Chapter 24a

These flashcards cover key concepts related to the early life conditions and characteristics of prokaryotes as outlined in the lecture notes.

Prokaryotes

The most abundant organisms on earth, which can live in extreme and normal environments.

Stromatolites

Layered rocks formed from the activities of prokaryotes, dating back to 3.5 billion years ago.

Primordial soup

A hypothesized solution of organic molecules in Earth's early oceans, suggested by Oparin and Haldane.

Protocells

Fluid-filled vesicles with a membrane-like structure that exhibit certain properties of life.

Ribozymes

RNA molecules that can catalyze chemical reactions, important in the context of early life.

Gram-positive bacteria

Bacteria that have a simpler cell wall structure with a large amount of peptidoglycan, appearing purple or blue when stained.

Gram-negative bacteria

Bacteria with complex cell walls that are less peptidoglycan-rich and often have an outer membrane, appearing pink when stained.

Autotrophs

Organisms that can make their own food, such as photoautotrophs and chemoautotrophs.

Heterotrophs

Organisms that cannot make their own food and must consume organic compounds.

Obligate aerobes

Organisms that require oxygen for cellular respiration.

Obligate anaerobes

Organisms that are poisoned by oxygen and use anaerobic respiration.

Facultative anaerobes

Organisms that can use oxygen if it is available but can also survive without it.