【单选题】下列对非金属元素(除稀有气体元素外)的相关判断正确的是( ) ①非金属元素都是主族元素 ②单质在反应中都只能作氧化剂 ③氢化物常温下都是气态,所以都叫气态氢化物 ④氧化物常温下都可以与水反应生成酸 ⑤非金属元素R所形成的含氧酸盐(M a RO b )中的R元素必定呈现正价 ⑥氧化物都能与碱反应生成盐和水.
【单选题】唐代草书家 《肚痛帖》真迹不传,仅30 字,写来洋洋洒洒一气贯之。
【单选题】IP3 (inositol triphosphate) acts by ( ).
B.
phosphorylating signal receptors
C.
opening Ca 2+ channels
【单选题】Inositol triphosphate-gated calcium channels are located in
B.
the smooth endoplasmic reticulum
C.
the inner mitochondrial membraner
D.
regulated exocytotic vesicles.
【单选题】下列对非金属元素(稀有气体除外)的相关判断正确的是 [ ] ①非金属元素都是主族元素 ②单质在反应中都只能作氧化剂 ③氢化物常温下都是气态 ④氧化物常温下都可以与水反应生成酸 ⑤非金属元素R所形成的含氧酸盐(MaROb)中的R元素(除氟外)必定呈现正价
【单选题】下列对非金属元素(除稀有气体外)的相关判断正确的是 [ ] ①非金属元素都是主族元素 ②单质在反应中都只能作氧化剂 ③氢化物常温下都是气态,所以都叫气态氢化物 ④氧化物常温下都可以与水反应生成酸 ⑤非金属元素R所形成的含氧酸盐(MaRO b )中的R元素必定呈现正价
【单选题】下列对非金属元素(除稀有气体元素外)的相关判断正确的是 ( ) ①非金属元素都是主族元素 ②单质在反应中都只能作氧化剂 ③氢化物常温下都是气态,所以都叫气态氢化物 ④氧化物常温下都可以与水反应生成酸 ⑤非金属元素R所形成的含氧酸盐(M a RO b )中的R元素必定呈现正价
【多选题】How does the inositol phospholipid pathway trigger a rise in intracellular Ca 2+ ?
A.
Some GPCRs exert their effects through a G protein called G q , which activates the membrane-bound enzyme phospholipase C. Once activated, phospholipase C propagates the signal by cleaving a lipid molecule that is a component of the plasma membrane. The molecule is an inositol phospholipid that is present in small quantities in the cytosolic leaflet of the membrane lipid bilayer.
B.
Because of the involvement of this phospholipid, the signaling pathway that begins with the activation of phospholipase C is often referred to as the inositol phospholipid pathway. It operates in almost all eukaryotic cells and regulates a large number of different effector proteins.
C.
The cleavage of a membrane inositol phospholipid by phospholipase C generates two second messenger molecules: inositol 1,4,5-trisphosphate (IP 3 ) and diacylglycerol (DAG). Both molecules play a crucial part in relaying the signal. IP 3 is a water-soluble sugar phosphate that is released into the cytosol; there it binds to and opens Ca 2+ channels that are embedded in the ER membrane. Ca 2+ stored inside the ER rushes out into the cytosol through these open channels, causing a sharp rise in the cytosolic concentration of free Ca 2+ , which is normally kept very low. This Ca 2+ in turn signals to other proteins.
D.
Diacylglycerol is a lipid that remains embedded in the plasma membrane after it is produced by phospholipase C; there, it helps recruit and activate a protein kinase, which translocates from the cytosol to the plasma membrane. This enzyme is called protein kinase C (PKC) because it also needs to bind Ca 2+ to become active. Once activated, PKC phosphorylates a set of intracellular proteins that varies depending on the cell type.
【单选题】IP3 (inositol triphosphate) is produced from ( ).
【单选题】下列对非金属元素(除稀有气体外)的相关判断正确的是 [ ] ①非金属元素都是主族元素 ②单质在反应中都只能作氧化剂 ③氢化物常温下都是气态 ④氧化物常温下都可以与水反应生成酸 ⑤非金属元素R所形成的含氧酸盐(MaRO b )中的R元素必定呈现正价