moving streams.
undergoes sexual process known as
conjugation. The two organisms Structure
involved in conjugation are called  Euglena is unique organism with both
conjugants. During conjugation, two plant and animal features.
paramecia come together and unite at  It is unicellular with a body covered with
their oral grooves. The meganuclei a thin, elastic and flexible pellicle,
disappears, and the micronucleus divides enclosing a cytoplasm.
into four. Three of the four nuclei of each  The cytoplasm consists of thin outer clear
conjugant disintegrate and the remaining ectoplasm (plasmagel) and an inner more
one divides into two active and passive fluid, granular endoplasm (plasmasol).
nuclei. Exchange of active nuclei occurs  It has a gullet with reservoir base located
between the two conjugants. Fusion at the anterior. A long flagellum and short
occur after interchange of nuclei to form one arising from the base of reservoir.
a zygotic nucleus. The paramecia  At the base of the long flagellum is
separate from each other and the zygotic photoreceptor covered by a red pigment
nucleus in ech divides thrice by mitosis to spot called eyespot. This enables euglena
form eight nuclei. Each conjugant to repond positively to light.
undergoes two binary fission to produce  Within the cytoplasm lies a stellate
four paramecia. Each daughter chloroplast, eyespot at the anterior end, a
paramecium has two nuclei which contractile vacuole near the reservoir,
 paramylum granules and a nucleus placed
towards the posterior end.
stellate chloroplast paramylum granules
reservior
nucleus
pigment spot

pellicle gullet

cytoplasm

myoneme light-sensitive flagellum

swelling
Contractile vacuole
Structure of Euglena

Movement dioxide produced as a result of respiration

• Euglena moves by means of its flagellum. is released outwards.
It moves by lashing the flagellum. It
Irritability
moves in a zigzag path whiles rotating on
□ Euglena possesses a red eye spot
its axis, in a movement described as
sensitive to light (photosensitive). It
euglenoid.
enables Euglena to move towards light
Nutrition needed for photosynthesis. When it
➢ Autotroph: Euglena possesses comes into contact with unfavorable
chloroplast and feeds by means of stimulus it quickly moves away from it.
photosynthesis. Energy trapped from the
Reproduction
sun is used to synthesize glucose from
✓ Euglena reproduces asexually by binary
water and carbon dioxide. Excess glucose
fission. It begins with division of the
is converted into starch and stored in the
nucleus, followed by the longitudinal
paramylum granules.
division of the cell itself.
➢ Heterotroph: Euglena without
✓ In low moisture conditions, or when food
chloroplast ingests decaying plant and
is scarce, Euglena forms a protective wall
animal remains through the gullet and
around itself as in amoeba and lies
digest them in the reservoir.
dormant. The content of the cyst divides
Respiration into two, four or more euglenae when
❖ Exchange of gases occurs between the favorable conditions returns.
cell and the surrounding water by
Plant-Like Features of Euglena
diffusion. Oxygen diffuses into the
 It has chloroplast containing chlorophyll
cytoplasm through the pellicle. Carbon
used to absorb light.
 Paramylum granules for starch storage
 Pyrenoids Adaptation
 Definite shape  The body is protected by a stiff pellicle.
 It has contractile for osmoregulation.
Animal-Like Features of Euglena  It possesses locomotory organ
 Gullet for feeding (flagellum) for movement.
 Has flagellum for locomotion  Presence of chloroplast for
 Myonemes for movement photosynthesis
 Has pellicle that gives it a definite shape  It has paramylum granules for starch
 Has eye spot to detect light intensity storage.
 Has contractile vacuole for  It possesses eyespot for light sensitivity.
osmoregulation and excretion

SPIROGYRA
Kingdom: Proctoctista
Phylum: Chlorophyta
Habitat: Freshwater, ponds, ditches, and slow moving streams.

cytoplasmic thread nucleus

mucilage

pyrenoid
vacuole
spirally
chloroplast

Cellulose cell
wall
Structure of Spirogyra

Structure extends as a thread into the center of the

o Spirogyra is a green free floating cell to enclose and suspends the nucleus.
filamentous alga. o The chloroplasts are ribbon shaped and
o It is un-branched with cylindrical cells spirally arranged in the cytoplasm. Each
connected end to end in long filaments. chloroplast contains several pyrenoids,
o The cell wall is two layered; the outer which stored starch.
wall composed of thick, slimy, protective
mucilage while the inner wall is of Nutrition
cellulose. ➢ Photosynthetic autotroph: makes its
o The cytoplasm forms a thin lining own food using energy from sunlight.
surrounding a large vacuole. It also The chloroplast contains chlorophyll
which absorbs energy from sunlight for
 synthesizing glucose. Excess glucose are Sexual Reproduction (Conjugation)
converted to insoluble starch and stored This process occurs under adverse conditions
in the pyrenoids. such as drought or cold. Conjugation requires
association of two different filaments called
Reproduction conjugants lined side by side. One cell each
Asexual Reproduction: occurs in two from opposite lined filaments develop
forms; binary fission and fragmentation. protrusions known as conjugation tubes.
 Binary Fission: This occurs frequently Conjugation tubes elongate and fuse, to make
when conditions are favourable. The a passage called the conjugation canal. The
nucleus constricts and divides into two. A cytoplasm pulls free from the cell wall and
new cellulose cell wall develops the cell contents round off to form a gamete.
transversely to separate the two nuclei Gamete from one cell moves through the tube
and other cell structures. The two cells do and fuses with the other gametes to form a
not separate but grow to normal size zygote. A resistant wall develops around the
increasing the length of the filament. zygote to form a spore called zygospore. The
spore can survive adverse conditions and
 Vegetative Reproduction
when conditions become favourable, the
(Fragmentation): is another form of
resistant wall breaks open and a new
asexual reproduction. The filament
spirogyra filament grows out.
breaks into small lengths. Each fragment
becomes a new filament by cell division
and cell elongation.

1 2
Acting ‘male’
gamete

‘female’ gamete

protuberance growing cell content of male

toward opposite cell gamete moves across
3 4

zygote zygospore

fusion of male and

a zygote is formed and thick resistant
female gamete
wall formed around the zygote
 Adaptation
new filament 5  It’s protected by two layers of cell wall; an outer
cellulosic layer and inner pectin layer.
 Presence of ribbon like chloroplasts for synthesis
of glucose.
 Pyrenoids for starch storage.
germination of zygospore  Filament has root-like structures for adhering to
substratum.
 Each cell wall is surrounded by protective
mucilage which prevents desiccation.

RHIZOPUS (BREAD MOULD)

Kigdom: Fungi
Phylum: Zygomycota
Habitat: It lives on decaying organic matter. They are mostly found on moist bread or rotting
fruit, kept under warm and humid conditions.

sporangium developing
sporangium
columella

Sporangiophores

mycelium

rhizoid stolon

Structure of Rhizopus

Structure ❖ The cell wall of the hypha consists of

❖ Rhizopus is eukaryotic, multinucleated chitin (complex protein and
and non-photosynthetic organism. carbohydrates).
❖ The body is made of fine thread-like ❖ The hypha contains a thin layer of
structures called hyphae (singular: cytoplasm which is multinucleated
hypha). The hyphae branch into a (several nuclei).
complicated network known as the ❖ The center of the tube of hypha is
mycelium. occupied by vacuole. Hyphae lack cross
 walls or septa, and therefore described as
□ Conjugation: It involves opposite
non-septate or aseptate.
mating (positive and negative) strains
There are three types of specialized
coming into contact. These strains grow
hyphae:
towards each other and meet by
❖ Stolons: are unbranched hyphae, which
developing protrusion called
grow horizontally on the substrate.
progametangia (singular:
❖ Rhizoids: are root-like structures. They
progametangium). The tips of the
anchor the fungus into its substrate,
progametangia swells and develops into
release digestive enzymes, and absorb
gametangia. The gametangia become
nutrients for the fungus.
separated from the rest of the hyphae by
❖ Sporangiophores: are the upright
forming a cross wall called suspensor.
hyphae which bear round reproductive
The walls between the two touching
structures called sporangia (singular:
gametangium dissolve allowing the two
sporangium).
multinucleate protoplasts to mix. The
Nutrition nuclei fuse in pairs forming several
➢ The mode of nutrition is saprophytic or diploid nuclei and later develop into a
saprotrophic, meaning is not capable of zygospore. A black thick-walled forms
synthesizing its own food and it depend around the zygospore. The zygospore can
on dead and decaying organic matter. The withstand adverse conditions. The wall of
rhizoids secrete hydrolytic enzymes onto the zygospore cracks and produces a
food substrate to break down complex young hypha with sporangium containing
molecules into simpler and soluble spores.
substances. The end products are gamatangia
progamatangia suspensor
absorbed into the body by diffusion. This
method of digestion is described as
extracellular digestion. (+) strain
Reproduction
(-) strain
Rhizopus is able to reproduce both asexually
and sexually (conjugation)
□ Asexual reproduction: it occurs when 1 2
fusion of +
environmental conditions are favourable. and - nuclei zygospore
The sporangiospores or spores are
produced inside a spherical structure
called sporangium. Sporangium absorb
water from atmosphere, swell and burst to
release or liberate the spores. The spore
are dispersed by wind and can grow into
new mycelia when settle on suitable
3 4
substrate (such as damp bread).
 Adaptation
 Rhizoids for anchorage and nutrients
zygospore wall absorption.
breaks open  Sporangiophore which support
sporangium.
 Spores or sporangiospores for asexual
reproduction and colonizing new habitat.
 Sporangium which support and protect
5 the spores.
Sexual reproduction in Rhizopus

MOSSES AND FERNS

MOSSES
Kingdom: Plantae
Division: Bryophyta
Class: Musci
Habitat: damp soil, tree bark, rocks, or concrete.
E.g. Brachymenium, Funaria

Structure

capsule Mosses are small non-vascular plants and therefore lack tissue for
transporting water and nutrients. They do not have true roots, stems,
or leaves because they lack vascular tissue. Rhizoids are root-like
spores structures that anchor them to their substrate and absorb water and
seta nutrients. The leaves are simple, spirally arranged and only a single
cell thick with no cuticle, stomata or internal air spaces. The rhizoids,
leaf
stems and leaves together constitute the gametophyte. At a in life of
moss, the gametophytes produces a stalk called seta, with a capsule
having a cap called calyptra at its tip. This constitute sporophytes.
stem The spore-bearing sporophyte is dependent on the gametophyte, that
is, it derives its nutrition from the gametophyte. The gametophyte is
independent. Bryophytes are generally restricted to moist areas
rhizoids because the sperm are flagellated and therefore require at least a film
of water to swim to the egg.

Life Cycle
The life cycle of Bryophytes is described as alternation of generation. It’s a life cycle of an
organism, where asexual spore producing (sporophyte) generation alternates with a sexual gamete
producing (gametophytes) generation.
The moss life-cycle starts with a haploid spore that germinates to produce a branching filamentous
or thalloid structure called protonema (plural: protonemata). The protonema grows into green
gametophyte that is structurally differentiated into rhizoids, stems and leaves. The tips of the
gametophyte stems or branches develop sex organs of the mosses. The female organs are known
as archegonia (sing. archegonium). The male organs are known as antheridia (sing. antheridium).
The archegonium produces eggs called oosphere and antheridium produces biflagellate sperms
called antherizoids,
In the presence of water, sperm from the antheridia swim to fertilize the egg in the archegonium,
to form a zygote. The zygote develops into sporophytes. The sporophyte body comprises, a
capsule with a cap called the calyptra, a long stalk, called a seta and a foot embedded in the
gametophyte tissue. Mature capsule undergoes meiosis to produce haploid spores. The capsule
burst to release the spores, which germinate to produce a branching protonema.

calyptra
Meiosis
capsule
leafy
spores
gametophyte
sporophyte

seta
protonema
female
gametophyte
male (1n)
gametophyte gametophyte
(1n)

embryo anteridium
sperm

sperm
egg
Fertilization egg
archegonium

archegonium
Life Cycle of the Moss
FERNS Life cycle
Kingdom: Plantae The spores develop in the sporangia, are
Division: Filicinophyta released and dispersed when the sporangia
Class: Pteropsida burst on ripening. Under favorable condition
Habitat: they grow mostly in moist habitat of moisture and temperature, each spore
on land or trunks of trees and palm trees. germinates into a small, flat, heart-shaped
E.g. silver-back fern (Pityrogramma), photosynthetic structure called prothalus (i.e.
Nephrolepis, Dryopteris. the gametophyte). The prothalus is anchored
to land by unicellular rhizoids. A matured
Structure prothalus bears the antheridia, the male sex
Fern has an underground stem called rhizome; organs and archegonia, the female sex organs
thin adventitious roots, which absorb water on its under-surface. The anteridia produce bi-
and mineral salts and prominent leaves, called flagellate sperms called antherizoids. Each
fronds. Fronds emerge from the rhizome as a archegonium produces a single egg called
coiled structure which gradually unrolls as oosphere. The sperm swims in a film of water
growth proceeds. Each frond is pinnately on the surface of the prothalus to fuse with the
compound, made up of several leaflets egg to form a zygote. The zygote grows into
(pinnae). The leaf lamina is covered with an embryo and eventually develops into fern
shiny cuticle which reduce the rate plant, the sporophytes. The gametophytes
transpiration. tissue decays and the sporophytes live
Asexual reproductive structure (Sporangia, independently
containing spores) develop on the under-
surface of the mature leaflets. Cluster of The life cycle of the fern plant follows the
sporangia called sori, are found at the leaflet pattern of alternation of generations. The
margins. A protective structure called an gametophyte of the fern plant is small and
indusium covers each sorus (plural: sori). The insignificant compared to the sporophyte.
stem, roots and leaves have well developed Therefore, the sporophyte generation is
vascular tissue. dominant. The gametophyte and sporophyte
are independent.
 sporophyte sorus
(2n)

indusium
m
frond sori
rhizome

Sporangium
(2n)
roots meiosis
spores
(1n)
sporophyte
(2n)
spore
germination
gametophyte
(1n) gametophyte
(1n)
root

sperm

Fertilization

egg
archegonium
Life Cycle of the Fern
SSCE/WASSCE/GCE PASS QUESTIONS AND ANSWERS
OBJECTIVE
Use the following phyla to answer question A. flagellum C. nucleus
1 and 2 B. pyrenoid D. vacuole
I. Rhizopoda III. Ciliophora
10. Moulds belong to phylum
II. Oomycota IV. Chlorophyta
A. Ascomycota C. Oomycota
1. Amoeba belongs to the phylum
B. Basidiomycota D. Zygomycota
A. I B. II C. III D. IV
11. Rhizopus has heterotrophic mode of
2. Which of the following pairs of phyla are
nutrition because it
closely related?
A. lives and land
A. I and II C. I and IV
B. possesses hyphae
B. I and III D. II and III
C. has chitin in its wall
3. The type of reproduction found in D. lack chlorophyll
rhizopus is
12. Which of the following is not true of
A. fragmentation C. budding
Rhizopus/Mucor
B. binary D. spore formation
A. it sensitive to temperature
4. Antheridium produces B. it can manufacture its own food
A. gemmae C. sperms C. it undergoes asexual and sexual
B. ova D. spores reproduction
D. it bears spores contain in sporangia
5. The biological relationship between the
bread and the blackish growth referred to 13. Which of the following organisms is
A. Saprophytism C. commensalism multicellular in structure?
B. symbiosis D. parasitism A. Paramecium C. Spirogyra
B. Amoeba D. Euglena
6. Spirogyra reproduces sexually by
A. copulation C. binary fission 14. Which of the following structures present
B. fragmentation D. conjugation in euglena is also present in a typical plant
cell?
7. The locomotory structure in paramecium
A. Contractile vacuole C. Pellicle
is
B. Flagellum D. Chloroplast
A. cilium C. flagellum
B. cytoplasm D. pseudopodia 15. Amoeba can be found in all the following
habitat except
8. Which of the following differentiates
A. Damp soils C. ditches
Amoeba from other unicellular
B. Muddy ponds D. lagoons
organisms? Presence of
A. chloroplast C. flagella 16. Regulation of body fluids in Amoeba is
B. nuclei D. pseudopodia carried out by the
A. Plasmagel C. contractile vacuole
9. Euglena may be considered as animal
B. Pseudopodium D. cytoplasm
because it possesses
17. Alternation of generation occurs in 3. (SSCE 2001) (a) (i). With the aid of a
A. Euglena C. Crotalia labeled diagram, describe the structure of
B. Rhizopus D. Funaria euglena.
(ii) State two animal-like features of
18. Which of the following is not performed
euglena.
by both spirogyra and Rhizopus
(b)(i). Describe conjugation in spirogyra.
A. Respiration C. conjugation
(ii) What is the advantage of conjugation
B. Photosynthesis D. nutrition
of spirogyra?
19. Fungi do not make their own food
because Solution
A. food is absorbed through the mycelia (a) (i) & (ii) Refer to SSCE 1994
B. fungi grow on dead organic matter (b) (i) Conjugation in spirogyra
C. fungi lack chlorophyll Refer to notes
D. fungi may assist in the decay of food
(iii) Advantages
20. Ihe archegonium produces
 Gametes are protected as they are not
A. antherizoids C. oospheres
exposed to the environment.
B. germma D. spores
 Zygotes are protected
 Bring about recombination
Answers
1. A 6.D 11. D 16. C 4. (WASSCE, 2006 Q5) Outline the life
2. B 7.A 12. B 17. D cycle of a named bryophytes
3.D 8. D 13. C 18. B
Solution
4.C 9.A 14. D 19. C
Refer to SSCE 1993 Q2b
5.A 10.D 15. D 20. C

5. (WASSCE, 2008 Q1) (c) Explain the

THEORY process of osmoregulation in Amoeba.
1. (SSCE, 1993 Q2) (b) describe the life of
Solution
a moss plant.
(c) Osmoregulation in Amoeba
2. (SSCE, 1994) (a) List any three feature
The cell membrane is semi permeable and
that make euglena an animal.
water flows into the cell by osmosis. The
Solution contractile vacuole removes the water which
Refer to notes diffuses into the organism. It then contracts
expelling the liquid in it into the surrounding
Solution water. This process regulates the amount of
 Eye spot ♦ Gullet water present in the cytoplasm.
 Contractile vacuole ♦ Flagellum
 Body covered with pellicle 6. (WASSCE, 2008 Q5) (a) Describe the
life cycle of fern.
Solution Solution
The life cycle of a fern consists of two (i) Euglena or Chlamydomonas
alternating generation i.e. the sporophytes (ii) Refer to notes
and the gametophyte. The sporophyte is
dominant and diploid and produces spores in 8. (WASSCE, 2014) State two reasons
sporangia borne on the leaves. The spores are why bryophytes are confined to damp
haploid. The spores germinate into prothalus, habitat.
which constitutes the gametophytes. The (ii) Named three organisms that
gametophytes is an independent haploid reproduced conjugation
plant, and bears both male and female sex
organs i.e. antheridia and archegonia. The Solution
antheridium produces many antherizoids o Sexual reproduction of bryophytes
which are flagellated. The archegonium requires water or moisture through
produces only one oosphere (egg). The which the male gamete swims to the
antherizoids swim and enter archegonium. It female gamete.
fuses with the egg to form a zygote, which o They do not have true roots to absorb
remains in archegonium and develops into a minerals and water and therefore, absorb
new sporophyte. The sporophyte iniatially water all over their body surface by
depend on the prothallus for nourishment. simple diffusion and osmosis.
o The plant surface lacks a cuticle which
7. (WASSCE, 2014) (i) Name one enables it to absorb water through its
organism that exhibits both plant and surface.
animal features o They are non-vascular; hence they have
(ii) State four animal features and two direct contact with water.
plant features possessed by the organism
(ii) Organism reproduce by conjugation
named in (c) (i) above.
Paramecium, Zygnema, Chlamydomonas,
spirogyra, Rhizopus/mucor