Intro to cells

Principles of cell theory

-All living things are made of cells

-Cells are the smallest unit of life

-Cells can only come from preexisting cells

All living things carry out 7 basic functions integral to survival:

metabolism, growth, reproduction, responsiveness, homeostasis, excretion, and nutrition.

The rate of metabolism of a cell is a function of its

mass / volume  (larger cells need more energy to sustain essential functions)

The rate of material exchange is a function of its

surface area (large membrane surface equates to more material movement)

Larger SA:Vol ratio

is essential for efficient material exchange, enabling cells to thrive.

Small SA: Vol ratio

limits material exchange efficiency, causing possible cell dysfunction, help water retention and heat loss, and reduced metabolic activity.

To calculate the linear magnification of a drawing or image, the following equation should be used

• Magnification = Image size (with ruler) ÷ Actual size (according to scale bar)

To calculate the actual size of a magnified specimen, the equation is simply rearranged:

• Actual Size = Image size (with ruler) ÷ Magnification