Biology Topic 1 - Cell Biology

    Cards (169)

    • When someone first peered down a microscope at a slice of cork and drew the boxes they saw, little did they know that they'd seen the building blocks of every organism on the planet
    • Organisms can be
      • Prokaryotes
      • Eukaryotes
    • All living things are made of cells
    • Cells
      • Can be either prokaryotic or eukaryotic. Eukaryotic cells are complex and include all animal and plant cells. Prokaryotic cells are simple, e.g., bacteria
    • Parts of most animal cells
      • Nucleus
      • Cytoplasm
      • Cell membrane
      • Mitochondria
      • Ribosomes
    • Parts of plant cells
      • Rigid cell wall
      • Permanent vacuole
      • Chloroplasts
    • Bacterial cells are much smaller
    • Structural differences between prokaryotic and eukaryotic cells
      • Prokaryotic cells lack a true nucleus, have a single circular strand of DNA, and may contain small rings of DNA called plasmids. Eukaryotic cells have a true nucleus containing genetic material
    • Microscopes let us see things that we can't see with the naked eye. The microscopy techniques have evolved over the years with advancements in technology and knowledge
    • Types of microscopes
      • Light microscopes
      • Electron microscopes
    • Light microscopes use light and lenses to form an image of a specimen and magnify it. They allow us to see individual cells and large subcellular structures
    • Electron microscopes use electrons instead of light to form an image. They have higher magnification and resolution, allowing us to see smaller details like the internal structure of mitochondria and chloroplasts
    • Magnification formula: Magnification = Image size / Real size
    • You need to be able to use the formula for magnification to calculate the magnification of an image
    • Microscopes can see very small objects
    • Numbers can be written in standard form to manage very big or small numbers with lots of zeros
    • Writing numbers in standard form
      Move the decimal point left or right to represent a power of 10 (positive if left, negative if right)
    • When using a light microscope, a slide needs to be prepared by placing the specimen on it
    • Preparing a slide to view onion cells
      Add a drop of water to the middle of a clean slide, separate epidermal tissue, place tissue in water on the slide, add iodine solution, cover with a cover slip
    • Using a light microscope
      Clip the prepared slide onto the stage, select the lowest-powered objective lens, adjust focus with coarse and fine adjustment knobs, swap to higher-powered lens for greater magnification
    • Drawing observations under a microscope
      Use a pencil, draw neatly, take up at least half of the available space, do not include coloring or shading, draw in proportion, include a label and magnification
    • If a firm increases advertising, the demand curve shifts right, increasing the equilibrium price and quantity
    • Marginal utility is the additional satisfaction gained from consuming an additional product, and total utility is the sum of marginal utilities for each unit
    • When drawing cells, the cellular structures should be drawn in proportion
    • Remember to include a label of what you were observing and write down the magnification that it was observed under
    • Label the important features of your drawing
    • A light microscope is better than a heavy one
    • If you can use a microscope, you're halfway to ruling the world. That's what I like to think, anyway
    • Why might you add stain to the sample on a microscope slide?
    • Cells don't all look the same. They have different structures to suit their different functions
    • Cells Differentiate to Become Specialised
      1. Differentiation is the process by which a cell changes to become specialized for its job
      2. During differentiation, cells develop different subcellular structures and turn into different cell types
      3. This allows cells to carry out specific functions
      4. Most differentiation occurs as an organism develops
      5. In most animal cells, the ability to differentiate is lost at an early stage after they become specialized
      6. However, many plant cells retain the ability to differentiate
      7. Cells that differentiate in mammals are mainly used for forming and replacing cells, such as skin or blood cells
      8. Some cells remain undifferentiated and are called stem cells
    • Specialised Cells
      • Sperm Cells are specialized for reproduction
      • Nerve Cells are specialized for rapid signalling
      • Muscle Cells are specialized for contraction
      • Root Hair Cells are specialized for absorbing water and minerals
      • Phloem and Xylem Cells are specialized for transporting substances
    • Root hair cells are cells on the surface of plant roots, which grow into long "hairs" that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions from the soil
    • Phloem and Xylem cells form phloem and xylem tubes, which transport substances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem cells are hollow in the center and phloem cells have sieve plates for substances to flow through
    • Plants transport food substances from the leaves to growing parts of the plant through phloem tubes
    • Give one feature of a phloem cell that makes it specialized for its function
    • Describe how a root hair cell is specialized for its function
    • Chromosomes contain genetic information. Most cells in your body have a nucleus which contains your genetic material in the form of chromosomes. Each chromosome carries a large number of genes that control the development of different characteristics
    • Most cells in your body have a nucleus. The nucleus contains your genetic material in the form of chromosomes
    • Chromosomes
      Coiled up lengths of DNA molecules