Cell Biology: The Fundamentals of Life and Discovery

Practice flashcards covering the fundamentals of cell biology, including microscopy, cellular structures, transport mechanisms, organelles, and cell division.

Thermophiles

Unicellular, heat-loving bacteria that thrive in extreme temperatures, such as hot springs, and mirror organisms thought to have existed 3.5 billion years ago.

Puga Valley

A region in Ladakh, India, known for hot springs where research on thermophiles and mineral deposits provides insights into the early assembly of protective cell membranes.

Birbal Sahni Institute of Palaeosciences, Lucknow

The research institution whose scientists indicated that the rapid formation of calcium carbonate around hot springs protected early organic molecules.

Tissues

Groups of similar cells working together as part of the biological hierarchy.

Organs

Different tissues organized to perform a specific function within a multicellular organism.

Limit of resolution

The strategic limitation of the human eye, which can distinguish two points as separate from a distance of $25\,cm$ only if they are at least $0.1\,mm$ apart.

Light Microscope

A tool that uses visible light and glass lenses to achieve magnification typically between 100X and 400X.

Electron Microscope

A tool that uses beams of electrons to achieve extremely high magnification, revealing details at the nanometer scale.

Formula for Estimating Cell Size

$$\text{Estimated size of cell} = \frac{\text{Diameter of the visible field (in }\mu m\text{)}}{\text{Number of cells aligned along the diameter}}$$

Fluid-Mosaic Model

A model describing the plasma membrane as a lipid bilayer where molecules move flexibly and proteins are embedded as specialized gatekeepers.

Selective Permeability

A property of the cell membrane that allows only specific substances to pass while blocking others.

Cell Wall

A rigid outer layer found in plants, fungi, and bacteria that provides structural support to withstand environmental stresses.

Safranin

A specific stain used in laboratories to visualize the boundaries of plant cells, such as onion or Rhoeo peels.

Methylene Blue

A specific stain used in laboratories to visualize the boundaries of animal cells, such as human cheek cells.

Diffusion

The net movement of particles from an area of higher concentration to an area of lower concentration.

Osmosis

A specific type of diffusion involving the movement of water through a selectively permeable membrane from a dilute solution to a concentrated solution.

Hypotonic Solution

A solution with a lower solute concentration than the cell, causing water to enter the cell and resulting in swelling.

Hypertonic Solution

A solution with a higher solute concentration than the cell, causing water to leave the cell and resulting in shrinkage.

Plasmolysis

The process in plant cells where the inner contents shrink away from the rigid cell wall due to water loss in a hypertonic environment.

Cytoplasm

The jelly-like substance within the cell that contains various organelles.

Prokaryotic Cell

A simple cell type, typically $1$ to $10\,\mu m$ in diameter, that lacks a membrane-bound nucleus and specialized organelles.

Eukaryotic Cell

A complex cell type, typically $10$ to $100\,\mu m$ in diameter, characterized by a membrane-bound nucleus and specialized organelles.

Nucleus

Known as the "House of Coded Instructions," it stores DNA and contains genes that provide the genetic blueprint for cellular activities.

Genes

The functional segments of DNA stored within the nucleus.

Rough Endoplasmic Reticulum (ER)

A part of the cell's manufacturing system that contains ribosomes and is responsible for synthesizing and secreting proteins.

Smooth Endoplasmic Reticulum (ER)

A part of the cellular machinery that handles the synthesis of fats and hormones.

Golgi Apparatus

The "Packaging and Shipping Centre" of the cell that modifies, sorts, and packages proteins and lipids into vesicles.

Mitochondria

The "Powerhouse of the Cell" which produces ATP through cellular respiration to power biological work.

ATP (Adenosine Triphosphate)

The energy currency of the cell produced by mitochondria.

Chloroplasts

Plastids found in plants that contain green chlorophyll for the synthesis of food.

Chromoplasts

Plastids containing yellow, orange, or red pigments responsible for the colors of fruits and flowers.

Leucoplasts

Plastids used by plant cells to store starch, oils, or proteins.

Vacuoles

Storage and support units; in plants, the large central vacuole is filled with cell sap to maintain pressure and keep the plant firm.

Mitosis

A type of cell division resulting in two genetically identical daughter cells, used primarily for growth and tissue repair.

Meiosis

A process of cell division vital for sexual reproduction that facilitates genetic diversity.

Aceto-carmine

A stain used to observe chromosomes organizing and separating during cell division, such as in onion root tips.

Cell Culture

The process of growing cells outside of a living organism in a nutrient-rich, sterile environment with controlled temperature and pH.

Chromosomes

Rod-shaped structures made of DNA and protein that carry genetic information and become visible during cell division.