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Flashcards in Week 4 - energy and metabolism Deck (25)
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1

Kinetic energy

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

2

potential energy

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

3

chemical energy

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

4

chemical bonds

- 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

5

heat/ thermal energy

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

6

First law of thermodynamics

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

7

Second law - thermodynamics

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

8

chemical reactions - endogenic

- 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

9

Endergonic

reactions that form bonds to build molecules require energy input

10

Exergonic

- reactions that break bonds to release energy stored in bonds

11

chemical reactions - spontaneous

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

12

activation energy

- 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

13

enzyme

protein that acts as a catalyst → speeds up a chemical

14

substrate

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

15

enzyme-substrate eg.

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

16

energy - cellular level

- 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

17

chemical reactions - metabolism

- 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

18

ATP cycles

- 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

19

ATP and coupling

- 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

20

competitivity

competitive: blocks access point to active site
non-competetive: changes shape of active site

21

enzymes - optimum temperature

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

22

enzymes - temperature

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

23

enzymes - pH

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

24

free energy (delta G + metabolism

- 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

25

Free energy - reactions

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