Chapter 1 Practice Problems Flashcards
Which one of the processes listed below is NOT thought to contribute to the evolution of new genes?
A.) Duplication of genes to create extra copies
B.) Horizontal transfer of DNA between cells of different species
C.) Mutation of existing genes to create new functions
D.) Formation of genes de novo from noncoding DNA in the genome
E.) Shuffling of domains of genes by gene rearrangement
D.) Formation of genes de novo from noncoding DNA in the genome
There are six genes that code for a protein called actin in the genome of most mammalian species. In humans, the ACTB gene is expressed ubiquitously, while ACTC1 is expressed mainly in cardiac cells. Although bacteria do not have actin, the bacterial MreB gene bears recognizable sequence similarity to mammalian actin genes and codes for a protein that is similar to actin in structure and function.
Which of the following statements is true about these genes?
A.) ACTB is homologous to ACTC1 but not to MreB.
B.) ACTB is orthologous to ACTC1 but not to MreB.
C.) ACTB is paralogous to ACTC1 but not to MreB.
D.) MreB is orthologous to ACTB but not to ACTC1.
E.) ACTB is paralogous to both ACTC1 and MreB.
C.) ACTB is paralogous to ACTC1 but not to MreB.
Which of the following is NOT true regarding the tree of life?
A.) Eukaryotes are more similar to archaea than to bacteria with respect to the proteins that act on their DNA.
B.) Most bacteria and archaea have genome sizes between 0.5 and 10 million base pairs
C.) Archaeal species were thought to belong to the eukaryotic world before sequence analysis placed them in a separate domain of life.
D.) Photosynthetic bacteria are thought to be the ancestors of the eukaryotic chloroplasts
C.) Archaeal species were thought to belong to the eukaryotic world before sequence analysis placed them in a separate domain of life.
Mitochondria and chloroplasts are thought to have evolved from free-living aerobic bacteria that were engulfed by an ancestral anaerobic cell and established a mutually beneficial (symbiotic) relationship with it. Which of the following statements is NOT true about these organelles?
A.) They are similar in size to small bacteria.
B.) They have their own circular genomic DNA.
C.) They have their own ribosomes.
D.) They have their own cell wall.
E.) They have double membranes.
D.) They have their own cell wall.
Biologists cannot possibly study all living species. Instead, they try to understand cell behavior by studying a select subset of them. Which of the following would NOT be considered an ideal trait of a model organism?
A.) relatively small size
B.) has a genome that has been sequenced
C.) large enough to be able to weigh on a scale
D.) can generate a sizeable offspring population
C.) large enough to be able to weigh on a scale
