biology 3 test

What happens to the surface area to volume ratio as cells get larger? Why?
Click the card to flip 👆
1 / 10
Terms in this set (10)
What happens to the surface area to volume ratio as cells get larger? Why?
As cells get larger, the surface area to volume ratio gets smaller. This means there is less surface area per unit of volume.
A unicellular organism is discovered. It has DNA and ribosomes, but neither a mitochondria nor endoplasmic reticulum. Is the cell a prokaryote or a eukaryote? Explain how you know.
Prokaryotic. Cells that lack a nucleus and organelles such as mitochondria and endoplasmic reticula are prokaryotic.
List several differences between plant and animal cells.
Plant cells contain a cell wall made of cellulose, chloroplasts, which they use to carry out photosynthesis, and a large vacuole that they use to store materials. Animal cells lack these things.
Muscle cells have more mitochondria than some other kinds of eukaryotic cells. In what way would having many mitochondria be beneficial to muscle cells?
Muscle cells use ATP when they contract. Having many mitochondria would help provide the large amount of ATP needed for contraction.
The cells in your pancreas produce a protein called insulin. The pancreas cells release insulin into your bloodstream. The job of the insulin protein is to help regulate blood sugar levels. Describe how the pancreas cells are able to produce and release this protein. Start with the cell part that makes proteins in the cell.
Ribosomes in the cell make the insulin protein. Insulin is then transported through the endoplasmic reticulum. Insulin leaves the ER inside a vesicle, and it travels to the Golgi apparatus. The Golgi apparatus finishes and prepares the insulin protein by making any necessary modifications to the protein (such as helping it to finish folding or attaching any carbohydrates that help it perform its function). Then, the Golgi apparatus packages the protein inside another vesicle and sends it to the cell membrane. The insulin proteins are released from the cell into the bloodstream through the process of exocytosis. (See diagram on next page...)
What term describes the property of a cell membrane that allows only certain particles to pass through it? Since the cell membrane only allows certain types of ions and molecules through, how would this affect the ability of different types of molecules to reach equilibrium between the cell and the fluid around it?
Selective permeability (or "semipermeable"). Substances that are able to cross the membrane will reach equilibrium. Substances that are not able to cross the membrane will not and will have different concentrations inside and outside the cell.
Compare and contrast diffusion, osmosis, and facilitated diffusion.
All three are methods of passive transport, which means that they do not require energy and that materials move from a high concentration to a low concentration. They are different in that osmosis only involves the movement of water and that facilitated diffusion requires a membrane protein.
The pain of a sore throat is caused by the swelling of tissues with water. Use your understanding of osmosis to explain why gargling with salt water would help this pain.
Salt water has a greater concentration of dissolved particles than your swollen tissues. As a result, water will move from the swollen tissue into the salt water solution. Another way to think about it is that the swollen tissue has a higher concentration of water, so water moves from the tissue into the salt water. Gargling with salt water will make your throat cells shrink, which will reduce the swelling and help your pain.
How are active transport and facilitated diffusion similar? How are they different?
Both require the use of a membrane protein. However, active transport uses energy to move against the concentration gradient (from low→ high concentration). Facilitated diffusion does not use energy and therefore only allows substances to move down their concentration gradient (from high→ low concentration).
When a cell takes in a food particle by endocytosis, the vesicle that is formed may fuse with a lysosome. How would fusion with a lysosome help the cell digest the food particle?
Lysosomes contain digestive enzymes that can digest/break down food/macromolecules.