Bio Lec Exam 2 Flashcards

(157 cards)

1
Q

1

A

FALSE

The inner membrane of mitochondria is folded into cristae. Chloroplasts have thylakoid membranes.

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2
Q

2

A

2) FALSE

All cells have a plasma membrane that
regulates the passage of molecules into and
out of the cell. Animal cells do not have a
cell wall.

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3
Q

3

A

3) TRUE

It is true that mitochondria are thought to be
derived from aerobic bacteria that became
part of the eukaryotic cell through
endosymbiosis.

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4
Q

4

A

4) TRUE

It is true that mitochondria and chloroplasts
are able to reproduce independently from the
division of the cell.

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5
Q

5

A

5) TRUE

It is true that receptor-mediated endocytosis
involves the use of specific proteins in the
cell membrane.

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6
Q

6

A

6) FALSE

It is true that the fluidity of a membrane
increases as the percentage of unsaturated
fatty acids in the phospholipids goes up. As
the percentage of unsaturated fatty acids
goes down, the membrane become less fluid

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7
Q

7

A

False

In the cells that line the lumen of the small
intestine, it is tight junctions, not gap
junctions that keep materials in the digestive
tract from slipping between the cells and
entering the tissues.

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8
Q

8

A

8) FALSE

In the sodium-potassium pump, sodium is
transported out of the cell and potassium is
transported into the cell using ATP energy.

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9
Q

9

A

9) FALSE

The process by which a white blood cell or
an amoeba engulfs bacteria is called
phagocytosis. Pinocytosis is “cell drinking”
and instead of solid particles, the cell
engulfs small droplets of liquid or very tiny
particles.

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10
Q

10

A

10) TRUE

It is true that an extracellular matrix helps
some cells to adhere to neighboring cells.

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11
Q

11

A

11) TRUE

If a change in pH alters an allosteric site
where an inhibitor binds, but doesn’t change
the active site for the intended substrate, it
would be possible for an enzymatically
controlled reaction to occur as normal. This
is a true statement.

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12
Q

12

A

12) TRUE

In order to roll a rock down a hillside, you
must first push it up the hill. It is true that
pushing the rock is analogous to the energy
of activation of a chemical reaction

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13
Q

13

A

True

Enzyme inhibition is the process that turns
off an early enzyme in a metabolic pathway.
This can occur when the product of the
pathway acts as an inhibitor. This is a true
statement.

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14
Q

14

A

14) FALSE

This is a false statement. Enzymes are
proteins that speed up chemical reactions.

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15
Q

15

A

15) [A, C, D]

Bacterial cells have a cell wall, a cell
membrane, and ribosomes (along with
cytosol) but do not have any membrane-
bound organelles such as a nucleus or a
Golgi apparatus.

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16
Q

16

A

16) [A, B, C]

Eukaryotic cells in general will not be
affected by penicillin. Animal cells do not
have a cell wall and plant cell walls are
constructed differently from bacterial cell
walls. It is also true that bacteria that have
already formed their cell walls would be
unaffected and that penicillin would stop the
growth of active colonies of susceptible
bacteria.

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17
Q

17

A

17) [A, B, C]

The bacteria cell wall is located outside the
cell membrane. There may or may not be
fimbriae present on the outside of the cell.
Inside the cell there may be plasmids and
DNA, but the DNA is not separated from the
rest of the cell by a membrane. The
glycocalyx, which has a protective function,
lies outside of the cell membrane

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18
Q

18

A

A, B, D

Microtubules are important for maintaining
cell shape, for moving chromosomes during
cell division and for moving materials across
the surface of respiratory cells. Microtubules
do not play a role in the breakdown of fatty
acids and lipids. That is accomplished by the
peroxisome.

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19
Q

19

A

19) [C, D, E]

Plant cells and prokaryotic cells have a cell
wall. Animal cells do not. The functions of
the cell wall are to shape, support, and
protect the cell.

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20
Q

20

A

20) [A, C]

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21
Q

21

A

21) [A, B, C, D]

The major functions of the plasma
membrane include everything but the
production of proteins used in construction
of the cell wall.

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22
Q

22

A

22) [A, D, E]

The extracellular matrix can help cells
adhere to neighboring cells, and can be
made of collagen and elastin. It influences
the activities of the cytoskeleton and,
therefore, the shape and activities of a cell.

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23
Q

23

A

23) [C, D, E]

The binding of a chemical messenger to a
membrane receptor usually initiates a
cascade of reactions called the signal
transduction pathway which can cause
changes in the shape or movement of a cell
or the activation of an enzyme. The
chemical messenger may also affect
activities in the nucleus. For example, it can
cause a gene to be activated.

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24
Q

24

A

24) [B, D, E]

Cyclic AMP and calcium ions are common
second messengers. Cyclic AMP usually
activates an enzyme in a second messenger
system. Second messenger systems usually
amplify the cellular response to a chemical
messenger.

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25
25
25) [A, D] If a change in pH alters the allosteric site where an inhibitor binds, the enzyme's activity would not be affected but the inhibitor would no longer decrease the activity of the enzyme.
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26) D Only autotrophic eukaryotic cells contain chloroplasts. Heterotrophic and autotrophic cells have mitochondria.
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27) D The rough ER and the smooth ER both transport molecules to other parts of the cell via vesicles. One of the many functions of the cytoskeleton is to move organelles around the cell. Ribosomes do not assist in the movement of materials throughout the cell.
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28) E After being formed by the ribosomes located on the endoplasmic reticulum, proteins are transported to the Golgi in vesicles. Vesicles are also used to ship proteins out of the Golgi
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D The cell theory states that all cells come from preexisting cells and therefore it does not state that bacteria and other small organisms can arise spontaneously. All other choices are correct.
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30) C In light of the cell theory that "all living things are composed of cells," the general concept still holds because these organisms are cellular at specific stages in their life cycle.
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31) C Golgi apparatus give rise to both lysosomes and vesicles.
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32) D Cells are the smallest unit of life.
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33) A The nucleoid region is unique to bacterial cells.
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34) A
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35) B The cell wall would function to provide a rigid wall that prevents the cell from swelling.
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36) C
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37) A It is believed that both mitochondria and chloroplasts were engulfed by larger eukaryotic cells.
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38) C
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39) C
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40) B Chloroplasts are to photosynthesis as mitochondria are to aerobic respiration
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D Proteins are synthesized by ribosomes and lipids are made in the smooth endoplasmic reticulum.
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42) B Without a cytoskeleton, eukaryotic cells would not have an efficient way to transport materials from one organelle to another.
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43) A
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44) E Membrane-bounded vesicles that break down fatty acids while producing hydrogen peroxide as a waste product are peroxisomes.
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45) C Mitochondria have a double membrane.
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46) C
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47) D The cells that line our respiratory tract, and one-celled paramecia both have short hair like projections called cilia.
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48) C The Golgi is responsible for packaging up materials received from the ER and assisting in their secretion from the cell.
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49) B The most likely explanation for the bad taste of meat that has "freezer burn" from repeated freezing is the destruction of lysosomes and resultant autodigestion
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C Golgi apparatus give rise to both lysosomes and vesicles.
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51) D All cells have these two characteristics: a plasma membrane and ribosomes in the cytoplasm.
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52) B This leads us to conclude that most cell components are constantly broken down and rebuilt.
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53) A Adequate surface area (plasma membrane) is needed to furnish nutrients to and expel wastes from the volume (cytoplasm).
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54) D The plant cell's central vacuole provides the plant cell with support, stores nutrients and cellular waste products, and is a reservoir for water. All of the choices are correct.
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55) C The only structure NOT associated with mitochondria is stroma. Stroma is found in chloroplasts.
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56) C Multicellular organisms are composed of a variety of different cell types.
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57) B The ribosome synthesizes proteins based on the information it receives in an mRNA molecule.
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58) D All are correct except that the ribosomes do not carry out cellular respiration.
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59) A The nucleus is the most prominent cellular structure.
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60) A Protein synthesis begins when mRNA makes a copy of a gene and carries that copy out of the nucleus to a ribosome located in the cytoplasm.
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61) B The nuclear envelope contains pores which allow the mRNA to exit the nucleus.
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62) B Vesicles from the Golgi apparatus are made of the same phospholipid structure as the cell membrane, therefore the vesicles are able to easily fuse with the cell membrane.
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63) D The peroxisomes are responsible for breaking down lipids within the cell.
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64) D ATP is generally not stored in vacuoles.
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65) A Actin filaments are found in the cell membrane of amoebas that help facilitate movement.
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66) B The motor molecule myosin is responsible for pulling the actin filament along
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C The inner membrane system of the mitochondria is called the cristae.
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68) D Cholesterol is lipid in nature and a steroid. It regulates the fluidity of animal cell membranes. Integral proteins do not serve this function.
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69) C Both of these answer choices are correct. Proteins in a membrane are peripheral if they are on the inside surface and held in place by the cytoskeleton. Integral proteins are embedded in the membrane and may protrude through either surface of the bilayer.
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70) C
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71) A
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72) B The newly discovered membrane channel protein that accounts for the quick movement of water across a membrane is called an aquaporin.
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73) C
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74) E
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75) D
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76) E
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77) B
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78) C The blood type proteins are located on the outer surface of the red blood cell membrane.
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E Whether a molecule can cross the plasma membrane depends upon the size of the molecule, the shape of the molecule, the chemical properties of the molecule, and the charge of the molecule. The number of double bonds in the molecule does not affect its ability to cross a membrane.
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80) B A glass of water is hypotonic to the celery cells because it has a lower concentration of solute than the celery cells. In this solution, water will move into the celery cells from the surrounding solution.
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81) B Osmosis is the movement of water across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration.
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82) D The sequence of the mitochondrial DNA in the cell to be transplanted would not affect its ability to be transplanted. The cell recognition proteins, major histocompatibility complex proteins, and carbohydrate chains in the membranes of the cells in the tissues to be transplanted all effect the ability of the tissues to be transplanted.
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83) A Since the interior of the cell is hydrophobic, polar molecules and ions cannot readily pass through the membrane. Many of these molecules and ions will require both energy and transport proteins to move in and out of the cell
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84) E Freshwater protozoans react to a hypotonic environment by removing water through a contractile vacuole.
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85) B
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86) E Cells change their chemical identity on a regular basis by producing different glycolipids and glycoproteins internally and moving them into the plasma membrane.
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87) B Plants show turgor pressure when their cells contain water vacuoles that are full of water.
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88) E Active transport is the movement of a substance against its concentration through the release of energy from ATP.
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89) A Sugars and amino acids are carried into the cell by means of facilitated transport.
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90) D The process by which cholesterol is transported into the cell by binding of LDL to its receptor and the internalization of the receptor-LDL complex is by receptor- mediated endocytosis.
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91) A The solution in the tube has a higher concentration of solute than the solution in the beaker. It is, therefore, hypertonic.
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92) B The highest concentration of water is in the 5% solution (95% water, 5% solute).
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93) C As diffusion occurs, the 10% solution will become less concentrated and the 5% solution will become more concentrated.
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94) A The process should be identified as facilitated transport because of the movement of solute from a higher to lower concentration through a carrier protein.
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95) C In an isotonic environment, there would be no net movement of water.
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96) E Plasma membranes of eukaryotic cells DO NOT contain pores that allow materials to pass freely through the membrane. Such pores would prevent the cell from being able to maintain homeostasis.
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97) D Collagen provides the cell with the ability to resist stretching.
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98) B The cell membrane would have to include a proton pump to rid the cytoplasm of excess protons, thus increasing the pH.
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99) D If a living plant were moved from a freshwater aquarium to a saltwater aquarium, the plant's cells would lose water and plasmolysis would occur
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D The reason plants wilt if they are watered with a salt solution is due to loss of water and the resulting decrease in turgor pressure.
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101) A Active transport is used to move ions against a concentration gradient.
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102) C Active transport requires large amounts of energy. If the mitochondria cease to function the active transport in the kidneys would decrease.
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103) B Preventing the mixing of cellular contents during endocytosis is worth the energy expended.
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104) B Endocytosis, pinocytosis, and receptor- mediated endocytosis are processes that draw substances into the cell. Cellular wastes would be removed from the cell through the process of exocytosis.
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105) D
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106) C
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107) A
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108) D Animal cells do not contain plasmodesmata. Plasmodesmata are found between plant cells.
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109) A
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110) A
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111) B The process by which a white blood cell or an amoeba engulfs bacteria is called phagocytosis.
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112) C Each cell has a number of different plasma membrane receptors, each of which can bind a specific chemical messenger. Different cell types have different plasma membrane receptors and therefore are only affected by certain chemical messengers.
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113) B Endocrine cell signals are hormones produced by one organ or tissue of the body to influence the function of another organ or tissue.
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114) E All of the biochemical pathways in a cell constitute metabolism.
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115) B Mitochondria and chloroplasts are involved in a redox cycle. Carbon dioxide is reduced during photosynthesis and the resulting carbohydrate is oxidized during cellular respiration.
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116) D All of these factors might increase the activity of an enzyme except the presence of other enzymes.
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117) A
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118) B The first law of thermodynamics states that energy is not created nor destroyed, but it can change from one energy form to another.
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119) D The second law states that some useful energy is lost as heat whenever an energy transfer occurs.
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120) D When an organism dies, the chemical compounds in their cells lose their organization over time because there is no longer an input of energy to maintain the organized state.
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121) C Endergonic reactions can only occur if there is an input of energy.
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122) B The statement that is NOT a consequence of the second law of thermodynamics is: Reactions that occur spontaneously are those that increase the amount of useful energy in a system.
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123) B Coupling occurs when the energy released by an exergonic reaction is used to drive an endergonic reaction.
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124) A The subunits from which ATP is made are ADP and phosphate.
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125) C ATP is considered to be a molecule that carries a great deal of chemical energy in a chemical bond.
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126) D ATP is considered a high-energy compound because under cellular conditions, 7.3 kcal per mole of energy is released when a bond is broken between the adenosine diphosphate and the third phosphate.
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127) D The currently accepted theory of how an enzyme and its substrate fit together is the induced fit model: As the substrate binds to the enzyme, the shape of the active site changes to accommodate the reaction.
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128) D It is not true that an enzyme's activity is generally reduced by an increase in substrate concentration. Enzyme activity will increase as substrate concentration increases, until the maximum rate is reached.
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129) E Competitive inhibitors act by binding to the enzyme's active site to that the substrate(s) cannot. Competitive inhibitors do not denature the enzyme.
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130) C A coenzyme is a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
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131) C A muscle contracting is a form of kinetic energy, not potential energy
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132) D In coupled reactions an exergonic reaction releases energy, often captured in the form of ATP, that is then used to power an endergonic reaction.
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133) D Strong acids and bases, and temperatures above 100o C will denature a protein. A missing coenzyme would slow or stop an enzyme but would not denature it.
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134) D
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135) B This is illustrative of the second law of thermodynamics.
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136) C Eventually, sunlight that is absorbed on the earth returns to space as dispersed heat.
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137) A The cellular energy expended in "thinking" must be less than the chemical bond energy supplied in food to these brain cells, since entropy increases with every energy transformation.
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138) A Compared with conditions today, the entropy of the universe then will have greatly increased.
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139) B The reaction would continue since there is plenty of substrate. The reaction would also speed up since room temperature is warmer than the refrigerator.
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140) E If there are twelve different intermediate products produced in the stages for production of a molecule in a cell, we can expect that there are about twelve enzymes, at least one responsible for each step in the metabolic pathway.
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141) E Both taking lactase enzyme and avoiding all dairy products would be correct.
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142) D NAD is oxidized while NADH is reduced.
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143) C The letter "A" depicts the energy of activation.
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144) C The letter "B" depicts the energy of the reactants, while "C" depicts the energy of the products.
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145) A The reaction in the graph is exergonic because the end product has less energy than the reactant.
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146) D The metabolic pathway involves four possible chemical reactions.
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147) A A is the first reactant (substrate) of this metabolic pathway and E is the end product of the pathway.
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148) B ADP → ATP is endergonic and B → C is exergonic.
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149) A C → D on the pathway is an endergonic reaction, which is coupled with the exergonic reaction, ATP → ADP.
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150) A Glucose and oxygen are required substrates for cellular respiration.
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151) A Glucose and oxygen are the end products of photosynthesis.
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152) A The missing substrate is 6H2O.
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153) D All of these are examples of potential energy.
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154) A The rest of the energy is converted into heat.
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155) A
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156) A Potential energy is stored energy, which is then converted into kinetic energy.
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157) D If somehow scientists and engineers created an engine that converts 100% of the energy present in diesel fuel into moving a truck down the road that would NOT be consistent with the 2nd Law of Thermodynamics.