AOS1

• Eukaryotes

  • Single and multicellular
  • Has a nucleus
  • Linear strands of DNA
  • Membrane-bound organelles
• All cells come from pre-existing cells
• Prokaryotes

  • Single cellular
  • No nucleus
  • Circular loop of DNA
  • Not membrane-bound organelles
• Organelles

  • Structures in cells that perform specialised functions
• Small cells have a larger surface area to volume ratio
• All living things are made up of cells
• Cytoplasm is the cytosol and all organelles inside the plasma membrane, except the nucleus
• Cytoskeleton maintains cellular structure and integrity, transports vesicles around the cell
• Ribosomes are small RNA protein structures, they are the site of protein synthesis
• Chloroplasts conduct photosynthesis in plant cells
• Plasma membrane is composed of a phospholipid bilayer embedded with proteins, carbohydrates, and cholesterol
• Cells are the smallest and most basic unit of life
• Prokaryotes

  • Bacteria
  • Archaea
• Cytosol is the aqueous fluid inside a cell that surrounds the organelles
• Surface area to volume ratio is an important factor in the limitations of cell size and the need for internal compartments (organelles) with specific cellular functions
• Having a high surface area to volume ratio ensures organisms can exchange substances efficiently
• Mitochondria generate energy for animal cells in the form of ATP through aerobic cellular respiration
• Cell wall provides strength and structure to plant, bacterial, and fungal cells
• Membrane-bound organelles

  • Nucleus
  • Rough endoplasmic reticulum
  • Smooth endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Mitochondria
  • Chloroplast
  • Vacuoles
  • Vesicles
• Plasma membrane separates the extracellular environment from the intracellular environment
• Phospholipids are the main molecules of which membranes are composed
• Types of Eukaryotes

  • Animals
  • Plants
  • Fungi
• Active Transport

  1. Using membrane proteins to move molecules across a membrane against their concentration gradient

  2. Requires energy, typically in the form of adenosine triphosphate (ATP), and membrane proteins like protein pumps and carrier proteins
• Facilitated Diffusion

  1. Molecules move through a phospholipid bilayer with the help of a membrane protein

  2. Includes protein channels and carrier proteins
• Simple Diffusion

  1. Occurs when molecules move from an area of high concentration to an area of low concentration (down their concentration gradient)

  2. Polarity and size determine which molecules can freely diffuse across the plasma membrane
• Fluid Mosaic Model

  • Describes how the components of the membrane come together as a 'mosaic' to give the membrane a fluid character
  • Includes lipids, proteins, and carbohydrates
• Passive Transport

  Movement of molecules through a semipermeable membrane without an input of energy
• Permeability

  The ability of a substance to allow another substance to pass through it
• Osmosis

  The diffusion of water across a selectively permeable membrane from areas of low solute concentration to areas of high solute concentration
• Endocytosis

  Bulk transport of materials from outside to inside the cell via vesicles made of a phospholipid bilayer
• Bulk transport

  Using vesicles to move large molecules or groups of molecules into or out of the cell
• Exocytosis

  • Substances are transported out of the cell via vesicles that fuse with the plasma membrane
  • Commonly used to get rid of waste or transport proteins to where they need to go
• Binary fission is the process bacteria use to carry out cell division
• Active transport - process

  1. Binding – the molecule binds to a specific protein pump

  2. Conformational change – energy released from ATP causes a conformational change in the protein pump

  3. Release – the molecule is pushed through protein and released to the other side of the membrane
• Prokaryotic cells have one circular strand of DNA
• Binary fission involves DNA replication, elongation of the cell, migration of newly copied DNA, formation of septum, and cell wall formation
• The eukaryotic cell cycle includes interphase, mitosis, and cytokinesis
• Prokaryotes lack a nucleus, but DNA is floating in a structure called a nucleoid
• Interphase consists of resting phase (G0), cell growth (G1), DNA replication (S), and preparation for mitosis (G2)
• Mitosis includes prophase, metaphase, anaphase and telophase