The plasma membrane acts as a barrier in cells of all types to control the movement of substances into and out of the cell. a. explain how the plasma membrane acts as a semi-permeable barrier to various types of molecules based on its molecular structure. b. describe, in detail, three ways in which large molecules such as proteins can cross the plasma membrane.

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen

Indicate the coat color and the proportion of offspring with that color for each of the following crosses of rabbits. assume all are homozygous. agouti x albino a) 1/2 albino, 1/2 agouti b) all agouti c) 3/4 agouti, 1/4 albino

Asolution of an enzyme and a substrate was placed in a water bath and the temperature of the reaction was raised gradually. the graph shown was plotted at the end of the experiment. what can be concluded from the graph? a) temperature has no effect on the activity of the enzyme. b) the effect of temperature on the enzyme is unpredictable. c) the enzyme shows increased activity up to a certain temperature. d) the activity of the enzyme is inversely proportional to the temperature.