Chapter 3: The Living Units

True/False The speed of individual particle diffusion is influenced by temperature and particle size, not by concentration.

True

Cancerous cells can divide so rapidly that they will often produce a glycocalyx that is different than the other cells in the body. This may result in ________. A) allowing the cancer cells to bind to their healthy, neighboring cells B) a decrease in the permeability of the tumor cell's plasma membrane preventing the uptake of chemotherapy drugs C) the cancer cells conserving energy for more growth D) cells of the immune system recognizing the tumorous cells as foreign and destroying the

d

If a human cell were to increase the amount of cholesterol embedded within its plasma membrane which of the following would most likely happen? A) The plasma membrane would become more permeable to ions and less permeable to lipids. B) The cell would form a plaque that could potential block a blood vessel. C) The plasma membrane would become more fluid and the phospholipids less stable. D) The plasma membrane would become more stable, less fluid and less permeable

d

Mitochondria ________. A) are single-membrane structures involved in the breakdown of ATP B) synthesize proteins for use outside the cell C) contain digestive enzymes called acid hydrolyses D) contain some of the DNA and RNA code necessary for their own function

d

Peroxisomes ________. A) sometimes function as secretory vesicles B) are functionally the same as lysosomes C) function to digest particles ingested by endocytosis D) are able to detoxify substances by enzymatic action

d

True/False Aquaporins are believed to be present in red blood cells and kidney tubules, but not in any other cells in the body.

False

True/False DNA transcription is another word for DNA replication.

False

True/False Microfilaments are thin strands of the contractile protein composed of myosin.

False

True/False Osmosis is the passive movement of water but it follows almost completely opposite laws of physics when compared to the diffusion of ions or other small particles.

False

True/False Telomeres are the regions of chromosomes that code for the protein ubiquitin.

False

True/False The genetic information encoded in DNA by the regular alternation of sugar and phosphate molecules.

False

True/False The glycocalyx is composed of glycolipids, glycoproteins and cholesterol molecules that are displayed on the outside surface of the plasma membrane

False

True/False Apoptosis is programmed cell suicide; cancer cells do not undergo this process.

True

True/False Concentration differences cause ionic imbalances that polarize the cell membrane, and active transport processes

True

True/False Dividing cells must pass through the phases of mitosis the following order: Prophase, Metaphase, Anaphase, and Telophase

True

True/False Each daughter cell resulting from mitotic cell division has the exactly same genetic composition

True

True/False Enzymes and proteins needed for cell division are synthesizes and put into place during G2 phase

True

True/False Interstitial fluid represents one type of extracellular material.

True

True/False Introns represent a genome scrap yard that provides DNA segments for genome evolution and a variety of small RNA molecules.

True

True/False Lipid rafts, found in the cell outer membrane surface, are concentrating platforms for certain receptor molecules or for protein molecules needed for cell signaling

True

True/False Microtubules are hollow tubes made of subunits of the protein tubulin.

True

A cell engulfing a relatively large particle will likely utilize ________. A) phagocytosis B) pinocytosis C) receptor-mediated endocytosis D) exocytosi

a

A gene can best be defined as ________. A) a segment of DNA that carries the instructions for one polypeptide chain B) a three-base triplet that specifies a particular amino acid C) noncoding segments of DNA up to 100,000 nucleotides long D) an RNA messenger that codes for a particular polypeptide

a

If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon. A) UCG B) TCG C) UGA D) AUG

a

If active transport establishes a concentration gradient with the use of ATP, then the concentration gradient can be looked at as ________. A) potential energy that can be harnessed when molecules passively diffuse down the concentration gradient B) a byproduct of active transport that will be alleviated by pinocytosis C) an unusable byproduct of active transport that will simply diffuse away D) unwanted pressure that will be alleviated by channel mediated facilitated diffusion

a

The myocardium (cardiac muscle tissue) undergoes a significant amount of physical stress due to its contractions. You would expect to see relatively large numbers of which of the following embedded within their plasma membrane? A) tight junctions B) desmosomes C) glycolipids D) transport proteins

b

If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable, what could happen? A) The cells will lose water and shrink. B) The cells will show no change due to diffusion of both solute and solvent. C) The cells will swell and ultimately burst. D) The cells will shrink at first, but will later reach equilibrium with the surrounding solution and return to their original condition.

a

The lungs deliver a regular supply of oxygen to the blood, which is in turn circulated to most all the cells of the body. At the same time oxygen is consumed during aerobic cellular respiration within these cells. This implies that ________. A) oxygen will passively diffuse into the cells B) oxygen requires active transport to enter most cells C) the concentration gradient for oxygen is steepness inside of the cell D) the rate of oxygen diffusion is independent of concentratio

a

The lungs deliver a regular supply of oxygen to the blood, which is in turn circulated to most all the cells of the body. At the same time oxygen is consumed during aerobic cellular respiration within these cells. This implies that ________. A) oxygen will passively diffuse into the cells B) oxygen requires active transport to enter most cells C) the concentration gradient for oxygen is steepness inside of the cell D) the rate of oxygen diffusion is independent of concentration

a

Which of the following describes the plasma membrane? A) a phospholipid bilayer surrounding the cell B) a membrane composed of tiny shelves or cristae C) a double layer of protein enclosing the plasma D) a single-layered membrane that surrounds the nucleus of the cell

a

Which of the following is a function of a plasma membrane protein? A) molecular transport through the membrane B) forms a lipid bilayer C) circulating antibody D) oxygen transport

a

Which of the following is a principle of the fluid mosaic model of cell membrane structure? A) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules. B) Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains. C) All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell. D) The lipid bilayer is a solid at body temperature, thus protecting the cell.

a

Which of the following statements is correct regarding net diffusion? A) The greater the concentration gradient, the faster the rate. B) The lower the temperature, the faster the rate. C) The rate is independent of temperature. D) Molecular weight of a substance does not affect the rate

a

Which of the following will NOT speed up the net rate of diffusion for glucose into a cell? A) Decreasing the number of phospholipids in the plasma membrane B) Increasing the concentration of glucose outside of the cell. C) Increasing the number of glucose transport proteins within the plasma membrane. D) Decreasing the concentration of glucose within the cell

a

A red blood cell placed in pure water would ________. A) neither shrink nor swell B) swell and burst C) swell initially, then shrink as equilibrium is reached D) shrink

b

A type of transport protein found in the plasma membrane of cells lining the inside of the intestine allows sodium ions to diffuse down their concentration gradient. The ions move through the transport protein, and into the cell. These transport proteins will use the kinetic energy of the diffusing sodium ions to bring glucose into the cells as well. Which of the following would stop transport of glucose through this transport protein? A) Increasing the number of digestive enzymes in the digestive tract. B) Stopping the activity of the sodium potassium pump. C) Increasing the concentration of glucose outside of the cell. D) Lowering the energy of activation.

b

Bone is a connective tissue that provides support for the body with its strength and rigidity. Which of the following provides the best explanation for how this is so? A) Bone cells are very dense and therefore resist physical stress. B) Bones cells secrete an extracellular matrix that when combined with minerals becomes rock hard. C) Bone cells have extensive cytoskeleton that makes them ridged. D) The bone cell's plasma membrane contains a high degree of cholesterol that stabilizes the cell membrane, giving it strength

b

If a cell is non-selectively engulfing samples of extracellular fluid, for example to absorb nutrients, it will likely utilize ________. A) phagocytosis B) pinocytosis C) receptor-mediated endocytosis D) exocytosis

b

If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA? A) ACGTT B) GUACC C) UGCAA D) TGCAA

b

Mitosis ________. A) creates diversity in genetic potential B) is division of the genetic material within the nucleus C) is always a part of the cell cycle D) is the formation of sex cell

b

Passive membrane transport processes include ________. A) the use of transport proteins when moving substances from areas of low to high concentration B) movement of a substance down its concentration gradient C) consumption of ATP D) movement of water from an area of high solute concentration to an area of low concentratio

b

Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to ________. A) specific codes from the DNA B) changes in the environment C) the presence or absence of ubiquitins D) specific tRNAs

b

Some hormones enter cells via ________. A) exocytosis B) receptor-mediated endocytosis C) primary active transport D) pinocytosis

b

The main component of the cytosol is ________. A) sugars B) water C) proteins D) salt

b

Which of the following is FALSE regarding the membrane potential? A) The resting membrane potential is determined mainly by the concentration gradients and differential permeability of the plasma membrane to K+ and Na+ions. B) The resting membrane potential is maintained solely by passive transport processes. C) The resting membrane potential occurs due to active transport of ions across the membrane due to the sodium-potassium pump. D) In their resting state, all body cells exhibit a resting membrane potential

b

Which of the following is NOT a function of lysosomes? A) degrading worn-out or nonfunctional organelles B) help in the formation of cell membranes C) digesting particles taken in by endocytosis D) breaking down bone to release calcium ions into the bloo

b

Which of the following would NOT assist in establishing a resting membrane potential? A) Having greater concentration of glycolipids on the outside surface of the membrane. B) Selective diffusion allowing more uncharged particles into the cell. C) Selective diffusion allowing more positively charged ions to diffuse out of the cell. D) Selective diffusion allowing fewer positively charged ions to diffuse into the cell

b

Which transport process is the main mechanism for the movement of most macromolecules by body cells? A) secondary active transport B) receptor-mediated endocytosis C) pinocytosis D) phagocytosis

b

Beta cells in the pancreas produce and secrete the protein hormone insulin. You would expect to see a relatively large amount of which organelles in these cells? A) cytoskeleton, and peroxisomes B) mitochondria, and cilia C) Golgi apparatus, rough endoplasmic reticulum D) smooth endoplasmic reticulum, and lysosomes

c

If a cell is selectively reducing the concentration of a particular enzyme in the extracellular fluid it will likely utilize ________. A) phagocytosis B) pinocytosis C) receptor-mediated endocytosis D) exocytosis

c

In certain kinds of muscle cells, calcium ions are stored in ________. A) the cytoplasm B) both smooth and rough ER C) the smooth ER D) the rough E

c

Myocardium (cardiac muscle tissue) must rhythmically contract for a lifetime. This requires a considerable amount of energy production by the cells. You would expect to see a relatively high amount of which organelle in these cells? A) cytoskeleton B) smooth endoplasmic reticulum C) mitochondria D) lysosome

c

The RNA responsible for bringing the amino acids to the ribosome for protein formation is ________. A) mRNA B) rRNA C) tRNA D) ssRN

c

The electron microscope has revealed that one of the components within the cell consists of pinwheel array of 9 triplets of microtubules arranged to form a hollow tube. This structure is a ________. A) centrosome B) ribosome C) centriole D) chromosom

c

Which of the following is NOT a function of the smooth endoplasmic reticulum? A) breakdown of stored glycogen to form free glucose B) steroid-based hormone synthesis C) protein synthesis in conjunction with ribosomes D) lipid metabolism and cholesterol synthesis

c

Which of the following is not a factor that binds cells together? A) special membrane junctions B) glycoproteins in the glycocalyx C) glycolipids in the glycocalyx D) wavy contours of the membranes of adjacent cells

c

Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"? A) Second messengers usually inactivate protein kinase enzymes. B) Second messengers usually act to remove nitric oxide (NO) from the cell. C) Cyclic AMP and calcium may be second messengers. D) Second messengers act through receptors called K-proteins

c

Which of the following would not be a constituent of a plasma membrane? A) glycoproteins B) glycolipids C) messenger RNA D) phospholipid

c

The functions of centrioles include ________. A) producing ATP B) serving as the site for ribosomal RNA synthesis C) providing a whiplike beating motion to move substances along cell surfaces D) organizing the mitotic spindle in cell division

d

When tissues are injured or infected, chemical signals can be releases that affect the plasma membrane of cells that line the nearby blood vessels. These blood vessels cells (endothelial cells) respond to the chemical signals by displaying a type of glycoproteins on their surface. These proteins will attach to circulating white blood cells bringing them to the site of injury or infection. These glycoproteins would best be described as ________. A) desmosomes B) G-proteins C) transport proteins D) Cell Adhesion Molecules (CAMs

d

Which of the following statements is correct regarding RNA? A) rRNA is always attached to the rough ER. B) If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU. C) There is exactly one specific type of mRNA for each amino acid. D) Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis

d

Which of the following structures would aid a cell in allowing more nutrients to be absorbed by the cell? A) stereocilia B) flagella C) primary cilia D) microvilli

d

Which of the following would not be restricted (limited) by low levels of ATP? A) exocytosis B) pinocytosis C) phagocytosis D) osmosis

d

Which of these is an inclusion, not an organelle? A) lysosome B) microtubule C) cilia D) melanin

d