Microscope Parts + Cell Structure/Function

Base

Supports the microscope; holds the light

Stage

Table of the microscope where the slide/specimen is placed.

Arm

Basic frame to which the base, body, and stage are attached.

Diaphragm

Wheel-shaped device attached to the stage, which regulates the amount of light passing through the specimen.

Objectives

The parts that magnify the specimen and form an image

Eyepiece/Ocular

The upper optical component you look through, which further magnifies the image and brings light rays into focus.

Coarse focus

Large knob that moves the stage up and down quickly to focus the image. This knob must never be used when the high power objective is in use!

Fine focus

Small knob that moves the stage up and down slowly to focus the image more precisely. When on high power, use only this knob!

Stage clips

Holds the slide in place.

Total magnification

Eyepiece * Objective

Measuring size of microscopic object

1. Determine diameter of the field of view

2. Estimate number of objects that could fit across the diameter

3. Diameter of field/number of objects = size of object

Cell stains

Light microscopes are limited in detail, and most cells are transparent, which is why chemical stains or dyes are necessary to make cells visible.

Cell theory

1. All living things are made up of cells

2. Cells are basic units of structure & function in living things

3. New cells are produced from existing cells

Prokaryote

Organisms that contain prokaryotic cells, which are cells that don’t contain a nucleus or membrane-bound organelles. 

Bacteria

Large group of uniceullular prokaryotes.

Archaea

Very similar to bacteria, except cell wall lacks a certain compound, membrane is made up of different lipids, and the DNA sequence is different.

Eukaryotic cell types

Plants, animals, protists, fungi

Protists

Any eukaryotic organism that is not a plant, animal, or fungus. They display a far greater degree of diversity than any other eukaryote.

Plant cell

A type of eukaryotic cell that is the basic unit of life in plants, characterized by a cell wall, chloroplasts, and a central vacuole.

Animal cell

A type of eukaryotic cell that is the basic unit of life in animals. Some organelles that only animal cells contiain are lysosomes and centrioles.

Fungi

A eukaryote such as mushrooms, mold, and yeast. Unlike plants, fungi don’t photosynthesize, and instead feed on organic matter.

Cell membrane

Thin, flexible barrier that surrounds all cells and separates one cell from another cell. It regulates the passage of materials into and out of the cell.

Lipid bilayer

Gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings. Made up of phospholipids, which have a water-loving head and a water-fearing tail'; the heads will always face the cytoplasm and extracellular matrix.

Selectively permeable

Some substances can pass through and some can’t. Most biological membranes are like this.

Mitochondria

Converts energy from nutrients into ATP (adenosine triphosphate) through cellular respiration, a process that releases energy by breaking down glucose and other food molecules into simpler substances.

Lysosomes

Contains digestive enzymes that break down old organelles, food particles, and pathogens. Only in animal cells.

Nucleus

Stores and protects the cell’s genetic material and directs all cellular activities such as growth, metabolism, and reproduction.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids for transport inside or outside the cell.

Vesicles

Small, spherical sacs that are classified acording to their contents.

Ribosomes

Assembles amino acids into proteins using instructions from mRNA (translation).

Cell wall

Rigid structure that provides strength, support, and protection to a plant cell.

Centriole

Two short cylinders found near the nucleus which help to organize microtubules during cell division. Only found in animal cells.

Endoplasmic reticulum

A network of membranes that produces, folds, and transports proteins and lipids.

Smooth endoplasmic reticulum

Doesn’t have ribosomes attached. Synthesizes lipids and steroids, metabolizes carbohydrates, detoxifies, and maintains calcium homeostasis.

Rough endoplasmic reticulum

Has ribosomes attached. Newly assembled proteins leave the ribosome and are inserted into spaces in the rough ER where they are modified and shaped into functioning proteins.

Chloroplast

Converts light energy into chemical energy (glucose) through photosynthesis. Gives plants give their green color.

Cytoskeleton

Provides shape, organization, and movement to the cell. Made up of microfilaments (one is thread-like actin structure) and microtubules (another protein filament that is hollow and tube-shaped).

Turgor pressure

Pressure that water molecules exert against the cell wall ; this allows the plant to support heavy structures such as leaves and flowers.

Vacuole

Stores water, nutrients, and waste. Animal cells have multiple smaller ones while plant cells have one large vacuole which exerts turgor pressure to help maintain shape.

Mitosis

Cell division that results in two daughter cells with the same number of chromosomes as the parent nucleus. Asexual reproduction.

Meiosis

Cell division that results in four daughter cells with half the number of chromosomes as the parent cell. Sexual reproduction.