Cell Respiration and Photosynthesis

Question 1

What is metabolism?

Answer 1

The chemical reactions of photosynthesis and cellular respiration. They need reactants and produce metabolic products.

Question 2

What does anabolic mean?

Answer 2

This is the building of complex molecules from simpler molecules, which requires energy. This is a part of metabolism.

Question 3

What does catabolic mean?

Answer 3

This is when complex molecules are broken down into simpler molecules, which releases energy. This is a part of metabolism.

Question 4

What are redox reactions?

Answer 4

These are reactions where electrons are transferred from one reactant to another, and they form a bond. The reactant that loses an electron is oxidized. The reactant that gains an electron is reduced.

Question 5

What is oxidation?

Answer 5

This is when an atom loses an electron by giving it to another atom. The atom that accepts the new electron is called the reducing agent. It will contain less energy because it has fewer electrons.

Question 6

What is reduction?

Answer 6

This is when an atom gains an electron by taking it from another atom. The atom that gives the new electron is called the oxidizing agent. It will contain more energy as it has more electrons.

Question 7

What are protons?

Answer 7

This is used for H+ ions.

Question 8

What is photosynthesis?

Answer 8

The process by which plants and some other organisms convert carbon dioxide, water, and light energy, typically from the sun, into chemical energy. This is all converted into glucose, a type of sugar, and oxygen. This is done in the chloroplasts. The formula used is 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2.

Question 9

What are light-dependent reactions?

Answer 9

Also called the Krebs cycle, these are reactions that convert light energy into chemical energy. This process occurs in the thylakoid membranes of the chloroplasts. These reactions use light energy to split water molecules, releasing oxygen and energy (ADP and NADPH) and then use the light-independent reactions to produce sugar.

Question 9

What are light-independent reactions?

Answer 9

Also called the Calvin cycle, this happens after the Krebs Cycle. The reactions here use the stored chemical energy from the Krebs Cycle to fix CO2 into a more usable organic form. This fixed CO2 can be used to make glucose. These happen in the stroma, the fluid that surrounds the chloroplasts.

Question 10

What is aerobic cellular respiration (three steps)?

Answer 10

This is the process by which cells produce energy (ATP) from glucose and oxygen. It has three steps.
1. Glycolysis, where the glucose in the cytoplasm is broken down, which produces ATP, NADH, and pyruvate.
2. Krebs cycle, when the mitochondrial matrix breaks down pyruvate further, producing more ATP, NADH, and FADH2.
3. The electron transport chain and chemiosmosis utilize NADH and FADH2 to create a proton gradient by pumping protons into the mitochondrial membrane. The protons, now concentrated, will flow back across the membrane into the mitochondrial matrix, which drives ATP synthase, producing a large amount of ATP.

Question 10

What is the mitochondria?

Answer 10

The powerhouse of the cell. This oxidizes glucose and uses the energy released to synthesize ATP, consuming oxygen in the process. Glucose is oxidized and oxygen is reduced.

Question 11

What is the outer mitochondrial membrane?

Answer 11

This is a permeable barrier used in cellular respiration that allows essential molecules, ions and proteins to pass through it, which exchanges materials between the mitochondria and cytoplasm.

Question 12

What is the cristae?

Answer 12

These are folded inner membrane structures of the mitochondria. They increase the surface area of the inner membranes, which is crucial for ATP production, as there is more surface area for the electron transport chain and ATP synthase.

Question 13

What is the matrix?

Answer 13

This is a part of the mitochondria that contains fluid. It is where the Krebs cycle takes place. This fluid is enclosed in the inner membrane and contains enzymes, DNA, and other components for cellular respiration. The enzymes are used for the Krebs cycle. FADH only shows up in the matrix during the Krebs cycle.

Question 14

What is anaerobic respiration?

Answer 14

This is also called fermentation, and it is when organisms generate ATP without using oxygen. Glucose and other organic molecules are broken down to release energy. It is less efficient than aerobic respiration.

Question 15

What are the types of fermentation (that we need to know for IB)?

Answer 15

Alcoholic fermentation which produces ethanol and CO2 from sugars. Yeast does this.
Lactic acid fermentation is done in muscle cells when there is no oxygen present. It produces lactic acid.

Question 16

What are electron carriers?

Answer 16

These are special molecules that help transfer electrons around for cellular processes. They play a crucial role in redox reactions and are a key part of the electron transport chain. They can take electrons from one molecule and deliver them to another, reducing and oxidizing them. NAD+ and FAD are primary electron carriers. NADH and FADH2 both donate electrons to the electron transport chain.

Question 17

What is glycolysis?

Answer 17

This occurs in the cytoplasm of the cell, which is used to produce ATP. The process oxidizes the 6-carbon glucose into two molecules of 3-carbon pyruvate. This process creates 4 ATP molecules and 2 NADH molecules. In the presence of oxygen, pyruvate breaks down into acetyl-CoA, which enters the citric acid cycle and the electron transport chain in the mitochondria, leading to a very high ATP yield. Without oxygen, pyruvate will be converted into lactate and give a lesser amount of ATP. The process has a net gain of 2 ATP.

Question 18

Which co-enzymes are used in glycolysis?

Answer 18

NAD+ and ATP are both co-enzymes used in glycolysis. They are crucial for energy production and electron transfer. NAD+ accepts both electrons and hydrogen ions during the oxidation of glucose in glycolysis.

Question 19

What is pyruvate?

Answer 19

Pyruvate is the end product of glycolysis, which breaks down glucose into smaller molecules. Pyruvate decarboxylation happens, where pyruvate loses a carbon dioxide molecule, and is then coupled with coenzyme A. This reaction happens in the mitochondrial matrix. When CO2 is removed, energy is released as electrons. This energy is transferred into NAD+ and NADH. NADH will bring electrons into the electron gradient. When pyruvate turns into acetyl-CoA, it enters the Krebs cycle.

Question 20

What is aerobic respiration?

Answer 20

This is a cellular process that utilizes oxygen to convert glucose and other nutrients into ATP, CO2 and water, releasing energy in the process. It is everything from glycolysis, then the Krebs cycle, and then the electron transport chain. It produces a significant amount of ATP and happens in the mitochondria.

Question 21

What is the Pre-Krebs/Links cycle?

Answer 21

This is what bridges glycolysis and the Krebs cycle. It converts pyruvate into acetyl-CoA, which enters the Krebs cycle.

Question 22

What is coenzyme A?

Answer 22

This is a special enzyme that attaches to pyruvate so that pyruvate can enter the Krebs cycle.

Question 23

What is the Krebs cycle?

Answer 23

It's a cycle that produces energy, beginning with acetyl-CoA, which is converted into ATP. It extracts electrons from molecules and transfers them into electron carriers, such as NADH and FADH2, which are used in the electron transport chain. It releases CO2 as a waste product and takes place in the matrix of the mitochondria in eukaryotic cells and in the cytoplasm of prokaryotic cells.

Question 24

What is decarbonization?

Answer 24

This is a carbon reaction that occurs when a carbon group is removed from a molecule, resulting in the release of CO2. This process occurs in the creation of acetyl-CoA.

Question 25

What is the electron transport chain?

Answer 25

These are protein complexes embedded in the inner mitochondrial membrane which facilitate the transport of electrons from NADH and FADH2 to oxygen. This process generates a protein gradient across the membrane, used to synthesize ATP through oxidative phosphorylation. After donating electrons, electron carriers return to their original, oxidized forms.

Question 26

What is a proton pump?

Answer 26

This is a protein which transports hydrogen ions (protons) across the membrane of the mitochondria, creating a concentration gradient. The flow of electrons through the electron transport chain drives the pumping of these protons. This gradient is what drives ATP production.

Question 27

What is chemiosmosis?

Answer 27

This is the movement of protons from the mitochondrial matrix into the intermembrane space, creating a concentration gradient. ATP synthase acts as a channel for these protons to flow back across the membrane. As those protons move through the ATP synthase, it uses them to convert ADP and P into ATP.

Question 28

What is ATP synthase?

Answer 28

This is an enzyme that acts as a sort of rotary motor that synthesizes ATP. It uses the proton gradient across a membrane to power this ATP synthesis. Chemiosmosis is where the energy for this process comes from.

Question 29

What is oxidative phosphorylation?

Answer 29

This is the process by which cells produce ATP, the main energy currency of the cell.

Question 30

What is light energy?

Answer 30

This is a form of electromagnetic radiation. It is made of tiny packets of energy, called photons. They travel in waves, but behave as particles when in the form of photons.

Question 31

What are colour wavelengths?

Answer 31

The light wavelengths are organized from red to violet, in rainbow order. The red wavelengths are the longest, and the violet wavelengths are the shortest. Shorter wavelengths have higher frequencies and more energy than longer wavelengths.

Question 32

What is an action spectra graph?

Answer 32

It depicts the effectiveness of different wavelengths of light on specific biological processes. It's used to determine which wavelengths of light are the most useful for any given reaction. It is often used to determine the rate of photosynthesis at different wavelengths of light.

Question 33

What is chemical energy?

Answer 33

This is energy stored in the bonds of chemical compounds, which is released during a chemical reaction.

Question 34

What are the chloroplasts?

Answer 34

These are organelles where photosynthesis takes place. They are found in the mesophyll, the inner tissue of plant leaves. They contain a double membrane, including the thylakoid membrane and a fluid-filled space called the stroma. They contain chlorophyll, a pigment that captures light and is responsible for converting CO2 and water into glucose.

Question 35

What are the grana?

Answer 35

This is the name for stacks of thylakoids. They are found in the chloroplasts. Thylakoids are responsible for photosynthesis.

Question 36

What is the thylakoid membrane?

Answer 36

This is a specialized membrane system within chloroplasts. They form a continuous network that encloses an internal space called the thylakoid lumen. It is the site of photosynthesis.

Question 37

What is the thylakoid lumen?

Answer 37

This is a space in the thylakoid membrane that is crucial to photosynthesis. It accumulates protons, creating a proton gradient that drives ATP synthase. This is how light energy is converted into chemical energy. It also houses ions, enzymes, and proteins.

Question 38

What is chlorophyll?

Answer 38

This is a green pigment found in plants that absorbs light energy and converts it into chemical energy. It absorbs red and blue light, reflecting green light.

Question 39

How does chlorophyll convert light energy into chemical energy (steps)?

Answer 39

1. PSI absorbs light energy, and all the electrons in the chlorophyll become energized. 2. These energized electrons jump to a higher energy level 3. They are then transferred by PSI to carrier molecules, beginning the electron transport chain. 4. The chlorophyll uses PSII, which takes electrons from water, releasing oxygen as a byproduct. 5. These electrons replace the ones it lost, and the process begins again.

Question 40

What is chromatography?

Answer 40

A technique used to separate different photosynthetic pigments from plant leaves, revealing the variety of colours present in the leaves, even those hidden by the green chlorophyll. This helps identify the pigments involved in capturing light to be used in photosynthesis.

Question 41

What is photosystem 1 (PSI)?

Answer 41

This is a special type of chlorophyll that absorbs light and transfers energized/excited electrons to NADP+ to create NADPH. It is a light driven protein pump that uses the energy of photons (light) to move electrons across the thylakoid membrane, where they can be used to make NADPH, which is used in the Calvin cycle.

Question 42

What is photosystem 2 (PSII)?

Answer 42

This is a protein complex that is involved in the light-dependent reactions of photosynthesis. It captures light energy and uses it to extract electrons from water, which are used to replace electrons lost by chlorophyll during photosynthesis.

Question 43

What is the absorption spectra?

Answer 43

This is a graph showing the absorption of different wavelengths of light by a pigment, mapping which wavelengths of light the pigment absorbs. It’s a visual representation of which wavelengths a pigment uses to capture light energy.

Question 44

What is the stroma?

Answer 44

This is a fluid-filled space within the chloroplasts. It surrounds the thylakoids and grana. It is the site where the Calvin cycle takes place.