The earliest cells detectable in fossils were different from the cells in animals, plants, fungi, and protists living today. These first prokaryotic cells gave rise to eukaryotic 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 chloroplasts that suggests that they might have evolved from free-living bacteria?
A) Chloroplasts have cell walls.
B) Chloroplasts contain pigments.
C) Chloroplasts have their own DNA.
D) A single, highly folded plasma membrane surrounds chloroplasts.
Ans: C) Chloroplasts have their own DNA.
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What temperature is most commonly used for autoclaves to sterilize growth media and other devices prior to experimentation?
A) 95 °C B) 101 °C C) 121 °C D) 140 °C
Genes that are _________ do not assort independently and are said to be _____
A. distant from one another on the same chromosome; linked. B. close to one another on the same chromosome; linked. C. distant from one another on the same chromosomes; independent. D. close to one another on the same chromosome; independent. E. None of the answer options are correct.
Konrad Lorenz is noted for his studies on
a. prenatal marking. b. mating behavior. c. imprinting. d. the genetic basis of behavior. e. insight learning.
Parasitic relationships are typically loose associations between two species.
Answer the following statement true (T) or false (F)