Cells and Systems Biology Notes PDF

Unit 2 Cells and Systems Topic 1: Living Organisms  The protozoa is a one-celled organism. Q: What must this one cell do to stay alive? The eagle is a multi-celled organism. Q: What must this organism do to stay alive?  Functions and Structures ⚫Living organisms have...

Unit 2 Cells and Systems Topic 1: Living Organisms  The protozoa is a one-celled organism. Q: What must this one cell do to stay alive? The eagle is a multi-celled organism. Q: What must this organism do to stay alive?  Functions and Structures ⚫Living organisms have different structures to carry out functions to ensure their survival. ⚫6 Characteristics of all living organisms ⮚ made up of cells ⮚ need energy ⮚ grow ⮚ respond and adapt to their environment ⮚ reproduce ⮚ produce wastes  BIOLOGY - Living or Non-living? Organization - Living organisms are made of cells. The cell is: - Basic unit of every living system - The smallest thing considered to be alive - Can perform all the processes that allow life to happen All organisms are made up of at least one cell.  Spontaneous generation? ⚫Every cell comes from another cell – not by spontaneous generation as proven by Francesco Redi  BIOLOGY - Living or Non-living? Energy: Living organisms need energy. - The ability to make things move and change - Is obtained from the environment. - Plants and animals differ in how they obtain their energy. - Plants use the energy of the sun to make their own food. - Animals get their food from the environment around them. Nutrients: substances that provide the energy and materials that organisms need to grow, develop, and reproduce. All of the processes that occur inside the organism to sustain its life are called the organism’s metabolism.  BIOLOGY - Living or Non-living? Growth - Living organisms grow and develop. - Organisms have the ability to replace some cells that are worn out or damaged. As organisms grow and develop their body size and shape can change. This is called development.  BIOLOGY - Living or Non-living? Environment - Living organisms adapt and respond to their environment. An adaptation: a characteristic that allows an organism to survive in its environment Organisms adapt to their environment for survival. Two types of adaptations: - structural – organisms have a structural feature that enables them to adapt - behavioral – an action the organism engages to survive A stimulus is anything that causes a response in an organism. The organism’s reaction to this stimulus is called a response.  BIOLOGY - Living or Non-living? Reproduction - Living organisms reproduce. - All living things come from other living things. Reproduction is not necessary for the organism to survive (because it will eventually die), but it is necessary for the species to survive. Wastes - Living organisms produce wastes. - All living things produce waste in different states (solid, liquid and gas). Wastes must be eliminated from the organism because they are toxic.  BIOLOGY - Structures and Functions Structures - Organisms developed different structures (body parts) to perform tasks that keep them alive - They have different functions. e.g. Spiracles are holes on the sides of the abdomen on some insects to allow for gas exchange. Insect can adjust the size of the spiracle to control the amount of air entering their body.  BIOLOGY - Structures and Functions Functions: All organisms have built-in structures that perform certain tasks or functions to stay alive. Tasks may include: - Gathering and Processing Nourishment - Generating and Exchanging Waste - Responding to Internal and External Stimuli - Adaptation - Protection - Reproduction - Movement (Locomotion)  BIOLOGY - Structures and Functions Different Structures For Similar Functions Different plants and animals have developed different structures for performing similar functions. Function Plant Animal claws, hands, food/nutrient roots tentacles. gathering mouths, tongues gills, lungs, skin, breathing leaves, needles spiracles plant usually do not locomotion move from place to fins, legs, tails, wings place BIOLOGY - Structures and Functions Different Structures For Similar Functions Charles Darwin: - Observed similarity in structure with some variability amongst animals living in the Galapagos Islands. - Wrote ‘Origin of the Species’; a result of his observations of many of the animals on the Galapagos Islands.  BIOLOGY - Structures and Functions - Darwin’s closely related species of finches have different bill structures to perform the function of gathering food.  Levels of Organization Living Organisms – are made up of Systems – which are made of Organs – which are made of Tissues – which are made of Cells  Cells and Systems Unit 2 Topic 2: Microscopes and Cells  After this topic…I can ⚫ Describe the historical development of the microscope ⚫ Properly and safely use a light microscope ⚫ Prepare a wet mount ⚫ View samples under the microscope and draw what is seen ⚫ Calculate magnification and field of view  Magnification - Magnification: the process of enlarging an object - Microscope: an optical instrument that uses a lens or a combination of lenses to produce magnified images of small objects, especially of objects too small to be seen by the unaided eye.  Early Microscopes - Interest in microscopes began as early as the 17th century - Anton van Leeuwenhoek (Holland) built 250 microscopes and studied blood and stuff he scraped of his teeth - He called the tiny, single-celled organisms he saw ‘animalcules’  Early Microscopes - In 1660 the English scientist Robert Hooke used the term ‘cellulae’ now called cells to describe the honeycomb- like structure of cork - He published a book called ‘Micrographia’ illustrating a variety of cells and other microscopic objects  Early Microscopes - Schleiden, Schwann and 2 Key Points of Cell Theory Virchow all hypothesized - All living things are that all organisms were composed of one or more composed of cells cells - Cells are the basic units of - They suggested the cell was structure and function in all the basic unit of life and organisms formulated the cell theory  Microscopes Today … Microscopes come in many shapes and sizes. Technology improvements have lead to the development of compound light microscopes (2000X magnification) and electron microscopes (2,000,000X magnification).  Microscopes Today The (Compound) Light Microscope - Have two lenses to increase the power of magnification - Can magnify objects 2000x - Still not strong enough to see smaller components of cells or viruses  Light/Optical Microscopes Compound or Bright-field Microscope - Simplest illumination by transmitted white light (i.e., illuminated from below and observed from above) - Image is a dark sample on a bright back ground  Light/Optical Microscopes Stereo Microscope - dissecting microscope - variant optical microscope designed for low magnification observation of a sample, typically using light reflected through the surface of an object rather than transmitted through it  Light/Optical Microscopes Phase contrast microscope - transparent cells can be observed without staining - cell division and other biological processes can be observed in a living state - based on phase change of light when it passes through materials - the phase contrast can be converted into brightness differences Phase Bright  Microscopes Today There are two types of electron microscopes - TEM (transmission electron microscope) - SEM (scanning electron microscope) - The microscope has become a valuable tool for the investigation of the microscopic world. - Fiber optics is a technology that allows light to travel down a flexible tube. Medical researchers now use fiber optics to create microscopes that can be used to see inside the body and to assist in locating operating regions that help surgeons do their work more effectively.  Electron Microscopes The Transmission Electron Microscope - A beam of electrons is transmitted through specimen - An image is formed from the interaction of the Kidney TEM electrons with the sample micrograph as the beam is transmitted through the specimen.  Electron Microscopes The Scanning Electron Microscope - Uses beams of electrons instead of light - Images a sample by scanning the surface with a focused beam of electrons - Can magnify over 2 000 000x  Microscopes Today Fluorescent Microscope ◦ Uses a high intensity light (near infrared) to excite a dye on the specimen ◦ Certain parts of the cell can be tagged with a fluorescent dye and these glow under the microscope  Parts of a Compound Light Microscope ⚫ Use page 106 and 107 in textbook to label the parts of the compound light microscope. ⚫ Write a description of the function of each part.  Calculating Magnification - A magnifying lens that - To calculate the total magnifies the size of an magnification of a compound image by ten times has a microscope, multiply the magnification of 10x magnification of the ocular lens - A compound microscope, like by the magnification of the the ones in your classroom, objective lens. uses two lenses – an ocular lens and an objective lens. Example: - Combining two lenses creates - Ocular lens = 10x higher magnifications. - Objective lens = 4x - Total magnification = 10x x 4x = 40x  Calculating Field of View (p 110 – 111) ⚫ The field of view is the area that is visible in an optical instrument. ⚫ Knowing this allows you to develop the relative size of objects and provides quantitative data on microscopic objects. ⚫ Field of View Formula ⚫ e.g.: Your low-power objective lens is a 4x lens with a field of view of 4 mm, and your medium-power objective lens is a 10x lens. So your medium power field of view is: _________________  Preparing a Slide as a Wet Mount ⚫p 112 – 113  Cells and Systems The Cell and Its Structure The Wacky History of Cell Theor y 6:11  BIOLOGY - Cells Cells - Building Blocks of Living Things A cell is - the basic unit of life - all the functions carried out by living things are carried out by their individual cells Scientists, Matthias Schleiden and Theodor Schwann studied cells combined their observations to conceive a hypothesis … all living things are made up of cells. Rudolf Virchow contributed his observation and together they formulated the cell theory.  BIOLOGY - Cells Cell Theory - three main ideas: All organisms are composed of one or more cells. The cell is the basic unit of organization of organisms. All cells come from pre-existing cells.  BIOLOGY - Cells All cells Microscopic cells have structures to perform various functions for survival need a constant supply of materials (oxygen, water and food) to provide energy to carry out the work need to get rid of waste products What do you notice?  BIOLOGY - Cells Two different cell classifications: Prokaryotic cells – Eukaryotic cells – cells with unicellular organisms, membrane-bound organelles without a true nucleus – (structure that performs DNA found free in specific function in a cell) cytoplasm  BIOLOGY - Cell Structures Structures inside a cell are called organelles. Cell - surrounds & protects the contents of the cell Membran (looks like a thin line surrounding the cell) e ’Controlle d Gateway’ Cell Wall - thicker & more rigid than membranes, ’Frame’ providing support for the plant or fungi (a rigid frame-like covering that surrounds the cell membrane) Cytoplas - distributes materials to different parts of the m cell, gel-like ’Kitchen’ (a liquid inside the cell, which has grainy- looking bits in it)  BIOLOGY - Cell Structures Structures inside a cell are called organelles. Nucleus - controls the cell’s activities ’Command (a fairly large, dark, spherical structure Center’ that’s usually near the center of the cell) Vacuoles - is a membrane-bound sac acting as a ’Storage storage space for surplus food, wastes and L i Rooms’ other substances the plant cell is unable k n to use immediately (clear, liquid-filled spaces in various places within the cytoplasm) Chloroplas - are the structures in which photosynthesis ts takes place (greenish structures found ’Solar only in a plant cell) Panels’  BIOLOGY - Cell Structures Structures inside a cell are called organelles. Mitochondr - chemical reactions occur here that ia convert energy into useable forms ’Powerhouse’ (small circular structure with little stringy bits inside)  BIOLOGY - Cell Structures Other organelles Endoplasmic reticulum: interconnected membranous sacs ⮚ Smooth e.r. – many enzymes are attached; helps with protein folding and transport of synthesized proteins ⮚ Rough e.r. - ribosomes are attached; produces proteins Ribosomes: small bodies either free or attached to endoplasmic reticulum; site of protein synthesis Golgi apparatus: sorts and packages macromolecules for delivery to other organelles Lysosomes: in animal cells, round membrane; breaks down larger food i L particles into smaller, digests old cell parts n k Lysos omes in an imal cells  BIOLOGY - Plant Organization Plant Cell Nuclear Envelope? Is it radio active? plasma/cell membrane Vacuole  BIOLOGY - Animal Cell Organization Animal Cell Lysosom e Cili a  BIOLOGY - Cell Organization Unicellular Organisms Single-celled organisms can perform all of the functions needed for survival within the confines of its individual cellular interior. Amoeba are common unicellular organisms that live in water. They move around using foot-like projections called pseudopods (false feet). They extend a pseudopod and the cytoplasm fills it. They also use their pseudopods to capture food by surrounding it between two pseudopods and absorbing it. Paramecium move swiftly through the freshwater where they live. They are covered in hair-like structures called cilia, which move back and forth like little oars, moving it through the water. Cilia also help gather food, by channeling the food to an oral groove, which is also lined with cilia, sweeping the food into the cytoplasm forming a food vacuole.  BIOLOGY - Cell Organization Unicellular or Multi-cellular Organisms? Multi-cellular organisms can: - live in a wide variety of environments - grow very large - obtain their energy from a wide variety of foods - have complex bodies - specialize functions and work in harmony with other cells  BIOLOGY - Cells Cell Size Materials (O2, H2O, food, wastes) must pass through the cell membrane Large cells need more materials, produce more waste products ∴very narrow range of size between 10 - 50 µm (micrometers) Cell Size and Scale L ink l i n k  BIOLOGY - Cell Processes The Cell Membrane A cell membrane allows some substances to enter or leave the cell, while stopping other substances. It is a selectively permeable membrane. (A permeable membrane allows all materials through, while an impermeable membrane does not allow anything through)  BIOLOGY - Cell Processes Diffusion The structure of the cell membrane controls what moves in or out of a cell. Particles - moving in all directions, bumping into each other, eventually spread out evenly throughout the cell (diffusion). Diffusion plays a part in moving substances into and out of a cell.  BIOLOGY - Cell Processes Concentration determines the direction that a substance takes through the cell membrane – particles move from higher concentration areas to lower concentration areas (equal concentration allows the movement of particles in and out equally – whereas, a higher concentration of particles on the inside of the cell will move to an area of lower concentration on the outside (so movement will only occur from inside to outside) – until there is a balance.