Unit 1
What are the main structural components of an amino acid?
Amino group, carboxyl group, H atom, alpha C, and R group
Cellular respiration is...
The process of converting food into energy
By what mechanism did chloroplasts and mitochondria evolve?
Symbiosis with prokaryotic cells
Define Apoptosis
Programmed cell death
How is oxygen generated by photosynthesis?
From the splitting of water molecules
What types of structures are present in primary, secondary, tertiary, and quaternary organizational levels?
In order... amino acid chains, alpha helix, beta pleated sheets & polypeptide chains, and assembled subunit
Describe the three stages of food breakdown. What happens and where does it take place? What is this breakdown of complex molecules called?
Digestion, glycolysis, and respiration; they occur in the cytoplasm and mitochondria; catabolism
What are signal sequences or sorting signals and how long are they?
A sequence of amino acids that directs proteins to a specific location; typically 15-60 amino acids long
Define Necrosis
Sudden cell death; messy, and unplanned
What is the coat on a coated vesicle and what are its two functions?
Clathrin; helps in vesicle formation and directs transport
Compare cooperativity and allosteric regulation.
Cooperativity: Where the binding of one substrate molecule affects the binding affinity of additional substrate molecules
Allosteric: involves the binding of molecules at sites other than the active site
What enzyme complex is used to convert pyruvate? What are the products of pyruvate decarboxylation?
Pyruvate dehydrogenase; acetyl CoA, CO2, and NADH
Are proteins folded or unfolded as they enter mitochondria or chloroplasts?
Proteins enter unfolded
What allows the same signaling molecule to cause different responses in different cell types?
The different signaling pathways and intracellular molecules present in the cells.
What family of proteases regulates apoptosis? How are the inactive molecules activated?
Caspases; they are activated by cleavage in response to apoptotic signals.
Describe the structure and components of the plasma membrane?
Phospholipid bilayer is composed of two layers of phospholipids with hydrophobic tails facing inward and hydrophilic heads facing outward, proteins are embedded or attached to the bilayer and are involved in transport, signaling, and structural support, carbohydrates are attached to proteins or lipids, and involved in cell recognition and signaling, cholesterol is within the bilayer, affecting membrane fluidity
What is meant by chemiosmotic coupling?
The coupling of electron transport to ATP synthesis through a proton gradient
What is exocytosis? Endocytosis?
Exocytosis is the release of materials; endocytosis is the intake of materials
What is the fast response to a molecular signal? What is the slow response to a molecular signal?
Fast: changes in protein activity; Slow: changes in gene expression.
What are the three configurations of the voltage-gated Na+ channel, how do they work and why are they important?
Open: Allows Na+ ions to flow through the channel.
Inactivated: Prevents Na+ ions from passing through, shutting down the channel after opening.
Closed: The channel is not open but is capable of opening in response to a depolarizing stimulus. They are important because they ensure action potential travels in one direction so neurons ca return to resting state
What is an excitatory synapse? An inhibitory synapse? Give one example of each.
Excitatory Synapse: Promotes the generation of an action potential in the postsynaptic neuron (ex. glutamate)
Inhibitory Synapse: Prevents the generation of an action potential in the postsynaptic neuron (ex. A neuronal synapse that uses GABA as its transmitter)
What is the pathway the excited electrons take through photosystem II? What is the pathway the excited electrons take through photosystem I?
From chlorophyll to plastoquinone in photosystem II and to ferredoxin in photosystem I
What does it mean that Rab proteins are GTPases
They hydrolyze GTP to GDP for vesicle docking and fusion
M-Cdk drives entry into M phase and mitosis. What is the role of Cdc25 and the positive feedback loop it establishes in promoting M phase?
Cdc25 activates M-Cdk by dephosphorylation, and positive feedback amplifies this activation.
What family of proteins regulate the intrinsic apoptotic death pathway? Describe the intrinsic apoptotic pathway.
Bcl-2 family; the intrinsic pathway involves mitochondrial release of cytochrome c and activation of caspases.