Lecture 4,5 bio

Abiotic Synthesis

of monomers abiotic no living source

Four steps of abiogenesis

1. Abiotic synthesis of monomers; 2. Formation of organic macromolecules; 3. Formation of protocells; 4. Appearance of self-replication

Requirement for abiotic synthesis: oxygen

no oxygen, E source, chemical precursors, lots of time

Oparin-Haldane hypothesis

Proposed that abiotic synthesis occurred on Earth's surface or in shallow water

Iron-sulfur hypothesis

Proposed that abiotic synthesis occurred under the ocean near hydrothermal deep-sea vents

Formation of organic macromolecules

form on clay or rock surfaces

Role of metal ions in macromolecule formation

Zn2+ and Fe2+ can catalyze polymerization

Experimental evidence for macromolecule formation

Formation of polypeptides, nucleic acids, and vesicles

Vesicle

A fluid-filled compartment surrounded by a lipid membrane (spontaneous)

Protocell

An abiotically produced structure containing organic macromolecules, especially a vesicle

attributes of living cells in protocells

electrical potentional across surface, absorbs material, unique internal chemical environment, dividies

What mechanism does protocells not have

heredity

Self-replication

DNA to RNA to Protein

First nucleic acid

RNA

RNA-Peptide World hypothesis

RNA was the first nucleic acid and early life used RNA to store and copy genetic information

Ribozymes

RNA enzymes that cut, catalyze

Why inst life constantly forming

because living things already exist and gets consumed instantly after formation

First cells

Prokaryotic cells that lacked a nucleus

Anaerobic organisms

do not use or need oxygen

heterotrophs

obtained organic molecules from their environment

Autotrophy

The ability to use energy, such as sunlight, to make one's own food

What did first autotrophs release

sulfur

Cyanobacteria

first to release oxygen

Oxygen Revolution

The rise in atmospheric oxygen caused by oxygenic photosynthesis

What was the result of oxygen

killed most organsims

Eukaryotes

Cells with a nucleus and membrane-bound organelles

Endosymbiosis

big cell eats small cell

Early eukaryotic cell formation

A larger cell engulfed smaller cells that became incorporated as organelles

prokaryotes lecture 5

have cell wall

Nucleoid

place where DNA hangs out

Eukaryotic

contain membrane-bound organelles

Common features of all cells

Plasma membrane, unique internal environment, genetic information storage/replication/transmission, divide, metabolism, and interaction with the environment, limited in size

Advantage of a large surface-area-to-volume ratio

It allows efficient movement of materials into and out of the cell

Similarities between prokaryotes and eukaryotes

Both have a plasma membrane and ribosomes

Nucleus

Contains most of the cell's DNA

Nuclear envelope

A double membrane surrounding the nucleus

Nuclear pores

Protein complexes that regulate transport into and out of the nucleus

Mitochondria

carry out aerobic respiration

Mitochondrial big 2

outer, inner

Chloroplasts

Photosynthetic eukaryotes

Chloroplast big 3

outer, inner, and innermost

binary fission

bacteria cells divide how

Evidence for endosymbiosis

Mitochondria and chloroplasts have multiple membranes and size similar to bacteria

Ribosomes

make proteins

Where ribosomes are found

in all cells

Are ribosomes membrane-bound?

No;

Ribosome locations

cytoplasm or attached to the ER

Ribosome composition

made of protein and RNA

Endomembrane system

divides the cell into compartments and allows membrane communication and transport

Endoplasmic reticulum (ER)

An internal membrane complex connected to the nuclear envelope

Smooth ER job

in lipid making and metabolism

Rough and smooth ER relationship

connected with lumen

Golgi apparatus

modifies and transports proteins

Vacuoles

storage;

Lysosomes

Compartments containing hydrolytic/digestive enzymes

Lysosome activation

by fusing with a food vacuole