bioenergetics Flashcards

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1
Q

what is photosynthesis?

A

The process by which plants synthesise glucose using light energy from the Sun.

Light energy is converted into chemical energy

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2
Q

where does photosynthesis take place?

A

Within chloroplast in leaf Palaside cells. They contain chlorophyll, a pigment which absorbs light energy.

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3
Q

State the equations for photosynthesis

A

6co2 + 6H2o —-> C6H12O6 + 6O2

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4
Q

Is photosynthesis an endothermic or exothermic reaction and why?

A

Endothermic energies transferred from the environment to the chloroplast by light

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5
Q

How can you show that a plant gives off oxygen during photosynthesis?

A

using a water plant, collect gas bubbles produced during photosynthesis. The gas will relight a glowing splint as it contains oxygen

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6
Q

Give examples of leaf adaptations which maximise the rate of photosynthesis

A

broadleaves – maximise surface area
Fin leaves – short diffusion distance
Chlorophyll present – trap light energy
Veins – transport water to leaves via xylem, remove photosynthesis products by phloem
airspaces– allows CO2 to enter an O2 to leave
Guard cells – control opening of stomata for gaseous exchange preventing water loss 

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7
Q

what are the four main factors that affect the rate of photosynthesis?

A

Temperature, light intensity, carbon dioxide concentration, amount of chlorophyll

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8
Q

how does the temperature affect the rate of photosynthesis?

A

Increasing the temperature increases the rate of photosynthesis as the kinetic energy of the particles is increased. The rate decreases past a certain temperature as enzymes become denatures.

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9
Q

how does light intensity affect the rate of photosynthesis?

A

Increasing the light intensity increases the rate of photosynthesis until another factor becomes limited

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10
Q

how does carbon dioxide concentration affect the rate of photosynthesis?

A

Increasing the carbon dioxide concentration increases the rate of photosynthesis ( until another factor becomes limiting ) as CO2 is required to make glucose

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11
Q

How does the amount of chlorophyll affect the rate of photosynthesis?

A

decreasing the amount of chlorophyll(eg due a to lack of magnesium) decreases the rate of photosynthesis as chlorophyll is required to absorb light energy

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12
Q

what is a limiting factor?

A

An environmental factor which can restrict the rate of photosynthesis
eg light intensity

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13
Q

explain how you can calculate the rate of photosynthesis by measuring oxygen production

A

set up a bubble potometer apparatus (pondweed in a sealed tube of water, attached to a capillary tube and a gas syringe )

Oxygen gas produced causes the bubbles in the capillary tube to move the distance moved by the bubble is used to calculate the volume of oxygen produced 

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14
Q

How can farmers use their knowledge of limiting factors to increase their profits?

A

They can control temperature, light intensity and CO2 concentration to achieve the fastest possible rate of photosynthesis, leading to greater yield

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15
Q

State the law which describes the relationship between the distance of light source from a plant and light intensity

A
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16
Q

State five uses of glucose produced during photosynthesis

A

Respiration
Starch for Storage
Cellulose for Strength
Amino acid and protein synthesis (combined with nitrates)
Lipids for energy storage and seeds

17
Q

What is aerobic respiration?

A

An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells

18
Q

what are the equations for aerobic respiration?

A

C6H12O6 + 6O2 ———> 6CO2 + 6H2O

19
Q

where does aerobic respiration take place?

A

Mitochondria

20
Q

Why do organisms require the energy release by respiration?

A

synthesis of larger molecules
Muscle contraction
Maintenance of body temperature
Active transport

21
Q

What is an anaerobic respiration?

A

An exothermic reaction in which glucose is broken down to release energy in the absence of oxygen

22
Q

what is the equation for anaerobic respiration?

A

glucose —-> lactic acid (+energy)

23
Q

Why is anaerobic respiration less efficient than aerobic respiration?

A

Glucose is not completely broken down, so less energy is transferred

24
Q

why can anaerobic respiration lead to muscle fatigue?

A

Lactic acid buildup in muscles, preventing efficient contraction

25
Q

What is an oxygen debt

A

The amount of oxygen needed to convert lactic acid into back into glucose after anaerobic respiration

26
Q

what is fermentation?

A

A type of anaerobic respiration that occurs in yeast cells

27
Q

what is the equation for fermentation?

A

glucose —-> ethanol + carbon dioxide (+energy)

28
Q

why is the fermentation reaction important?

A

It is used in the production of bread and alcoholic drinks

29
Q

What are the differences between aerobic and anaerobic respiration?

A

aerobic requires oxygen; anaerobic does not
Aerobic produces CO2 and water: anaerobic produces lactic acid or ethanol and CO2
Aerobic transfers, a greater amount of energy

30
Q

how do muscles store glucose?

A

As glycogen

31
Q

What changes take place when muscular activity increases in the body?

A

heart rate increases in arteries dilate – increases flow oxygenated blood to the muscles

Breathing rate increases and breathing is deeper – increases the rate of gaseous exchange

stores glycol is converted back into glucose

32
Q

How is lactic acid transported away from the muscles?

A

blood flow through the muscles transports lactic acid to the liver, where it is oxidised back to glucose

33
Q

What is metabolism?

A

The sum of all the reactions that take place in a cell or an organism

34
Q

How do cells use energy transferred by respiration?

A

To continuously carry out enzyme controlled processes which lead to the synthesis of new molecules

35
Q

give examples of metabolic reactions

A

Glucose into starch/glycogen/cellulose
Glycerol and fatty acids into lipids
Glucose and nitrate ions into amino acids
Photosynthesis
Respiration
Breakdown of excess proteins into urea