Exam 1: Cells and Genomes

Imagine two spherical cells, one of which is 5000 times larger in volume than the other. The smaller is a prokaryote, and the larger cell is a eukaryote with 20% of its volume confined in a spherical nucleus. If the diameter of the prokaryotic cell is 0.7 micrometers, what is the diameter of the nucleus in the eukaryotic cell in micrometers? Write down your answer as a number only.

This model organism is particularly well suited for studying developmental processes in higher animals. It develops from a fertilized egg to an adult in only two to three months, and its body is transparent for the first two weeks, making it easy to observe cell behavior during development. Which of the following describes this organism?

What is the order of the following evolutionary landmarks (A to D), from the oldest to the most recent? Your answer would be a four-letter string composed of letters A to D, with the oldest event on the left. A. Divergence of human and bird lineages B. Divergence of human and chimpanzee lineages C. Divergence of A. thaliana lineage from the conifers lineage D. Divergence of fish and insect lineages

Didinium nasutum is a single-celled eukaryote that can hunt and feed on other living cells. It has an elaborate anatomy with beating cilia, a "mouth opening," an "anal aperture," and a set of contractile bundles; it can also shoot "darts" to paralyze its prey. What group of living cells does D. nasutum represent?

In terms of cellular lifestyle, different kingdoms of life can be likened to hunters, farmers, and scavengers. Which of the following is true in this scheme?

Which of the following structures is exclusively found in eukaryotic cells?

It is a model organism used to study various cell and developmental processes such as the growth of developing body parts in the right place and with the correct shape. It develops from a fertilized egg to an adult in a little over a week, and has been a favorite of geneticists for almost a century. Some of its cells have giant chromosomes whose banding patterns have been extremely helpful in classical genetic studies. Which of the following describes this organism?

Imagine a segment of DNA (within a gene) encoding a certain amount of information in its nucleotide sequence. When this segment is fully transcribed into mRNA and then translated into protein, in general, …

Gene duplication can give rise to homologous genes that are part of gene families. For example, there are six actin genes in the genome of most mammalian species. In humans, the ACTB gene, which encodes a cytoskeletal actin, is expressed ubiquitously, while ACTC1 is expressed mainly in cardiac cells. Although bacteria lack the eukaryotic cytoskeletal organization, 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?

Which of the following is true regarding Escherichia coli?

All cells …

Comparing the genomes of present-day mitochondria or chloroplasts with the genomes of their corresponding bacteria reveals that these organelles do not have many of the genes that are essential for their function. For instance, they lack the many genes that are required for DNA replication. What has happened to these genes?

Which of the following does NOT typically involve horizontal gene transfer?

Judged by the average number of nucleotide-pair differences per 1000 nucleotide pairs, which of the following pairs show the highest difference?