Biology year 11 term 1

• Membrane-bound organelles in eukaryotic cells:

  • Nucleus: Holds DNA, controls cell activities
  • Endoplasmic Reticulum (ER): Synthesizes and transports proteins and lipids
  • Golgi Apparatus: Modifies and packages proteins and lipids
  • Mitochondria: Generates energy through cellular respiration
  • Chloroplasts (in plant cells): Converts sunlight into energy (photosynthesis)
• Prokaryotic cells:

  • Simple cells without a nucleus or membrane-bound organelles
  • Lack a true nucleus, genetic material in nucleoid
  • No membrane-bound organelles like mitochondria or ER
  • Generally smaller and structurally simpler
  • Example: Bacteria (e.g., Escherichia coli or E. coli)
• Eukaryotic cells:

  • Complex cells with a true nucleus and membrane-bound organelles
  • Have a nucleus containing genetic material (DNA)
  • Possess membrane-bound organelles with specific functions
  • Structurally more complex compared to prokaryotic cells
  • Examples: Plant cells (in plants), Animal cells (in animals), Fungi cells (in fungi)
• Similarities between prokaryotic and eukaryotic cells:

  • Both have a cell membrane enclosing the cell
  • Both have genetic material (DNA) for cell functions
  • Both perform basic life functions like growth, reproduction, and response to stimuli
• Differences between prokaryotic and eukaryotic cells:

  • Prokaryotic cells lack a true nucleus and membrane-bound organelles, while eukaryotic cells have both
  • Prokaryotic cells are generally smaller and simpler compared to eukaryotic cells
  • Eukaryotic cells are found in more complex organisms like plants, animals, fungi, and protists, while prokaryotic cells are mainly found in bacteria
• structure of a prokaryotic cell

  
• Eukaryotic cell structure

  
• Cytoplasm - contains various molecules such as proteins, carbohydrates, lipids, and water
• Mitochondria - produces energy through respiration
• Ribosomes - involved in protein synthesis
• Show cell organelles

  
• OCTOS ac

  
• Nucleus:

  • Contains DNA in the form of chromosomes
  • Considered the brain of the cell
• Nucleolus:

  • Inside the nucleus and is the manufacturing site of ribosomal RNA for protein synthesis
• Mitochondria:

  • Creates energy via respiration
  • Oval shaped structure with a double membrane and inner layer folded multiple times to increase surface area
  • Responsible for cellular respiration and often referred to as the 'powerhouse of the cell'
• Golgi apparatus:

  • Modifies lipids and proteins and processes materials to be excreted from the cell
  • Where proteins and fats (lipids) are altered
• Lysosome:

  • Contains enzymes needed to break down materials
  • Breaks down substances with enzymes
• Endoplasmic reticulum:

  • Large network of membranes throughout the cell involved in material transport
  • Rough ER has ribosomes for protein synthesis, smooth ER is the site for enzyme production
• Identify questions:

  • Function of mitochondria: Produces energy necessary for the cell's survival and functioning
  • Where the cell's DNA is stored: In the nucleus
• Explain questions:

  • Why animal cells have more mitochondria: Animal cells require more energy for mobility or mechanical movement, hence more mitochondria
  • Importance of endoplasmic reticulum for cell function: ER is crucial for material transport within the cell
• Create questions:

  • Factory analogy for cell parts:
  • Packer: Golgi apparatus
  • Conveyer Belt: Endoplasmic reticulum
  • Builder: Nucleolus
  • Electricity: Mitochondria
  • Security Guard: Cell membrane
• Passive transport:

  • Type of membrane transport not requiring energy to move substances across cell membranes
• Active transport:

  • Requires energy to move substances against a concentration or electrical gradient, similar to a canoeist paddling upstream
• Diffusion refers to the movement of particles from an area of high concentration to an area of low concentration
• Particles will randomly move around until they have evenly spread across the available space
• Equilibrium refers to the state when balance is reached
• Concentration Gradient:

  • The difference in concentration of a substance between two areas is called the concentration gradient
  • The bigger the difference, the steeper the concentration gradient and the faster the molecules of a substance will diffuse
• Factors that can affect the diffusion rate include:

  • Concentration gradient: The higher the concentration gradient, the faster the rate of diffusion. Diffusion particles move down a concentration gradient
  • Size of the molecule: The smaller the particle, the faster the rate of diffusion
  • Temperature: Particles at higher temperatures have more energy and move faster in hotter conditions
  • Diffusion distance: The further the distance the particle needs to travel, the slower the diffusion rate
  • Surface area: The greater the surface area, the higher the rate of diffusion
• • Permeability of particles: Depending on the permeability of a particle, it affects diffusion rate as some dissolve better than others, while some cannot pass through a semipermeable membrane at all
• Diffusion is a passive process of transport. It goes from a high concentration to a low concentration until the concentration is equal
• Mouse has a larger surface area compared to its volume
• Larger surface area allows nutrients/oxygen to enter and reach all parts of the cell
• Osmosis:

  • The movement of water molecules through a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration, driven by a concentration gradient
  • This process occurs passively, meaning it doesn’t require energy from the cell
• Osmosis is a type of diffusion. It refers to the movement of water molecules from an area of high concentration to an area of low concentration through a semi-permeable membrane
• When larger particles cannot diffuse, water molecules diffuse instead in order to achieve equal concentration
• The ultimate source of energy for life on Earth is the Sun through light energy, needed for photosynthesis
• Photosynthesis definition: Plants and some bacteria convert light into energy (glucose)
• Photosynthesis steps:

  • Light-dependent reactions: Light absorbed by chlorophyll in chloroplasts creates ATP and NADPH
  • Calvin Cycle: ATP and NADPH used to turn carbon dioxide into glucose in chloroplasts
• Photosynthesis importance: Produces oxygen and glucose, essential for life
• ATP is the source of energy for use and storage at the cellular level