Chapter 2 Cell Biology Flashcards

Vocabulary flashcards covering fundamental concepts in cell biology including cell structures, membrane components, transport mechanisms, organelles, and cell cycles based on Chapter 2 lecture notes.

Cell Theory

The principle that all organisms are composed of one (single-celled) or more (multicellular) cells.

Eukaryote

A cell type containing a true nucleus (meaning 'after the nucleus').

Prokaryote

A cell type lacking a true nucleus (meaning 'before the nucleus').

Viruses

Obligate intracellular parasites that have no cell membrane and need a host to survive.

Plasma Membrane

A thin and selective outer membrane of the cell composed primarily of lipids and proteins.

Phospholipids

Bipolar molecules featuring a hydrophilic (polar) part that loves water and a hydrophobic (nonpolar) part that hates water.

Peripheral Proteins

Proteins that are not embedded in the lipid bilayer, but are on the edge or loosely attached to the external or internal surface of the plasma membrane.

Integral Proteins

Transmembrane proteins embedded in the phospholipid bilayer that form a tunnel or channel extending through the entire membrane.

Cholesterol (Membrane Component)

Lipid that makes up about $20\%$ of all membrane lipids; it strengthens and stabilizes the cell membrane against extreme temperatures.

Glycolipids

Lipids constituting about $5\text{--}10\%$ of membrane lipids that have carbohydrate molecules attached facing outward.

Glycocalyx

A structure on the external surface of the cell membrane formed by glycoproteins and glycolipids.

Passive Transport

Transport across the plasma membrane moving down a concentration gradient (high to low) that does not require cell energy.

Active Transport

Transport across the plasma membrane from low to high concentration that requires cellular energy in the form of ATP.

Simple Diffusion

A passive transport process where small or nonpolar molecules move from high to low concentration.

Osmosis

The passive transport of water ($[H_2O]$) moving from high to low concentration.

Facilitated Diffusion

Passive transport from high to low concentration with the assistance of a transport protein.

Sodium-Potassium Pump

A pump mechanism where potassium is kept high in the cell while sodium is continuously kicked out.

Exocytosis

A bulk transport process that exports substances using phospholipid vesicles (such as the release of macromolecules into the pancreatic duct).

Endocytosis

A bulk transport process by which large amounts of substances are imported into the cell.

Phagocytosis

A type of endocytosis referred to as 'cell eating' where particles are engulfed by pseudopodia.

Pseudopodia

'False feet' originating from the plasma membrane that surround, engulf, and suck particles into the cell.

Pinocytosis

A type of endocytosis referred to as 'cell drinking.'

Receptor-Mediated Endocytosis

A form of endocytosis that involves engulfing specific molecules that are bound to receptors.

Cytoplasm

All materials located between the plasma membrane and the nucleus, consisting of cytosol and organelles.

Cytosol

The fluid-based component (fluid only) of the cytoplasm.

Smooth ER

Part of the endoplasmic reticulum with a smooth appearance; functions in lipid synthesis, transport, and storage, carbohydrate metabolism, and detoxifying drugs, alcohol, and poisons.

Rough ER

Part of the endoplasmic reticulum with walls studded with ribosomes; functions to synthesize, transport, or store proteins for secretion, membrane incorporation, or lysosome creation.

Lysosomes

Organelles that digest materials that enter the cell by endocytosis.

Golgi Apparatus

An organelle responsible for modification, packaging, and sorting of new proteins and materials for lysosomes, secretion, and plasma membrane incorporation.

Mitochondria

Organelles responsible for generating ATP by the process of cellular respiration.

Cytoskeleton

Non-membrane bound organelle composed of microfilaments, intermediate filaments, and microtubules that maintains and changes cell shape, supports the cell, and assists with motility functions.

Nuclear Envelope

A double membrane that separates the nucleus from the cytoplasm.

Nuclear Pores

Openings in the nuclear envelope that allow materials to move back and forth between the cytoplasm and nucleus.

Nucleolus

An area of the nucleus that helps regulate the synthesis of ribosomes.

Chromatin

DNA that exists in an unwound state.

Interphase

The maintenance phase of the cell cycle where normal metabolic activities occur and the cell prepares for cell division.

Mitotic Phase

The phase of the cell life cycle during which the cell divides.

Necrosis

Irreversible cell damage caused by harmful agents that are often external.

Apoptosis

Programmed cell death.