Test 2 Review Flashcards
Define “energy”
The capacity to do work (to cause change)
Compare potential and kinetic energy
Potential Energy: Stored Energy
Kinetic Energy: Energy associated with motion
The energy found in glucose is an example of _ energy
Potential
Explain why cell need energy?
All living systems require an ongoing supply of energy
Photoautotrophs are capable of converting _ carbon into _ carbon, which can then be used by both heterotrophs and autotrophs for growth/development
Inorganic, organic
Humans ultimately depend on autotrophs for the production of ….
Oxygen and Glucose
What is an autotroph?
An organism that produces organic compounds from inorganic molecules
What are heterotrophs?
An organisms that produces organic compounds starting from other organic molecules
What is a phototroph?
An organism able to capture light energy and transform it up to chemical energy
What are chemotrophs?
Organisms that obtain energy by oxidizing chemical bonds in molecules
True or False? Plants make energy from the sun.
False
Define “ thermodynamics”
The study of energy transformations
What is the first law of thermodynamics?
Energy can be transferred and transformed. Energy can not be created or destroyed.
What is the second law of thermodynamics?
Every energy transfer of transformation increases the entropy of the universe. During every energy transfer some energy is unusable.
Which term indicates the amount of energy released or required by a given system?
Delta G
Define free energy
The measure of thermodynamics spontaneity of a system. The amount of energy available to do work.
What does deltaG tell us about a system?
DeltaG tells us whether a process can occur(possibility) and to what extent (directionality)
What does it mean if deltaG is zero ?
This means the system has reached equilibrium.
Can work be done by a system in equilibrium?
No
The oxidation of glucose releases 686 kcal/mol. Is this a spontaneous process?
Yes
A larger EA means a rxn will occur_ compared to a rxn with a smaller EA.
Slower
Which processes (anabolic or catabolic) are associated with a -deltaG?
Catabolic
ATP breakdown is an _process while ATP synthesis is an _
Exergonic, endergonic
Where would opposing charges occur on ATP molecule?
Between adjacent phosphates
What will opposing charges do to the free energy of the ATP molecule?
Increase the free energy
The formation of a bond between phosphate and R will result in the molecule formed being _stable compared to the phosphate group alone.
Less
True or False? The formation of a bond between phosphate and R will result in the molecule formed having a lower amount of free energy compared to the free energy of the phosphate group alone.
False
Describe the activation energy barrier for a reaction. How does EA influence rage of a rxn?
EA is the amount of energy reactant must have in order for a rxn to take place. The amount of energy needed to reach the “transition state”
Rxn rate is determined by EA
Define metabolism
Total collection of chemical reactions that take place in a cell
Differentiate between catabolic and anabolic processes
Anabolism: synthesis pathways , endergonic
Catabolism: break down pathways, exergonic
What type of molecule is ATP?
Nucleotide
What is inorganic phosphate?
Free phosphate ion, not complexed with a largest organic molecule
Explain the role of ATP in a cell
Used to do work
An enzyme will _ chemical reactions and _ activation energy.
Speed up, lower
True of False? The amino acids forming the active site must be adjacent to each other in the primary structure of the enzyme.
False
Sucrose is _ to release it’s constituent monomers, glucose and fructose.
Catabolized
The catabolism of sucrose is ….
Exergonic
True or false? Enzymes speed up a reaction by altering deltaG.
False
Based on the pH optimum, pepsin is a digestive enzyme found in the _, whereas trypsin is localized to the _
Stomach, small intestine
Pepsin and trypsin are both proteolytic enzymes. This means that they….
Catabolize proteins
Pepsin and trypsin went through the _ pathway .
Cotranslational import
True of False? A non competitive inhibitor is a type of an allosteric regulator.
True
What are the six different classes of enzymes ?
Oxidoreductases, Hydrolases, Lyases, Isomerases, Ligases
Type of hydrolase, breaks down nucleic acids by hydrolyzing bonds between nucleotides
Nucleases
Type of hydrolase, breaks down proteins by hydrolyzing bonds between nucleic acids
Proteases
Type of ligase, synthesizes molecules in anabolic reactions by condensing 2 smaller molecules
Synthases
Type of transferase, catalyzes the addition of phosphate groups to protein targets
Phosphorylase
Type of hydrolase, catalyzes the hydrolytic removal of phosphate groups from target
Phosphotase
Important group of kinases that attach phosphate groups to protein targets
Protein Kinases
Type of hydrolase, hydrolyze ATP into ADP +P¡ (Exergonic reaction)
ATPases
Synthesizes ATP from ADP+P¡ (endergonic reaction)
ATP synthases
True or False? The Gram stain exploits differences in the thickness of the extracellular matrix.
True
The coding strand of a gene contains the following codon 5’-TGG-3’. If a point of mutation occurred in which thymine in the codon was converted to cytosine, what would result in corresponding mutant polypeptide sequence?
A] a nonpolar amino acid would be replaced by a basic amino acid
B] a polar uncharged amino acid would by replaced by a basic amino acid
C] a polar uncharged amino acid would be replaced by an acidic amino acid
D]a nonpolar amino acid would be replaced by a polar uncharged amino acid
A]
True or False? Sickle cell anemia results from a change of a non-polar amino acid in the wild-type protein into a negatively charged amino acid in the mutant protein.
False
Which has the greatest surface area to volume ratio?
A) Cell 1, with dimensions of 1um cubed
B) Cell 2, with dimensions if 5 um cubed
C) Cell 3, with dimensions of 0.125 um x 5 um x 200 um
D) Multicellular organism 1, comprised of 125 cells, each with same dimensions as Cell 1
C)
Mitochondria are thought to have evolved from ancestral bacteria. Which characteristics of a free-living bacterium have mitochondria lost over time?
A) circular genome
B) extracellular matrix
C) 70s ribosomes
D) division of binary fission
E) none of the above
B)
Phagocytosis of a bacterium by a white blood cell leads to the bacterium being engulfed inside a phagosome. The WBC will eventually degrade the bacterium. Which of the following events is associated with this overall process?
A) the phagosome will fuse to a peroxisome in order to breakdown the bacterium
B) the membrane of the phagosome is deceived from the cell wall of the bacterium
C) Digestion of the bacterium will occur by enzymes found directly in the cytoplasm of the WBC
D)the hydrolytic enzymes involved with the breakdown of the bacterium were synthesized by the co-translational import pathway
D)
Cytoskeletal elements can be found in the …..
A) cytoplasm
B) nucleus
C) extracellular space
D) all of the above
E) A and B
E
What is enzyme kinetics ?
Study of enzyme catalyzes reaction rate
Who where Leonor Michaelis and Maud Menten and why do we care about them?
1913, German scientist, developed a model to explain enzyme action