cells approximately 1.7 billion years ago. The structure of eukaryotic cells today
suggests how they might have evolved from their prokaryotic ancestors. Scientists
examining mitochondria and chloroplasts now think that these organelles were probably
free-living prokaryotes before becoming a part of eukaryotic cells long ago.
Which of the following is a characteristic of mitochondria that suggests that they might
have evolved from free-living bacteria?
A) Mitochondria have cell walls.
B) The plasma membrane of a mitochondrion, forming the surface of this organelle, is
the site of many important steps of cellular respiration.
C) Mitochondria have their own DNA.
D) Mitochondria rely upon proteins as their source of energy.
Please use the following information to answer the following questions.
You work for a company selling tropical rain forest plants commonly found in the
understory of the forest. These plants are shade tolerant and can be grown indoors
because they require low light. Your employer wants you to find out what is the best
type of light to maximize growth of these understory plants. Using a full spectrum of
natural light would cause these plants to die because they are a shade-tolerant plant
species.
From your biology class, you recall that the light-dependent reactions of photosynthesis
involve pigment molecules that absorb light of specific wavelengths. You also
remember the experiments done by the German biologist Theodor Engelmann, in which
he separated light using a prism into different wavelengths and then determined which
wavelengths were best for promoting photosynthesis in the algae species he was
examining. Your goal is to determine which wavelengths (colors) of light are best for
promoting photosynthesis to enhance growth in your species of plant. To achieve this,
you grew your plants under different wavelengths of light and measured their growth
rates. The wavelengths were measured in nanometers (nm), and the growth rate was
measured in millimeters per day (mm/day). The data you collected are as follows: