BIO 202- LEC 6

Comprehensive vocabulary flashcards generated from Chapter 6 of Campbell Biology, covering membrane topology, vesicle transport, plant cell features, endosymbiont theory, mitochondria, chloroplasts, peroxisomes, and cell fractionation techniques.

Membrane Topology

The structural orientation describing which side of a membrane a molecule or protein domain faces, distinguishing the cytosolic face from the non-cytosolic or luminal face.

Exocytosis

A process where vesicles formed within the endomembrane system fuse with the plasma membrane, releasing their luminal contents into the extracellular space.

Plasma Membrane Budding

The process by which vesicles form at the plasma membrane and are released into the extracellular space, carrying cytosolic contents inside while preserving leaflet orientation.

Endocytosis

A cellular process in which the plasma membrane invaginates and buds inward to form vesicles that transport extracellular material into the cell.

Phagocytosis

A specialized form of endocytosis in which the plasma membrane extends around and engulfs large particles, such as microorganisms or cell debris, forming a phagosome.

Cell Wall

An extracellular structure present in plant cells, prokaryotes, fungi, and some protists that protects the cell, maintains its shape, and prevents excessive water uptake.

Primary Cell Wall

A relatively thin and flexible cell wall layer secreted first by a growing young plant cell.

Middle Lamella

A thin layer found between primary cell walls of adjacent plant cells that contains sticky polysaccharides called pectins.

Secondary Cell Wall

A strong, durable protective layer added between the plasma membrane and the primary cell wall in some mature plant cells.

Plasmodesmata

Channels passing through plant cell walls that connect the cytoplasm of adjacent plant cells, allowing water, ions, and signaling molecules to pass directly between cells.

Central Vacuole

A large plant cell organelle that holds sap, serves as a repository for inorganic ions such as potassium and chloride, and plays a key role in cell growth.

Endosymbiont Theory

The evolutionary theory proposing that mitochondria and chloroplasts originated when an early eukaryotic ancestor engulfed non-photosynthetic and photosynthetic prokaryotes.

Cristae

Infoldings of the inner mitochondrial membrane that provide a large surface area for enzymes involved in ATP synthesis during cellular respiration.

Mitochondrial Matrix

The inner compartment enclosed by the inner mitochondrial membrane containing mitochondrial DNA, ribosomes, and enzymes catalyzing metabolic steps of cellular respiration.

Chloroplast

A double-membrane organelle found in plant cells and algae that contains chlorophyll and carries out photosynthesis.

Thylakoids

Flattened, interconnected membranous sacs inside chloroplasts that are stacked into grana and convert light energy into chemical energy.

Stroma

The fluid portion of the chloroplast surrounding the thylakoid membrane system.

Plastids

A family of closely related plant organelles that includes chloroplasts, chromoplasts, and amyloplasts.

Peroxisome

A single-membrane metabolic compartment containing enzymes that remove hydrogen atoms from substrates and transfer them to oxygen, generating hydrogen peroxide ($H_2O_2$).

Catalase

An enzyme present in peroxisomes that converts harmful hydrogen peroxide ($H_2O_2$) into water ($H_2O$) and oxygen ($O_2$), or uses it to oxidize other substrates.

Cell Fractionation

A laboratory technique that breaks open cells and isolates major organelles and structural components based on their physical properties like size and density.

Differential Centrifugation

A method of cell fractionation using sequential centrifugation steps at increasing speeds to isolate specific organelles into distinct pellets.