1. The stimulation of a motor neuron ultimately results in the release of a neur
ID: 265512 • Letter: 1
Question
1. The stimulation of a motor neuron ultimately results in the release of a neurotransmitter at the synapse between the neuron and a muscle cell. What type of neurotransmitter is used at these neuromuscular junctions? A) epinephrine B) dopamine C) acetylch muscarine endocannibidoids 2. The lab you work in has discovered a previously unidentified extracellular signal molecule called QGF, a large protein. You add purified QGF to different types of cells to determine its effect on these cells. When you add QGF to heart muscle cells, you observe an increase in cell contraction. When you add it to fibroblasts, they undergo cell division. When you add it to nerve cells, they die. Given these observations, which of the following statements i most likely to be true? Heart muscle cells, fibroblasts, and nerve cells must all have the same receptor for QGF B) Because it acts on so many diverse cell types, QGF probably diffuses across the plasma membrane into the cytoplasm of these cells Nerve cells do not have a receptor for QGF D) QGF activates different receptors and intracellular signaling pathways in heart muscle cells, fibroblasts and nerve cells. E) QCF is not a chemical messenger 3 A protein kinase can act as an integrating device in signaling if it A) initiates a phosphorylation cascade involving two or more protein kinases. B) is activated by two or more proteins in different signaling pathways C) phosphorylates more than one substrate D) catalyzes its own phosphorylation E) binds GTP 4. Which of the following statements about G-protein-coupled receptors (GPCRs) is false? A) GPCRs are used in endocrine, paracrine, and neuronal signaling. B) The different classes of GPCR ligands (proteins, amino acid derivatives, or fatty acids) bind to receptors with different numbers of transmembrane domains. GPCRs are the largest family of cell-surface receptors in humans. D) G PCRs are ion-channel coupled receptors. E) GPCRs alter important cell proteins 5. What is the role of calcium ions in the contraction of skeletal muscle? Calcium ions directly activate ATPase in the myosin head actin/myosin interaction. Calcium ions bind to lactic acid to remove it from the contracting muscle. A) m ions bind to the troponin-tropomyosin complex and remove their inhibitory action on C) Calcium ions diffuse across the synaptic cleft to result in depolarization of the muscle membrane. cium ions triggers the immediate regeneration of ATP to power the contraction.Explanation / Answer
1- C acetyl choline
2- A
3- C phosphorylates more than one substrate
4- B because there are same number of transmembrane domains
5- B
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.