Biology Y9 Flashcards
What is a eukaryotic cell?
A cell where the DNA is in the nucleus and all organelles are membrane bound.
What is the equation for magnification?
Image size ÷ actual size
What is aseptic technique?
Preventing contaminating from pathogens (bacteria)
What factors affect the growth of microorganisms?
-temperate
-nutrients
-oxygen levels
-pH
Why does cell division take place?
Growth
Repair
Replace
What are the stages of cell division?
Stage 1- DNA replicated to form 2 copies of each chromosome. Number of sub-cellular structures increases
Stage 2- Mitosis: the nucleus divides
Stage 3- Cytoplasm and cell membrane divide leaving 2 identical daughter cells
Where are stem cells found?
Bone marrow (adult stem cells)
Embryo (embryonic)
Shoot tips (meristems)
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration
What factors affect the rate of diffusion?
temperature- higher = quicker
distance to travel
surface area of the cells
concentration- bigger the difference = quicker
What is osmosis?
The movement of water from a dilute solution (high water concentration) to a concentrated solution (low water solution) across a partially permeable membrane.
What are the differences and similarities between electron and light microscopes?
Light microscopes:
Use a beam of light
Cheaper
Lower magnification
Electron microscopes:
Use a beam of electrons
Very expensive
Higher magnification
What is the equation for image size?
Actual × magnification
What is the equation for actual?
image ÷ magnification
What organelles do plant cells have that animal cells do not?
Chloroplasts
Vacuole
Cell wall
What is the function of the ribosomes?
Protein synthesis
