Lesson 3 and 4 - Microscope
Lesson Objectives
Content Objective: Use a microscope to identify parts of a cell and to calculate the size and magnification of cells and use this information to create scientific drawings of cells. To observe the characteristics of life in unicellular organisms.
Language Objective: Create a labeled diagram of eukaryotic cells with correct labels, titles and scale bars and determine the size of organism from drawings and pictures taken from microscopes.
Syllabus Details:
A2.2.2 - microscopy skills & calculating magnification - Students should have experience of making temporary mounts of cells and tissues, staining, measuring sizes using an eyepiece graticule, focusing with coarse and fine adjustments, calculating actual size and magnification, producing a scale bar and taking photographs.
A2.2.10 - Cell types and cell structures viewed in light and electron micrographs - Students should be able to identify cells in light or electron micrographs as prokaryote, plant or animal. In electron micrographs, students should be able to identify these structures: nucleoid region, prokaryotic cell wall, nucleus, mitochondrion, chloroplast, sap vacuole, Golgi apparatus, rough and smooth endoplasmic reticulum, chromosomes, ribosomes, cell wall, plasma membrane and microvilli.
A2.2.11 - Drawing and annotation based on electron micrographs - Students should be able to draw and annotate diagrams of organelles (nucleus, mitochondria, chloroplasts, sap vacuole, Golgi apparatus, rough and smooth endoplasmic reticulum and chromosomes) as well as other cell structures (cell wall, plasma membrane, secretory vesicles and microvilli) shown in electron micrographs. Students are required to include the functions in their annotations.
A2.2.9 - Atypical cell structure in eukaryotes "Use numbers of nuclei to illustrate one type of atypical cell structure in aseptate fungal hyphae, skeletal muscle, red blood cells and phloem sieve tube elements"
A2.2.3 - developments in microscopy - Include the advantages of electron microscopy, freeze fracture, cryogenic electron microscopy, and the use of fluorescent stains and immunofluorescence in light microscopy.
Activity 1: Cell Theory Discovery
Watch this video, BBC - The Cell, from 32 min to 50 min. It discusses the discovery of cells and cell theory. The basics of this theory are here:
1. all known living things are made up of cells.
2. the cell is a structural & functional unit of all living things.
3. all cells come from pre-existing cells by division
Activity 2: Using Microscopes
Activity 3 - Atypical Cell Structures in Eukaryotes
Instructions:
Preparation
Think
Individually Read and take notes on atypical cell structures in eukaryotes focusing on aseptate fungal hyphae, skeletal muscle cells, red blood cells, and phloem sieve tube elements. Please focus on the number of nuclei in these cells and how it contributes to their atypical structure. Write down your observations, thoughts, and any questions you have.
Pair
Form pairs with a classmate. Discuss your individual findings for another 10 minutes adding to your notes.
Share your understanding of the atypical structure of each cell type and how the number of nuclei relates to it.
Discuss the similarities and differences in the cell structure, especially the nuclei.
Discuss why these cells are considered atypical and how their structure supports their function.
Share any questions or uncertainties you had during the individual thinking phase.
Share
With the larger class group, each pair will share their findings
Reflection
Discuss atypical examples in eukaryotic cells. (4)