B4 Flashcards
The basic processes of life carried out by all living things depend on what?
Chemical reactions within cells that require energy (released by respiration)
Describe phtosynthesis
A series of chemical reactions that use energy from sunlight to build large food molecules in plant cells and some micro-organisms (e.g. phytoplankton)
Describe respiration
A chemical reaction that release energy by breaking down large molecules in all living things
What is an enzyme?
They are biological catalyst that speed up the rate of reactions
Where are enzymes made?
In the cytoplasm of the cell
Cells make enzymes according to what?
The instructions carried in the genes
Describe the lock and key model
Molecules have to be in the correct shape to fit the active sit of an enzyme. (essentially the substrate has to fit the active site)
The specific constant temperature that enzymes need to work best is called what?
The optimum temperature
If temperature gets too high, what happens to the enzyme?
The enzymes becomes denatured and will permanently stop working
What is enzyme activity at different temperatures a balance between?
Increased rate of reaction as temperature increases and changes to the active site at higher temperatures which may lead to denaturing
The pH at which the enzyme works best is known as what?
The optimum pH
What happens to an enzyme if it is conditions are different to its optimum pH?
The active site can change shape and it may no longer work because the enzyme-substance complex cannot form
State the word equation for photosynthesis
carbon dioxide + water and light energy = glucose +oxygen
State the balanced symbol equation for photosynthesis
6CO2 +6H20_C6H12O6 +6O2
Recall the three main stages of photosynthesis;
- Light energy is absorbed by the green chemical chlorophyll
- energy is used to bring about the reaction between carbon dioxide and water to produce glucose
- Oxygen is produced as a waste product
Minerals taken up by the plant roots are used tom make what?
Chemicals needed by cells including nitrogen from nitrates to make proteins.
Name the 6 structural features of a plant cell.
- Cell wall
- Vacuole
- Chloroplasts
- Cell membrane
- Cytoplasm
- Nucleus
Describe the function of chloroplast
They contain chlorophyll and the enzymes for the reaction in photosynthesis
Describe the function of the cell membrane
It allows gases and water to pass in and out of the cell freely while presenting a barrier to other chemicals
Describe the function of the nucleus in a plant cell
It contains DNA, which carries the genetic code for making enzymes and other proteins in the chemical reactions of photosynthesis
Describe the function of the cytoplasm in a plant cell
This is where the enzymes and other proteins are made
Define diffusion
It is the passive overall movement of molecules from a region of higher concentration to a region of their lower concentration
Define osmosis
It is the overall movement of water from dilute to more concentrated solution through a partially permeable membrane
The movement of water into plant roots occurs by which process?
Osmosis
Define active transport
Movement of chemicals across a cell membrane requiring energy from respiration( chemicals move against the concentration of the gradient)
How do plant root absorb nitrates?
Using active transport
The rate of photosynthesis may be limited by what three factors?
- Temperature
- Carbon dioxide
- Light intensity
How is a light meter used in fieldworks?
A light meter is used to measure light intensity
How is a quadrant used in fieldwork?
A quadrant is used to see how many animals or plants are present in a certain area
How is identification key used in field works?
An identification key is used to identify species present in the fieldwork
How do you take a transect?
A transect is straight line that runs through a location upon which data on organisms distribution can be recorded
All living things require energy released by respiration, What are the three men uses of this energy?
- Movement
- Synthesis of large molecules
- Active transport
Describe examples of the synthesis of large molecules
Synthesis of polymers required by plant cells such as starch and cellulose from glucose in plant cells.
Synthesis of amino acids from glucose and nirates and then proteins from amino acids in plants , animals and microbial cells
Aerobic respiration takes place in animal and plant cells as well as some micro-organisms : what does it require?
Oxygen ( and glucose)
State the word equation for aerobic respiration
Glucose + oxygen = Carbon dioxide + water (energy released)
Anaerobic respiration take place in condition of low or no oxygen. Give three examples of this.
- In plant roots in water logged soil
- In bacteria in puncture wounds
- In humans cells during vigorous exercise
State the word equation for anaerobic respiration in animals cells and some bacteria.
Glucose = lactic acid ( +energy released)
What is the word equation for anaerobic respiration in plant cell and some micro-organisms
Glucose = ethanol + carbon dioxide(+ energy released)
In terms of energy released per glucose molecule, what is the difference between aerobic and anaerobic respiration?
Aerobic respiration releases more energy per glucose molecule
What are the 4 structural features of an animal cell?
- Cytoplasm
- Cell membrane
- Nucleus
- Mitochondria
What 5 structural features of a bacteria cell?
- Nucleus
- Mitochondria
- Cell wall
- Cell membrane
- Cytoplam
What is the function of mitochondria in cells?
They contain enzymes for the reaction in aerobic respiration (in animals ,plants and yeast)
What is the function of the cytoplasm?
It is where are made and it also contains the enzymes use in anaerobic respiration
Describe the use anaerobic respiration in foods?
Anaerobic respiration takes place in yeast and some bacteria , producing ethanol and carbon dioxide . They have been used in the making of many foods such as bread , yoghurt and vinegar.
Describe the use anaerobic respiration in fuels?
When fermentation is performed on larger scale using yeast, water sugar and some nutrients bio-ethanol can be used as a fuel.
Describe the use anaerobic respiration in Biogas?
Bio gas is a fuel manufactured using animal manure ( and sometimes human waste) Biodegesters are used to convert the manure into bio gas. Bacteria inside the biodigester break down parts of the manure and produce methane gas. This can be used as a fuel to run generators and heat buildings. This method of fuel production is more commonly used in developing countries
