What is phagocytosis? What does it involve?
What will be an ideal response?
Phagocytosis is a process by which a cell can engulf substances and internalize them into the cytoplasm. Cells that are capable of phagocytosis are collectively known as phagocytes and include neutrophils, eosinophils, dendritic cells, and macrophages. Phagocytosis is part of the body's second line of defense, and it is nonspecific. It includes the following steps:
Chemotaxis: a cell moves either toward or away from a chemical stimulus.
Adherence: the phagocyte attaches to the pathogen, through binding of complementary chemicals on the membranes of the pathogen.
Ingestion: after the pseudopodia adhere to the pathogen, the encompassed microbe is internalized as the pseudopodia fuse to form a sac called a phagosome.
Digestion: lysosomes with over 30 digestive enzymes attach to the phagosome and break down the microbe. At the end of this process, the remains of the phagosome are known as the residual body.
Elimination: the phagocyte rids itself of undigested material by exocytosis, which is the opposite of ingestion.
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Terry takes the body of the snakelike organism and slices it open along its dorsal side. If it is a hagfish, what should Terry see?
A) a well-developed series of bony vertebrae surrounding the spinal cord B) a well-developed series of cartilaginous vertebrae surrounding the spinal cord C) a tube of cartilage (surrounding the notochord) with dorsal projections on both sides of the spinal cord D) a notochord, located underneath the spinal cord
What was the major contribution of Gregor Mendel?
a. He coined the term genes. b. He provided evidence for how traits are inherited. c. He described how genes code for particular proteins. d. He explained the central role of proteins in the expression of traits.
What can result in speciation within a few generations?
A. Development of a physical barrier B. Polyploidy arising in a plant species C. Postzygotic isolating mechanisms D. Change in environmental conditions E. The introduction of a new predator into an area
Which of the following processes requires a carrier protein?
A) diffusion only B) facilitated diffusion only C) active transport only D) endocytosis only E) both facilitated diffusion and active transport