Essential Idea
The evolution of multicellular organisms allowed cell specialization and cell replacement.
Understandings
According to the cell theory, living organisms are composed of cells.
Organisms consisting of only one cell carry out all functions of life in that cell.
Surface area to volume ratio is important in the limitation of cell size.
Multicellular organisms have properties that emerge from the interaction of their cellular components.
Specialized tissues can develop by cell differentiation in multicellular organisms.
Differentiation involves the expression of some genes and not others in a cell's genome.
The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic development and also makes stem cells suitable for therapeutic uses.
Applications
Questioning the cell theory using atypical examples, including striated muscle, giant algae and aseptate fungal hyphae.
Investigation of functions of life in Paramecium and one named photosynthetic unicellular organism.
Use of stem cells to treat Stargardt's disease and one other named condition.
Ethics of the therapeutic use of stem cells from specially created embryos, from the umbilical cord blood of a new-born baby and from an adult's own tissues.
Skills
Use of a light microscope to investigate the structure of cells and tissues, with drawing of cells. Calculation of the magnification of drawings and the actual size of structures and ultrastructures shown in drawings or micrographs (VIDEO). (Practical 1)
Key Vocabulary
Cell
Cell theory
Unicellular
Multicellular
Surface area to volume ratio
Tissue
Differentiation
Gene
Genome
Stem cell
Stem cell therapy
Microscope
Magnification
Micrograph
Ultrastructure
Functions of life
Nutrition
Metabolism
Growth
Response
Excretion
Homeostasis
Reproduction
Scale
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 1.
Pages 4-12
Notes
A detailed set of notes, prepared by Bob Smullen, examining all of the IB learning expectations.
Essentially an online textbook outlining the entire subtopic in specific detail. Please use this resource.
A detailed set of notes created by Chris Paine examining all of the IB learning expectations.
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, prepared by Jacob Cedarbaum, examining U5 - U7 and A3 - A4, (slides 33-42) of the IB learning expectations.
1.1 Study Questions (NEW Syllabus)
A series of questions, prepared by Jacob Cedarbaum, to help check your understanding of the IB learning expectations. This is VERY GOOD practice. Answers (OLD).
Learning Activities
Created by the University of Utah, this interactive animation enables students to visualize the scale relevant to the microscopic world.
Created by McGraw-Hill, this interactive simulation enables students to enact changes in a cell's structure to determine how they will influence its surface area to volume ratio.
Virtual Lab - Virtual Microscope
This virtual lab, prepared by the University of Delaware, will help you better understand how to use a compound light microscope as well as how to calculate the size of a specimen. (Practical 1)
This activity will help students learn how to use a compound light microscope in order to view the ultrastructures of various cells as well as to make relevant calculations related to magnification and cell size. (Practical 1)
Microscope Magnification Activity
This reading and set of practice problems will help you understand the various calculations involved when viewing specimen using a microscope. (Practical 1)
Microscope Calculations Practice
Complete this worksheet to practice calculating total magnification, field of view (diameter) and size of a specimen.
More Microscope Calculations Practice
Complete this worksheet for additional practice with more challenging problems covering similar material to the previous worksheet.
Created by the University of Utah, this interactive presentation outlines what stem cells are and how they are related to the development of living organisms. Click HERE to see more stem cell resources from the University of Utah.
A short assignment designed to better understand Stargardt's Disease and one other condition.
This video describes the formulation of the cell theory as relevant discoveries were made due to advancements in microscope technology.
Must Watch Videos
This video outlines the reasons why a cell's surface area to volume ratio is important using a fantastically visible demonstration.
This video describes what stem cells are and how scientists are using them to treat illness.
This video outlines the affect of Stargardt Disease on the retina and describes how stem cells can be used to treat the disorder.
This video clarifies how we can determine the actual size of an object when viewing it through a microscope at varying magnifications. It's a little long but easy to understand.
Should Watch Videos
This video outlines the different types of stem cells that exist within the human body as well as how stem cell therapy can be used to treat illness.
This video outlines the evolution of multicellular organisms while examining some of the reasons why multicellular organisms have been successful.