General Biology 1: The Cell and the Microscope

Flashcards covering historical figures in biology, microscope parts and their specific functions, cellular organelles, distinctions between prokaryotic and eukaryotic cells, and specialized cell modifications.

Cell

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

Microscope

A laboratory instrument used to examine objects that are too small to be seen with the naked eye.

Postulate 1 of Cell Theory

All living organisms are made up of one cell or more cells.

Postulate 2 of Cell Theory

A cell is the basic structural and functional unit of life.

Postulate 3 of Cell Theory

All cells arise from pre-existing cells.

Zacharias Janssen

The individual who invented the 1st compound microscope in the 1580s.

Robert Hooke

Discovered cells in a cork in 1665 and named them "cells" because they reminded him of a monastery.

Antonie Van Leewenhoek

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 that allows the user to view the specimen.

Revolving Nosepiece

A component of a light microscope which allows a user to switch between different objectives using a rotatable turret assembly.

Coarse Focus

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

Fine Focus

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

Diaphragm

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

Condenser

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

Illuminator

Provides the necessary illumination to brightly view a specimen.

Arm

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

Base

Anchors the entire instrument, provides stability to prevent tipping, and serves as the housing for the light source and electrical wiring.

Objective lens

The lens closest to the subject that gathers light and forms a primary, magnified image with defined resolution and clarity.

Nucleus

A membrane-enclosed organelle within a cell that contains the chromosomes and allows selective passage of molecules through nuclear pores.

Nucleolus

A spherical structure in the nucleus responsible for producing and assembling ribosomes and transcribing ribosomal RNA genes.

Cytoplasm

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

Cell (Plasma) Membrane

Regulates what comes in and out of the cell; contains cholesterol for strength 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, algae, and prokaryotes.

Rough Endoplasmic Reticulum

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

Smooth Endoplasmic Reticulum

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

Golgi Apparatus

A series of flattened cisternae that tags, ships, and performs post-translational modifications like glycosylation and phosphorylation on proteins and lipids.

Vesicles

Small, membrane-bound sacs that store and transport materials, including transport vesicles and secretory vesicles.

Vacuoles

Organelles that store nutrients, water, and ions; maintaining turgor pressure in plant cells and sequestering toxic byproducts.

Lysosomes

The cell's "garbage disposal" in animal cells containing digestive enzymes to break down waste, food particles, and invading viruses.

Peroxisomes

Responsible for oxidizing fatty acids and amino acids; uses catalase to convert harmful hydrogen peroxide into water and oxygen.

Mitochondria

The site of ATP synthesis with a double membrane including cristae; contains DNA inherited exclusively from the mother.

Plastids

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

Centrosome

The main microtubule-organizing center composed of a protein matrix and two barrel-shaped centrioles.

Cilia

Short, hair-like appendages on the surface of eukaryotic cells that perform back and forth beating for movement or moving mucus.

Flagella

Long, threadlike, whip-like appendages used for propeller-like motion to move the cell.

Cytoskeleton

A network of protein filaments (microfilaments, intermediate filaments, and microtubules) acting as scaffolding and a transit system.

Microvilli

Finger-like cellular membrane protrusions that drastically increase a cell's surface area.

Prokaryotic Cells

Small ($0.1\, \text{to}\, 5.0\, \mu\text{m}$) and simple unicellular organisms with no nucleus and circular DNA; examples include bacteria.

Eukaryotic Cells

Large ($10\, \text{to}\, 100\, \mu\text{m}$) and complex cells with a membrane-bound nucleus and linear DNA; examples include animal and plant cells.

Hemoglobin

The substance that carries oxygen and carbon dioxide, given more space in red blood cells due to their lack of a nucleus.

Acrosome

A part of the sperm cell head containing enzymes necessary to penetrate the egg during reproduction.

Binary Fission

The process by which a single bacterial cell divides into two identical cells.