Which of the following describes the anatomy of a coenocytic organism?The body is made of a large cell with many nuclei.Bulk flow is completely independent of diffusion; diffusion does not occur anywhere in the body of an organism that demonstrates bulk flow.FalseMany of the signaling pathways used for signaling between cells in complex multicellular organisms first evolved in:unicellular eukaryotes.During animal development, a fertilized egg divides to form a ball of undifferentiated cells called a:blastula.Similar patterns of character acquisition leading to complex multicellularity are seen in plants and animals.TrueMost taxonomic groups that include simple multicellular organisms never gave rise to complex multicellular descendants.TrueWhich of the following statements are true regarding sponges?The structure of sponges—especially the pores and canals—allows sponges to achieve sizes of up to a meter (or more).Which of the following statements about plants and animals is false?Complex multicellularity arose in the common ancestor of plants and animals and was retained in each of these groups.Which of the following statements about oxygen is false?Oxygen is the only potential electron acceptor available on Earth's surface.A young student is trying to recapitulate an experiment discussed in the text. She introduces single-celled green algae into a petri dish containing predatory protists. After several generations, what will she observe?Green algae will form multicellular colonies.A young medical student has removed a tendon, intestine, and heart from a cadaver. When he flattens all of these structures (and stretches them out to their utmost extent), he notices that the intestine is by far the largest structure. Why?The intestine must have a large surface area over which nutrients derived from food can diffuse into the bloodstream.Which of the following traits of complex multicellular organisms is also shared by some single-celled organisms?adhesionYou may have noticed that a plant placed on a windowsill will eventually bend toward a light source. This is likely due to the fact that in response to a light source:plant cells on one side of the stem will elongate.Which of the following traits of complex multicellular organisms is also shared by some simple multicellular organisms, but not by single-celled organisms?plasmodesmataWhich of the following statements about the evolution of complex multicellularity is true?Complex multicellularity evolved independently at least six times in different groups of organisms.Although choanoflagellates are fundamentally unicellular organisms, they possess genes that code for cadherins and integrins. Which of the following hypotheses regarding the function of these molecules in choanoflagellates is supported by laboratory experiments?Choanoflagellates use adhesion molecules to help capture bacterial prey.A jellyfish relies on diffusion to provide oxygen to its body cells, and yet it is much larger than the 1 cm limit imposed by diffusion. How can it be so thick and still meet its metabolic demands by diffusion alone?Much of the thickness of a jellyfish consists of metabolically inert materials that do not require oxygen.Which of the following statements contrasting simple and complex multicellularity is true?Complex multicellular organisms show a large degree of cellular differentiation, whereas simple multicellular organisms show little differentiation into specialized cell types.A young boy is staring at the tropical fish tank in his mother's office. He reaches in and pulls out a fern-like plant. When he closely examines this plant, he notices it has very large cells with several dark spots. What is likely true of this plant?This plant is coenocytic; the dark spots are actually nuclei.In animals, fungi, and plants, bulk flow is always an active and ATP-expensive process. This is best evidenced by the need for a heart to beat in order for bulk flow to occur in animals.FalseWhich of the following statements about the evolution of animal cell adhesion molecules is true?Animal cell adhesion molecules evolved from protein families that originally performed other functions.Which of the following statements regarding a simple multicellular organism is true?If a single cell is removed from a simple multicellular organism, it may be able to reproduce on its own.Which of the following statements about cell signaling is correct?Signaling pathways and the molecules involved (e.g., kinases) evolved before the evolutionary split between plants and animals and thus are similar in the two groups.The mesoglea of jellyfish:provides structural support to the jellyfish body and would be considered a metabolically inactive tissue.Which of the following statements is false?Complex multicellularity does not involve the differentiation of cells with distinct shapes and functions.Which of the following statements is true regarding bulk flow in both animals and plants?Bulk flow is responsible for the movement of nutrients and hormones in both animals and plants.A young student is trying to recapitulate an experiment discussed in the text. She introduces single-celled green algae into a petri dish containing predatory protists. After several generations, what will she observeGreen algae will form multicellular colonies.Which of the following statements about adhesion molecules is false?Cadherins and pectins are both transmembrane proteins.Which of the following statements about bulk flow is false?Bulk flow is found in simple multicellular organisms, but not unicellular organisms.The differentiation of distinct cell types is a biological innovation that accompanied the evolution of complex multicellularity.TrueWhich of the following is a term describing a multinucleated organism made up of a single cell?coenocyticMultiple lines of evidence indicate that complex multicellularity has evolved at least six different times. Which of the following superkingdoms include organisms that exhibit complex multicellularity?Opisthokonta, Archaeplastida, StramenopilaWhich one of the following is the definition of diffusion?the tendency of molecules to move in space due to kinetic energyFor multicellularity to develop, there must be a mechanism of signaling among cells in the multicellular organism. Which of the following structures present in the cell membrane receives signals from the environment, or other cells?receptorsChoanoflagellates are:protistsAn undifferentiated cell in animals that can develop into any of several differentiated cell types is called a:stem cell.In what types of multicellular organisms do plasmodesmata serve as a mechanism of cell-cell signaling?plantsWhich of the following statements is TRUE?
Integrins and cadherins facilitate cell adhesion to extracellular substrates.
Integrins on one cell attach to cadherins on another cell to promote cell adhesion.
Cadherins on the surface of animal cells permit cells to adhere to other cells.
Cadherins are used in plant cells to attach the plasma membrane to the cell wall.Cadherins on the surface of animal cells permit cells to adhere to other cells.Which one of the following is a major difference between plants and animals?Plant cells have walls; animal cells do not.The branch of biology known as evolutionary-developmental biology is the study of:how changes in development underpin the evolution of morphology.
