PRELIMINARY STAGE 2024
ROUND 5 - RIDDLE
RIDDLE
We are among the most primitive life forms on Earth.
We have been consumed as food or medicine by humans for centuries.
We contain various bioactive components such as phycocyanin, carotenoids, fibers, and plant sterols.
We are one of the photosynthetic prokaryotes found in aquatic ecosystems.
Our name is usually abbreviated as BGA.
ANSWER: Blue-Green Algae
EXPLANATION:
Blue-green algae, also called cyanobacteria, are photosynthetic prokaryotes found in water.
They are among the earliest life forms on Earth and contain bioactive compounds like phycocyanin, carotenoids, fibers, and sterols.
They have been used as food and in traditional medicine for centuries.
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PRACTICE QUESTIONS
1. RIDDLE:
We are algae.
We are eukaryotes.
We contain chlorophyll a and b, like land plants.
We store starch.
Chlamydomonas and Spirogyra belong to us.
We are the Chlorophyta, named for our colour.
Who am I?
ANSWER: GREEN ALGAE
EXPLANATION:
Green algae (Chlorophyta) have chlorophyll a and b and store starch.
2. RIDDLE:
We are algae.
We are mostly marine.
We contain chlorophyll a and c.
We store laminarin and mannitol.
Kelps and Fucus belong to us.
Fucoxanthin gives us our colour.
Who am I?
ANSWER: BROWN ALGAE
EXPLANATION:
Brown algae (Phaeophyta) owe their colour to fucoxanthin.
3. RIDDLE:
We are algae.
We are mostly marine.
Some of us live in deeper water than other algae.
We store floridean starch.
Agar and carrageenan come from us.
Phycoerythrin gives us our colour.
Who am I?
ANSWER: RED ALGAE
EXPLANATION:
Red algae (Rhodophyta) owe their colour to phycoerythrin.
4. RIDDLE:
I am a pigment.
I am an accessory pigment.
I am a carotenoid.
I absorb blue-green light.
I am found in diatoms and brown algae.
I give brown algae their colour.
Who am I?
ANSWER: FUCOXANTHIN
EXPLANATION:
Fucoxanthin is the brown accessory pigment of brown algae.
5. RIDDLE:
I am a pigment.
I am a phycobiliprotein.
I absorb green and blue light.
I help algae photosynthesise in deep water.
I am found in red algae and some cyanobacteria.
I give red algae their colour.
Who am I?
ANSWER: PHYCOERYTHRIN
EXPLANATION:
Phycoerythrin is the red pigment of red algae.
6. RIDDLE:
I am a pigment.
I am a phycobiliprotein.
I absorb orange and red light.
I am blue.
I am sold as a natural blue food colour made from spirulina.
I give blue-green algae their blue tint.
Who am I?
ANSWER: PHYCOCYANIN
EXPLANATION:
Phycocyanin is the blue pigment of cyanobacteria.
7. RIDDLE:
I am a substance.
I am a polysaccharide.
I come from red algae.
I melt when hot and set as a jelly when cool.
Bacteria cannot easily digest me.
I am used to make solid culture media in Petri dishes.
Who am I?
ANSWER: AGAR
EXPLANATION:
Agar from red algae is used for culture media.
8. RIDDLE:
I am a substance.
I am a polysaccharide.
I come from brown algae.
I thicken foods such as ice cream.
I form gels with calcium ions.
Dentists use me to take impressions of teeth.
Who am I?
ANSWER: ALGINATE
EXPLANATION:
Alginate from brown algae is a thickener and gelling agent.
9. RIDDLE:
I am an alga.
I am a brown alga.
I am one of the largest algae, growing up to about 50 m long.
I grow in cold coastal waters.
I form underwater forests.
I am anchored by a holdfast and held up by gas-filled bladders.
Who am I?
ANSWER: KELP
EXPLANATION:
Kelp is a large brown alga that forms kelp forests.