module 2 bioa01

ways that organisms gain energy from enviroment

1. by harvesting energy through sunlight (phototrophs)
2. by harvesting energy from chemical compounds (chemotrophs)

difference between catabolism and anabolism

1. catabolism is set of chemical reactions that break down macromolecules into smaller units (releasing energy ATP)
2. anabolism is set of chemical reactions that build macromolecules from small units and require input energy (ATP)

Metabolism

set of biochemical reactions that transform molecules and transfers energy

kinetic energy

energy of motion

potential energy

stored energy

ATP (adenosine triphosphate)

energy-carrying molecule, captures energy obtained from food breakdown and releases it to fuel other cellular processes

what is the core of AtP

adenosine

what is the relationship between strength of a covalent bond and amount of chemical energy it contains?

chemical energy is a form of potential energy. the Stronger the covalent bond, the less chemical energy it contains, and weaker the covalent bond, the more chemical energy it contains

thermodynamics

branch of physics that deals with relationship between heat and other forms of energy

first law of thermodynamics

energy is neither created nor destroyed (constant amount of energy)

second law or thermodynamics

transformation of energy is associated with an increase in the degree of disorder in the universe

Entropy

the amount of disorder is a system

disorder

when kinetic energy is changed from potential energy, the amount of disorder increases

chemical reaction

involve the breaking and forming of bonds

Gibbs free energy (1)

the amount of energy available to do work

Gibbs free energy (2)

in chemical reaction we can compare the free energy of a reactants and products to determine wither the reaction releases energy that is available to do-work (free energy of product - free energy of the reactants

Exergonic

Chemical reactions with a negative G, that release energy

Endergonic

A chemical reaction that with a positive G, that requires the input of energy in order to proceed.

spontaneous

reaction releases energy

Enthalpy

The total amount of energy in a system

Entropy

A measure of disorder or randomness.

equation for total amount of energy

(H) = energy available to do work (G) + energy lost to entropy (TS)

absolute temperature

temperature measured on the kelvin scale

how to determine if the reaction is spontaneous or not?

The absolute values of the energy and enthalpy changes determines whether G is positive or negative (spontaneous or not)

relationship of energy equation

1. if G is positive H is positive, TS is negative
2. if G is negative His negative, TS is positive

Hydrolysis reaction example

ATP + H2O→
ADP + Pi (inorganic phosphate)

hydrolysis

chemical reaction, where water molecules split into a proton (H) and hydroxide (OH)

energetic coupling

The driving of a non-spontaneous reaction (POSITIVE G) by a spontaneous reaction (NEGATIVE G)
the net G of the two reactions is negative

how does increasing the temperature affect the change in free energy (G) of a chemical reaction ?

increasing the temperature, increases value of TS, which decreases G. Meaning increasing temperature will make it more likely that a reaction will proceed without a net input of energy

How can hydrolysis of ATP drive non spontaneous reactions in a cell ?

the hydrolysis of ATP releases energy. This energy can be used to drive non spontaneous reactions if the total (G) of the entire path is negative

Enzymes

protein that functions as a catalyst to accelerate the rate of a chemical reaction

allosteric enzymes

an enzyme that is activated or inhibited when binding to another molecule changes its shape

cellular respiration

a series of catabolic reactions that convert energy in fuel molecules (glucose) into ATP
(produces carbon dioxide as waste)

aerobic respiration

Respiration that requires oxygen

anaerobic respiration

Respiration that does not require oxygen

cellular respiration equation

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

what molecules have a large amount of potential energy

carbohydrates, and lipids

What molecules have less potential energy in their bonds?

carbon dioxide and water

substrate-level phosphorylation

A way of generating ATP in which a phosphate group is transferred to ADP from an organic molecule, which acts as a phosphate donor or substrate.
(only produces 12% of ATP)

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.
(produces 88% of ATP)

electron carriers

A molecule that carries electrons (and energy) from one set of reactions to another.

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

oxidation-reduction reaction

reaction involving the loss and gain of electrons between reactants

oxidation

loss of electrons

reduction

gain of electrons

two important electron carriers are.....

nicotinamide adenine dinucleotide, and adenine dinucleotide

Stage 1 of cellular respiration

glucose, is partially broken down to produce pyruvate, and energy is transferred to ATP and reduced electron carrier
(glycolysis)

stage 2 of cellular respiration

pyruvate is oxidized to another molecule called acetyl-coenzyme A, producing reduced electron carriers and releasing carbon dioxide

stage 3 of cellular respiration

acetyl-CoA is broken down and carbon dioxide is released

Stage 4 of cellular respiration

set of metabolic reactions that occur by passing electrons along an electron transport chain to the final electron acceptor, oxygen
large amount of ATP is produced

change in free energy in cellular respiration

glucose is oxidized through a series of chemical reactions, releasing energy in the form of ATP and reduced electron carriers

Glycolysis

in eukaryotes takes place in the cytoplasm

pyruvate oxidation, the citric acid cycle, and oxidation phosphorylation

takes place in the mitochondia

glucose is anaerobic

because oxygen is not consumed

what is the overall equation of glycolysis

Glucose + 2ADP + 2NAD+ +2Pi -->
2ATP + 2pyruvate + 2NADH +2H20 + 2H+

At the end of glycolysis, but before the subsequent stages in cellular respiration, which molecules contain some of the chemical energy held in the original glucose molecule?

at the end of glycolysis, the energy in the original glucose molecule is contained in pyruvate, ATP, and NADH

Mitochondria

rod shaped organelles surrounded by a double membrane

the oxidation of pyruvate connects glycolysis to the __________________ cycle

citric acid cycle

intermembrane space

the space between the inner and outer mitochondrial membranes

mitochondial matrix

the space enclosed by the inner membrane of the mitochondria

pyruvate is transported into the ____________________, where it it converted into acetyl-CoA

mitochondrial matrix

the synthesis of one molecule of acetyl-CoA from pyruvate results in the formation of

one molecule of carbon dioxide, and one molecule of NADH

At the end of pyruvate oxidation, but before the subsequent stages of cellular respiration, which molecules contain the energy held in the original glucose molecule?

at the end of pyruvate oxidation, the energy in the original glucose molecule is contained in acetyl-CoA and NADH.

During the citric acid cycle:

fuel molecules are completely oxidized, acetyl-CoA is completely oxidized to a carbon dioxide

citric acid cycle is also called

the kerbs cycle, and the TCA cycle

citric acid cycle produces:

one ATP, three NADH, and one FADH2

At the end of the citric acid cycle, but before the subsequent stages of cellular respiration, which molecules contain the energy held in the original glucose molecule?

at the end of the citric acid cycle, the energy in the original glucose molecule is contained in ATP, NADH, and FADH2

electron transport chain:

is made up of four large protein complexes, that are embedded in the inner mitochondrial membrane

the mitochondrial membrane

consists of the highest concentrations of protein found in eukaryotic membranes

oxygen accepts electrons at the end of the electron transport chain and is:

reduced to from water
O2 + 4e + 4H ---->
2H2O

O2 + 4e + 4H ---->
2H2O

catalyzed by complex IV

protein gradient have two components

1. chemical gradient that results from the difference in concentration
2. electrical gradient that results from the difference in charge between the two sides of the membrane

oxidation of the electron crarriers NADH and FADH2, leads to

the generation of a proton electrochemical gradient. This gradient is a source of potential energy used to synthesis ATP

animals breathe in air that contains more oxygen than the air they breathe out. Where is oxygen consumed?

oxygen is consumed in cellular respiration. Oxygen is the final electron acceptor in the electron transport chain and is converted to water

ATP synthase

an enzyme that couples the movement of protons through the enzyme with the synthesis of ATP

When oxygen is present

pyruvate is converted to acetyl-CoA, which then enters the citric acid cycle

When oxygen is not present

pyruvate is metabolized along a number of different pathways,
played an important role in the early evolution of like on earth

Fermentaton

variety of metabolic pathways that produce Atp from the partial oxidation of organic molecules without oxygen

Two major fermentation pathways are

lactic acid fermentation and ethanol fermentation

lactic acid fermentation

occurs in animals, and bacteria, electrons from NADH are transferred to pyruvate to produce lactic acid and NAD

lactic acid fermentation equation

Glucose + 2 ADP+ 2 Pi→ 2 lactic acid +2 ATP+2H2O

ethonal fermentation

occurs in plants and fungi, pyruvate releases carbon dioxide to form acetaldehyde, and electron from NADH are transferred to acetaldehyde to produce ethanol anf NAD

ethanol fermentation equation

Glucose+2ADP+2Pi→2ethanol+2CO2+2ATP+2H2O

in both fermentation pathways:

NADH is oxidized to NAD

bread making involves ethanol fermentation and typically uses yeast, sugar, flour, and water. Why are yeast and sugar used?

Yeast cells are eukaryotes. In bread making, yeast can use sugar as a food source for ethanol fermentation. The carbon dioxide produced in the process causes the bread to rise. The ethanol is removed in the baking process

excess glucose is stored as ___________ in animals

glycogen

excess glucose is stored as ____________ in plants

starch

carbohydrate in your diet are digested to produce:

a variety of sugars

some are monosaccharides (fructose, mannose, and galactose) with one sugar unit

Others are disaccharides (maltose, lactose, and sucrose) with two sugar units

the disaccharides are hydrolyzed into monosaccharides, which are transported into cells

fatty acids and proteins

are a useful source of energy

oxidation of fatty acids:

produce large amount of ATP
example:
palmitic acid

When ATP levels are high

the cell has a high amount of free energy and is poised to carry out cellular respiration

When ATP levels are low

pathways that generate ATP are activated

level of ATP inside a cell can therefore be an indicator of:

of how much energy a cell has available

how does muscle tissue generate ATP during short term exercise?

muscle tissue generates ATP during short-term exercise by converting stored glycogen to glucose

Photosynthesis

energy and carbon are incorporated into carbohydrates

Calvin Cycle

a three step process that uses carbon dioxide to synthethize carbohydrates

Equation for photosynthesis

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

photosynthesis is a redox reaction

Photosystems

1. absorption of light by protein pigment known as photosystem

photosystems use absorbed light energy to drive redox reaction

Where does O2 come from?

water, not carbon dioxide

in eukaryotes photosynthesis takes place in

chloroplasts