Energy And Respiration Flashcards
Why do living organisms need energy?
To Work!
Examples of work:
Anabolic Reactions for example protein synthesis, synthesis of glycogen (glycogenesis), DNA replication, polymerisation.
Active transport: for example Na+-K+ pump, movement of vesicles in exo/endocytosis.
Movement: For example muscle contraction, cilia/flagella, movement of chromosomes
Maintenance of a constant body temperature in warm blooded animals for example endotherms.
Bioluminescence/electrical discharge for example in jellyfish and electric eels.
What is the meaning of anabolic reactions?
Anabolic reactions is the building of large molecules from smaller molecules using energy.
What is the meaning of catabolic reactions?
Catabolic reaction is when a large molecule is broken down into smaller molecules and releases energy.
Describe the structure of ATP
Adenosine triphosaphate
It is a phosphorylated nucleotide.
Its structure has three components.
1) Adenine (organic, nitrogenous base)
2)Ribose sugar (Pentose sugar)
3)Three phosphate groups
1+2=adenosine (nucleoside)
What are the chemical properties/characteristics of ATP?
- Small
- Water-Soluble
→Easily transported around the cell - Readily hydrolysed/lose phosphate to release energy
- Small packets of energy released at one time.
- ATP can be synthesised and broken down quickly
→High turnover rate
This makes it ideal as an energy currency in all organisms.
What is the roles/functions of ATP as a universal link/intermediate energy molecule:
a)The universal link/Intermediate energy molecule
* Between energy-giving reactions and energy-requiring reactions.
*Examples of energy-giving reactions: aerobic respiration aka complete oxidation of glucose.
→Gives a very large quantity of energy 2870KJ per molecule.
C6H12O6+6O2→6CO2+6H2O+2870KJ
Hydrolysis of ATP→Energy
* But energy transfers are inefficient
→Excess energy is lost at different stages in the multi-step reaction.
→As thermal/heat energy
What is the roles/functions of ATP as the energy currency of the cell:
b)ATP is the energy currency of the cell
* Energy giving/yeilding-reactions are linked to the production of ATP first,then energy requiring reactions.
ATP is NOT an energy storage molecule
What is an energy storage molecule:
An energy storage molecule stores energy in the form of chemical potential energy. For example:
Short term-Glucose,Sucrose
Long term-Glycogen,starch,triglyceride
What is the role of ATP as an immediate donor of energy?
ATP is an immediate donor of energy to reactions requiring energy.
Chemical equation of ATP hydrolysis:
ATP⇌ADP+Pi+30.5KJ
Where Pi is inorganic phosphate or
ATP+H2O ⇌ ADP + H3PO4 + 30.5KJ
Reactions are reversible
ATP can be synthesized and broken down quickly
Rate of turnover/interconversion of ATP is high
For example at rest we use about 40kg of ATP in 24 hours
Removal of 1st phosphate group ATP→ADP
→30.5KJmol-1 energy released
Removal of 2nd phosphate group from ADP→AMP
→30.5KJmol-1 energy released
Removal of the last phosphate group from AMP→Adenosine
14.2 KJmol-1 energy released
Where is ATP synthesised from?
ATP is synthesized from energy yielding reactions.
For example the oxidation of glucose and cellular respiration or light dependent stage in photosynthesis.
In a series of reactions.
What is respiration?
Respiration is a process where organic molecules such as glucose amino acid glycerol or fatty acids are broken down in a series of stages.
To release energy.
Which is used to synthesize ATP.
The two types are
1) aerobic respiration
2) anaerobic respiration
What is aerobic respiration and what are the four stages and their location?
Aerobic respiration is the breakdown of organic molecules for example glucose, fatty acids, glycerol and amino acids
to release energy
which is used to synthesize ATP
in the presence of oxygen.
There are four stages in aerobic respiration of glucose:
1) Glycolysis-Cytoplasm
2)Link Reaction-Mitochondrial matrix
3)Krebs Cycle-Mitochondrial matrix
4) Oxidative Phosphorylation-Inner mitochondrial membrane/cristae
Why is the oxidation of glucose in cellular respiration a multi-step reaction?
Each step releases a small quantity of energy(ATP) to:
1) Allow precise control
2)Cells could not fully harness total energy released if all were made available in one instant.
Also, reactions do not happen easily:
because glucose is a stable substance
It requires a high activation energy for the reaction to take place.
To overcome this:
1) Usage of enzymes to lower activation energy
2)Raising energy level of glucose by phosphorylation
➝more reactive
What are the steps in glycolysis or the glycolytic pathway?
1)Glucose (6C) is phosphorylated (phosphorylation)
*By 2 ATP
*Form hexose/fructose diphosphate (6C)
*This raises chemical potential energy of glucose
*Provide activation energy for split
2)Fructose diphosphate breaks down to 2 triose phosphate (3C) (lysis)
*6C➝2x3C
3) 2 hydrogen atoms are removed
*2 reduced NAD formed
*This is a dehydrogenation/oxidation reaction
4) 4 ATP produced (ATP is synthesized through substrate-level phosphorylation)
*4 ATP-2 ATP=net gain of 2 ATP
*Chemical potential energy is released from intermediate steps.
5) 2 pyruvate (3C) produced
Initial reactants:
1 Glucose (6C)
2 ATP
4 ADP, 2 NAD
Final products per molecule of glucose:
*2 pyruvate (3C)
*2 NADH
*4 ATP➝But 4-2=net gain of 2 ATP only!
The whole process involves many enzymes at each step
What are the different types of hydrogen acceptor molecules?
They are also called hydrogen carrier molecules:
You will learn 3 types:
1. NAD-nicotinamide adenine dinucleotide (used in respiration)
2. NADP-nicotinamide adenine dinucleotide phosphate) used in photosynthesis)
3. FAD-Flavin adenine dinucleotide (used in respiration)
They are all coenzymes= a non protein complex organic substance that is required for an enzyme’s activity.
