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Biology 107 POWERPOINT SLIDES > Chapter 5- The Working Cell > Flashcards

Chapter 5- The Working Cell Flashcards

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1
Q

What membrane protein is responsible for allowing water to pass through the cell membrane?

A

Aquaporin

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2
Q

What is aquaporin’s function?

A

To allow the passage of water molecules, water channels

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3
Q

One molecule of _____ allows ______ of _____ to stream through the cellular membrane every _____.

A

Aquaporin
Billion
Water molecules
Second

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4
Q

Aquaporin are common in cells involved in what?

A

Water balance

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5
Q

Give an example of a human organ where aquaporin proteins are vital to the organ’s proper functioning.

A

Kidneys

The kidneys filter and reabsorbs many liters of water per day

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6
Q

Defective aquaporin proteins could lead to what in humans? (Rare cases)

A

An inability of the kidneys to function properly and reabsorb water.

These people, though rare, must drink 20L per day to stay hydrated

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7
Q

Fluid retention during pregnancy is likely caused by what?

A

An increased synthesis of aquaporin proteins

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8
Q

What is the plasma membrane?

A

The boundary that encloses a living cell

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9
Q

The plasma membrane exhibits what traits?

A

Selective permeability

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10
Q

What is selective permeability?

A

Allowing some substance to cross (the plasma membrane) more easily than others

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11
Q

What are the 6 types of protein found in the plasma membrane?

A 
Glycoprotein
Junction protein
Active transport protein
Channel transport protein
Receptor proteins
Attachment proteins
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12
Q

Glycoproteins serve what function in the plasma membrane?

A

Serve as ID tags that are recognized by membrane proteins of other cells

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13
Q

The junction protein serves what function in the plasma membrane?

A

May form intercellular junctions that attach to adjacent cells

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14
Q

What is the function of Active Transport Proteins in the plasma membrane?

A

Allows specific ions or molecules to enter or exit the cell (ATP)

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15
Q

Give an example of a molecule allowed out of the cell through the Active Transport Protein?

A

Solute molecule

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16
Q

What is the plasma membrane composed of?

A

A phospholipid bilayer with protein molecules suspended in it, as well as enzymes and cholesterol.

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17
Q

Phospholipids are the key ingredient of _____?

A

Biological membranes

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18
Q

Phospholipids were probably among the first organic molecules that formed from _____.

A

Chemical reactions on early earth

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19
Q

What would have been a critical step in the evolution of the first cells?

A

The formation of membrane-enclosed collections of molecules.

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20
Q

What is a basic requirement for life for cells?

A

The ability to enclose a successful assembly of molecules

The ability to regulate chemical exchanges with its environment

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21
Q

What are the 4 functions of the plasma membrane?

A
  1. Maintains a high concentration of materials in the cell
  2. Keeps harmful materials out
  3. Control the movement of materials to and from the cell
  4. Let the cell sense its environment
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22
Q

Where are plasma membranes found?

A 
Cell
Nucleus
Vacuoles
Mitochondria
Chloroplasts
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23
Q

The plasma membrane is embedded with what?

A

Proteins

Cholesterol

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24
Q

_____ gives the plasma membrane extra _____.

A

Cholesterol

Strength

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25
Q

What is the structure of the plasma membrane?

A

A lipid bilayer

two sheets of phospholipids, so a phospholipid bilayer

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26
Q

The fluid mosaic model illustrates _____?

A

A patchwork of diverse protein molecules embedded in a phospholipid bilateral, as well as cholesterol.

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27
Q

The plasma membrane exhibits _____ regulating _____.

A

Selective permeability

The cell’s molecular traffic

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28
Q

Molecules have a lot of _____ due to their _____.

A

Thermal energy

Constant motion

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29
Q

What results from the constant motion of molecules?

A

Diffusion

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30
Q

What is diffusion?

A

The tendency of particles of any substance to spread out into available space

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31
Q

What is a permeable membrane?

A

One that allows molecules of certain types/molecules to diffuse through it

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32
Q

What is net movement of diffusion of molecules across a membrane?

A

Movement of molecules from the concentrated side of the membrane to the other, less concentrated, side.

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33
Q

When molecules (dye) diffuse across a membrane, they are _____ their _____.

A

Decreasing

Concentration gradient

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34
Q

What is equilibrium of diffusing molecules across a membrane?

A

When the concentration of molecules on both sides of the membrane is equal.

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35
Q

During equilibrium of molecules across a membrane, do molecules still move back and forth?

A

Yes- although there is no net exchange of molecules

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36
Q

What is passive transport?

A

When a cell doesn’t have to do work to diffuse molecules across its membrane

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37
Q

Diffusion down concentration gradients is responsible for what in regards to cellular respiration?

A

Allows 02 in (necessary for cellular respiration)

Allows CO2 and metabolic waste out

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38
Q

02 and CO2 are small, _____ molecules that _____ easily across _____.

A

Non-polar
Diffuse
The phospholipid bilayer of a membrane

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39
Q

Can ions and polar molecules also diffuse across the hydrophobic interior of a membrane?

A

Yes

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40
Q

How can ions and polar molecules cross the phospholipid bilayer of membranes?

A
  • Must have Transport proteins to help them cross the membrane
  • Must be moving down their concentration gradient
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41
Q

What 4 functions do proteins provide for membrane function?

A

Structural support
Recognition
Communication
Transport

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42
Q

The cell membrane separates what?

A

The cell from its environment

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43
Q

What are 4 factors that determine permeability?

A

Lipid solubility
Molecular size
Polarity
Charge

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44
Q

What can move across the plasma membrane through diffusion?

A

Gases (O2 and CO2)
Small non-polar molecules
H2O

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45
Q

Solutes (molecules and ions) cannot _____.

A

Cross is phospholipid bilayer on their own

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46
Q

What are the 3 forms of transport across the membrane?

A

Passive transportation

 1. simple diffusion
 2. facilitated diffusion

Active transport

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47
Q

What is simple diffusion?

A

Materials move DOWN their concentration gradient through the phospholipid bilayer

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48
Q

What is facilitated diffusion?

A

The passage of materials is aided on both sides by a concentration gradient and by a transport protein

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49
Q

What is active transport?

A

Molecules move through a transport protein

Energy is expended (ATP) to move the molecules against their concentration gradient

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50
Q

Give an example of simple diffusion.

A

Oxygen diffusing into a cell

Carbon dioxide diffusing out of a cell

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51
Q

Give an example of facilitated diffusion.

A

Glucose or amino acids moving from blood into a cell

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52
Q

Give an example of active transport.

A

Pumping Sodium (Na+ ions) out of the cell and Potassium (K+ ions) into the cell against strong concentration gradients.

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53
Q

What is osmosis?

A

Diffusion of water across a selectively permeable membrane

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54
Q

A solute is a substance that dissolved in _____.

A

A liquid solvent

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55
Q

The resulting mixture of a solute and solvent is called a _____.

A

Solution

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56
Q

What is tonicity?

A

The ability of a surrounding solution to cause a cell to gain or lose water.

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57
Q

The tonicity of a solution depends on what?

A

The solution’s concentration of solutes relative to the concentration of solutes inside the cell

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58
Q

What is an isotonic solution?

A

A solution that causes no diffusion of molecules across the membrane of a cell

The cell gains water at the same rate it loses

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59
Q

Intravenous solutions must be _____ to the _____ cells.

A

Isotonic

Blood

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60
Q

Extracellular fluid in most animal body cells is _____ to the cell.

A

Isotonic

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61
Q

Seawater is ______ to the cell’s of _____.

A

Many marine animals

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62
Q

What is a hypotonic solution?

A

A solution with a lower solute concentration that that of the cell

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63
Q

What is an isotonic solution?

A

A solution where the solute concentration is equal to that of the cell

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64
Q

What may occur to cells placed in a hypotonic solution?

A

The cell gains water, swells, and bursts

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65
Q

Lyse means _____.

A

Burst

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66
Q

Hypo means _____.

A

Below

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67
Q

Hyper means _____.

A

Above

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68
Q

What is a hypertonic solution?

A

A solution in which the solute concentration is more than that of the cell.

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69
Q

What may occur to cells placed in a hypertonic solution?

A

They will lose their water causing them to shrivel and die.

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70
Q

What is osmoregulation?

A

The homeostatic maintenance of solute concentration and water balance by a cell or organism

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71
Q

Essentially, osmoregulation is

A

Regulating water balance

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72
Q

What is turgor pressure?

A

The back pressure exerted by a cell wall as water enters and swells inside the plant cell

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73
Q

Turgor pressur prevents what?

A

Prevents the plant cell from taking in too much water and bursting

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74
Q

Non-woody plants depend upon _____ for _____.

A

Turgor pressure

Mechanical support

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75
Q

What occurs to plant cells subjected to an isotonic solution?

A

There is no net movement of water into the cells

The plant is limp and may wilt.

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76
Q

When a plant cell is placed in a hypotonic solution, the plant cells become _____.

A

The cell will gain water, but not too much due to turgid pressure

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77
Q

What is a healthy solution for plant cells?

A

A hypotonic solution

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78
Q

What occurs to plant cells in a hypertonic solution?

A

Through plasmolysis, the plant will wilt and can be lethal to plant cells and the plant

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79
Q

Bacteria and fungi also _____ in _____ solutions.

A

Plasmolyze

Hypertonic

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80
Q

Why can meat and other foods be preserved in concentrated salt solutions?

A

Because the salt concentration causes bacteria and fungi to plasmolyze and die.

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81
Q

What is plasmolysis?

A

The process in which a plant cell loses water causing shriveling.

The plasma membrane separates from the cell wall

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82
Q

What is a product of plasmolysis?

A

Wilting of the plant

Death

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83
Q

Hydrophilic molecules and ions require the help of _____ to move across a membrane.

A

Specific transport proteins

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84
Q

Why is facilitated transport a passive transport?

A

Because no energy is required to move hydrophilic molecules and ions through a transport protein.

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85
Q

What is the driving force in passive transport?

A

Concentration gradient

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86
Q

What does a carrier protein do?

A

It binds to a molecule
Changes its shape
Releases the molecule on the other side of the membrane

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87
Q

A carrier protein is a _____ protein.

A

Transport

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88
Q

What is the function of transport proteins?

A

Helps a specific substance diffuse across the membrane down its concentration gradient, requiring no energy expenditure.

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89
Q

What are four substances that use facilitated diffusion to cross cell membranes?

A

Sugars
Amino acids
Ions
Water

90
Q

Why does water not diffuse quickly through a membrane via simple diffusion?

A

Because water is polar and this will not move quickly through the hydrophobic interior of the lipid bilayer.

91
Q

Certain cells may need quicker access to water than other cells. What gives cells greater access to water?

A

More aquaporin (a protein channel)

92
Q

Transport proteins are specific as to _____.

A

The solutes they transport

93
Q

Because aquaporin proteins are selective to the solute the help diffuse, what does that mean for the cell membrane?

A

The membrane’s selective permeability is related to the specific aquaporin proteins embedded and their specific solute of transport.

94
Q

Where have aquaporins been found?

A

Animals, plants, and bacteria

95
Q

In active transport, a cell must _____ to move ______.

A

Expend energy

A solute against its concentration gradient

96
Q

What energy molecules is used in most active transport?

A

ATP

97
Q

Active transport allows cells to _____.

A

Maintain internal concentrations of molecules and ions that are different from concentrations in its surroundings.

98
Q

What are the three processes a transport protein must undergo?

A
  1. Bind to the solute
  2. ATP provides energy for change in protein shape to allow solute to be released on other side of membrane.
  3. The protein returns to its natural conformation
99
Q

What is exocytosis?

A

The process by which bulky materials are exported from a cell

100
Q

What are the steps of the cellular process of exocytosis?

A
  1. Transport vesicles buds from the Golgi Apparatus

2. The vesicle moves to and merges with the plasma membrane, releasing its contents outside of the cell

101
Q

What is endocytosis?

A

A transport process through which a cell takes in large molecules or droplets of fluid

102
Q

What are to two types of endocytosis?

A

Phagocytosis

Receptor-mediated endocytosis

103
Q

Phagocytosis is also known as “____”.

A

Cellular eating

104
Q

What are pseudopodia (pseudopodium)

A

Extensions of the cell used to grab large molecules and wrap them inside a vacuole

105
Q

What occurs during phagocytosis?

A
  1. The psuedopodium wrap around a molecule
  2. The molecule is enclosed inside a membrane-enclosed sac, a vacuole
  3. The vacuole then fused with a lysosome
  4. The hydrolytic enzymes within the lysosome digest the contents of the vacuole
106
Q

What does receptor-mediated endocytosis enable a cell to do?

A

Allows it to acquire specific solutes

107
Q

How does receptor-mediated endocytosis work?

A
  1. Receptor proteins for specific molecules, embedded in specific regions of the membrane, are lined by a layer of coat proteins.
  2. The plasma membrane indents to form a protein lined cavity
  3. Receptor proteins in the cavity pick up particular molecules from extracellular fluid
  4. The coated cavity punches closed to form a vesicle
  5. The vesicle the releases the contents into the cell’s cytoplasm
108
Q

Human cells use what type of endocytosis to take in cholesterol for membrane synthesis?

A

Receptor-mediated endocytosis

109
Q

Cholesterol circulates in the blood in particles called ____.

A

LDL’s

Low Density Lipoproteins

110
Q

What is hypercholesterolemia?

A

LDL receptor proteins are defective or missing

Cholesterol accumulates to high levels in the blood leading to atherosclerosis

111
Q

What is atherosclerosis?

A

The buildup of fatty deposits in the walls of blood vessels

112
Q

What is tonicity?

A

Relative concentrations of solutes in two fluids separates by a selectively permeable membrane

113
Q

Tonicity determines _____.

A

Movement of water

114
Q

What is energy?

A

The capacity to cause change, to do work

115
Q

How many basic forms of energy are there?

What are they?

A

2
Kinetic
Potential

116
Q

What are the two basic forms of energy?

A

Kinetic

Potential

117
Q

What type of energy is thermal energy?

A

Kinetic

118
Q

Kinetic energy is the energy of ______.

A

Motion

119
Q

Thermal energy is a type of kinetic energy associated with what?

A

Associated with the random movements of atoms or molecules

120
Q

When transferred, thermal energy transfers as what?

A

Heat

121
Q

Heat is _____.

A

Kinetic energy

122
Q

What is potential energy?

A

Energy that matter possesses because of its location or structure (stored energy)

123
Q

What is chemical energy?

A

Potential energy available for release as a chemical reaction

124
Q

What are examples of potential energy?

A

Water behind a dam

On a bike at the top of a hill

125
Q

Chemical energy is the energy that can be transformed to _____.

A

Power the work of the cell

126
Q

Molecules possess _____ energy because of the arrangement of ______ between their _____.

A

Potential
Electrons in the bonds
Atoms

127
Q

Why do molecules possess potential energy?

A

Because of the arrangement of electrons in the bonds between atoms

128
Q

What is thermodynamics?

A

The study of energy transformations that occur in a collection of matter.

129
Q

The First Law of Thermodynamics is also known as _____.

A

The Law of Energy Conservation.

130
Q

What does the 1st Law of Thermodynamics state?

A

Energy inthe universe is constant. Energy can be transferred and transformed, but it cannot be created or destroyed

131
Q

What is entropy?

A

A measure of disorder or randomness

132
Q

The greater the entropy, _____.

A

The more randomly arranged a collection of matter is.

133
Q

What is the Second Law of Thermodynamics?

A

Every energy conversion increases the entropy (disorder) of the universe

134
Q

How much of gasoline is actually used as kinetic energy to move a car?

A

About 25%

135
Q

What % of gasoline is as heat?

A

About 75%

136
Q

What occurs during cellular respiration?

A

The chemical energy stored in organic molecules is used to produce ATP, which the cell’s use to perform work.

137
Q

What are the waste products of human cells and gasoline?

A

Carbon Dioxide (CO2) and water (H2O)

138
Q

What percentage of its fuel does the body use for cellular work?

A

About 34%

139
Q

How much of a cell’s energy is lost as heat?

A

About 66%

140
Q

Why does exercise make you warm?

A

Because most of the cells’ energy is lost as heat energy (66%)

141
Q

What are the two types of chemical reactions?

A

Exergonic reaction

Endergonic reaction

142
Q

What is an exergonic reaction?

A

A chemical reaction that releases energy

143
Q

What does “exergonic” mean?

A

Energy outward

144
Q

How does an exergonic reaction work?

A

It begins with reactants whose covalent bonds contain more potential energy than those in the products.

The reaction releases to the surroundings an amount of energy equal to the difference in potential energy between reactants and products (see pg. 85)

145
Q

An Exergonic reaction _____ to the surroundings _____ ,equal to _____.

A

Releases
Energy
Difference in potential energy between reactants and product

146
Q

Endergonic reactions require _____.

A

A net input of energy

147
Q

Endergonic reactions yield _____.

A

Products that are rich in potential energy

148
Q

Endergonic reactions begins with _____.

A

Reactants that contain relatively little potential energy

149
Q

What occurs during the reaction phase of an endergonic reaction?
The products have _____ than the _____.

A

Energy is absorbed from the surrounds
MORE chemical energy
Reactants

150
Q

Photosynthesis is an example of an _____.

A

Endergonic process

151
Q

During photosynthesis, plants use _____ (CO2 and H2O) with energy absorbed from _____ producing _____.

A

Energy poor reactants
Sunlight
Energy rich sugar molecules

152
Q

Living cells carry out _____ of ______.

A

Thousands

Exergonic and endergonic reactions

153
Q

A total of an organisms chemical reactions is called _____.

A

Metabolism

154
Q

What is a metabolic pathway?

A

A series of chemical reactions that either builds a complex molecule or breaks down complex molecules into simpler compounds

155
Q

What is energy coupling?

A

The use of energy released from exergonic reactions to drive endergonic reactions

156
Q

_____ molecules are key to energy coupling.

A

ATP

157
Q

Energy is the capacity _____.

A

To do work

158
Q

In the cell, the energy from an _____ of ATP hydrolysis can be used to fuel an _____.

A

Exergonic reaction

Endergonic reaction

159
Q

ATP synthesis is an _____ reaction.

A

Endergonic

160
Q

Energy from cellular respiration is an _____ reaction

A

Exergonic

161
Q

ATP hydrolysis is an _____ reaction.

A

Exergonic

162
Q

Energy energy created for cellular work is an _____ reaction.

A

Endergonic

163
Q

An ATP molecule consists of what molecular structure?

A

An organic molecule called Adenosine

A troposphere tail of three phosphate groups

164
Q

The phosphate groups of ATP are _____ charged.

A

Negatively

165
Q

The bonds connecting phosphate groups of ATP are _____ and can be easily _____ through _____.

A

Unstable
Broken
Hydrolysis

166
Q

Hydrolysis of ATP is _____ because _____.

A

Exergonic

Releases energy

167
Q

What is phosphorylation?

A

The phosphate group transfer from ATP to another molecule

168
Q

_____ depends on ATP energizing molecules by _____.

A

Cellular work

Phosphorylating them

169
Q

What 3 types of work does a cell perform that is fueled by ATP?

A

Chemical work
Transport work
Mechanical work

170
Q

How is ATP used is chemical work?

A

Phosphorylation of reactants provides energy to drive the endergonic synthesis of products

171
Q

How is ATP used in transport work?

A

ATP drives the Active Transport of solutes across a membrane against their concentration gradients by phosphorylating transport proteins.

172
Q

How is ATP used in mechanical work?

A

The hydrolysis of ATP when attached to special muscle motor proteins in muscles cells causes the proteins to change shape and pull on other protein filaments, cause the cell to contract

173
Q

ATP is a _____ resource.

A

Renewable

174
Q

Enzymes do what?

A

Speed up metabolic (chemical) reactions by lowering energy barriers

175
Q

Before a chemical reaction may begin, what must be overcome

A

The energy barrier

176
Q

What is activation energy?

A

Energy that is absorbed to contort or weaken bonds in reactant molecules so they can break and new bonds can form

177
Q

Why is it called activation energy?

A

Because it activates the reactants

178
Q

The activated energy barrier prevents what?

A

The highly ordered molecules of cells from spontaneously breaking down

179
Q

Heat _____ reactions.

A

Speeds up

180
Q

How does heat speed up reactions?

A

It speeds up molecules

Agitated atoms so bonds break more easily and reaction can occur

181
Q

Heating a cell would speed all _____.

A

Chemical reactions

182
Q

Too much heat can _____ the cell.

A

Kill

183
Q

Enzymes function as _____ increasing the _____ without being _____.

A

Biological catalysts
Rate of reaction
Consumed by the reaction

184
Q

Almost all enzymes are _____.

A

Proteins

185
Q

Some RNA molecules function as _____.

A

Enzymes

186
Q

How does an enzyme speed up a reaction?

A

By lowering the activation energy need for a reaction to begin

187
Q

The _____ between reactants and _____ is _____ for ______.

A

Change
Products
The same as enzyme catalyze and non-catalyze reactions

188
Q

A lowered activation energy level allows an ______ to ______.

A

Enzyme-catalyze reaction

Occur quicker

189
Q

Each cellular reaction is catalyze by _____.

A

A specific enzyme

190
Q

Without an enzyme, the ______ May never be breached.

A

Energy activation level

191
Q

An enzyme is _____ in the ______ it _____.

A

Selective
Reaction
Catalayzes

192
Q

What is an enzymes substrate?

A

The specific reactant an enzyme acts on

193
Q

What is an “active site”

A

The region of an enzyme where the substrate is located

Typically a pocket or groove on the surface of the enzyme

194
Q

Why are enzymes very specific?

A

Because only specific substrate molecules fit into their active sites

195
Q

What are the 4 steps in the catalytic cycle of an enzyme?

A
  1. Enzyme starts with empty active site
  2. The substrate enters active site, which enfolds the substrate with an induced fit
  3. The substrate is converted into products
  4. The products are released
196
Q

What is the induced fit? Of enzymes

A

The active site changes shape, embracing the substrate snugly

197
Q

In reactions involving two or more reactants, the active site does what?

A

Holds the substrate in the proper orientation for a reaction to occur

198
Q

How many molecules may a single enzyme act upon per minute?

A

Thousands or millions of substrate molecules

199
Q

Higher temperatures do what to enzymes?

A

Denature them

200
Q

What range of temps do most enzymes within the human body thrive?

A

35-40 Celsius (95-104 Fahrenheit)

201
Q

Prokaryotes that live near hot springs have an optimal enzyme temperature of _____.

A

70 Celsius (158 Fahrenheit)

202
Q

The optimal pH for enzymes is ______.

A

Near neutrality, 6-8 pH

203
Q

What is a pepsin?

A

A digestive enzyme in your stomach

204
Q

Pepsin works best in a pH of _____.

A

2

205
Q

Most enzymes require help from _____.

A

Cofactors

206
Q

What are cofactors?

A

Nonprotein helpers which bind to the active site and function in catalysis

207
Q

Most cofactors are _____.

A

Inorganic

208
Q

What is a coenzyme?

A

An organic molecule cofactor

209
Q

A cofactor that is an organic molecule is called _____.

A

A coenzyme

210
Q

Most vitamins in nutrition function as _____.

A

Coenzymes

211
Q

A cell must control ____ it’s various enzymes are _____.

A

When and where

Active

212
Q

What are two ways the cell can regulate enzymes?

A
  1. Switching on/off the genes that encode specific enzymes

2. Regulating the activity of enzymes once created

213
Q

What is an inhibitor?

A

A chemical that interferes with an enzyme’s activity

214
Q

Some _____ resemble the enzyme’s _____ and compete for _____.

A

Inhibitors
Normal substrate
Entry into the active site

215
Q

What is a competitive inhibitor?

A

An inhibitor that reduces an enzymes productivity by blocking substrate molecules from entering the active site

216
Q

How can competitive inhibitors be overcome?

A

Increasing the concentration of substrate

217
Q

A non competitive inhibitor does not _____.

A

Enter the active site

218
Q

What does a non competitive inhibitor do?

A

It binds to the protein other than at the active site

This binding changes the enzyme shape so it’s active site can no longer fit it’s substrate

219
Q

Cells use inhibitors as _____.

A

Important regulators of cellular metabolism

220
Q

What is feedback inhibition?

A

When a cell produces more of a product than necessary, that product may act as an inhibitor to one of the enzymes early in the pathway

221
Q

Inhibition can be reversed when _____.

A

When weak chemical reactions bind inhibitor to enzyme

222
Q

When are inhibitions not reversible?

A

If the inhibitor binds to the enzyme with covalent bonds

Biology 107 POWERPOINT SLIDES (9 decks)

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