List two differences observed between plant and animal cells.

List two differences observed between plant and animal cells.

Plant Cells have a Central Vacuole, Cell Wall, and Chloroplast. Animal Cells do not. Animal Cells have a Lysosome Flagellum, and Plant Cells do not.

Describe the function of the following? (3 points) a. cell membrane b. nucleus c. flagella d. mitochondria e. chloroplasts f. ribosomes

a. cell membrane- Encloses all cells and is primarily responsible for separating the internal environment from the extracellular space. b. Nucleus- Contains genetic information and is the central control center of the cell. c. Flagella- These structures extend beyond the cell membrane and cell wall and are used for locomotion. d. Mitochondria- The powerhouse of the cell because it is the site of energy production. e. Chloroplasts- Contains pigment and are responsible for creating food through photosynthesis. f. Ribosomes- Where the cells proteins are made.

Distinguish between an osmoconformer and an osmoregulator.

An osmoconformer is a marine organism that does not actively maintain salt and water balance at all; their internal concentrations change as the salinity of the water changes. Osmoregulator’s Control their internal concentrations to avoid osmotic problems.

List two ways that osmoregulators maintain the balance between their internal salt and water concentrations.

Freshwater fish have kidneys that excrete water fast. Then they reabsorb salt from their urine before it is ejected. They also take salt from their environment using special cells in their gills.

If a freshwater cell were placed in saltwater, would that cell increase in size, decrease in size, or stay the same? Explain the reasoning.

The cell would decrease in size. Osmosis would take the water out of the cell.

If a marine cell was placed in freshwater, would that cell increase in size, decrease in size, or stay the same? Explain the reasoning.

The saltwater cell would increase. Water is hypotonic and water would go into the cell from osmosis.

If the salinity of a body of water is 36.ppt, how many grams of salt are there for every 1,000 grams of water?

for every 1000 grams of water there would be 36 grams of salt

a. Did the volume of the potato cores placed in the distilled water increase, decrease, or stay the same? b. How did the results for the distilled water compare to the original hypothesis for this 0% solute environment? (2 points) c. Using the appropriate terms (hypotonic, isotonic, hypertonic) describe the movement of water molecules in this 0% solute environment. (2 points)

a. Increased slightly. (Not much light). b. Null hypothesis was proven incorrect. I thought that it would increase significantly. However I believe there wasn’t enough light or time. c. This would be an example of hypotonic. There was increase then it is an example of hypotonic, it gained size because of the larger concentration of water on the outside.

Did the volume of the potato cores placed in the 7% solution increase, decrease, or stay the same? (1 point) b. How did the results for the distilled water compare to the original hypothesis for this 7% solute environment? (2 points) c. Using the appropriate terms (hypotonic, isotonic, hypertonic) describe the movement of water molecules in this 7% solute environment. (2 points)

a. Decreased b. Null hypothesis was proven correct. c. The movement of the water molecules would be that of hypertonic. The solute is an increased amount of salt and the water molecules are leaving.

Predict how a marine osmoconformer would likely survive a change in salinity from 3.5% to 4.5%. (4 points)

Osmoconformers let the salinity in their fluids and their concentrations change as salinity of water changes. So going from 3.5% to 4.5% they would adapt eventually.

While sitting at the front of the classroom, someone walks in while wearing strong perfume. Within seconds, the smell is noticed by other students in front of the room. A student sends a text message to a friend in the back of the classroom who claims he cannot smell the perfume. Explain why the smell will eventually reach him. Given enough time, what will eventually happen to the perfume molecules? (4 points)

The process in which the perfume molecules will move from one area to another is considered diffusion. The perfume molecules in this case will move from an area of high concentration, which is the person wearing the perfume. To areas of low concentration, or where you friend is at. The molecules are in an area of low concentration to the friend who can’t smell it, and they will eventually move their way down that way once they move from the area of high concentration.

While watching a special on animals, a student discovers that hares tend to lose heat through their ears. Based on this and what is known about surface-to-volume ratios, propose an explanation as to why hares that live in hot climates (such as the desert) have large, extended ears. (4 points)

Since the ears are larger for the hare in a desert climate, this gives a bigger surface-to-volume area and lets the heat escape easier. 14. a. Calculate the surface-to-volume ratio of the following cubes: Cube 1: length, width, and height: 5 mm Cube 2: length, width, and height: 3 mm What were the surface-to-volume ratios for Cubes 1 and 2? (2 points) b. Which cube would be more efficient as a cell? (1 point)

Cube 1: 150/125 = 1.2 mm2/mm3 Cube 2: 54/27 = 2 mm2/mm3 Cube 2 would be more efficient as a cell because it has a larger SA/V ratio.