Biology Exam

please dont fail

energy flow

sun (energy) → plants (producers) → animals (consumers) → bacteria or fungi (decomposers) → heat

metabolism

sum of all the breaking down and building up chemical reactions in an organism, as related to energy

catabolism

breaking down

anabolism

building up

First Thermodynamic Law

Energy cannot be created or destroyed, only transformed and transferred into different forms of energy

Second Thermodynamic Law

energy transformations are associated with increases in entropy (measure of unavailable energy)

Types of energy

kinetic - motion

potential energy - stunned

chemical potential - energy stored in chemical bonds

heat - disorganized

light

vibrational

radiation

matter (mass)

Universe Favors two things (spontaneously)

1) moving towards lower energy states

2) moving towards higher entropy states

Low entropy

highly ordered; life can only happen if other things become disordered so that the laws of thermodynamics are obeyed

free energy

free to work with

What is G in G=H-(T*S)

available freed energy

What is H in G=H-(T*S)

total energy in a system

What is T in G=H-(T*S)

temprature

What is S in G=H-(T*S)

entropy (unavailable energy/disorder)

Delta G < 0

spontaneous, energy release, favorable, exergonic reaction

Delta G > 0

nonspontaneous, energy needing, not favorable, endergonic reaction

Delta G = 0

never happens → no energy

How does ATP power cellular work?

by coupling exergonic reactions to endergonic reactions

energetic coupling reaction

an energy requiring reaction can only occur if its simultaneously coupled to an energy

how do enzymes speed up metabolic reactions

by lowering energy barriers

how do enzymes speed up reactions

lowering activation energy not by changing delta G of reaction

normal binding

enzyme, active site and substrate, good

competitive inhibition

enzyme, competitive inhibitor in active site, bad

noncompetitive inhibition

Inhibition in different active site, slows down the reaction

Allosteric activators

four subunits and 4 regulatory sites together, with an activator its stabilized and active

cooperativity

enzymes working together

negative feedback inhibition

regulates enzyme pathways the last product needed tells it to stop

autotrophs (producers)

energy from the sun

heterotrophs (consumers)

energy from organic materal

breathing

gas exchange

cellular respiration

making energy by breaking down sugar

oxidation

Loss of electrons from organic molecules, gives off energy, catabolic and exergonic (breaking down glucose)

reduction

gain of electrons from organic molecules, need energy, anabolic and endergonic ( photosynthesis)

what are redox reactions

occur simultaneously (reduction and oxidation)

why is glucose a good source of energy?

because it is electron dense and when oxidized energy is released

What shuttles molecules and helps keep the production of energy slow, controlled and efficient

enzymes and electrons

aerobic cellular respiration

human cells harvest energy when oxygen is used in the process

anaerobic cellular respiration

less efficient way of harvesting energy can occur for short periods without oxygen

cellular respiration

oxidizes glucose most efficiently to yield energy and uses a step-wise approach via molecules called NAD+ and FAD to safely move electrons away from the glucose oxidation, made of 4 steps (glycolysis, movement of pyruvate into the mitochondria, the Krebs cycle and oxidative phosphorylation using an electron transport chain to make ATP from glucose

hexokinase

prevents glucose from leaving cell by adding a phosphate

PFK

controls the level of ATP adds another phosphate to split glucose

GAPDH

starts play off and generates 2 NADH

pyruvate

end product of glycolysis and goes to krebs cycle

NADH

full energy carrier and drops off energy from energy

NAD+

picks up electrons and turns into NADH

energy investment(stepss 1-5)

input 2 atp

output 2 adp and 2 phosphate

Energy payoff (steps 6-10)

input 4 ADP and 2 NAD+

output 4 ATP 2 NADH

substrate level phosphorylation

old-fashioned way of making atp ADP goes into the active site and gets a phosphate group from a 2nd substrate, creating ATP

krebs cycle

The remaining two carbons get turned into CO2, which gets exhaled, and from the oxidation of the carbons, three NAD+ turn into 3 NADH, the krebs cycle also produced one ATP from ADP and a phosphate and one FAD turns into FADH2 the FADH2 and the NADH go to the next step in cellular respiration

movement of pyruvate into the mitochrondria

Pyruvate is polar, meaning it needs an enzyme channel to enter the mitochondrial matrix, and three pyruvate carbons enter, one turns into CO2, and the other two are ushered to go on to the krebs cycle

electron transport chain and Oxidative phosphorylation

from the NADH and FADH2, they are oxidized and lose their electrons that are pumped through protein pumps to the intermembrane space of the mitochondria

Chemiosmosis

The high concentration of electrons in the intermembrane space of the mitochondria powers the spinning of the ATP synthase to generate ADP and phosphate into ATP(energy)

anaerobic respiration (fermentation) - no oxygen

only glycolysis and not sustainable for ATP production (kicks in during fight or flight)

what do yeast and bacteria use during fermentation?

they use ADH that converts pyruvate to ethanol to allow only glycolysis to continue

what due humans mainly use during fermentation

they use LDH that converts pyruvate to lactic acid to allow only glycolysis to continue; humans have ADH but is mainly used to break down poisonous alcohol

the hydrolysis of ATP and what amount of energy does it give off

ATP+H20 → ADP + Pi. and it gives off -7.3 kcal/mol