Lec 1: Intro Flashcards
8 Characteristics of Life (Living Things)
- ) Grow and Develop (& die)
- ) Reproduce
- ) Metabolize
- ) Respond to Environment
- ) Maintain Homeostasis
- ) Based on Genetic Code
- ) Evolve
- ) Composed of Cells
Exceptions to living things (2)
viruses
prions
“prions” aka
Proteinaceous infectious particles
prions cause what diseases? (2)
mad-cow disease
Creutzfeldt–Jakob disease
prions =
similar to…
causes…
which disrupts…
= Infectious protein
…a normal protein
…mis-folding and accumulation of the mis-folded proteins as amyloid plaques
…cell function (neural degeneration)
Cell Theory 3 tenets (principles)
1.) All organisms consist of 1 or more cells
2.) The cell is the basic unit of structure for all organisms
3.) All cells arise from existing cells (Virchow, 1858)
(Omnis cellula e cellula = all cells from cells)
History: 3 main disciplines that contribute to our current understanding of cell biology/physiology::
- ) cytology
- ) biochemistry
- ) genetics
Cytology =
Using microscopy to visualize cells
Biochemistry =
analyzing the chemical components of cells
Genetics =
analyzing how various traits of cells and organisms are passed to subsequent generations
Cytology (2 main techniques):
- ) light microscopy (LM)
2. ) electron microscopy (EM)
LM allowed for
for the visualization of cells and sub-cellular structures
LM limitations?
Resolving power
(LM)
d =
= resolving power (nm) = lamdba/lens NA
(LM)
lens NA =
= numerical aperature of lens ≈ 2
(LM)
lambda light =
= 380 to 760
(LM)
On average, d ≈ ___ nm = __ mm
d ≈ 200 nm = 0.2 mm
LM can only…
…resolve objects that are 0.2 mm or more apart
EM is an increase in…
…resolving power by using electrons (e-) instead of light
(EM)
An accelerated e- has a lambda =
0.01 nm
Resolving power approaches __ nm for EM
vs ___ nm for LM
0.1 nm for EM
200 nm for LM
(EM)
allowed for…
…better visualization of sub-cellular and even molecular structures
Biochemical studies revealed important information about: (3)
- ) Metabolism (enzymes and pathways)
- ) Biochemical structures and functions
- ) Several technical procedures (Radioisotopes, Fractionation, Centrifugation, Chromatography, Electrophoresis)
Biochemical studies = ability to…
Ability to analyze or isolate individual components of a complex mixture
Genetic Studies (2)
- ) Classical (Mendelian) genetics
2. ) Molecular Biology
Classical (Mendelian) genetics =
= Observing inheritance of traits – allele frequencies
Molecular Biology =
= Modern Science focused on genetic material (DNA and RNA) and function
Scientific Method: (6)
- ) Make Observations
- ) Formulate a “testable” hypothesis
- ) Design experiment to test the hypothesis
- ) Perform experiment and collect data
- ) Interpret results
- ) Interpretation must support or refute the hypothesis (accept or reject hypothesis)
The scientific method is good but
Not all science is done this way!
Other scientific methods: (3)
- ) Discovery Science
- Eg., Astronomy & discovery of new stars… - ) Observational Science
- Initial studies on human & animal behavior - ) Incidental Observation
- Discovery of Goretex®, idea for Velcro®
(Cell Chemistry)
5 main principles (ideas):
- ) Importance of carbon
- ) Importance of H2O
- ) Importance of selectively permeable membranes
- ) Importance of synthesis by polymerization
- ) Importance of self assembly
organic chemistry =
= Study of carbon chemistry
Macromolecules in cells/organisms are
carbon-based
(Carbon)
What makes carbon important? (4)
- ) Valence of 4 (Missing 4 of 8 outer shell e-)
- ) Carbon-based molecules are stable
- ) Carbon-based molecules are diverse
- ) Some carbon-based molecules can form stereoisomers (mirror-images).
Since carbon have 4 valence electrons, it needs to…
this allows for…
this results in…
…share 4 electrons from other atoms (another C, H, O, N, S)
…the formation of 4 covalent bonds
…a high diversity of potential molecules
(Carbon molecules are stable)
Since H, O, N, and S are…
…among the lightest elements to form covalent bonds, the bonds they form with carbon are quite stable.
(Carbon molecules are stable)
Covalent Bond Strength proportional to
1/atomic mass of the two bound atoms
(Carbon molecules are diverse)
Carbon can form…
Carbon can bind…
…long chains & complex ring structures
…multiple side groups
(carbon-based molecules can form stereoisomers)
can result in…
…optical isomerism & greater diversity
Importances of H2O: (5)
- ) Abundance
- ) H2O is polar, despite being uncharged
- ) Water molecules are cohesive
- ) High temperature stabilizing capacity
- ) H2O is an excellent solvent
H2O abundance =
the single most abundant cellular molecule (75-85%)
( H2O is polar)
this makes water…
what can dissolve in water?
…“fluid”
- charged molecules
(H2O is cohesive)
allows for…
accounts for…
…hydrogen bonding
…surface tension and high boiling point (liquid state at most of earths surface)
(H2O high temp stable capacity)
water can…
which can…
…absorb thermal energy without changing phase
…keep cells from over-heating
(H2O as a good solvent)
Since most molecules in cells have some…
…polarity or charge, they readily dissolve in H2O.
Charged and polar =
Non-polar =
= hydrophilic
= hydrophobic
(Importance of selectively permeable membranes)
Cells are composed of…
…amphipathic phospholipids that form a bilayer
Amphipathic =
= has both hydrophilic (polar or charged) and hydrophobic portions (non-polar)
Amphipathic phospholipids can…
which =
…self assemble
= lipid bilayers/micelles
(Phospholipid)
head =
tail =
= hydrophilic
= hydrophobic
(Importance of selectively permeable membranes)
The cellular membranes act as…
Low MW molecules (below 100 atomic mass units (Da))
- if non-polar or polar…
- if charged…
Large MW molecules (above 100 Da)…
…barriers that regulate which substances can cross from one side to the other.
…they can rapidly diffuse across (O2, CO2, H2O, ethanol, urea)
…they cannot simply diffuse across (need some type of transport protein) (K+, Na+, Cl-)
…cannot directly cross the membrane and require some protein transporter
Synthesis by Polymerization =
Large number of macromolecules (polymers) formed from relatively few small organic molecules (monomers).
polymers =
monomers =
= macromolecules
= small organic molecules
3 main types of Macromolecules:
& examples
- ) Informational: Nucleic Acid, Proteins
- ) Structural: Proteins, Carbohydrates
- ) Storage: Proteins, Carbohydrates, Lipids
(Synthesis by Polymerization)
Requires…
Thus…
…energy (ATP) to synthesize macromolecules
…energy can be obtained from their degradation (lipids, carbohydrates, proteins)
(Self-Assembly)
allows for…
& examples
results in… (2)
…energy conservation
(ex: lipid bilayers, protein)
…polypeptide renaturation and protein folding
protein folding:
hierarchy, examples, consequences
1* structure (a.a. polypeptide chain)
induces folding into
2* structure (a-helix, or b-sheet)
induces further folding into
3* structure (overall folding of polypeptide chain)
induces further interaction
4* structure (multi-subunit interactions)
Molecular Chaperones =
& example
may assist in self-assembly process
ex: heat shock proteins
