Biology Unit 2A

A mind map of the UNIT2A topics in GCSE biology, CELLS and PLANTS. This is from the AQA specification. Its purpose is for easy revision of key points. 

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  • Biology Unit 2
    • CELLS
      • Cell Features
        • ANIMALS- nucleus, cytoplasm, ribosomes, mitochondria, cell membrane
        • Plant-nucleus, cell wall, cell membrane, vacuole, chloroplasts, cytoplasm, mitochondria, ribosomes
      • Specialized Cells
        • CONE CELL- Visual Pigment, detects light and sends stimulus to the brain. concentrated in the retina.
        • ROOT HAIR CELL- Root Hair, it has a large surface area so it can collect more water through diffusion.
        • SPERM CELL- Tail, stream lined head. it has a long tail for fast mobility and its head is streamlined.
        • FAT CELL- Fat Store, it stores extra fat as its cell wall can expand.
      • Diffusion/ Osmosis
        • OSMOSIS
          • If a body cell is surrounded by a high salt concentration, the size of the cell will decrease as more water is being passed out of the cell to create an equilibrium
          • If a cell is surrounded by pure water it makes the cell inflate due to the cell trying to reach an equilibrium through osmosis.
        • DIFFUSION
          • The spreading out of particals from a high concentration to a low concentration
          • spreads out until it meets an Equilibrium
      • Tissues, Organs and Organ Systems
        • Tissues are a group of similar cells that work together to carry out a specific function
          • Muscular Tissue
          • Glandular Tissues
          • Epithelial Tissues
        • Organs  are structures of cells of the same and different type that work together to carry out a specific function.
          • The Heart
          • The stomach
          • The large intestine
        • Organ Systems are groups of organs that work together to carry out a specific function
          • Digestive System
            • Saliva Glands, Liver, Stomach, Gall Bladder , Pancreas, Small Intestine, Large Intestine
          • Respiratory
          • Circulatory
    • PLANTS
      • Photosynthesis Limiting Factors
        • CO2
          • as the CO2 levels increase so will the rate of photosynthesis but will eventually level off due to the other limiting factors.
        • LIGHT INTENSITY
        • TEMPERATURE
          • As the temperature around a plant increases so will the rate of photosynthesis. until the temperature reaches a certain level inwhich it will suddenly decline. This is because the enzymes in the plant denature.
      • Glucose in plants
        • Glucose is used to makes starch as starch is insoluble so no glucose is wasted.
        • GLUCOSE USES
        • Plants make glucose when they photosynthesis and goes towards:
          • Cell Functions, Growth, Reproduction, Storage
      • Organisms
        • DISTRIBUTION
          • Factors Effecting Distribution
            • O2
            • Light
            • Temperature
          • Light - more plants in areas with more light, plants get taller and grow earlier in the season
  • The movement of water across a selectively permeable membrane
    • OSMOSIS
      • If a body cell is surrounded by a high salt concentration, the size of the cell will decrease as more water is being passed out of the cell to create an equilibrium
      • If a cell is surrounded by pure water it makes the cell inflate due to the cell trying to reach an equilibrium through osmosis.
    • Movement due to a concentration gradient
    • Important in red blood cells, kidney tubes and the large intestine
  • As the levels of light increases so will the rate of photosynthesis but will eventually level off due to other limiting factors.
    • LIGHT INTENSITY
  • GLUCOSE -> LIPIDS
    • GLUCOSE USES
  • GLUCOSE -> CELLULOSE
    • GLUCOSE + NITRATES -> AMINO ACIDS
      • GLUCOSE -> CHLOROPHYLL
        • Climate
          • Factors Effecting Distribution
            • O2
            • Light
            • Temperature
        • PH of soil
          • Space
            • Water
              • CO2
                • Nutrients Avalible
                  • CO2- more plants in areas with high amounts of CO2, plants will have larger leaves= more surface area
                    • DISTRIBUTION
                      • Light - more plants in areas with more light, plants get taller and grow earlier in the season
                  • O2- more plants in areas with high levels of O2, plants have more STOMATA and the STOMATA stay open for longer
                    • Water- more plants grow around water sources, more root hair cells are present to take in water, large/shallow roots
                      • Measuring Distribution
                        • Organisms
                          • SAMPLING
                            • Count the organisms in the QUADRAT
                            • the areas must be random
                            • you must sample more than 1 are  so the mean number can be calculated, know as QUANTATIVE SAMPLING
                            • Date Collection
                              • EG. 10 Quadrats of an area of 0.25m2 were used. what is the total area of the area sampled?
                                • 0.25X 10 = 2.5M2
                          • TRANSECTS
                            • line transects are most commonly used
                            • tape is stretched between two points
                            • Sampling is carried out at regular intervals along the transect

                        Comments

                        Rose Yemelyanova

                        thank you - this is a basic and good summary of B2. From here, I know straight away what things I know for sure, and what things I don't know as well.

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