B2.1 Flashcards
What is diffusion?
Diffusion:
- Net movement of particles from a high to low concentration
What factors affect diffusion?
Factor affecting diffusion:
- Surface area
What is osmosis?
Osmosis:
- Net movement of a solvent from high to low concentration
- Through semi-permeable membrane
What happens if cell is placed in isotonic solution?
Isotonic solution:
- Water potential is same
- Cell remains same
What happens if cell is placed in dilute solution?
Dilute solution:
- Water enters cell
- Swells up
What happens if cell is placed in concentrated sugar solution?
Concentration solution:
- More free water in cell than solution
- Water moves out of cell
- Cell will shrivel
- Plasmolysis
What happens if red blood cell placed in dilute solution.
Dilute solution:
- Water potential higher than cell
- Cell will burst
- Lysis
What happens if red blood cell placed in same solution concentration?
Same concentration:
- Water potential same
- Cell remains same
What happens is red blood cell placed in concentrated solution?
Concentrated solution:
- Water potential higher in cell than in solution
- Water leaves cell
- Cell becomes crenated
What is active transport?
Active transport:
- Movement of a substance from low to high concentration
- Against concentration gradient
- Uses ATP
How does active transport work?
Active transport:
- Carrier proteins span across width of cell membrane
- Scoops molecules in low concentration
- Rotates 180 and releases molecule into cell
- Rotates back
Where does active transport happen in humans?
Active transport in humans:
- Digestion
- Glucose naturally diffuses until equilibrium
- Glucose is essential
- Carrier protein scoops rest of glucose in low concentration
What is mitosis?
Mitosis:
- Body cells dividing
Why do body cells divide?
Body cells divide to:
- Replace worn out cells
- Repair damaged tissue
- Growth in organism
What are the steps in mitosis?
Mitosis steps:
- Chromosomes form X shape
- Nucleus disappears
- Chromosome line up at centre
- Chromosomes separate and move to opposite ends of the cell
- Two daughter cells are formed
What is cell differentiation?
Cell differentiation:
- Cells have ability to become what ever they want
What are stem cells?
Stem cells:
- Unspecialised cells
What are embryonic stem cells?
Embryonic stem cells:
- Can differentiate into any cell
- Nerve cells, muscle cells, brain cells etc
What are adult stem cells?
Adult stem cells:
- Found in bone marrow, skin, liver
- Does not differentiate into many types of stem cells
What is leukemia?
Leukemia:
- Need defected blood cells destroyed
- Inserting needle in the hip
- Stem cell will enter and differentiate to produce healthier blood cells
What are stem cells in plants?
Stem cell in plants:
- Ability to continue differentiating throughout their life
What are meristem cells?
Meristem cells:
- Found in all growing parts of plant
- Stem cells found in meristem cells
