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Principles Of Biology > Practice Problems (Exam 1) > Flashcards

Practice Problems (Exam 1) Flashcards

1
Q

Hydrophilic molecules’ affinity for water occurs because…

A

water is a polar molecule with slight positive and negative charges on opposite sides

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2
Q

A saturated fat has what feature that an unsaturated fat of the same carbon number does not have?

A

more hydrogen atoms

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3
Q

What two things do biological molecules provide that are essential for metabolism?

A

energy and materials

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4
Q

What 4 things are true of enzymes?

A
  1. if the 3D structure is messed up the function is reduced
  2. typically proteins
  3. function is influence by physical and chemical environment
  4. increase speed of reactions by lowering activation energy
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5
Q

The action of an allosteric activator…

A

allows the cell to control which metabolic reactions take place

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6
Q

What would indicate that facilitated diffusion was taking place?

A

a substance was diffusing much faster than the physical properties of the substance indicated it should

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7
Q

The action of the Na/K/ATPase pump is an example of…

A

active transport

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8
Q

A plant that receives pure water would have cells that are more…

A

turgid

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9
Q

The movement of molecules through a plasma membrane channel protein is always ____.

A

down the molecule’s concentration gradient

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10
Q

Which organelle in the cell consists of 3 layers of membrane, its own circular DNA, and a mechanism for producing ATP?

A

Chloroplasts

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11
Q

What structure in the cell is responsible for endocytosis and exocytosis?

A

Actin

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12
Q

What is one major difference between actin microfilaments and microtubules?

A

Microfilaments are smaller and microtubules are bigger

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13
Q

Eukaryotic organisms include…

A

single celled forms, simple multicellular forms, and complex multicellular forms

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14
Q

What is true about the evolution of complex multicellularity?

A

Complex multicellularity evolved independently at least six different times

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15
Q

Cadherins in animals ___.

A

bind to other cells

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16
Q

_____ is the process of creating ____ cells which can only perform a few types of jobs.

A

differentiation; specialized

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17
Q

What is significant about the structure of unsaturated fatty acids?

A

contain one or more double or triple bonds

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18
Q

What is ATP used for?

A

transferring energy from one reaction to another

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19
Q

If enzymes do not provide energy for a chemical reaction, then how can they reduce the energy required for a reaction to proceed?

A

They hold the substrate in positions that make the substrates more likely to react.

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20
Q

What is true about saturated fatty acids at room temperature?

A

Most likely to form solids

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21
Q

The movement of molecules through a plasma membrane channel protein is always…

A

down the molecule’s chemical gradient

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22
Q

You measure the concentration of a polar molecule inside and outside of a cell. You find that the concentration is high and gradually increasing inside the cell. You also measure that the ATP concentration inside the cell and find that it is dropping. What would be your best hypothesis for the process that is occurring?

A

active transport

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23
Q

GLUT2 is a transmembrane protein that binds in a molecule glucose. After binding glucose, the protein changes its shape and releases glucose on the other side of the membrane. It does not require ATP to function. The direction of glucose transport by GLUT2 depends upon the concentration gradient of glucose. What type of protein is GLUT2?

A

carrier protein

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24
Q

A membrane-bound protein travels from the rough endoplasmic reticulum to the golgi apparatus. How does it travel?

A

in a vesicle

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25
Q

What is one role of the smooth endoplasmic reticulum?

A

Make new lipids

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26
Q

Phospholipids contain…

A

2 fatty acid tails, a glycerol backbone, and a functional phosphate group

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27
Q

In what way does an enzyme help to change the activation energy of a reaction?

A

They allow the reaction to go through a more stable transition state by physically positioning the reactants

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28
Q

What could prevent an enzyme from working properly?

A

When the temperature is much higher than the enzyme’s normal operating range

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29
Q

ATP transfers energy from ___ to ___ reactions.

A

Catabolic; anabolic

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30
Q

Which region of the cell membrane in the image is hydrophobic?

A

the interior of the membrane bilayer

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31
Q

What is the function in the plasma membrane of the molecule illustrated by phospholipids?

A

to stabilize fluidity in the membrane

32
Q

The permeability of sodium through the plasma membrane of a cell is ____.

A

close to 0 when the channels are closed and higher when its channels are open.

33
Q

The concentration of calcium ions (Ca++) inside a cell is typically very low, less than 0.001 mM. The Ca++ concentration outside the cell is 2.5 mM. Which type of membrane molecule would be needed to move Ca++ out of the cell?

A

An ion pump

34
Q

What is an example of simple diffusion?

A

Carbon dioxide using direct diffusion to cross the plasma membrane of a cell.

35
Q

Potassium has a higher concentration in the intracellular space, compared to the extracellular space. There are potassium channels available and open in the plasma membrane. Where will potassium move?

A

From the intracellular space to the extracellular space.

36
Q

A transporter that uses the facilitated diffusion of H+ down its concentration gradient from the outside the cell to inside the cell also transports sulfate in the same direction. What type of transporter is this?

A

Symporter

37
Q

The centrioles of a cell, along with the mitotic spindle that forms cellular reproduction, are composed of what?

A

Microtubules

38
Q

Cadherins, integrins, pectin, and the extracellular matrix are all molecules that primarily perform ____.

A

Cellular adhesion

39
Q

Specialized groups of cells working together to carry out a common job within one body are found in ____.

A

Complex multicellular organisms

40
Q

The monomers of RNA are…

A

Nucleotides

41
Q

You perform an experiment looking at the rates of chemical reactions by examining the breakdown of sucrose. You have two test tubes, each with equal amounts of sucrose added to it. Tube A has enzymes added to it, while Tube B does not. You add an indicator solution that becomes a darker shade of blue as more sucrose is broken down. You carry out the experiment for ten minutes. What is true regarding the experiment?

A

When comparing Tube A to Tube B at the end of the experiment, you will find more sucrose molecules still present in Tube B.

42
Q

Where would you most likely find a transmembrane protein?

A

Spanning across the membrane

43
Q

What 2 things are true of proteins embedded in the plasma membrane?

A
  1. have hydrophobic and hydrophilic areas
  2. can help hydrophilic molecules across the membrane
44
Q

If the concentration of particular molecule are equal on both sides of the membrane, facilitated diffusion will have what kind of effect?

A

It will be ineffective

45
Q

By definition, ____ is the process by which a cell engulfs a large particle of food by using pseudopodia.

A

Phagocytosis

46
Q

What type of membrane transporter would be needed to help a single oxygen molecule diffuse across the plasma membrane of a cell?

A

None. Oxygen does not need help to diffuse across the membrane of a cell.

47
Q

True or false: simple diffusion is always an active process.

A

False

48
Q

True or false: facilitated diffusion is a passive process.

A

True

49
Q

True or false: passive transport always requires protein transporters.

A

False

50
Q

A potassium ion channel would be able to provide what type of transport?

A

Facilitated transport

51
Q

Which of the following is part of the endomembrane system in the cell:
1. plasma membrane
2. golgi apparatus
3. mitochondria
4. chromosomes

A

golgi apparatus

52
Q

Transmembrane proteins in the plasma membrane are initially made by…

A

bound ribosomes

53
Q

The mitochondrion is unique among animal cell organelles because it…

A

contains its own circular chromosomes

54
Q

If both eukaryotes and prokaryotes have unicellular organisms, how can you tell them apart?

A

Prokaryotic cells do not contain an endoplasmic reticulum whereas eukaryotic cells do.

55
Q

What kind of bonds link two carbohydrates together?

A

glycosidic

56
Q

If a glycosidic bond was broken, the reaction would be classified as ____ and would ____ ATP.

A

Catabolic; produce

57
Q

When comparing the curves for uncatalyzed versus enzyme catalyzed reactions, at high substrate concentrations we observe the reaction rate increasing for the uncatalyzed reaction but leveling off for the catalyzed reaction. Why do we see these difference in curve shapes?

A

the presence of more substrate molecules in the uncatalyzed reaction makes it more likely they will bump into each other and the reaction will proceed more quickly

58
Q

Make a statement that would best describe an induced fit.

A

the process by which a substrate binds to an active site and causes a change in the shape of an active site, resulting in a tighter fit between the two

59
Q

Organize the following molecules from fastest to slowest in their ability to cross the lipid bilayer by simple diffusion: CO2, water, sucrose, Cl-

A

CO2 > Water > Sucrose > Cl-

60
Q

True or false: hydrophilic molecules easily pass through the core of the bilayer by simple diffusion.

A

false

61
Q

True or false: lipid bilayers will form spontaneously in water because they are more energetically stable than independent lipids in solution.

A

True

62
Q

Explain why cholesterol decreases the permeability of biological membranes.

A

Cholesterol fits in between the phospholipids and blocks diffusion through the membrane

63
Q

How does permeability relate to the length of hydrocarbon tails in a membrane?

A

The longer the tails, the lower the permeability

64
Q

Where would you most likely find an integral protein?

A

Spanning the cell membrane

65
Q

Based on the location of peripheral proteins in relation to the cell membrane, what type of structure would you predict them to have?

A

Hydrophilic

66
Q

Which of the four macromolecules discussed in class would not be found as part of the cell membrane?

A

Nucleic Acids

67
Q

A red blood cell is placed into water that contains NO SOLUTE. Relative to the water, the interior of the cell is ___, and the cell will ___ as a result of water movement.

A

hypertonic; swell

68
Q

Under what circumstances does membrane transport require energy?

A

whenever solute is moved against its concentration gradient

69
Q

You work in a research lab and were given two different samples with artificial bilayers to study. When comparing samples you observe that in one sample glucose moves much faster across the membrane down its concentration gradient than the other sample. What is the cause of this difference?

A

The bilayer where glucose moves faster has carrier proteins for glucose while the other bilayer does not.

70
Q

True or false: Eukaryotic cells differ from prokaryotic cells in that they have an extensive cytoskeleton that allows for cells to change their shapes.

A

true

71
Q

What is a benefit of having eukaryotic genomes rearranged into linear chromosomes?

A

Eukaryotes could have find control over gene expression

72
Q

You are identifying organelles from an unidentified ground up cell. The organelle you are identifying next takes up CO2 and gives off O2. The organelle is most likely a ___ originated from ___.

A

chloroplast; plant

73
Q

A child has been diagnosed with a disease where excess proteins are not being broken down and removed from the cell interior properly. What component of the cell is defective?

A

lysosome

74
Q

A graduate student is studying a new species of multicellular eukaryote. Which traits might identify organisms as definitively complex multicellular and not simple multicellular?

A

Look for the presence of differentiation in cells

75
Q

Plants use ___ to form the molecular attachments that allow their cells to stick together.

A

Pectins

Principles Of Biology (6 decks)

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