Introduction to the Cell Lesson2

Vocabulary flashcards covering basic cell structure and transport concepts from the lecture notes (Ch 1.2, 2.6, 4.1, 7.3).

Cytoplasm

The jelly-like interior of the cell, about 70-80% water, containing amino acids, sugars, and salts; stores nutrients and is the site of biochemical processes in prokaryotic cells.

Cytoplasmic membrane

A fluid membrane surrounding the cell, made of lipids and proteins; acts as a permeability barrier, anchors embedded proteins, and serves as a site for energy reactions and nutrient processing.

Lipids

Hydrophobic molecules that include triglycerides, phospholipids, and steroids.

Phospholipids

Major component of the cytoplasmic membrane; consist of a charged head, glycerol, and two fatty acid chains; have hydrophilic heads and hydrophobic tails.

Hydrophilic head

The polar, water-attracting region of a phospholipid.

Hydrophobic tails

The nonpolar fatty acid chains of a phospholipid.

Permeability barrier

Function of the cytoplasmic membrane that regulates what enters and leaves the cell.

Anchor for embedded proteins

Role of the cytoplasmic membrane in holding membrane proteins in place.

Site for energy reactions

Membrane area where energy-related reactions and nutrient processing occur.

Selective permeability

Ability of the membrane to permit some molecules to pass while blocking others, helping maintain internal conditions.

Simple diffusion

Passive transport where molecules move directly through the membrane down their concentration gradient without energy.

Facilitated diffusion

Passive diffusion that requires a carrier protein; the process is specific and rate is limited by carrier binding sites.

Passive transport

Movement of substances across the membrane without energy input, including simple and facilitated diffusion.

Active transport

Transport that moves substances against their concentration gradient; requires membrane transporter proteins and energy.

Primary active transport

Type of active transport that uses direct energy from ATP to drive transport (ATP pumps).

Membrane transporter proteins

Proteins embedded in the membrane that facilitate movement of substances, sometimes using energy.

ATP

Adenosine triphosphate; the energy currency of the cell; hydrolyzed to ADP and Pi to release energy.

Osmosis

Diffusion of water across a selectively permeable membrane; water moves toward higher solute concentration.

Hypertonic solution

An environment with higher solute concentration than inside the cell; water exits the cell and it may shrink.

Isotonic solution

An environment with solute concentration equal to that inside the cell; no net water movement.

Hypotonic solution

An environment with lower solute concentration than inside the cell; water enters the cell and it may swell.

Carrier-mediated transport

Transport via specific carrier proteins; the rate is limited by the number of available binding sites.

Group translocation

A form of active transport in which the substance is chemically modified during transport (common in bacteria).

Endocytosis

Bulk transport into the cell via vesicles; phagocytosis is a type of endocytosis.

Exocytosis

Bulk transport out of the cell via vesicles.

Bulk transport

Large-scale transport processes such as endocytosis and exocytosis.

Prokaryotic cell

One of the two main cell types; typically lacks a true nucleus and membrane-bound organelles; cytoplasm is the site of biochemical processes in these cells.

Eukaryotic cell

One of the two main cell types; contains a nucleus and membrane-bound organelles.