Exam 3 Flashcards
(259 cards)
cell biology
the study of individual cells and their interactions with each other
cell theory
- all living organisms are composed of 1+ cells
- cells are the smallest units of life
- new cells come from pre-existing cells
stages of life theory
- nucleotides and amino acids were produced prior to cells
- nucleotides became polymerized to form RNA and DNA ==> amino acids were polymerized to form proteins
- polymers became enclosed in membranes
- polymers enclosed in cell membranes acquired properties associated with living cells via chemical selection
primordial soup hypothesis
organic molecules formed spontaneously formed through prebiotic and abiotic synthesis
prebiotic soup
slow acumulation of organic molecules in the early oceans of a long period of time
reduced atmosphere hypothesis
rich in water vapor, hydrogen gas, methane, and ammonia and lacked atmospheric oxygen => redox reactions are required to form complex organic molecules
arguments against reduced atmosphere hypothesis
early earth was a neutral gaseous mixture and earth had a high UV that would destroy NH4 and NH3
extraterrestrial hypothesis and objections
molecules came from asteroids => material would be destroyed by intense heat
deep sea vent
superheated rich metal ion and hydrogen sulfide vents mixed with cold seawater => molecules are formed in the surrounding mixed water gradients
polymers like nucleotides and amino acids like to form under what conditions?
non aqueous or mild aqueous conditions
protobiont
a prebiotically produced molecule/macromolecule that acquired a boundary (lipid bilayer similarity) that allowed an internal chemical environment different from its surroundings
protobiont key features
- membrane boundary
- polymers inside containing information
- polymers having catalytic functions
- developing capability of self replication
liposome
vesicles surrounded by a phospholipid bilayer
2 special RNA properties:
stores information for self replication (1) and performance of catalytic functions (2)
ribozymes
molecules catalyzing chemical reactions
chemical selection
chemical mixtures have special advantages that cause it to increase in amounts relative to other chemicals
chemical evolution
molecules change over time to have different chemical composition
micrograph
image taken with the aid of a microscope
resolution
measure of the clarity of an image between adjacent objects
contrast
difference in light, dark, and color between adjacent regions
magnification
ratio between image size and actual size
transmission electron microscopy
electrons go through slices of a biological sample
scanning electron microscopy => heavy metal and copper crid
views surfaces of biological samples => heavy metals
prokaryotes
bacteria are 1-10 micrometer