M.1.2 Flashcards
Photosynthesis and Cellular Respiration
1
Q
Carbon fixation
A
- Changing of inorganic carbon molecule into organic sugars that combine to form glucose
2
Q
Inorganic molecule
A
- Not produced by an organism
- Occurs readily in nature, e.g. carbon dioxide, water, oxygen, mineral salts
3
Q
Organic molecule
A
- Chemicals produced by an organism
- e.g., lipids, proteins, carbohydrates, nucleic acid
4
Q
Heterotrophs
A
- Organisms that can’t make organic material
- Consumes organic material for energy
5
Q
Chloroplast
A
- Disc shaped organelle
- contains stacks of thylakoid (grana)
6
Q
Mesophyll
A
- Green tissue of the cell, where chloroplasts are located
7
Q
Stoma(ta)
A
- Pores in the leaf that allows carbon dioxide to enter and oxygen to leave
- Opened/closed by guard cells on either side of it
8
Q
Photosynthesis basic formula
A
Water + Carbon Dioxide → (in presence of sunlight through a chloroplast) Glucose + Oxygen Gas
H20 + CO2 (with sunlight) → C6H12O6 + O2
9
Q
Light reaction
A
- 1st stage of photosynthesis
- Generates energy (ATP, NADPH) needed for dark reaction, oxygen and hydrogen by splitting water
- Chlorophyll absorbs light energy, splits water to produce H+ ions
- Oxygen released as a byproduct
- Occurs in thylakoid membrane’s photosystem
10
Q
Calvin Cycle overview
A
- 2nd stage of photosynthesis
- Produces glucose from CO2 using the ATP + NADPH energy from the light cycle
- RuBP combines with CO2 to form G3P. One G3P is converted into glucose, the rest is converted back into RuBP for the next cycle
11
Q
Chlorophyll
A
- Pigment that traps light energy
- Chlorophyll A: blue-violet and red wavelengths
- Chlorophyll B: blue and orange wavelengths, reflects yellow-green wavelengths
- Doesn’t capture green wavelengths
12
Q
Obligate anaerobes
A
- Die if exposed to oxygen, as they don’t produce enzymes necessary to detoxify reactive oxygen species.
e.g. bacteroides (obligate anaerobic bacteria)
13
Q
Facultative anaerobes
A
- Can live with or without oxygen, as it produces ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent.
e.g. e. coli and yeast
14
Q
Guard cells
A
- Cells surrounding the stomata, changing the size of pores by turgor pressure (due to the large vacuole in guard cells)
Turgid: fills with water, stretching the guard cells to curve outwards, causing it to open
Flaccid: as water leaves the vacuole, the guard cells deflate, collapsing inwards and closing the stomata. - If the environment is hot and dry, this causes a steeper concentration gradient for water vapour to diffuse out of the leaf. This loss of water in the guard cells cause them to become flaccid and close the stomata. This reduces further water loss.
15
Q
Enzymes
A
- special proteins: biological catalysts (in this case) that speeds up photosynthesis