Unit 3: Cell Biology and Microscopy Study Guide

Vocabulary practice flashcards covering microscope components, magnification calculations, tenets and scientists of cell theory, prokaryotic vs. eukaryotic structures, plant vs. animal cell differences, and organelle functions from Unit 3.

Eyepiece

The optical lens component of a microscope that typically provides a magnification power of $10\times$.

Scanning Power Objective Lens

The microscope objective lens with a magnification power of $4\times$; it is the best objective to start with when focusing a specimen.

Low Power Objective Lens

The objective lens on a light microscope with a magnification power of $10\times$.

High Power Objective Lens

The objective lens on a light microscope with a magnification power of $40\times$.

Total Magnification

The overall magnification achieved by multiplying the eyepiece magnification by the objective lens magnification (for example, under high power: $10\times \times 40\times = 400\times$).

Coarse Focus

The adjustment knob used for broad focusing that should NOT be adjusted when viewing a specimen under the high power objective.

Robert Hooke

The historical scientist recognized as the first to discover cells.

Matthias Schleiden

The scientist who contributed to the cell theory by concluding that all plants are made of cells.

Theodor Schwann

The scientist who contributed to the cell theory by concluding that all animals are made of cells.

Rudolf Virchow

The scientist who contributed to the cell theory by stating that all cells come from other cells.

Cell Theory

A fundamental biological theory stating that all living things are made of cells, cells are the basic units of life, and all cells come from other cells.

Universal Cell Structures

The four structural components shared by all cells (both prokaryotic and eukaryotic): cell membrane, DNA, cytoplasm, and ribosomes.

Prokaryotic Cells

Small, simple cells, such as bacteria, that lack a nucleus, lack large membrane-bound organelles, and possess circular DNA.

Eukaryotic Cells

Large, complex cells, such as plant and animal cells, that contain a membrane-bound nucleus, large organelles, and linear DNA.

Unicellular Organism

An organism composed of one single cell.

Multicellular Organism

An organism made of many cells organized into specialized tissues, organs, and organ systems.

Organelle

A specialized, membrane-bound subunit within a cell that divides cellular labor to keep the cell alive and functioning.

Plasmid

Small rings of bacterial DNA separate from the chromosome that carry genetic information for resistance to antibiotics.

Pilus

Extensions of the bacterial plasma membrane that help bacteria stick to many different types of surfaces.

Capsule

An external protective layer that provides enhancement for some bacteria, enabling them to cause diseases.

Bacterial Chromosome

A single circular DNA molecule that contains the majority of a bacterium's genes and is not enclosed within a nucleus.

Ribosome

The protein factory of the cell responsible for building proteins; supports immune defense and cell structure.

Smooth Endoplasmic Reticulum (Smooth ER)

The organelle responsible for synthesizing membrane lipids and helping detoxify the cell.

Rough Endoplasmic Reticulum (Rough ER)

An organelle dotted with ribosomes that serves as a site of protein synthesis.

Chloroplast

Plant organelles that convert light energy from the sun into chemical energy through photosynthesis.

Cell Membrane

A semipermeable barrier surrounding the cell that separates the internal environment from the outside and regulates what enters and exits.

Cell Wall

An external support structure found outside the cell membrane in plants and bacteria that provides rigid shape and protection against osmotic pressure.

Lysosomes

Organelles containing digestive enzymes that break down food, waste, and foreign materials.

Nucleolus

A specialized dense structure located inside the nucleus that makes ribosomes.

Centrioles

Organelles found in animal cells that assist with cell division.

Vacuole

The storage center of a cell; exists as a large central structure in plant cells and as smaller units in animal cells.

Cytoplasm

The liquid fluid part of the cell surrounding the DNA and organelles that gives the cell its shape and supports the organelles.

Golgi Apparatus

The cellular organelle that sorts, modifies, and packages proteins for transport.

Nuclear Envelope

The double membrane surrounding the nucleus that regulates what enters and exits the nuclear compartment.

Mitochondria

The energy powerhouse of the cell responsible for generating cellular energy.

Vesicles

Small membrane-bound sacs that help move substances within the cell.

Nucleus

The central control organelle that regulates all cell activity and houses the cell's genetic material (DNA).

Cytoskeleton

An internal framework of fibers that gives cells their shape and helps anchor organelles in place.

Cilia

Short, numerous membrane-bound surface projections that assist with movement; not classified as organelles.

Flagellum

A long, whip-like membrane-bound extension present in fewer numbers that supports cellular mobility; not classified as an organelle.