Exam 2 Flashcards
1
Q
Nucleus
A
Stores Information (DNA and RNA)
2
Q
Mitochondria
A
Powerhouse of the cell
harness energy for the cell
3
Q
Plasma Membrane
A
gatekeeper
4
Q
Endoplasmic reticulum
A
involved in the synthesis of proteins and lipids.
5
Q
Cytoskeleton
A
protein scaffold that provides the cell structure
6
Q
Lysosome
A
contain enzymes that break down proteins, nucleic acids, lipids, and carbohydrates
Acidic (pH 5)
7
Q
Golgi apparatus
A
modifies proteins and lipids produced by the ER and acts as a sorting station as these molecules move to their final destinations
Synthesize sugars/carbohydrates
8
Q
Peroxisomes
A
lipid synthesis and breakdown
9
Q
Cell wall
A
Only plant cells
a rigid barrier of poly-saccharides
10
Q
Chloroplasts
A
Only plant cells
Harness light energy
11
Q
Vacuoles
A
Only plant cells
maintain turgor pressure against cell walls
12
Q
Plasmodesmata
A
Only plant cells
connect neighboring plant cells
13
Q
Rough ER
A
ribosomes
Attach to the ER and make it rough looking
Transmembrane and secreted proteins are synthesized by rough ER (RER)
14
Q
Smooth ER
A
no ribosomes
It is the primary site of lipid synthesis
Portions of the smooth ER bud off to produce vesicles that are free to move in the cytosol
15
Q
Exocytosis vs endocytosis
A
Exo: Send material out of the cell through a vesicle
Endo: material from outside the cell is brought into a vesicle that can then fuse with other organelles
16
Q
Autophagy
A
a cellular process where cells break down and recycle their own components, such as proteins, organelles, and cellular debris
17
Q
2 main classes of proteins
A
- made in cytoplasm - cytosolic (make up stuff) or peripheral membrane proteins
- made in Rough ER - transmembrane
18
Q
Signal recognition particle
A
binds the ER signal sequence and threads it into a channel in ER
19
Q
Signal anchor sequence
A
a hydrophobic sequence that keeps proteins in the membrane
20
Q
ER signal sequence
A
if present translation occurs on ER. When absent translation occurs in the cytoplasm
21
Q
Phospholipids
A
Make up membranes
Amphipathic - have hydrophilic heads and hydrophobic tails (made of C and H)
Form bilayers
22
Q
How does temperature effect lipid fluidity?
A
Cool temps - lipids become solids
Hight temps - lipids become fluid
23
Q
Saturated fatty acids
A
Straight
Decreases membrane fluidity
More prevalent in warm blooded animals/when body temperatures increase
Tails interact through van der walls forces
NO DOUBLE CARBON BONDS
24
Q
Unsaturated fatty acids
A
Bent
Increases membrane fluidity
More prevalent in cold blooded animals
25
The longer the tail...
The stronger the force of attraction and less fluid the membrane
26
Cholestrol
Amphipathic - allows it to pack close with phospholipids in cell membranes
keeps membrane from becoming too fluid or rigid
27
How does temperature effect cholesterol fluidity?
Cool temps - cholesterol becomes more fluid
Hight temps - cholesterol becomes less fluid
28
What molecules can/cant pass through simple diffusion
small, non-polar molecules can
Polar, charged, large molecules cant
29
Diffusion
molecules move high to low concentration
"random walks"
30
Hypertonic
higher solute concentration outside the cell than inside
water leaves cell by osmosis and cell shrivels
31
Isotonic
Solution with equal solute concentration inside and outside the cell
cell stays the same
32
Hypotonic
lower solute concentration outside the cell than inside
water moves into the cell by osmosis and the cell will swell and maybe burst
33
Facilitated diffusion
Diffusion aided by proteins
Allow polar and charged molecules to cross (R - groups)
34
Aquaporin
Protein channels for water specifically
35
Active Transporters
Use energy to create concentration gradients
equation: DG = RT ln [inside]/[outside]
36
Metabolic Pathways
the sum of biochemical reactions required for life
37
Catabolic Pathways
Break down complex molecules into simpler compounds to RELEASE ENERGY
38
Anabolic Pathways
Build complicated molecules from simpler ones by CONSUMING ENERGY
need catabolic pathways to provide energy
39
Thermodynamics
a branch of physics concerned with heat and temperature and their relation to other forms of energy and work
40
1st law of thermodynamics
Energy cannot be created or destroyed, it only change forms
41
2nd law of thermodynamics
The entropy (S) in a closed system can stay the same or increase but can never decrease
42
Entropy (S)
a measure of disorder/randomness; a measure of how much "work" is unavailable
EXAMPLE: (if you have a factory with a lot of "workers" who have the "energy" to do "work", you have a LOW level of disorder (entropy); if you have a factory with very little "workers" and they all have little "energy" to do "work" you have a HIGH level of disorder (entropy) )
increases when concentration gradient is small and when multiple molecules are created from a single molecule
decreases when concentration gradient is large and a single molecule forms from multiple molecules
43
44
Enthalpy (H)
Energy stored in chemical bonds
DH = energy of bonds broken - energy of bonds formed
when DH is negative, energy is released
45
Free Energy (G)
Measure of enthalpy (H) and entropy (S)
Total energy that is free to enter and leave a system
46
Exergonic
| +G or -G
spontanious or nonspontanious
Releases free energy
G is negative
SPONTANIOUS
47
Endergonic
| +G or -G
spontanious or non-spontanious
absorbs free energy
G is positive
NON-SPONTANIOUS
48
Exothermic
Reaction that releases heat into the surroundings
49
Endothermic
Reaction that absorbs hear from the surroundings
50
ATP hydrolysis
Exergonic reaction (-G): small amount of energy is used to break bonds to make H2O and ATP, but a lot of energy gets released when H2O and ATP are broken into ADP and Pi
G = -7.3 kcal/mole
51
Concentration gradient equation
DG = DS x T = RT ln ([X]in / [X]out)
Tells us how much free energy is stored in a concentration gradient
Also tells us how much energy it takes to make a concentration gradient (+G)
52
Uniporter
transports one molecule
53
Symporter
transports two molecules in the same direction
54
Antiporter
transports two molecules in opposite directions
55
Secondary Active Transport
A gradient is first formed by active processes (using energy)
The gradient is used to move a second molecule
56
Reactants (substrates) vs products
Reactants (substrates) - the starting materials for a chemical reaction
Products - what forms
57
Equilibrium
the ratio of reactants and products is constant
G = 0
58
Le Chatelier's principle
When the system is out of equilibrium, it moves towards equilibrium
Energy is released as the system changes
59
G in chemical reactions
| G+ vs G-
How far from equilibrium
-G: tells how much energy will be released as the system goes to equilibrium
+G: tells how much energy is needed to move the system away from equilibrium
60
Hydrolysis vs Synthesis of ATP
Hydrolysis: spontaneous, releases energy when going to equilibrium
Synthesis: non-spontaneous, requires the same input of energy
61
Keq (equilibrium constant)
The ratio of the concentrations of products and reactants at equilibrium
G = RT ln(Q/K)
Q gives the starting ratio of the concentration of products over reactants
62
Enzymes
Catalyze reactions by lowering activation energy
No effect on G
Not consumed by the reactions they catalyze
Specific for their substrates
63
Redox reactions
Reduction and oxidation
The reactions are paired
Redox involves electron transfer
Electron transfer > charges > ionic bonds > forming stronger bonds releases energy
64
Reduction vs oxidation
Reduction Is the Gain of electrons (RIG)
Oxidation Is the Loss of electrons (OIL)
65
Activation energy
Amount of energy required to break bonds
66
Temperature effect on velocity/energy
As temp increases, the average velocity increases
As temp increases, more molecules have the energy to enter the transition state/pass the activation barrier
67
Phosphorylation
Cells transfer phosphate from ATP to glutamate
Creates a weak phosphate bond
-G, spontaneous, and exergonic
step one in chemical formation with ATP
68
Energy coupling by ATP
Find the DG of the reaction of interest, and the DG of ATP
(or other coupled reaction) and add the numbers together
If net DG is negative, the reaction is spontaneous and exergonic (FAVORABLE)
69
Monosaccharides
Fuel
Rich in weak, non-polar C-C and C-H bonds
Hydroxyl groups make them soluble in water
70
Disaccharides
Fuel transport
Made of two monosaccharides
71
Polymers
Fuel storage and structure
72
ATP
Powers our muscles
powers macromolecule synthesis
Creates concentration gradients
73
Overview of ATP protuction
Glycolysis - makes a little ATP and reduces NAD+ to NADH
when high O2 - aerobic respiration - NADH used to make ATP via oxidative phosphorylation
when low O2 - fermentation - NADH is oxidized back to NAD+, so glycolysis continues
74
Glycolysis
Stage 1 of cellular respiration
Exergonic
Takes place in cytoplasm
Creates NADH from glucose
Glucose + water = CO2 (exhaled), electrons, and protons
NAD+ becomes NADH
Produces 2 molecules of pyruvate (3 carbons)
Net yeild 2 ATP and 2 NADH
75
Fermentation
generates ATP at low O2 and in bacteria
Anaerobic
occurs in cytoplasm
Oxidizes NADH to NAD+, so glycolysis continues
Reduces pyruvate to make either lactate of ethanol
Generates 2 ATP/glucose by substrate level phosphorylation
76
Matrix
Mitochondrial sub-cellular site of pyruvate oxidatoin and the krebs cycle
77
Inner membrane
Site of the electron transport chain and ATP synthase
78
Crista
A fold of inner membrane
79
Outer membrane
encloses mitochondria
80
Pyruvate oxydation
Pyruvate + CO2 +NADH = Acetyl-CoA (enter the Krebs cycle)
NAD+ is reduced to NADH and pyruvate is oxidized
occurs in mitochondria
81
B-oxidation
Generates NADH and Acetyl-CoA
occurs in mitochondria
CoA binds to the end of a fat to make Acetyl-CoA which enters Citric Acid Cycle
82
Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle
Makes CO2 and NADH
occurs in mitochondrial matrix
2 Acetyl-CoA + ADP + NAD+ + FADH = 4 CO2, 2 ATP, 6 NADH, 2 FADH2
NADH and FADH are sent to electron transport chain
83
Electron Transport Chain
Takes electrons from NADH and uses their potential energy to pump protons into the inter-membrane space
Electrons from NADH end up in water
84
ATP synthase
Sits in the inner membrane
Generates ATP as protons flow from the inter-membrane space back into the matrix
Inter-membrane space has the lowest pH because it has most H+
85
Uncouplers
Disrupt the 'coupling' between the generation of the mitochondrial membrane potential and ATP generation
They disrupt the proton gradient
86
Regulation of ATP production
Feedback loop
ADP and NAD+ indicate a low energy state and stimulate metabolism
ATP and NADH indicate a high energy state and inhibit metabolism
87
Goal of photosynthesis
| Anabolic or Catabolic
Incorporate CO2 into organic molecules and return O2 to the atmosphere
synthesis of glucose
Anabolic
88
Autotrophs
synthesize their own organic molecules (food) from inorganic CO2 using light energy
89
Heterotrophs
Must consume organic molecules (food) produced by other organisms
90
Light reactions
occur in thylakoid membrane
Requires light and H2O
O2 is waste product of water
Generates ATP and NADPH needed by Calvin Cycle
91
Light Independent Reactions/Dark Reactions/Calvin Cycle
Occurs in the stroma
Does not require light
Requires CO2, ATP, and NADPH
Creates sugars
92
Photosystem II
Breaks down water to supply electrons to protons, O2, and electrons through energy in photons
93
Photosystem I
Raises electrons to higher energy levels to make NADPH
boosts the energy levels of electrons to power ATP generation via chemiosmosis or to react with NADP+ and H+ to make NADPH
94
Chemiosmosis
the movement of molecules across a semipermeable membrane
95
Photophosphorylation
The production of ATP during photosynthesis
In contrast, oxidative phosphorylation is the production of ATP in mitochondria.
96
Calvin Cycle process
- CO2 enters one molecule
- a protein called rBisCO adds CO2 to 5 carbon molecule RuBP (creates 6 carbon molecule that splits into 3 carbon molecule PGA)
- PGA reduced by NADPH to G3P
- ATP is used to generate RuBP from G3P
97
Fixation/Carboxylation
CO2 enters Rubisco one at a time
It is added to RuBP to make PGA
98
Reduction
ATP and NADPH are used to reduce PGA to G3P
Two G3Ps exit to make glucose
99
RuBP Regeneration
G3P is converted back to RuBP
100
In photosynthesis
Water is directly broken down with light to make oxygen in the light reactions.
Carbon dioxide is directly converted into sugars in the Calvin cycle.
CO2 conversion to O2 does not occur
101
Rubisco
The most abundant protein on earth
Processes RuBP to convert CO2 into sigar
102
Photorespiration
a process in plants that involves the uptake of oxygen and release of carbon dioxide (uses energy) in response to light
happens in the presence of Oxygen, inhibiting photosynthesis
