bioenergetics Flashcards
Plant cells contain chloroplasts which contain _________. Chlorophyll is a _______ that can absorb light energy.
Plant cells contain chloroplasts which contain chlorophyll. Chlorophyll is a pigment that can absorb light energy.
endothermic reactions require _______
energy
Photosynthesis takes place inside chloroplasts found in plants and algae. The reaction is __________, meaning that it requires energy. The source of this energy is sunlight, which is ________ by a chemical called chlorophyll inside chloroplasts in plant cells.
Photosynthesis takes place inside chloroplasts found in plants and algae. The reaction is endothermic, meaning that it requires energy. The source of this energy is sunlight, which is trapped by a chemical called chlorophyll inside chloroplasts in plant cells.
Factors affecting the rate of photosynthesis:
CO2 and chlorophyll concentration
light intensity
temp
Factors affecting the rate of photosynthesis: temperature
Increasing the temperature increases the rate of photosynthesis because more energy is provided.
However, if the temperature is increased to above about 45°C, the enzymes that catalyse (speed-up) the reaction begin to denature (not work anymore).
This causes the rate of the reaction to drop sharply until it stops altogether.
Factors affecting the rate of photosynthesis: carbon dioxide concentration
Carbon dioxide concentration
Increasing the carbon dioxide concentration increases the rate of photosynthesis because carbon dioxide is a reactant in photosynthesis.
However, above a certain threshold, further increases in the carbon dioxide concentration do not increase the rate of photosynthesis because another factor (such as light intensity) is limiting the rate of reaction.
Factors affecting the rate of photosynthesis: Light intensity
Increasing light intensity increases the rate of photosynthesis because more energy is provided.
However, if the light intensity is increased above a certain threshold, the rate of photosynthesis will not increase because another factor (such as temperature) is limiting the rate of the reaction.
Balance the following photosynthesis question:
_CO2 + _H2O –> C6H12O6 + _O2
Balance the following photosynthesis question:
6CO2 + 6H2O –> C6H12O6 + 6O2
In plants, glucose from photosynthesis can be converted into:
In plants, glucose from photosynthesis can be converted into:
Starch
Cellulose
Fats
Proteins
CO2 concentration, light levels and temperature are all at optimum values. What might be the limiting factor of rate of photosynthesis, and why?
CO2 concentration, light levels and temperature are all at optimum values. What might be the limiting factor of rate of photosynthesis, and why?
The concentration of mineral ions in the soil is probably the limiting factor.
Chlorophyll absorbs light energy and the production of chlorophyll requires these mineral ions (especially Mg2+).
Identify the products of glucose in plants: Starch
Identify the products of glucose in plants:
Starch
Insoluble, stored in stems, leaves or roots.
Identify the products of glucose in plants:
Proteins
Identify the products of glucose in plants:
Proteins
Required for cell growth, repair, and enzymes.
A source of nitrogen is also needed for glucose to be converted into proteins.
Plants get this nitrogen by absorbing nitrate ions (minerals) from soil.
Identify the products of glucose in plants:
Fats
Identify the products of glucose in plants:
Fats
Stored in structures such as seeds. For example, sunflower seeds are a key ingredient in cooking oils.
Identify the products of glucose in plants:
Cellulose
Identify the products of glucose in plants:
Cellulose
Particularly important for fast-growing plants, is used to strengthen cell walls.
To investigate the effect of light intensity on the rate of photosynthesis I would:
use an aquatic plant(lives under water) like pondweed
count number of bubbles plant produces
change the distance between lamp and pondweed
What is the light intensity when a lamp is placed 5cm away from a plant?
What is the light intensity when a lamp is placed 5cm away from a plant?
1 Remember the equation for light intensity Light intensity (L) = 1 ÷ distance2 2 Substitute in the values L = 1 ÷ 52 3 Work out the squared value L = 1 ÷ 25 4 Write the answer L = 1/25
equation for light intensity
equation for light intensity Light intensity (L) = 1 ÷ distance2
In an experiment using pondweed to investigate the effect of light intensity on the rate of photosynthesis, the light intensity is the __________ variable and the number of bubbles is the ________ variable.
In an experiment using pondweed to investigate the effect of light intensity on the rate of photosynthesis, the light intensity is the independent variable and the number of bubbles is the dependent variable.
A variable is …
A variable is something you are trying to measure
a dependent variable is ….
a dependent variable is exactly what it sounds like. It is something that depends on other factors.
An independent variable is ….
An independent variable is exactly what it sounds like. It is a variable that stands alone and isn’t changed by the other variables you are trying to measure.
For example, someone’s age might be an independent variable.
Organisms need to make __________ from ___________. Proteins can be made from __________. These are built from sugars and other nutrients in plants.
Organisms need energy to make large molecules from smaller molecules. Proteins can be made from amino acids. These are built from sugars and other nutrients in plants.
what molecules can be joined together to produce starch?
glucose
Organisms needs energy for:
homeostasis
muscle contraction
growth
