Ch. 6 How Cells Harvest Chemical Energy Flashcards Preview

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Flashcards in Ch. 6 How Cells Harvest Chemical Energy Deck (52):
1

Aerobic

Containing/requiring molecular oxygen

2

Anaerobic

Lacking/not requiring molecular oxygen

3

Cellular Respiration

Aerobic harvesting of energy from food molecules
- energy releasing chemical breakdown of food molecules, such as glucose, and the storage of potential energy in a form that called can use to perform work

4

What are the three phases of cellular respiration?

1) Glycolysis
2) Krebs Cycle
3) Electron Transport Chain & Chemiosmosis

5

Why can't the cell harvest all of the energy in a useable form?

40% of glucose is turned into ATP and the rest is converted to heat.

6

Redox Reaction

Oxidation reduction
- describes movement of electrons from donor molecules to an acceptor molecule

7

Oxidation

Loss of electrons from a substance involved in a redox reaction

8

Reduction

Gain of electrons by a substance involved in a redox reaction

9

What does oxidation and reduction accompany each other?

Always together because electron transfer needs both donor and acceptor.

10

Dehydrogenase

An enzyme that catalyzes a chemical reaction during which one or more hydrogen atoms are removed from a molecules

11

What is NAD+?

Nicotinamide adenine dinucleotide
- a coenzyme that assists enzymes by converting electrons (from hydrogen atoms) during the redox reactions of cellular metabolism
- oxidized molecule, ready to pick up electrons

12

Electron Carrier

A molecule that conveys electrons within a cell
- make up the electron transport chain
- shuttles electrons during redox reactions that release energy for ATP synthesis

13

What keeps electrons of the carrier molecules moving?

Affinity for electrons.

14

Electron Transport Chain

Synthesizes ATP by the process of chemiosmosis.
- inner membrane of mitochondria, thylakoid of chloroplast, plasma membrane of prokaryotes

15

Chemiosmosis

The production of ATP using the energy of H+ gradients across membranes to phosphorylate ADP
- powers most of the ATP synthase

16

ATP Synthase

Series of protein complexes embedded in the inner membrane of mitochondria loaded with enzymes for phosphoration of ADP to ATP
- provides the port through which H+ diffuse (uses PE of concentration gradient)

17

Substrate-level Phosphorylation

The formation of ATP occurring when an enzyme transfers a phosphate group from an organic molecule to ADP
- occurring because bond holding phosphate group in substrate molecule is less stable than ATP bond

18

Glycolysis

"splitting of sugar"
Multistep chemical breakdown of a molecule of a glucose into two molecules of pyretic acid.
- first step of of cellular respiration
- occurs in cytoplasmic fluid
- exergonic

19

Krebs Cycle

Metabolic cycle fueled by acetyl CoA formed after glycolysis in cellular respiration
- chemical reactions complete the metabolic breakdown of glucose molecules to carbon dioxide
- occurs in matrix of mitochondria and supplies most of the NADH molecules that carry energy to electron transport carriers
- exergonic

20

What are the three steps of cellular respiration?

1) Glycolsysis
2) Krebs Cycle
3) Electron Transport

21

What are the two carriers of electron transport chain?

NADH (NAD+) and FAD (FADH2)

22

Intermediate

A compound formed between initial reactant in metabolic pathway and the final product

23

How many steps are there in glycolysis?

9 steps
1 - 4) Preparatory & Consumer Energy Phase [consumes 2 ATP]
5 - 9) Energy Payoff Phase [Yields 4 ATP]

24

What is the net gain of glycolysis?

2 ATP molecules

25

Acetyl CoA

High energy fuel molecule for Krebs Cycle

26

What are three ways poisons block cellular respiration?

1) Blocks the electron transport chain
2) Inhibits ATP synthesis
3) Uncouplers makes membrane of mitochondrion leak H+

27

Alcoholic Fermentation

Production of ethanol from glucose in which CO2 removed from pyruvic acid & NADH is oxidized to NAD+

28

Lactic Acid Fermentation

Lactic acid is produced when NADH from glycolysis is oxidized

29

Strict anaerobic

Require anaerobic conditions
- O2 would mean poison

30

Facultative anaerobe

Microorganisms that makes ATP by aerobic respiration if O2, if not then fermentation

31

Respiration

The exchange of O2 and CO2 between organism and environment
- General/External
- Cellular respiration/Internal

32

What is general respiration?

Oxygen from air to lungs to blood, CO2 blood to lungs to air
- breathing

33

What is cellular respiration (internal)?

It is the energy releasing break down of food molecules in cells.
- O2 + glucose -> H20 + CO2 + Energy
- occurs in mitochondria

34

What is metabolism? 2 types?

All chemical changes in a cell.
1) Catabolism
2) Anabolism

35

Catabolism

Breakdown of molecules, releases energy
- ex. cellular respiration

36

Anabolism

Build molecules, stores energy

37

Do plant cells go through cell respiration?

YES

38

What is the equation for cellular respiration?

C6H12O6 + 6O2 -> 6H20 + 6CO2 + 38 ATP

39

Why are fats more completely reduced?

Higher hydrogen proportion. Stores more energy in a smaller space.

40

What is key to energy release?

Electrons of chemical bonds that move and transfer. They start with more energy and end with less.

41

How do cells transfer energy from glucose to ATP?

By coupling of exothermic and endothermic. Glucose will lose hydrogen to become CO2 and oxygen will gain hydrogen to become H2O

42

In cellular respiration, what is oxidized and reduced?

Glucose is oxidized. Oxygen is reduced.

43

What step of cellular respiration is both anaerobic and aerobic?

Glycolysis

44

What is the equation for glycolysis?

1 glucose (6C) -> 2 Pyruvic Acid (3C)

45

What are the reactants of glycolysis?

Glucose, 2 ADP, 2 Phosphorus, 2 NAD+

46

What are the products of glycolysis?

2 pyretic acid, 2 ATP, 2 NADH

47

What is the net result of Krebs Cycle?

4 CO2, 2 ATP, 6 NADH, 2 FADH2

48

Electron Transport Chain results in how many ATP?

34 ATP

49

What substance allows for complete metabolism of glucose?

Oxygen

50

Fermentation

Anaerobic metabolism of glucose. No oxygen so no strong electron chain. Results in 2C or 3C and 2 ATP.

51

What is the evolution of energy transformation?

Chemosynthesis -> Fermentation -> Photosynthesis -> Cellular Respiration (only one to require oxygen)

52

What are the intermediates of cell respiration Krebs Cycle?

Acetyl CoA --> Citric Acid --> Alphaketosglutoric Acid --> Succinic Acid --> Malic Acid --> Oxaloacetic Acid