Eukaryotic cells are distinguished by their internal organization, especially their nucleus and membrane-bound organelles. This lesson introduces their major characteristics, the diversity of their shapes, and the organization of their genetic material.
Eukaryotes include protozoans, algae, fungi, plants, and animals. Some are single-celled organisms, while others consist of many specialized cells. Their cells are generally larger than prokaryotic cells: eukaryotic cells are commonly about 5–20 μm, compared with roughly 0.5–1 μm for many prokaryotes.
All flashcards
How does cell shape relate to cell function?
Cell shape reflects factors such as function, cytoskeletal organization, cytoplasm viscosity, boundary rigidity, and surrounding pressure.
What evidence supports the endosymbiotic origin of mitochondria?
Mitochondria have their own DNA and 70S ribosomes, bacterial-like features, and two surrounding membranes.
What is the role of lysosomes?
Lysosomes contain digestive enzymes that break down particles, damaged organelles, and cellular debris within a membrane-bound compartment.
How do microfilaments support cell activities?
Actin microfilaments contribute to cell-shape changes, movement, muscle contraction, cytoplasmic streaming, and cytokinesis.
What do rough and smooth ER mainly do?
Rough ER makes proteins for membranes or export; smooth ER contributes to lipid synthesis, carbohydrate metabolism, and detoxification.
Quiz questions
Which outcome is typical of meiosis?Answer: Two nuclear divisions produce four genetically distinct haploid cells.
Which ribosomes are generally found in the eukaryotic cytoplasm and on rough ER?Answer: 80S ribosomes
Which organelle receives vesicles at its cis face and modifies and sorts their contents?Answer: Golgi apparatus
Which cytoskeletal fibers are made of two intertwined strands of actin?Answer: Microfilaments
How do eukaryotic flagella typically generate bending movement?Answer: Dynein causes adjacent microtubules to slide relative to one another.
Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.