biology topic 1 Flashcards
what is a microscope used for
to magnify small objects that would otherwise not be visible with the eye
What organelles are in animal cells
mitochondria, cytoplasm, nucleus, cell membrane
What organelles are in plant cells
chloroplasts, vacuole, cell membrane, cytoplasm, nucleus, cell wall, mitochondria
what does the nucleus do
controls the cell activities and contains genetic material (DNA)
What are eukaryotic cells
-contain genetic material within their nucleus
-the organelles are contained within membranes
- usually contain mitochondria
-contain ribosomes
-example- plant and animal cells
what are prokaryotic cells
-don’t contain membrane bound organelles
-much smaller than eukaryotic cells
-contain genetic material in small rings called plasmids in the cytoplasm
-contain ribosomes which make proteins for the cell
-example-bacteria
what does culture mean in science
to grow microorganisms (such as bacteria) for scientific study
What is commonly used to produce cultures of bacteria and other microorganisms
Petri dishes which contain a nutrient jelly called agar
How do you do aseptic technique
clean hands and workspace, light Bunsen burner and open it up to a blue flame which will sterilise the air around your workspace, pass an inoculating loop through the Bunsen flame to sterilise it, open the vial of sterilised water and pass the rim through the Bunsen flame, dip the inoculating loop into the sterilised water then reseal the vial, draw a Z shape on the agar plate with the inoculating loop then replace the lid, pass the loop through the flame again, use tape to secure lid (not completely around as it will make it airtight and oxygen won’t reach it) and incubate the plate for 48 hours at 25C (room temp)
What is the aseptic technique used for
to avoid contamination of equipment and allow an organism to be investigated at a time
What is a pathogen
bacteria that cause disease. Bacteria are able to divide and multiply rapidly which is why they can cause diseases
how do you calculate the final no. of bacteria
final no. of bacteria= initial no. of bacteria (always one)*2^number of divisions
how do you calculate magnification
magnification= size of image/ actual size of object
how many micrometres (μm) are in a millimetre?
1000
what does a ribosome do?
creates proteins for the cell
What does the nucleus do
controls cell activities and contains genetic material (DNA)
What is the cytoplasm
jelly like substance where chemical reactions occur
What does the cell membrane do
controls substances that enter and leave the cell
What do the chloroplasts do
contain chlorophyll which absorb sunlight for photosynthesis
What does the mitochondria do
site of aerobic respiration, contains lots of energy
What does the vacuole do
contains liquid that stores substances for the cell and keeps it rigid
what does the cell wall do
surrounds plants cells and provides strength and support
describe steps to view a cell sample under a light microscope
-select lowest power on objective lens
-turn coarse focus wheel until you can see the cells
-turn fine focus wheel until cells are in focus and you can see them clearly
why is it important to sterilise the culture medium and all the apparatus before use
to kill microorganisms/ prevent contamination
why shouldn’t the petri dish be incubated at a higher temperature than 25 degrees celscius
to prevent the growth of pathogens
sperm cell function and adaptations
function- fertilize egg during reproduction
adaptations- tail, mitochondria for energy
neuron (nerve cell) function and adaptations
function- transmit signals or impulses throughout the body
adaptations- long fibre (axon) to carry messages and dendrites to receive messages from other cells
leaf cell function and adaptations
function- responsible for photosynthesis
adaptations- chloroplasts
root hair cell function and adaptations-
function- absorb water, minerals and nutrients to be sent throughout the plant
adaptations- large surface area to increase rate of absorption
