Which statement is one of the tenets of cell theory?

• All cells take in energy and matter from the environment.

• Cells are separated from their environment by a cell membrane.

• All cells come from preexisting cells.

• All cells contain mitochondria.

• Cells sustain the living state through chemical transformations.

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NGSS.MS-LS1-1

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A researcher growing cells in culture observed that the cells always divided once they reached a certain size, regardless of her adjustments to nutrients and temperature in the growth chamber. What could explain these observations?

• Increasing cell size is accompanied by increasing cellular reactions, which produce more heat that threatens cell survival.

• Efficiency of transport of materials within a cell decreases with size, limiting the maximum cell size.

• The cell’s surface area increases faster than its volume as it increases in size, leading to an inability of the cell to feed itself.

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A general function of all cellular membranes is to

• regulate which materials can enter or leave the cell.

• support the cell and determine its shape.

• produce energy for the cell.

• produce proteins for the cell.

• move the cell.

The cytosol and _______ are two components of the cytoplasm in a prokaryotic cell.

• Golgi apparatus

• chloroplasts

• mitochondria

• ribosomes

• smooth ER

If you removed the pili from a bacterial cell, the bacterium would

• no longer be able to swim.

• lose some of its ability to adhere to other cells.

• no longer be able to regulate the movement of molecules into and out of the cell.

• dry out.

• change its shape.

Scientists have observed that in prokaryotes, translation of messenger RNAs begins before transcription has completed. In contrast, translation is completely separate from transcription in eukaryotes because DNA is isolated in the nucleus away from ribosomes, which carry out protein synthesis in the cytoplasm. What advantage does this compartmentalization provide eukaryotes?

• It eliminates the need for gene regulation.

• It makes protein synthesis more efficient.

• It provides a means for speeding up gene expression.

• It allows more opportunities for regulating gene expression.

A vesicle carries a protein to the cell membrane, where it is inserted into the phospholipid bilayer. The vesicle budded off from which subcellular structure before making the trip through the cytoplasm to the cell membrane?

• cis-Golgi

• Rough ER

• medial-Golgi

• Smooth ER

• trans-Golgi