CH21: GENERATION OF BIOCHEMICAL ENERGY

SPR26 OSU BIOPHRM 3312

oxidoreductases enzyme function

Catalyze oxidation-reduction reactions of substrate molecules, most commonly by addition or removal of oxygen or hydrogen

transferase enzyme function

catalyze the transfer of a functional group (e.g., phosphate, methyl, acyl) from one donor molecule to an acceptor

Hydrolases enzyme function

catalyze the hydrolysis of substrates, the breaking of bonds with water

lyases enzyme function

catalyze the addition or removal of a small group from a substrate without hydrolysis

isomerase enzyme function

catalyze the isomerization (rearrangement of atoms, changing the connections but no loss/gain) of a substrate

Ligases enzyme function

catalyze the bonding together of two substrate molecules

Cellular energy comes from food:

dietary carbs, fats/lipids, and proteins

_____ can be traced to energy from the sun or solar energy

bioenergy

photosynthesis definition

conversion of solar energy to chemical energy via the bonds of biomolecules w/in plants

what do humans obtain from animal and/or plant food sources?

chemical energy

human energy is utilized for ____ and ____ work or is ____

• mechanical

• chemical

• lost

define mechanical and chemical work (general)

synthesizing molecules and moving them across cell membranes, and muscle contraction

necessity of heat and its loss

necessary to maintain our body temp. w/ some energy, however, some heat energy is lost to the environment

too fast of an energy release is _____

bad; heat should be released in a controlled manner

where is energy stored

in the chemical bonds of food molecules

energy must be released _____, allowing the cell to capture it efficiently

gradually rather than all at once

organisms must be able to _____ and in readily _____ to meet immediate metabolic demands

• store energy both long term (e.g., as fat or glycogen)

• accessible forms (e.g., ATP)

how is a constant body temp maintained?

controlled amount of energy is release as heat, while the remainder is conserved for cellular work

main reason for gradual release of energy as heat from the body

To supply energy for non-spontaneous chemical reactions while preventing excessive heat loss and cellular damage.

food is the source of ___ and of ___ for animals

• energy

• nutrition

food is usually of ____ origins

plants and/or animals

what generally supplies 100% of our energy?

carbs, proteins, fats, proteins

Calories definition

measurement of food energy produced when you consume carbs, fats, and proteins

carbs and protein have ____ Calories per gram, and fats have ____ Calories per gram

4, 9

what are the 3 units of food energy?

calorie, Calorie, and kilojoule

calorie definition

(cal) = energy needed to raise the temp of 1 g of H2O by 1^oC

Calorie definition

(Cal) = 1000 calories or 1 kilocalorie (kcal)

energy content described on food labels refers to _____ unit of measure

kilocalories

how do you convert Calories to kilojoules (metric unit)

multiply the number of Calories by 4 (Ex: 10 Cal = 40 KJ)

shows the amount of food listed on a product’s food label

serving size

on a food label this shows the types of carbs in the food, including sugar and fiber

total carbohydrate

what types of food should you choose based upon food label?

• foods w/ more fiber, vitamins, and minerals

• food w/ less calories, sat. fat, sodium, added sugars, and avoid trans fat

metabolism definition

total of all biochemical rxns in an organism

2 components of metabolism

• anabolism

• catabolism

catabolism consists of degradative processes that ____, w/ a concomitant release of energy.

breakdown larger molecules into smaller molecules

in catabolism, how is the release of energy primarily captured?

captured in the form of ATP, w/ the breakdown products serving as precursors for biosynthetic pathways

anabolism comprises the biosynthetic processes that construct ____, and these rxns require an input of ____.

• larger, more complex molecules from smaller precursor molecules

• energy (ATP)

carbs consist of C, H, and O atoms, usually in the ratio of _____

C to H2O 1:1

fats and oils are chemically called ______

triacylglycerols

triacylglycerols are what?

tri-esters of one glycerol and 3 usually different fatty acids

proteins are polymers of ______ w/ varying composition and may contain N and S.

standard amino acids

what are proteins NOT normally used for

energy storage

ID: C6H12O6

glucose, an aldohexose

ID this structure:

glucose, an aldohexose

ID this:

triacylglycerol

• note location of ester bonds and acyl groups

biomolecules ←→ building blocks + ATP

what is the for forward and reverse rxns called?

• forward: catabolism

• reverse: anabolism

building blocks of carbohydrates are

simple sugars and monosaccharides

building blocks of fats and oils

glycerol and fatty acids

building blocks of proteins

20 standard amino acids

carbohydrate form stored in our body

glycogen in the muscles & liver (limited amounts)

fats and oils form stored in our body

fats in adipose tissues (unlimited)

protein form stored in our body

none is specially used as an energy storage

bioenergetics is the branch of biochemistry that focus on _____, often by producing or consuming ____.

• how cells transform energy

• adenonsine-5’-triphosphate (ATP)

gibbs free energy (G) is the portion of the total chemical energy stored in the chemical bonds that is ________

available to do work (and only the bonds that are available to do work, not all bonds!)

larger molecules are more complex with more ______, and higher ________ than smaller molecules

• bonds and energy

• G values

sucrose has ____ than glucose and fructose

more energy (due to larger size)

delta G = ?

G products - G reactants

a rxn is generally considered favorable when energy is ____; that is when delta G is ____.

• released

• negative

free energy content associated with

• reactants/substrates

• activation complex

• activation energy

• products

• change of energy

activation energy definition

energy required for a rxn to occur

the ± sign of delta G indicates the _____ of a chemical rxn and determines whether a rxn is _______

• direction

• spontaneous or not

negative delta G

• spontaneous in the forward direction

• exergonic rxn

delta G = 0 meaning

reactants and products are at equilibrium

positive delta G

• reactants are at lower energy than products

• non-spontaneous in forward direction

• endergonic rxn

glucose is ________ to produce CO2 and H2O

oxidized (oxidation reaction)

glucose is more complex than its breakdown products → the free energy of the reactants > products. The delta G change is _______.

negative

when delta G is negative, the rxn releases energy, is ____, thermodynamically favorable, and can occur spontaneously.

exergonic

____ is a metabolic process that builds up complex molecules from simpler ones, requiring input of energy.

anabolism

glucose is synthesized from CO2 and H2O by _____

photosynthesis

delta G of an anabolic rxn is ____.

positive

when delta G is positive, the rxn is ____, thermodynamically unfavorable, non-spontaneously, and requires an input of energy (i.e., solar energy).

endergonic

in glucose metabolism, photosynthesis is _____

anabolic
endergonic (energy input)
positive delta G value

in glucose metabolism, oxidation is _____

catabolic
exergonic (energy released)
negative delta G value

catabolic and anabolic rxns of glucose have the same delta G value but ______

opposite signs

anabolism utilizes ____ to make macromolecules and biopolymers

ATP

catabolism yields ____ when biopolymers and macromolecules are broken down to small molecules

ATP

ATP plays a central role in coupling ________ and _________ pathways in cellular metabolism

• anabolic (energy-consuming)

• catabolic (energy-releasing)

ID this rxn:

ATP + H₂O → ADP + HOPO₃^2- + H⁺ + energy

ATP hydrolysis

ATP hydrolysis rxn consists of what?

• negative delta G

• exergonic (energy release)

• spontaneous

ATP hydrolysis is the chemical process by which adenosine 5’-triphosphate (ATP) is broken down into _____ OR into _______.

• adenosine 5’-diphosphate (ADP) and inorganic phosphate (Pi)

• adenosine monophosphate (AMP) and pyrophosphate (PPi)

ATP is often called the ______ or an _______, transporting chemical energy w/in cells for metabolism.

• molecular unit of currency of intracellular energy transfer

• energy transporter

the energy of ATP is stored in _____ bonds.

two phosphoanhydride

adenosine-p-p-p → adenosine-p-p + Pi
adenosine-p-p → adenosine-p + PPi