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Stage 2 Biology > 2.3 - Energy Transformations > Flashcards

2.3 - Energy Transformations Flashcards

1
Q

What is Energy?

A
  • Energy is the ability to do work, or produce a change. All cells require inputs of suitable forms of energy. This includes light energy for plant cells that contain chlorophyll, or chemical energy stored in complex molecules for animal cells.
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2
Q

What is Energy used for?

A
  • Energy obtained by cells is used for processes such as movement, synthesis of materials and helps cells maintain a stable internal environment.
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3
Q

Can Energy be created or destroyed?

A

No, energy cannot be created or destroyed, it can only be transformed.
- Energy transformation or conversions occur with cells. eg. light energy into chemical energy in cell performing photosynthesis.

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4
Q

Does life require energy?

A

Yes, all life requires a continued input of energy to maintain cell (and therefore) life processes = life stops without the continued input of energy.

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5
Q

What are the forms of energy?

A
  • Chemical energy
  • Radiant (light) energy
  • Heat (thermal) energy
  • Kinetic
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6
Q

What is Chemical energy?

A
  • This is the energy stored in the chemical bonds of complex molecules. Typically, carbohydrates and lipids in particular which contain usable amounts of energy for cells.
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7
Q

What is Radiant (light) energy?

A
  • Light energy is a form of radiant energy that is radiated from the sun and transformed into chemical energy during photosynthesis. Some of this is transferred to the all animals via feeding relationships.
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8
Q

What is Heat (thermal) energy?

A
  • This is the energy that is caused by the movements of atoms or molecules in a substance. Heat energy increases as atoms vibrate faster or molecules move faster; this has implications for all metabolic reactions.
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9
Q

What is Kinetic energy?

A
  • This is the energy associated with the movement of molecules, cell components or whole objects; including organisms. Energy may be required to move molecules, for example, in specific directions eg. Into a cell or to move chromosomes during cell division.
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10
Q

What organic molecules do organisms require in order to survive and carry out daily processes and activities?

A
  • Carbohydrates, lipids, proteins, and nucleic acids
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11
Q

What are Autotrophs?

A
  • Autotrophs are organisms that produce their own energy rich compounds from inorganic materials.
  • Transforms chemical energy for use through aerobic respiration.
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12
Q

What are Photosynthetic Autotrophs?

A
  • Photosynthetic Autotrophs use energy from the sunlight to carry out photosynthesis to produce a chemical store of energy. Most autotrophs are photosynthetic autotrophs.
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13
Q

what are Chemosynthetic Autotrophs?

A
  • Chemosynthetic Autotrophs oxidise chemical to obtain a chemical store of energy.
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14
Q

What are Heterotrophs?

A
  • Heterotrophs need to consume other organisms to obtain their supply of organic molecules as they are unable to manufacture these from raw inorganic materials.
  • In a food chain, heterotrophs feed on other heterotrophs or on autotrophs (producers)
  • Ultimately all heterotrophs rely on autotrophs for the supply of energy rich compounds. Therefore photosynthesis is important for life on earth.
  • Transforms chemical energy for use through aerobic respiration.
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15
Q

What is Photosynthesis?

A
  • The light energy that falls on and is absorbed by cells in the leaves of plant enables the process of photosynthesis to occur.
  • Photosynthesis is the process where, light energy is trapped by the green pigment of chlorophyll and this enables light energy to be transformed into chemical energy which is stored in the chemical bonds of organic molecules like glucose and starch.
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16
Q

What are Chloroplasts?

A
  • Chloroplasts are the membrane-bound organelles which are the site of photosynthesis.
  • They are abundant in the mesophyll tissue of leaves, arranged in layers in order to maximise their exposure to light energy that passes through the upper surface of the leaf.
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17
Q

What are Guard Cells?

A
  • Guard cells regulate the opening and closing of the stomates, and they are clearly visible in the lower epidermis.
  • When stomate are open, gas exchange, essential for the process of photosynthesis to occur.
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18
Q

What is the Chemical Equation for Photosynthesis?

A

6CO2 + 6H2O ———Sunlight + Chlorophyll- ———> C6H12O6 + 6O2

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19
Q

What is the Word Equation for Photosynthesis?

A

carbon dioxide + water ——sunlight + chlorophyll ————–> glucose (sugar) + oxygen

20
Q

What are the Factors that affect the rate of photosynthesis?

A
  • Wavelength of Light (colour)
  • Temperature
  • Light Intensity
  • CO2
  • Water Availability
21
Q

How does light affect the rate of photosynthesis?

A
  • Light is the source of energy input for the process of photosynthesis. Consequently, at low levels of light intenisty there will also be a low rate of photosynthesis, and as the light intensity increases so will the rate of photosynthesis increase.
22
Q

How does CO2 affect the rate of photosynthesis?

A
  • Based on the assumption that the stomates in the lower epidermis are open, permitting the diffusion of carbon dioxide into the leaf and thus the cells in the mesophyll. It can clearly be seen that the rate of photosynthesis increases as the concentration of carbon dioxide increases.
23
Q

What is energy transformations?

A

The ability to utilise energy is one of the characteristics of life. Cellular activities require energy and therefore energy transformations occur in cells to produce the necessary energy.

24
Q

What four cellular activities require energy transformation to occur?

A
  • Growth
  • Movement
  • Repair
  • Reproduction
25
Q

How is growth a cellular activity?

A

Growth – the uptake of the essential requirements and synthesis of proteins, nucleic acids, lipids and carbohydrates and the division and growth of cells.

26
Q

How is movement a cellular activity?

A

Movement – of organisms generally requires contraction of muscle cells. Movement in an organism can occur at the molecular, organelle, cellular and tissue level and require energy.

27
Q

How is repair a cellular activity?

A

Repair – e.g. red blood cells need to be continually make in humans, tissue which have been damaged need to be repaired and skin cells are continually replaced.

28
Q

How is restoration a cellular activity?

A

Reproduction – production of gametes, courting rituals and nurturing requires energy. Also flower production and storage of food requires energy.

29
Q

What is Aerobic Respiration?

A

Aerobic Respiration is the metabolic process of most living things in which food molecules or glucose are turned into usable energy for the cell, called ATP.
- 36 ATP molecules are produced

30
Q

How is Aerobic Respiration produced?

A
  • Aerobic Respiration is the most efficient way of producing energy, through many small steps which are regulated by enzymes.
  • The reaction rate of this can therefore be easily controlled.
31
Q

What is the Word Equation for Aerobic Respiration?

A

glucose + oxygen ———> carbon dioxide + water + energy

32
Q

What is the Chemical Equation for Aerobic Respiration?

A

C6H12O6 + O2 ——–> CO2 + H2O + energy

33
Q

Where does energy come from?

A
  • Energy comes from the breakdown of the energy rich compound glucose
  • Energy which is not lost as heat is used to make ATP
  • A maximum of 36 ATP molecules can be produced
34
Q

What are the two steps in the Krebs cycle?

A

Step 1:
○ Glycolysis (in the cytoplasm)
▪ Glycolysis is the first stage of aerobic respiration and takes place in the cytosol.
○ Glucose > pyruvate

Step 2:
○ Krebs (in the mitochondrion)
▪ The last two stages occur in the membrane-bound organelle called the mitochondrion.
○ Pyruvate (and oxygen) gets broken down into carbon dioxide + water + ALOT MORE ENERGY (most of the energy is released)

35
Q

How many molecules of ATP does aerobic respiration produce?

A
  • Aerobic respiration produces 36 molecules of ATP, uses 2. Net production of 34 molecules of ATP.
36
Q

What is Fermentation? (anaerobic respiration)

A

• Fermentation is the process of respiration in the absence of oxygen
○ Is a multi-step process, involves many enzymes
○ Glucose is used, but is not completely broken down therefore releasing less ATP molecules than aerobic respiration
○ Only 2 ATP molecules are produced
○ Mitochondria are not involved
○ Oxygen is not consumed
○ Products obtain from fermentation depend on organisms involved

37
Q

What are the products obtained from fermentation?

A

• The products obtained from fermentation depend on the type of cell:

  - Plant and Yeast Cells – produce ethanol and carbon dioxide (called alcoholic fermentation)
  - Animal Cells – produce lactic acid (called lactic acid fermentation/anaerobic respiration)
38
Q

What is the Word Equation for fermentation in PLANT Cells?

A

glucose ———> ethanol + carbon dioxide + energy

39
Q

What is the Chemical Equation for fermentation in PLANT Cells?

A

C6H12O6 ——–> 2C2H5OH + 2CO2 + energy

40
Q

What is the Word Equation for fermentation in ANIMAL Cells?

A

glucose ———> lactic acid + energy

41
Q

What is the Chemical Equation for fermentation in ANIMAL Cells?

A

C6H12O6 ———->2C3H6O3 + energy

42
Q

What is Chemical Energy?

A

• Chemical energy is a form of potential energy that is available to cells to do work
• This energy is stored in the bonds between atoms in molecules
○ Bigger molecules have more atoms and more bonds
▪ Therefore, they store more energy in their chemical bonds

• When complex molecules break down to smaller molecules there is a release of this chemical energy.

43
Q

What is Glucose?

A

• Glucose is a molecule that is high in chemical energy that can be released via the process of respiration.
- Approximately 40% of the energy from the glucose molecules is transferred into ATP molecules.
• 60% of the energy in the glucose molecules is lost as free energy or heat.
• When big ‘energy rich’ molecules are changed into smaller ‘energy poor’ molecules some of the energy is stored in other molecules and the rest is released as heat.

44
Q

What is ATP?

A
  • ATP is the cell’s immediate source of energy and is used for almost every energy requiring reaction that occurs in cells.
  • ATP is made and used continuously (ATP/ADP cycle)
45
Q

What is ATP made up of?

A

○ ATP is made up of three parts:

- An adenine base
- A 5 carbon sugar (Ribose)
    - Three phosphate groups linked together
46
Q

How is ATP broken down?

A

• ATP can be broken down to form Adenosine Di-Phosphate (ADP) and an inorganic phosphate - the bond between the second and third phosphate molecules is very weak.
- When ATP is broken down to ADP energy becomes available for use in the cell.

Stage 2 Biology (8 decks)

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