Uses of Plant Parts

Read p 566 – 569 Do p 569 # 1 - 4

Plant Part Uses

Plant parts evolved to serve the needs of the plant, but many other organisms depend on the plant parts as well. Here are 7 important plant part uses.

1. Fragrances

• Plants use scents to attract pollinators.• Humans use plant fragrances for perfumes

and flavourings

Jasmine Plant

2. Poisons• Plants produce poisons to protect themselves

from predation or to kill predators.• Humans have used the poisons for hunting or for

drugs like digitalis from the foxglove which is used as the heart medicine digoxin.

3. Sugars and Starches• The glucose produced by photosynthesis in the

chloroplasts is a way to store energy from the sun.

6CO2 + 6 H2O + light C6H12O6 + 6O2

• The plant extracts the energy from glucose through cellular respiration in mitochondria. C6H12O6 + 6O2 6CO2 + 6 H2O + ATP energy

• The plant stores excess sugar as starch.• Animals consume plants to get the sugars and

starches for their cellular respiration.

4. Cellulose

• Cellulose makes plant cell walls tough.• Plants make cellulose by bonding many

glucose together in a special way.• Grass eating animals can digest cellulose for

energy but not humans.• We use cellulose to make paper, clothing and

as lumber for housing.

Clear Cutting for Pulp and Paper and Lumber

5. Oils and Lipids• Plants often store excess energy as oils in the

seeds, which will be food for the embryonic plant

• Humans grind the seeds to extract oils for foods and beauty care products

Products from Milling Corn!

6. Proteins

• Plants absorb nitrogen (as nitrates) from the soil and use it to make amino acids.

• Amino acids are joined to make proteins to be used for enzymes, structures cell organelles and carrier molecules

• Humans and other animals eat plants to get amino acids to make our own proteins.

• Humans can NOT use soil nitrogen to make amino acids.

• For vegetarians to get all the necessary amino acids they need to eat starchy foods with legumes like beans, nuts and lentils.

7. Vitamins and Minerals• Plants need vitamins and minerals too for

healthy cell function.• Vitamin C in citrus fruits is made for the plant

not for us like the potassium in bananas.• The best way for humans to be well nourished

is to eat a range of bright coloured fruits and vegetables.