Algae/01/024 - Xtics & Importances

Question 1

Which of the following is not a condition necessary for sexual reproduction in algae?
a) Suitable pH
b) High salinity
c) Optimum temperature
d) Presence of appropriate light

Answer 1

B

Question 2

Algae can have both unicellular and multicellular sex organs.

Answer 2

Algae possess sex organs that can be either unicellular or multicellular, depending on the species. This diversity allows for different reproductive strategies across various algae groups

Question 3

Describe the role of secondary pigments in algae and provide examples of these pigments.

Answer 3

Secondary pigments in algae, such as carotenes, xanthophylls, and phycobilins, play a crucial role in capturing light energy for photosynthesis. These pigments absorb light wavelengths that chlorophyll cannot, thus broadening the range of light that algae can use for photosynthesis. For example, carotenes and xanthophylls absorb blue and green light, while phycobilins absorb red, orange, and yellow light, making them particularly useful in low-light aquatic environments

Question 4

Discuss the significance of algae in aquatic ecosystems and their impact on environmental sustainability. Include examples of how algae contribute to or detract from ecosystem health.

Question 5

What is the primary basis for the classification of algae?
a) Habitat
b) Morphological and physiological features
c) Reproductive methods
d) Size and shape

Answer 5

b

Question 6

Explain the process of isogamy in algae and how it differs from other forms of sexual reproduction.

Answer 6

Isogamy involves the fusion between motile gametes that are similar morphologically but different genetically. The gametes are called isgametes and the organisms are isogamous.

Anisogamy involves the fusion of motile gametes that are both morphologically(different in size) and genetically different. The male gamete is typically smaller than the female gamete.

Oogamy involves the fusion of a **large, non-motile female gamete called the egg and a small, motile male gamete called the sperm.

Question 7

All algae have eukaryotic cells.

Answer 7

No, blue-green algae are prokaryotic

Question 8

membrane

Difference between eukaryotic and prokayotic?

Answer 8

Eukaryotic cells are complex cells contain a nucleus and other membrane bound organelles while prokaryotes are simple cells that lack a nucleus and other membrane-bound organelles

Question 9

Evaluate the potential of algae as a sustainable resource for biofuel production. Discuss the benefits and challenges associated with this application.

Question 10

Which type of algae has a cell wall composed of silica?
a) Green algae
b) Red algae
c) Diatoms
d) Brown algae

Answer 10

c

Question 11

Describe the process of vegetative reproduction in algae.

Question 12

Analyze the role of algae in carbon sequestration and its potential impact on climate change mitigation.

Question 13

What is the term for the plant body of algae that lacks differentiation into roots, stems, and leaves?
a) Thallus
b) Rhizoid
c) Frond
d) Blade

Answer 13

a

Question 14

Explain the concept of alternation of generations in algae.

Question 15

Discuss the ecological and economic importance of algae in marine and freshwater environments. Provide examples of how algae are used in various industries.

Question 16

Which of the following is not a form that algae can take?
a) Unicellular
b) Colonial
c) Filamentous
d) Vascular

Answer 16

d

Question 17

What are the primary pigments found in algae, and how do they contribute to photosynthesis?

Answer 17

• chlorophyll - green pigment that absorbs light during photosyntheses

Question 18

Blue-green algae exhibit sexual reproduction.

Answer 18

Nope.

Question 19

Critically assess the challenges and opportunities of using algae in wastewater treatment processes.

Question 20

Which of the following is a characteristic of blue-green algae?
a) Eukaryotic cells
b) Prokaryotic cells
c) Presence of flagella
d) Multicellular sex organs

Answer 20

b

Question 21

form, generation, secondary pigments, chlorophyll, habitat, thallus,euka

Describe 7 characteristics of algae

Answer 21

• They contain chlorophyll and make their own food; autotrophs
• have unicellular or multicellular sex organs
• have a plant body with no differentiation (roots,stems and leaves) called a thallus - thalli (they are thalloids)
• thallus is non-vascular (no vascular tissue)
• most are eukaryotic except blue-green algae which are prokaryotic
• habitat - aquatic (marine and freshwater), moist rocks and woods, on and within soils and in symbiotic relationships with fungi (lichen) and certain animals.
• may contain secondary pigments like carotenes (brown, yellow) and xanthophylls and phycobillins
• rigid cell wall composed of cellulose except diatoms whose cell wall is composed of silica
• exhibit ranges of alternation of generation (sporophyte - spore bearing and diploid & gametophyte - haploid and produces gametes)
• diff. forms - unicellular, colonial, filamentous, siphonaceous, parenchymatous…

Question 22

Compare and contrast the Euglena and Chlamydomonas

Answer 22

• both are unicellular and motile
• both are autotrophs
• Euglena ; 1 flagellum, Chlamyydomonas; 2 flagella

Question 23

Briefly describe each form in which algae organisms exist

Answer 23

Unicellular forms
- motile, non-motile or amoeba-like
- motile have flagella eg Chlamydomonas and Euglena
- non-motile have no flagellation nor cytoplasmic projections eg Chlorella
- amoeba-like have cytoplasmic projections and lack a rigid cell wall eg Rhizochrysis

Colonial Form
- Flagellate, non-flagellate
- Flagellate- motile flagellate cells come together to form simple colonies.In most cases, cells are covered in mucilage. eg Volvox
- non-motile cells form colonies.In some cases, covered in mucilage.

Filamentous
- branched, unbranched
- unbranched- formed by repeated division in one plane without separation of daughter cells.contain sheath and trichomes

• branched - 2 main types
  1.simple branching system attached to substratum with basal disc secreted from lowest cell.
  2.heterotrichous type
• basal attachment system of filaments giving rise to many upright branches.

Siphonaceous forms
- simple, unbranched vesicle & irregular branching system.

Parenchymous forms
- paper-like or tubular like thalli

Question 24

List the different forms in which algae exist

Answer 24

• unicellular
• colonial
• filamentous
• parenchymatous
• siphonaceous

Question 25

List the 3 different methods of asexual reproduction

Answer 25

1.Cell division
2.Fragmentation
3.Hormogone formation
4. adventitious thalli
5.tubers
6.bulbils
7.akinetes
8. zoospores
9. aplanospores

Question 26

Differentiate these methods of asexual reproduction :
1.Cell division
2.Fragmentation
3.Hormogone formation

Answer 26

1.Cell division
- the mother cell divides giving rise to new daughter cells that mature into new plants.
2.Fragmentation
- the plant body breaks into several parts called fragments.The fragments then develop into a new individual.
3.Hormogone formation
- the trichomes break into small pieces of 2 or more called hormogones
- each hormogone develops into a new plant.

Question 27

List 4 different structures involved in asexual reproduction

Answer 27

• adventitious thalli
• tubers
• bulbils
• akinetes
• zoospores
• aplanospores

Question 28

Describe the different structures involved in asexual reproduction.

Answer 28

1. Adventitious thalli
   - special structures of thalli called propagules help in vegetative propagation
2. Tubers
   -the plant’s underground storage structure that are rounded bodies filled with starch.They produce new plants.
3. Bulbils
   - are small bud-like structures that develop on rhizoids
4. Akinetes
   - these are thick-walled, dormant and often elongated spores that are formed during the dry szn.
5. Zoospores
   - formed from certain older cells of the filaments.
   - they escape from the mother plant and are able to develop into a new plant under favourable conditions.They are motile and may be bi or tetra flagellate
6. Aplanospores
   -spores formed from certain older cells of filaments that lost the means of motility and are surrounded by a cell wall( zoospores that have lost means of motility) Develop into a new plant under favourable conditions.

Question 29

gamy

What are three types of sexual reproduction exhibited in algae?

Answer 29

• isogamy
• anisogamy
• oogamy

Question 30

What are the necessary conditions for sexual reproduction of algae?

Answer 30

Takes place after considerable accumulation of food material
the climax of vegetative activity is over slowed.
Suitable pH is necessary.
Optimum temperature is necessary.
Presence of appropriate light.

Question 31

The primary classification of algae is based on which morphological and physiological features?

Answer 31

Pigment constitution of the cell.
Chemical nature of stored food materials
Nature and the number of flagella.
Chemical composition of the cell wall.
Presence or absence of a definitely organized nucleus in the cell.

Question 32

1. Describe the following life cycle patterns in algae
   a. Haplontic type
   b. Diplontic type
   c. Isomorphic type
   d. Heteromorphic type