bio test 3

The ability to do work or bring about a change

Kinetic and potential

 the energy of motion (like water flowing over a waterfall

stored energy whose capacity to do work is not being used at the moment

Why energy flows thru ecosystems and thru cells

• 1st Law of Thermodynamics (Conservation) - Energy cannot be created or destroyed, but may be changed in form
• 2nd Law of Thermodynamics (Entropy) - Nature tends toward greater randomness or disorder (greater entropy)
• * Living systems maintain the order only through the constant intake of energy

The energy that must be added to cause molecules to react with one another

Disorganization in the universe. Usable energy is lost when there is a changeLost energy increases disorder. When things are more organized they are less stable.

 Usable energy is lost in the form of heat

An inhibitor can temporarily turn an enzyme off and denaturing an enzyme will turn it off forever

organic catalysts, usually proteins, that speed up chemical reactions

the reactant in the enzymatic reaction

the region of contact between the substrate and enzyme where the reaction occurs

used up in a reaction

• temperature
• pH
• substrate concentration

slow chemical reactions

speed chemical reactions

denaturation

the energy that must be added to cause molecules to react with one another

they lower the amount of energy of activation

 require you to put energy in (cellular respiration)

yields energy ATP  ---> ADP + P

 available to perform work

 Enzyme is induced to undergo a slight alteration to achieve optimum fit for the substrates. Change shape to fit a 2nd substrate, to allow the 2 substrates to bind together (dehydration reaction)

 either substrate or inhibitor can bind to active site (substrate and inhibitor are competing for active site)

 inhibitor binds at allosteric site. (location other than active site)

reversal or stopping of a metabolic pathway due to non-competitive inhibition by a product

 starting the metabolic pathway

loss of an electron; removal of hydrogens; release energy

gain of an electron (gain a negative charge); store energy

reduction (redox) reactions: Electrons pass from one molecule to another

tend to store energy, form larger molecules (ants build stuff up)

- tend to release energy, break molecules (cats break down mice)

• membrane-bound carrier proteins in mitochondria and chloroplasts accept hydrogens from one another so they can be released as energy to do work.
• Starts with high-energy electrons. Electrons are passed from carrier to carrier.
• Ends with low-energy electrons and high-energy ATP

The formation of ATP by hydrogen ions moving thru the membrane

carbon dioxide and water

6CO₂ + 6H₂O + _{solar energy} → C₆H₁₂O₆ + 6O₂

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + _Energy

chemical bonds of organic molecules like glucose

chloroplasts

thylakoids

• light reactions
• Calvin cycle

• light is converted from solar energy into a temporary form of chemical energy (red and blue light are absorbed; NOT green)
• takes place in the thylakoids

• a series of chemical reactions that take the molecules from light reactions and convert them into molecules better suited to the long term storage of energy
• takes place in the stroma
• light is NOT necessary for these reactions

• Fixation of carbon dioxide (fixing it into a carbohydrate)
• Reduction of carbon dioxide (adding hydrogens to it) makes PGAL
• Regeneration of RuBP

• chlorophyll a
• chlorophyll b
• Carotenes
• Xanthophylls

• Noncyclic pathway: high energy electrons go thru electron transport chain and are not recycled. yeilds ATP + NADPH
• Cyclic pathway: high energy electrons go thru electron transport chain and then is re-energized and is recycled yields ATP (only)

 plants do not need light for photosynthesis because carbon fixation and calvin cycle occur at different times in different places

live in hot environments. Fix carbon at night. Keep from drying out by dividing when they bring in carbon dioxide from when they release it to the calvin cycle

is NADP

is NAD

• blue and red
• green

is the process cells use to obtain energy from the food molecules that have been brought into the cell, this energy is then stored in the form of the molecule ATP.

Electrons are removed from substrates and received by oxygen, which combines with H+ to become water. Glucose is oxidized and O2 is reduced . Occurs around and in the mitochondria

• 1. Glycolysis
• 2. Kreb's Cycle
• 3. Electron transport chain

glucose (a 6-carbon compound) is broken down into two molecules of pyruvic acid (a 3-carbon compound). This process occurs in the cytoplasm of the cell.

• acetyl coenzyme A (produced from pyruvic acid) is further broken down, and the hydrogen is removed from the carbon skeleton.
• The hydrogens are picked up by the hydrogen carriers NAD and FAD and taken to the electron transport chain.
• Kreb's cycle occurs in the mitochondrion.

the hydrogen proton and electron are separated to form a chemical gradient. This provides the energy for the formation of ATP. Electron transport occurs in the mitochondrion.

• Glycolysis - 2 ATP molecules
• Kreb's Cycle - 2 ATP molecules
• Electron Transport Chain - 32 ATP molecules
• total: 36 molecules of ATP from the respiration of 1 glucose

• Occurs in cytoplasm outside the mitochondria; anaerobic
• Advantage: quick burst of ATP for muscular activity
• Disadvantages:Lactate and alcohol are toxic to cells. Yeast die from the alcohol they produce by fermentation

chloroplast

mitochondria

glucose