Unit 3- Photosynthesis and Cellular Respiration

autotrophic

Organisms that make their own food

Photoautotrophs

obtain and use light energy (photons) to make food

prokaryotes

Cells that do not contain nuclei

Cyanobacteria

Bacteria that can carry out photosynthesis

chemoautotroph

organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions

chloroplast

Site of photosynthesis in a cell

chlorophylls

pigments required for photosynthesis

mesophyll

Spongy tissue in the interior of the leaf where most chloroplasts are found.

stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move

stroma

- fluid portion of the chloroplast; outside of the thylakoid

- site of Calvin cycle

grana

stacks of thylakoids

Thylakoid

saclike photosynthetic membranes found in chloroplasts, where chlorophyll is found

outer membrane

part of chloroplast, permeable to small organic molecules

intermembrane space

narrow area between inner and outer membranes in the chloroplast

chlorophyll a

pigment directly involved in photon capture

antenna pigments

shuttle energy to chlorophyll a

types of antenna pigments

chlorophyll b, carotenoids, xanthophyll, phycobilins

absorption spectrum

A graph showing wavelengths absorbed by photosynthetic pigments

action spectrum

A graph that shows the rate of photosynthesis at different wavelengths of light

principle pigment

chlorophyll a- the most useful pigment in plants

Source of electrons in photosynthesis

double bonds, responsible for the ability to absorb light energy from photons

Photosynthetic reaction

6CO2 + 6H2O ----> C6H12O6 + 6O2

light dependent reaction

set of reactions in photosynthesis that use energy from light to produce ATP and NADPH. occurs in thylakoid membrane

Adenosine Triphosphate (ATP)

compound used by cells to store energy

oxidation

loss of electrons

reduction

gain of electrons

membrane structures in the thylakoid

an "assembly line" for light dependent reactions, enzymes and proteins

atp synthase

Large protein that uses energy from H+ ions to produce ATP

photosystems

light harvesting complexes consisting of proteins and pigments in thylakoid membranes, contains reaction centres

reaction centres

special pair of chlorophyll molecules found at the core of each photosystem

photosystem I

One of two light-harvesting units of a thylakoid membrane; it uses the P700 reaction-center chlorophyll. Produces NADPH

Photosystem II

One of two light-harvesting units of a thylakoid membrane; it uses the P680 reaction-center chlorophyll. Produces ATP

photon

a particle of light

electron transport chain

series of electron carrier proteins that shuttle high-energy electrons in a series of redox reactions

Photophosphorylation

ATP is formed utilizing the energy of sunlight

non-cyclic photophosphorylation

the synthesis of ATP and reduced NADP involving photosystems I and II.

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

ADP + Pi

During chemiosmosis, ATP will be made from this

NADPH

electron carrier that provides high-energy electrons for photosynthesis- "reducing power"

cyclic photophosphorylation

breaks usual pattern and repeats cycle through PSI, only produces ATP

Light Independent Reactions (Calvin Cycle)

set of reactions in photosynthesis in the stroma, energy from ATP and NADPH is used to make glucose

Thylakoid lumen

A fluid-filled interior space enclosed by a membrane

Carbon fixation

The initial incorporation of carbon from CO2 into an organic compound

Intermediates

Unstable/short-lived

RuBisCo

enzyme that converts inorganic carbon dioxide molecules into organic molecules in the Calvin cycle

G3P (PGAL)

final product of the Calvin cycle

3PGA

Helps to make G3P with ATP and NADPH, produced after carbon fixation

Steps of the Calvin cycle

carbon fixation, reduction, regeneration

Reduction

- Second part of the Calvin Cycle

- NADPH and ATP dispense electrons => NADP+ & ADP+P

- G3P formed

Regeneration

Step 3 of the Calvin Cycle: The remaining G3P is used in reactions that use ATP to regenerate RuBP

C3 plants

Organisms that Produce 3c intermediates in the Calvin cycle

final electron acceptor (photosynthesis)

the last chemical entity, NADP+, in the light dependent cycle that accepts electrons transferred to it, an oxidizing agent

Cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

aerobic respiration

Respiration that requires oxygen

anaerobic respiration

Non primary form of Respiration that does not require oxygen

Krebs Cycle (Citric Acid Cycle)

aerobic respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

oxidative phosphorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration

Alcoholic fermentation

The process by which yeast and plants turn sugar into carbon dioxide (CO2) and alcohol without oxygen

lactic acid fermentation

A series of anaerobic chemical reactions using that supplies energy when oxygen is scarce in animals- Lactic acid & CO2

Mitochondria

organelle that is the site of ATP (energy) production

inner membrane of mitochondria

houses components for cellular respiration

Cristae

folds of the inner membrane of a mitochondrion

Glycolysis

the breakdown of glucose by enzymes, releasing energy, takes place in the cytoplasm

Metabolism

the chemical processes that occur within a living organism in order to maintain life.

Catabolism

Metabolic pathways that break down molecules, releasing energy.

Anabolism

Metabolic pathways that construct molecules, requiring energy. Unstable

coupling reactions

The pairing of reactions of which one releases enough energy for the other to occur

second law of thermodynamics

Energy cannot be changed from one form to another without a loss of usable energy

Coenzyme

an organic cofactor required for enzyme activity

FAD coenzyme

flavin adenine dinucleotide, a coenzyme in cellular respiration

Essential coenzymes in cellular respiration

FAD and NAD+

NAD+ coenzyme

Electrons from organic compounds are usually first transferred to this, coenzyme in cellular respiration

Enzyme

protein that acts as a biological catalyst

NADH

the reduced form of NAD+; an electron-carrying molecule that functions in cellular respiration

Metabolites

molecules made or broken down in the body

electron transport chain in cellular respiration

The last reactions of cellular respiration, in which electrons are passed from NAD or FAD, through a series of carriers, to

oxygen, with the production of ATP

phosphorylation

the addition of a phosphate group to a molecule (ADP + Pi = ATP)

Pyruvate

Organic compound with a backbone of three carbon atoms. Two molecules form as end products of glycolysis

Acetyl- CoA

the entry compound for the citric acid cycle in cellular respiration, formed from a pyruvate attached to a coenzyme

Energy investment step

step 1 of glycolysis: Two ATP are used to activate glucose

Glucose splits into two G3P molecules

Energy harvesting step

Electrons and hydrogen ions are removed from the G3P producing two NADH and net ATP of 2. Cellular respiration

Substrate

A specific reactant acted upon by an enzyme

substrate-level phosphorylation

The formation of ATP by directly transferring a phosphate group to ADP from a substrate in catabolism.

mitochondrial matrix

the space inside the inner membrane of a mitochondrion

Products of the krebs cycle

6 NADH, 2 FADH2, 4 CO2, 2 ATP

Final electron acceptor (cellular respiration)

Oxygen accepts electrons and hydrogen protons to form water

Lactic acid

product of fermentation in animal cells, produced from Pyruvate during glycolysis

dephosphorylation

removal of a phosphate group from a molecule, ATP used

Hydrolyctic Enzymes

enzymes that use water to break bonds

Resonance structure

a structure that occurs when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion

active transport

Energy-requiring process that moves material across a cell membrane against a concentration gradient [low]=> [high]

Passive transport

Requires NO energy, [high]=> [low] concentration, Moves with the concentration gradient

cytoplasmic streaming

A circular flow of cytoplasm, that speeds the distribution of materials within cells

Cell division

Process by which a cell divides into two new daughter cells

Cytokinesis

Division of the cytoplasm during cell division

Endocytosis

process by which a cell takes material into the cell

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

receptor-mediated endocytosis

The uptake of specific molecules based on a cell's receptor proteins

Exocytosis

release of substances out a cell by the fusion of a vesicle with the membrane.