Introduction to cilia, flagella and pseudopodia | Cells | High school biology | Khan Academy

TL;DR

Unicellular organisms have complex structures such as pseudopods, cilia, and flagella, which allow them to move and carry out various functions.

Transcript

• [Instructor] The goal of this video is to appreciate some of the structures that you see even in unicellular organisms. So this right over here is a picture of the amoeba Chaos carolinense. And what you see here is a projection coming off from the main part of the cell, and this is called a pseudopod, which is referring to it being a false foot. ... Read More

Key Insights

• ❓ Unicellular organisms have complex structures that facilitate movement and other functions.
• 🥖 Cells are not simply fluid-filled bags but intricate structures still being studied by biologists.
• ❓ Unicellular organisms can have unique characteristics like multiple nuclei and highly fragmented DNA.

Questions & Answers

Q: What are pseudopods and how do amoebas use them?

Pseudopods are projections that resemble false feet, allowing amoebas to move and engulf prey. These structures rely on microstructures that extend or contract to facilitate movement.

Q: How do cilia help organisms like Oxytricha trifallax move?

Cilia are hair-like projections that move in unison, allowing Oxytricha trifallax to move or move particles. For example, cilia found in the lining of lungs help move saliva and particles up or down.

Q: What is unique about Oxytricha trifallax as a eukaryote?

Oxytricha trifallax can have two nuclei and highly fragmented DNA with thousands of chromosomes. During mating, it merges with another Oxytricha trifallax, resulting in an exchange of genetic material.

Q: How do flagella function in organisms like Chlamydomonas?

Flagella in organisms like Chlamydomonas function as a single, whip-like tail for movement. The flagellum is extremely thin and can be rotated by the cell to enable movement.

Summary & Key Takeaways

• Unicellular organisms like amoebas use pseudopods, false feet, to move and attack other organisms.

• Cilia, hair-like structures, are used by organisms like Oxytricha trifallax to move or move other particles.

• Some unicellular organisms have a single flagellum, a tail-like structure, for movement.