Name: ___________________________ Class: _________________ Date: __________
Test Bank For Molecular Biology of the Cell, 7th Edition by Bruce Alberts (Author), Rebecca Heald (Author), Alexander Johnson (Author), Chapter 1-24 Answers are at the End of Each Chapter
chapter 1 1. What are the benefits of studying ―the human genome?‖ People from a certain ethnic group tend to have more commonalities in their genomes than they do with those outside of their ethnic group. If researchers intend for their genomic studies to benefit all groups of people, why might it be important to ensure that there is adequate representation from all ethnic groups in human genome databases? Justify your response in 2-3 sentences.
2. In this chapter, several model organisms are discussed. Based on what you have learned about why researchers use these organisms, explain what sorts of qualifications make for a good model organism.
3. All the cells in a multicellular organism contain the same DNA despite the massive differences in those cells’ appearance and function. Explain how this is possible.
4. While oceans cover approximately 70% of the earth’s surface, only 1% of the earth’s biomass is present there. Considering that the largest contributor to earth’s biomass is plants, why do you think most of the earth’s biomass is terrestrial instead of in the oceans?
5. A scientist has four different samples: a rod-shaped bacterial cell with flagella from a thermal vent deep in the ocean, a spherical bacterial cell from the glaciers high in the Himalayas, a yeast cell from bread, and a single-celled protist with cilia from a pond. Explain the best way to understand the evolutionary relationships between these four organisms. Why does this method work better than others?
6. If animals are found in an isolated ecosystem, there should be photosynthetic organisms in that ecosystem as well. a. True b. False
7. Which of the following descriptions match lithotrophic, organotrophic, and phototrophic organisms, respectively? a. Lithotrophic b. Organotrophic c. Phototrophic
1. They feed on other living organisms or their organic products. 2. They are responsible for the current oxygen-rich atmosphere of the Earth. 3. They are all known to be prokaryotic. 4. They are the primary energy converters in hydrothermal vents in the ocean floor.
8. In the following paragraph, fill in the blanks with either Archaea, Bacteria, or Eukaryotes. Methanococcus jannaschii is an anaerobic thermophilic microbe that belongs to the domain _____(I)______ and is found in extreme environments such as hydrothermal vents. It lives at temperatures near the boiling point of water and at pressures over 200 times higher than at sea level. Its genome sequence, identified in 1996, revealed that most of its metabolic processes are similar to those in _____(II)______, while its genetic machinery is more similar to that of _____(III)______. a. Archaea b. Bacteria c. Eukaryotes
1. (I) 2. (II) 3. (III)
9. Which of the following descriptions match messenger RNAs, ribosomal RNAs, and transfer RNAs, respectively? a. Messenger RNAs b. Ribosomal RNAs c. Transfer RNAs
1. They contain codons. 2. They contain anticodons. 3. They are (covalently) attached to amino acids. 4. They are at the core of a complex that carries out protein synthesis.
10.Which of the following descriptions match RNA, and which match DNA? a. RNA b. DNA
1. It is mainly found as a long, double-stranded molecule. 2. It contains the sugar ribose. 3. It normally contains the bases thymine, cytosine, adenine, and guanine. 4. It can normally adopt distinctive folded shapes. 5. It can be used as the template for protein synthesis.
11.Why do viruses support the ―RNA world‖ hypothesis of how life originated? a. The smallest viruses contain only a single-stranded RNA molecule. b. Viruses use RNA molecules as catalysts. c. Viruses target and attack host RNA molecules. d. Viruses are made exclusively of RNA. e. Some viruses contain double-stranded RNA.
12.What is NOT a purpose of the 27 proteins produced by the SARS-CoV-2 genome?
a. Packaging for the viral genome b. Replicating the viral genome inside the host cell c. Assuring that the viral genes are properly translated into protein d. Evading the host cell defenses e. Decreasing the host cell’s oxygen supply
13.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. What is NOT a characteristic that describes this organism? a. It is a vertebrate. b. It is well suited for genetic analysis. c. Its early stages of development occur outside of the mother’s body. d. Its genome size is almost half that of humans. e. It can fly.
14.This model organism is 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. What is the best description of this organism? a. It is a vertebrate. b. Its genome is only 10 million nucleotide pairs long. c. There are many more duplicate genes in this organism compared to humans. d. Although useful for genetic studies, the molecular mechanisms governing its development are irrelevant to human development.
e. It normally only reproduces sexually.
15.Judged by the average number of nucleotide-pair differences per 1000 nucleotide pairs, which pair shows the highest difference? a. The genomes of S. cerevisiae and M. musculus b. The genomes of two different E. coli strains c. The ribosomal RNA genes from humans and E. coli d. The transfer RNA genes in a human and M. musculus e. The genomes of two humans
16.This model organism is used to study various eukaryotic cell and developmental processes such as cell division and cell death. Its hermaphrodite adult is composed of exactly 959 somatic (non-germ) cells, the lineage of each of which has been worked out with great precision. It is approximately 1 mm long. What is the best description of this organism? a. It is a vertebrate. b. It is a plant pathogen that destroys many crops. c. Its genome codes for a few thousand genes. d. It can fly. e. It can be frozen indefinitely in a state of suspended animation.
17.While knowing the sequence of a genome is a start to understanding the functions inside a cell, many researchers also are interested in monitoring the expression levels of all the genes in a genome. What would be an application of this technique? a. Analyzing if a gene is similar in sequence to any other genes b. Understanding how a cell responds to being placed in a tumor-promoting environment versus its normal environment