Chapter 2

Cytology

The study of cells.

Microscopy

The technique used to view small objects, such as cells.

Light microscope (LM)

A type of microscope that uses visible light to produce an image.

Magnification

The increase in viewable size of an object.

Resolution

The ability to reveal detail in an image.

The Cell Theory

A fundamental concept stating that all organisms are made of cells, all existing cells are produced by other living cells, and the cell is the most basic unit of life.

Plasma membrane

The boundary that surrounds a cell.

Phospholipids

The primary component of the lipid bilayer, making up 75% of the plasma membrane.

Lipid bilayer

A double layer of phospholipids that forms the plasma membrane.

Cholesterol

A component of the plasma membrane that increases its fluidity, making up 20% of the membrane.

Glycolipids

Molecules made of glucose and phospholipids that are involved in cell signaling and recognition, constituting 5% of the plasma membrane.

Integral proteins

Membrane proteins that pass through the lipid bilayer.

Glycoproteins

Proteins that have carbohydrate groups attached, found on the membrane surface.

Peripheral proteins

Membrane proteins that adhere to one face of the membrane.

Glycocalyx

A dense, gel-like meshwork surrounding the cell that acts as a physical barrier.

Villi & Microvilli

Cell surface extensions that increase surface area.

Cilia

Motile microtubules that help in movement.

Flagella

Long structures that propel sperm cells.

Cellular Junctions

Structures that facilitate attachments between cells.

Tight junction

A type of cellular junction that acts as a sealant.

Desmosomes

Cellular junctions that resist stress.

Gap junction

A type of junction that allows communication between cells.

Cell cytoskeleton

A network of fibers that supports the cell, determines its shape, organizes contents, and facilitates movement.

Microfilaments

The smallest components of the cytoskeleton, primarily made of actin, supporting the plasma membrane.

Intermediate filaments

Thicker components of the cytoskeleton that provide strength to cells and tissues.

Microtubules

The largest components of the cytoskeleton that hold organelles in place and guide their movement.

Endoplasmic Reticulum (ER)

An organelle involved in the synthesis of proteins and lipids.

Rough endoplasmic reticulum (RER)

Studded with ribosomes, it produces proteins and phospholipids.

Smooth endoplasmic reticulum (SER)

Involved in detoxification and steroid synthesis.

Ribosomes

Organelles that read mRNA and assemble amino acids into proteins.

Golgi Complex/Apparatus

An organelle that modifies, sorts, and packages proteins for secretion.

Lysosomes

Organelles that contain enzymes for breaking down cellular waste.

Autophagy

The process by which lysosomes break down organelles.

Apoptosis

Programmed cell death facilitated by lysosomes.

Proteasomes

Cylindrical organelles that degrade old proteins.

Mitochondria

Organelles specialized for aerobic respiration and ATP production.

Centrioles

Structures made of microtubules that are active during cell division.

Nucleus

The largest organelle that contains chromosomes and acts as the genetic control center.

The Cell Cycle

The series of phases that a cell goes through in preparation for division.

Mitosis

The phase of the cell cycle where nuclear material divides, consisting of prophase, metaphase, anaphase, and telophase.