Cell Size & Microscopy Overview

These flashcards highlight key vocabulary and concepts related to cell size, microscopy, and the implications of surface area-to-volume relationships in biology.

Surface Area-to-Volume Ratio (SA:V)

A measure that represents the surface area a cell takes up (SA) compared to the amount of space inside of it (V), determining diffusion efficiency.

Microvilli (Cellular Strategy)

Finger-like projections on cells that increase surface area for more effective nutrient absorption without the cell having to increase its volume

Zygote

The first cell formed when a sperm fertilizes an egg, which eventually develops into an organism.

Microscope

An instrument used to see objects that are too small to be seen by the naked eye, significant for the discovery of cells.

Compound Microscope

A microscope that uses multiple lenses to magnify an image, invented by Zacharias Janssen.

Animalcules

The term coined by Anton van Leeuwenhoek for the tiny living organisms he observed under his microscope.

Cell Size

Most cells are between 10-30 micrometers (µm) in diameter and often require a microscope to be seen

Small Cell Size

The smaller the size of a cell, the higher the SA:V Ratio

Large Cell Size

The larger the cells are, the lower the SA:V Ratio

Risks nutrient shortage and waste accumulation

Multicellular Tissues

As size increases, surface area doesn’t keep up with the volume

They generally have a low SA:V ratio if they rely on their outer surface

They are able to compensate for this through cellular strategies

Ostrich Egg (Cell Size)

15 cm in diameter (Gigantic)

Frog Egg (Cell Size)

1-2 mm in diameter (Huge)

1000 ųm

Human Cell (Cell Size)

10-30 ųm (micrometers) in diameter (Normal Size)

Red Blood Cell (Cell Size)

10 ųm (micrometers) in diameter (Normal)

Lactobacillus Bacteria (Cell Size)

1-2 ųm (micrometers) in diameter (Small)

Multicellularity (Cell Strategy)

The condition of being composed of many cells, which allows for shared surface area and greater metabolic efficiency.

Robert Hooke (1635 - 1703)

Published 'Micrographia' in 1665

Came up with the term 'cell' after observing cork (dead plant tissue) under a microscope

Anton van Leeuwenhoek (1632-1723)

Dutch craftsman who built exceptional single-lens microscopes

First to observe “animalcules” (microscopic living organisms) in pond water (1674)

Discovered bacteria in dental plaque (1683)

Discovered detailed sperm morphology (1677-78)

Zacharias Janssen (16th Century)

Invented the first compound microscope that included multiple lenses. It was handheld.

It can magnify images from 3-10x

Cell Membrane (In relation to SA:V)

Responsible for cell diffusion and is the surface area (SA) of the cell

The gateway to “resources in” and “wastes out”

Cytoplasm (In relation to SA:V)

Where metabolic processes occur

The volume (V) of the cell

Diffusion

The process by which molecules spread from areas of high concentration to areas of low concentration, limited by SA:V in larger cells.

Compound Light Microscope

Uses light to view stained living cells, and basic structures.

It is the weakest of the three microscopes

Scanning Electron Microscope (SEM)

Produces 3-D images of surfaces and is excellent for surface detail

The mid microscope of the three

Transmission Electron Microscope (TEM)

Uses electrons transmitted through ultra thin samples to see internal structures in extreme detail

The strongest microscope of the three