FINAL EXAM Flashcards
(126 cards)
1
Q
The fluid mosaic model of the cell membrane refers to the fact that the phospholipid bilayer is a fluid structure in which molecules move laterally and its a mosaic of
- lipids and proteins
- nucleic acids and proteins
- proteins and carbohydrates
- lipids and nucleic acids
A
lipids and proteins
2
Q
Hydrophilic means ____ and the molecule can or can’t form hydrogen bonds with water
A
water loving
can
3
Q
Hydrophobic means ____ and the molecule can or can’t form hydrogen bonds with water
A
water fearing
can’t
4
Q
Which of the following is not a component of a phospholipid?
- phosphate
- glycerol
- non polar head
- hydrophobic chain of fatty acid
A
non polar head
5
Q
True or false
All cells are surrounded by a plasma membrane
A
true
6
Q
true or false
Animals cells are surrounded by a membrane but plants cells have a cell wall and no membrane
A
false
7
Q
true or false
Eukaryotic cells are surrounded by a membrane but prokaryotes are not
A
false
8
Q
what are the two components to a fatty acid
A
hydrocarbon chain and a carboxyl group
9
Q
what are lipids with double bonds
A
unsaturated
olive oil
10
Q
what are lipids with only single bonds
A
saturated
animal fat
11
Q
what is triacylglycerols
A
glycerol + 3 fatty acid chains
12
Q
define amphipathic
A
having both hydrophilic and hydrophobic parts
13
Q
membranes enclose what?
A
cellular spaces
cytoplasm and organelles
14
Q
membranes are composed of ____ and ____ and together they enclose cells and allow for vital cellular reactions
A
lipids and proteins
15
Q
membrane functions
A
- barrier - separates inside of the cell from the outside
- defines intracellular spaces (allows for specialized functions)
- controls what crosses the membrane (selectively permeable)
16
Q
membrane properties
A
- membranes are dynamic (fluid)
- membranes are composed of phospholipids and proteins and the proteins provide specialized functions
17
Q
what is a plasma membrane
A
a lipid bilayer that surrounds all living cells and regulates the cells interaction with the environment
18
Q
what is the endomembrane system
A
- collection of interconnected organelles surrounded by membranes
- huge! more then 50% of a cells membranes are part of the emdomembrane system
- endoplaspic reticulum, golgi complex, lysosomes, peroxisomes ect.
19
Q
what are high permeability molecules
A
small nonpolar molecules
O2
CO2
N2
20
Q
what are low permeability molecules
A
small ions
Cl-
H+
K+
Na+
21
Q
what are medium permeability molecules
A
small uncharged polar molecules
(more permeable)
H2O
glycerol
large uncharged polar molecules
(less permeable)
glucose
sucrose
22
Q
Transporters are…
A
proteins that allow movement of ions or other things across membranes
23
Q
What are integral membrane proteins
A
include transmembrane
proteins that span the entire membrane
24
Q
what are peripheral membrane proteins
A
associated with either internal or external side of the membrane
25
lipid mobility
high rates of lateral mobility
flipping is rare and driven by enzymes flippases
26
Why does active transport require ATP?
An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration.
27
The movement of water into, or out of, a cell is an example of
osmosis and diffusion
28
What factor is NOT required for net movement of a substance to occur by facilitated diffusion?
ATP
29
The plasma membranes of some cells use transport proteins to move molecules out of the cell with their concentration gradient. This is an example of:
facilitated diffusion
30
The sodium potassium pump is a form of primary active transport because it directly uses ______ for energy to move molecules against their concentration gradient
ATP
31
Secondary active transport uses primary active transport to set up a _____ of one molecule which is then used to drive the movement of another molecule ______ its gradient
Secondary active transport uses primary active transport to set up a gradient
of one molecule which is then used to drive the movement of another molecule
against its gradient.
32
The plasma membranes of some cells use transport proteins and energy from ATP to directly move molecules out of the cell against their concentration gradient. This is an example of:
primary active transport
33
Does simple diffusion require energy?
no
34
Does facilitated diffusion require energy?
no
35
Does active diffusion require energy?
yes
36
What is the driving force of simple diffusion
concentration gradient
37
What is the driving force of facilitated diffusion
concentration gradient
38
What is the driving force of active transport
ATP hydolysis
39
Is a membrane protein required for simple diffusion
no
40
Is a membrane protein required for facilitated diffusion
yes
41
Is a membrane protein required for active transport
yes
42
When moving randomly which is more probable?
A: end up back where you started
B: end up somewhere else
B: end up somewhere else
43
A molecule that is _____ loses electrons, and a molecule that is _____ gains electrons.
oxidized; reduced
44
The _____ forms of the electron carriers NAD+/NADH and FAD/FADH2 have high potential energy.
reduced
45
Which example is an electron carrier in its reduced form?
ATP
NAD
NADH
ADP
NADH
46
ATP is generated in a cell by which TWO mechanisms?
oxidative phosphorylation
substrate level phosphorylation
47
Order the stages of cellular respiration in the order that they occur.
Glycolysis> Pyruvate oxidation>Citric acid cycle>oxidative phosphorylation
48
What are the OUTPUTS of glycolysis? Select ALL that apply.
Glucose
Carbon Dioxide (CO2)
NADH
ATP
NADH
ATP
49
What is energy?
the capacity to do work
50
The principle that energy cannot be created or destroyed in known as
The First Law of Thermodynamics,: the conservation of energy
51
With each energy transformation, there is a
increase in entropy, or disorder
52
a rock on the top of a mountain contains ____ energy
potential
53
ATP contains ____ energy
potential
54
A system with more H+ on one side of a membrane contains _____ energy
potential
55
The movement of H+ through ATP synthase represents ____ energy
kinetic
56
What term is used to describe a situation in which the energy released from one reaction provides the energy required for another reaction?
energy coupling
57
Energy is transferred from ATP to other molecules by transferring a
phosphate group
58
Which of the choices are components of an ATP molecule? Select all that apply.
deoxyribose
ribose
three amino groups
three phosphate groups
protein
adenine
59
Exergonic reactions _____ energy and have a ____ delta G
Such reactions are seen when polymers are _____
release, negative, broken
60
Endergonic reactions ____ energy and have a _____ delta G
Such reactions are seen when polymers ____
absorb, positive, made
61
Energy in the form of ATP is made in many cells using the energy of chemi-osmosis which means that...
a concentration gradient of ions is used to drive ATP synthesis
62
true or false
The Gibbs Free Energy of a system is defined as the system's capacity to do work.
true
63
The hydrolysis of _____ is an exergonic reaction that drives many endergonic reactions in a cell
ATP
64
Anabolic pathways of metabolism are pathways that:
build complex molecules from simple ones
65
Which of the examples are considered anabolism? Select all that apply.
a person losing weight on a calorie restriction diet
use of fat (triglyceride) stores as a cellular energy source
cells growing bigger during times of ample nutrition
hydrolysis of glycogen (a glucose polymer) during physical activity
synthesis of new DNA copies prior to cell division
66
Which of the statements describes catabolic reactions?
They are endergonic and have a positive change in free energy.
They are endergonic and have a negative change in free energy.
They are exergonic and have a positive change in free energy.
They are exergonic and have a negative change in free energy.
They are exergonic and have a negative change in free energy
67
Synthesis of a protein is an example of a chemical reaction that is:
endergonic and anabolic
68
Reactions with a negative delta G release energy and proceed spontaneously
exergonic catabolic reactions
69
Reactions with a positive delta G require energy and are not spontaneous
endergonic anabolic reactions
70
The class of organic molecules that does not typically form polymers are the:
lipids
71
Which of these choices is due to the ability of phospholipids to spontaneously form macromolecular structures when added to an aqueous solution?
The first cells.
The formation of lipid bilayers.
The ability of vesicles to bud off from the plasma membrane (endocytosis).
All of these choices are correct.
The ability of vesicles to fuse with the plasma membrane (exocytosis).
all are correct
72
Which component of a phospholipid is found in the interior of a lipid bilayer?
fatty acids
73
The interior region of a phospholipid bilayer is characterized as:
hydrophobic
74
A phospholipid molecule in a membrane can:
only flip (rotate between the two halves of the bilayer), spin (rotate around its vertical axis), and move side-to-side (lateral movement).
only flip (rotate between the two halves of the bilayer).
only spin (rotate around its vertical axis).
both spin (rotate around its vertical axis) and move side-to-side (lateral movement).
only move side-to-side (lateral movement).
both spin (rotate around its vertical axis) and move side-to-side (lateral movement)
75
Although the phospholipid molecules can be in constant lateral movement, they very rarely flip from one side of the bilayer to the other. Which of the answer choices could explain this?
The molecular attraction between the fatty acid tails is too strong.
The head groups are too large to fit between the interior fatty acid tails.
The head groups are repelled by the hydrophobic membrane interior.
The cholesterol keeps the phospholipids on the correct side.
the head groups are repelled by the hydrophobic membrane interior
76
Predict how phospholipids would arrange if they were placed in a nonpolar solution rather than a polar solution like water.
The phospholipid heads would orient toward the solution, and the tails would cluster away from the solution.
The phospholipids would form a monoilayer.
The phospholipid tails would orient toward the solution, and the heads would cluster away from the solution.
The phospholipids would form a normal liposome.
The phospholipid tails would orient toward the solution, and the heads would cluster away from the solution
77
Which choice is considered an integral membrane protein?
a protein capable of diffusing throughout the cytoplasm of a cell
A protein attached to the cytoskeleton
a protein attached to a phospholipid via ionic bonding with the head group of the lipid molecule
a protein with its amino-terminus in the cytoplasm and its carboxy-terminus in the extracellular space
a protein attached to a transmembrane protein via hydrogen bonding
a protein with its amino-terminus in the cytoplasm and its carboxy-terminus in the extracellular space
78
A protein that is found in the Golgi apparatus was synthesized where
on ribosomes bound to the rough ER
79
Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell?
C6H12O6, glucose
O2
CO2
H2O
C6H12O6, glucose
80
Why does active transport of molecules across a membrane require ATP?
An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration.
81
Secondary active transport in yeast and plant cells uses the _______ concentration gradient, whereas animal cells use the ______________ gradient.
H+ .... Na+/K+
82
Secondary active transport uses a pre-established ion gradient to move a second compound across the plasma membrane. The pre-established ion gradient arises from:
hydrolysis of ATP
83
When moving randomly which is more probable?
end up same place you started or end up someplace else
end up someplace else
84
What is diffusion?
high concentration to low concentration
no energy required
85
When does diffusion stop?
when there is no longer a concentration gradient
86
Explain osmosis vs diffusion
osmosis is a special case of diffusion involving net movement of water across a semipermeable membrane
87
Why do solutes makes free water, unfree when crossing a membrane?
water molecules that bind with solutes can no longer cross a semi permeable membrane
88
What is facilitated diffusion?
molecules move with their concentration gradient
high concentration to low
requires a membrane protein
89
Explain how glucose crosses membranes?
- glucose moves with its concentration gradient
- glucose binding causes carrier to change shape
- carrier shape change pushes glucose to the other side of the membrane
90
What is the difference between primary and secondary active transport
primary uses energy (ATP) and moves ions against concentration gradient
secondary uses the energy from the ions
91
What are phototrophs?
organisms that require energy from the sun
92
What are chemotrophs?
organisms that require energy from chemical compounds
93
What are autotrophs
carbon from inorganic sources (CO2)
94
What are heterotrophs
carbon from organic compounds
95
What are anabolic reactions
building from simple to complex
+ ^G
energetically unfavorable
endergonic
96
What are catabolic reactions
breaking down
converting energy to useable energy (glucose to ATP)
-^G
energetically favorable
exergonic
97
_____ energy is stored in chemical bonds
chemical and potential
98
High energy electrons are carried to the mitochondrial electron transport chain by
NADH
99
What is oxidation
loosing electrons
becoming more simple
100
What is reduction
gaining electrons
becoming more chaotic
101
Oxidation is ____ electrons while reduction is _____ electrons
loosing, gaining
102
What is the difference between NAD+ and NADH
NAD+
empty (no electrons)
NADH
reduced
gained electrons
103
What is glycolysis
glucose to pyruvate
6 carbons to 3 carbons
104
What is pyruvate oxidation
pyruvate to acetyl - CoA
3 carbons to 2 carbons
happens in the mitochondrial matrix
105
What is the citric acid cycle
acetyl - CoA to CO2
2 carbons to 1 carbon
happens in the mitochondrial matrix
106
What is the krebs cycle
acetyl - CoA to CO2
2 carbons to 1 carbon
happens in the mitochondrial matrix
107
What is the krebs cycle also called
citric acid cycle
108
What is the citric acid cycle also called
krebs cycle
109
Where does pyruvate oxidation happen
in the mitochondrial matrix
110
Where does the citric acid cycle happen
happens in the mitochondrial matrix
111
What is the first law of thermodynamics
energy can be changes from one form to another but it cannot be created or destroyed
112
What is the second law of thermodynamics
energy conversions increase disorder
some energy is lost as heat
decrease the useable free energy in the system
113
What is gibbs free energy
the amount of energy available to do work
114
how do you calculate ^G
products - reactants
115
What do enzymes do
proteins that serve as catalysts that lower the activation energy barrier
116
Where are the electron transport chains located
embedded in the inner membrane of the mitochondria
117
What is step one of cellular respiration
glycolysis
- glucose broken down to pyruvate
- producing ATP and reduced electron carriers (NADH, FADH2)
- happens in cytoplasm
118
What is step two of cellular respiration
pyruvate oxidation
- pyruvate converted to acetyl-CoA
- producing reduced electron carriers (NADH, FADH2) and CO2
- happens in mitochondria matrix
119
What is step three of cellular respiration
citric acid cycle or krebs cycle
- acetyl-CoA enters citric acid cycle
- produces ATP, reduced electron carriers (NADH, FADH2), and CO2
- happens in mitochondria matrix
120
What is step four of cellular respiration
electron transport chain
- reduced electron carriers (NADH, FADH2) donate electrons to the electron transport chain
- leading to the synthesis of ATP
- happens in mitochondria inner membrane
121
Why is ATP more energy then ADP
ATP has an extra phosphate
122
In the cytoplasm of the cell where is the mitochondrial matrix
look for ATP pump
123
ATP synthesis in MT is powered by H+ concentration in the _____
intermembrane space
124
High energy electrons are carried to the mitochondrial electron transport chain by _____
A. glucose
B. NADH
C. NAD+
D. ATP
NADH
125
Electrons that are passed through the mitochondrial electron transport chain are accepted by
A. ATP
B. water
C. hydrogen
D. oxygen
oxygen
126
