Bio Chapter 5 Study Guide

Explain the reason why saltwater fish cannot survive in fresh water. Explain the reason why freshwater fish cannot survive in salt water.

It is based on how much salt their bodies can handle, which is why only some can live in fresh and others in salt.

Two molecules, A and B, and their distribution inside and outside of a cell are represented in the diagram below. Describe the reason why molecule A could diffuse across the membrane of the cell but molecule B could not. Write as many reasons as you can find.

Molecule A might be smaller than molecule B. The cell is going through simple or facilitated diffusion.

Give an example of how two or more organ systems may work together to maintain homeostasis.

The nervous and endocrine systems exert the ultimate control over homeostasis because they control the functions of the body's systems. Regulation of body temperature, blood pressure, pH, and glucose concentration are 4 example of how the body maintains homeostasis.

The diagram below shows a single-celled organism called Paramecium, which lives in freshwater environments. This organism contains a specialized organelle called contractile vacuole that pumps out excess water that may enter the cell. Predict how this organelle might help the organism maintain homeostasis given that it is constantly immersed in a hypotonic solution.

When water moves into the cell it can cause cytolysis, so the contractile vacuole gets rid of the water so that it does not burst.

Concentration gradient

a difference in the concentration of a substance across a distance

Protein channel

a protein that allows the transport of specific substances across a cell membrane

Receptor

a specialized sensory nerve that responds to specific types of stimuli

Semi-permeable

allowing certain things to pass through

Homeostasis

keeping the internal environment in a steady state (it is controlled by negative feedback mechanism)

Endocytosis

moving things in

Exocytosis

moving things out

Control center

sets the range of values to be maintained

Effector

something that causes an effect

Osmosis

the diffusion of water or another solvent from a more dilute solution (of a solute) to a more concentrated solution (of the solute) through a membrane that is permeable to the solvent

Negative feedback

the opposite reaction to a fall or rise above normal value

Phagocytosis

used to engulf large particles such as food, bacteria and other things into vesicles