The Processes of life Flashcards
What is the process whereby green plants make their food?
Photosynthesis
What is the end product of photosynthesis?
Glucose
What is glucose?
A sugar
What is respiration?
The process used by all organisms to release energy from food.
When do plants respire?
All the time, but only at night can we measure their respiration as during the day the photosynthesis uses up more CO2 than they produce.
What do organisms use energy for?
Think! - Anything from movement to active transport, keeping warm to producing the large molecules to grow
What is an enzyme?
A biological catalyst, a protein that speeds up reactions.
What is a protein made up of?
Amino acids. (Amine is a NH2 group)
How do cells know how to build an enzyme?
They use the genes
What are the chemicals that enzymes work on?
Substrates
What are the chemicals that are produce in the reaction?
Products
What is the shape of an enzyme?
A complex 3D shape that has an area for the substrate to fit into
What is the part of the enzyme that the substrate fits into?
Active site
What phrase is used to describe the model of how enzymes work?
Lock and Key
What do enzymes need to work at their optimum?
A specific pH and temperature
What is the body temperature of most mammals and birds?
Around 37C
What is the optimum temperature for most enzymes?
Around 37C
What happens to the reaction speed of a reaction (with an enzyme) as the temperature is increased?
The reaction speed increases as enzyme activity increases, up until the point where the protein is denatured by the heat
What happens to an enzyme if the pH changes too much?
The shape of the active site changes. If the change is permanent the protein is denatured.
What is photosynthesis?
It is a series of chemical reactions that use energy from sunlight to build large food molecules in green plants and phytoplankton
What is the overall word equation for photosynthesis?
Carbon dioxide and water —-light energy—–>glucose and oxygen
What absorbs the sunlight?
Chlorophyll
Where in the plant cell would you find the chlorophyll?
In the chloroplasts
Where in the plant cells would you find the enzymes used for photosynthesis?
In the chloroplasts
What is the product of photosynthesis?
Glucose
What is the glucose used for?
Chemicals needed for growth - cellulose, protein; starch to store energy; used for respiration
What is needed for the plant to synthesise amino acids?
Glucose and nitrates
What is produced as a waste product of photosynthesis?
Oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H2O —> C6H12O6 + 6O2
What is the basic unit of life?
The cell
What surrounds the cell?
cell membrane
Where do most of the reactions in the cell occur?
In the jelly-like cytoplasm
What does the cell membrane permit to pass freely?
Water and gases
What does the cell membrane not permit to pass through?
Larger molecules
What sort of membrane is the cell membrane?
Semi-permeable
What has a cell wall?
Cells of bacteria, plants and yeasts
What is a plant cell wall made from?
Cellulose
Where is the DNA (other than bacteria)
In the nucleus
Where do bacteria keep their DNA?
In the cytoplasm, a ring like structure
Where does respiration take place?
Mitochondria
Which organisms use mitochondria?
Animals, plants, microorganisms such as yeast
Where do bacteria keep the enzymes for respiration?
In the cell wall
What is diffusion?
The movement of chemicals from a high to a low concentration
How does carbon dioxide enter plant leaves?
By diffusion
How does oxygen leave plant leaves?
By diffusion
What do you call the movement of chemicals from a high to a low concentration?
Diffusion
Diffusion is….
passive, it requires no energy input from the organism
What is osmosis?
The movement of water from an area of high concentration to an area of lower concentration across a partially-permeable membrane
How do plants take up water?
By osmosis through the roots. (Note… if you are a very big tree you’d better have a plan B)
Why can plants not take up nitrate by diffusion?
They are usually found in higher concentration in plant cells than outside
How do plants take in nitrates?
Active transport
What does active transport need that diffusion does not?
Energy
Where does the energy for active transport come from?
Respiration
What limits the rate of photosynthesis?
Temperature, light, CO2
How is fieldwork on plants done?
A quadrat is put on the ground at random and all the plants within it are recorded. (Or a transect could be taken)
What information could you get from fieldwork done by quadrats?
Abundance and distribution of plants
How do living things obtain energy?
Respiration
Who respires?
Every living thing
What do we respire?
Glucose
What is the overall word equation for aerobic respiration?
Glucose + oxygen —> carbon dioxide + water + energy
Who uses aerobic respiration?
Plants, animals, some microorganisms
Why do organisms require the energy released by respiration?
Synthesis of large molecules; movement; warmth; etc
How do plants store the glucose produced by photosynthesis?
Starch.
Is there just one enzyme for respiration?
No, there are multiple stages and each has its own enzyme
What is the chemical equation for respiration?
C6H12O6+6O2 —> 6CO2 +6H2O
How do organisms respire without oxygen?
Anaerobic respiration
Why use aerobic respiration?
It releases more energy
Where does anaerobic respiration occur?
In our muscles when we exercise vigorously; plant roots in water logged soil; bacteria in deep wounds
What is the word equation for anaerobic respiration?
Glucose —> lactic acid + energy
What is fermentation?
A type of anaerobic respiration used by some organisms
What is produced by fermentation?
Alcohol (ethanol)
What is the word equation for fermentation?
glucose —-> ethanol + carbon dioxide + ENERGY
What type of respiration provides biogas?
Anaerobic
What makes bread rise?
The CO2 produced by yeast as it ferments
What makes alcoholic drinks sparkle?
The CO2 produced by yeast as it ferments
