bio ch. 3 quiz

According to the cell theory, what is required for an object to be considered alive?

All organisms are made of cells. All existing cells are produced by other living cells. The cell is the most basic unit of life

what are the similarities and differences between the cell wall and cell membrane

In plants, algae, fungi, and most bacteria, the cell membrane is surrounded by a strong cell wall, which is a rigid layer that gives protection, support, and shape to the cell. The cell membrane, or the plasma membrane, forms a boundary between a cell and the outside environment and controls the passage of materials into and out of a cell.

If vesicles are almost constantly pinching off from the ER to carry proteins to the Golgi apparatus, why does the ER not shrink and finally disappear?

It is constantly making lipids of which it is made

How do the cytoskeleton and the cytoplasm contribute to a cell's shape?

Microtubules are a fiber that make up the cytoskeleton an give the cell its shape. A cell is filled with cytoplasm, a jellylike substance that contains dissolved molecular building blocks—such as proteins, nucleic acids, minerals, and ions.

Explain what mitochondria do and why evidence suggests that they might have descended from free-living prokaryotes in the evolutionary past

Mitochondria supply energy to the cell.Unlike most organelles, mitochondria have their own ribosomes and DNA.

Cells are surrounded by a watery fluid, and they contain watery cytoplasm. Explain how the structure of the lipid bilayer is related to these two watery environments

The heads of the phospholipids are attracted to the water on the inside and outside of the cell

You know that many organelles are involved in protein production. Briefly explain where proteins are made, modified, and packaged within a cell.

As a protein is being made on these ribosomes in the rough ER, it enters the lumen. Inside the lumen, the protein may be modified by having sugar chains added to it, which can help the protein fold or give it stability

If you were looking through a microscope at an unknown cell, how might you determine whether it was a plant cell or an animal cell?

Only plant cells have chloroplasts, central vacuoles, and cell walls. Only animal cells have centrioles and lysosomes.

what are the similarities and differences between eukaryotic and prokaryotic

Prokaryotic cells do not have a nucleus or other membrane-bound organelles. Instead, the cell's DNA is suspended in the cytoplasm. Most prokaryotes are microscopic single-celled organisms. Eukaryotic cells have a nucleus and other membrane- bound organelles. The nucleus, the largest organelle, encloses the genetic information. Eukaryotes may be multi- cellular or single-celled organisms.

You know that both vesicles and vacuoles are hollow compartments used for storage. How do they differ in function?

Vesicles are used for transportation