Bioenergetics (Seneca) Flashcards
Photosynthesis takes place inside …
chloroplasts found in plants and algae.
Photosynthesis takes place inside chloroplasts found in plants and algae. The reaction is ————-, meaning that it requires energy.
endothermic
Photosynthesis takes place inside chloroplasts found in plants and algae. The reaction is endothermic, meaning that it …
requires energy.
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 1. , which is 2.
- sunlight
- trapped by a chemical called chlorophyll inside chloroplasts in plant cells.
Photosynthesis converts ————-into oxygen and glucose. Sunlight provides the energy source for this process.
carbon dioxide and water
Photosynthesis converts carbon dioxide and water into ————-. Sunlight provides the energy source for this process.
oxygen and glucose
Photosynthesis converts carbon dioxide and water into oxygen and glucose. ———- provides the energy source for this process.
Sunlight
6CO2 + 6H2O —>
C6H12O6 +6O2
Increasing the carbon dioxide concentration ———— the rate of photosynthesis because carbon dioxide is a reactant in photosynthesis.
increases
Increasing the carbon dioxide concentration increases the rate of photosynthesis because …
carbon dioxide is a reactant in photosynthesis.
Increasing the carbon dioxide concentration increases the rate of photosynthesis because carbon dioxide is a reactant in photosynthesis.
But, above a certain threshold, further———————————— because another factor (such as light intensity) is limiting the rate of reaction.
increases in the carbon dioxide concentration do not increase the rate of photosynthesis
Increasing the carbon dioxide concentration increases the rate of photosynthesis because carbon dioxide is a reactant in photosynthesis.
But, 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.
High chlorophyll concentration gives a ——- rate of photosynthesis.
high
A greater light intensity means a ——— rate of photosynthesis. This is because more energy is being provided.
greater
A greater light intensity means a greater rate of photosynthesis. This is because …
more energy is being provided.
A greater light intensity means a greater rate of photosynthesis. This is because more energy is being provided.
But, 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.
Increasing the temperature ———- the rate of photosynthesis because more energy is provided.
increases
Increasing the temperature increases the rate of photosynthesis because …
more energy is provided
Increasing the temperature increases the rate of photosynthesis because more energy is provided.
But, if the temperature is …
increased to above about 45°C, the enzymes that catalyse (speed-up) the reaction begin to denature (not work anymore).
Increasing the temperature increases the rate of photosynthesis because more energy is provided.
But, 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:
- temperature
- light intensity
- carbon dioxide concentration
- chlorophyll
Initially, increasing carbon dioxide concentration increases the rate of photosynthesis.
Above a certain threshold, …
further increases in carbon dioxide concentration do not increase the rate of photosynthesis as it is no longer the limiting factor.
At night, ———— is usually the limiting factor.
light intensity
A limiting factor is …
a factor that restricts the rate of a reaction.
In warm and bright conditions, ——— concentration is usually the limiting factor.
carbon dioxide
If plants are grown in mineral-deficient (lacking minerals) soil, they may not absorb enough minerals to produce lots of chlorophyll.
In this case, ————- can be the limiting factor.
chlorophyll concentration
In winter, ———- is usually the limiting factor.
temperature
Lighting and heating in greenhouses ———- the rate of photosynthesis that is possible.
increase
A high rate of photosynthesis means that …
crops grow faster and the total yield is bigger.
Farmers must evaluate the trade-off between the costs of ————, and the rate of photosynthesis that is possible.
lighting and heating
Proteins are needed for …
cell growth and repair.
A source of ————- is also needed for glucose to be converted into proteins.
nitrogen
Plants get this nitrogen by …
absorbing nitrate ions (minerals) from soil.
Fats and oils are stored in …
structures such as seeds.
Cellulose is used to 1. It is particularly important for 2.
- strengthen cell walls
- fast-growing plants
Starch is 1. and is stored in 2.
- insoluble (cannot be dissolved)
- stems, leaves or roots
What products can glucose be converted into in plants?
- starch
- Cellulose
- Fats
- Proteins
Testing the Rate of Photosynthesis
You can easily investigate the effect of light intensity on the rate of photosynthesis by using an aquatic (lives in water) plant like pondweed.
To do this, change the distance between the lamp and the pondweed and count the number of bubbles produced per unit time (e.g. five per minute).
In this experiment, light intensity is the independent variable and the number of bubbles is the dependent variable.
light intensity=
1÷distance (squared)
If a lamp is moved closer to a plant:
- The plant’s rate of photosynthesis will likely increase
- The light intensity on the plant increases
The bubbles used to measure the rate of photosynthesis in pondweed are full of which gas?
Oxygen
What would increase the reliability of an experiment measuring the rate of photosynthesis?
Measuring the rate of photosynthesis multiple times per experiment
Increasing the reliability of an experiment can virtually always be done by …
repeating an experiment, collecting values, and calculating the average of the values.
What is a reason why measuring the number of gas bubbles produced per unit time is not a completely valid experimental method for measuring the rate of photosynthesis?
Not all of the gas in the bubbles is oxygen
Measuring the rate of photosynthesis by counting the number of gas bubbles produced per unit time makes the assumption that …
all the gas in the bubbles is oxygen.
Imagine you are designing an experiment which investigates how temperature influences photosynthetic rate in an aquatic plant such as pondweed.
You are provided with aquatic plants, beakers, water and a water bath, shown in the following image. How would you set up the apparatus you have been given?
Put the aquatic plant in a beaker that contains water.
Put the beaker that now contains water and the aquatic plant in the water bath.
Alter the temperature of the water bath for different runs of the experiment.
Why during the test of photosynthesis should you wait for ten minutes?
So the plant can acclimatise
Give two methods for how you could measure the photosynthetic rate.
Method 1
Count the number of bubbles of oxygen gas produced in one minute.
Method 2
Collect the oxygen gas produced by the plant in a syringe and measure the volume produced in one minute.
Organisms need energy for many reasons:
- Growth
- Homeostasis
- Contraction
Growth
To make larger molecules from smaller molecules. For example:
Glucose molecules can be joined together to produce starch (in plants).
Proteins can be made from amino acids in plants and animals.
In plant and yeast cells, ——- is converted into ethanol and carbon dioxide.
glucose
In plant and yeast cells, glucose is converted into …
ethanol and carbon dioxide
In plant and yeast cells,
Glucose →
ethanol + carbon dioxide
In plant and yeast cells,
——- → ethanol + carbon dioxide
Glucose
Glucose → ethanol + carbon dioxide
In yeast cells, this is called ————. This is an important step in the manufacture (making) of both bread and alcohol.
fermentation
In yeast cells, this is called fermentation. This is an important step in the manufacture (making) of both …
bread and alcohol.
In Anaerobic respiration in animals, glucose is not broken down completely, making it …
a less efficient way of transferring energy than aerobic respiration.
In Anaerobic respiration in animals, glucose is ——————-, making it a less efficient way of transferring energy than aerobic respiration.
not broken down completely
In Anaerobic respiration in animals, ——— is not broken down completely, making it a less efficient way of transferring energy than aerobic respiration.
glucose
Anaerobic respiration happens when …
insufficient (not enough) oxygen reaches the muscles during periods of intense activity.
What is the equation for anaerobic respiration ?
glucose→lactic acid
What is the word equation for Aerobic respiration (with oxygen)?
Glucose + oxygen → carbon dioxide + water (+ energy)
What is the letter equation for Aerobic respiration (with oxygen)?
C6H12O6 + 6O2 → 6CO2 + 6H2O (+ energy)
Types of respiration:
- Anaerobic
- Aerobic
Metabolism refers to …
all the chemical reactions that happen in an organism.
Combining glucose and nitrate ions to make …
amino acids.
Amino acids can then be combined to make …
proteins
Combining glycerol and fatty acid chains to make …
lipid molecules.
Glucose can be converted into …
starch (plants), glycogen (animals) and cellulose (plants).
Metabolic reactions include:
- Making amino acids
- Breaking down excess proteins
- Making lipids
- Converting glucose
Breaking down excess proteins to form ——-, which is excreted (got rid of) in urine.
urea
Exercise increases the body’s energy demands. The rate of respiration must …
increase in order to meet these new demands.
The main responses to increase the rate of respiration are:
- Increase in breath volume
- Increase in breathing rate
- Blood vessels dilate
- Increased heart rate
An increase in heart rate delivers …
more blood (containing glucose and oxygen) to the muscles.
Blood vessels ————- to ensure more blood reaches the muscles.
dilate (open wider)
An increase in breathing rate increases gas exchange in the lungs, with …
more oxygen taken in and more carbon dioxide released.
Lactic acid is a …
by-product of anaerobic respiration.
An increase in breath volume also …
increases the rate of gas exchange.
Lactic acid is toxic. When it builds up in muscles, this can cause …
muscular pain and fatigue.
Lactic acid is ——-. When it builds up in muscles, this can cause muscular pain and fatigue.
toxic
Oxygen debt refers to the …
extra oxygen that is needed after exercise to oxidise lactic acid and get it out of cells.
Blood transports the lactic acid to the ——- , where it reacts with oxygen to produce carbon dioxide and water.
liver
Blood transports the lactic acid to the liver, where it …
reacts with oxygen to produce carbon dioxide and water.
Heavy breathing after exercise helps to repay the oxygen debt by …
taking more oxygen into the lungs.
—————- after exercise helps to repay the oxygen debt by taking more oxygen into the lungs.
Heavy breathing
Name two things delivered in blood to muscles during periods of increased exercise?
- Oxygen
- Glucose
Respiration is a reaction that supplies …
all the energy needed by living organisms. The reaction can be aerobic (with oxygen) or anaerobic (without oxygen).
Anaerobic respiration happens without oxygen. Anaerobic respiration happens if:
- Insufficient oxygen reaches the muscles during periods of intense activity.
- There is not enough oxygen in the soil for plants.
In anaerobic respiration in plant and yeast cells, glucose is converted into ethanol and carbon dioxide. The carbon dioxide released from …
anaerobically respiring yeast cells is what causes bread to rise.
What is the name given to the sum of all the chemical reactions that happen in an organism?
Metabolism