bio rps

Question 1

microscopes

Answer 1

add a drop of water
cut up an onion, separate into layers
place epidermal tissue into the water on the slide
add a drop of iodine to stain
place a cover slip on top - carefully lower so there are no air bubbles

clip slide onto stage
select lowest objective lens
use coarse ajustment knob to move stage up to just below lens
look down eyepiece, ajust coarse knob to bring it into rough focus
then adjust fine focus
can swap to a higher powered objective lens

draw using a pencil that is sharp
draw clearly with no colouring or shading
draw in proportion
title and magnification
label

Question 2

microscopes short

Answer 2

prepare slide with a drop of water, place tissue on the water and add a drop of iodine. then add the cover slip, dont trap any air. clip slide onto stage, lowest lens, move it up, use coarse then fine focus. swap lens if needed.
draw clearly and in proprotion. add title and magnification, then label

Question 3

culturing microorganisms

Answer 3

grow in agar plates, as a lawn (spread) or streaked (streak, then flame and cool loop, repeat). harmful pathogens are more likely to grow above 25 degrees fyi. place paper discs soaked in different types/concentrations of antibiotics on an agar plate, leave space. antibiotic should soak into jelly - a clear area will be seen where they die called an inhibition zone. use a control soaked in sterile water
leave plate for 48 hours
measure the biggest inhibition zone

Question 4

avoiding contanimation - microorganisms

Answer 4

sterilise inoculation loop by passing it through a flame
lightly tape on lid to stop microoragnisms from the air getting in
dont seal properly to prevent dangerous anaerobic pathogens
store upside down to stop condensation falling onto agar surface

Question 5

how sugar solutions affect plant tissue

Answer 5

cut up potato into identical cylinders. get beakers with different sugar solutions from pure water to very concentrated (0, 0.2, 0.4, 0.6, 0.8, 1)
measure mass of potato, leave in beaker for 24ish hours
remove, dry, and remeasure mass
calculate percentage change
repeat to avoid errors e.g not drying potato cylinders fully, water evaporating from beakers