Exam 2 Flashcards
1
Q
the capacity to do work
A
energy
2
Q
how does position affect energy?
A
a higher position creates a higher potential energy because of gravity
3
Q
What doest the first law of thermodynamics state?
A
Conservation of energy: amount of energy in a system remains constant
4
Q
What does the second law of thermodynamics state?
A
When converted from one form to another, useful energy decreases. Because of this, entropy increases.
5
Q
When energy is converted, what is it lost as?
A
heat
6
Q
forming and breaking of bonds among atoms
A
chemical reactions
7
Q
what type of reaction is the burning of glucose in mitochondria?
A
exergonic
8
Q
what type of reaction is photosynthesis?
A
endergonic
9
Q
What is required for the synthesis of ATP?
A
ADP + energy + inorganic Phosphate
10
Q
What is released in the breakdown of ATP?
A
ADP+ energy + inorganic Phosphate
11
Q
Explain a coupled reaction in a living cell.
A
Glucose breaks down to produce CO2, H2O, and heat. That exergonic reaction gives off energy to charge ATP synthesis which then breaks down to create ADP. ATP gives energy to amino acids to create a protein.
12
Q
How do cells control their metabolic reactions?
A
limit production of ATP. Too much ATP slows down metabolic production of ATP and vice versa
13
Q
sum of all of the chemical reactions in a cell
A
metabolism
14
Q
How is metabolism controlled?
A
Enzymes regulate chemical reactions. Cells couple the reactions, and energy carriers capture carriers from exergonic reactions and deliver to endergonic reactions
15
Q
What are the five properties of biological catalysts (enzymes)? 3 for all catalysts. 2 for only enzymes
A
- Speed up reactions
- Speed up reactions that would occur anyway
- Not consumed in reactions
- Enzymes are very specific
- Enzyme activity is regulated
16
Q
What are the steps in enzyme-substrate interactions
A
- Substrates enter active site
- Shape change promotes reaction
- Product released; enzyme ready to start again
17
Q
What are three types of enzyme regulation?
A
Feedback inhibition. Allosteric regulation. Competitive inhibition.
18
Q
inhibits an enzyme in the metabolic pathway by stopping production of a product if too much already exists
A
Feedback inhibition
19
Q
Explain allosteric regulation
A
inhibits the enzyme by changing the shape of the active site. The shape is changed by an allosteric regulator going into the allosteric regulation site.
20
Q
Explain competitive inhibition
A
competitive inhibitor occupies the active site and blocks the substrate from going in there
21
Q
What type of organisms use photosynthesis?
A
Plants, Bacteria, Protists (Algae)
22
Q
What can occur if the stomata is open?
A
Water can leave and CO2 can get into the leaf
23
Q
What can occur if the stomata is closed?
A
CO2 cannot enter the leaf which may result in no photosynthesis
24
Q
microscopic opening in the epidermis of leaves that allow the exchange of gases between the outside air and the inside of the leaf
A
stomata
25
How do the stomata open?
Ions are actively put into the guard cells, and the water follows it by osmosis. Limp cells become turgid and open the stomata
26
How do the stomata close?
Ions are actively taken out of the guard cells and the water follows by osmosis. Turgid cells become limp and close the stomata
27
What factors control stomata opening and closing?
CO2 concentration and Humidity
28
How does CO2 concentration control the stomata?
when the concentration in the leaf falls the guard cells become turgid and open the stomata
29
How does humidity control the stomata?
Stomata close on hot, dry, windy days. At dawn a sudden increase in stomata opening, reaching a max near noon, is followed by a decline because of water loss.
30
How does water leave the turgid guard cells?
aquaporin channel
31
cells inside the leaf
mesophyll cells
32
What do veins inside of the leaf transport?
Sugars
33
What are the components of the chloroplast?
inner and outer membranes, stroma, thylakoids, granum, circular DNA
34
What are the two main parts of photosynthesis and where do they occur?
Light Dependent (thylakoids) and Light InDependent (stroma)
35
What happens in the Light Dependent reactions?
Depleted carriers (ADP, NADP+) react with light and H2O to become energized carriers (ATP, NADPH) and give off oxygen as a byproduct
36
What happens in the Light Independent reactions?
Energized carriers (ATP, NADPH) react with CO2 and H2O to become depleted carriers (ADP, NADP+) and give off glucose as a byproduct
37
What are the three photosynthetic pigments?
Chlorophyl, Carotenoids, Phycocyanins
38
How does chlorophyll acquire its pigment?
Absorbs violet, blue, and red. Reflects Green
39
How do carotenoids acquire their pigments?
Absorb blue and green. Reflect yellow, orange, and red.
40
How do phycocyanins acquire their pigments?
Absorb green and yellow. Reflect blue and purple
41
What would happen to a plant grown in only green light?
It would die because photosynthesis would not occur
42
energy of photons is used to synthesize ATP and NADPH
light dependent reactions
43
energy stored in ATP and NADPH is used to synthesize glucose
light independent reactions
44
What does photosystem II in the light dependent reactions in the thylakoid do?
Builds a proton gradient inside thylakoid, the difference in H+ is used to charge ATP synthase. Splits H2O to replace electrons. Delivers electrons to PS I
45
What is generated in PS II? What is generated in PS I?
PS II - ATP
| PS I - NADPH
46
How are electrons used in photosynthesis replaced and where?
Electrons are replaced by the splitting of water in PS II inside the thylakoid membrane
47
Where do PS II and PS I occur?
Thylakoid membrane
48
The fourth step in the ZED scheme of photosynthesis in chloroplast, and it results in ATP generation in chloroplasts, mitochondria and bacteria.
Chemiosmosis
49
What are the two steps to chemiosmosis?
1. As excited electrons are passed down the ETS, protons are pumped across a membrane to form a concentration gradient.
2. As the protons come back through a membrane channel protein (facilitated diffusion) ATP is generated.
50
a molecular motor in the thylakoid membrane that catalyzes ADP + P
ATP synthase
51
first to propose general mechanism of ATP synthesis called chemiosmosis
Dr. Peter Mitchell
52
What happens when you turn on the light in a room with a plant?
O2 goes up and CO2 goes down. Vice-Versa for the light off
53
What happens in the light independent reactions (aka Carbon fixation, C3 cycle, Calvin-Benson cycle)? Where?
CO2 is converted into glucose in the stroma of chloroplasts
54
What are the three steps of the C3 cycle?
1. Carbon fixation combines 6CO2 with 6RuBP.
2. G3P synthesis uses energy. 12 ATP to 12 ADP and 12 NADPH to 12 NADP+ to result in 12 G3P. Two G3P is available for synthesis of organic molecules.
3. RuBP synthesis uses energy and 10 G3P. 6 ATP to 6 ADP.
55
What is necessary in the C3 cycle of carbon fixation?
Need ATP and NADPH from light reactions, enzymes to form products through cycle, water, and CO2
56
Most abundant protein on the planet
Rubisco
57
What does rubisco recognize as substrates?
RuBP (5 carbon sugar), CO2, and O2
58
What is it called if rubisco connects to oxygen instead of carbon dioxide?
photorespiration
59
When does photorespiration occur and what does it produce?
Much photorespiration occurs under hot, dry conditions. It eventually produces some CO2 and amino acids but not much glucose
60
Full name of rubisco
ribulose biphosphate carboxylase oxygenase
61
Why did the C4 plants evolve throughout history?
To make up for the oxygenate reaction from rubisco
62
Which chloroplasts use the C3 cycle?
Only chloroplasts in the bundle-sheath cells use the C3 cycle
63
Where does the C4 pathway occur?
In the mesophyll cells in the C4 plant
64
What is produced in the C4 pathway to be used in the C3 cycle?
CO2
65
What is the full name of PEPc and what does it do?
phosphoenolpyruvate carboxylase
| only fixes CO2
66
What is CAM (crassulecean acid metabolism)?
temporal separation of photosynthesis divided by night and day
67
Where does the Kreb's cycle occur?
Mitochondrial matrix
68
What happens to aerobic respiration if oxygen is not present?
The last stem of ATP production (ETS) does not happen, cycle backs up to glycolysis and instead of Acetyl CoA being produced, the cell goes through fermentation which produces lactate or ethanol and CO2
69
Where does fermentation occur?
in the cytosol
70
What is the structure of a mitochondrion?
outer and inner membrane, intermembrane compartment, matrix, cristae
71
What are the five steps in cellular respiration?
1. Glucose is converted to pyruvate through glycolysis, and the pyruvate
2. Pyruvate is converted to Acetyl CoA
3. The Kreb's cycle releases CO2 and energized electron carriers.
4. Energized electron transport system
5. H+ builds up in the inter membrane compartment and gives energy to chemiosmosis to make ATP
72
Where does glycolysis occur?
Cytoplasm of the cell
73
Where does the Kreb's cycle occur?
Mitochondrial matrix
74
Where does the ETS occur? (aerobic respiration)
in the inner membrane of the mitochondria
75
How much ATP is one NADH
3
76
How much ATP is one FADH2
2
77
What is used in the Kreb's cycle? What is formed?
Used: 2 acetyl-coA's, ADP, NADP+, FAD+
Formed: 6 NADH, 6 FADH2, 2 ATP
78
Why is a buildup of CO2 in the Kreb's cycle bad?
It inhibits the enzymes in the Kreb's cycle because too much CO2 builds up acid in the body
79
What are the steps of glycolysis?
A six carbon glucose takes a phosphate from ATP to produce fructose diphosphate and ADP. The fructose diphosphate divides into 2 G3P which give up their phosphates to form ATP and are acted upon by NAD+ to form 2 three carbon pyruvate and give off NADH
80
What are the products of glycolysis?
2 pyruvates, 2 ATP, 2 NADH
81
What are the steps in the formation of acetyl CoA?
2 pyruvate are acted upon by NAD to release two CO2 and NADH. Co enzyme A acts on the leftover carbons to form acetyl CoA
82
How does the mitochondrial ETS work?
Proteins form a "wire." NADH and FADH2 from the Kreb's cycle deposit two electrons into the inner membrane of the mitochondria which move through proteins. The proteins use the energy to pump H+ through the inner membrane for chemiosmosis to occur (similar to photosynthesis) and make ATP
83
Where does the oxygen for mitochondrial chemiosmosis come from and what does it do?
Oxygen comes from the blood stream to the cell's mitochondria and associates with the last step of the ETS and acts as an electron accepter to make water. O2 is being reduced.
84
Each NADH pumps enough H+ into the inter membrane space to phosphorylate _ ATP
3 ATP
85
Each FADH2 pumps enough H+ into the inner membrane space to phosphorylate _ ATP
2 ATP
86
When did photosynthesis evolve?
Before aerobic respiration and first eukaryotes with mitochondria
87
What is the purpose of fermentation?
To regenerate NAD+ used in glycolysis to make some ATP
88
How does lactate fermentation occur?
6 Carbon glucose goes through glycolysis to produce 2 3-Carbon pyruvates. Lactate fermentation forms the 2 3-Carbon pyruvate into 3-Carbon Lactates. (NADH from glycolysis is used in fermentation and creates NAD+)
89
How does alcoholic fermentation occur?
6 Carbon glucose goes through glycolysis to produce 2 3-Carbon Pyruvates. Alcoholic fermentation forms the 2 3-Carbon Pyruvates into 2 3-Carbon ethanols and 2 CO2 molecules.
90
Where does fermentation occur?
In the cytosol
91
What are the products of fermentation?
Lactic acid in an athlete's muscle, yogurt, and sour cream. CO2 and ethanol in beer, champagne, and bread.
92
What are the two types of poisons?
Inhibitors of oxidative phosphorylation and Uncouplers of oxidative phosphorylation.
93
How do inhibitors of oxidative phosphorylation work?
Poisons such as Cyanide and Rotenone interfere with the ETS. 2 ATP from glycolysis are created until the cell dies. They inhibit the flow of electrons like when there is no O2 present.
94
How do uncouplers of oxidative phosphorylation work?
Poisons such as 2,4-DNP and thermogenin embed themselves in the hydrophobic region of the mitochondrial membrane and grab protons and rotate themselves to release the protons on the wrong side. They allow protons to leak across the membrane and mess with the concentration gradient. 4 ATP created (2 from glycolysis and 2 from Kreb's) until dead.
95
What is phosphorylation and what does it require?
Phosphorylation is the adding of a phosphate group and it requires energy
96
How is cellular energy carried between coupled reactions?
Posphorylation and dephosphorylation of ATP
97
How does CAM work?
Plants open up guard cells at night to let CO2 in and does the C4 pathway at night (PEPc bonds with CO2 to produce malate which is stored at night). The malate is used in the day to make the pyruvic acid that goes into the C4 pathway and the CO2 that is used in the day in the C3 cycle
98
Where are most CAM plants found? Why?
Most CAM plants are found in the desert because of it's dry and hot conditions, guard cells would not be able to open up in the daytime to allow CO2 in.
99
How much ATP would be produced if uncouplers entered the thylakoid membrane? What would happen to the pH in the stroma and inside of the thylakoid?
No ATP production. pH remains balanced so no H+ gradient
