General Biology 1: The Cell and the Microscope

A comprehensive deck covering cell theory, history, microscope components, organelle functions, and cell types.

Cell

The basic, fundamental unit of life and the smallest structural and functional unit of all living organisms.

Postulates of Cell Theory

1. All living organisms are made up of one or more cells. 2. A cell is the basic structural and functional unit of life. 3. All cells arise from pre-existing cells.

Unicellular Organisms

Organisms made of only one cell, such as Bacterium, Amoeba, and Paramecium.

Multicellular Organisms

Organisms made of many cells, such as Humans, Mango Trees, and Dogs.

Zacharias Janssen

The individual credited with inventing the 1st compound microscope in the 1580s.

Robert Hooke

A scientist who discovered cells in cork in 1665 and named them "cells" because they reminded him of monastery rooms.

Antonie Van Leeuwenhoek

Observed protozoa and bacterial cells in 1674, calling these tiny creatures "animalcules."

Theodor Schwann and Matthias Jakob Schleiden

Scientists who established the existing cell theory in the 1830s.

Eyepiece (Ocular lens)

The lens or combination of lenses closest to the eye in an optical instrument that allows you to view the specimen.

Objective Lens

Its main function is to gather incoming light, form a magnified image, and define the image's overall resolution and clarity.

Revolving Nosepiece

A component that allows a user to switch between different objectives using a rotatable turret assembly.

Fine Focus Knob

Used for precise, incremental adjustments to the distance between the stage and the objective lens to fine-tune the focus.

Coarse Focus Knob

Rapidly moves the microscope's stage or objective lens over large vertical distances to bring a specimen into rough view.

Illuminator (Light Source)

Provides the necessary illumination to brightly view a specimen by shining light up through the slide.

Diaphragm

Regulates the amount, angle, and intensity of light passing through a specimen.

Condenser

Its primary function is to gather, concentrate, and focus light from the illuminator into a precise cone on the specimen.

Stage

A supportive structure that securely holds and supports microscope slides containing the specimen.

Arm

Provides structural stability for observations and acts as a secure handle for safely carrying the microscope.

Base

Anchors the instrument, provides stability to prevent tipping, and houses the light source and electrical components.

Organelles

Refers to the "little organs" within the cell that perform specialized functions.

Nucleus

A membrane-enclosed organelle within a cell that contains the chromosomes.

Nucleolus

A spherical structure found in the cell's nucleus whose primary function is to produce and assemble the cell's ribosomes.

Cytoplasm

A gel-like structure where organelles are suspended; in eukaryotic cells, it is the content between the cell membrane and the nucleus.

Cell (Plasma) Membrane

Regulates what comes in and out of the cell and contains cholesterol to strengthen it and carbohydrates for cell recognition.

Cell Wall

A rigid structure that provides support, determines cell shape, and prevents bursting under osmotic pressure; present in plants, fungi, and prokaryotes.

Rough Endoplasmic Reticulum

Specializes in synthesizing, folding, and modifying proteins destined for the membrane, lysosomes, or secretion.

Smooth Endoplasmic Reticulum

Involved in lipid synthesis, carbohydrate metabolism, detoxification of drugs, and storage of calcium for muscle contraction.

Golgi Apparatus

Consists of flattened membrane-bound pouches known as cisternae; it tags, modifies, packages, and ships proteins and lipids.

Vesicles

Small, membrane-bound sacs within a cell that store and transport materials between locations or release them outside the cell.

Vacuoles

Store vital nutrients, water, and ions; in plant cells, they maintain shape through turgor pressure and sequester toxic waste.

Lysosomes

Membrane-bound organelles in animal cells that act as the garbage disposal by using digestive enzymes to break down worn-out cell parts and particles.

Peroxisomes

Responsible for oxidizing fatty acids and amino acids, and use the enzyme catalase to convert hydrogen peroxide into water and oxygen.

Mitochondria

The site of ATP synthesis featuring smooth outer and folded inner membranes (cristae); they contain DNA inherited exclusively from the mother.

Plastids

Double-membraned organelles in plants and algae responsible for manufacturing and storing food, pigments, and amino acids.

Chloroplast

The specific site of photosynthesis in plants, characterized by structures like granum and stroma.

Centrosome

The main microtubule-organizing center composed of a protein matrix and two barrel-shaped centrioles; helps build the mitotic spindle.

Cilia

Short, microscopic, hair-like appendages extending from the surface of a cell that use a back-and-forth beating motion.

Flagella

Long, microscopic, whip-like appendages primarily used by cells for movement via a propeller-like motion.

Cytoskeleton

A dynamic network of protein filaments (microfilaments, intermediate filaments, and microtubules) that provides structural scaffolding and a transit system.

Microvilli

Microscopic, finger-like cellular membrane protrusions that drastically increase a cell's surface area.

Prokaryotic Cells

Small ($0.1$ to $5.0\,\mu\text{m}$) and simple unicellular organisms with no nucleus, circular DNA, and reproduction via binary fission.

Eukaryotic Cells

Large ($10$ to $100\,\mu\text{m}$) and complex organisms with a nucleus, linear DNA, paired diploid ($2n$) chromosomes, and membrane-bound organelles.

Red Blood Cells

Specialized cells with a biconcave shape and no nucleus to increase surface area for carrying oxygen and carbon dioxide.

Nerve Cells (Neurons)

Specialized cells with long axons, branched dendrites, and a myelin sheath for transmitting electrical impulses over long distances.

Sperm Cell

Specialized cell with a long flagellum for swimming and an acrosome containing enzymes to penetrate the egg.

Binary Fission

A process of asexual reproduction where a single bacterial cell divides into two identical cells.