Exam 1 Review Material

Chapters 17 - 21

the Big Bang Theory

the universe began in a single instant 13 to 15 billion years ago. all existing matter and energy suddenly appeared and spread outward, gas condenses to form stars, planets formed from build up of dust and debris.

Precambrian Era

from Earth’s formation through about 90% of its history

Hadeon eon

hell-like, little to no oxygen

evidence of early water

zircon crystals 4.4 billion years ago provide the earliest of this…

Earth’s early atmosphere

was oxygen free

the organic subunits of life

amino acids, fatty acids, nucleotides, simple sugars

hypothesis of lightning fueled atmospheric reactions

fill a chamber with gases and zap with electricity, organic molecules formed

delivery from space hypothesis

meteorites that fell to earth held the molecules of life

reactions at hydrothermal vents hypothesis

the anaerobic environment of hydrothermal vents produced molecules of life

polymers to protocells

hypothesis of the earliest cells formed in a stepwise process beginning with inorganic materials

iron sulfur world hypothesis

life originated at deep-sea hydrothermal vents

RNA world hypothesis

RNA may have been first molecule to store genetic information

ribozyme

RNA can function like an enzyme in protein synthesis

protocell

Membrane-enclosed collection of interacting molecules that can take up material and replicate. permeability very well.

LUCA

last common universal ancestor, prokaryotic. Not the first cellular life, but the last shared ancestor of modern life

oldest cell microfossils

from canadian rocks \~3.77 billion years old

cyanobacteria

 Oxygenation of Earth’s atmosphere was due to oxygen-releasing photosynthesis in

Oldest agreed-upon eukaryotic fossils are about

**1.8 billion years old**

protists

first eukaryotes

endosymbiont hypothesis

origin of mitochondria

endosymbiont

any organism that lives within the body or cells of another organism most often, though not always, in a **mutualistic relationship**

Nearly all eukaryotes have mitochondria, but only some have chloroplasts

so they were acquired independently

pathogen

cellular organism or virus that causes disease in its host.

virus

Noncellular, infectious particle that can replicate only in a living cell (its host), genome may be DNA or RNA

bacteriophages

 Viruses that infect bacteria and inject their DNA

naked virus

are spherical viruses with **protein coat** having spikes.

enveloped virus

DNA or RNA Virus with an envelope made of lipid membrane derived from host cells. AIDS

retrovirus

a virus whose RNA genome is used as a template to produce

emerging viral diseases

those that have been only recently detected in humans or are now expanding their range. HIV,Zika, Ebola

prokaryotes

cells without a nucleus

bacteria cell shapes

rod, sphere, spiral

flagellum

Rotates like a propeller; does not contain microtubules, does not bend side to side

pili

hairlike filaments used to stick to surfaces and move