In both photosystem I and photosystem II, light energy is used to excite electrons. To the confusion of many students, the two photosystems were named in the order of their discovery, and not in the order of their work in the light-dependent reactions. Photosystem II comes first in the sequence of events that moves electrons from water molecules to their destination, NADP+. Hydrogen ions travel with the electrons, and they change NADP+ into NADPH. The process is summarized in this diagram. The diagram shows rays of light striking Photosystem II and Photosystem I. An arrow leads from the splitting of water to Photosystem II , to Photosystem I, and then to the reaction that converts NADP+ to NADPH. Hydrogen ions move across the membrane. How is the production of NADPH useful for the process of photosynthesis

Mouse liver cells were homogenized and the homogenate subjected to equilibrium density-gradient centrifugation with sucrose gradients. fractions obtained from these gradients were assayed for marker molecules (i. e., molecules that are limited to specific organelles). the results of these assays are shown in the figure. the marker molecules have the following functions: cytochrome oxidase is an enzyme involved in the process by which atp is formed in the complete aerobic degradation of glucose or fatty acids; ribosomal rna forms part of the protein-synthesizing ribosomes; catalase catalyzes decomposition of hydrogen peroxide; acid phosphatase hydrolysis monophosphoric esters at acid ph; cytidylyltransferase is involved in phospholipid biosynthesis; and amino acid permease aids in transport of amino acids across membranes. a) name the marker molecule and give the number of the fraction that is most enriched for each of the following cell components: lysosomes; peroxisomes; mitochondria; plasma membrane; rough endoplasmic reticulum; smooth endoplasmic reticulum.

In which layer do organisms on earth love?

One function of the poly-a tail on eukaryotic mrna sequences is to the mrna be transported from the nucleus to the cytoplasm. prokaryotic mrna also has a poly-a tail. choose the best explanation of the prokaryotic poly-a tail. a. prokaryotic poly-a tails are composed of a different molecular structure compared with eukaryotic poly-a tails. b. prokaryotic poly-a tails have the same functions as eukaryotic poly-a tails, because this process is highly conserved throughout different species. c. prokaryotic poly-a tails aren't important, because prokaryotes don't have nuclei. d. prokaryotic poly-a tails have other functions, because prokaryotes don't have nuclei.