Yr 9 Cell division Flashcards
Define Diffusion
Movement of particles from an area of higher concentration to an area of lower concentration
A bacterium has a length of 0.002mm in real life and is magnified by 200 times. How large is this image?
0.4mm
Define the term osmosis
Osmosis is the movement of water from an area of higher concentration to an area of lower concentration via a partially permeable membrane - essentially diffusion.
Why is osmosis vital for life?
Osmosis allows cells to maintain the balance of water and solutes inside and outside of the cell.
What reagent is used to test for starch in a food and what does a positive result look like?
Iodine is used to test for starch. A positive result makes the food turn dark blue.
Explain why a red blood cell bursts if placed in water.
The water will move from the concentrated solution (water) to the less concentrated solution (cytoplasm of the red blood cell). As the red blood cell has no cell wall, it will keep taking water. This will make it burst.
What is the function of the mitochondrion?
To carry out aerobic respiration within the cell to produce energy.
Define the term active transport.
Movement of molecules against the concentration gradient (low to high). This requires energy.
Describe how to carry out the test for proteins. What is the test called? What does a positive result look like?
The biuret test. Add potassium hydroxide and two drops of copper sulfate. A purple colour shows if protein is present.
Explain why a piece of potato will gain mass when placed in distilled water.
The water will move into the cells of the potato, across the partially permeable membrane, from a higher concentrated solution (water) to a lower concentrated solution (cytoplasm of potato cells). This is essentially osmosis.
Explain why electron microscope images show more detail than light microscope images.
They have a higher resolution and higher magnification.
What features do eukaryotic cells have that prokaryotic cells do not have?
Membrane bound organelles, such as a nucleus.
What is a prokaryote and eukaryote?
A prokaryote is a simple, usually unicellular organism that does not have membrane-bound organelles whilst eukaryotes are complex, usually multicellular organisms that have membrane-bound organelles like a nucleus.
How do bacteria store genetic information?
Bacteria store genetic information via non membrane-bound organelles such as plasmids or a nucleus.
