cell biology Flashcards
(12 cards)
1
Q
function of mitochondria
A
site of aerobic respiration
2
Q
why do you dry the potato in osmosis practical after?
A
to ensure only mass of potato was measured
3
Q
why would potato pieces decrease in mass?
A
- water moves out
- by osmosis
- as there is a higher concentration of water inside the cell / a lower concentration of solution inside cell
4
Q
why would potato pieces increase in mass?
A
- water moves in
- by osmosis
- as there is a lower concentration of water inside the cell / a higher concentration of solution inside cell
5
Q
describe how mitosis produces two genetically identical cells
A
- cell gets larger and produces more sub-cellular structures
- DNA replicated to form two copies of each chromosome
- chromosomes pulled apart to each end of cell and nucleus divides
- cell membrane and cytoplasm divides to form two identical daughter cells
- sets of chromosomes in each new cell are identical to each other
6
Q
define specialised cell
A
a cell that has differentiated to perform a specific function
7
Q
why do sperm cells and cheek cells have a different number of chromosomes?
A
- sperm has a haploid nucleus as formed through meisos
8
Q
why does active transport need energy?
A
to move molecules against the concentration gradient
9
Q
how can you use a light microscope to make an image clearer?
A
- turn fine focus wheel
- until cells in focus
10
Q
method to prepare uncontaminated culture
A
- sterilise equipment before use
- pour sterile agar jelly into petri dish and set
- sterilise inoculating loop by passing it through a bunsen burner to kill bacteria
- dip inoculating loop into solution of microorganisms and make streaks with loop on surface of agar
- put the lid on petri dish and tape the lid shut but don’t fully seal as won’t get enough oxygen
- store upside down at 25°C to prevent harmful growth of bacteria and prevent condensation from dripping onto agar
11
Q
two aseptic techniques
A
- sterilise equipment
- sterilise agar jelly
12
Q
why is it important to use aseptic techniques?
A
- to prevent contamination
