Flashcards in Photosynthesis & Respiration Deck (60)
Why do plants need energy?
-active transport (to take in minerals via their roots)
Why do animals need energy?
-maintenance of body temp
What is the purpose of photosynthesis?
light energy is used to make glucose from H2O and CO2 (light energy is converted to chemical energy in the form of glucose)
What is the overall equation for photosynthesis?
6CO2 + 6H2O + energy --> C6H12O6 + 6O2
How do animals obtain glucose?
by eating plants or other animals, then respire the glucose to release energy
How do animal and plant cells release energy?
cells release energy from glucose by respiration
What are the two types of respiration?
aerobic : respiration using O2
anaerobic : respiration without O2
What is the overall equation for aerobic respiration?
C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
In plants and yeast, what does anaerobic respiration produce?
ethanol and carbon dioxide and releases energy
In humans, what does anaerobic respiration produce?
lactate and releases energy
Why is ATP a good energy source?
-stores or releases a small, manageable amount of energy at a time, so no energy is wasted as heat
-small, soluble molecule so easily transported around cell
-easily broken down so energy released instantaneously
-can make other molecules more reactive by transferring one of its phosphate groups to them (phosphorylation)
-can't pass out of cell so cell always has an immediate supply of energy
Define metabolic pathway.
a series of small reactions controlled by enzymes e.g. respiration and photosynthesis
adding phosphate to a molecule
adding phosphate to a molecule using light
splitting of a molecule using light energy
when light energy 'excites' electrons in an atom or molecule, giving them more energy and causing them to be released. The release of electrons causes the atom or molecule to become a positively-charged ion
splitting of a molecule using water
removal of carbon dioxide from a molecule
removal of hydrogen from a molecule
What is a redox reaction?
reaction involving oxidation and reduction
What is a coenzyme?
a molecule that aids the function of an enzyme
How do coenzymes work?
by transferring a chemical group from one molecule to another
What is the coenzyme used in photosynthesis?
NADP transfers hydrogen from one molecule to another - it can reduce or oxidise a molecule
What are the enzymes used in respiration?
NAD and FAD transfer hydrogen from one molecule to another - they can reduce or oxidise a molecule.
Coenzyme A transfers acetate between molecules
Describe how the synthesis and breakdown of ATP meets the energy needs of a cell.
In the cell, ATP is synthesised from ADP and inorganic phosphate using energy from an energy-releasing reaction, e.g. respiration. The energy is stored as chemical energy in the phosphate bond. ATP synthase catalyses this reaction. ATP diffuses to the part of the cell that needs energy. Here, its broken down back into ADP and inorganic phosphate, which is catalysed by ATP hydrolase. Chemical energy is released from the phosphate bond and used by the cell.
Where does photosynthesis take place?
in chloroplasts of plant cells
What is the structure of a chloroplast?
-flattened organelle surrounded by a double membrane
-thylakoids are stacked up into grana, grana are linked by bits of thylakoid membrane called lamellae
-contain photosynthetic pigments (chlorophyll a, chlorophyll b, carotene)
What are photosynthetic pigments?
coloured substances that absorb light energy needed for photosynthesis (in thylakoid membranes, attached to proteins)
What is a photosystem?
protein and pigment