Behavioural Biology B11: Compartmentalizing & Border crossing - The what, where and how of a Cell

Flashcards covering key vocabulary related to cell structure, function, and membrane transport mechanisms as discussed in the Behavioural Biology B11 lecture notes 'The what, where and how of a Cell'.

Cell

The smallest living unit that is capable of performing all the activities of life.

Prokaryotic Cells

Organisms like bacteria and archaea, characterized by being 1-10 μm across, lacking membrane-bound organelles, having circular DNA in the cytoplasm, and rare internal membranes.

Eukaryotic Cells

Organisms like plants, animals, fungi, and protists, characterized by being 10-100 μm across, possessing membrane-bound organelles, coiled linear DNA in the nucleus, and many internal membranes.

Cell Size Limitation

Limited by the surface-to-volume ratio; the volume that can be nourished by materials passing through the surface membrane cannot be exceeded.

Cell Structure Reflects Function

The anatomy of a cell is specialized to perform its physiological role (e.g., red blood cells, sperm cells, egg cells).

Plasma Membrane

Separates the inside of the cell from the external environment, provides structural support, and regulates the movement of nutrients and wastes into and out of the cell.

Cytoplasm

A thick, transparent fluid that fills the area between the plasma membrane and the nucleus, also containing organelles.

Organelles

Specialized structures within the eukaryotic cell, compartmentalized into membrane-bound units, each having different functions.

Nucleus

The cell control center that contains genetic information (DNA) in the form of genes (collectively called the genome) and directs all activities of the cell.

Genome

The collective term for all the DNA and genes contained within the nucleus of an organism.

Chromosomes

DNA within the nucleus associated with proteins and organized into linear strands; they shorten and condense during cell division. Humans have 46 chromosomes (23 pairs).

Chromatin

The extended form of chromosomes when the cell is not undergoing division.

Gene

A section of DNA that codes for a unique protein, which in turn contributes to a unique phenotype (physical characteristic).

Nuclear Envelope

A membrane surrounding the nucleus that allows communication between the nucleus and cytoplasm via nuclear pores.

Endoplasmic Reticulum (ER)

A network of canals that accounts for more than half of the total membrane in many eukaryotic cells, continuous with the nuclear envelope, and involved in transporting newly made proteins from ribosomes to the Golgi complex.

Rough ER

Endoplasmic Reticulum that has membrane-bound ribosomes, produces proteins and lipid membranes, and serves as a membrane factory for the cell.

Smooth ER

Endoplasmic Reticulum that lacks ribosomes, is rich in enzymes, synthesizes lipids, phospholipids, and steroids, metabolizes carbohydrates, stores calcium, and detoxifies poisons.

Golgi Complex (Golgi apparatus/body)

Flattened membrane sacs that process, sort, and modify proteins for export or cell use, and package materials into transport vesicles.

Lysosome

An organelle responsible for intracellular digestion of bacteria, lipids, proteins, and worn-out or faulty organelles (autophagy); it is acidic inside and contains over 40 enzymes.

Autophagy

The process by which lysosomes engulf and break down damaged organelles, recycling their molecules for the construction of new organelles.

Vesicles

Hollow spherical organelles, surrounded by a membrane, produced by the ER and Golgi, used to store and/or transport chemicals throughout the cell; generally smaller than vacuoles.

Vacuole

Hollow spherical organelles, surrounded by a membrane, produced by the ER and Golgi, used to store and/or transport chemicals throughout the cell; generally larger than vesicles.

Mitochondria

The "powerhouse" of the cell; the site of cellular respiration where glucose (sugar) is converted into energy (ATP). It contains inner foldings that provide increased membrane surface for these reactions.

Cellular Respiration

The biochemical process occurring in the mitochondria where glucose (sugar) is reacted to produce energy in the form of ATP.

Phospholipid Bilayer

The fundamental double-layered structure of the plasma membrane, also known as the fluid mosaic model, which is permeable to small gas molecules, water, and lipids, but impermeable to large polar molecules and charged particles.

Fluid Mosaic Model

A model describing the structure of the plasma membrane as a dynamic phospholipid bilayer with proteins embedded in or attached to its surfaces, some of which can move sideways.

Selective Permeability

The property of the plasma membrane that allows it to regulate the movement of specific substances into and out of the cell while blocking others.

Passive Transport

A mechanism for substances to cross the plasma membrane that does not require the cell to expend energy (e.g., simple diffusion, facilitated diffusion, osmosis).

Active Transport

A mechanism for substances to cross the plasma membrane that requires the cell to expend energy (e.g., active transport, endocytosis, exocytosis).

Endocytosis

An energy-requiring process where a region of the plasma membrane engulfs a substance (large molecules, bacteria, or liquids) and then pinches off, enclosing the substances in a vesicle, to ingest them into the cell.

Phagocytosis

A type of endocytosis, often called "cell eating," where large particles or bacteria are enveloped by the cell membrane and internalized to form a phagosome or "food vacuole."

Pinocytosis

A type of endocytosis, often called "cell drinking," which involves the absorption of extracellular fluids (ECF), taking in portions of extracellular fluid and all solutes dissolved in the solution.

Exocytosis

An energy-requiring process where large molecules leave the cell; these molecules are enclosed in membrane-bound vesicles that travel to the plasma membrane, where their contents are released to the outside (e.g., neurotransmitters, hormones).