Cell Biology and Microscopy

Vocabulary practice flashcards covering cell theory, microscopy techniques, organelle ultrastructure, plant vs. animal cell comparisons, and cellular investigation procedures.

Cell Theory

The biological principle stating that all living things are composed of one or more cells, the cell is the most basic unit of life, and all cells arise only from pre-existing cells.

Cell Continuity

The ability of cells to divide and survive continuously from one generation to the next, establishing that all cells arise only from pre-existing cells.

Unicellular Organism

An organism consisting of a single cell that carries out all biological activities, characterized by small size and a short length of life.

Multicellular Organism

An organism composed of many cells in which different groups of cells carry out different functions (e.g., muscle cells contracting to allow movement), characterized by large size and a long length of life.

Cell Microstructure

The detail and internal structure of cells as viewed under a light microscope.

Cell Ultrastructure

The fine detail of cells or cell structures as seen using an electron microscope.

Scanning Electron Microscope (SEM)

A type of electron microscope that projects a beam of electrons onto the surface of an object to reveal surface detail.

Transmission Electron Microscope (TEM)

A type of electron microscope that projects a beam of electrons through a very thin section of a sample to show internal structures.

Total Magnification

The overall magnification of a light microscope, calculated as: $\text{Total magnification} = \text{objective lens power} \times \text{eyepiece lens power}$

Diaphragm (Microscope)

The sub-stage component of a light microscope that adjusts the amount of light reaching the specimen slide.

Condenser (Microscope)

An optical component that focuses light onto the microscope slide (not present in all light microscopes).

Protoplasm

All the living matter in a cell, enclosed by the cell membrane and comprising both the cytoplasm and the nucleus.

Cytoplasm

The living material in a cell located outside the nucleus, composed of suspended organelles and cytosol.

Cytosol

The liquid ground substance surrounding the organelles within the cytoplasm.

Cell Wall

A rigid, fully permeable outer layer in plant cells made from the structural carbohydrate cellulose that supports and strengthens the cell.

Vacuole

A membrane-bound organelle prominent in plant cells that provides cellular strength by pushing cytoplasm against the cell wall (turgor pressure) and stores cell sap containing salts and sugars.

Phospholipid Bilayer

A double layer of phospholipids forming the basis of biological membranes, consisting of water-loving (hydrophilic) phosphate heads and water-hating (hydrophobic) lipid tails.

Nuclear Pores

Tiny openings in the double nuclear membrane that make it selectively permeable by allowing molecules to move into and out of the nucleus.

Mitochondrion

An oval-shaped, double-membrane organelle that acts as the site of cellular respiration to supply energy; contains non-nuclear loop DNA (mtDNA) and an infolded inner membrane to maximize surface area for energy production.

Ribosome

A tiny cytoplasmic organelle made of ribosomal RNA (rRNA) and protein that functions in protein synthesis, including the production of enzymes.

Chloroplast

A plant organelle surrounded by a double membrane containing the green pigment chlorophyll and a loop of non-nuclear DNA (cpDNA); serves as the site of photosynthesis (an anabolic reaction).

Smooth Endoplasmic Reticulum (SER)

A system of membrane tubules lacking ribosomes that synthesizes lipids, stores calcium in liver cells, and neutralizes or breaks down poisons in liver cells.

Rough Endoplasmic Reticulum (RER)

A system of membrane tubules studded with ribosomes on its outer surface that produces and transports proteins and new membranes.

Golgi Apparatus

An organelle made of flattened membrane sacks that modifies, sorts, and packages proteins and lipids into vesicles for transport to target cellular destinations.

Prokaryotic Cell

A small, single-celled organism (such as bacteria from kingdom Monera) that lacks a nucleus and membrane-enclosed organelles, containing a single circular loop of DNA.

Eukaryotic Cell

A complex cell type containing a true nucleus enclosed by a double nuclear membrane and membrane-enclosed organelles such as mitochondria and chloroplasts (found in animals, plants, fungi, and protists).

Methylene Blue

A biological stain used when examining animal cells (such as human cheek cells) that stains the nucleus a deep blue and the cytoplasm light blue.

Iodine Solution

A chemical stain used in light microscopy of plant cells (such as onion epidermis) that stains the nucleus orange and the cytoplasm yellow.

Cover Slip

A thin, transparent square of glass placed at an angle over a microscopic specimen to eliminate air bubbles, protect the objective lens from stain, and keep cells from drying out.