Microscope and Cytology Study Guide

Vocabulary flashcards covering microscope components, phospholipid bilayer structures, cell organelles, membrane transport mechanisms, tonicity, and the phases of the cell cycle.

Microscope

An optical instrument used for viewing magnified images of small objects.

Eyepiece

The component of a microscope that holds the ocular lens.

Ocular Lenses

Lenses located at the top of the microscope that provide $10\times$ magnification.

Nosepiece

The revolving part of the microscope that holds and rotates the objective lenses.

Objective Lenses

Lenses with different power magnifications ranging from $4\times$ to $100\times$.

Stage

The flat platform on a microscope where the slide sits.

Stage Clips

Clips on the stage that hold the slide securely in place.

Mechanical Stage Adjustment Knobs

Knobs used to adjust the stage up/down and left/right.

Low Power Objective Lens

A $4\times$ magnification lens, also called a scanning lens, color-coded red.

Medium Power Objective Lens

A $10\times$ magnification objective lens, color-coded yellow.

High Power Objective Lens

A $40\times$ magnification objective lens, color-coded blue.

Oil Immersion Objective Lens

A $100\times$ magnification lens color-coded black, used exclusively with oil to refract light into the specimen.

Iris Diaphragm

A device on the microscope that allows control of how much light passes through the slide.

Lamp

The light source for the microscope.

Coarse Adjustment Knob

A knob that moves the stage up and down to adjust the gross focus of the slide.

Fine Adjustment Knob

A knob that moves the stage up and down slightly to allow fine-tuning of the focus of the slide.

Depth of Field

The vertical thickness of a specimen that is in clear focus; as magnification increases, depth of field decreases.

Phospholipid Bilayer

A double layer of phospholipids forming the structural framework of the plasma membrane.

Phosphate Head

The polar, hydrophilic portion of a phospholipid that faces the intracellular and extracellular portions of the cell.

Fatty-Acid Tails

The nonpolar, hydrophobic portion of a phospholipid that forms the inside of the bilayer, repelling molecules from easily diffusing through.

Integral Proteins

Proteins embedded directly into the plasma membrane, acting as channel proteins, enzymes, or transport proteins.

Peripheral Proteins

Proteins attached to the intracellular or extracellular face of the membrane, functioning as structural proteins or enzymes.

Glycolipid

A lipid molecule with attached sugars located on the cell membrane.

Glycoprotein

A membrane protein with attached sugars.

Cholesterol

A lipid component that regulates the fluidity of the plasma membrane.

Cytoplasm

The contents of the cell consisting of the cytosol plus organelles.

Nuclear Envelope

The double-layered plasma membrane surrounding the nucleus.

Nuclear Pores

Openings in the nuclear envelope that allow transport of materials into and out of the nucleus.

Nucleolus

Regions within the nucleus where RNA and ribosomes are created.

Chromatin

Uncondensed DNA contained within the nucleus.

Cytoskeleton

An internal structural network composed of microfilaments (actin), intermediate filaments, and microtubules.

Microvilli

Finger-like extensions of the plasma membrane that increase the surface area of the cell.

Cilia

Hair-like extensions of the plasma membrane that propel material across the surface of the cell.

Flagella

Extensions of the plasma membrane that provide cell motility, found in humans only on sperm cells.

Ribosomes

Cellular structures responsible for creating proteins.

Smooth Endoplasmic Reticulum

Organelle responsible for lipid and cholesterol synthesis, as well as detoxifying the cell of drugs and toxins.

Rough Endoplasmic Reticulum

Organelle studded with ribosomes that modifies proteins made by the ribosomes.

Golgi Apparatus

Organelle that packages and modifies proteins for export or for use inside the cell.

Mitochondria

Organelles serving as the primary site of ATP synthesis within the cell.

Vesicles

Small membrane-bound vehicles created from a portion of plasma membrane that has budded off.

Peroxisome

A vesicle containing specialized enzymes (such as peroxidase) to detoxify chemicals.

Lysosome

A vesicle containing digestive enzymes to digest cellular material.

Centrosome

The microtubule organizing center of the cell, composed of two centrioles, which creates and destroys microtubules.

Diffusion

The movement of solute particles down a concentration gradient from an area of high concentration to low concentration.

Osmosis

The net movement of water from an area of low solute concentration across a selectively permeable membrane toward a high solute concentration.

Tonicity

The relative concentration of solutes dissolved in solution which determines the direction and extent of diffusion of water across a membrane.

Isotonic Solution

A solution in which the solute concentration inside and outside the cell are approximately equal, resulting in balanced water movement.

Hypotonic Solution

A solution with a lower solute concentration than the inside of the cell, causing net water entry into the cell and potential apoptosis through lysis.

Hypertonic Solution

A solution with a higher solute concentration than the inside of the cell, causing water to leave the cell at a higher rate and the cell to shrink (crenulation).

Cell Cycle

The ordered series of events involving cell growth and cell division, comprised of Interphase and M Phase.

Interphase

The longest phase of the cell cycle where the cell carries out normal functions, grows, and prepares for cell division.

G1 Phase

The first growth phase of interphase where the cell grows larger and replicates organelles.

S Phase

The synthesis phase of interphase where DNA replication occurs, producing sister chromatids.

G2 Phase

The second growth phase of interphase where the cell continues growing, replicating organelles, and preparing for mitosis.

Prophase

First stage of mitosis where chromatin condenses into chromosomes, the nuclear membrane deteriorates, and centrioles form the mitotic spindle.

Metaphase

Stage of mitosis where centrioles are fully polar and chromosomes line up along the metaphase plate at the center of the cell.

Anaphase

Stage of mitosis where sister chromatids are pulled apart to opposite poles of the cell by the mitotic spindle.

Telophase

Final stage of mitosis where nuclear membranes reform, chromosomes decondense into chromatin, the mitotic spindle deteriorates, and a cleavage furrow forms.

Cytokinesis

The division of the cytoplasm, during which the plasma membrane separates to form two distinct daughter cells.