Cells and the Origin of Life

Flashcards for review on cellular biology and the theories surrounding the origin of life.

What are cells defined as in this lecture?

Cells are the smallest unit of self-sustaining life.

What are the eight life processes common to cells?

Metabolism, growth and division, response to stimuli, homeostasis, movement, reproduction, excretion, and nutrition.

What is metabolism in the context of cell function?

Metabolism refers to the chemical reactions that occur within cells.

What does homeostasis mean?

Homeostasis is the maintenance of constant internal conditions within a cell.

What is abiogenesis?

Abiogenesis is the natural process where life arose from non-living matter.

evolution of the first cells

1. non living synthesis of simple organic molecules from inorganic molecules

2. self assembly of larger more complex polymers from simple organic molecules

3. self replication of molecules

4. compartmentalisation - membranes form to enclose cell contents separate internally and externally

What is the role of compartmentalization in cells?

Compartmentalization involves membranes enclosing cell contents to separate them from the external environment.

What defines a virus compared to other life forms?

A virus is classified as non-living, requires a host to replicate, and cannot maintain a steady state independently.

• non cellular

• respond to external stimuli

• rapid mutation

What are the three common features of all cells?

A stable partially permeable membrane, genetic material, and metabolic processes.

What is a protocell? Explain theory of life

A protocell is a pre-cellular entity that had basic metabolism but no developed genetic system.

arose spontaneously - grew and divided to daughter cells

evolves adaptively acquired genetic system

difficult to prove as first protocol didn’t fossilise

Describe the concept of natural selection in evolution.

Natural selection is the process allowing organisms to evolve and reproduce, leading to genetic variation.

What is the significance of genetic molecules like RNA in the origin of life?

Smallest genetic molecules like RNA may have been part of a self-sustaining system and capable of replication.

gene first theory of origin of life

genetic molecule (rna) smallest of genetic molecules arose spontaneously- can replicate

evolved by natural selection forking genetic variations that could assemble a cell membrane and metabolise

complex rna molecules form spontaneous

show self replication and evolution

metabolism first

self sustaining system of simple reactions

feeding and energy arose spontaneously

chemical mixture evolved into cells and genetic systems for catalysis

favour this theory