Honors Biology- Unit 5, Concept 1 (Photosynthesis), and Concept 2 (Cellular Respiration)

Palisade Mesophyll

A tightly packed group of cells found under the epidermis of leaves that contain chloroplasts, which are used to absorb light for photosynthesis.

Spongy Mesophyll

A tissue found in the lower layer of leaves that has many spaces for gas exchange to take place. It allows CO₂ to easily diffuse in, while O₂ (oxygen) diffuses out.

Xylem

A tube-like tissue that carries water upward from the roots to every part of a plant.

Aeorbic Respiration

A type of respiration that requires oxygen and completes all 3 steps of CS: Glycolysis- Krebs (Citric Acid) Cycle- Electron Transport Chain. Produces about 36 ATP.

Epidermis (plant)

Cells that cover and protect the surface of the leaf and secrete the waxy cuticle. It is also thin so light can penetrate it and reach the palisade mesophyll.

Granum

A stacks of pigment-containing thylakoids in a plant's chloroplasts.

Photosynthesis Equation

6CO₂ + 6H₂O + light energy (Reactants) --> C₆H₁₂O₆ + 6O₂ (Products)

Cellular Respiration

A 3-step exothermic process used many organisms including animals, plants, fungi, algae, and some protists, to convert the chemical energy in glucose to stored ATP energy. It begins with Glycolysis, then enters the Krebs Cycle, and finishes with the Electric Transport Chain, creating around 36-38 ATP in total.

C₆H₁₂O₆ (Glucose)

A carbohydrate molecule with 6 carbon, 12 hydrogen, and 6 oxygen atoms. -Reactant of cellular respiration. -Product of photosynthesis.

Chloroplast

A cell organelle only found in plants whose primary function is facilitating photosynthesis by absorbing sunlight to be used to create stored chemical energy in the form of glucose.

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy through photosynthesis. Where light-dependant reactions take place.

Inner-membrane (Mitochondria)

A folded internal membrane in the mitochondria where the Electron Transport Chain (3rd step) of CS occurs. C/B in the picture

Anaerobic Respiration

A form of respiration that doesn't require oxygen. Instead of completing all 3 steps of CS, fermentation will occur after Glycolysis, producing only 2 ATP.

Cytoplasm

A jellylike fluid inside the cell in which the organelles are kept and Glycolysis (1st step) of CS.

Stomata

A microscopic pore (opening) surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant.

CO₂ (Carbon Dioxide)

A molecule with 1 carbon atom and 2 oxygen atoms. -Reactant of photosynthesis. -Product of cellular respiration.

H₂O (Water)

A molecule with 2 hydrogen atoms and 1 oxygen atom. -Reactant of photosynthesis. -Product of cellular respiration.

O₂ (Dioxygen-Breathable Oxygen)

A molecule with two oxygen atoms. -Reactant of cellular respiration. -Product of photosynthesis.

Roots

A part of a plant that anchors it to the ground, but more importantly absorbs the photosynthetic reactant H₂O (water). Cells of this do not have stomata.

Chlorophyll a

A photosynthetic pigment that participates directly in the light reactions, which convert solar energy to chemical energy.

Chlorophyll

A pigment in plants that absorbs light energy to energize electrons that are used to carry out photosynthesis, and gives plants their characteristic green color. It does this by absorbing every other color of light besides green, which it reflects.

Photorespiration

A process in photosynthesizing organisms that consumes (increases) oxygen, releases (decreases) carbon dioxide, generates no ATP, and decreases photosynthetic output (sugars); generally occurs on hot, dry, bright days, when stomata close to prevent water loss, and the oxygen concentration in the leaf exceeds that of carbon dioxide.

Light-Independent (Calvin-Cycle) Reactions Function (PS)

A process in the stroma of chloroplasts that serves as the "synthesis" (creation) part of photosynthesis, as it uses the energy-carrying molecules ATP and NADPH (from the light-dependant reactions) to make sugar (glucose).

Light-Dependant Reactions Function (PS)

A process in the thylakoid membrane of chloroplasts that serves as the "photo" (light) part of photosynthesis, as it captures the solar light energy and stores it in the energy-carrying molecules ATP and NADPH.

Endothermic Energy

A process in which energy is absorbed/stored.

Exothermic Energy

A process in which energy is released.

Cartenoids

Absorb wavelengths of light different from those absorbed by chlorophyll, but still contribute to photosynthetic processes.

Acetyl CoA

Acetyl coenzyme A; the entry molecule for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme.

Chlorophyll b

An accessory photosynthetic pigment that transfers energy to chlorophyll a.

Photosynthesis

An endothermic energy-making process in the chloroplasts used by plants, some types ofr bacteria, and algae to utilize sunlight to convert CO₂ (Carbon dioxide) and H₂0 (Water) into C₆H₁₂O₆ (Glucose), a carbohydrate/sugar that is used as stored energy, and O₂ (Oxygen). It is split into two parts, light-dependant reactions and light-independent reactions (Calvin cycle).

Mitochondria

An organelle found in large numbers in most cells, in which most of the parts of cellular respiration occur.

Coenzymes

An organic molecule that is a necessary participant in some enzymatic reactions; helps catalysis by donating or accepting electrons; e.g., a vitamin, ATP, NAD+, FADH.

Autotroph

An organism that makes its own food, namely plants, which use photosynthesis.

Heterotrophs

An organism that obtains organic food molecules by eating other organisms or their by-products.

Cellular Respiration Equation

C₆H₁₂O₆ + 6O₂ (Reactants) --> 6CO₂ + 6H₂O (Products)

Photosynthesis Origin

First found in unicellular, prokaryotic organisms, the biological process eventually evolved in eukaryotic cells, particularly plants and algae.

Waxy Cuticle

Forms a waterproof layer to stop water loss due to photosynthesis in leaves.

Leaf Guard Cells

Groups of two cells that flank either side of the stomatal pore and regulate the opening and closing of the pore. This helps to regulate water loss, which happens when water in the leaves evaporates and diffuses out.

Lactic Acid Fermentation

Lactic acid is produced as a reactant in muscle cells from the reduction of pyruvate (under anaerobic conditions) to regenerate NAD+ so that glycolysis can continue. A rise in lactic acid usually accompanies an increase in physical activity and causes a burning sensation.

Phloem Vessel

Long continuous tubes composed of living phloem cells that transport sugars (glucose) from a plant's leaves to various parts of the plant.

CAM

One of the alternative pathways used by plants, specifically cacti and pineapples, to prevent photorespiration. This causes the stomata to open at night to conserve water, rather than during the day. Though it serves as a method to sustain photosynthesis, it also results in slower growth of the plant.

C4

One of the alternative pathways used by plants, specifically corn and sugar cane, to avoid photorespiration. The stomata closes partially during the hottest parts of the day, not completely. This also causes the plants to need 1/2 as much water than normal ones.

Amount of CO₂

One of the factors affecting photosynthesis. When there is more of this, there are more materials to work with and process during photosynthesis, which can allow it to run more efficiently. The opposite can happen when there is less.

Temperature

One of the factors affecting photosynthesis. When this is higher, kinetic energy transfer causes molecules to move faster, which may speed up photosynthesis. The opposite happens when it is lower.

Light Intensity

One of the factors affecting photosynthesis. When this is higher, more energy-causing light reactions occur, benefiting photosynthesis. The opposite happens when it is lower.

Light Independent Reactions (Calvin Cycle) Process (PS)

Powered by ATP and NADPH from the light-dependant reactions, enzyme-assisted reactions produce 3-carbon sugars (C₃H₆O₃) from the CO₂ (Diffused in via the stomata) and H+ released by the broken water molecules. This cycle happens twice, and the 3-carbon sugars combine to form C₆H₁₂O₆ (glucose).

Krebs (Citric Acid) Cycle Products & Reactants

Reactant(s): Coenzymes (Acetyl CoA) Product(s): 2 ATP, Carbon Dioxide, & FADH2 and NADH (Electron carrier coenzymes)

Glycosis Products & Reactants

Reactant(s): Glucose Product(s): 2 ATP, 2 Pyruvates & Coenzymes (2 NADH)

ETC Products & Reactants

Reactant(s): Oxygen & Coenzymes Product(s): Water & ATP

Vacuole Photosynthesis Use

Stores glucose for long term uses, like growth of tissue.

Light-Independent Reaction/Calvin Cycle (PS) and Krebs-Cycle/Glycolysis (CR) Relationship

The CR part gets rid of CO2 as a waste product, while the PS part takes it in as a reactant. The PS part also makes C6H1206 (glucose) as a waste product, while the CR part takes it as a reactant. Both are cyclic processes.

Light-Dependant Reaction (PS) and Electron Transport Chain (CR) Relationship

The CR part gets rid of H2O as a waste product, while the PS part takes it in as a reactant. The PS part also makes O2 as a waste product, while the CR part takes it as a reactant. Both involve an electron transport chain.

Alcoholic Fermentation

The anaerobic process by which yeasts and other microorganisms break down sugars to form carbon dioxide and ethanol

Fermentation (Anaerobic Respiration)

The breakdown of sugars without the use of oxygen, regenerates NAD+ so glycolysis can continue. Comes after glycolysis.

Chloroplast Membrane

The double membrane that regulates the movement of molecules in and out of this organelle; plus membrane-bound sacs in the interior.

Oxidative Phosphorylation (Electron Transport Chain)

The electron transport chain. A process occurring in the mitochondria that results in the formation of ATP from the flow of electrons across the inner membrane to bind with oxygen.

Glycolysis

The first step of CS; happens in the cytoplasm. A 6-carbon molecule is broken down into 2 pyruvate molecules (each with 3 carbons). 2 ATP Molecules are produced from this, and electrons are passed on to NAD+ (Making them NADH), which then go to the Electron Transport Chain. It requires no oxygen, so it is considered anaerobic.

Stroma

The fluid of the chloroplast surrounding the thylakoid membrane; is involved in the synthesis of organic molecules from carbon dioxide and water. Where light-independent (Calvin cycle) reactions take place.

Matrix (Mitochondria)

The fluid-filled inner compartment of the mitochondria; is where the Krebs Cycle (Citric Acid) (2nd step) of CS occurs. D in the picture.

Leaf

The main photosynthetic organs of plants; have a large surface area to absorb more sunlight and have tiny pores called stomata that allow for gas exchange (of Carbon Dioxide and Oxygen), as well veins made from xylem and phloem tissues to transport photosynthetic products (Water and Glucose).

Chemiosmosis

The second part of the ETC (CR). A process for synthesizing ATP using the energy of an electrochemical gradient and passing of H+ through the ATP synthase enzyme. This gives energy for the combination of ADP and an inorganic phosphate to make ATP.

Krebs Cycle (Citric Acid Cycle)

The second step of CS (when oxygen is available); happens in the matrix, and uses Acetyl CoA in oxidation-reduction (redox) reactions. Citric acid breaks down the pyruvate molecules (pyruvic acid) that have just entered the mitochondria, releasing CO₂, ATP, and high-energy electrons. These electrons travel to the ETC on FADH and NAD+ (now made into FADH₂ and NADH after adding electrons). This is an aerobic process and makes 2 ATP.

Electron Transport Chain (CS)

The third and final step of CS; happens in the inner mitochondrial membrane. The high-energy electrons travel along a series of molecules on the coenzymes NADH and FADH2, which move their H+ through protein pumps. Some join with the proton H+ and O₂ to become H₂O, which is released from the cell. The rest of these electrons transport H+ ions across the mitochondria's membrane, through ATP Synthase, an enzyme that makes ATP from ADP and an inorganic phosphate. This is an aerobic process that makes about 34 ATP.

Transition Reaction (Between Glycolysis and Krebs)

This takes place between glycolysis and the Krebs cycle. Pyruvate is pumped into the mitochondrial matrix using active transport. It gets oxidized to form Acetyl coenzyme A - also called Acetyl-CoA. Two more NADH coenzymes and carbon dioxide are released.

Stroma Lamella

Tubular membranes that connect the grana in the chloroplast.

Light-Dependant Reactions Process (PS)

Using solar energy, H₂O (water) is split up into hydrogen, oxygen, and electrons. From this, O₂ oxygen is released from the plants as a waste product. ATP and NADPH are also created and charged due to this light energy after passing through the electron transport chain. These are then sent to the stroma for the light-independent reaction (Calvin Cycle).

H+

hydrogen ion (proton).