bio lecture 2

Vocabulary flashcards covering endosymbiotic origin of chloroplasts and mitochondria, plant phylogeny, and key plastid-related traits discussed in the lecture notes.

Primary endosymbiosis

Origin of the eukaryotic chloroplast from a symbiotic cyanobacterium; produced the first photosynthetic eukaryotes in red algae, green algae, and land plants.

Chloroplast

Organelle in photosynthetic eukaryotes derived from cyanobacteria via primary endosymbiosis; typically with two membranes in plants.

Cyanobacterium

The ancestral bacterium that became the chloroplast through endosymbiosis.

Endosymbiosis

A relationship in which one cell is engulfed by another; explains origins of mitochondria and chloroplasts.

Peptidoglycan in chloroplasts

Wall component retained in chloroplasts of some lineages (notably glaucophytes), indicating bacterial ancestry.

Glaucophytes

Freshwater algae whose chloroplasts retain peptidoglycan, linking plastids to cyanobacteria.

Primary plastids

Chloroplasts derived from primary endosymbiosis; found in red algae, green algae, and land plants.

Red algae

Algae with chlorophyll a and phycoerythrin; among the first groups with primary plastids.

Green algae

Chloroplast-containing algae with chlorophylls a and b; sister to land plants within the green lineage.

Streptophytes

Clade including charophyte green algae, Coleochaetophytes, other green algae, and land plants; features include phragmoplasts and plasmodesmata.

Charophycean green algae

Charophycean algae within the green lineage; close relatives of land plants.

Coleochaetophytes

Group of green algae closely related to land plants; part of the Streptophytes.

Oogamy

Sexual reproduction with a large, non-motile egg and a small motile sperm.

Plasmodesmata

Channels through cell walls that connect adjacent plant cells; enable transport and signaling.

Phragmoplast

Microtubule-ER scaffold that guides cell plate formation during division in many streptophytes.

Apical growth

Growth at the tips of shoots and roots; promotes elongation and branching.

Desmotubule

ER-derived tube within plasmodesmata facilitating intercellular transport.

Mitochondria

Organelle of endosymbiotic origin; older than chloroplasts and present in all eukaryotes; has its own genome.

Plastid genome

Chloroplast contains its own circular genome separate from the host nucleus, evidence for endosymbiosis.

Secondary endosymbiosis

Engulfment of a photosynthetic eukaryote by another eukaryote; often yields chloroplasts with additional membranes.

Tertiary endosymbiosis

A later endosymbiotic event where a eukaryote with a secondary plastid is engulfed by another eukaryote.

Floridean starch

Starch stored by red algae; differs from red algae starch.

Chlorophyll a & b

Pigments enabling photosynthesis in green plants; chlorophyll a is universal; b is an accessory pigment.

Two membranes in chloroplasts

Characteristic of primary plastids; chloroplasts are bounded by a host-derived outer membrane and an inner membrane.