Unit 5 IB HL Biology

ATP

Adenosine Triphosphate, a modified nucleotide that serves as the universal energy currency of cells.

Nucleotides

Monomers for DNA and RNA.

Aerobic respiration

Process by which ATP is produced by the mitochondria.

Cellular energy

ATP is required in cells to transfer energy wherever it is needed.

Activ transport

Cellular process that requires ATP energy.

Anabolic reactions

Cellular processes that require ATP energy.

Muscle contractions

Cellular process that requires ATP energy.

Movement of cells or parts within cells

Cellular process that requires ATP energy.

Structure of ATP

Composed of adenine, ribose, and three phosphate groups.

ATP hydrolysis

Process of breaking the bond between the 2nd and 3rd phosphate groups in ATP.

ADP

Adenosine Diphosphate, a molecule formed after ATP hydrolysis.

Pi

Phosphate, a molecule released during ATP hydrolysis.

Endergonic reaction

Reaction that requires energy and stores it temporarily.

ADP phosphorylation

Process of converting ADP into ATP by adding a phosphate group and removing a water molecule.

Photosynthesis

Process by which light energy is converted into chemical energy (glucose and other organic molecules).

Autotrophs

Organisms that can produce their own chemical energy.

Photoautotrophs

Organisms that use light to produce their chemical energy through photosynthesis.

Trophic level

Position of an organism in the food chain.

Photolysis

Process of using light energy to split water molecules.

Chloroplast

Organelle responsible for photosynthesis in plant cells.

Thylakoids

Flattened, membrane-bound sacs in the chloroplast where light reactions occur.

Stroma

Fluid-filled space between the inner membrane of the chloroplast where the Calvin Cycle occurs.

Photosynthetic pigments

Molecules that absorb light and reflect certain colors.

Chlorophyll

Main photosynthetic pigment that reflects green light and absorbs other colors.

Absorption spectrum

Wavelengths of light absorbed by a pigment.

Paper chromatography

Lab technique to separate pigments based on their solubility.

Light reaction

First stage of photosynthesis that occurs in the thylakoids and produces ATP and NADPH.

Calvin Cycle

Second stage of photosynthesis that occurs in the stroma and converts CO2 into sugars using ATP and NADPH.

Reduction

Process of gaining electrons.

Oxidation

Process of losing electrons.

Photosystems

Integral protein complexes in the thylakoid membrane that contain chlorophyll and initiate the electron transport chain.

Reaction center

Protein complex within a photosystem where light energy is converted into chemical energy.

Photosystem 2

Photosystem sensitive to 680nm of light.

Photosystem 1

Photosystem sensitive to 700nm of light.

Photoactivation

Activation of chlorophyll and other pigments through the absorption of light energy.

Photolysis

Process of using light energy to break water molecules and replace missing electrons in photosystem 2.

Electron transport chain (ETC)

Series of integral protein complexes within the thylakoid membrane that transfer electrons and create a proton concentration gradient.

Proton concentration gradient

High concentration of protons (H+) in the thylakoid space.

Chemiosmosis

Diffusion of protons (H+) down their concentration gradient through ATP synthase, which synthesizes ATP.

ATP synthase

Transmembrane integral protein that synthesizes ATP using the energy from chemiosmosis.

Non-cyclic photophosphorylation

Process of ATP synthesis during the light reaction.

Cyclic photophosphorylation

Process where electrons from photosystem 1 are transferred back to the first electron transport chain, resulting in ATP synthesis.

Calvin Cycle

Light-independent reaction of photosynthesis that occurs in the stroma and converts CO2 into sugars using ATP and NADPH.

Carbon fixation

Process of attaching CO2 to a 5-carbon sugar called ribulose (RuBP).

Rubisco

Enzyme that catalyzes carbon fixation in the Calvin Cycle.

NADP+/NADPH

Electron carrier that is reduced to NADPH during the light reaction.

Photorespiration

Process where Rubisco mistakenly adds an O2 instead of a CO2, reducing the efficiency of the Calvin Cycle.

Rubisco

An enzyme that works best in high concentrations of CO2 to reduce the chance of an O2 being mistakenly added to RuBP.

Reduction

The phase of the Calvin cycle where each GP molecule is converted into a triose phosphate (TP) called Glyceraldehyde 3 phosphate (G3P).

Regeneration

The phase of the Calvin cycle where five triose phosphates (G3P) remain in the cycle and get rearranged into three RuBP molecules.

Triose Phosphate (G3P)

The molecule produced during the reduction phase of the Calvin cycle, which can be used to make glucose or other organic molecules.

Limiting Factors of Photosynthesis

Factors that limit the rate of photosynthesis, including light intensity, CO2 concentration, temperature, and the wavelength of light.

Cellular Respiration

The process by which living organisms extract energy from organic molecules to produce ATP.

Aerobic Respiration

The process of breaking down organic molecules using O2 to produce ATP.

Anaerobic Respiration

The process of breaking down organic molecules without using O2 to produce ATP.

Mitochondrial Structure

The structure of mitochondria, including the double membrane, inner membrane with highly folded cristae, outer membrane, intermembrane space, and mitochondrial matrix.

Glycolysis

The process of breaking glucose into two pyruvate molecules, occurring in the cytoplasm of cells.

Link Reaction

The process that occurs in the mitochondrial matrix, converting pyruvate into Acetyl-CoA and producing CO2 and NADH.

Krebs Cycle

A cyclical metabolic pathway in the mitochondrial matrix that finishes the breakdown of glucose, producing NADH, FADH2, CO2, and ATP.

Oxidative Phosphorylation (OxPhos)

The process of ATP production during cellular respiration, utilizing an electron transport chain and ATP synthase.

Fermentation

The process of generating ATP without O2, either through alcohol fermentation or lactic acid fermentation.

Alcohol Fermentation

A type of fermentation where pyruvate is converted into ethanol and CO2, regenerating NAD+.

Lactic Acid Fermentation

A type of fermentation where pyruvate is converted into lactate, regenerating NAD+.

ATP Synthase

An enzyme that performs ADP phosphorylation to create ATP during chemiosmosis in OxPhos.

Chemiosmosis

The diffusion of H+ down its concentration gradient through ATP synthase, providing the energy needed to phosphorylate ADP into ATP.

Electron Transport Chain

A series of protein complexes embedded in the inner mitochondrial membrane that transfers electrons and pumps H+ into the intermembrane space during OxPhos.

Mitochondrial Proton Gradient

The high concentration of H+ in the intermembrane space and low concentration in the mitochondrial matrix, created by the ETC during OxPhos.

Anaerobic Respiration

Produces ATP in the absence of O2

Anaerobic Respiration

Faster than aerobic respiration

Anaerobic Respiration

Doesn't require special structures (ETC/ATP synthase)

Anaerobic Respiration

Much fewer ATP produced compared to aerobic respiration

Aerobic Respiration

Much more ATP is produced

Aerobic Respiration

Requires O2

Aerobic Respiration

Requires special structures (ETC/ATP synthase)

Aerobic Respiration

Slower than anaerobic respiration

ATP

Role of ATP in plants

ATP

How is ATP produced in plants?

ATP

Cellular processes in plants that require ATP

ATP

Can plants store ATP for later use?

ATP

How is ATP used in photosynthesis?

ATP

Fate of ATP during cellular respiration in plants

ATP

Specific enzymes involved in ATP synthesis in plants

ATP

Contribution of ATP to plant growth and development

ATP

Can plants obtain ATP from sources other than cellular respiration?

ATP

Factors affecting ATP production in plants

ATP to ADP

Process of converting ATP to ADP

ATP to ADP

Enzyme responsible for the conversion of ATP to ADP

ATP to ADP

Relationship between the conversion of ATP to ADP and energy release

ADP to ATP

Possibility of converting ADP back to ATP in plants

ADP

Role of ADP in cellular metabolism

ADP

Specific cellular processes that require ADP

ADP

Impact of the conversion of ATP to ADP on plant growth and development

ADP

Can plants obtain ADP from external sources?

ADP to ATP

Factors affecting the conversion of ATP to ADP in plants

ATP to ADP ratio

Impact on cellular energy levels in plants