B4 - Bioenergetics Flashcards
What is the primary outcome of photosynthesis?
Glucose and oxygen
Photosynthesis transforms carbon dioxide and water into glucose and oxygen using light energy.
Where does photosynthesis take place in plant cells?
Chloroplasts
Chloroplasts contain pigments like chlorophyll that absorb light energy.
What type of reaction is photosynthesis?
Endothermic
This means energy is absorbed from the environment during the process.
Fill in the blank: The word equation for photosynthesis is _______.
carbon dioxide + water → glucose + oxygen
What is the symbol equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
This represents the chemical transformation during photosynthesis.
List the five main uses of glucose in plants.
- For respiration
- Making cellulose
- Making amino acids
- Stored as oils or fats
- Stored as starch
How does glucose help in respiration?
Transfers energy
This energy enables plants to convert glucose into other useful substances.
What is the role of glucose in making cellulose?
Converted into cellulose for strong plant cell walls
How are amino acids produced in plants?
By combining glucose with nitrate ions
Nitrate ions are absorbed from the soil.
What is stored as oils or fats in plants?
Glucose
Glucose is converted into lipids for storage in seeds.
Why is starch better for storage than glucose?
Starch is insoluble
This prevents cells from drawing in excess water and swelling.
What factors affect the rate of photosynthesis?
- Intensity of light
- Concentration of CO₂
- Temperature
What does it mean if a factor is a limiting factor in photosynthesis?
It stops photosynthesis from happening any faster.
Which factor is typically limiting at night?
Light
Which factor is often limiting in winter?
Temperature
What can also be a limiting factor of photosynthesis?
Chlorophyll
The amount of chlorophyll can be affected by disease or environmental stress.
How can environmental stress affect chlorophyll?
Causes chloroplasts to become damaged or insufficiently produce chlorophyll
What happens if chlorophyll is not sufficient in a plant?
The rate of photosynthesis is reduced
This occurs because the plant cannot absorb enough light.
What is the primary outcome of photosynthesis?
Glucose and oxygen
Photosynthesis transforms carbon dioxide and water into glucose and oxygen using light energy.
Where does photosynthesis take place in plant cells?
Chloroplasts
Chloroplasts contain pigments like chlorophyll that absorb light energy.
What type of reaction is photosynthesis?
Endothermic
This means energy is absorbed from the environment during the process.
Fill in the blank: The word equation for photosynthesis is _______.
carbon dioxide + water → glucose + oxygen
What is the symbol equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
This represents the chemical transformation during photosynthesis.
List the five main uses of glucose in plants.
- For respiration
- Making cellulose
- Making amino acids
- Stored as oils or fats
- Stored as starch
How does glucose help in respiration?
Transfers energy
This energy enables plants to convert glucose into other useful substances.
What is the role of glucose in making cellulose?
Converted into cellulose for strong plant cell walls
How are amino acids produced in plants?
By combining glucose with nitrate ions
Nitrate ions are absorbed from the soil.
What is stored as oils or fats in plants?
Glucose
Glucose is converted into lipids for storage in seeds.
Why is starch better for storage than glucose?
Starch is insoluble
This prevents cells from drawing in excess water and swelling.
What factors affect the rate of photosynthesis?
- Intensity of light
- Concentration of CO₂
- Temperature
What does it mean if a factor is a limiting factor in photosynthesis?
It stops photosynthesis from happening any faster.
Which factor is typically limiting at night?
Light
Which factor is often limiting in winter?
Temperature
What can also be a limiting factor of photosynthesis?
Chlorophyll
The amount of chlorophyll can be affected by disease or environmental stress.
How can environmental stress affect chlorophyll?
Causes chloroplasts to become damaged or insufficiently produce chlorophyll
What happens if chlorophyll is not sufficient in a plant?
The rate of photosynthesis is reduced
This occurs because the plant cannot absorb enough light.
What is the effect of light intensity on the rate of photosynthesis?
As light intensity increases, the rate of photosynthesis increases steadily until it levels off when light is no longer the limiting factor.
At what temperature does the rate of photosynthesis level off at a higher point?
At 25 °C.
What does it indicate when the line levels off at a higher point at 25 °C compared to 15 °C?
Temperature must have been a limiting factor at 15 °C.
How does CO₂ concentration affect the rate of photosynthesis?
Both lines level off when light is no longer the limiting factor, and the line at a higher CO₂ concentration levels off at a higher point.
What CO₂ concentrations are compared in the text?
- 0.4% CO₂
- 0.04% CO₂
What does it mean if the line at 0.4% CO₂ levels off at a higher point than at 0.04%?
CO₂ concentration must have been a limiting factor at 0.04% CO₂.
True or False: Temperature is the limiting factor when comparing the rates of photosynthesis at different CO₂ concentrations at the same temperature.
False.
What happens to light intensity as the distance from the light source increases?
Light intensity decreases as distance increases.
How is the relationship between distance and light intensity defined?
Distance and light intensity are inversely proportional.
What does the inverse square law state about light intensity?
Light intensity decreases in proportion to the square of the distance.
What is the formula representing the inverse square law?
light intensity ∝ 1/(distance)^2
If the distance is halved, how much does light intensity increase?
Light intensity becomes four times greater.
If the distance is tripled, how much does light intensity decrease?
Light intensity becomes nine times smaller.
What is the light intensity when the lamp is 10 cm from the pondweed?
Light intensity = 0.01 a.u.
What does ‘a.u.’ stand for in the context of light intensity?
‘a.u.’ stands for arbitrary units.
What is the most common way to artificially create the ideal environment for plants?
Growing plants in a greenhouse.
How do greenhouses help in plant growth?
They trap the Sun’s heat and maintain ideal temperature conditions.
What might a farmer use in winter to maintain temperature in a greenhouse?
A heater.
What methods can be used to cool down a greenhouse in summer?
Using shades and ventilation.
Why do commercial farmers supply artificial light?
To give plants more quality photosynthesis time after sunset.
How can carbon dioxide levels be increased in a greenhouse?
By using a paraffin heater that produces CO2 as a by-product.
What advantage does keeping plants in a greenhouse provide regarding pests?
It makes it easier to keep plants free from pests and diseases.
What additional resource can farmers add to the soil for plant growth?
Fertilizers.
What is the goal of providing ideal conditions for photosynthesis in farming?
To grow plants faster and harvest decent crops more often.
True or False: Providing more heat and light than plants need is beneficial for growth.
False.
What is respiration?
The process of transferring energy from the breakdown of glucose, occurring in every cell continuously.
True or False: Respiration is the same as breathing.
False
Where does respiration occur?
In every cell of the body and in plants.
What type of reaction is respiration?
Exothermic
List three uses of energy transferred by respiration.
- To build up larger molecules from smaller ones
- To allow muscles to contract in animals
- To maintain body temperature in mammals and birds
What is metabolism?
The sum of all the chemical reactions in an organism.
What role do enzymes play in metabolism?
They control the chemical reactions happening in a cell.
Fill in the blank: Enzymes are _______.
biological catalysts
What are two types of reactions that occur in metabolism?
- Building larger molecules from smaller ones
- Breaking down larger molecules into smaller ones
Provide an example of a molecule formed from smaller ones.
Starch, glycogen, cellulose, lipids, or proteins.
What happens to excess protein in the body?
It is broken down to produce urea, which is excreted in urine.
What is the total of all reactions in a cell called?
Metabolism
What are the two types of respiration?
Aerobic and Anaerobic Respiration
What is aerobic respiration?
Respiration using oxygen
Why is aerobic respiration considered the most efficient way to transfer energy from glucose?
It fully oxidizes glucose
Where do most reactions in aerobic respiration occur?
Inside mitochondria
What are the word and symbol equations for aerobic respiration?
glucose + oxygen → carbon dioxide + water
CH₂O + 6O₂ → 6CO₂ + 6H₂O
What happens during anaerobic respiration?
Incomplete breakdown of glucose without oxygen
What is the word equation for anaerobic respiration in muscle cells?
glucose → lactic acid
Does anaerobic respiration transfer as much energy as aerobic respiration?
No, it transfers much less energy
In what situations is anaerobic respiration useful?
In emergencies, e.g. during vigorous exercise
What do plants and yeast produce during anaerobic respiration?
Ethanol (alcohol) and carbon dioxide
What is the word equation for anaerobic respiration in plants and yeast cells?
glucose → ethanol + carbon dioxide
What is fermentation in yeast?
Anaerobic respiration in yeast cells
What is the significance of fermentation in the food and drinks industry?
Used to make bread and alcoholic drinks
What causes bread to rise during bread-making?
Carbon dioxide from fermentation
What is produced during the fermentation process in beer and wine-making?
Alcohol
What type of organisms are yeast?
Single-celled organisms
What is the primary energy source for muscle contraction during exercise?
Respiration
Muscles require energy from respiration to contract effectively.
How does the body increase oxygen intake during exercise?
Increased breathing rate and breath volume
This increase helps to get more oxygen into the blood.
What happens to heart rate during exercise?
Heart rate increases
This helps to circulate oxygenated blood around the body faster.
What occurs when the body cannot supply enough oxygen during vigorous exercise?
Muscles start respiring anaerobically
Anaerobic respiration leads to lactic acid build-up.
True or False: Anaerobic respiration is the most efficient way to transfer energy from glucose.
False
Anaerobic respiration produces lactic acid, which is less efficient.
What is lactic acid a product of?
Incomplete oxidation of glucose
Lactic acid can cause muscle pain and fatigue.
What is an ‘oxygen debt’?
The amount of extra oxygen needed to react with lactic acid
It helps to remove lactic acid from the cells.
Fill in the blank: After exercising, you need to repay the oxygen that you didn’t get to your muscles in time because your lungs, heart, and blood couldn’t keep up with the _______.
Demand
How does the body cope with high levels of lactic acid?
Transporting lactic acid to the liver for conversion back to glucose
This process helps to manage lactic acid levels in the muscles.
What method can you use to measure breathing rate during exercise?
Counting breaths
This can be done before and after different levels of exercise.
What is the expected trend in pulse rate with increasing exercise intensity?
Pulse rate increases
Higher intensity requires more oxygen delivery to muscles.
What is a good practice to reduce random errors when measuring pulse rate in a group?
Plot the average pulse rate for each exercise
This helps to smooth out individual variations.
How can you find your pulse?
By putting two fingers on the inside of your wrist or neck
Count the number of pulses in one minute.
