Exploring Onion Cell Structure and Behavior in Fresh and Salt Water

The video tutorial demonstrates an experiment using red onion cells to observe the effects of fresh and salt water under a microscope. The instructor explains how to select the correct onion layer, prepare a slide, and observe the cells. The experiment shows how salt water causes plasmolysis, shrinking the cells, and how fresh water can reverse this process through osmosis. The tutorial concludes with a summary of the observations and the scientific principles involved.

What is the first step in preparing the onion for the experiment?

• Peel off the inner layer without purple color

• Soak the onion in salt water

• Peel off the outer layer with purple color

• Cut the onion into small pieces

Why is it important to ensure the onion layer lays flat on the slide?

• To prevent the cover slip from breaking

• To ensure clear observation under the microscope

• To avoid contamination

• To make the onion layer more visible

What is the dark outer layer observed in the onion cells under the microscope?

• Nucleus

• Chloroplast

• Cell wall

• Cytoplasm

What is observed inside the cytoplasm of the onion cells?

• Vacuoles

• Chloroplasts

• Mitochondria

• Nuclei

What happens to the onion cells when salt water is applied?

• They change color

• They remain unchanged

• They expand

• They shrink

What is the term used to describe the shrinking of cells in salt water?

• Osmosis

• Plasmolysis

• Diffusion

• Hydrolysis

What is the role of the paper towel in the salt water application technique?

• To clean the slide

• To absorb excess water

• To draw salt water through the slide

• To hold the slide in place

How can the effects of plasmolysis be reversed in the onion cells?

• By adding fresh water

• By drying the slide

• By adding more salt water

• By applying heat

What process is demonstrated by the repeated shrinking and swelling of the onion cells?

• Diffusion

• Osmosis

• Active transport

• Filtration

What is the purpose of adding fresh water after salt water in the experiment?

• To reverse plasmolysis

• To clean the slide

• To observe color change

• To increase cell size