Cellular Energy: ATP, Photosynthesis, Cellular Respiration, and Fermentation

Vocabulary flashcards covering cellular energy, ATP structure and function, stages and structures of photosynthesis, stages of cellular respiration, and types of fermentation.

Energy

The ability to do work.

Chemical Energy

Energy stored in the bonds of chemical compounds; allows energy to be transported around the cell.

ATP

Adenosine triphosphate; the cell's energy currency that stores and transports energy from one location to another.

ADP

Adenosine diphosphate; the product formed alongside an independent phosphate ($P_i$) when the bond between the 2nd and 3rd phosphate groups of ATP is broken.

Autotrophs

Organisms that make their own food from sunlight through photosynthesis.

Heterotrophs

Organisms that must consume other organisms for food.

Chlorophyll

Pigment found in chloroplasts that absorbs light energy (blue/violet and red) and reflects green and yellow.

Chloroplast

Organelle with $2$ membranes where photosynthesis occurs.

Thylakoids

Stacks of sac-like membranes inside the chloroplast where light-dependent reactions take place.

Stroma

The space surrounding the thylakoid stacks in a chloroplast where light-independent reactions take place.

Pigments

Molecules that absorb some colors of light energy and reflect others.

$$NADP^+$$

Transport molecule that carries high-energy electrons from the light-dependent to the light-independent reactions.

Photosystems

Combinations of chlorophyll pigments and specialized proteins that collect light to energize electrons.

Electron Transport Chain (Photosynthesis)

A series of molecules that electrons move through, releasing energy that is stored as ATP.

Photolysis

The process in which $H_2O$ molecules are broken apart, providing replacement electrons, $H^+$ for NADPH, and releasing $O_2$.

Calvin Cycle

Another name for the light-independent reactions occurring in the stroma; uses $CO_2$, ATP, and NADPH to produce glucose.

Cellular Respiration

Process by which all organisms break down glucose to gradually produce energy in the form of ATP ($C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$).

Aerobic Respiration

Respiration occurring when oxygen is available, involving all three steps (glycolysis, Krebs cycle, and electron transport chain) and yielding about $36$ ATP.

Anaerobic Respiration

Respiration occurring when oxygen is not available, consisting of glycolysis followed by fermentation, yielding only $2$ ATP.

Glycolysis

The initial step of cellular respiration in the cytoplasm where a glucose molecule is broken into $2$ pyruvic acid molecules, yielding $2$ ATP and passing electrons to $NAD^+$.

Krebs Cycle

Stage of aerobic respiration in the mitochondria where pyruvic acid breaks down, releasing $CO_2$, ATP, and high-energy electrons to FAD and $NAD^+$.

Electron Transport Chain (Respiration)

Stage in the mitochondria where high-energy electrons are passed along a series of molecules to transport $H^+$ ions, using $O_2$ to form $H_2O$ and generating the most ATP.

ATP Synthase

Molecule turned by $H^+$ ions moving back across the mitochondrial membrane that generates large amounts of ATP.

Fermentation

Process occurring after glycolysis when oxygen is not available; recycles $NAD^+$ so it does not run out and glycolysis can continue.

Alcoholic Fermentation

Type of fermentation used by yeast that converts pyruvic acid into ethyl alcohol, $CO_2$, and $NAD^+$.

Lactic Acid Fermentation

Type of fermentation used by humans for quick energy and in foods like yogurt and pickles, producing lactic acid and $NAD^+$.