Which of the following statements is not true about mrna?
a. prokaryotic mrna may contain multiple structural genes on the same transcript, known as polycistronic mrna.
b. eukaryotes only transcribe one gene at a time on mrna, called monocistronic mrna
c. some eukaryotes are capable of having polycistronic mrna
d. eukaryotes almost always produce polycistronic mrna
e. the genes for metabolic pathways in bacteria are typically located close together and transcribed on one mrna

The correct answer is d. eukaryotes almost always produce polycistronic mRNA

Explanation:

mRNA can be polycistronic or monocistronic. A monocistronic mRNA contains the information of one gene only so a monocistronic mRNA code only one protein at a time but a polycistronic mRNA can code for multiple proteins at a time.

In eukaryotes, one transcriptional unit carries the information of only one protein so eukaryotes produce monocistronic mRNA but some eukaryotes are capable of having polycistronic mRNA.

In prokaryotes, many genes are transcribed as a unit to produce multiple proteins so prokaryotes produce polycistronic mRNA. Therefore the statement which is not true is d. eukaryotes almost always produce polycistronic mRNA.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.