Life Sciences - Cellular Respiration

What is cellular respiration?

The chemical process in which glucose is broken down into carbon dioxide, water and energy (as ATP) in the presence or absence of oxygen

metabolism

chemical processes in organisms controlled by enzymes

catabolic

a metabolic process where molecules are broken down into simpler ones to release energy

anabolic

the synthesis of complex molecules from simple ones

importance of energy

- growth

- cell division

- movement

- transport of substances

- active transport

aerobic respiration

respiration that requires oxygen

mitochondrion

organelle where respiration takes place

ATP

energy carrier molecule in cells

stages of aerobic respiration

-glycolysis

-krebs cycle

-oxidative phosphorylation

the glycolysis phase

-outside the mitochondrion; in the cytoplasm

-no oxygen is required

-glucose is broken down into smaller molecules, releasing small amount of energy

-releases high energy hydrogen ions used in the oxidative phosphorylation phase

the krebs cycle

-oxygen required

-inside the mitochondrion

-releases carbon dioxide and high energy rich hydrogen ions

-transports hydrogen atoms to the oxidative phosphorylation phase via enzymes

the oxidative phosphorylation phase

-in the mitochondrion; requires oxygen

-passes high energy hydrogen atoms from one enzyme to the next, releasing energy

-uses energy released to combine a phosphate molecule to an ADP molecule to form ATP (phosphorylation)

-oxygen=final hydrogen acceptor; binds with hydrogen to form water (waste product)

anaerobic respiration

respiration in absence of oxygen

fermentation

type of anaerobic respiration in yeast cells

alcoholic fermentation

breaking down of glucose in absence of oxygen, raises alcohol production in plant cells

lactic acid fermentation

breaking down of glucose in absence of oxygen, form lactic acid in animal cells

lactic acid

acid formed in muscle cells during anaerobic respiration

anaerobic respiration in animals

-lactic acid fermentation

-in muscles during intense exercise

-enables glycolysis in the cytoplasm

-lactic acid causes muscles to become tired and painful

-small amount of ATP

anaerobic respiration in plants

-alcoholic fermentation

-enables glycolysis in cytoplasm

-accumulation of of pyruvic acid

-breaks down pyruvic acid into ethanol and releases carbon dioxide