use energy and carbon from non-living sources to build their own food.
all plants, some protists, and some bacteria
perform the process of photosynthesis.
use energy from the sun and carbon from carbon dioxide to make sugars.
release oxygen in the process
use energy from inorganic chemicals such as methane and ammonia to build organic compounds.
some bacteria and many archaea are chemoautotrophs
takes place in plant cells in specialized structures (organelles) called chloroplasts.
anabolic process and is highly endergonic.
proceeds in two reaction stages: light-dependent reactions and light-independent reactions (carbon-fixation reactions)
light energy is absorbed by chlorophyll and other pigments located in the thylakoid membrane.
each type of pigment absorbs certain wavelengths of light and transmits or reflects the rest
chlorophyll absorbs blue and red wavelengths but transmits green, which is why leaves appear green.
carotenoid pigments absorb violet and blue and transmit yellow, orange and red.
the light energy excites electrons and boosts them to higher energy levels.
the electrons "fall" to a lower energy state, releasing energy that is used to make ATP
nucleotide molecule with 3 phosphate groups bonded to it.
it is called the energy currency of the cell.
the phosphates are negatively charged and it takes a lot of chemical energy to hold them together.
energy released in reactions is stored in bonds when ATP is formed from ADP and inorganic phosphate.
when the endmost phosphate group is broken off an ATP molecule, energy is released.
ATP molecule has three parts: sugar backbone, adenine nucleotide, and chain of three phosphate groups.
also called the calvin-benson cycle and carbon-fixation reactions.
using the energy from ATP made in the light-dependent reactions, and CO2 from air to water, glucose and other sugars are formed.
using carbon from environment to make stable organic compounds, such as sugars
releasing chemical energy
plants and all other organisms produce ATP by degrading (breaking apart) organic compounds such as glucose.
the products of photosynthesis (glucose) are used for metabolic fuel.
must take in energy and carbon from outside sources, cannot make their own food.
feed on autotrophs, one another, organic wastes, and remains.
animals, fungi, most bacteria, and many protists are heterotrophs
autotrophs & heterotrophs
all organisms, autotrophs and heterotrophs, must convert their food (organic compounds) to a form of chemical energy that can drive metabolic reactions (most commonly used is ATP)
transformation of chemical energy in food into chemical energy cells can use: ATP.
these reactions proceed the same way in plants and animals.
breakdown of glucose begins in the cytoplasm in a process called glycolysis.
a glucose molecule is broken down into two pyruvate molecules.
yields 2 ATP molecules
at this point life diverges into two pathways: aerobic cellular respiration (with oxygen) and anaerobic (no oxygen) cellular respiration (aka fermentation).
no additional ATP made- just the 2 from glycolysis
pyruvate converted to carbo dioxide and ethyl alcohol.
occurs in yeasts and some bacteria.
carbon dioxide makes bread rise.
pyruvate converted to lactic acid (lactate).
occurs in animals cells, and bacteria
aerobic cellular respiraton
2 more sets of reactions: citric acid cycle and electron transport chain.
occur in organelles within the cell called the mitochondria
citric acid cycle (kreb's cycle)
pyruvate from glycolysis is broken down, and CO2 is produced.
production of 2 more ATP
occurs in the mitochondrial matrix
NADH and FADH2 donate protons and electrons to the electron transport system (ETS).
the electrons are passed down the respiratory chain, which consists mostly of carrier proteins in the inner mitochondrial membrane
the energy released as the electrons are transferred is used to pump H+ out of the inner compartment of the mitochondria, setting up a concentration gradient.
the flow of H+ back through the protein channels, provides the energy for ATP synthesis
at the end of the ETS, oxygen picks up electrons and protons, becoming water.
32 ATP molecules are formed