Biology Trivia Answers: Cell Bits

Answers

Yesterday, I posted the following five statements and asked you to pick out the false one:

1. Aquaporins: A channel protein has been discovered in cell membranes that has been named aquaporin. As you might have guessed, these channels are basically pores that allow water molecules to be more easily transported through the membrane. 
2. Endoplasmic Reticulum:  This organelle, also called ER, usually comes in two different types: rough and smooth, with the rough having ribosomes attached. However, bacterial ER only comes in the smooth type as the bacterial ribosomes are unable to attach to the membrane surface.
3. Actin and Myosin: The motor protein actin and the cytoskeletal filament myosin form bundles in your muscle cells. Using energy from ATP, actin moves along the myosin to cause the muscle to contract. 
4. Mitochondria: Those amazing organelles known as the mitochondria have their own DNA which is inherited completely differently from the DNA in the nucleus. Whereas nuclear DNA comes from both parents, the nature of egg and sperm mean that mitochondria DNA is only passed from mother to offspring.
5. Lysosomes: Normally acting to break down molecules in the cell, lysosomes are capable of killing the cell if they break open.

So what's the correct answer?

2. Endoplasmic Reticulum: This statement is false! Bacteria, being prokaryotic, has no membrane-bound organelles. Most people only remember prokaryotes as having no nucleus, but the differences between prokaryotes and eukaryotes are more fundamental. The only organelles that bacterial cells do have are ribosomes. It is true that the bacterial ribosomes are different from eukaryotic ribosomes, but the differences have nothing to do with the ability to attach to ER.