TExES Life Science 7-12 > Energy Pathways in Cells > Flashcards

Energy Pathways in Cells Flashcards

Understand how organisms produce and use energy through ATP, photosynthesis, cellular respiration (aerobic/anaerobic), and chemosynthesis. (100 cards)

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1
Q

What are the two types of metabolic pathways?

A
  • Catabolic pathways
  • Anabolic pathways
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2
Q

What do enzymes do in metabolic pathways?

A

Catalyze the reactions, influencing the speed, direction, and occurrence of reactions.

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3
Q

What is a catabolic pathway?

A

A set of biochemical reactions that break a substance down into its component parts, releasing energy that is used by the cells for other functions.

Examples: Cellular Respiration, Citric or Krebs Cycle, Glycolysis.

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4
Q

What is a metabolic pathway?

A

A series of steps found in biochemical reactions that help convert molecules or substrates into different, more readily usable materials.

Metabolic pathways produce exactly what the body needs, especially for generating the energy required for various body functions.

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5
Q

What is an anabolic pathway?

A

A set of biochemical reactions that build substances from other materials, requiring energy to occur.

Examples: Building proteins from amino acids. Making sugar from carbon dioxide.

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6
Q

What is the tool used to view how different metabolic pathways are connected?

A

Biochemical pathway diagrams/flowcharts

Pathway diagrams illustrate how enzymes link reactions, showing how biochemical processes connect.

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7
Q

What does the term ‘metabolism’ refer to?

A

The sum of all an organism’s chemical reactions.

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8
Q

What enzyme is responsible for the gradient-driven phosphorylation of ADP into ATP?

A

ATP synthase

ATP synthase, in the mitochondrial inner membrane, uses the proton gradient to produce ATP.

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9
Q

What is the role of coenzyme NAD+ in glycolysis?

A

It picks up an electron when it is reduced to become NADH.

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10
Q

What is the coenzyme in cells that collects electrons and carries them to another location?

A

Nicotinamide adenine dinucleotide

(NAD⁺)

NAD⁺ is an electron carrier that accepts electrons during glycolysis and the Krebs cycle.

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11
Q

What is the enzyme that catalyzes the fixation of carbon dioxide with RuBP in the Calvin cycle?

A

RuBisCo

(ribulose-1,5-bisphosphate carboxylase/oxygenase)

This process is going to create 6 molecules of glyceraldehyde-3-phosphate (G3P).

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12
Q

What is the role of enzymes in relation to ATP?

A

They break the phosphate bonds in ATP to release energy for cellular reactions.

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13
Q

Where does oxidative phosphorylation occur?

A

inner mitochondrial membrane

It is where the ETC creates a proton gradient to drive ATP synthesis.

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14
Q

Fill in the blank:

Chemiosmosis generates ATP in mitochondria for cellular respiration and chloroplasts for _______.

A

photosynthesis

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15
Q

How is ATP created?

A

In cellular respiration, glucose is broken down to produce ATP, which serves as the primary energy currency in cells.

Key processes in cellular respiration:

  1. Glycolysis
  2. Anaerobic Respiration
  3. Aerobic Respiration

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16
Q

How many molecules of ATP are produced by oxidative phosphorylation from each molecule of glucose?

A

approximately 28 ATP

ATP synthesis occurs in and across the mitochondrial membrane.

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17
Q

How much ATP is produced by the electron transport chain in aerobic cellular respiration?

A

28 molecules of ATP

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18
Q

List the three sections of the ATP molecule.

A
  • Sugar molecule called ribose.
  • Base known as adenine.
  • Group of three phosphates.
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19
Q

What are the products of oxidative phosphorylation?

A
  • Adenosine triphosphate
  • NAD+
  • FAD
  • Water
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20
Q

What are the steps of oxidative phosphorylation?

A
  1. NADH and FADH2 donate their electrons to the electron transport chain.
  2. Electrons moving across the chain produce energy to establish an electrochemical gradient.
  3. Oxygen becomes the final electron acceptor, binding with hydrogen ions to form water.
  4. The electrochemical gradient powers ATP synthase for ATP production.
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21
Q

What are the two connected processes involved in oxidative phosphorylation?

A
  • electron transport chain
  • chemiosmosis
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22
Q

What is oxidative phosphorylation?

A

The generation of ATP by the chemiosmosis process in mitochondrial membranes.

It occurs during cellular respiration.

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23
Q

What is reduced to NADPH during the light-dependent reactions in photosynthesis?

A

NADP+

During the light reactions, NADP⁺ is reduced to NADPH by electrons from the ETC.

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24
Q

Define:

substrate-level phosphorylation

A

A metabolic process that produces ATP by directly transferring a phosphate group from a substrate to ADP.

This occurs independently of the electron transport chain.

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25
What is the **chemical formula** for ATP?
**C10H16N5O13P3** consists of adenine, ribose, and three phosphate groups. ## Footnote * 10 Carbon * 16 Hydrogen * 5 Nitrogen * 13 Oxygen * 3 Phosphorus
26
What is the **driving factor** for ATP synthesis in mitochondria?
A larger concentration of **protons outside the inner membrane** than within the matrix. ## Footnote This creates a proton gradient utilized in chemiosmosis.
27
What is the function of **ATP synthase** in the electron transport chain?
A channel protein that allows protons to cross the inner membrane back into the mitochondrial matrix, **catalyzing the phosphorylation of ADP to produce ATP**. ## Footnote ATP synthase creates 28 ATP molecules.
28
What is the **low-energy molecule** formed when ATP loses a phosphate?
ADP ## Footnote ADP forms when ATP loses a phosphate group, releasing energy for cellular processes.
29
What is the main function of **oxidative phosphorylation**?
To create a large number of ATP molecules.
30
What is the primary process that **results in ATP production** during the electron transport chain?
Chemiosmosis
31
What is used to convert **ADP** back into **ATP**?
phosphorylation ## Footnote This is the process of adding a phosphate group to a molecule.
32
Where is ATP found in **animal** and **plant** cells?
* **Animal cells**: mitochondria and cytoplasm * **Plant cells**: mitochondria, chloroplasts, and cytoplasm
33
What is the **primary pigment** in plants responsible for capturing light energy?
Chlorophyll ## Footnote Chlorophyll is the main pigment that captures light to drive photosynthesis in plants.
34
What is the **process** in which sunlight catalyzes the splitting of water into separate hydrogen and oxygen atoms called?
Photolysis
35
What is the **energy** used by all living organisms?
Adenosine triphosphate ## Footnote Most energy is stored in the bond between the second and third phosphate. ATP is used for cellular processes such as active transport and cell-to-cell communication.
36
What is the **equation** of light-dependent reaction?
Water (in the presence of light) + NADP + ADP --> Oxygen + NADPH + ATP ## Footnote Oxygen is created by water molecules breaking apart
37
Where does **photosynthesis** occur in plants and algae?
In organelles called **chloroplasts**.
38
How many **molecules** of G3P are needed to produce one molecule of glucose in the Calvin cycle?
six
39
What are the **products** created during photosynthesis?
* Oxygen * Glucose
40
What are the **products** of the Calvin cycle?
* Glyceraldehyde 3-phosphate (G3P) * ADP * NADP+
41
What are the **products** of the light-dependent reaction in photosynthesis?
* Oxygen * ATP * NADPH
42
What are the **reactants** needed for photosynthesis to occur?
* Water * Carbon dioxide * Light
43
What are the **reactants** of the Calvin cycle?
* CO2 * ATP * NADPH
44
What are the **three main stages** of the Calvin cycle?
1. Carbon fixation 2. Reduction 3. Regeneration
45
What are the **two main photosystems** in photosynthesis?
Photosystems I and II ## Footnote These are utilized in light-dependent reactions.
46
What are the **two reactions** that take place during photosynthesis?
* Light-dependent reactions * Light-independent reactions ## Footnote Light-independent reaction is also known as the Calvin Cycle.
47
What do photosynthesis and chemosynthesis both **produce**?
Food energy (glucose) and a byproduct.
48
What does **Photosystem I** do?
Captures high energy electrons, and passes them down an electron transport chain to **produce NADPH**. ## Footnote This occurs after photosystem 2.
49
What is **photosynthesis**?
Uses light energy to **convert carbon dioxide and water** into **carbohydrates and oxygen** within chloroplasts.
50
What is **reduction** in the Calvin cycle?
The process of **reducing** 3-phosphoglyceric acid (3-PGA) to **produce glyceraldehyde 3-phosphate (G3P)** using ATP and NADPH for energy.
51
What is **unique** about plant cells when it comes to photosynthesis and cellular respiration?
**Plant cells can do both** photosynthesis and cellular respiration. ## Footnote Animal cells can only perform cellular respiration.
52
What is a **photosystem**?
**Functional units for photosynthesis**, containing chlorophyll molecules, accessory pigments, and proteins. ## Footnote Organized into 2 identified systems: photosystem1 and photosystem 2
53
What is the **difference** between photosynthesis and chemosynthesis?
* **Photosynthetic organisms** need sunlight to make food energy. * Organisms that use **chemosynthesis** do not require sunlight but need inorganic chemicals from their environment. ## Footnote Photosynthesis generally occurs in plants, protists, and cyanobacteria, while chemosynthesis occurs in some bacteria and archaea.
54
What is the **regeneration** stage in the Calvin cycle?
The process of **recycling** G3P to **produce Ribulose 1,5-bisphosphate (RuBP)** using ATP to allow the cycle to continue.
55
What is the function of the **reaction center** in a photosystem?
It is the functional center of the photosystem **where the light reactions of photosynthesis begin**.
56
What is the key to **creating sugars** in the Calvin cycle?
Carbon fixation
57
What is the photosynthesis **equation** to make glucose?
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2 | (Water + carbon dioxide + sunlight = glucose + oxygen)
58
What is the process called that completes the second half of photosynthesis by **taking in carbon dioxide and producing glucose**?
Calvin cycle
59
What is the role of sunlight in the **photosystem II** during the light-dependent reactions?
It strikes the pigment molecules on the surface of the thylakoid, exciting electrons and raising them to a **higher energy level**, while photolysis occurs. ## Footnote Photosystem 2 is the first step of photosynthesis.
60
Where are **photosystems** found?
* In the **thylakoid membrane** of the chloroplast in plants and algae. * In the **cell membrane** of photosynthetic bacteria.
61
What is **cytoplasm** in cells?
A **gel-like filler** in cells where various cellular activities take place.
62
What is a **redox reaction**?
A reaction involving the **losing and gaining of electrons**. ## Footnote It is essential for the electron transport chain.
63
What are the **products** of cellular respiration?
* ATP * Water * Carbon dioxide
64
What are the **stages** of cellular respiration?
1. Glycolysis 2. Citric acid cycle 3. Electron transport chain ## Footnote Glycolysis and the Citric Acid Cycle together are part of what is known as the "Krebs Cycle."
65
What are the two **types** of cellular respiration processes?
* **Aerobic respiration** (in the presence of oxygen) * **Anaerobic respiration** (in the absence of oxygen)
66
What are the two primary **phases** of cellular respiration?
* Anaerobic phase (e.g., Glycolysis in the cytoplasm) * Aerobic phase (e.g., Krebs Cycle + ETC in mitochondria) ## Footnote The Krebs cycle includes glycolysis and the citric acid cycle.
67
What is **cellular respiration**?
The metabolic process by which living cells acquire chemical energy from food.
68
What is the **chemical formula** for cellular respiration?
C6H12O6 + 6O2 + 32 ADP + 32 Pi → 6CO2 + 6H2O + 32 ATP
69
Where does cellular respiration occur **if oxygen is present**?
Mitochondria ## Footnote Mitochondria are factories in cells that break down food and create energy.
70
What is **glycolysis**?
Glucose is **converted to pyruvate**, and energy that is released is converted to **2 ATP**.
71
Where does **Glycolysis** take place within plant and animal cells?
Cytoplasm
72
What is the **Krebs cycle**?
Also known as the citric acid cycle, is the conversion of pyruvate into high-energy intermediates that will eventually be used to create energy for the cell.
73
Where does the **Krebs Cycle/Citric Acid Cycle** occur?
Mitochondria
74
What are the **products** of **Glycolysis**?
* Two pyruvate * Two NADH * Two net ATP
75
What are the **products** of the **Krebs cycle**?
* Acetyl-CoA * Carbon dioxide * NADH
76
What are the **starting materials** for the **Krebs cycle**?
* Pyruvate, * NAD+, and * coenzyme A
77
What are the **starting materials** of **Glycolysis**?
* Glucose * ATP * ADP (adenosine diphosphate) * NAD+ * phospate
78
What are the total products of glycolysis and the citric acid cycle **combined**?
Four net ATP molecules and six carbon dioxide molecules.
79
What may follow glycolysis in **anaerobic organisms**?
fermentation ## Footnote Fermentation will complete the phosphorylation of ADP in anaerobic respiration.
80
What is the **electron transport chain**?
The final step of cellular respiration that **converts food into chemical energy (ATP)**.
81
What are the **products** of the **electron transport chain**?
* NAD+ * FAD * water * ATP
82
What are the **reactants** of the **electron transport chain**?
* NADH * FADH2 * Protons * ADP * Oxygen
83
What happens in the **electron transport chain**?
1. Electrons are transferred from one protein complex to another on the inner membrane of the mitochondria. 2. Protons are pumped across the membrane, creating a proton gradient. 3. Protons then flow through the channel protein, ATP Synthase, which phosphorylates ADP to produce ATP.
84
What is the **final electron acceptor** of the electron transport chain?
Oxygen ## Footnote As it accepts electrons, it splits and binds to hydrogen ions in the intracellular environment to become water.
85
Where does the **electron transport chain** take place?
On the **inner membrane** of the mitochondria.
86
What happens to **pyruvate** in alcoholic fermentation?
It is converted to a 2-carbon molecule called acetaldehyde.
87
What is **alcoholic fermentation**?
A process where microorganisms like yeast convert glucose to carbon dioxide, ethanol, and energy, using ethanol dehydrogenase and pyruvate decarboxylase enzymes. ## Footnote Can be used for: * Production of alcoholic beverages like wine and beer. * Ethanol fuel production. * Baking industry for dough rising. * Tanning leather and making it soft.
88
What is **fermentation**?
A chemical process where **sugar is broken down in the absence of oxygen**.
89
What is **lactic acid** fermentation?
The process in which glucose is transformed to pyruvate and NADH. Then, the pyruvate is changed into lactate (lactic acid) while producing two ATP. ## Footnote Lactic acid fermentation is a metabolic process that occurs in muscle cells and some bacteria, converting glucose into lactic acid.
90
What is **produced** in alcoholic fermentation?
* Ethanol * Carbon dioxide * NAD+
91
What is the main **difference** between lactic acid fermentation and alcoholic fermentation?
* The end product of lactic acid fermentation is **lactic acid**. * The end product of alcoholic fermentation is **ethanol and carbon dioxide**.
92
What is the **net yield** of cellular respiration in **anaerobic** respiration?
2 ATP
93
What are the three types of **passive transport**?
* Simple diffusion * Osmosis * Facilitated diffusion ## Footnote These processes do not require energy as substances move down their concentration gradient.
94
Who proposed the **chemiosmotic theory**?
Peter D. Mitchell ## Footnote He was a British biochemist who proposed that ATP synthesis is coupled to an electrochemical proton gradient.
95
What is **chemiosmosis**?
The movement of ions from **high concentration to low concentration** through a selectively permeable membrane. ## Footnote Chemiosmosis depends on the diffusion principle.
96
What is the **proton motive force**?
The energy generated by the **transfer of protons (H+)** across an energy-transducing membrane. ## Footnote This force drives ATP synthesis in chemiosmosis.
97
Where does chemiosmosis occur in **prokaryotic cells**?
In the **cell membrane** ## Footnote Prokaryotes lack mitochondria and chloroplasts.
98
What are the **raw ingredients** for chemosynthesis?
* Oxygen * Carbon dioxide * Inorganic molecule (e.g., hydrogen sulfide)
99
What is **chemosynthesis**?
A process whereby a carbon molecule is converted into a sugar-based food source through the oxidation of inorganic molecules as a source of energy. ## Footnote Occurs in bacteria and archaea.
100
What is **oxidation** in chemosynthesis?
A process where molecules or atoms **lose their electrons** during a reaction.
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