2c + d - Movement & Molecules Flashcards
What is active transport?
The movement of substances from a LOW concentration to a HIGH concentration using ATP (energy)
What do you use to test for starch?
Iodine
What do you use to test for reducing sugars like glucose?
Benedicts solution
What do you use to test for proteins?
Biuret
What do you use to test for lipids?
Ethanol and water
What results would you see when testing for starch?
Positive: blue/black
Negative: brown/orange
What results would you see when testing for reducing sugars?
Positive: green,yellow,orange or BRICK RED
Negative: blue
What results would you see when testing for proteins:
Positive: purple/violet
Negative: blue
What results would you see when testing for lipids?
Positive: milky/white mixture
Negative: clear/no colour
How does temperature affect enzyme activity?
An enzyme is at its OPTIMUM and works best at a certain a temperature (eg amylase at 37°C)
An enzyme will be more active at a slightly increased temperature because there is more energy and the particles move more, so there is a faster reaction. (If the temperature was too low there would be very little energy so a slow reaction)
At an extremely increased temperature the enzyme becomes DENATURED, the active site changes shape, so the substrate can not fit in anymore so can’t get broken down.
Suggest one safety precaution when carrying out the test for starch
Wearing safety goggles
Suggest one safety precaution when carrying out the test for glucose
Use tongs to put the tube in the water bath
Describe the steps of the glucose experiment:
- Put around a cm of chopped food into test tubes.
- Add a couple drops of Benedict’s solution.
- Put the test tubes in a water bath and leave for 5 minutes
Why do you chop the food up small when testing for glucose and starch?
So it has a large surface area and can react with the reagent quickly
Describe the steps of the starch experiment
- Add a small amount of food into the dimple tray.
- add a few drops of iodine.
What factors effect enzymes?
Temperature
pH level
What is transpiration caused by?
Evaporation of water from a plants surface
What is the transpiration stream?
A continuous flow of water up the xylem in the stems and roots
What are the functions of the transpiration stream
- water for photosynthesis
- Carries mineral ions
- water to keep the cells turgid
- evaporation which cools the leaf
What 4 factors affect the rate of transpiration and how?
Light intensity - increased as stomata open wider to allow more Co2 into leaf for photosynthesis
temperature - increased because evaporation + diffusion are faster at higher temperatures
humidity - decreased because diffusion of water Vapor out of leaf slows if leaf is already surrounded by moist air
windspeed - moving air removes water Vapor so rate of diffusion of water vapour from leaf increases
