Year 11 Biology Summaries PDF

Year 11 Biology Summaries Inquiry Questions: What distinguishes one cell from another? Prokaryotic Cells Eukaryotic Cells Technologies used to determine cell structure and function Drawing scale Diagram Different cell organelles and arrangemen...

Year 11 Biology Summaries Inquiry Questions: What distinguishes one cell from another? Prokaryotic Cells Eukaryotic Cells Technologies used to determine cell structure and function Drawing scale Diagram Different cell organelles and arrangements Fluid mosaic model Cell membrane Inquiry Questions: How do cells coordinate activities within their internal environment and the external environment Diffusion Osmosis Active transport Endocytosis Endocytosis Surface area to volume ratio Concentration gradients Cell requirements Forms of energy Removal of wastes Photosynthesis Cellular respiration Removal of cellular products and waste (Eukaryotic cells) Action of enzymes Environmental effects of enzyme activity Module one: Cells as the basis of life Cell structure - Organelles, their structure and function Organelles Structure & Function Mitochondria: The function of the mitochondria is to act as the powerhouse of the cell, as it is responsible for the production of adenosine triphosphate (ATP) through cellular respiration. The Structure of the mitochondria is a double membrane layer with an intermembrane space and matrix in the very inside, this allows more surface area for exchange and the synthesis of adenosine triphosphate. Outer Membrane: The outer membrane separates the intermembrane space from the cell's cytoplasm, this allows the internal membrane space to be regulated to best fit the functions of the mitochondria. The outer membrane is also responsible for the process of lipid synthesis. Intermembrane space: The intermembrane space is the space between the outer membrane and the inner membrane, mostly holding a protein called cytochrome C (Cyt C) used in the electron transport chain. The role of the intermembrane space is to regulate the respiration and metabolic functions of the mitochondria. Inner membrane: The inner membrane separates the intermembrane space for the matrix, made 75% of enzymes. The inner membrane holds the F1F0ATPase protein complex responsible for the electron transport chain, the Cristae: The cristae is the groves in the inner membrane, which allow the mitochondria to have a larger surface area for reactions, process, and the transport of materials across the inner membrane. Matrix: The matrix of the mitochondria holds mitochondrial DNA, ribosomes, and electrons. The matrix of the mitochondria is responsible for the citric acid cycle and the electron transport chain. Mitochondrial DNA: Nucleus: The function of the nucleus is to act as the cell's control centre, responsible for storing the genetic information of the cell, alongside the synthesis of ribosomes. The structure of the nucleus consists of a Nuclear envelope with pores containing a Nucleoplasm with a nucleolus and the cell’s DNA. The double layered structure of the nucleus allows the regulation of process and conditions within the nucleus. Golgi Complex: The function of the Golgi Apparatus is the transportation of proteins and the transport of the cell’s waste products to outside of the cell. The structure of the golgi apparatus is made of 6 - 8 cistern that are seen as a single organelles, to increase the available surface area to volume ratios. The higher surface area to volume ratio also faster transport of particles in and out. Ribosomes: The function of ribosomes is the translation of mRNA into amino acids chains for protein synthesis The structure of ribosomes is made of two subunits which hold the mRNA in place for the tRNA to translate that into the correct sequence of amino acids found in the cytoplasm. The smaller subunit holds the mRNA from the bottom and the larger subunit holds the tRNA in place as well. Rough endoplasmic reticulum The function of the Rough endoplasmic reticulum is to activity synthesis and export proteins to other parts of the cell. The structure of the rough endoplasmic reticulum (Rough ER) a network of membrane sacs and tubes that are embedded with ribosomes to synthesise proteins. Smooth endoplasmic reticulum The function of the smooth endoplasmic reticulum is the synthesis of molecules other proteins, such as the ones found in steroid secreting cells. The structure of the smooth endoplasmic reticulum is a network of tubes that are used to increase the surface area available for transport and synthesis of other molecules within the cell. Lysosome The function of the lysosomes is to act as the recycling units of the cells by digesting unwanted matter and transporting it out of the cell. The structure of the lysosomes is a membrane sac with a mini cytoplasm inside, which contains proteins to digest the unwanted matter Chloroplast The function of the chloroplast is to carry out photosynthesis, by trapping light energy to split water molecules, alongside processing DNA. The structure of the chloroplast is a double membrane capsule with layers of stacked membranes to absorb more light energy. Cytoplasm The function of the cytoplasm is to regulate the process and condition in the external environment of the cell. The structure of the cytoplasm is a liquid filled with proteins, organelles, ions, and salts. Vacuole The function of the vacuole is the storage of enzymes with other organic or inorganic molecules. The structure of the vacuole is a membrane bound space filled with liquid consisting of ions, and salts. Flagella The function of the flagella is mainly the movement of the cell via acting as a propeller on the back of the cell. The structure of the Flagella is embedded in the cell membrane surrounding the cell and uses a system of many different rotating parts to create a propelling motion of the tail/ hair-like structure. Prokaryotic & Eukaryotic cells Four Common Structures Cell membrane: All cells are surrounded by a cell membrane that separates the internal environment from the outside environment. Cytoplasm: Contain cytosol, made of water containing ions, salts, and organic molecules. DNA: Genetic material that carries hereditary information that directs the cell activities, which is passed from parents to offspring. Ribosomes: The organelles that are responsible for the synthesis of proteins. Prokaryotic Cells 4 common Structures Eukaryotic Cells Smaller Cell membrane Larger No membrane bound Ribosomes Membrane bound organelles. Genetic material organelles Loop DNA (DNA) Linear DNA Unicellular Only The Cytoplasm Unicellular or Can only reproduce multicellular sexually. Can reproduce Less complex Sexually or Asexually. More complex Prokaryotic Cells Prokaryotic cells are smaller and less complex cells that are only able to reproduce asexually, as their only unicellular. The structure of the prokaryotic cell is less complex, as they have no membrane bound organelles and have DNA in a loop. Prokaryotic cells are split into two domains of microscopic organisms; bacteria and archaea. Bacteria (Prokaryotes) Bacterial cells have diverse metabolic systems that allow them to carry out photosynthesis or chemosynthesis. Their also unique as they have cell walls that are made of peptidoglycan, which come in two types: Gram - Positive: A thick layer, which is purple. E.g Staphylococcus. Gram - Negative: A thin layer, which is pink. E.g Cyanobacterium. Archaea (Prokaryotes) Archaea cells have a membrane composed mainly of lipids that's able to stay selectively permeable over a wide range of temperatures. These features allow archaea cells to survive in very extreme environments. Eukaryotic Cells Eukaryotic cells are larger and more complex cells that can be single cellular or multicellular organisms. Eukaryotic cells are able to reproduce asexually and sexually. Eukaryotic cells are able to compartmentalise due to having membrane bound organelles, which allows them to be more efficient in reactions. Reactions can be faster in Eukaryotic cells as their different enzymes can be in their ideal conditions. This allows the Eukaryotic four main domains; plant, animal, fungus, and plastids to be less affected by their external environment. plant cells (Eukaryotes) Plant cells have a few unique features: a cell wall, chloroplasts, and larger vacuole.(10-100 um) Animal Cells (Eukaryotic) Animal cells have the unique structure of a peroxisome and have smaller vacuoles. Cell Movement Active & Passive Transport Passive transport is the movement of substances without the requirement of energy. E.g Substance such as water, oxygen, carbon dioxide and other small ions can freely move through the cell membrane Active transport is movement of substances that requires energy in the form of ATP, as substances move against the concentration gradient. This happens as proteins bind to molecules and carry them through the cell membrane, some proteins needing the activation of substrates to carry previously excluded molecules. Diffusion Diffusion is the movement of a solute or molecule from a region of higher concentration to a region of lower concentration. Diffusion can happen at the membrane as very small particles pass through the membrane from extracellular to the cytoplasm due to diffusion. Simple diffusion: Is the movement of substances across a membrane by passive transport from a region of higher concentration to a region of lower concentration, occurring because there is a concentration gradient. Facilitated diffusion: is movement of substances down the concentration gradient through the channel or Carrier proteins in the membrane. The use of channel proteins in diffusion allows faster movement and selective permeability, as proteins are specific for certain substances. There are some negative aspects of facilitated diffusion as the proteins can become saturated or full as the concentration increases and some substances can be inhibited by the presence of other substances using the same protein. Osmosis Osmosis is the net diffusion of a solvent (mostly water in biology) from a region of low concentration to a region of higher concentration through a selectively permeable membrane or semipermeable membrane. Endocytosis A type of active transport in which larger substances are transported across a membrane. The cell takes in substance by surrounding it with a membrane that infolds to enclose the substance, forming a vacuole or vesicle. Exocytosis A type of active transport where the substances are released from the cell when vesicles fuse with the membrane and unfold. The process of exocytosis is used to transport and remove waste or unwanted matter from the cell. Area to Volume Ratio The amount of area available for the amount of volume has a massive effect on the efficiency of the cell's diffusion. The area to volume ratio is important as it decides the materials the cells are able to take in and the amount of resources. As a cell increases in size the surface area to volume ratio decreases. There are three ways that cells increase the membrane surface area of the cell without changing the volume: Cell compartmentalisation: This creates more space for membrane bound enzymes to increase the activity of the cell. A flattened shape: increases the surface area to volume ratio allowing a higher rate of exchange through the membrane and less distance for substances transport. Cell membrane Extensions: An extension such as a microvilli that increases the amount of surface area by going off the membrane. Cell requirements Inorganic Compounds Water or H20: Important solvent and medium of transport for the cell. Water makes up 80% of the cell molecular composition or weight. Oxygen or O: Needed for energy supply. Carbon Dioxide or CO2: Is a source of Carbon for organic molecules. Nitrogen: The key atom is the amino acids, the building blocks of proteins. Organic Compounds Carbohydrates: Energy sources and support the structure of the cell. Lipids: Make up the cell membrane and energy storage. Proteins: Composed of amino acids and are enzymes that are part of the cell membrane. Nucleic acid: Carry genetic information of the cell. E.g RNA & DNA Energy Requirements ATP = Adenosine Triphosphate ATP is the universal carrier of energy. The bonds between the inorganic phosphate are high energy and can be broken to release that energy. ATP Cycle: Adenosine Diphosphate (ADP) is combined with a phosphate ion to form ATP molecules. Photosynthesis Respiration Removal of waste Enzymes Structure Function Module Two: Organization of Living things Organisation of cells Nutrient and gas requirements Transport Systems Module Three: Biological Diversity Environmental effects on organisms Adaptations Natural Selection Module Four: Ecosystem Dynamics Population Dynamics Past Ecosystems Future Ecosystems - Differences between Prokaryotic and Eukaryotic cells (including approximate size) Applying skills - Drawing scaled diagrams of cells - Comparing and contrasting cells and their organelles Cell movement - How substances move into and out of cells (diffusion, osmosis, active transport, passive transport, endocytosis, exocytosis) - What determines the form of movement (surface area to volume ratio, concentration gradients, characteristics of materials being exchanged Cell requirements - Energy, light and chemical - Matter, including gases, nutrients and ions - Removal of waste Enzymes - Their structure and function - The effect of the environment on their structure and function Nate Young - Year 11 Module 1 Cells as the Basis for Life Glossary