1.2: Ultrastructure of cells
Teaching time: 3 hours          Practical time: 0 hours
Key vocabulary
Prior learning & retrieval practice
Review the functions of life in a paramecium
Review topic 1.1 introduction to cells
Eukaryotes
U2: Eukaryotes have a compartmentalised cell structure.
S2: Drawing of the ultrastructure of eukaryotic cells based on electron micrographs.
Exercise 1: Study the Quizlet decks below
A1: Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf.
Exercise 2: Describe functions of each of the organelles found in eukaryotes. State whether you would find it in a pancreatic exocrine cell or a pallisade cell or both.
Prokaryotes
U1: Prokaryotes have a simple cell structure without compartmentalisation.
S1: Drawing of the ultrastructure of prokaryotic cells based on electron micrographs.
Exercise 3: Study the Quizlet deck below Guidance from the syllabus: Drawings of prokaryotic cells should show the cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA.
Exercise 4: Describe functions of each of the organelles found in prokaryotes. State whether you would find it in a pancreatic exocrine cell or a pallisade cell or both. Use the table provided.
A2: Prokaryotes divide by binary fission.
Exercise 5: What is binary fission? Connect-Extend-Challenge from your textbook.
Electron Microscopes
Nature of science: Developments in scientific research follow improvements in apparatus—the invention of electron microscopes led to greater understanding of cell structure. (1.8)
U3: Electron microscopes have a much higher resolution than light microscopes.
Exercise 6: Use the weblink to answer these questions:
What is the maximum magnification of a light microscope and an electron microscope?
What structures can be seen with an electron microscope that can't be seen with a light microscope?
When was the electron microscope invented?
S3: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
Exercise 7: For each of these images try to identify the organelles and deduce the function of the cell.
Prokaryotes vs Eukaryotes
Essential idea: Eukaryotes have a much more complex cell structure than prokaryotes.
Exercise 8: Compare and contrast Prokaryotic and Eukaryotic cells.
(The command term compare and contrast refers to similarities and differences. When answering this kind of question you must refer to both of the items that you are comparing in the same sentences.)
Good words to use when comparing something in your IB exams are: both, while, whereas, and. You can also answer this type of question with a table.
Example:
1. Prokaryotes have 70S ribosomes while Eukaryotes have 80S ribosomes.
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