Algae

Question 1

Algae are

Answer 1

chlorophyll-bearing
simple, thalloid
autotrophic
largely aquatic (both fresh water and marine)

Question 2

They occur in a variety of other habitats:

Answer 2

moist stones, soils and wood

Question 3

Some of them also occur in association with

Answer 3

fungi (lichen)
animals (sloth bear)

Question 4

The form and size of algae is highly variable, ranging from

Answer 4

colonial - Volvox
filamentous - Ulothrix, Spirogyra
A few of the marines - kelps, form massive plant bodies.

Question 5

Vegetative reproduction is by

Answer 5

fragmentation

Question 6

Each fragment develops into a

Answer 6

thallus

Question 7

Asexual reproduction is by

Answer 7

the production of different types of spores, the most common being the zoospores.

Question 8

Zoospores are (a) and on germination gives rise to

Answer 8

(a) flagellated (motile)
(b) new plants

Question 9

Sexual reproduction takes place through

Answer 9

fusion of two gametes

Question 10

Isogamous

Answer 10

~ gametes are flagellated and similar in size ( Ulothrix) ~ non-flagellated (non-motile) but similar in size (Spirogyra)

Question 11

anisogamous

Answer 11

Fusion of two gametes dissimilar in size (Eudorina)

Question 12

oogamous

Answer 12

Fusion between one large, nonmotile (static) female gamete and a smaller, motile male gamete (Volvox, Fucus)

Question 13

Algae are useful to man in a variety of ways

Answer 13

True

Question 14

At least (a) carbon dioxide fixation on earth is carried out by algae through (b)

Answer 14

(a) half of the total
(b) photosynthesis

Question 15

Being photosynthetic, they increase

Answer 15

the level of dissolved oxygen in their immediate environment.

Question 16

They are of paramount importance as

Answer 16

primary producers of energy-rich compounds which form the basis of the food cycles of all aquatic animals.

Question 17

Many species of (a) are among the (b) species of marine algae used as food

Answer 17

(a) Porphyra, Laminaria and Sargassum
(b) 70

Question 18

Certain marine brown and red algae produce large amounts of (a) which are used commercially.

Answer 18

(a) hydrocolloids (water holding substances)
~ algin (brown algae)
~ carrageen (red algae)

Question 19

Agar, one of the
commercial products obtained from (a) (a)are used to

Answer 19

(a) Gelidium and Gracilaria
(b) grow microbes and in preparations of ice-creams and jellies

Question 20

Chlorella (a) is used as (b) even by space travellers

Answer 20

(a) a unicellular alga rich in proteins
(b) food supplement

Question 21

The members of chlorophyceae are commonly called

Answer 21

green algae

Question 22

The plant body of Chlorophyceae may be

Answer 22

unicellular, colonial or filamentous

Question 23

Chlorophyceae are usually

Answer 23

grass green due to the dominance of pigments chlorophyll a and b

Question 24

The pigments of chlorophyceae are localised in

Answer 24

definite chloroplasts

Question 25

The chloroplasts of chlorophyceae may be (a) in different species

Answer 25

discoid, plate-like, reticulate, cup-shaped, spiral or ribbon-shaped

Question 26

Most of the members of chlorophyceae have one or more storage bodies called (a) located in the (b)

Answer 26

(a) pyrenoids (b) pyrenoids

Question 27

Pyrenoids contain (a) besides (b)

Answer 27

(a) protein (b) starch

Question 28

Some chlorophyceae algae may store food in the form of

Answer 28

oil droplets

Question 29

Green algae usually have a

Answer 29

rigid cell wall made of an inner layer of cellulose and an outer layer of pectose

Question 30

Vegetative reproduction in green algae usually takes place by

Answer 30

fragmentation

Question 31

Asexual reproduction in green algae is by

Answer 31

flagellated zoospores produced in zoosporangia

Question 32

The sexual reproduction in green algae shows considerable variation in

Answer 32

the type and formation of sex cells (isogamous, anisogamous or oogamous.)

Question 33

Examples of green algae

Answer 33

Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara

Question 34

stored food of algae

Answer 34

starch

Question 35

Flagellar number and position of insertions of Green Algae

Answer 35

2-8, equal, apical

Question 36

Habitat of green algae

Answer 36

Fresh water, brackish water, salt water

Question 37

The members of phaeophyceae are commonly called

Answer 37

brown algae

Question 38

Brown Algae show great variation in

Answer 38

size and form

Question 39

Brown Algae range from

Answer 39

simple branched, filamentous forms (Ectocarpus) to profusely branched forms (kelps) which may reach a height of 100 metres.

Question 40

Brown Algae possess (pigments)

Answer 40

chlorophyll a, c, carotenoids and xanthophylls.

Question 41

Brown Algae vary in colour from (a) depending upon the amount of the (b)

Answer 41

(a) olive green to various shades of brown (b) xanthophyll pigment, fucoxanthin present

Question 42

Brown Algae stores food

Answer 42

as complex carbohydrates, which may be in the form of laminarin or mannitol.

Question 43

The vegetative cells of brown algae have a

Answer 43

cellulosic wall usually covered on the outside by a gelatinous coating of algin

Question 44

The protoplast of brown algae contains,

Answer 44

plastids, a centrally located vacuole and nucleus.

Question 45

In Brown Algae, The plant body is usually attached to the substratum by a

Answer 45

holdfast, has a stalk - the stipe leaf like photosynthetic organ – the frond.

Question 46

Vegetative reproduction of Brown Algae takes place by

Answer 46

fragmentation

Question 47

Asexual reproduction in most brown algae is by

Answer 47

biflagellate zoospores (pear-shaped) and have two unequal laterally attached flagella

Question 48

In Brown Algae, Sexual reproduction may be

Answer 48

isogamous, anisogamous or oogamous.

Question 49

In Brown Algae, Union of gametes may take place

Answer 49

in water or within the oogonium (oogamous species).

Question 50

Gametes of Brown Algae in sexual reproduction

Answer 50

The gametes are pyriform (pear-shaped) and bear two laterally attached flagella.

Question 51

Exampes of brown algae

Answer 51

Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus

Question 52

Habitat of Brown Algae

Answer 52

Fresh water(rare), brackish water, salt water

Question 53

The members of rhodophyceae are commonly called

Answer 53

red algae

Question 54

Why are rhodophyceae commonly called red algae?

Answer 54

because of the predominance of the red pigment, r-phycoerythrin in their body

Question 55

Majority of the red algae are

Answer 55

marine with greater concentrations found in the warmer areas.

Question 56

Red Algae occur in both

Answer 56

well-lighted regions close to the surface of water and also at great depths in oceans where relatively little light penetrates.

Question 57

The red thalli of most of the red algae are

Answer 57

multicellular

Question 58

Some of Red Algae

Answer 58

have complex body organisation.

Question 59

The food in Red Algae is stored as

Answer 59

floridean starch

Question 60

floridean starch is very similar to

Answer 60

amylopectin and glycogen in structure.

Question 61

The red algae usually reproduce vegetatively by

Answer 61

fragmentation

Question 62

The red algae reproduce asexually by

Answer 62

non-motile spores

Question 63

The red algae reproduce sexually by

Answer 63

non-motile gametes

Question 64

Sexual reproduction of red algae is (a) and accompanied by (b)

Answer 64

(a) oogamous (b) complex post fertilisation developments

Question 65

Examples of Red Algae

Answer 65

Polysiphonia, Porphyra, Gracilaria and Gelidium

Question 66

Habitat of red algae

Answer 66

Fresh water (some) brackish water, salt water (most)

Question 67

Cell Wall of Red Algae

Answer 67

Cellulose, pectin and poly sulphate esters

Question 68

Major pigments of Brown Algae

Answer 68

Chlorophyll a, c and fucoxanthin

Question 69

Major Pigments of Red Algae

Answer 69

Chlorophyll a, d and phycoerythrin