Lecture 2: The Cell

Sex cells

Germ cells (gametes) for reproduction, including sperm and oocytes.

Somatic cells

Cells that are NOT sex cells; all other cells in the body.

Plasma Membrane

A dynamic structure that consists of a bilayer and multiple components, including phospholipids, glycolipids, and proteins.

Cytoplasm

The material within a cell, excluding the nucleus, consisting of cytosol and organelles.

Cytosol

Intracellular fluid of the cell; gel-like substance inside the cell.

Organelles

Intracellular structures that perform specific functions within the cell.

Membrane Permeability

The ability of the plasma membrane to regulate the exchange of materials with the environment.

Passive processes

Processes where molecules move from high to low concentration without the use of ATP.

Diffusion

Movement of molecules from an area of high concentration to an area of low concentration.

Osmosis

Movement of water across a membrane.

Facilitated diffusion

Movement of molecules across a membrane via protein channels.

Active processes

Processes that require ATP to move molecules from low to high concentration.

Endocytosis

Process by which cells take in molecules, including cell drinking (pinocytosis) and cell eating (phagocytosis).

Exocytosis

Process by which cells expel materials.

Microvilli

Extensions of the plasma membrane that increase surface area for absorption.

Intracellular fluid (ICF)

Fluid found inside the cell, contributing to the cytosol.

Cell-to-cell communication

The ability of cells to communicate with each other through the plasma membrane.

Structural support

The function of the plasma membrane in providing support to the cell.

Sensitivity to changes

The plasma membrane's ability to respond to changes in the extracellular fluid.

Cholesterol

A component of the plasma membrane that helps maintain its structure.

Peripheral proteins

Proteins located on the outer or inner surface of the plasma membrane.

Integral proteins

Proteins that are embedded within the plasma membrane.

Cytoskeleton

A crucial structure for cell movement, shape maintenance, and endocytosis.

Microfilaments

Thin filaments composed of actin that are involved in cell movement.

Intermediate filaments

Filaments that help maintain cell shape.

Microtubules

Thick filaments composed of tubulin that are involved in intracellular transport and cell division.

Centriole

An organelle that produces microtubules to move chromosomes during cell division.

Cilia

Short organelles that beat rhythmically to move fluid or secretions across the cell surface.

Flagella

Long organelles that propel sperm through fluid.

Ribosomes

Organelles that float in the cytoplasm or are attached to the endoplasmic reticulum, involved in protein production.

Endoplasmic reticulum

An organelle involved in the production of proteins and lipids.

Mitochondria

Double-layered membraned organelles that produce ATP, the primary energy currency of the cell.

Nucleus

The control center of the cell that contains chromosomes.

Chromatin

Loosely coiled DNA in non-dividing cells that forms a tangled network.

Sister chromatids

Identical copies of a chromosome that are joined at the centromere.

Centromere

The region of a chromosome where sister chromatids are joined and spindle fibers attach during mitosis.

Kinetochores

The region of the centromere where spindle fibers attach during mitosis.

Golgi apparatus

An organelle that functions as the post office of the cell, modifying and packaging proteins.

Lysosome

An organelle that contains enzymes for waste processing and detoxification.

Cell junctions

Structures that connect cells to each other, including gap junctions and tight junctions.

Tight junctions

Cell junctions that prevent leakage of fluids between cells.

Desmosomes

Cell junctions that provide strong adhesion between cells.

Interphase

The phase of the cell cycle where the cell prepares for division.

Mitosis

The process of cell division that results in two identical daughter cells.

Cytokinesis

The division of the cytoplasm that occurs after mitosis.