Phloem and food storage
Leaves make sugar, but roots, fruits and seeds need it too. The phloem carries dissolved food around the plant, and the plant keeps the spare in storage organs like these yams. Animals store food too: in the liver and as fat.
By the end of this page you can
- Explain how the phloem is suited to carrying food, and why living things store food
- Name the food stored in plants and animals and where it is kept
- Trace sugar from a leaf to a storage organ
- Define translocation, source, sink, sieve plate and glycogen
- Explain how a sieve tube’s structure suits its job
Goals tick themselves off as you try the activities below.
Photo: Samsule2, CC BY-SA 4.0, via Wikimedia Commons. Cropped to the yams (people at the stall cropped out), resized, JPEG q66.
Every yam is a store of starch the plant made in its leaves and sent down through the phloem.
How often it shows up in past papers
Paper 1 counts come from our past-paper bank of CSEC Biology Paper 1s. Paper 2 is not included yet.
Move the food, then save some
Phloem carries food from where it is made to where it is needed. Tap each card.
Each store, its food
Tap each place to see what is stored there.
What is kept there?
Tap a place on the list to see its food.
A syllabus practical: test storage organs for their food. Iodine shows starch, Benedict’s solution shows sugar, and a grease spot on paper shows oil.
From leaf to store
Put these in order to follow sugar from a leaf to a sweet potato. Drag or tap each card into its slot.
Where is the sugar made?
Seven terms to know cold
Say what each term means before you flip the card. Structure answers need the sieve plate and the companion cell.
Six quick questions, then a real one
Pick an answer to see why it’s right or wrong.
Food is carried in the phloem mainly as
The end walls of sieve tube cells
Which of these is a sink?
Companion cells have many mitochondria because they
Animals store carbohydrate in the liver as
The food stored in a bean seed is used mainly to
exam style · 4 marks
Explain how the structure of phloem is suited to transporting food.
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Practice questions are written by My V.I.P. Academy. They are not official CXC papers.