Mastering A&P Chapter 3 - Cells: The Living Units
Which organelle is responsible for synthesizing proteins? rough endoplasmic reticulum Golgi apparatus ribosomes smooth endoplasmic reticulum
Ribosomes Proteins are synthesized at ribosomes. Free ribosomes float freely in the cytoplasm and produce soluble proteins that function in the cytosol, as well as those imported into mitochondria and some other organelles. Fixed ribosomes, which stud the rough endoplasmic reticulum, synthesize proteins destined either for incorporation into the cell membrane or lysosomes, or for export from the cell.
Which of the following organelles is correctly paired with its function? smooth endoplasmic reticulum: metabolism of lipids mitochondrion: packaging proteins and lipids lysosome: protein synthesis Golgi apparatus: produce energy for the cell
Smooth endoplasmic reticulum: metabolism of lipids This answer is correct. The smooth ER also plays a role in synthesizing steroid hormones, absorbing and transporting fats, detoxifying toxins, and breaking down glycogen.
What major function occurs on the specific membranes indicated by A? replication of DNA production of most of the cell's ATP digestion of ingested food synthesis of proteins
Synthesis of secreted proteins Structure A is the rough endoplasmic reticulum (ER). The figure illustrates how proteins are synthesized on ribosomes bound to the rough ER, sorted in the Golgi, and delivered to the plasma membrane for secretion or packaged into lysosomes.
What can we infer if we see a large number of mitochondria in a cell? The cell builds a lot of cholesterol. The cell packages a great deal of proteins for secretion. The cell produces a great deal of protein. The cell has a great metabolic demand.
The cell has a great metabolic demand. Mitochondria are threadlike or lozenge-shaped membranous organelles. In living cells they squirm, elongate, and change shape almost continuously. They are the power plants of a cell, providing most of its ATP supply.
What is the structure at A? the nucleolus a chromosome the nucleus the nuclear envelope SubmitMy AnswersGive Up Provide FeedbackContinue
The nucleolus The nucleolus is an area within the nucleus associated with ribosome construction.
What is the function of the structures at D? they are enzymes for the replication of DNA to act as attachment points for spindle fibers during cell replication to act as an assembly point for ribosomes to allow large molecules, with the exception of DNA, to pass through the envelope
To allow large molecules, with the exception of DNA, to pass through the envelope Nuclear pores allow ribosomes, mRNA, and many other large molecules to pass but contain the DNA within the nucleus.
In leukemia, an overproduction of abnormal white blood cells can also mean __________. that healthy blood cells will die sooner too few normal blood cells more reactive white blood cells overproduction of normal blood cells
Too few normal blood cells
Which cellular organelle is seen in this figure? Structure of a mitochondrion. Which cellular organelle is seen in this figure? Structure of a mitochondrion. the nucleus a lysosome a mitochondrion the Golgi apparatus
A mitochondrion Mitochondria are characterized by an oblong shape with inner and outer membranes.
What is the difference between active and passive transport across the plasma membrane? Active transport is used to move substances down their concentration gradient, whereas passive transport is used to move substances against their concentration gradient. Active transport means that the cell is actively going after substances that it wants to bring into the cell, whereas passive transport means that the cell just waits for the substance to cross the membrane. Active transport implies that the cell is working with other cells, whereas passive transport implies that the cell does not cooperate with other cells. Active transport is ATP dependent, whereas passive transport uses only the kinetic energy of the particles for movement across the plasma membrane.
Active transport is ATP dependent, whereas passive transport uses only the kinetic energy of the particles for movement across the plasma membrane. In active transport, the cell provides the metabolic energy (ATP) needed to move substances across the plasma membrane (against their concentration gradient). In passive transport, substances cross the plasma membrane (down their concentration gradient) using kinetic energy, without any energy input from the cell.
Which of the following is not required for osmosis to occur? selectively permeable membrane cellular energy concentration gradient water
Cellular energy Osmosis is a special type of diffusion, which is always a passive process.
Which of the following names the three main parts of a human cell? cytoplasm, plasma membrane, and nucleus mitochondria, lysosome, and centriole plasma membrane, mitochondria, and nucleus cytosol, nucleus, and membrane
Cytoplasm, plasma membrane, and nucleus
Which of the following statements is true? Endocytosis and exocytosis are passive transport mechanisms. During exocytosis, substances from inside the cell are moved outside. Unlike endocytosis, exocytosis does not rely on protein interactions with the plasma membranes. Exocytosis involves infolding of the plasma membrane.
During exocytosis, substances from inside the cell are moved outside. Vesicular transport processes that eject substances from the cell interior into the extracellular fluid are called exocytosis. Exocytosis is a form of active transport; thus, it requires energy, usually in the form of ATP.
Normal leukocytes use several protective mechanisms in combating disease-causing microbes such as bacteria. Which of the following is NOT a method related to substance uptake by a white blood cell? exocytosis phagocytosis pinocytosis receptor-mediated endocytosis
Exocytosis
What process is indicated by C? exocytosis of ribosomes from the cell exocytosis of secretory proteins exocytosis of RNA from the cell digestion of food particles
Exocytosis of secretory proteins The event indicated by C includes the fusion of a secretory vesicle with the plasma membrane and the subsequent release of the vesicle contents to the extracellular space.
Channel-mediated diffusion is a form of active transport. True False
False Channel-mediated diffusion is a form of passive, not active, transport. Any type of diffusion results from substances moving down their concentration gradient, a form of kinetic energy. In order to move, or actively pump, substances against their concentration gradient, energy must be used. ATP directly, or indirectly, provides the energy for active transport.
Drinking alcohol makes the blood hypertonic. Which option best describes the consequences of this hypertonic blood? Hypertonic blood will lose water to the interstitial fluid, which makes the interstitial fluid hypertonic. This, in turn, causes water to move into the cell. Hypertonic blood draws water out of the interstitial fluid, which makes the interstitial fluid hypertonic. This, in turn, draws water out of the cells. Hypertonic blood forces water into the interstitial fluid, which makes the interstitial fluid hypotonic. This, in turn, makes the interstitial fluid lose water to the cells. Hypertonic blood draws water out of the interstitial fluid, which makes the interstitial fluid hypotonic. This, in turn, makes the interstitial fluid lose water to the cells.
Hypertonic blood draws water out of the interstitial fluid, which makes the interstitial fluid hypertonic. This, in turn, draws water out of the cells. If the blood is hypertonic compared to the interstitial fluid (IF), the IF has a greater concentration of water. This means water will move from the IF toward the blood. As water leaves the IF space, that space would then become hypertonic compared to the cell, causing the same movement to occur.
What is the function of the organelle indicated by B? modification and packaging of proteins cellular division assembling proteins from amino acids catabolism of fats and sugars
Modification and packaging of proteins The Golgi apparatus within the endomembrane system functions in the sorting and modifying of membrane- bound proteins being transported to various cellular locations.
Which set of membrane proteins in the figure depicts the transport of solute molecules across the membrane? Four roles of plasma membrane proteins.
Panel A shows both passive and active transport processes of solutes mediated by integral membrane proteins.
Which set of membrane proteins in the figure depicts an interaction between two separate cells?
Panel D shows recognition of one cell by another via the glycocalyx.
Which of the following is a component of the plasma membrane that creates a chemical barrier between the inside and the outside of the cell? cholesterol water proteins phospholipids
Phospholipids The plasma (cell) membrane is a phospholipid bilayer, composed of two parallel sheets of phospholipid molecules lying tail to tail, with their polar heads exposed to water on either side of the membrane. Each lollipop-shaped phospholipid molecule has a polar "head" that is charged and is hydrophilic (hydro = water, philic = loving), and an uncharged, nonpolar "tail" that is made of two fatty acid chains and is hydrophobic.
If a person is severely dehydrated, their extracellular fluids will become hypertonic to the intracellular fluid. What do you predict will happen to the person's cells? The cells will swell. The cells will lose water and shrink. Extracellular fluids do not impact cell size, because cells contain intracellular fluid. The cells will rupture.
The cells will lose water and shrink. The hypertonic extracellular fluid will draw water out of the hypotonic intracellular fluid, so the cells will shrink. This is called crenulation.
Which of the following is characteristic of cilia? They are substantially longer than flagella, and are less common than flagella in humans. They are whiplike, motile cellular extensions that occur in large numbers on the exposed surfaces of certain cells. They are used for cellular adhesion. They move substances in many directions across a cell's surfaces.
They are whiplike, motile cellular extensions that occur in large numbers on the exposed surfaces of certain cells. Cilia are whiplike, motile cellular extensions that occur, typically in large numbers, on the exposed surfaces of certain cells. Ciliary action moves substances in one direction across cell surfaces. Centrioles forming the bases of cilia and flagella are commonly referred to as basal bodies.
Which of the following is characteristic of cilia? They move substances in many directions across a cell's surfaces. They are whiplike, motile cellular extensions that occur in large numbers on the exposed surfaces of certain cells. They are used for cellular adhesion. They are substantially longer than flagella, and are less common than flagella in humans.
They are whiplike, motile cellular extensions that occur in large numbers on the exposed surfaces of certain cells. Cilia are whiplike, motile cellular extensions that occur, typically in large numbers, on the exposed surfaces of certain cells. Ciliary action moves substances in one direction across cell surfaces. Centrioles forming the bases of cilia and flagella are commonly referred to as basal bodies.
In their resting state, all body cells exhibit a resting membrane potential; therefore, all cells are polarized. True False
True All cells that have a resting membrane potential (RMP), such that the inside (interior surface) of the cell membrane has a net negative charge while the outside (external surface) of the membrane has a net positive charge. Given the different (opposite) charges on either side of the cell membrane, the cell is considered to be polarized. This RMP, which results from separation of charged particles (ions) across the cell membrane, can be measured in millivolts (typically ranging from -50 to -100 mV depending on the cell type).
Lysosomes perform digestive functions within a cell. True False
True Born as endosomes that contain inactive enzymes, lysosomes are spherical, membranous organelles containing activated digestive enzymes. Lysosomes are large and abundant within phagocytes, the cells that dispose of invading bacteria and cell debris. Lysosomal enzymes can digest almost all kinds of biological molecules. They work best in acidic conditions and so are called acid hydrolases.
What is a membrane potential? the ability of the cells to perform their specialized functions a voltage or electrical charge across the plasma membrane the possibility of cell activity cooperation between cells
a voltage or electrical charge across the plasma membrane The membrane potential is the electrical potential energy (measured in millivolts) resulting from the separation of oppositely charged particles (ions) across the plasma membrane. At rest, membrane potentials are typically negative, ranging from −50 to −100 mV, with more anions (than cations) concentrated along the internal surface of the membrane, and more cations (than anions) concentrated along the external surface.
Which of the following solutions contains the most solute? hypotonic equilibrium isotonic hypertonic
hypertonic "Hyper" means "high," so a hypertonic solution has a higher solute concentration than the solution to which it is being compared.
In general, to maintain homeostasis the relationship between our intracellular and extracellular fluids should be which of the following? isotonic to each other intracellular should be hypertonic to extracellular intracellular should be hypotonic to extracellular intracellular and extracellular should both be hypertonic
isotonic to each other In order to prevent the cells from either swelling or shrinking, the body fluids should be isotonic, meaning that they are at equilibrium.