Microorganisms 2 Algae

Question 1

What are algae?

Answer 1

Algae are simple, plantlike organisms that vary in size, shape, and habitat.

Question 2

What common feature do all algae have?

Answer 2

All algae have chlorophyll, which allows them to photosynthesize.

Question 3

How do algae reproduce?

Answer 3

Algae can reproduce sexually and asexually.

Question 4

Can you name examples of freshwater algae?

Answer 4

Chlamydomonas and Volvox are examples of freshwater algae.

Question 5

What type of algae are most commonly found in freshwater bodies?

Answer 5

Most green algae live in freshwater bodies.

Question 6

What are some environments where green algae can grow?

Answer 6

Some green algae are marine, while others grow on moist soil, tree trunks, or walls.

Question 7

What are the different forms of green algae?

Answer 7

Some green algae, like Chlamydomonas, are unicellular; others, like Spirogyra, form filaments; and some, like Volvox, live in clusters or form colonies.

Question 8

How does Oedogonium interact with aquatic plants?

Answer 8

Oedogonium fixes itself to aquatic plants.

Question 9

What is unique about diatoms?

Answer 9

Diatoms are mostly unicellular and have an infinite range of forms.

Question 10

What are the cell walls of diatoms made of?

Answer 10

Their cell walls are made of silica.

Question 11

What happens to diatom silica when they die?

Answer 11

When they die, the silica accumulates at the bottom of lakes, rivers, and seas to form siliceous earth.

Question 12

What are large masses of diatoms floating in the sea called?

Answer 12

Large masses of diatoms floating in the sea are called plankton.

Question 13

What colors can algae be besides green?

Answer 13

Not all algae are green; some are brown, while others are red.

Question 14

What causes the brown and red algae to mask the green color of chlorophyll?

Answer 14

Brown and red algae have additional pigments which mask the green color of chlorophyll.

Question 15

What is an example of a large brown alga?

Answer 15

Giant kelp can grow to a length of 30-60 m.

Question 16

What is the Sargasso Sea named after?

Answer 16

The Sargasso Sea owes its name to the brown alga Sargassum.

Question 17

Where do red algae primarily grow?

Answer 17

Red algae are mostly marine, growing in tropical and subtropical seas.

Question 18

What is the green scum found over wet soil and stagnant pools of water?

Answer 18

The green scum is formed by blue-green algae.

Question 19

What are blue-green algae more similar to?

Answer 19

These organisms are more like bacteria than like algae, so they are now called cyanobacteria.

Question 20

What type of algae are seaweeds mostly composed of?

Answer 20

Seaweeds are mostly brown algae.

Question 21

What is algin and where is it obtained from?

Answer 21

Algin is a gummy substance obtained from kelp. It is used to thicken ice creams, cosmetics, and shaving cream.

Question 22

What are the uses of algin?

Answer 22

Algin is used in the preparation of medicines and synthetic fibres.

Question 23

What substances are obtained from kelp?

Answer 23

Iodine and potassium are other substances obtained from kelp.

Question 24

What is agar and what is it made from?

Answer 24

Agar is a jellylike substance made from certain red algae.

Question 25

What is agar used for?

Answer 25

Agar is used to culture microorganisms and tissue in the laboratory.

Question 26

What are diatom shells used for?

Answer 26

Diatom shells are used to make glass, porcelain, ceramics, toothpaste, polishes, and filters.

Question 27

How are certain red algae consumed in China and Japan?

Answer 27

Certain red algae are dried and sold as papery sheets, eaten as vegetables, or used to make soups.

Question 28

What is the nutritional significance of algae?

Answer 28

Algae are rich in proteins and minerals and feed a host of aquatic organisms.

Question 29

What role do algae play in oxygen production?

Answer 29

Algae are the greatest providers of oxygen, accounting for 80% of the oxygen in air.

Question 30

What is eutrophication?

Answer 30

The enrichment of water bodies by plant nutrients.

Question 31

What often causes eutrophication?

Answer 31

Sewage and fertilisers draining into water bodies.

Question 32

What is an algal bloom?

Answer 32

An unnaturally rapid growth of algae that forms a thick layer over the surface of the water body.

Question 33

What effect do algal blooms have on light and oxygen?

Answer 33

They deprive other organisms of light and oxygen.

Question 34

What happens to algae when they die?

Answer 34

Bacteria acting on them use up more oxygen.

Question 35

What is the consequence of eutrophication on aquatic life?

Answer 35

Most other organisms living in the water body die.