Praxis (5236) - Biology > 2A4 Energy in Organisms > Flashcards

2A4 Energy in Organisms Flashcards

Understand how ATP is created, utilized, and transferred in organisms. Describe photosynthesis, aerobic and anaerobic respiration, and chemosynthesis. (93 cards)

Study These Flashcards
1
Q

What does the term ‘metabolism’ refer to?

A

The sum of all an organism’s chemical reactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two types of metabolic pathways?

A
  • Catabolic pathways
  • Anabolic pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
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 acid cycle (Krebs cycle), Glycolysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

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

A

Metabolic pathways chart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do enzymes do in metabolic pathways?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the energy used by all living organisms?

A

Adenosine triphosphate

(ATP)

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List the three sections of the ATP molecule.

A
  • Sugar molecule called ribose
  • Base known as adenine
  • Group of three phosphates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the chemical formula for ATP?

A

C10H16N5O13P3

  • 10 Carbon
  • 16 Hydrogen
  • 5 Nitrogen
  • 13 Oxygen
  • 3 Phosphorus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is ATP found in animal cells?

A

In the cytoplasm and mitochondria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is ATP found in plant cells?

A
  • Mitochondria
  • Chloroplasts
  • Cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is cytoplasm in cells?

A

A semi-fluid substance inside cells that holds organelles and supports chemical reactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the low-energy molecule formed when ATP loses a phosphate?

A

ADP

(adenosine diphosphate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is used to convert ADP back into ATP?

A

Phosphorylation

This is the process of adding a phosphate group to a molecule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is cellular respiration?

A

The metabolic process by which living cells acquire chemical energy from food.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the chemical formula for cellular respiration?

A

C6H12O6 + 6O2 + 32ADP → 6H2O + 6CO2 + 32ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the products of cellular respiration?

A
  • ATP
  • Water
  • Carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the total number of ATP molecules produced during the entire process of cellular respiration?

A

32

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does cellular respiration occur if oxygen is present?

A

Mitochondria

Mitochondria are factories in cells that break down food and create energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the stages of cellular respiration?

A
  1. Glycolysis
  2. Citric acid cycle
  3. Electron transport chain

Glycolysis and the Citric Acid Cycle together are part of what is known as the “Krebs Cycle.”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the two primary phases of cellular respiration?

A
  • Krebs Cycle
  • Electron transport chain (ETC)

The Krebs cycle includes glycolysis and the citric acid cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the two **types** of cellular respiration processes?
* **Aerobic respiration** (in the presence of oxygen) * **Anaerobic respiration** (in the absence of oxygen)
26
What is **photosynthesis**?
Uses light energy to convert carbon dioxide and water into carbohydrates and oxygen within chloroplasts.
27
What is the photosynthesis **equation** to make glucose?
6𝐻2𝑂+6𝐶𝑂2+𝑠𝑢𝑛𝑙𝑖𝑔ℎ𝑡−−>𝐶6𝐻12𝑂6+6𝑂2 ## Footnote Water + carbon dioxide + sunlight = glucose + oxygen
28
What are the **reactants** needed for photosynthesis to occur?
* Water * Carbon dioxide * Light
29
What are the **products** created during photosynthesis?
* Oxygen * Glucose
30
**Where** does photosynthesis occur in plants and algae?
In organelles called **chloroplasts**.
31
What are the **two reactions** that take place during photosynthesis?
* Light-dependent reactions * Light-independent reactions ## Footnote The light-independent reaction is also known as the Calvin cycle.
32
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
33
What are the **products** of the light-dependent reaction in photosynthesis?
* Oxygen * ATP * NADPH
34
What is **reduced to NADPH** during the light-dependent reactions in photosynthesis?
NADP+
35
What is a **photosystem**?
**Functional units for photosynthesis**, containing chlorophyll molecules, accessory pigments, and proteins. ## Footnote Organized into 2 identified systems: Photosystem I and Photosystem II
36
What is the **primary pigment** in plants responsible for capturing light energy?
Chlorophyll
37
Where are **photosystems** found?
* In the **thylakoid membrane of the chloroplast** in plants and algae. * In the **cell membrane** of photosynthetic bacteria.
38
What are the **two main photosystems** in photosynthesis?
* Photosystem I * Photosystem II ## Footnote Photosystems I and II are utilized in light-dependent reactions.
39
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**.
40
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 II is the first step of photosynthesis.
41
What is the process in which sunlight catalyzes the **splitting of water** into separate hydrogen and oxygen atoms called?
Photolysis
42
What does **Photosystem I** do?
Captures high energy electrons, and passes them down an electron transport chain to produce NADPH. ## Footnote Occurs AFTER photosystem 2.
43
What is the process called that completes the second half of photosynthesis by **taking in carbon dioxide and producing glucose**?
Calvin cycle
44
What are the **reactants** of the Calvin cycle?
* CO2 * ATP * NADPH
45
What are the **products** of the Calvin cycle?
* Glyceraldehyde 3-phosphate (G3P) * ADP * NADP+
46
What are the **three main stages** of the Calvin cycle?
1. Carbon fixation 2. Reduction 3. Regeneration
47
What is the key to **creating sugars** in the Calvin cycle?
Carbon fixation
48
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.
49
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.
50
What is the enzyme that joins **carbon dioxide with RuBP** in the Calvin cycle?
RuBisCo ## Footnote This process is going to create 6 molecules of glyceraldehyde-3-phosphate (G3P).
51
How many molecules of G3P are needed to produce one molecule of glucose in the Calvin cycle?
Six
52
What is **glycolysis**?
Glucose is converted to pyruvate, and energy that is released is converted to 2 ATP. | A catabolic pathway.
53
**Where** does Glycolysis take place within plant and animal cells?
Cytoplasm
54
What are the **starting materials** of Glycolysis?
* Glucose * ATP * ADP (adenosine diphosphate) * NAD+ * a phosphate molecule
55
What is the coenzyme in cells that collects electrons and carries them to another location?
Nicotinamide adenine dinucleotide | (NAD+)
56
What is the **role of coenzyme NAD+** in glycolysis?
It picks up an electron when it is reduced to become **NADH**.
57
What are the **products** of Glycolysis?
* Two pyruvate * Two NADH * Two net ATP
58
What is the other name for the **Citric Acid Cycle**?
Krebs Cycle and Tricarboxylic Acid Cycle
59
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.
60
**Where** does the Krebs Cycle/Citric Acid Cycle occur?
In the mitochondria.
61
What are the **starting materials** for the **Krebs cycle**?
* Pyruvate * NAD+ * coenzyme A
62
What are the **products** of the **Krebs cycle**?
* 3 NADH * 1 FADH₂ * 1 ATP (or GTP) * 2 CO₂ ## Footnote Each turn of the Krebs cycle begins with acetyl-CoA combining with oxaloacetate. Oxaloacetate is regenerated at the end of the cycle, allowing it to continue.
63
What are the total products of **glycolysis and the citric acid cycle combined**?
Four net ATP molecules and six carbon dioxide molecules.
64
What is the **electron transport chain**?
The final step of cellular respiration that **converts food into chemical energy (ATP)**.
65
Where does the electron transport chain take place?
On the **inner membrane** of the mitochondria.
66
How much ATP is produced by the electron transport chain in aerobic cellular respiration?
It produces **28 molecules of ATP**.
67
What are the **reactants** of the **electron transport chain**?
* NADH * FADH2 * Protons * ADP * Oxygen
68
What are the **products** of the **electron transport chain**?
* NAD+ * FAD * water * ATP
69
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.
70
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.
71
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.
72
What is the primary process that **results in ATP production** during the electron transport chain?
Chemiosmosis
73
What are the two connected processes involved in **oxidative phosphorylation**?
* Electron transport chain * Chemiosmosis
74
What is the main function of **oxidative phosphorylation**?
To create a large number of ATP molecules.
75
Where does oxidative phosphorylation occur?
Within the **mitochondrion**.
76
What are the **steps** of oxidative phosphorylation?
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.
77
What **enzyme** is responsible for the gradient-driven **phosphorylation of ADP into ATP**?
ATP synthase ## Footnote It uses the electrochemical gradient as power and is made up of an electric motor and a chemical motor.
78
What are the **products** of oxidative phosphorylation?
* Adenosine triphosphate * NAD+ * FAD * Water
79
How many molecules of **ATP** are produced by oxidative phosphorylation from each molecule of glucose?
Approximately 34 ## Footnote ATP synthesis occurs in and across the mitochondrial membrane.
80
What may follow glycolysis in **anaerobic organisms**?
Fermentation ## Footnote Fermentation will complete the phosphorylation of ADP in anaerobic respiration.
81
What is **fermentation**?
A chemical process where **sugar is broken down** in the **absence of oxygen**.
82
What is the net yield of cellular respiration in **anaerobic respiration**?
2 ATP
83
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
84
What is **produced** in alcoholic fermentation?
* Ethanol * Carbon dioxide * NAD+
85
What happens to **pyruvate** in alcoholic fermentation?
It is converted to a 2-carbon molecule called acetaldehyde.
86
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.
87
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**.
88
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.
89
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.
90
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.
91
What is **oxidation** in chemosynthesis?
A process where molecules or atoms **lose their electrons** during a reaction.
92
What do photosynthesis and chemosynthesis both **produce**?
Food energy (glucose) and a byproduct.
93
What are the **raw ingredients** for chemosynthesis?
* Oxygen * Carbon dioxide * Inorganic molecule (e.g., hydrogen sulfide)
Praxis (5236) - Biology
flashcards
Decks in class (39)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions