Photosynthesis Flashcards
What is photosynthesis
An endothermic process used by plants to convert carbon dioxide and water into glucose and oxygen using energy in sunlight.
Word equation for photosynthesis
water + carbon dioxide → glucose + oxygen
Symbol equation for photosynthesis
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
What are chloroplast
An organelle that contains chlorophyll and in which photosynthesis takes place.
What are chlorophyll
Green pigment in plants that absorbs light energy used to carry out photosynthesis.
Endothermic
(absorbs heat)
A chemical reaction that requires a net input of energy
Adaptations of leaves for photosynthesis
Broad, thin, veins, cells packed with chloroplasts, waxy cuticle, stomata.
What are stomata?
Small openings on the underside of a leaf through which oxygen and carbon dioxide can move.
What are guard cells?
Cells that control the opening and closing of the stomata.
What are palisade mesophyll
Layer of cells packed with chloroplasts, where most photosynthesis occurs.
What are spongy mesophyll?
Layer of irregularly shaped cells with air spaces to allow gases to diffuse in and out of cells.
What are waxy cuticle?
A waterproof barrier that protects the leaf and prevents water loss.
What is gas exchange?
The transfer of gases between an organism and its environment
What is vascular bundle
Clusters of xylem and phloem tissue in stems.
What is Xylem
Tissue that transports water and dissolved minerals in vascular plants.
What are phloem?
Tissue that transports sugars in vascular plants.
Factors that affect the rate of photosynthesis
Light intensity
Temperature
Carbon dioxide
Chlorophyll
What is meant by ‘Limiting Factor’
A factor in short supply that prevents the rate of reaction from increasing.
Why carbon dioxide can be a limiting factor
Carbon dioxide is a raw material for photosynthesis.
Why light intensity can be a limiting factor
Light provides the energy that is needed for photosynthesis.
Why temperature is a limiting factor
If the temperature is too low the enzymes work slowly. If the temperature is too high the enzymes are denatured and do not work.
Why chlorophyll is a limiting factor
Chlorophyll is needed to absorb the light energy used to carry out photosynthesis
Importance of limiting factors
Farmers and commercial growers can artificially create the ideal environment to grow plants.
Five uses of glucose
For respiration Making cellulose Making amino acids Stored as oils or fats Stored as starch
What is Cellulose
A polymer made of glucose used to build plant cell walls
What is starch?
An insoluble polymer made of glucose that is used for storage.
What is respiration?
The chemical process that takes place in cells and releases energy from glucose in the presence of oxygen.
What are Amino Acids
The building blocks of proteins. Formed by combining glucose with nitrate ions.
What are fats and oils
Storage compounds found in seeds.
What is the concentration gradient?
A difference in concentration between two areas next to each other
What is diffusion?
The net movement of particles from an area of high concentration to an area of lower concentration.
What is Passive Transport?
Happens due to the random motion of particles. No energy is required.
What is osmosis?
The movement of water molecules across a partially permeable membrane from a a region of higher water concentration to a region of lower water concentration.
What is active transport?
The movement of molecules from a region of low concentration to a region of high concentration. This requires energy.
What is a semi-permeable membrane?
A membrane that allows only certain molecules to pass through.
Adaptation of root hair cells
A large surface area for absorption.
What is Rose black spot
A parasitic fungus that causes black spot on roses.
What is Tobacco Mosaic Virus?
A virus that affects plants. It causes stunted growth and causes leaves to discolour, curl and have yellow streaks or spots.
What is chlorosis?
Yellow leaves caused by a lack of magnesium which is needed to produce chlorophyll.
What are physical defences on plants
Layers of dead cells around stems
Tough waxy leaf cuticles
Cellulose cell walls
How is rose black spot treated?
Removing infected dropped leaves and burning them.
Pruning shoots in the spring.
Treating infections with fungicides.
How is rose black spot transmitted?
The fungus produces spores which are released in wet, humid conditions.
How does black spot fungus affect the growth of roses?
Damaged leaves cannot photosynthesise efficiently.
How can plant diseases be identified?
Stunted growth. Spots on leaves. Areas of decay. Discolouration. Presence of pests.
