Biology

• Magnification= size of image/size of real object
• Size of real object= size of image/magnification
• Calculati bc magnification= magnification of eye piece x magnification of the objective lens
• Eukaryotic cells have a cell membrane, cytoplasm and a nucleus.
• Prokaryotes have cytoplasm, cell membrane, cell wall. they have extra dna called plasmids.
• Diffusion is the movement of particles from an area of high concentration to an area of low concentration across the partially permeable gradient until they reach equilibriu.
• Osmosis is the movement of water particles from and area of high concentration to an area of low concentration across the partially permeable membrane
• HYPERTONIC: high solute outside the cell, low concentration inside
• ISOTONIC: same amount of concentration
• HYPOTONIC: low solute outside the cell, high solute inside the cell
• Turgid: A plant cell that has a high water potential and is swollen.
• Turgor: the state of turgidity and resulting rigidity of cells or tissues, typically due to the absorption of fluid
• in a hypertonic solution, a cells contents will leave via osmosis and the cell will become flaccid (soft)
• Plasmolysis: loss of water in a cell, causing the cell to shrink
• Active transport: The movement of molecules from an area of low concentration to an area of high concentration against a concentration gradient
• CELL CYCLE: stage 1: longest part of the cycle, the feel gets bigger, increases their mass and does normal cell activities. They replicate their dna and form two copies of each chromosome. Increase number of ribosomes, mitochondria and chloroplast.
• STAGE 2 CELL CYCLE: mitosis: the cell divides to produce two identical daughter cells
• Differentiate: To become different from others in a particular way.
• In plant cells, undiffere cells are at the stems and roots (meristems) of plants
• ZYGOTE: single cell formed by an egg and sperm cell.
• HOW ARE STEM CELLS DIFFERENT TO NORMAL CELLS?

  stem cells can divide and renew themselves

  they are unspecialised so don’t do specific functions
• Meristems in a plant can be used to clone plants.