Chapter Four: Origin and General Features of Cells Flashcards
The Cell Theory (3)
- Cells are the fundamental unit of life
- All organisms are composed of Cells
- All cells come from preexisting cells
As cells increase in volume the surface area also increases, but at a ___________ rate.
lesser
The cell’s ____________ determines its metabolic activity.
volume
The cell’s ________ ________ determines the rate of transport into and out of the cell.
surface area
As a cell grows, its ____________ ____________ increases, but at a rate faster than the increase in surface area.
Metabolic Activity
Magnification makes something ___________
larger
resolution makes something _____________
clearer
Microscopes increase both the ____________ and _____________ of objects
magnification and resolution
The ability to see two objects as two instead of one object
Resolution
What kind of microscope uses light passing through the sample to observe objects?
Light Microscope
200 nm (2 x 10^-4 mm) is the resolving power for what microscope?
Light Microscope
What kind of microscope uses an electron beam passing through the sample to view objects?
Transmission Electron Microscope
What kind of microscope’s resolving power is 0.2 nm (2 x 10^-7 mm)
Transmission Electron Microscope
Cells must be killed and stained with heavy metals to block the electron beam in what microscope?
Transmission Electron Microscope
What microscope coats the surface of the sample with heavy metal stains, then uses an electron beam to scan the surface and obtain more of a 3D view of the surface?
Scanning Electron Microscope
What microscope’s resolution is about 10nm?
Scanning Electron Microscope
Life requires an interaction between what three things?
- DNA
- RNA
- Protein
What are the four proposed stages of the origin of life?
- production of nucleotides and amino acids
- polymerization of these monomers into polymers
- enclosing the polymers in membranes
- membrane-bound photocells acquire cellular properties
What did Oparin and Haldane propose in the 1920s?
Nucleotides and Amino Acids were produced spontaneously under early earth conditions
Oparin and Haldane suggested that monomers were produced and accumulated in what is called a “____________ __________”
Primordial Soup
In the 1950s, geologists suggested the early Earth’s atmosphere was a reducing one consisting of what three molecules?
- Water Vapor
- Hydrogen
- Ammonia
It is important there was no free ___________, since that would destroy any organic molecules produced.
Oxygen
What did Stanley Miller produce in 1953?
An enclosed system which circulated reducing gases in which a spark produced an energy source and produced simple organic molecules
Those who have suggested that Miller is wrong says that the atmosphere is composed mostly of what 5 molecules?
- Carbon Monoxide
- Carbon Dioxide
- Nitrogen
- Sulfur Dioxide
- Water
The mixture of the five atmospheric molecules gives less diversity and __________ yields of amino acids.
lower
UV light would destroy _____________ and _____________, preventing their accumulation in an early atmosphere.
Methane and Ammonia
Other scientists suggest that _____________ could have brought sufficient amounts of organic molecules to Earth.
Meteorites
Other scientists suggest molecules would form at the edge of ________ ______ _______ where super-heated gasses are vented.
Deep Sea Vents
Chemically the ________ Phosphodiester linkage is preferred over the _________ linkage.
5 prime - 2 prime
5 prime - 3 prime
Has Ribose been proven possible under any of the conditions expected in early Earth system?
No
Where does Steve Benner propose RNA is formed and how it comes to Earth?
It was formed on Mars and came to Earth on meteorites
Monomers attach together to form…
Polymers
Hydrolysis would compete with __________________ reactions (polymerization)
Condensation
Water promotes ________________ removal
depurination/base
It is unlikely that ______________ would occur in aqueous environments, but rather on solid surfaces
Polymerization
Many ________ bind Nucleotides and Amino Acids.
clays
__________ can position Nucleotides to connect the phosphate of one with the Ribose of another.
Cations
Cations favor the use of _________ over T and C
A and G
Cations favor _________ over A and G
Inosine
Clays promote ____________ in presence of water
decomposition
A normal peptide bond requires a ___________ to insure correct bond formation
Ribosome
Side chain of _______ ________ can bond to the side chain, amino or carboxyl of another
amino acids
Majority of bonds formed abiotically are NOT _________ _________.
Peptide Bonds
________________ _________ or Phosphate group of one can attach to any of the four hydroxyl groups of Ribose
Nitrogenous Base
If polymers were formed, they would have to be enclosed in _____________ and develop the ability to reproduce
membranes
Organic molecules would need to be __________ from the external environment.
separated
They would eventually need _________ __________ to create new polymers and harness energy
enzymatic functions
If phospholipids are dissolved in water, they form __________
Liposomes
If Liposomes form near ______ it can be incorporated into the Liposome.
RNA
RNA that isn’t incorporated into the Liposome requires ___________ ______________.
protein transporters
_____% of all proteins function in membranes
30
Are membranes made from scratch?
No
All membranes come from ___________ _____________.
preexisting membranes
Favored models of the production of cells propose an “__________ world”
RNA
According to favored models, RNA can do what 3 things?
- function as genetic material
- function as enzymes
- reproduce
the minimum complexity needed to maintain the processes in the simplest cells is defined as…..
Irreducible Complexity
Cells need a minimum of _______ genes
493
DNA replication in simplest prokaryotes requires _____ enzymes and _______ polypeptides
14 and 25
DNA cannot replicate without ________
proteins
proteins cannot be produced without _______ and __________
DNA and RNA
What are the two domains of prokaryotic cells?
Eubacteria and Archaebacteria
Name the three characteristics of Prokaryotic Cells:
- lack membrane-bound organelles
- are relatively simple in structure
- are generally smaller than eukaryotic cells
Name the structure and function of the PLASMA MEMBRANE
single membrane
regulate transport
Name the structure and function of a NUCLEOID
Aqueous
Heredity
Name the structure and function of the CYTOPLASM
Aqueous
Biochemical Reactions
Name the structure and function of RIBOSOMES
Solid - RNA and Proteins
Protein Synthesis
Name the structure and function of the CELL WALL
Peptidoglycan Membrane
Protection/Support
Name the structure and function of a CAPSULE
Polysaccharides
Protection/Hydration
Name the structure and function of the FLAGELLA
Solid - Proteins
Movement