Spirogyra are green algae that can reproduce sexually. Which of the following is true only of a sexually-reproducing organism such as Spirogyra?
a. The cells of parent algae have nuclei.
b. Each offspring contains chloroplasts.
c. Several offspring may be produced at once.
d. Genetic material is contributed by two parent cells.

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.

Which beat describes the brain stem

What kind of bond is created by the attraction between atomic particles of opposite charge? ionic bond hydrogen bond covalent bond nuclear bond