Term
| What is a Viroid, and describe it? |
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Definition
Small circular naked ssRNAs
No protein component
~250 – 450 nucleotides
Base pairs with self |
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Term
| Where can a viroid be found? |
|
Definition
Found in plants
Can cross cell walls and membranes
Use mRNA transcription machinery to make copies of self |
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Term
| What are Prions and describe them |
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Definition
‘Infectious’ proteins
Misfolded versions of normal protein
No genetic material
Very stable
Can’t be destroyed by normal sterilization |
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Term
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Definition
scrapie
PrPc – normal protein
PrPSc – scrapie protein |
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Term
| What is Prior Propagation? |
|
Definition
Prion protein induces normal protein to
misfold into more prion protein
Autocatalytic
Misfolded proteins aggregate and interfere
with normal neuronal cell function
Cells die leaving brain looking like a sponge |
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Term
|
Definition
Prion protein induces normal protein to
misfold into more prion protein
Autocatalytic
Misfolded proteins aggregate and interfere
with normal neuronal cell function
Cells die leaving brain looking like a sponge |
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Term
|
Definition
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Term
|
Definition
Sum of all of the chemical reactions
that take place within a cell |
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Term
| What does Metabolism involve? |
|
Definition
Involve pathways of sequential
enzymatic reactions (metabolic
pathways) |
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Term
| What are the two types of Metabolic pathways? |
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Definition
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Term
| What is a Catabolic pathway? |
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Definition
| Release energy by breaking down complex molecules |
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Term
| What is an Anabolic pathway? |
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Definition
| Consume energy to build complex molecules |
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Term
|
Definition
| ◦ Capacity to cause change |
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Term
|
Definition
Energy of motion
Thermal energy (heat |
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Term
| What is potential energy? |
|
Definition
Stored energy
Chemical energy (within structure)
Membrane potential |
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Term
| What is the First Law of Thermodynamics? |
|
Definition
◦ Conservation of Energy
◦ Energy cannot be created nor destroyed
It is converted from one form to another
Quantity of energy unchanged |
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Term
| What is the Second Law of Thermodynamics? |
|
Definition
◦ Entropy
◦ Overall disorder will always increase in closed systems
Some energy converted into heat
Always loss of ‘usable’ energy
Average ‘quality’ is always reduced |
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Term
| What is apparent contradiction? |
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Definition
| Life is inherently ordered |
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Term
| Describe why an organism is not a closed system |
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Definition
◦ Energy and materials are exchanged with
surroundings
◦ One specific aspect of disorder (entropy) can
decrease if the overall disorder increases |
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Term
|
Definition
◦ Portion of system’s energy available to do work
G (Gibbs’ Free Energy)
ΔG – change in Free Energy
ΔG = Gfinal – Ginitial
◦ Spontaneous processes have a negative ΔG (<0)
(energetically favorable, not instantaneous - may still
take a very long time)
ΔG = ΔH – TΔS
ΔH – Total Energy (Enthalpy)
ΔS – Disorder (Entropy)
T – Temperature (heat) |
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Term
| If a process is spontaneous, what does that mean? |
|
Definition
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Term
| What is an exergonic reaction? |
|
Definition
energy given off
- ΔG – spontaneous,
releasing energy |
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Term
| What is an Endergonic reaction? |
|
Definition
energy taken in
+ ΔG – non-spontaneous,
requires energy |
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Term
|
Definition
In closed systems, ΔG will be
negative until all potential
usable energy is exhausted,
then nothing more can
happen
ΔG ≯ 0
ΔG = 0 ⇒ dead
◦ Organisms are open systems
– receive energy from
surroundings
Equilibrium never reached |
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Term
|
Definition
Adenosine Triphosphate
◦ Adenosine with three phosphate groups
Adenine base
Ribose sugar (as found in RNA)
Three phosphate groups linked by high-energy
bonds |
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Term
|
Definition
◦ Energy carrier molecule
◦ Created with the energy from exergonic reactions
◦ Hydrolyzed to carry out endergonic
reactions |
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Term
|
Definition
◦ ‘Phosphorylate’ (add a phosphate group to) molecules
Phosphorylated compound has higher free energy (but
lower than what was stored in ATP – entropy)
◦ Remove phosphate to release energy |
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Term
|
Definition
| ATP phosphorylates transport proteins |
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Term
|
Definition
ATP binds noncovalently to motor
proteins and then is hydrolyzed. |
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Term
|
Definition
| ◦ ATP is continually being made and used |
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Term
|
Definition
Energy comes in from catabolism (exergonic,energy-releasing processes)
goes to ATP and H20 then it can go out as Energy for cellular work (endergonic, energy-consuming processes)
If energy does not release as cellular work then it turns into ADP and Pi then starts all over. |
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Term
|
Definition
◦ Biological macromolecules that act as catalysts to speed
up reactions
usually protein, sometimes RNA
◦ Not consumed by reaction
◦ Substrate specificity |
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Term
| What is Enzyme specificity? |
|
Definition
◦ Unique protein shape
Specific ionic, polar and hydrophobic interactions
between substrate and protein
Isomer-specific
◦ Substrate binds active site
‘lock & key”
induced fit |
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Term
| What is activation energy? |
|
Definition
◦ Energy required to initiate reaction
◦ Bring reactants to transition state
◦ Lowered by enzymes |
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Term
| What lowers activation energy? |
|
Definition
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Term
| How do enzymes lower activation energy? |
|
Definition
Lowering activation energy
◦ Provide proper environment
◦ Increase local concentration of reactants
◦ Stress bonds
◦ Participate directly in reaction |
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Term
| What does lowering activation energy do? |
|
Definition
Lowering activation energy
◦ Provide proper environment
◦ Increase local concentration of reactants
◦ Stress bonds
◦ Participate directly in reaction |
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Term
| Describe the catalytic cycle |
|
Definition
Substrates enter active site
Substrates are held in active site by weak interactions.
Active site can lower EA and speed up a reaction.
Substrates are converted to products.
Products are released
Active site is available for two new substrate molecules |
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Term
| What are factors that affect enzyme activity |
|
Definition
◦ Affecting structure
Temperature
pH
◦ Cofactors
Assist enzymes in reactions
called ‘coenzymes’ if organic
50% of enzymes require
cofactors
Metal ions
Vitamins
Nucleotide derivatives |
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Term
| What is energy of lowest quality and why? |
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Definition
| ◦ Heat is energy of the lowest quality, most disordered |
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