C1.2 HL only

Question 1

mitochondria

Answer 1

membrane-bound cell organelles often referred to as the “powerhouses” of the cellbecause they are responsible for generating most of the cell’s supply of adenosine triphosphate (ATP), a molecule that stores chemical energy

Question 2

matrix

Answer 2

the space within the inner membrane of a mitochondrion, a key organelle in eukaryotic cells.It’s a gel-like substance, often described as a viscous aqueous solution, that houses various crucial components for cellular respiration and ATP (energy) production

Question 3

outer mitochondrial membrane

Answer 3

the outermost lipid bilayer that surrounds the entire mitochondrion, separating it from the cytoplasm of the cell.It’s a semi-permeable barrier, meaning it allows some molecules to pass through while restricting others

Question 4

inner mitochondrial membrane

Answer 4

a highly specialized membrane within mitochondria that separates the mitochondrial matrix from the intermembrane space.It plays a critical role in cellular energy production by housing the electron transport chain and ATP synthase, essential for oxidative phosphorylation and ATP synthesis

Question 5

inter-membrane space

Answer 5

the region located between the inner and outer membranes of mitochondria (or chloroplasts).It’s a crucial compartment for various cellular processes, most notably cellular respiration, where it plays a key role in ATP production

Question 6

cristae

Answer 6

folds in the inner membrane of mitochondria, the organelles responsible for energy production in eukaryotic cells.These folds significantly increase the surface area of the inner mitochondrial membrane, allowing for a greater number of protein complexes involved in cellular respiration to be embedded within it

Question 7

hydrogen carrier

Answer 7

a molecule that accepts and transfers hydrogen atoms (or, more precisely, electrons and protons) during metabolic processes, particularly in cellular respiration and photosynthesis

Question 8

NAD (Nicotinamide Adenine Dinucleotide)

Answer 8

a vital coenzyme found in all living cells, acting as a crucial player in various metabolic processes. It exists in two forms, oxidized (NAD+) and reduced (NADH), and facilitates redox reactions by shuttling electrons between molecules

Question 9

NADH (reduced NAD)

Answer 9

a crucial coenzyme that plays a vital role in cellular metabolism, specifically in redox (reduction-oxidation) reactions

Question 10

FAD (Flavin Adenine Dinucleotide)

Answer 10

a vital redox-active coenzyme, meaning it facilitates electron transfer in various biochemical reactions

Question 11

FADH2 (reduced FAD)

Answer 11

the reduced form of FAD (flavin adenine dinucleotide).FAD is a redox cofactor, meaning it can accept and donate electrons in biochemical reactions

Question 12

coenzymes

Answer 12

non-protein organic molecules that assist enzymes in catalyzing biochemical reactions

Question 13

Glycolysis

Answer 13

a metabolic pathway that extracts energy from glucose by breaking it down into pyruvate

Question 14

pyruvate

Answer 14

a key molecule in cellular metabolism, specifically as the output of glycolysis and a precursor for various biochemical pathways.It’s a three-carbon molecule formed when glucose is broken down

Question 15

lysis

Answer 15

the breaking down of a cell or organic molecule

Question 16

phosphorylation

Answer 16

a crucial chemical process where a phosphate group is added to an organic molecule, like a protein or a sugar

Question 17

triose phosphates (TP)

Answer 17

a metabolite that occurs as an intermediate in several central pathways of all organisms

Question 18

ethanol

Answer 18

ethyl alcohol or grain alcohol, is a simple alcohol (C2H6O) naturally produced through the fermentation of sugars by yeasts

Question 19

carbonic acid

Answer 19

a weak acid formed when carbon dioxide dissolves in water

Question 20

link reaction

Answer 20

a crucial step in cellular respiration that connects glycolysis to the Krebs cycle.It occurs in the mitochondrial matrix and involves the conversion of pyruvate, a product of glycolysis, into acetyl-CoA

Question 21

Decarboxylation

Answer 21

a chemical reaction that removes a carboxyl group (COOH) from a molecule, releasing carbon dioxide (CO2)

Question 22

carboxyl group

Answer 22

a functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (OH), with the formula -COOH

Question 23

Coenzyme A

Answer 23

a vital molecule in cellular metabolism, acting as a carrier for acyl groups (like acetyl groups) and participating in various metabolic pathways

Question 24

acetyl group

Answer 24

a small molecule consisting of two carbon atoms, three hydrogen atoms, and one oxygen atom

Question 25

Krebs cycle

Answer 25

a series of chemical reactions that extract energy from molecules like acetyl-CoA, derived from carbohydrates, fats, and proteins

Question 26

oxaloacetate (4C)

Answer 26

a series of enzyme-controlled reactions. During the Krebs cycle: acetyl coenzyme A releases a two-carbon molecule, which reacts with a four-carbon molecule to produce a six-carbon molecule. 4C molecule = oxaloacetate

Question 27

citrate (6C)

Answer 27

Acetate (2C) combines with oxaloacetate (4C), forming a 6C molecule called citrate. Citrate is decarboxylated and dehydrogenated. Citrate (6C) loses a carboxyl group and forms a 5C molecule, releasing CO2 in the process

Question 28

Electron transport chain (ETC)

Answer 28

a series of protein complexes and molecules embedded in the inner mitochondrial membrane (or the cell membrane in prokaryotes) that facilitate the transfer of electrons from electron donors to electron acceptors through redox reactions

Question 29

final electron acceptor

Answer 29

the last molecule in an electron transport chain to receive electrons.This molecule plays a crucial role in energy production within cells, particularly during cellular respiration and photosynthesis

Question 30

chemiosmosis

Answer 30

a biological process that couples the movement of ions across a membrane to the synthesis of ATP, the cell's primary energy currency

Question 31

ATP synthase

Answer 31

a crucial enzyme that acts as a molecular machine, synthesizing ATP (adenosine triphosphate) by harnessing the energy from a proton gradient across a membrane

Question 32

triglycerides

Answer 32

a type of lipid (fat) composed of a glycerol molecule bonded to three fatty acid molecules

Question 33

fatty acid chains

Answer 33

long hydrocarbon chains (a chain of carbon and hydrogen atoms) with a carboxyl group (-COOH) at one end.