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B4- Bioenergetics Flashcards

1
Q

Where does photosynthesis take place in the plant cells?

A

Chloroplasts

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2
Q

Is photosynthesis endothermic or exothermic?

A

Endothermic

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3
Q

What is the SYMBOL equation for photosynthesis

A

6C02 +6H2O➜C6H12O6+6O2

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4
Q

What are the five ways plants use glucose?

A
  • For respiration
  • Making cellulose
  • Making amino acids
  • Stored as fats or oils
  • Stored as starch
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5
Q

What 3 things affect the rate of photosynthesis?

A
  • Light
  • Concentration of CO2
  • Temperature
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6
Q

Can chlorophyll be a limiting factor of photosynthesis and how?

A

Yes, the amount of chlorophyll in a plant can be affected by disease or environmental stress, such as a lack of nutrients. These factors can cause chloroplasts to become damaged or to not make enough chlorophyll. This means the rate of photosynthesis is reduced because they can’t absorb as much sunlight

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7
Q

Describe how light impacts the rate of photosynthesis?

A

As the light level is raised, the rate of photosynthesis increases steadily- but only to a certain point

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8
Q

Describe and explain how light impacts the rate of photosynthesis?

A

As the light level is raised, the rate of photosynthesis increases steadily- but only to a certain point. Beyond that, it won’t make a difference- as light intensity increases, the rate will no longer increase. this is because it’ll be either the temperature or the CO2 level which is now the limiting factor, not light

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9
Q

What temperature is too hot for enzymes?

A

45°C, it is rare for outdoors but can get to that in a greenhouse

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10
Q

How do greenhouses work?

A

They help trap the Sun’s heat, and make sure that the temperature doesn’t become a limiting factor

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11
Q

What is a disadvantage of a greenhouse?

A

Expensive

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12
Q

Define respiration.

A

The process of transferring energy from glucose, which goes on in every cell

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13
Q

Do all living things respire?

A

Yes

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14
Q

Is respiration endothermic or exothermic?

A

Exothermic

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15
Q

What are three examples of how organisms use the energy transferred from respiration?

A
  • To build up larger molecules( e.g proteins or amino acids)
  • In animals it helps the muscles to contract
  • In mammals and birds the energy is used to keep their body temperature steady
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16
Q

What are chemical reactions controlled by in cells?

A

Enzymes

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17
Q

Is starch a big molecule?

A

Yes

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18
Q

What is starch made from?

A

Small glucose molecules

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19
Q

What are lipid molecules made from?

A

1 molecule of glycerol and three fatty acids,which are made into proteins

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20
Q

When is glucose broken down?

A

Respiration

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21
Q

What is urea made from?

A

Broken down proteins

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22
Q

Define metabolism

A

The sum of all the reactions that happen in a cell or the body is called metabolism

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23
Q

Aerobic respiration doesn’t need much oxygen.TRUE/FALSE

A

False, it needs plenty of oxygen

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24
Q

Where does most of the reaction in aerobic respiration?

A

Mitochondria

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25
What is the symbol equation for aerobic respiration?
C6H1206+6O2 ⇢6C02+6H2O
26
When is anaerobic respiration used?
When there isn't enough oxygen
27
What's the word equation for anaerobic respiration fro animals?
Glucose ⇢ Lactic acid
28
What's the word equation for anaerobic respiration in plants and yeast?
Glucose ⇢ Ethanol Carbon Dioxide
29
What is anaerobic respiration called in yeast?
Fermentation
30
What is oxygen debt?
The amount of oxygen your body needs to react with the buildup of lactic acid and remove it form the cell
31
What is the name of a section of a chromosome that controls a characteristic?
gene(s)
32
Cell E in Figure 2 contains 8 chromosomes. box Cell E divides by mitosis. How many chromosomes will each new cell contain?
8
33
Protease is an enzyme. Protease breaks down protein. What is protein broken down into
amino acids
34
Why is protein needed by the body
any one from: • for growth • for repair / replacement (of cells / tissues / organs)
35
Which organ in the human digestive system produces protease
stomach
36
Describe how you would test a sample of food to show it contains protein. box Give the reason for any safety precautions you would take.
* grinding up the food * add Biuret reagent (allow CuSO4 and NaOH) to food (sample) * protein turns solution (from blue) to purple / lilac * wear goggles to protect eyes * clean up spills immediately * Biuret / NaOH is an irritant / corrosive / poisonous
37
What is the platelet's function
Helps the blood to clot
38
Suggest why blood flow through the coronary arteries is lower in people with coronary heart disease
(because coronary) arteries / | they are narrower
39
Earthworms have a large surface area to volume ratio. | Suggest why a large surface area to volume ratio is an advantage to an earthworm.
(earthworm) can absorb more oxygen (in a given time) or increases / more gas exchange
40
What is photosynthesis
The process by which plants synthesise glucose using light energy from the Sun. Light energy is converted into chemical energy.
41
Where does photosynthesis take place?
Within chloroplasts in leaf palisade cells. They contain chlorophyll, a pigment which absorbs light energy.
42
State the equations for photosynthesis (word and symbol)
Word: carbon dioxide + water → glucose + oxygen Symbol: 6CO2 + 6H2O → C6H12O6+ 6O2
43
Is photosynthesis an endothermic or | exothermic reaction, and why
Endothermic - energy is transferred from | the environment to chloroplasts by light
44
How can you show that a plant gives off oxygen | during photosynthesis?
Using a water plant (eg. Elodea), collect gas bubbles produced during photosynthesis. The gas will relight a glowing splint as it contains oxygen.
45
Give examples of leaf adaptations which | maximise the rate of photosynthesis
● Broad leaves - maximise surface area. ● Thin leaves - short diffusion distance. ● Chlorophyll present - trap light energy. ● Veins - transport water to leaves via xylem, remove photosynthesis products via phloem. ● Air spaces - allow CO2 to enter and O2 to leave. ● Guard cells - control opening of stomata for gaseous exchange and prevent water loss.
46
What are the four main factors that affect the rate | of photosynthesis
● Temperature ● Light intensity ● Carbon dioxide concentration ● Amount of chlorophyll
47
How does temperature affect the rate of | photosynthesis?
Increasing the temperature increases the rate of photosynthesis as the kinetic energy of particles is increased. The rate decreases past a certain temperature as enzymes become denatured
48
How does light intensity affect the rate of | photosynthesis?
Increasing the light intensity increases the rate of photosynthesis until another factor becomes limiting
49
How does carbon dioxide concentration affect | the rate of photosynthesis
Increasing the carbon dioxide concentration increases the rate of photosynthesis (until another factor becomes limiting) as CO2 is required to make glucose.
50
How does the amount of chlorophyll affect the | rate of photosynthesis?
Decreasing the amount of chlorophyll (eg. due to a lack of magnesium) decreases the rate of photosynthesis as chlorophyll is required to absorb light energy
51
What is a limiting factor
An environmental factor which can restrict the rate of photosynthesis eg. light intensity
52
Explain how you can calculate the rate of | photosynthesis by measuring oxygen production
● Set up bubble potometer apparatus (pondweed in a sealed tube of water, attached to a capillary tube and a gas syringe). ● Oxygen gas produced causes the bubble in the capillary tube to move. The distance moved by the bubble is used to calculate the volume of oxygen produced
53
How can farmers use their knowledge of | limiting factors to increase their profits?
They can control temperature, light intensity and CO2 concentration to achieve the fastest possible rate of photosynthesis, leading to a greater yield
54
State the law which describes the relationship between the distance of a light source from a plant and light intensity
Inverse square law - light intensity∝1 / | distance2
55
State 5 uses of the glucose produced | during photosynthesis
``` ● Respiration ● Starch for storage ● Cellulose for strength ● Amino acid and protein synthesis (combined with nitrates) ● Lipids for energy storage in seeds ```
56
What is aerobic respiration
An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells
57
What are the equations for aerobic respiration? | word and symbol
Glucose + oxygen → carbon dioxide + water (+energy) | C6H12O2 + 6O2 → 6CO2 + 6H2O (+energy)
58
Where does aerobic respiration take place
In the mitochondria
59
Why do organisms require the energy | released by respiration?
● Synthesis of larger molecules ● Muscle contraction ● Maintenance of body temperature ● Active transport
60
What is anaerobic respiration
An exothermic reaction in which glucose is broken down to release energy in the absence of oxygen
61
What is the equation for anaerobic respiration
Glucose → lactic acid (+energy)
62
Why is anaerobic respiration less efficient than | aerobic respiration
Glucose is not completely broken down, | so less energy is transferred.
63
Why can anaerobic respiration lead to muscle | fatigue
Lactic acid (product of anaerobic respiration) builds up in muscles, preventing efficient contraction
64
What is an oxygen debt
The amount of oxygen needed to convert lactic acid into back into glucose after anaerobic respiration
65
What is fermentation
A type of anaerobic respiration that | occurs in yeast cells
66
What is the equation for fermentation?
Glucose → ethanol + carbon dioxide (+energy)
67
Why is the fermentation reaction important?
It is used in the production of bread and | alcoholic drinks
68
What are the differences between aerobic and | anaerobic respiration
● Aerobic requires oxygen; anaerobic does not. ● Aerobic produces CO2 and water; anaerobic produces lactic acid or ethanol + CO2. ● Aerobic transfers a greater amount of energy
69
How do muscles store glucose
As glycogen
70
What changes take place when muscular activity | increases in the body
● Heart rate increases and arteries dilate - increases flow of oxygenated blood to muscles. ● Breathing rate increases and breathing is deeper - increases the rate of gaseous exchange. ● Stored glycogen is converted back into glucose.
71
How is lactic acid transported away from the | muscles
Blood flow through the muscles transports lactic acid to the liver, where it is oxidised back to glucose
72
What is metabolism
The sum of all the reactions that take | place in a cell or an organism
73
How do cells use the energy transferred by | respiration
To continuously carry out enzyme-controlled processes which lead to the synthesis of new molecules.
74
Give examples of metabolic reactions
``` ● 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 ```

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