B4 - The processes of life Flashcards
What is photosynthesis?
A series of chemical reactions that USES ENERGY from SUNLIGHT to PRODUCE FOOD.
What vital role does photosynthesis play in?
Making energy available to organisms through food chains.
What is respiration?
A series of chemical reactions that RELEASE ENERGY by breaking down large FOOD MOLECULES. It happens in EVERY LIVING CELL.
At night, what do plants do?
During the day, what do plants do?
They respire only and give out Carbon Dioxide.
During the the day, plants photosynthesise as well as respire. There will be a net output of oxygen.
What are enzymes?
Proteins that SPEED UP CHEMICAL REACTIONS.
What do enzymes consist of?
Long chains of AMINO ACIDS joined together.
Cells make enzymes according to…?
the INSTRUCTIONS carried in GENES.
What are SUBSTRATES?
The chemicals that enzymes work on.
What are PRODUCTS?
The chemicals produced in a reaction.
What does the Lock and Key Model show?
That molecules (substrates) have to be the correct shape to fit into the ACTIVE SITE of the enzyme.
What two factors affect the performance of enzymes?
pH and TEMPERATURE
If the pH is inappropriate or the temperature is too high, what will happen to the enzymes?
They will DENATURE (stop working).
What is the optimum temperature of MOST enzymes?
37 C
As the temperature increases, what happens to the enzyme activity and why does this happen?
As the temperature increases, enzyme activity INCREASES because the reaction rate INCREASES.
What can high temperatures do to enzymes?
It can change the shape of the active site of the enzyme. At a point where the change in shape is permanent, the enzyme has been denatured.
What can pH do to enzymes?
It also affects enzyme activity by change the shape of the active site. It can either be temporary or permanent.
What is the WORD equation for photosynthesis?
Carbon Dioxide + Water — (light energy) → Glucose + Oxygen
What is the SYMBOL equation for photosynthesis?
6CO2 + 6H2O – (light energy) → C6H12O6 + 6O2
What are the main stages of photosynthesis (3) ?
- Light energy absorbed by the green chemical chlorophyll
- Energy used to bring about the reaction between carbon dioxide and water to produce glucose (sugar)
- Oxygen produced as a waste product
What are 3 uses of glucose in plants?
- Converted into chemicals (e.g. cellulose, proteins, chlorophyll) needed for growth of plant cells
- Converted into starch for storage
- Used in respiration to release energy
What are the 7 components in the structure of a plant cell?
Cell membrane, cell wall, cytoplasm, nucleus, chloroplasts, mitochondria, large vacuole
What do chloroplasts contain in a plant cell?
They contain chlorophyll and the enzymes for the reactions in photosynthesis
What does the cell membrane allow in the cell?
Allow gases and water to pass in and out of the cell freely while presenting a barrier to other chemicals.
What does the nucleus contain in the cell?
DNA which carries the genetic code for making enzymes and other proteins used in the chemical reactions of photosynthesis
What is the cytoplasm represent in the plant cell?
A jelly-like fluid where the enzymes and other proteins are made. It contains enzymes used in anaerobic respiration.
What do the mitochondria do in the cells?
Contains enzymes needed for the reactions of AEROBIC RESPIRATION.
What are minerals taken up by plant roots used for?
Making some chemicals needed by cells, including nitrogen from nitrates to make proteins
What is DIFFUSION?
The PASSIVE OVERALL MOVEMENT of MOLECULES from a region of their HIGHER CONCENTRATION to a region of their LOWER CONCENTRATION.
During photosynthesis, which gas exchanges occur by diffusion?
The movement of OXYGEN and CARBON DIOXIDE in and out of the leaves.
What is OSMOSIS?
The OVERALL MOVEMENT of WATER from a DILUTE to a more CONCENTRATED solution through a PARTIALLY PERMEABLE MEMBRANE.
In terms of the plants, where does osmosis occur?
The movement of water into plant roots
What is ACTIVE TRANSPORT?
The OVERALL MOVEMENT of CHEMICALS across a CELL MEMBRANE from a region of LOWER CONCENTRATION to a HIGHER CONCENTRATION using ENERGY released by respiration.
When is Active Transport used in terms of plants?
In the absorption of nitrates by plant roots.
What are the 3 limiting factors of the rate of photosynthesis?
- TEMPERATURE
- CARBON DIOXIDE
- LIGHT INTENSITY
As the level of Light Intensity / Carbon Dioxide increases, what happens to the rate of photosynthesis?
It also increases steadily but UP TO A CERTAIN POINT. The graph will flatten off which will mean that Light Intensity / Carbon Dioxide will no longer be a limiting factor.
If the temperature is the limiting factor, what is the reason behind this?
The temperature is too low - the enzymes needed for photosynthesis work more SLOWLY at low temperatures.
If the plant is too hot, what will happen to the enzymes?
The enzymes will become denatured (and its other reactions).
What is the certain temperature at which enzymes start to denature in plants during photosynthesis?
45 C
What are the 3 techniques that are used to investigate the effect of light on plants?
- LIGHT METER
- QUADRANT
- IDENTIFICATION KEY
What is a Light Meter used for?
e.g. if you were comparing lights in areas with different levels of light, you could use a light meter which is a sensor that ACCURATELY MEASURES LIGHT LEVEL.
What is a Quadrat used for?
e.g. you can estimate the percentage cover of a plant species on the ground. This is a quick and easy method. You ‘throw’ a square frame on a particular region and count how many squares there are.
If a species covers more than half of a square in a quadrat, what do you do?
You count it as a whole square.
What is an Identification Key used for?
It’s a series of questions that you can use to figure out what a plant is. You start at Question 1 and the answers narrow down your options of what the plant could be until you end up with one possible species your plant could be.
What does a Transect investigate?
How something changes across an area.
How do you take a transect?
- Run a tape measure between two fixed points.
- Start at one end of the transect and collect the data you want.
- Move along the transect and collect the data again.
- Keep collecting data and moving until you reach the end of the transect.
What is an example of a situation where you would use a transect?
e.g. if you were investigating the effect of light on the distribution of plant species, you could take a transect across an area where the light level changes (e.g. from woodland into an open field). You could collect data on how the percentage cover of different species change across the transect.
What do ecologists investigate in terms of the plants?
The ABUNDANCE and DISTRIBUTION of plants:
- At different locations in an area, and make a comparison
- In different areas, and make a comparison
What needs to be taken into account when investigating the effects of plants/photosynthesis?
Other factors, e.g. competition for nutrients
What are 3 examples of chemical reactions where energy is required by all living organisms?
- Movement
- Synthesis of large molecules
- ACTIVE TRANSPORT
What are two examples of synthesis of large molecules?
- Glucose is joined together to make things like starch and cellulose in plant cells.
- In plant cells, animal cell and microorganisms, GLUCOSE AND NITROGEN are joined together to make AMINO ACIDS. The amino acids are joined together to make PROTEINS.
What are the 2 types of respiration?
AEROBIC AND ANAEROBIC
Where does Aerobic Respiration take place and what does it require?
It takes place in animal and plant cells and in SOME microorganisms.
It requires OXYGEN.
What is the WORD equation for Aerobic Respiration?
What is the SYMBOL equation for Aerobic Respiration?
glucose + oxygen → carbon dioxide + water (+ ENERGY)
C6H12O6 + O2 → 6CO2 + 6H2O (+ ENERGY)
Where does Anaerobic Respiration take place and what does it require?
Animal, plant and SOME microbial cells.
It requires a condition of LOW or ABSENCE of oxygen
Specifically, what are 3 examples of locations where anaerobic respiration takes place?
- PLANT ROOTS in WATERLOGGED SOIL
- BACTERIA in PUNCTURE WOUNDS
- HUMAN CELLS during VIGOROUS EXERCISE
What is the WORD equation for Anaerobic Respiration taking place in ANIMAL CELLS and SOME BACTERIA?
Glucose → Lactic Acid (+ ENERGY released)
What is the difference between anaerobic respiration and aerobic respiration in terms of the energy released?
Anaerobic respiration releases less energy per glucose molecule than aerobic respiration.
What is the WORD equation for Anaerobic Respiration taking place in PLANT cells and SOME MICROORGANISMS (e.g. yeast)?
Glucose → Ethanol + Carbon Dioxide (+ ENERGY released)
Name all the structures in an animal cell.
NUCLEUS, CYTOPLASM, CELL MEMBRANE, MITOCHONDRIA
Name all the structures in a yeast cell.
NUCLEUS, CYTOPLASM, CELL MEMBRANE, CELL WALL, MITOCHONDRIA
Name all the structures in a bacteria cell.
CIRCULAR DNA MOLECULE, CYTOPLASM, CELL MEMBRANE, CELL WALL
What is Fermentation?
A type of anaerobic respiration used by some microorganisms which break down sugars into other products as they respire anaerobically.
What are 3 uses of fermentation?
- BIOGAS
- BREAD
- ALCOHOL
How is biogas produced by microorganisms?
They ferment plant and animal waste, which contains carbohydrates. The biogas they produce is mainly made of METHANE and CARBON DIOXIDE.
How is BREAD made by yeast?
The yeast FERMENT the CARBOHYDRATES in the flour and release CARBON DIOXIDE which causes the bread to rise.
How is ALCOHOL made by yeast?
The yeast FERMENT the SUGAR to form ALCOHOL (ethanol). The sugar used in alcohol production comes from things like grapes (wine) or barley (beer).
