Origin of cells, important experiments, prokaryotes and eukaryotes

Differences in prebiotic and abiotic earth

Prebiotic

• no oxygen

• more co2

• same methane

Mr. H. Gren —> what makes things alive

Metabolism

Mr. H. Gren —> what makes things alive

Response to enviornment

Mr. H. Gren —> what makes things alive

Homeostasis

Mr. H. Gren —> what makes things alive

Growth

Mr. H. Gren —> what makes things alive

reproduction

Mr. H. Gren —> what makes things alive

excretion

Mr. H. Gren —> what makes things alive

nutrition

Spontaneous generation

abiogenesis

cells come from preexisting life

biogenesis

• wanted to disprove spontaneous generation theory

• did so by putting meat in a covered and uncovered jar

  • assumed that if abiogenesis were true, both would have maggots

• proved that life doesn’t just poof out of nowhere

Francesco Redi’s experiment

• believed that there were microorganisms in the air, wanted to prove it

• he sterilized two flasks by boiling them and then added an agar broth

• he had two swanneck flasks, one broken and one unbroken (Swanneck flasks prevent microorganisms from entering)

• hypothesized that the unbroken one would remain sterile while the broken one would become contaminated + have growths

• became known as the Germ Hypothesis

Louis Pasteur’s experiment

goal: to prove that simple chemicals could form complex molecules under prebiotic conditions (aka step 1 of the abiogenesis theory of life)

Results: amino acids made

Conclusion: it is possible that life could be formed by chemicals

Limitations: we don’t know the actual chemical composition of prebiotic earth, each time the experiment is done there are different results

Stanley Miller and Urey’s experiment

1. cells come from cells

2. all living things are made by cells

3. cells are the smallest examples of life

Tenants of cell theory

example of cell theory being not 100% accurate

• has more than one nucleus in a cell bc they fuse together

Striated muscle

example of cell theory being not 100% accurate

• are enucleated after maturation

red blood cells

example of cell theory being not 100% accurate

• dna not in a nucleus, rather in Hyphae

Mold (Rhizopus)

(DFOV #1 x Mag #1)/(Mag #2)

DFOV of #2

(DFOV in micrometers)/(the number of times it fits across the field)

Object size

(Drawing size)/(object size)

Drawing magnification

1 cm

10 millimeters

1 millimeter

1000 micrometers

1 cm

1 × 10⁷ nanometers

1 cm

1 × 10¹⁰ picometers

• double membraned

• contains genetic material

Nucleus

• surrounded by ribosomes

• made of cisterna

• synthesize proteins for secretion from the cell

Rough Endoplasmic Reticulum

• No ribosomes

• used to synthesize lipids, phospholipids, and steriods

Smooth endoplasmic reticulum

• processes proteins from rough er

Golgi apparatus

• excretes waste, preforms photolysis, contains digestive enzymes

Lysosome

• where cellular respiration takes place

• ATP → glucose

Mitochondria

• has stacks of thylakoids → aka grana

• where sunlight → glucose

chloroplasts

transport

Vacuole and Vesicles