Week 4 - energy and metabolism

Question 1

Kinetic energy

Answer 1

Energy of motion/ movement associated w/ movement of organisms cells or organelles

Question 2

potential energy

Answer 2

energy, stored, available to do work due to structure or location.

Question 3

chemical energy

Answer 3

type of potential energy → available for release in a chemical reaction

Question 4

chemical bonds

Answer 4

• molecules like glucose and triglyceride → store energy in their bonds
• to release the energy, the cell breaks the bonds
• if the cell cannot capture the energy being released, it wil be lost as heat

Question 5

heat/ thermal energy

Answer 5

type of kinetic enrgy - associated w/ random movement of atoms or molecules

Question 6

First law of thermodynamics

Answer 6

• law of conservation of energy,
• energy cannot be created or destroyed
• can be transformed from one type to another

Question 7

Second law - thermodynamics

Answer 7

transfer or transformation of energy from one form to another. inc entropy or degree of disorder of a system

Question 8

chemical reactions - endogenic

Answer 8

• requires an input of energy
• the chief currency of all cells use their energy transactions in adenosine triphosphate (ATP_
• cells store and release energy in bonds of ATP

Question 9

Endergonic

Answer 9

reactions that form bonds to build molecules require energy input

Question 10

Exergonic

Answer 10

• reactions that break bonds to release energy stored in bonds

Question 11

chemical reactions - spontaneous

Answer 11

SPONTANEOUS CHEMICAL REACTIONS REQUIRE ACTIVATION ENERGY TO BE OVER COME OR REDUCED

Question 12

activation energy

Answer 12

• INITIAL INPUT OF ENERGY TO START REACTION
• allows molecules to get close enough to case bod rearrangement → can not achieve state where bonds are stretch

2 ways to overcome: LARGE AMOUNTS OF HEAT or using ENZYMES to lower activation energy

Question 13

enzyme

Answer 13

protein that acts as a catalyst → speeds up a chemical

Question 14

substrate

Answer 14

• molecules that bind to the enzymes active siite , where chemical reaction occurs.

Question 15

enzyme-substrate eg.

Answer 15

1. substrate, sucrose, consists of glucose & fructose bond together
2. substrate binds to the active site of the enzyme, forming an enzyme substrate complex
3. the binding of the substrate & enzyme places stress on the glucose- fructose bond & bond breaks
4. products are released & enzyme is free to bind w/ other substrates

Question 16

energy - cellular level

Answer 16

• subtances are modified, small molecules are combined to generate larger macromolecules & vise versa
• CELLULAR RESPIRATION extracts energy stored in fuel molecule → cells use this to perform various works

Question 17

chemical reactions - metabolism

Answer 17

• building complex molecules out of simple parts (monomers) forms new chemical bonds
• break complex molecules into simple parts break apart like chemical bonds → energy out

Question 18

ATP cycles

Answer 18

• ATP is a renewable resource that is regenerated by addition of a phosphategroup to adenosine diphosphate ADP
• the energy to phosphorylate ADP comes form catabolic reactions in the cell.
• the chemical potential energy ‘ temporarily’ stored in ATP drives cellular work

Question 19

ATP and coupling

Answer 19

• cells manage energy resources by ENERGY COUPING the use of an exergonic process to drive an endergonic one
• most energy couping in cells is mediated by ATP

Question 20

competitivity

Answer 20

competitive: blocks access point to active site

non-competetive: changes shape of active site

Question 21

enzymes - optimum temperature

Answer 21

CHANGES RATE OF MOLECULAR MOTION

• inc temp inc. molecular motion → inc. rate of catalyst
• OPTIMUM TEMP: temp at which the enzyme has the highest rate of catalysis
• dec temp. decreases molecular movement →decreases rate of catalysis

Question 22

enzymes - temperature

Answer 22

CAUSES CHANGE IN SHAPE OF ENZYME

• changes above optimum temp will affect enzyme structure
• can no longer bind to sunstrate and catalyse a reaction
• if temp increases and is too high, will cause enzyme to denature

Question 23

enzymes - pH

Answer 23

in basic enviro: acidic side chains could donate protons
in acidic enviro: basic side chains could accept protons

both events will change shape of enzyme → making it less able to bind w/ substrate, less able to catalyse reaction

Question 24

free energy (delta G + metabolism

Answer 24

• Free energy: energy that can be used to do work when chemical bonds are bropken
• chemical reactions break some bonds in the reactant and form new ones in products
• in some reactions the products contain less free energy than reactants & release excess energy

Question 25

Free energy - reactions

Answer 25

G = H-TS
g: gibbs free energy (thermodynamic function used )to describe ability of a system to undergo change
H: enthalpy
T: temp
S: entropy

a reaction can only occur spontaneously if the change in G for a given reaction is negative