cellular respiration and photosynthesis

What is the primary biological purpose of cellular respiration?

To harvest energy from organic molecules and convert it into ATP for cellular work

What are the four sequential stages of aerobic cellular respiration?

Glycolysis

Pyruvate oxidation

Citric acid cycle (krebs cycle)

Electron transport chain and chemiosmosis

Where in the cell does glycolysis occur?

In the cytoplasm

What is the primary carbohydrate input required for glycolysis?

Glucose

What are the net molecular products generated from one molecule of glucose during glycolysis?

2 pyruvate, 2 net ATP, and 2 NADH

Does glycolysis require oxygen to proceed?

No

What kind of process is the glycolysis?

An anaerobic process

Is glycolysis an endergonic or exergonic pathway?

Exergonic

Why is glycolysis an exergonic pathway?

It releases free energy

What is the fate of pyruvate produced by glycolysis?

It is transported into the mitochondrial matrix to undergo pyruvate oxidation

Why must NAD+ be continually regenerated during cellular respiration?

To serve as an electron acceptor so that metabolic breakdown pathways can continue running

What key 2-carbon molecule is formed during pyruvate oxidation?

Acetyl- COA

Where does pyruvate oxidation take place in eukaryotic cells?

In the mitochondrial matrix

Where does the citric acid cycle take place in the eukaryotic cell?

In the mitochondrial matrix

How many times does the citric acid cycle turn for every glucose molecule degraded?

Twice

Why does the citric acid cycle turn twice?

Because one glucose molecule yields two pyruvate molecules, forming two acetyl-coa molecules

How many ATP molecules are directly produced by the citric acid cycle?

2 ATP molecules

What electron carriers are generated by the citric acid cycle per glucose molecule?

6 NADH and 2 FADH2

What inorganic gas is released as a byproduct during the citric acid cycle?

Carbon dioxide

Where is the electron transport chain located in eukaryotic cells?

In the inner mitochondrial membrane or cristae

What electron carriers feed high-energy electrons into the electron transport chain?

10 NADH and 2 FADH2

What process utilizes a proton electrochemical gradient to synthesize ATP during cellular respiration?

Chemiosmosis

Which membrane enzyme produces ATP during chemiosmosis?

ATP synthase

What is the gross ATP output versus the net ATP yield of glycolysis?

Gross output 4 ATP; Net yield: 2 ATP

How many total NADH molecules are produced across all stages of respiration per glucose?

10 NADH

How many NADH molecules are from glycolysis?

2 NADH molecules

How many NADH molecules are from pyruvate oxidation?

2 NADH molecules

How many NADH molecules are from citric acid cycle?

6 NADH molecules

What is the maximum theoretical ATP yield generated solely by the electron transport chain per glucose?

34 ATP molecules

What is the maximum theoretical total ATP yield per glucose molecule during aerobic respiration?

38 ATP molecules

How does anaerobic respiration differ from fermentation?

Anaerobic respiration uses an electron chain, whereas fermentation operates without an electron transport chain

What are two groups of prokaryotes that utilizes anaerobic respiration?

Methanogens and sulfur prokaryotes

What are the primary end products of ethanol fermentation?

Ethanol and carbon dioxide

What is the end product of lactic acid fermentation?

Lactic acid

How do cellular respiration and photosynthesis compare regarding cellular organelles?

Cellular respiration occurs only in mitochondria, and photosynthesis occurs in chloroplasts

Where does cellular respiration occur?

In the mitochondria

Where does photosynthesis occur?

In the chloroplasts

What is the main photosynthetic pigment in green plants?

Chlorophyll a

What are three classes of accessory pigments involved in light absorption?

Chlorophyll b, carotenoids, and phycobiloproteins

Where do the light-dependent reactions of photosynthesis take place?

In the thylakoid membranes

Which photosystems participate in noncyclic photophosphorylation?

Both photosystem II and plotosystem I

What products are generated by noncyclic photophosphorylation?

ATP, NADPH, and O2

What molecule provides replacement electron to photosystem II during noncyclic electron flow?

Water

Which photosystem is involved in cyclic photophosphorylation?

Photosystem I only

What energy compound is exclusively produced by cyclic photophosophorylation?

ATP

How is ATP synthesized during the light-dependent reactions of photosynthesis?

Via chemiosmosis

Where do the light-independent reactions/ Calvin cycle take place?

In the stroma of the chloroplast

What enzyme catalyzes carbon fixation in the Calvin cycle?

Rubisco

What 5-carbon compound accepts CO2 during initial fixation in the Calvin cycle?

Ribose 1.5 bisphosphate/RuBP

What role does NADHPH play during the Calvin cycle?

Acts as a reducing agent, and donates high-energy elections during the reduction phase

What carbohydrate molecule is directly exported from the Calvin cycle?

Glyceraldehyde 3-phosphate

How many turns of the Calvin cycle produce one net molecule of G3P?

3 turns

How many turns of one Calvin cycle and net G3P molecules are required to form one glucose molecule?

6 turns of the Calvin cycle and 2 G3P molecules

What are the 3 main sequential phases of the Calvin cycle?

Carbon fixation

Reduction

Regeneration of RuBP

What are the key molecular inputs of chloroplast bioenergetics?

CO2, H20, and light energy

What are the products of chloroplast bioenergetics?

Glucose and O2

What are the key molecular inputs of mitochondrial bioenergetics?

Glucose and O2

What are the products of mitochondrial bioenergetics?

CO2, H20, and ATP

What process occurs when rubisco binds oxygen instead of carbon dioxide?

Photorespiration

Why is photo respiration considered wasteful to plants?

It consumes and releases without reducing sugar

What environmental conditions is photo respiration most produced?

Hot, dry conditions

How do c4 plants minimize photorespiration?

By spatially separating carbon fixation from the Calvin cycle

How do CAM plants minimize photorespiration?

By temporally separating carbon fixation from the Calvin cycle?

What are two common crop plant examples that utilize the C4 photosynthetic pathway?

Corn and sugarcane

What are two plant examples that utilize the CAM photosynthetic pathways?

Caca and pineapples

What is the overall chemical equation for aerobic cellular respiration?

C6 H12 O2+ 6O2——> 6CO2+6H2O+ATP

What molecules are involved in cellular respiration?

ATP and NADH and FADH 2

Thylakoid

Flattened internal membrane sacs ( where light reactions happens)

Grana

Stacks of thylakoids

Stroma

The semi-liquid fluid surrounding thylakoids ( where the Calvin cycle happens)

Pigments

Molecules that absorb light energy

Chlorophyll a

The main photosynthetic pigment; directly converts ight energy to chemical energy

Chlorophyll b

Accessory pigment that complements chlorophyll a

Carotenoids and phycobiliproteins

Scrap accessory pigments that absorb wider wavelengths and protect cells from excess light damage

Photosystems

Clusters of chlorophyll and accessory pigments organized in the thylakoid membrane to trap light energy

Photorespiration

It wasteful metabolic pathway that occurs in plants when the enzyme rubisco accidentally binds to oxygen instead of carbon dioxide