enzyme
What is the role of an enzyme in a chemical reaction?
page 2
What are the two categories of metabolism, and how does catabolism drive anabolism? (Page 1)
Metabolism is divided into two categories: catabolism and anabolism. Catabolism involves breaking down molecules and releasing energy, which is used to make ATP. Anabolism, on the other hand, involves the synthesis of larger molecules from smaller ones and requires energy. Catabolism drives anabolism by providing the energy needed for building larger molecules, like proteins and fats, through the breakdown of energy-rich compounds such as glucose.
What is resting membrane potential (RMP), and what causes it?
dark current
Dark current refers to the steady depolarizing current in photoreceptors (rods and cones) that occurs in the absence of light. It is maintained by the constant influx of sodium (Na+) ions through open sodium channels in the photoreceptor membranes.
How does temperature affect enzyme activity?
what are other things that affect enzyme activity?
Enzyme activity increases as temperature rises up to an optimal point, because higher temperatures increase molecular motion, which facilitates enzyme-substrate collisions. However, if the temperature exceeds the optimal range, the enzyme's 3D structure can become denatured, reducing or completely stopping its activity.
Outline the main stages of glycolysis and the net production of ATP and NADH. (Pages 3–4)
Glycolysis is the process by which one molecule of glucose (C6H12O6) is broken down into two molecules of pyruvate (C3H4O3) in the cytoplasm. During glycolysis, 2 ATP molecules are used to "prime" the glucose molecule, but 4 ATP molecules are produced through substrate-level phosphorylation, resulting in a net gain of 2 ATP. Additionally, 2 NAD+ molecules are reduced to 2 NADH. The overall net production from glycolysis is 2 ATP and 2 NADH per glucose molecule
Describe the process of synaptic transmission at a chemical synapse.
Explain the process of sound wave transmission in the cochlea.
Sound waves enter the cochlea and create pressure waves in the perilymph fluid of the scala vestibuli. These waves travel through the cochlea, causing displacement of the basilar membrane, which bends hair cells and converts mechanical vibrations into electrical signals.
What is the significance of cofactors and coenzymes in enzyme function?
Describe the role of the electron transport chain (ETC) in cellular respiration and explain how ATP is generated through oxidative phosphorylation. (Pages 11–13)
The electron transport chain (ETC) is a series of protein complexes located in the inner mitochondrial membrane. NADH and FADH2, generated from glycolysis and the Krebs cycle, donate high-energy electrons to the ETC. These electrons are passed along the chain from one protein complex to another, and as this occurs, the energy released is used to pump protons (H+) into the mitochondrial intermembrane space, creating a proton gradient. This gradient drives protons back into the mitochondrial matrix through ATP synthase, a process called oxidative phosphorylation. The flow of protons through ATP synthase provides the energy to convert ADP into ATP. Oxygen acts as the final electron acceptor in the ETC, combining with electrons and protons to form water. This process can produce approximately 26–34 ATP molecules per glucose, depending on the efficiency of the system.
What is an action potential, and how does it propagate along an axon?
How do rods and cones function in the retina?
Explain how allosteric inhibition regulates enzyme activity in metabolic pathways.
Page: 8
Allosteric inhibition occurs when a product of a metabolic pathway binds to an enzyme at a site other than the active site, called the allosteric site. This binding induces a conformational change in the enzyme, rendering it inactive and preventing the further accumulation of the final product. This mechanism provides negative feedback and controls the flow of the metabolic pathway.
Explain the chemiosmotic theory in the context of ATP synthesis during oxidative phosphorylation. (Page 12)
Answer: The chemiosmotic theory explains how energy from the electron transport chain (ETC) is used to pump protons (H+) into the outer chamber of the mitochondria, creating a high concentration of H+ ions. As H+ ions diffuse back into the inner chamber through ATP synthase, the energy generated drives the synthesis of ATP. This process is known as oxidative phosphorylation, where oxygen acts as the final electron acceptor, combining with H+ to form water.
What are the differences between excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs)?
What is the role of the semicircular canals in the vestibular apparatus?
The semicircular canals provide information about rotational acceleration. They are oriented in three different planes and contain sensory hair cells located in the crista ampullaris. When the head rotates, the movement of endolymph within the canals causes the hair cells to bend, generating action potentials that convey information about the direction and speed of the rotation to the brain.
What role do enzymes play in metabolic pathways, and how does end-product inhibition help regulate these pathways?
Enzymes are essential in metabolic pathways, facilitating each step from the initial substrate through intermediates to the final product. These pathways often involve branched steps where multiple products can be formed. End-product inhibition is a form of negative feedback that helps regulate these pathways. When the final product accumulates beyond the cell's needs, it binds to the branch-point enzyme at a site other than the active site (allosteric site), altering the enzyme's shape and deactivating it. This prevents the overproduction of the final product and redirects the pathway toward alternative products.
the role of the Krebs cycle in the production of NADH and FADH2 and how they contribute to the electron transport chain. (Pages 9–11)
The Krebs cycle (citric acid cycle) starts when acetyl CoA combines with oxaloacetic acid to form citric acid. During this cycle, for each acetyl CoA, 3 NAD+ molecules are reduced to NADH, 1 FAD is reduced to FADH2, and 1 GTP molecule is produced, which is converted to ATP. Since the cycle runs twice for each glucose molecule, the overall products are 6 NADH, 2 FADH2, and 2 ATP. NADH and FADH2 carry high-energy electrons to the electron transport chain, where they are used to produce more ATP through oxidative phosphorylation.
explain what happens when a AP reaches the end of an axon terminal.
Action Potential Arrival:
Ca2+ Influx:
Neurotransmitter Release:
What are the different types of sensory receptors and their functions?
Sensory receptors are categorized based on the type of stimulus they transduce: