Starch in leaves
To demonstrate the presence of starch in vegetable tissues.
Lo que aprenden los alumnos
La base científica de este experimento
The plant converts carbon dioxide from the air into oxygen and glucose by photosynthesis. Plants store glucose in long molecular chains called starch. Starch is synthesised and stored within chloroplasts and, in most species, is the primary storage form mobilised for translocation during the night.
Equipo utilizado
- Spirit burner — 5514.10
- Tripod stand — 5533.10
- Wire gauze — 5534.25
- Beaker 250 ml — 1118.35
- Beaker 500 ml — 1118.50
- Petri dish — 1253.00
- Tweezers — 8261.30
- Tin foil
- Small plant
Productos químicos y reactivos
- Lugol's solution — R:21-22 S:24/25
- Ethanol — R:11 S:7-16
- Water
Notas de seguridad
- Work in a fume cupboard or outdoors.
- Be careful handling the burner and hot glassware.
Preguntas para los alumnos
- Describe what happens to the leaf during each stage.
- Try to give an explanation.
Qué puedes esperar
<p>Dipping the leaf in boiling water kills cells and will allow the chemicals to mix. Treating the leaf with alcohol extracts chlorophyll and gives a clearer result.</p><p>Lugol’s solution is a specific iodine reagent that points out the presence of starch turning its colour to blue.</p><p>The leaf part exposed to light made carried out photosynthesis regularly, producing glucose that is stored as starch.</p>
Eliminación
Dispose of Lugol's solution into the acids and bases waste container.
Realiza este experimento en tu clase
Este experimento forma parte del « Mobile Lab » de ATP, un laboratorio autónomo que convierte un aula normal en un laboratorio de ciencias en pleno funcionamiento, con más de 200 experimentos de física, química, biología, robótica e ingeniería. « Gali », el tutor de IA integrado en ATP Connect, guía a los alumnos paso a paso y responde a sus preguntas en la mesa de trabajo.
Consulta el Mobile LabHabla con nuestro equipo