sb1 key concepts of biology (paper 1 and 2) Flashcards
what are the stages of preparing a slide
- put on the slide
- thin layer of tissue
- add iodine to colour the cells
- add the colour slip
purpose of the nucleus
controls the cells activities
purpose of the cytoplasm
where chemical reactions take place
purpose of the cell membrane
controls what goes in and out of the cell
purpose of the mitochondria
- provides energy
- in the form of atp
- and the site of aerobic respiration
purpose of the ribosomes
- processes protein synthesis
purpose of the cell wall
- supports and strengthens the cell
purpose of the vacuole
- stores cell sap (excess water)
purpose of the chloroplasts
- the site of photosynthesis
compare plant and animal cells
- similarities: ribosomes, nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
- differentces: plant cells have a cell wall, chloroplast, vacuole
what are the three types of molucule movements ?
- active transport
- osmosis
- diffusion
what happens in diffusion ?
- movement of gas and liquid molecules
- high to low concentration
- known as passive movement as no extra energy is required
what happens in osmosis ?
- movement of water molecules
- high to low concentration
- known as passive movement as no extra energy is required
what happens in active transport ?
- movement of solid molecules
- low to high concentration (agaisnt the concentration gradient)
- known as active movment as energy is required
how do you test for startch
- add iodine to the solution
- if it turns black, it’s positive
- if it stays orange, it’s the same
how do you test for glucose
- add benedict solution
- heat it
- turns red (lots), orange (medium), green (little), stays blue (nothing)
how do you test for lipids
- add distilles water and some ethanol
- will turn cloudy if positive
- stays clear if negative
how do you test for protein
- add biuret solution
- goes from blue to purple if positive
- stays blue if negative
what are the steps of the core practical: potato osmosis
- get 5 pieces of potatoes (roughly same size)
- measure the initial mass
- pop the potato in the solutions, each solution having different sugar levels
- leave the potatoes for a bit
- measure the new madd then find out the percentage change using: (change in mass g / initial mass) x by 100
- the more sugar, the more mass the potato looses
what are the steps of the core practical: PH and enzymes
- add a drop of iodine in each well
- put amylase, pH and startch into a test tube
- add a drop of the solution into each well in 10 second intervals until the colour no longer changes
- repeat it with other pH’s
how can you make the core practical: PH and enzymes, more accurate
- repeat the eexperiment with the same pH multiple times
what happens in enzyme action
- enzymes and substrates randomly move about in solution
- the complementary substrate collides with its enzyme
- the complex forms and a reaction occurs
- the product(s) are then released of the enzyme
state what is meant by the optimum tempurature of an enzyme
the fastest tempurature in which it works at
what is the optimum tempurature of an enzyme
37 degrees celcius (woah thats kinda high)
how does the denaturing of an enzyme happen
- enzymes are held together by bonds
- high tempuratures or extremes of pH can disrupt or break the active site
- this is IRREVERSIBLE (( very very devastating :,( ))
