LECTURE 1 Flashcards by Carmen Abraham

What are the 6 main forms of energy storage?

chemical (food)
Mechanical (kinetic)
Thermal (body heat)
Electrical (firing neurons)
Radiant (light)
Atomic (nuclear fission)

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What is energy regarding human movement?

it is based on an energy shift. Producing a given force over a given distance. Without energy, no work can be done (no muscle contraction)

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Where does energy come from?

energy cannot be created. Every new form of energy is a transfer from another. (water moving through a turbine creates electrical energy)

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How is energy measured in humans and where do we get it from?

Food. Measured as calories or Kcal.
Carbs = 4kcal
Protein = 4kcal
Fat = 9kcal

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How efficient are humans at energy transfer? What happens to the rest of the energy?

only 25% at maximum.

Increase in temperature during exercise, this helps speed up reactions.

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what do chemical reactions do?

absorb and release energy

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What is needed for a chemical reaction to start?

Activation energy

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What does ATP stand for?

Adenosine Triphosphate

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What is ADP?

Adenosine Diphosphate

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What does exothermic mean?

Exo = to release
Thermic = heat

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Define exothermic reactions

chemical reaction that releases more energy than it absorbs. usually as heat and light

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What does endothermic mean?

endo = absorb
thermic = heat

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Define endothermic reactions

chemical energy that absorbs more energy than it releases such as photosynthesis (takes in sunlight, to create sugar and glucose for plant food)

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what is a catalyst?

a substance that decreases the activation energy needed to start a chemical reaction
So the activation energy is less with a catalyst.

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what makes up proteins?

amino acids (they are attracted to one another and make a specific shape to perform specific functions

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What are the human catalysts?

enzymes. they are used for every chemical reaction in the body

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how do you determine if it is an enzyme?

they end in ase

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what are enzymes?

they are proteins (twist, fold and bend into a specific shape).

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why is the enzyme shape important?

the substrate will bind to particular areas (think of a lock and key), and this becomes the active site

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what binds to enzymes?

substrates

what does the enzyme do to the substrate?

the enzyme weakens and breaks the bonds of the substrate then releases it.

why are enzymes important?

they significantly speed up chemical reactions by decreasing the activation energy required (think of the graph with the two lines)

What is a modulator site?

some enzymes have a modulator site which changes the configuration of the enzyme which then changes the rate of reaction

What are stimulants?

Speed up a reaction

What are inhibitors?

slow down a reaction (drugs for cancer patients)

what is thermodynamics?

the study of energy transfer

what are the 3 laws of thermodynamics?

1st law: conservation of energy 2nd law: disorder, randomness or spread of energy 3rd lawn: entropy at absolute zero (-273oC is zero)

explain the first law of thermodynamics

energy cannot be created or destroyed. It is transferred from one state to another without being depleted. (energy in -food = energy out + heat + energy)

explain the second law of thermodynamics?

it is the spread of energy.

what does entropy mean?

disorder and is written as (S) an example is a messy room, it will become messy, but not become neat... the disorder increases, the energy is spread. more energy dispersal = more entropy.

What is another example of the second law - entropy?

A hot drink in a room temperature will cool and equilibrate with the room by spreading energy into its environment.

define energy

the ability to perform work, emerges only when a change takes place

what are the 3 main forms of energy transfer?

mechanical, chemical and transport

How long does ATP provide energy from muscle storage?

3-5 seconds

explain the PCr system.

The body uses up the free ATP for energy first but then creatine is broken down and donates its phosphate to ADP to resynthesise ATP.

how long does the phosphate system last?

8-10 seconds | weightlifting, powerlifting, gym work for heavy lifting less than 5 reps

what is a coupling reaction?

where both exothermic and endothermic reactions occur. Such as photosynthesis - the sun exothermically releases heat but the leaf endothermically absorbs it to create photosynthesis - roughly.

what is enthalpy?

accounts for the loss of energy in a spontaneous reaction - energy lost into the atmosphere. Change in energy during a reaction = enthalpy

how is Enthalpy represented?

how is change in enthalpy represented?

^H (triangle before the h)

what is Gibb's free energy?

usable energy - energy to make muscles contract, systems run. = LIFE

How is Gibbs free energy represented?

G | -^G denotes an exothermic reaction

what does equilibrium mean?

refers to a system that is in a standstill. reactions will proceed until equilibrium is reached AC+BD = AD+BC If you add more AC & BD to the left, the reaction will continue until it is even on both sides.

how do you represent equilibrium?

Keq

If there is more product than reactant

its endothermic

if there is more reactant than product

its exothermic

whats the difference between anaerobic and aerobic?

aerobic is the use of oxygen

what does hydrolysis mean?

the breakdown of something using water

how is inorganic phosphate represented?