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Flashcards in Topic 5 Deck (41):
1

Metabolism

The sum total of all biochemical reactions that occur in cells

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Endergonic

Result in a net input of use if energy

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Exergonic

Result in a net output of release of energy

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Energy transformations

Processes in which energy is changed from one form to another

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Anabolic

Chemical reactions in which atoms and molecules are brought together to make more complex molecules

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Catabolic

Reactions that break down complex molecules into simpler molecules

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Photosynthesis reaction

Endergonic and anabolic

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Cellular respiration reaction

Exergonic and catabolic

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Enzyme

Protein molecules that increase the rate of reactions that occur in living organisms

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Substrate

The compound being acted on by an enzyme

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Product

The compound obtained as a result of the enzyme action

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Enzymes are highly specific

Each enzyme acts on only one kind of substrate
Their active site can only bind to one specific substrate

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Enzyme substrate complex

When an enzyme controlled reaction takes place, the enzyme and substrate molecules become joined together for a short time or form an enzyme-substrate complex

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Are enzymes used up

No- available for reuse

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Denaturalising

When cells are exposed to high temperatures or an environment that is more or less acidic than normal, they cease to function
The enzyme permanently changes the 3D shape of their active site na dig can no longer bind it substrate.
Proteins in enzyme have denatured

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Optimum temperature

Temperature that the enzyme shows maximum activity

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Enzyme activity at low temperatures

Rate of enzyme reaction is very slow
Molecules have low kinetic energy and collisions are less frequent
Rate at which products form is very slow

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Optimum pH

PH at which the enzyme shows maximum activity

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Substrate concentration graph

As substrate concentration increases, so does the rate of reaction because more substrate are available to bind to the active site of the enzyme
At a certain point, rate of reaction plateaus, saturation has been reached, all enzymes are occupies (saturation point)

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Enzyme concentration graph

As enzyme concentration increases rate of reaction increases until it reaches a plateau state because there are increasingly more enzymes to bind with the substrate and all substrate has been converted to product

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Photosynthetic autotroph

Rely on sunlight energy to build complex organic molecules such as glucose from simple inorganic molecules such as CO2
Plants and algae

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Chemosynthetic autotrophs

Rely on chemical energy from the oxidation of reduced inorganic chemicals present in their environment
Some bacteria and archaea

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Heterotrophs

Feed on organic molecules made by chemosynthetic microbes and attain preformed organic molecules through feeding
Fungi, animals, some bacteria

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Photosynthesis

Process in which light energy is transformed into chemical energy in organic compounds in autotrophs
Takes place in chloroplasts which have chlorophyll and the enzymes required for photosynthesis

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Photosynthesis word equation

Carbon dioxide + water -> (light energy, chlorophyll) glucose + oxygen

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Photosynthesis chemical equation

6CO2+ 12H2O -> (light energy, chlorophyll) C6H12O6 + 6O2 + 6H2O

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Chloroplasts

In mesophyll cells, in the leaves of plants
Double membrane, storms, thylakoids membrane, granum

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Chlorophyll

Chlorophyll a and b use red and blue light for photosynthesis
Other accessory pigments absorb light energy of different colours and pass this energy to the chlorophyll for photosynthesis

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Results of photosynthesis

Oxygen produced is returned to atmosphere or used by cell in cellular respiration
Results in a gain of weight due to the glucose that is produced, which is converted to starch and stored
Other organic compounds can be produced from glucose if required by the plant

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Chemosynthesis

Process of using energy released from the oxidation of inorganic molecules to build organic molecules from carbon dioxide
Carried out by organisms in environments lacking sunlight

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ATP

Adenosine tri phosphate
Primary energy source for the cell
Formed when energy is released during cellular respiration of glucose
Used for active transport, muscle contractions, manufacturing chemicals, structure production etc.
Glucose is 60% heat energy, 40% atp

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Cellular respiration

Process in which all living cells breaks down organic molecules to obtain energy in the form of atp to carry out their necessary activities,
Chemical energy in glucose is transferred into chemical energy in atp

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Aerobic respiration word equation

Glucose + oxygen -> (36ADP+36Pi->36ATP) carbon dioxide+water+heat energy

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Aerobic respiration chemical equation

C6H12O6+6O2-> (36ADP+36Pi->36ATP) 6CO2+6H2O+ heat energy

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Step 1 aerobic respiration

Glycolysis
Cytosol
Glucose is broken down into pyruvate and energy released is used to make 2ATP molecules

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Step 2 aerobic respiration

Kreb's cycle
Matrix of mitochondria
Puruvate is further broken down to produce CO2 and 2 ATP molecules

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Step 3 aerobic respiration
Inner membrane of mitochondria
Further reactions take place using electron acceptors where O2 is the final electron acceptor and a further 32ATP molecule are made

Electron transport chain

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Anaerobic respiration in animal cells

Glucose -> (2ADP+2Pi->2ATP) lactic acid+ heat energy

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Anaerobic respiration in plants or fungal cells

Glucose-> (2ADP+2Pi->2ATP) ethanol+carbon dioxide+heat energy

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Results of cellular respiration

Overall loss of weight because glucose is broken down and H2O and CO2 are expelled

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Is aerobic better than anaerobic?

Yes-more efficient
In anaerobic, glucose is not fully broken down and only 2ATP is produced
Although very rapid production, it is sustained over a short time only