Unit 2 - Metabolic Processes

Question 1

Metabolism

Answer 1

the sum of all chemical reactions that occur in the cell

Question 2

Metabolic Pathway

Answer 2

a sequential series of chemical reactions in living cells; each reaction is catalyzed by an enzyme

Question 3

Catabolism

Answer 3

process of breaking down compounds into smaller molecules to RELEASE energy

Question 4

Anabolism

Answer 4

process of USING energy to build large molecules from smaller molecules

Question 5

Endergonic

Answer 5

Chemical rxn that REQUIRES energy, energy has to go in, products have more energy than reactants

Question 6

Exergonic

Answer 6

Chemical rxn that RELEASES energy, energy has to leave, products have less energy than reactants

Question 7

Aerobic Cellular Respiration (definition, goal, NAME the stages)

Answer 7

C.R. includes the catabolic pathways that break down energy-rich compounds to produce ATP, requires oxygen, exergonic process, releases energy.

Goals: break glucose to get energy released in the form of ATP

Stages: Glycolysis, Pyruvate Oxidation, Krebs Cycle, Oxidative Phosphorylation

Question 8

Substrate Level Phosphorylation (definition, what stages it occurs in)

Answer 8

Energy from the rxn of the substrate drives phosphorylation -> phosphate group is transferred to ADP to make ATP.
Occurs in Glycolysis and Krebs Cycle

Question 9

Glycolysis (location, energy yield, starting molecule and ending molecule)

Answer 9

of rxns: 10

Location: Cytosol (in cytoplasm)
Anaerobic (does not require oxygen)
Net Energy: 2ATP, 2NADH
Start: glucose. End: 2 pyruvate

Question 10

Pyruvate Oxidation (location, energy yield, starting and ending molecule)

Answer 10

Location: mitochondrial matrix
Requires oxygen
Net energy: 2NADH
Start: 2 pyruvate. End: 2 acetyl-coA, 2 CO2

Question 11

Krebs Cycle (location, energy yield, input molecule)

Answer 11

Location: mitochondrial matrix
Requires oxygen
Net Energy: 2ATP, 6NADH, 2FADH
4CO2 also produced
Input: 2 acetyl-CoA

Question 12

Oxidative Phosphorylation (location, purpose, energy yield, processes/structures involved)

Answer 12

Location: inner mitochondrial membrane
Requires oxygen
Couples the oxidation of electron carriers by the electron transport chain with the synthesis of ATP.
Net Energy: theoretically 36-38ATP
Structure: Electron Transport Chain
Process: Chemiosmosis

Question 13

Electron Transport Chain (definition, function, structure)

Answer 13

Series of electron carriers and protein complexes, arranged in order of increasing electronegativity, embedded in inner mitochondrial membrane that accept and donate electrons in a series of rxns.

Proteins 1, 3, 5 are H+ pumps. Proteins 2, 4 are mobile electron carriers

-ETC is highly exergonic, free energy lost at each step is used to pump H+ out of matrix creating H+ ion gradient
-Oxygen is final electron acceptor, water is produced when O accepts the electrons and reacts with H+ ions. -The NADH made in glycolysis needs the GLYCEROL-PHOSPHATE SHUTTLE to move into the inner membrane and it changes to FADH2.

Question 14

Chemiosmosis (explain process)

Answer 14

-energy from reduced electron carriers used to establish electrochemical gradient (Proton Motive Force)
-inner mitochondrial membrane is impermeable to H+ ions, so a high concentration of H+ ions builds up
-when H+ ions move along their gradient, through an ATP synthase complex, energy is released
-this energy is used to phosphorylate ADP into ATP
-ATP can then leave the membrane by facilitated diffusion into cytoplasm where it can drive endergonic processes

Question 15

Anaerobic Respiration (definition)

Answer 15

When oxygen is not used as final electron acceptor, rather NO2, SO4, CO2, or Fe(III) is used.
Obligate anaerobes: die in presence of oxygen
Facultative anaerobes: tolerate oxygen or non-oxygen environment

Question 16

Fermentation (definition, types)

Answer 16

Cells have limited supply of NAD+ so if no oxygen available:
organisms can recycle NAD+ by transferring H+ atoms of NADH to organ molecules.
Fermentation is less efficient at supplying energy since only the ATP generated in glycolysis is produced (2ATP).
Two common types: Lactate and Ethanol

Question 17

Lactate Fermentation (process, function)

Answer 17

Some animal muscle cells function temporarily without oxygen
after glycolysis: pyruvate and NADH undergo REDOX rxn, NADH is oxidized, regenerating NAD+ for glycolysis. Pyruvate is reduced, becoming lactate/lactic acid.
Oxygen is ultimately needed to allow the lactate to be metabolized.

Question 18

Alcohol Fermentation in Yeast (process, function)

Answer 18

Yeast and some bacteria are facultative anaerobes when there is no oxygen available, they convert pyruvate to ethanol and CO2.
CO2 leaves pyruvate which becomes acetaldehyde.
Acetaldehyde is reduced becoming ethanol, NADH is oxidized regenerating NAD+.
Used to manufacture baked goods, alcoholic drinks, and biofuels

Question 19

Photosynthesis (definition, two main sets of rxns)

Answer 19

Uses/captures light energy and uses it to produce a carbohydrate (ie glucose). Enables plants to produce structural and metabolic substances that aid in their survival.
Two Main Sets of RXNS: light-DEPENDENT rxns, light-INDEPENDENT rxns

Question 20

Thylakoid (structure, function)

Answer 20

A membrane system within a chloroplast forms interconnected disks that look like flattened pancakes.
Thylakoids absorb energy from the sun.

Question 21

Pigment (function, location, main types)

Answer 21

Compounds that absorb certain wavelengths of visible light while reflecting others. In a leaf, photosynthetic pigments trap light energy and pass it along to other compounds like hot potato, pigments are embedded in thylakoid membrane.
Leafs look green bc chlorophyll molecules reflect green and yellow and absorb others.
More variety of pigments, more photosynthesis

Chlorophyll a - only pigment that can transfer the energy of light to the carbon fixation rxns of photosynthesis, passes energy to primary electron acceptor
Chlorophyll b- accessory pigment, absorbing photons that chlorophyll a absorbs poorly or not at all

Question 22

Photosystems (structure, function, antenna complex)

Answer 22

protein-based complexes composed of clusters of pigments that absorb light energy. When a pigment absorbs a photon it passes the energy to chlorophyll a in form of excited electron.
combination of pigments and chlorophyll a is called the reaction center.
Antenna complex: accessory pigments gather energy from light so that the energy can be directed to rxn center.

Question 23

Light Dependent Reactions (purpose, summarize three parts)

Answer 23

Purpose: make ATP and NADPH to fuel the Calvin Cycle
3 Parts:
1. Photoexcitation: absorption of photon by an e- of chlorophyll
2. Electron Transport: transport excited e- through e- carriers, causes H+ pumping through photosynthetic membrane creation of electrochemical gradient and eventual e- acceptor reduction
3. Chemiosmosis: ATP synthase complex causes PHOTOPHOSPHORYLATION (adp to atp)

(more indepth explanations in notes, too much for flash cards)

Question 24

Light Independent Reactions

Answer 24

Calvin Cycle. Fix CO2 from inorganic to organic. Occurs in stroma. Can occur in presence or absence of light.

Three Phases:
1. Carbon Fixation: converts inorganic CO2 to organic Carbon, requires enzyme Rubisco, RuBP combines with CO2
2. Reduction Reactions: adding energy, activated by ATP, reduced by NADPH producing G3P, some regenerate RuBP, some exit to make glucose
3. Regeneration of RuBP: energy supplied by ATP to break and reform bonds to produce more RuBP.

6 times for 1 glucose