Brooks Biological Principles Exam 2 Questions and Correct Answers, Solution Guide 2024 Complete.

Brooks Biological Principles Exam 2 Questions and Correct Answers, Solution Guide 2024 Complete. Cytology the study of cells Cell Theory all living things are composed of cells and come from living cells Robert Hooke one of the first to use microscope, observing a piece of cork from the stem of plants, where he found chambers arising in the idea of a cell. Light Microscope takes pictures of large atoms. nucleus, not electrons Scanning Electron Microscope electrons are reflected off of a specimen and are analyzed by a computer to create a 3D image Transmission Electron Microscope Microtome: a tool used to cut extremely thin slices of material for observation under a TEM. Microtomes are often made of diamonds Can you see electrons using the electron microscopes? No, can only see neutrons & protons Why are most cells small? To maximize the ratio of surface area to volume for regulating the internal cell environment Smaller cells have bigger membranes Does cell need a bigger surface area or volume? surface area Plasma Membrane aka "Fluid Mosaic Model" composed of fluidlike phospholipid bilayer, proteins, cholesterol (helps maintain proper fluid viscosity), and glycoproteins (antigens: "name tags" for immune system) "self" antigen: produced by the body "not self" antigen: not produced by the body so antigens will attack this Get sick more when younger because body is still learning these "name tags" Arthritis: autoimmune disease where the body attacks itself Pollen grain: not self, antigens will attack = phagocytosis involved in ATP production and the electron transport system Cell Wall outside of the cell membrane in some organisms (plants); composed of carbohydrates or carbohydrate derivatives (peptidoglycan for bacteria) Cytoplasm material outside the nucleus • site for metabolic activity • cytosol: solution with dissolved substances such as glucose, CO2, & O2, etc • organelles: membrane-bound subunits of cells with specialized functions Cytoskeleton supportive and metabolic structure composed of microtubules (biggest, tubular dimers), microfilaments (smallest, actin), and intermediate filaments Microtubules form cilia (numerous & short) , flagella ( long, usually 1 or 2) , & centrioles Prokaryotes have a simple cellular organization with no nucleus or other membrane-bound organelles • nucleoid w/ DNA in continuous loop • 360 flagella rotation • ribosomes present • plasma membrane produces ATP • cell wall Ex: Bacteria & Archaea Eukaryotes have a complex cellular organization; membrane-bound organelles, located inside the cell membrane Nucleus contains the dna in form of chromosomes; control cellular activities via gene Nucleolus located in the nucleus, the site for ribosome synthesis Rough ER has ribosomes, necessary for protein synthesis Smooth ER no ribosomes, involve in lipids synthesis Golgi Apparatus packaging center for molecules; synthesizes carbohydrates Lysosome contains hydrolytic enzymes for intracellular digestion Peroxisome involved in hydrogen peroxide synthesis and degradation Chloroplast site of photosynthesis Chromoplast contains nongreen pigments Leukoplast stores starch Mitochondria produces ATP, aerobic mitochondria have their own DNA and mitochondrial DNA doesn't change as much, showing a clearer view of phylogeny DNA is more similar to bacteria, than DNA found in our nucleus (due to the endosymbiotic hypothesis, that life arose from prokaryotes) all of our mitochondria comes from our mothers Vacuole storage and space-filling structure Absolute 0 a theory that when there is no molecular motion at 0 K. contradicts "everything must have energy" Passive Transport relies on the thermal energy of matter; the cells do not do the work 3 Types of Passive Transport 1. Simple Diffusion 2. Facilitated Diffusion 3. Osmosis Diffusion Passive Transport movement from an area of high concentration to one of low concentration generally lipids and small charged particles lipids cross the membrane easily between the phospholipids without needing a protein to help them cross End result of simple diffusion is random dispersement, reaching an equilibrium Facilitated Diffusion Passive Transport a permease, or membrane enzyme, carries a substance • Channel proteins: proteins that create a hydrophilic core through which ions diffuse • Carrier proteins: change shape in response to a solute entering the protein, allowing the solute to be released on the other side of the membrane Ex: aquaporin- facilitates the diffusion of water Osmosis Passive Transport •facilitated diffusion across a semi-permeable membrane •movement of water from a hypotonic environment to a hypertonic environment (however the amount of water molecules on each side is the same) •Solute does not cross the membrane Osmotic Pressure The pressure of water wanting to move to the other side Causes the height of the water in the compartment containing the sugar to rise, due to the movement of pure water from the compartment without sugar to the compartment containing sugar water This process will stop once the pressure of the water and sugar water are equated Cell sap: attracts water Turgor Pressure Pushes the plasma membrane against the cell wall of the plant Caused by osmotic flow of water from area of low solute concentration (hypotonic) outside of the cell into the cell's vacuole, which has a higher solute concentration (hypertonic) Healthy plant cells are turgid and plants rely on turgidity to maintain rigidness Ex: Wilting: becomes limp through heat, loss of water or disease; to droop & Plasmolysis: the process in which plants lose water in a hypertonic solution (aka crenation) Turgid When a plant cell is in a hypotonic solution, the vacuole swells The presence of a cell wall prevents the membrane from bursting Bulk Flow a mass movement of fluid affected by pressure and solutes, Ex: Trees When it rains, what happens to the vacuoles of plant cells? the water goes towards the solutes in the vacuole and fill up the cell wall Tonicity Comparison of solute concentrations of 2 or more solutions A measure of osmotic pressure gradient of two solutions separated by a semipermeable membrane Influenced only by solutes that cannot cross the membrane, as only these exert an osmotic pressure 3 Classifications of Tonicity 1. Hypotonic 2. Hypertonic 3. Isotonic Hypotonic A solution with a lower concentration of solute in its surroundings, so in an attempt to balance concentrations, water will rush into the cell causing swelling Pure water is most likely to be hypotonic Hypertonic A solution with a higher concentration of solute on the outside of the cell When a cell is immersed into a hypertonic solution, the tendency is for the water to flow out of the cell in order to balance the concentration of the solute Isotonic A solution with the same solute concentration; Water molecules diffuse through the plasma membrane in both directions, and as the rate of water diffusion is the same in each direction, cells will neither gain nor lose water The best way to describe a solution with 50% solute and 50% solvent is a 50% solution What would happen if you were in a swimming pool for eight hours? you will gain weight because the water is hypotonic Salt water fish more water will enter the fish to reach equilibrium than fresh water fishes with a 1% tonicity How do salt water birds excrete salt from their bodies? through their eyes, forming a crust Blood cells in DI water will explode cause water is hypotonic Crenation aka Plasmolysis the process in which cells lose water in a hypertonic solution so they shrivel up Causes plants to wilt Cytolysis aka Hemolysis occurs when a cell bursts due to excess water in a hypotonic solution