3.1 - Cell Biology

What did Robert Hooke and Anton van Leeuwenhoek do for the history of cells?

• Robert Hooke used an early microscope to observe slices of cork. He saw “little boxes” that reminded him of the cells that monks live in, coining the name cells

• Anton van Leeuwenhoek was the first to observe living cells, including

  • algae Spirogyra

  • Vorticella

    • He dubbed these microorganisms animalcules

What is cell theory and its rules?

Cell theory is the summary of work from various scientists and is comprised of 3 rules:

1. Every organism is made up of 1+ cells

2. Cells are the most basic unit of structure in an object

3. New cells are only formed from the self-reproduction of past cells

How did microscopy affect the study of cell biology?

The study of cell biology was limited until the invention of the compound light microscope, which eventually led to the 7 characteristics of life:

7 Characteristics of Life

1. Living things are made up of organized parts

2. Living things need energy from their surroundings

3. Living things perform chemical reactions

4. Living things change with time

5. Living things respond to their environment

6. Living things can reproduce

7. Living things maintain homeostasis

How do cells vary, and why?

• Cells are very diverse:

  • shape

  • size

  • organization

  • function

This diversity has led to different functions, either simple or complex. These structures have evolved for maximum effectiveness in function

How does the volume of cells relate to the surface area and why?

Bigger cell → lower surface area: volume ratio

Cells usually have more surface area despite the ratio however in order to expel more waste and to allow entrance of nutrients

Name the basic parts of the cell.

• Plasma Membrane

• Cytoplasm

• Control Center

What is the Plasma Membrane and its purpose?

It covers the surface of the cell like a wall for the entrance and exit of materials

What is the Cytoplasm and its purpose?

It is the region of the cell inside the membrane and contains important parts:

• Fluids

• Cytoskeleton

• All organelles (except nucleus)

• The cytosol

What is the Control Center (nucleus) and its purpose?

It is the largest controls the majority of functions in the cell. It maintains its shape with a protein skeleton called a nuclear matrix

What are the two types of organisms and their differences

Prokaryotes and Eukaryotes

• Prokaryotes have prokaryotic cells

• Eukaryotes have eukaryotic cells

Characteristics of Prokaryotic Cells

• Lacks a membrane bound nucleus and organelles

• Divided into two domains:

  • Bacteria: related to basic cell life forms

  • Archaea: Related to eukaryotic cells

Characteristics of Eukaryotic Cells

• Has a membrane bound nucleus and organelles

• Larger cells than prokaryotes

Difference between a Colonial Organism and a Multicellularity

• Colonial organisms are organisms with cells that live together in a connected group.

• Multicellularity is an organism that has cells that cannot survive without each other.

Colonial Organisms can live independently, but a multicellularity has dependent cells