Unit 3 -Energy (photosynthesis, respiration, food webs) Flashcards
(101 cards)
1
Q
What is the 1st law of thermodynamics?
A
energy cannot be created nor destroyed
2
Q
What is the 2nd law of thermodynamics?
A
when energy is converted from one form to another form some energy is lost as heat
3
Q
What are the three parts of a photosystem and what are their functions?
A
a. Reaction center complex: Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis. Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain. b. Light-harvesting complex: captures light energy and transfers it to reaction center pigments in a photosystem. c. Primary electron acceptor: a specialized molecule that shares the reaction center complex with a pair of chlorophyll a molecules and that accepts an electron from them.
4
Q
What is the name of the chlorophyll a at the reaction center of PS I called?
A
P700
5
Q
In phase two, the reduction stage, what molecule will donate electrons, and so is the source of the reducing power?
A
NADPH
6
Q
What is a C3 plant?
A
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
7
Q
What percent of energy is passed from each trophic level?
A
about 10%
8
Q
What is photophosphorylation?
A
The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane or the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis.
9
Q
What is photosynthesis and why is it important?
A
The conversion of light energy to chemical energy that is stored in sugars or other organic compounds; in plants, algae, and certain prokaryotes. It is important because it is the primary consumer that starts the food chain; it is an energy source, where other animals get there food for energy.
10
Q
What is the similarity and difference between photosystem I and II?
A
Light-capturing units in a chloroplast’s thylakoid membrane or in the membrane of some prokaryotes; I. it has two molecules of P700 chlorophyll a at its reaction center. II. it has two molecules of P680 chlorophyll a at its reaction center.
11
Q
What is photorespiration?
A
A metabolic pathway that consumes oxygen and ATP, released CO2, and decreases photosynthetic output. EX: On a hot, dry day, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of O2 rather than CO2 by rubisco.
12
Q
Why are the primary producers important?
A
They are autotrophs that make up the tropic level of an ecosystem that ultimately supports all other levels.
13
Q
Who is a primary consumer? Give an example.
A
Herbivores; an organism that eats plants or other autotrophs. EX: cows, horses, zebras
14
Q
What do producers do?
A
Organisms that produce organic compounds from CO2 by harnessing light energy (photosynthesis) or by oxidizing inorganic chemicals (chemosynthetic reactions carried out by some prokaryotes)
15
Q
What is a pyruvate and where is it in cellular respiration?
A
A 3-carbon molecule (when glucose splits in two); in glycolysis and Krebs cycle
16
Q
What are redox reactions?
A
A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant another; short for reduction-oxidation reaction.
17
Q
What is a reduction?
A
The complete or partial addition of electrons to a substance involved in a redox reaction.
18
Q
Who are the secondary consumers? Give an example.
A
A carnivore that eats herbivores. EX: snakes, turtles
19
Q
What is the stroma, what does it contain, and what is it involved in?
A
The dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; it is involved in the synthesis of organic molecules from carbon dioxide and water.
20
Q
What is the substrate?
A
The reactant on which an enzyme works.
21
Q
What is the substrate-level phosphorylation?
A
The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.
22
Q
Who are the tertiary consumers? Give an example.
A
A carnivore that eats other carnivores. EX: shark, hawk
23
Q
What is allosteric regulation?
A
The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.
24
Q
What is hydrolysis and give one example of where it is used.
A
A chemical reaction that breaks between two molecules by the addition of water EX: disassembly of polymers to monomers
25
Why is carbon fixation important?
Because it is the initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (EX: a plant, another photosynthetic organism, etc.)
26
Why is the hydrogen gradient important in the production of ATP of cellular respiration?
As hydrogen moves back through the membrane through ATP synthase, the enzymatic activity of ATP synthase synthesizes ATP from ADP and P.
27
What is the reaction-center complex and what does it do?
A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor. Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis.
28
What is entropy and how is it part of the 2nd law of thermodynamics?
Entropy is a measure of disorder or randomness in a closed system and the 2nd law of thermodynamics states that there is a natural tendency of any isolated system to degenerate into a more disordered state.
29
What is the difference between competitive inhibition and noncompetitive inhibition?
In competitive inhibition, a competitve inhibitior mimics the substrate, competing for the active site. In noncompetitive inhibition, a noncompetitive inhibitor binds to the enzymes away from the active site, altering the shape of the enzyme so that the active site functions less effectively
30
What is the function of enzymes and what macromolecule are they?
Enzymes speed up reactions by providing an alternative reaction pathway that requires less activation energy and they are mostly proteins.
31
What is an enzyme-substrate complex?
An enzyme-substrate complex is a temporary complex formed when an enzyme binds to its substrate molecule.
32
What is an exergonic reaction?
An exergonic reaction is when energy is released and these reactions usually don't require energy to proceed so they occur spontaneously.
33
What is the function of FADH2?
FADH2 is a coenzyme that transfers electrons derived from glucose to ETC's along with NADH in the mitochondrial membrane during cellular respiration.
34
What is fermentation and when is the only time it takes place?
Fermentation is a metabolic process that converts sugar into acids, gases or alcohol, such as lactic acid fermentation. Fermentation takes place when the ETC is unusable because there is no oxygen present.
35
What is a food chain and what is the order of the types of organisms?
The transfer of food energy up the trophic levels from its source in plants and other autotrophic organisms (primary producers) through herbivores (primary consumers) to carnivores (secondary, tertiary, quaternary consumers) and eventually to decomposers.
36
What does a food web show and what do the arrows represent?
A food web shows the interconnected feeding relationships in an ecosystem and the arrows represent which organism eats the other.
37
What process is the starting point for either fermentation or cellular respiration and what happens during this?
Glycolysis is a series of reactions that ultimately splits glucose into pyruvate, each glucose molecule is broken down into two pyruvate molecules.
38
What are grana and where are they located?
Grana are thylakoid sacs (where the light-dependent reactions from photosynthesis take place) stacked in columns and they are located in chloroplasts which are only in plant cells.
39
What is the difference between heterotrophs and autotrophs?
Autotrophs are organisms that produce their own organic molecules from CO2 and other raw materials while heterotrophs depend on other organisms to obtain their organic molecules, autotrophs are producers and heterotrophs are consumers,
40
What is induced fit?
It is caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate.
41
What is a metabolic pathway?
It begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.
42
What are cytochromes?
Cytochromes are iron-containing proteins that are a component of the ETC's in the mitochondria and chloroplasts of eukaryotic cells and the plasma membrane of prokaryotes.
43
What is potential energy?
Energy that an object posses because of where it is located or how its structured.
44
What happens in energy coupling?
The use of an exergonic process drives an endergonic process.
45
What is ATP synthase?
A complex of several membrane proteins that functions in chemiosmosis using the energy of a hydrogen ion concentration gradient to make ATP and this is found in both eukaryotes and prokaryotes.
46
Where do Light Dependent reactions occur?
Light is absorbed by the photosystems (PS II and PS I) in the thylakoid membranes and electrons flow through electron transport chains.There are two possible routes for electron flow: noncyclic and cyclic photophosphorylation.
47
Which cycle is present in Light Independent Reactions?
The light reactions use light energy directly to produce ATP that powers the light-independent reactions. The light-independent reactions consist of the Calvin cycle, which produces sugar. To power the production of sugar, the calvin cycle uses ATP formed during light reactions.
48
What is the Matrix?
The inner region of a mitochondrion, where the Kreb Cycle occurs
49
What is a Mitochondria?
The site of cell respiration and ATP synthesis in all eukaryotic cells
50
What is the function of NAD+ in the Krebs cycle and Glycolysis?
(Nicotinamide adenine dinucleotide) A coenzyme that carries protons or electrons from glycolysis and the Krebs cycle on the electron transport chain
51
What is the purpose of NADP+?
(Nicotinamide adenine dinucleotide phosphate) Carries hydrogen from the light reactions to the Calvin cycle in the dark reactions of photosynthesis.
52
How does Noncompetitive Inhibitors differ from Competitive inhibitors?
Noncompetitive inhibitors do not directly compete with the substrate to bind to the enzyme at the active site. Instead, they impede enzymatic reactions by binding to another part of the enzyme.
53
What is the Nutrients Cycle?
A molecule that binds to a site distinct and separate from the active site of the enzyme.This binding of the inhibitor to the alternate site causes the enzyme to change shape in a way that inhibits the enzyme from catalyzing substrate into product.
54
What is Oxidation?
The loss of hydrogen (H+) or electrons (e-)
55
What is Oxidative Phosphorylation?
The production of ATP using energy derived from the electron transport chain.
56
What are Photoautotrophs? Give an example.
Are capable of synthesizing their own food from inorganic substances using light as an energy source.Green plants and photosynthetic bacteria are photoautotrophs.
57
What does Cooperativity mean?
Amplifies the response of enzymes to substrates: one substrate molecule primes an enzyme to act on additional substrate molecules more readily. Cooperativity is considered “allosteric” regulation because binding of the substrate to one active site affects catalysis in another active site.
58
What happens in Feedback inhibitation?
A metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway.
59
What are obligate anaerobes?
Organisms that carry out only fermentation or anaerobic respiration
60
What are faculative anaerobea?
Organisms such as yeasts and bacteria can make enough ATP to survive using either fermentation or respiration.
61
What happens to pyruvate during lactic fermentation?
During lactic fermentation, pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2.
62
What are the eight steps of the krebs Cycle?
1.) Acetyl CoA adds its two carbon acetyl group to oxaloacetate, producing citrate. 2.) Citrate is converted to its isomer, isocitrate, by removal of one water molecule and addition of another. 3.) Isocitrate is oxidized reducing NAD+ to NADH. Then the resulting compound loses a Co2 molecule. 4.) Another Co2 is lost,and the resulting compound is oxidized, reducing NAD+ to NADH.The remaining molecule is then attched to coenzyme A. 5.) CoA is displaced by a phsophate group, which is transferred to GTP. 6.) Two hydrogens are transferred to FAD forming FADH2. 7.) Addition of water molecule rearranges bond in substrate. 8.) The substarte is oxidized, reducing NAD+ to NADH and regenerating oxaloacetate.
63
How do humans impact the flow of the carbon cycle?
Human carbon emissions are exponentially increasing, especially as a result of industrialization and factory production.
64
Does an increase in the concentration of CO2 increase the rate of photosynthesis?
From our photosynthesis lab, testable hypotheses have been supported in showing that an increase in carbon dioxide levels does, in fact, increase the rate of photosynthesis.
65
How do plants react to different wavelengths of light and why?
In terms of plant growth, plants tend to grow best under red and blue light, and worst under green light. This is because plants have pigments that best absorb wavelengths of red and blue light, while reflecting wavelengths of green light.
66
What helps carry water through plants?
Transpiration causes tension in xylem from the roots to the leaves, as water evaporates, water is pulled up the plant. (Possible due to water cohesion)
67
What happens to a cell in a hypotonic solution?
Osmosis causes water to enter the cell, causing turgor pressure which pushes out onto the cell wall.
68
Where are membrane-bound organelles found? What is the importance of the membrane surrounding the organelles? What are examples of organelles?
Membrane-bound organelles are found in eukaryotic cells (fungi, protists, plant cells, animal cells). The membrane surrounding the organelles allow the cellular functions to be isolated and specialized. Examples of organelles include nucleus, nucleolus, ribosomes, smooth ER, rough ER, vacuole, mitochondria, lysosome)
69
What happens to a vacuole in a plant cell when its leaves are drooping and when its leaves are not?
Drooping: The central vacuole of the plant has lost a lot of its water and is shrinking away from the cell walls. The basic structure is relatively maintained due to the cell walls. Not drooping: The central vacuole is full.
70
What is the function of vesicles in the pathway of a protein synthesized within a cell?
Once a protein is processed within the golgi apparatus, the proteins leave the golgi body in a vesicle, which can bind with the plasma membrane to secrete its contents outside the cell.
71
What does water potential help us determine? How do you find water potential?
Water potential is the potential energy of water per unit area of water. Water potential helps us determine where water is going to flow. Water potential = solute potential + pressure potential
72
What is xylem and its function?
Xylem is one of the two transport tissues in vascular plants. Water and nutrients travel from the roots to the shoots of a plant through the xylem.
73
What is an absorption spectrum?
The absorption spectrum is the light absorption percentage versus the wavelength. The absorption spectrum of different pigments allows one to see at which wavelength the photosynthetic pigments work best for photosynthesis.
74
What role do accessory pigments play in photosynthesis?
Accessory pigments are light-absorbing, and work in conjunction with chlorophyll a. Accessory pigments extend the range of wavelengths that a plant absorbs. The most common accessory pigment is carotenoids, which absorb extra blue wavelengths.
75
Acetyl CoA is produced from what reaction and then enters what cycle?
Acetyl CoA is produced from the transition reaction and enters the Krebs Cycle.
76
How is an action spectrum different from an absorption spectrum? What do the differences of the two indicate?
The action spectrum shows the wavelengths of light that can be absorbed for photosynthesis, whereas the absorption spectrum shows wavelengths of light absorbed by pigments. The differences between the two indicate that pigments absorb light, not all pigments participate in photosynthesis, and the two spectrums will be different.
77
What is activation energy and how can it be altered?
Activation energy is the energy needed to start a reaction. The activation energy of a reaction can be changed due to an enzyme that helps catalyze a reaction.
78
What is an active site?
An active site is on the enzyme and it is where the substrate(s) bind so that the enzyme can catalyze a reaction.
79
What does the term "aerobic" indicate?
Aerobic indicates that an organisms utilized oxygen.
80
What is an allosteric site?
An allosteric site is a site on the enzyme separate from the active site. A molecule will bind to the allosteric site, turning on the active site by changing the shape of the enzyme.
81
What is an anabolic pathway and what are some examples?
An anabolic pathway is where smaller, lower energy molecules are built up into bigger, higher energy molecules. An example is photosynthesis (the synthesis of glucose from CO2)
82
What does anaerobic mean? Give an example of an anaerobic process?
Anaerobic is a description of an organism or process that does not require oxygen. An example of this is Fermentation which is a process in which a cell creates ATP without oxygen present.
83
What does ATP stand for? What is ATP used for?
Adenosine triphosphate. It is used as an energy source inside cells by releasing one phosphate group. It is used in several cellular processes such as synthesis metabolism and active transport.
84
Why are autotrophs special?
Autotrophs, or plants, have the ability to build molecules themselves using photosynthesis or chemosynthesis as an energy source.
85
How will a healthy individual’s ATP production change during an eight-hour fast?
The individual’s ATP production will not change significantly.Catabolism can harvest energy from fats in fatty tissue or from storage proteins or glycogen in the liver. As a result, glycolysis and cellular respiration continue to produce ATP during a fast.
86
What is a catalyst and how is it used?
A catalyst is a substance that increases the rate of reaction by decreasing the activation energy needed in a reaction. An enzyme, a biological catalyst is used in several cellular reactions.
87
What is the Calvin Cycle?
A part of photosynthesis taking place in the stroma where CO2 is transformed through a series of reactions(with the use of RuBisCo) into G3P. The three main processes are Carbon fixation, Reduction, and Regeneration of RuBisCo. Six cycles creates one glucose molecule.
88
Describe the role of photosynthesis and cellular respiration in the carbon cycle.
The carbon cycle describes the cycle of carbon between Earth's abiotic and biotic reservoirs. Photosynthesis transfers carbon from abiotic reservoirs to living organisms. Cellular respiration transfers carbon from living organisms back to abiotic reservoirs. The burning of carbon containing materials like fossil fuels also plays a role in returning carbon back to the atmosphere.
89
What is the primary role of oxygen in cellular respiration?
To act as an acceptor for electrons and hydrogen in order to form water.
90
What is chemiosmosis and how is it used?
Chemiosmosis is the moment of ions down an electrochemical gradient. It is used in the formation of ATP when H+ ions are pumped into the inner thylakoid space they more down their electrochemical gradient through ATP synthase generating ATP.
91
What is a chemoautotroph?
An organism, typically a bacterium that derives its energy through oxidation in chemical reactions.
92
Why is chlorophyll important to plant cells?
Chlorophyll, a pigment found in chloroplasts promote photosynthesis by capturing the energy from light. When photons of light interact with chlorophyll, electrons become excited. Excited electrons start the light reactions as they travel up a photosystem.
93
What are chloroplasts used for and what parts are there making up the chloroplast?
Chloroplast are organelle specific to plants that turn light energy into sugar. They are made of an outer membrane, an inner membrane, an inner membrane space, stroma, granum, and thylakoids.
94
What is a coenzyme?
A coenzyme is a small molecule that cannot by itself catalyze a reaction but can assist an enzyme catalyze a reaction.
95
What is a cofactor?
A cofactor is like a coenzyme in that it can help an enzyme however cofactors are typically ions not organic molecules.
96
What is a competitive inhibitor?
A competitive inhibitor is a molecule that binds to an enzymes active site effectively stopping the enzyme from catalyzing any more reactions.
97
What are the different kinds of consumers and how do they vary?
Primary consumers, or herbivores solely eat autotrophs. Secondary consumers eat both plants and/or animals such as herbivores and autotrophs. Secondary consumers include omnivores and carnivores. Tertiary consumers are carnivores that eat other carnivores. They are the highest level of consumers. As the levels of consumers increase, the number of consumers per level decreases.
98
What is a cristae?
A cristae is a fold in the membrane of a mitochondria, giving the inner membrane a larger surface area for reactions.
99
Where do detritivores get their energy?
Detritivores are consumers that acquire their energy from detritus, or waste and debris.
100
What does ETS/ETC stand for and what does it do?
Electron Transport System/Chain. The ETS is a series of reactions in which ATP is generated by pumping ions across membranes and through enzymes. This occurs in both photosynthesis and cellular respiration.
101
What is an endergonic reaction?
A reaction that is non spontaneous meaning it requires energy to start the reaction and energy in the reaction is absorbed.
