Deck 3: Cells: the Living Units

Question 1

The functions of centrioles include .

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

Answer 1

B

Question 2

Which of the following is not a factor that binds cells together?

A)glycolipids in the glycocalyx
B)special membrane junctions
C)glycoproteins in the glycocalyx
D)wavy contours of the membranes of adjacent cells

Answer 2

A

Question 3

Some hormones enter cells via _.

A)endocytosis
B)exocytosis
C)pinocytosis
D)receptor- mediated endocytosis

Answer 3

D

Question 4

Ribosomes,endoplasmic reticulum,and the Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use export)only,never for use by the cell.This statement is _.

A)true
B)false; proteins thus manufactured are for use inside the cell only
C)false; integral cell membrane proteins are also synthesized this way
D)false; lipids,not proteins,are synthesized this way

Question 5

Mitosis _ .

A)produces nucleus replication
B)is the formation of sex cells
C)creates diversity in genetic potential
D)always results in division of a cell

Question 6

In certain kinds of muscle cells,calcium ions are stored in .

A)both smooth and rough ER
B)the rough ER
C)the cytoplasm
D)the smooth ER

Question 7

Which of the following statements is correct regarding RNA?

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

Question 8

Which of the following would not be a constituent of a plasma membrane?

A)glycoproteins
B)phospholipids
C)glycolipids
D)messenger RNA

Question 9

Which of these is not a function of the plasma membrane?

A)It prevents potassium ions from leaking out and sodium ions from crossing into the cell.
B)It encloses the cell contents.
C)It is selectively permeable.
D)It acts as a site of cell- to- cell interaction and recognition.

Question 10

Which of the following is true regarding the generation of a membrane potential?

A)The maintenance of the potential is based exclusively on diffusion processes.
B)In the polarized state,sodium and potassium ion concentrations are in static equilibrium.
C)Both potassium and sodium ions can "leak" through the cell membrane due to diffusion.
D)When the sodium- potassium pump is activated,potassium is pumped into the cell twice as fast as the sodium is pumped out,thus causing the membrane potential.

Question 11

Which statement best describes transcytosis?

A)combining an endosome with a lysosome and degrading or releasing the contents
B)recycling the contents of the endosome back to the surface of the cell
C)storing the contents of the endosome
D)transporting an endosome from one side of a cell to the other and releasing the contents by exocytosis

Question 12

Extracellular matrix is .

A)a type of impermeable cell junction found in epithelia
B)not present in connective tissue
C)composed of strands of actin protein
D)the most abundant extracellular material

Question 13

Caveolae are closely associated with all but which of the following?

A)enzymes involved in cell metabolism
B)enzymes involved in cell regulation
C)receptors for hormones
D)lipid rafts

Question 14

Which of the following is a function of a plasma membrane protein?

A)circulating antibody
B)molecular transport through the membrane
C)oxygen transport
D)forms a lipid bilayer

Question 15

A gene can best be defined as .

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

Question 16

Which statement is the most correct regarding transcription/translation?

A)The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
B)The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it.
C)The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
D)The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it.

Question 17

Peroxisomes _.

A)sometimes function as secretory vesicles
B)function to digest particles ingested by endocytosis
C)are also called microbodies,and contain acid hydrolases
D)are able to detoxify substances by enzymatic action

Question 18

Which transport process is the main mechanism for the movement of most macromolecules by body cells?

A)receptor- mediated endocytosis
B)phagocytosis
C)pinocytosis
D)secondary active transport

Question 19

The electron microscope has revealed that one of the components within the cell consists of microtubules arranged to form a hollow tube.This structure is a _.

A)ribosome
B)centrosome
C)chromosome
D)centriole

Question 20

Crenation is likely to occur in blood cells in .

A)blood plasma
B)a hypotonic solution
C)an isotonic solution
D)a hypertonic solution

Question 21

Which of the following is a principle of the fluid mosaic model of cell membrane structure?

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

Question 22

Which of these is an inclusion,not an organelle?

A)lysosome
B)microtubule
C)cilia
D)melanin

Question 23

Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?

A)Second messengers usually act to remove nitric oxide NO)from the cell.
B)Cyclic AMP and calcium may be second messengers.
C)Second messengers usually inactivate protein kinase enzymes.
D)Second messengers act through receptors called K- proteins.

Question 24

Which of the following describes the plasma membrane?

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

Question 25

Passive membrane transport processes include _ .

A)consumption of ATP
B)movement of a substance down its concentration gradient
C)movement of water from an area of low concentration to an area of high concentration
D)the use of transport proteins when moving substances from areas of low to high concentration

Question 26

A red blood cell placed in pure water would .

A)neither shrink nor swell
B)swell initially,then shrink as equilibrium is reached
C)shrink
D)swell and burst

Question 27

Once solid material is phagocytized and taken into a vacuole,which of the following statements best describes what happens?

A)A ribosome enters the vacuole and uses the amino acids in the "invader" to form new protein.
B)The vacuole remains separated from the cytoplasm and the solid material persists unchanged.
C)A lysosome combines with the vacuole and digests the enclosed solid material.
D)Nitrogen enters the vacuole and "burns" the enclosed solid material.

Question 28

Which of the following statements is correct regarding diffusion?

A)The rate of diffusion is independent of temperature.
B)The lower the temperature,the faster the diffusion rate.
C)Molecular weight of a substance does not affect the rate of diffusion.
D)The greater the concentration of gradient,the faster the rate of diffusion.

Question 29

Lysosomes .

A)are the major site of protein synthesis
B)contain acid hydrolases that are potentially dangerous to the cell
C)maintain a highly alkaline internal environment
D)are always used for the cell to "commit suicide"

Question 30

Cell junctions that promote the coordinated activity of cells by physically binding them together into a cell community include all of the following except .

A)tight junctions
B)gap junctions
C)peroxisomes
D)desmosomes

Question 31

The RNA responsible for bringing the amino acids to the "factory" site for protein formation is .

A)rRNA
B)mRNA
C)ssRNA
D)tRNA

Question 32

Which of the following is not a subcellular structure?

A)cytoplasm
B)membranes
C)organelles
D)intercellular material

Question 33

Which structures are fingerlike projections that greatly increase the absorbing surface of cells?

A)stereocilia
B)cilia
C)microvilli
D)flagella

Question 34

In the maintenance of the cell resting membrane potential .

A)the inside of the cell is positive relative to its outside
B)the steady state involves only passive processes in all cells
C)extracellular sodium levels are high
D)cells are more permeable to Na+ than K+

Question 35

If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable,what could happen?

A)The cells will show no change due to diffusion of both solute and solvent.
B)The cells will shrink at first,but will later reach equilibrium with the surrounding solution and return to their original condition.
C)The cells will lose water and shrink.
D)The cells will swell and ultimately burst.

Question 36

If a tRNA had an AGC anticodon,it could attach to an)mRNA codon.

A)TCG
B)AUG
C)UCG
D)UGA

Question 37

The main component of the cytosol is _.

A)salts
B)proteins
C)sugars
D)water

Question 38

Which of the following is a concept of the cell theory?

A)A cell is the basic structural and functional unit of living organisms.
B)Simple cells can arise spontaneously from rotting vegetation.
C)Only higher organisms are composed of cells.
D)The subcellular organelle is the basic unit of life.

Question 39

Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to .

A)changes in the environment
B)specific tRNAs
C)the presence or absence of ubiquitins
D)specific codes from the DNA

Question 40

Which of the following does not serve as a signal for cell division?

A)contact inhibition
B)surface- to- volume ratio
C)repressor genes
D)joining of cyclins and Cdks

Question 41

What are cell exons and introns?

Question 42

A____________is a channel between cells.

Question 43

are hollow tubes made of spherical protein subunits called tubulins.

Question 44

What are lipid rafts? What are their functions?

Question 45

Aerobic cellular respiration occurs in the .

Question 46

What is the common route of entry for flu viruses into a cell?

Question 47

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)UGCAA
B)TGCAA
C)GUACC
D)ACGTT

Question 48

How are the products of free ribosomes different from membrane- bound ribosomes?

Question 49

is the division of the cytoplasmic mass into two parts.

Question 50

The process of discharging particles from inside a cell to the outside is called _ _.

Question 51

Why can we say that cells are protein factories?

Question 52

In all living cells hydrostatic and osmotic pressures exist.Define these pressures and explain how they are used in the concept of tonicity of the cell.

Question 53

Two very important second messengers used in the G protein- linked receptor mechanism are cyclic AMP and .

Question 54

How are peroxisomes different from lysosomes?

Question 55

Explain the term genetic code.What does it code for? What are the letters of the code?

Question 56

What are nucleolar organizer regions?

Question 57

What forces maintain a steady state "resting" membrane potential?

Question 58

How is the resting potential formed? How is it maintained?

Question 59

The most common extracellular ion is .

Question 60

The RNA that has an anticodon and attaches to a specific amino acid is RNA.

Question 61

List the steps in the process of transcription.

Question 62

Briefly name the subphases of interphase and tell what they do.

Question 63

Why can we say that a cell without a nucleus will ultimately die?

Question 64

The metabolic or growth phase of a cell life cycle is called .

Question 65

A red blood cell would swell if its surrounding solution were _.

Question 66

Other than the nucleus,which organelle has its own DNA?

Question 67

Water may move through membrane pores constructed by transmembrane proteins called .

Question 68

In order for the DNA molecule to get "short and fat" to become a chromosome,it must first wrap around small molecules called .

Question 69

Why are free radicals so dangerous to cells,and how are they dealt with by the body?

Question 70

Describe two important functions of the Golgi apparatus.

Question 71

Briefly describe the glycocalyx and its functions.

Question 72

What factors contribute to the fragility of the lysosome and subsequent cell autolysis?