Biology Topic 6 Plants Flashcards
upper epidermis adaptions and how this feature helps the leaf
- waxy cuticle- reduces water loss
- No chloroplasts/transparent - lets lots of light through to palisade mesophyll
palisade mesophyl adaptions and how this feature helps the leaf
- lots of chloroplasts- absorbs light and carry’s out photosynthesis
spongy mesophyl adaptions and how this feature helps the leaf
- Air spaces- speeds up gas exchange
- xylem tissue- supplies water and minerals to the leaf
- phloem tissue- Supplies dissolved sugars to the leaf
lower epidermis adaptions and how this feature helps the leaf
- guard cells-can shut stomata to reduce water loss
- Stomata allows co2 to diffuse
xylem tissue adaptions and how this feature helps the leaf
- No end wall- allows water and mineral ions to flow from cell to cell
- Lignin in cell wall- strengthens the cell wall
- Dead and hollow cell- allows water to flow through cell easily
phloem tissue adaptions and how this feature helps the leaf
- very little cytoplasm-allows dissolved sugars to flow through cell easily
- Pores(holes) in end walls-Allows dissolved sugars to flow from one cell to another
photosynthesis equation
carbon dioxide + water →light above arrow glucose + oxygen
The glucose produced in photosynthesis may be:
used for respiration
converted into insoluble starch for storage
used to produce fat or oil for storage
used to produce cellulose, which strengthens the cell wall
used to produce amino acids for protein synthesis. To produce proteins, plants also use nitrate ions that are absorbed from the soil.
Describe photosynthesis
an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light.
vascular bundle is
the xylem and phloem
CO2, H2O, O2
C6H12O6 .
carbon dioxide
hydrogen
oxygen
glucose
food tests to identify sugars
Method
Take a sample of the food/biological material to be tested and grind up
Then..
Dissolve the ground up food in a test tube of water
Add a few drops of Benedict’s solution
Heat (in a beaker of boiling water)
Positive result (if the substance is present)
Colour changes from blue to green / orange / red (increasing quantities of sugar present)
food tests to identify starch
Method
Take a sample of the food/biological material to be tested and grind up
Then..
Dissolve the ground up food in a test tube of water
Add a few drops of iodine solution
Colour changes from yellow/orange to black
food test for Protein
Method
Take a sample of the food/biological material to be tested and grind up
Then..
Dissolve the ground up food in a test tube of water
Add a few drops of biuret solution (a mixture of sodium hydroxide and copper sulphate)
Colour changes from blue to purple
Fat food test
Method
Take a sample of the food/biological material to be tested and grind up
Then..
Dissolve the ground up food in a test tube of ethanol
Pour the ethanol into a test tube of water
Water changes colour from colourless to white emulsion
Photosynthesis experiment method
Simple method (method writing guide)
Fill a boiling tube 2/3rds full of sodium hydrogen carbonate solution
Place boiling tube in a beaker of water (room temperature water bath)
Cut a 7cm piece of pondweed (Elodea) and place cut side up in your boiling tube
Turn off all lights in the room
Place the beaker 10cm from a lamp and leave for 5 minutes
Then count the number of bubbles of oxygen produced in 1 minute and record.
Repeat at 20cm, 30cm, 40cm and 50cm
Independent variable
Dependent variable
Control variables
Distance from the lamp (affects light intensity)
Number of bubbles of oxygen
Brightness of lamp
Colour of the light
Concentration of sodium hydrogen carbonate
Temperature
Length of pondweed
Type / species of pondweed
Why did we turn off all the other lights in the room?
To reduce background light that could affect rate of photosynthesis in the plant
How did we control the temperature?
Place the tube containing the pondweed into a beaker of water (room temperature water bath)
What was the purpose of the sodium hydrogen carbonate?
Dissolves to release CO2, which can be used by the pondweed for photosynthesis
Suggest an experimental control
Set up the same experiment with no light
Describe the main sources of error
Miscounting the bubbles (dependent variable)
Bubbles may be different sizes (dependent variable)
Distances may not be measured accurately (independent variable)