Exam 1: Cells: The Fundamental Units of Life

The protozoan Didinium feeds on other organisms by engulfing them.Describe the cellular characteristics necessary to feed this way and explain why this is not a mechanism by which bacteria can acquire energy.Are bacteria, in general, unable to feed on other cells in this way?

Living systems are incredibly diverse in size, shape, environment, and behavior.It is estimated that there are between 10 million and 100 million different species.Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive.Which of the following can be described as the smallest living unit?

Cellular processes are often regulated by unknown mechanisms.In many cases, biologists work backward in an attempt to understand a process in which they are interested.This was the case when Nurse and Hartwell were trying to understand how cell division is controlled in yeast.Describe the process by which they "broke" the system and then supplied the "missing parts" to get the cell cycle running again.What further evidence did they collect to show that human cells and yeast cells regulate the cell cycle using a similar mechanism?

Select the option that correctly finishes the following statement: A cell's genome

Genes that have homologs in a variety of species have been discovered through the analysis of genome sequences.In fact, it is not uncommon to find a family of homologous genes encoding proteins that are unmistakably similar in amino acid sequence in organisms as diverse as budding yeast, archaea, plants, and humans.Even more remarkably, many of these proteins can substitute functionally for their homologs in other organisms (i.e., if we delete a native gene and replace it with a homologous gene from another species, the protein will be produced and its function preserved).Use your understanding of evolution to explain how this is possible.

__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species.These chemicals are both generated and broken down in the same location.

The cytoskeleton provides support, structure, motility, and organization, and it forms tracks to direct organelle and vesicle transport.Which of the cytoskeletal elements listed below is the thickest?

Use the list of structures below to label the schematic drawing of an animal cell in Figure 1-41. Figure 1-41 A.plasma membrane B.nuclear envelope C.cytosol D.Golgi apparatus E.endoplasmic reticulum F.mitochondrion G.transport vesicles

Eukaryotic cells are able to trigger the release of material from secretory vesicles to the extracellular space using a process called exocytosis.An example of materials commonly released this way is

You have been following the recent presidential elections and have heard some candidates disparaging excessive and "unnecessary" federal government expenditures.One particular candidate asks: "Why are we spending millions of dollars studying fruit flies? How can that possibly help us find a cure for cancer?" Use your knowledge of model organisms to explain why studies in D.melanogaster (the fruit fly) are actually an excellent use of research funding.

Number the following cells based on when they are believed to have evolved. ___ anaerobic eukaryote ___ aerobic prokaryote ___ anaerobic prokaryote ___ photosynthetic eukaryote ___ aerobic eukaryote ___ photosynthetic prokaryote

Identify the appropriate cell type in which the listed structure or molecule can be found.Note that the structure or molecule can be found in more than one type of cell. 1 DNA 2 nucleus 3 plasma membrane 4 chloroplast 5 cell wall 6 lysosome 7 mitochondrion 8 Golgi apparatus animal plantbacterial animalplantbacterial animal plantbacterial animalplantbacterial animal plant bacterial animalplant bacterial animal plantbacterial animal plant bacterial Figure 1-71

Changes in DNA sequence from one generation to the next may result in offspring that are altered in fitness compared with their parents.The process of change and selection over the course of many generations is the basis of

Which statement is NOT true about the events/conclusions from studies during the mid-1800s surrounding the discovery of cells?

Select the option that BEST finishes the following statement: Evolution is a process

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once. amino acids micrometer(s) viruses DNA millimeter(s) yeast fatty acids plants meter plasma membranes Cells can be very diverse: superficially, they come in various sizes, ranging from bacterial cells such as Lactobacillus, which is a few __________ in length, to larger cells such as a frog's egg, which has a diameter of about 1 __________.Despite the diversity, cells resemble each other to an astonishing degree in their chemistry.For example, the same 20 __________ are used to make proteins.Similarly, the genetic information of all cells is stored in their __________.Although __________ contain the same types of molecules as cells, their inability to reproduce themselves by their own efforts means that they are not considered living matter.

Which pair of values best fills in the blanks in this statement: On average, eukaryotic cells are __________ times longer and have __________ times more volume than prokaryotic cells.