Biology PDF Notes - Cells and Tissues

Cells December 8, 2024 4:48 PM Cells: - Move - Grow - Respire - Excrete waste - Obtain energy Cell size - Cells are generally similar in size - As size increases, volume increases rapidly When cells become too large they must divide...

Cells December 8, 2024 4:48 PM Cells: - Move - Grow - Respire - Excrete waste - Obtain energy Cell size - Cells are generally similar in size - As size increases, volume increases rapidly When cells become too large they must divide Biology Page 1 Unicellular and Multicellular December 8, 2024 4:54 PM Unicellular - Lower life forms - Often found in extreme conditions - Each cell must perform all life functions - Examples: Paramecium, Bacteria Multicellular - Cells are specialized - Groups of cells perform specific tasks - Examples: plants, animals Biology Page 2 Prokaryotes December 8, 2024 4:56 PM - Small and simple - Nucleoid (no nucleus) - Mostly unicellular - No membrane bound organelles - Cell walls - Material floats in cytoplasm - Examples: Bacteria, cyanobacteria (blue-green algae) Biology Page 3 Eukaryotes December 8, 2024 4:58 PM - Cytoskeleton - Complex - Nucleus - Membrane-bound organelles - Unicellular or multicellular - Examples: Plant and animal cells, fungi, protozoa (unicellular) Biology Page 4 Cell parts December 8, 2024 5:00 PM Biology Page 5 Cell Membrane - Security fence of the cell - Cell is surrounded by a flexible double layered cell membrane - Function is to both support the cell and allow some substances to enter while keeping others out - Semi-permeable membrane (only allows certain things to pass through) Cell wall - Only in plant cells - Give cell rigid structure and protects it from physical injury - Outside of membrane Chloroplasts - Only in plant cells - Found in cytoplasm - Give green color to plants - Primary food factory - Cause photosynthesis - Absorb light energy for photosynthesis - CO2+H2O = glucose + Oxygen Plastids - Only found in plants - Some store food or pigments - Some convert light energy to chemical energy in the form of organic compounds Vacuole - Warehouse of the cell (storage) - Plants only have one large one that takes up most of the space in the cell - When full of water, turgor pressure keeps cells plump which keeps the plant's stems and leaves firm Nucleus - Control room of the cell - Large control centre of a cell - Chromosomes (contain DNA), are stored in here - Separated from rest of cell by the nuclear membrane Biology Page 6 DNA - Factory manager of the cell - Chromatin is a thread-like material inside the nucleus - Contains genetic info called DNA, a substance that chromosomes are composed of (makes up genetic code) Mitochondria - Power generators of the cell - Powerhouse of the cell - Provide cell with energy from glucose, through a process called cellular respiration Endoplasmic reticulum - Production line of the cell - Three-dimensional network of branching tubes and pockets - Extends throughout cytoplasm from nuclear membrane - Transports materials such as proteins through the cell - 2 types: Smooth (SER) (no ribosomes attaches, makes fats or lipids), Rough endoplasmic reticulum (RER) (Has ribosomes attached, helps make proteins) Ribosomes - Assembly line of the cell - Found on the endo-plasmic reticulum or free in the cytoplasm - Make proteins Golgi bodies/apparatus - Shipping department of the cell - Collect and process materials to be removed from the cell - Also make and secrete mucus - Cells that secrete a lot of mucus have a lot of golgi bodies Cytoplasm - Factory interior of the cell - All the organelles inside the cell are suspended in the cytoplasm - Mostly water, but also contains other substances that the cell stores until they are needed - Many chemical reactions take place within the cytoplasm Cytoskeleton - Network of protein fibers supporting cell shape and anchoring organelles - Can stretch and contract to move cell parts as needed Lysosomes - Custodians of the cell - Contain proteins that break down food into smaller particles that the rest of the cell can use - Destroy old cells, recycle the parts - Destroy invaders Vesicles - Items to be shipped in the cell - Cellular package containing products such as proteins Biology Page 7 Diffusion January 7, 2025 10:09 AM - A process of moving substances across the cell membrane - Depends on the concentration of the substance on both sides of the membrane Diffusion - Movement of particles from an area of high concentration to lower concentration to equalize the concentration Osmosis - Movement of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration - The diffusion of water across a membrane Biology Page 8 Mitosis January 6, 2025 6:43 PM Multicellular Organism - An organism made up of more than one cell - Cells undergo division for growth, repair, and reproduction Growth - They grow by increasing their number of cells through cell division - As organisms grow they need to produce many more cells - Humans start from a single cell, and then end up with 50 to 75 trillion cells Repair - New cells are made through cell division - Dead or damaged cells need to be replaced - Every second we shed millions of cells in our intestine and from the surface of our skin - On average we replace every cell in our body every 7 years (excluding nerve and cardiac cells) Reproduction - Through cell division Asexual reproduction - Process of producing from only one parent - Offspring are genetically identical to the parent - Examples: Single celled organisms, some multicellular organisms Sexual Reproduction - Process of producing offspring by fusion of sex cells from two parents - Offspring get half their genetic info from each parent - Examples: Most multicellular organisms Cell Division - Hair, skin, fingernails, taste buds, and the stomach's protective lining are replaced constantly and at a rapid rate throughout our lives - Brain and nerve cells are not produced after we are a few months old (cell loss is usually permanent) - Liver cells rarely divide, but if there is injury to the liver and the liver is somehow reduced, liver cells will divide to get the liver back to the right size Chromosomes and DNA - Almost everything in a cell is controlled by the cells DNA (Deoxyribonucleic acid) - DNA is located in the nucleus of a cells and contains all of the cell's genetic info - DNA molecules are strung together in long strands called chromosomes - Humans have 46 chromosomes (23 pairs, on in each pair from each parent) The Cell Cycle - Two major phases in the cell cycle (interphase and mitosis) - Interphase: Cells go through a series of phases which allows the cell to grow, duplicate its DNA, and prepare for mitosis - Mitosis: cell divides and one cell becomes two cells Interphase - 3 parts (G1, S, and G2) - G1: cells grow (need to get big enough to undergo mitosis, if the cell is not big enough the daughter cells die) Biology Page 9  daughter cells die) - S: cells replicate all of their DNA so that they have 2 copies (so at the end of mitosis, each daughter cell has a complete copy of all the genes) - G2: Cells get ready to go through mitosis and divide - During interphase the cell carries out normal life functions (grows, make proteins, perform cellular respiration, moves, does any specialized functions it has) - During interphase the DNA is in long, spaghetti-like strands called chromatin Mitosis - At the end of interphase cells enter mitosis - Purpose: One parent cell produces 2 genetically identical daughter cells - Mitosis is the division of the genome/nucleus (physical division of the cell into 2 daughter cells is called cytokinesis and comes after mitosis) - After mitosis and cytokinesis is done, cells either become quiescent (inactive) or enter interphase again - Mitosis takes about 80 minutes for most eukaryotic cells Phases of Mitosis - PMAT (Prophase, Metaphase, Anaphase, Telophase) Prophase - Chromatin in the nucleus condenses into thick coiled structures called chromosomes - At this point there are 2 copies of each chromosome - Each chromosome contains 2 copies, called sister chromatids - The chromatids are held together by a centromere Metaphase - Chromosomes line up along the centre of the cell - They are moved there by the spindle fibres (which attach to the centromere) Anaphase - The centromere in the middle of the chromosome breaks - Sister chromatids are pulled to opposite sides/poles of the cell by the spindle fibres Telophase - Chromosomes/chromatids begin to unwind back to chromatin - Nuclear membrane begins to reform to make two new nuclei in the same parent cell Biology Page 10 Cytokinesis January 6, 2025 7:21 PM - The division of the cytoplasm to create 2 new daughter cells - In animal cells cytokinesis happens when the plasma membrane pinches until two cells are formed Plant cells - A cell plate forms between the 2 nuclei, separating them and creating two new cells Biology Page 11 Microscope January 7, 2025 10:06 AM How a microscope works - Ocular Lens: Magnifies image (usually 10x) - Objective Lens: Gathers light, magnifies (4x, 10x, 40x), and focuses image inside body tube - Body tube: image focuses - Bending light: the objective (bottom) convex lens magnifies and focuses (bends) the image inside the body tube and the ocular convex (top) lens of a microscope magnifies it (again) Parts of a light microscope - Light source: Could be a mirror, but most likely it is a bulb built into the base - Diaphragm: Adjusts the amount of light striking an object - Objective lens: Gathers light and magnifies image - Ocular lens (eyepiece): magnifies objects and focuses light to your eye - Stage: Holds slide in place (can be moved using the coarse or fine adjustment knob to bring the object into focus) - Base and arm: Structural support for the microscope Resolution: the ability to distinguish between 2 objects that are very close together - Light microscopes are limited by their resolution, and cannot produce clear images of objects smaller than 0.2 micrometres - Electron microscopes use beams of electrons to produce images (can view objects as small as the diameter of an atom Electron microscopes - Specimens from electron microscopy must be preserved and dehydrated (living cells cannot be viewed) - Transmission electron microscopes (TEMs) pass a beam of electron through a thin specimen - Scanning electron microscopes (SEMs) scan a beam of electrons over the surface of a specimen Field of View - Whole circular area that you see when you look through the microscope Biology Page 12  - Whole circular area that you see when you look through the microscope Magnification - To determine your magnification, multiply the ocular lens by the objective lens - Ocular 10x, Objective 40x: 10x40 = 400 Total Magnification - Ocular lens (10x) times the objective lens Field Diameter - Distance across the field of view - If you find field diameter on a low power magnification, you can use this to calculate the field diameter at higher magnifications - High power field diameter/low power field diameter = low power magnification/high power magnification - Low power (40x) = 4.5mm = 4500 micrometres - Medium power (100x) = 1.8 mm = 1800 micrometres - High power (400x) = 0.45 mm = 450 micrometres Calculating estimated actual size of a specimen - Actual size = field diameter/# of specimens fitting across field diameter - Field diameter: determine by evaluating which objective lens was used to view specimen - # of specimens fitting across field diameter: estimate how many specimens fit across the field diameter width wise Calculating magnification of a drawing - Magnification of drawing = width of drawing/actual size of specimen - Width of drawing: Use a ruler to measure and convert your units to micrometres Biology Page 13 Specialized Cells January 7, 2025 9:47 AM Regeneration - the process in which a body part is replaced or regrown - The human liver is the only human organ that has an ability to regenerate Process of Cell specialization - All cells in an organism contain the same DNA but are not all alike - Cell specialization: Cells develop in different ways to perform particular functions Animal cell examples - Lung cells, skin cells, or brain cells Plant cell examples - Xylem or phloem in the root, stem, or leaf Stem Cells - Every cell in your body originally came from a small group of stem cells - A stem cell is an unspecialized cell that can form specialized cells when exposed to the proper environment conditions, or they can remain unspecialized and actively dividing for long periods - Stem cells may be used to treat injuries, diseases, and regenerate organs - Stem cells are capable of becoming any cell, including nerve, blood, and muscle cells in the human body - Adult stem cells from the tissue of one organ can regenerate tissue in another organ Embryonic Adult Stem Cells - There are two types of stem cells: embryonic and adult - Embryonic stem cells are found in embryos - Embryonic stem cells are able to undergo differentiation - Specialized cells look different from one another and perform different functions - As these cells divide, further specialization occurs, leaving cells with a limited ability to create a variety of cell types (these are called adult stem cells) Potency definitions Potency: The potential to differentiate into different cell types - Pluripotent: Embryonic stem cells originate as inner mas cells within a blastocyst. The stem cells can become any tissue in the body, except for a placenta - Simple: Can divide into almost all cell types in an organism, but cannot develop into an entire organism on their own - Descendants of totipotent cells - Totipotent/omnipotent: Can differentiate into embryonic and extraembryonic cell types. These cells can construct a complete, viable organism. They are produced from the fusion of a egg and sperm cell - Simple: Can divide into all cell types in an organism, and has the potential to divide until it creates an entire, complete organism Meristematic Cells - Are plant stem cells - Found in the growing tips of roots and stems and also in a layer in the stem called the cambium Biology Page 14 Biology Page 15 Specialized Cells 2 January 8, 2025 11:36 AM Hierarchy of an Animal - Simplest level of organization (bottom) to most complex (top) - Organism > Organ system > Organs > Tissues > Cells > Molecules > Atoms Tissues - Groups of Similar cells that share the same specialized structure and function - 4 types of animal tissues: connective, epithelial, muscle, nervous Epithelial tissues - main purpose is to protect the organism from dehydration while also providing a resistance to friction - Cover surfaces such as skin and lining of internal organs Connective tissue - Main purpose is to provide support and insulation - Held together by a liquid, solid, or gel, known as a matrix - In fibrous connective tissue, cells are scattered among collagen fibres they secreted - In bone and cartilage, cells are scattered throughout the hard and pliable matrix Blood cells - Blood cells move through the body as a fluid matrix - Red blood cells contain hemoglobin, a protein that can absorb and release O2 - White blood cells protect the body from bacteria and viruses and fight infection - Platelets are cells that help in the process of blood clotting Muscle Tissue - Main purpose is to allow for the body to move - Made of long, thing fibers that contain specialized proteins that can shorten or contract - Three types of muscle tissue: skeletal, smooth, and cardiac - Skeletal: large, multinucleate (more than one nucleus) and column shaped sells (mainly attached to the skeleton) - Smooth: small and mononucleate (one nucleus), found in the walls of tubes such as blood vessels, glandular ducts, and the digestive system - Cardiac: small, striated, and branched Nervous tissue - Main purpose is to provide sensory sensations - These sensations allow for communication with the brain which allow for the coordination of body functions (including reactions - Thin cells with fine branches - Capable of conducting electrical impulses - Consists of neurons that transmit impulses - Cells act as supportive connective tissue in the brain and spinal cord Organs - A combination of several types of tissues working together to perform a specific function Organ system - A system in which one or more organs and structures work together to perform a major vital body function such as digestion or circulation Biology Page 16 Plant Tissues - All 4 types of plant tissue are grown from groups of meristematic cells known as meristematic tissue - Epidermal, Vascular, Ground, and Meristematic Epidermal Tissue - Found on both top and underside of the leaf and is clear and very thin - Specialized guard cells form a tiny opening called a stomate that allows carbon dioxide, water vapour and oxygen to move into or out of the leaf easily (mainly found on the underside of the leaf) Vascular Tissue - Plays an important role in transporting water and nutrients throughout the plant - Two types: Xylem and Phloem - Xylem: responsible for the movement of water and minerals from the roots up the stem to the leaves, where these substances can be used in photosynthesis - Phloem: transports the sugar produced during photosynthesis from the leaves to other parts of the plant, where it is used to provide energy for all cellular processes Ground tissue - Makes up most of the plant - Used to store food and water in the roots - Mesophyll: in the leaves photosynthesis and gas exchange occurs in these specialized ground tissues Meristematic tissues - Unspecialized tissue found in the roots - Capable of specialization into any other type of plant tissue Biology Page 17 Circulatory System January 7, 2025 10:08 AM Pipes - Arteries - Veins - Capillaries Arteries - Large thick walled elastic vessels - Carry blood away from heart - Blood in arteries is normally oxygenated - Arteries become gradually smaller - Very small, thin arteries are called arterioles (these lead to capillaries) Capillaries - Thin, hair-like structures - Walls are composed of single cells - Blood cells roll slowly through capillaries, one after another - Slow flow so enough time for materials to be exchanged between capillary and cells and tissues it supplies - Waste, oxygen, carbon dioxide, nutrients, hormones, ions all pass between the capillary and the cells - Large beds of capillaries supply tissues and organs, reaching every cell Veins - Capillaries drain into larger vessels, called venules - These, in turn, become bigger and drain into veins - Veins are large, floppy vessels which carry blood back to the heart - Blood in veins is normally deoxygenated - Two largest veins: inferior vena cava and superior vena cava - Both carry blood back to the heart Blood - Blood is a tissue with a variety of cells and functions Biology Page 18  - Blood is a tissue with a variety of cells and functions - Include red blood cells, white blood cells (leukocytes) and platelets (pieces of cells) - Includes plasma, the fluid in which cells are suspended Parts of the Heart - A protective layer called the pericardium surrounds the heart - There is nervous and connective tissue in the heart - Nervous tissue is involved in the beating of the heart - Connective tissue is involved in creating the blood vessels that supply the heart with its own blood supply 4 chambers of the heart - Deoxygenated blood flows into the Vena Cavas - Then enters the Right atrium - Blood then flows into the Right Ventricle, which contracts, ejecting blood into lungs - Blood returns from lungs (now rich in oxygen) - It enters the Left Atrium, where it collects - Blood then travels to the Left Ventricle - It is ejected out to the body via the Aorta (an artery) Heart Diseases - Coronary Artery Disease: coronary arteries provide blood to heart muscle tissue, and plaque build up can partially block them - Heart attack: coronary arteries become completely blocked (no oxygen or nutrients to heart muscles), the heart stops pumping and heart tissue starts to die Lymphatic System - Drains the interstitial fluid - This is the fluid that lies between the cells - Drains into small lymphatic vessels, which accumulate into ducts - Eventually the fluid flows back to the heart and come back to the Right Atrium via the Vena Cava Biology Page 19 Respiratory system January 8, 2025 7:01 PM - An organ system made up of nose, mouth, trachea, bronchi, and lungs - Brings oxygen into the body and allows carbon dioxide to leave the body - Cellular respiration: sugar + oxygen -> water + carbon dioxide + energy - Works closely with the circulatory system The path air takes - Enters through mouth and nose - Passes through pharynx (throat) - Travels down trachea (windpipe) - Trachea separates into two branches called bronchi which deliver air to the lungs - Each bronchus branches again and again (bronchioles) ending in tiny air sacs called alveoli Nasal passages - Filter, warm, and moisten air - Have hairs to remove foreign particles Some epithelial cells lining trachea and bronchi - Produce mucus - Have cilia (hair-like structures) - Trap bacteria and dirt particles Gas exchange - Main purpose of respiratory system Biology Page 20  - Main purpose of respiratory system - Happen in the alveoli of lings - Each alveolus is surrounded by a network of capillaries - Gases move between lungs and blood by diffusion How diffusion is made efficient - Each alveolus is surrounded by a capillary network, ensuring good blood supply - Alveoli provide very large surface area, and have very thin walls (as do capillaries) - Oxygen and carbon dioxide only have to diffuse through two thin walls Breathing - Involved muscles that move the ribs and the diaphragm, a large sheet of muscle underneath the lungs Exhalation - Diaphragm relaxes and pushed up, rib cage contracts = lung volume decreases - Changes pressure in lungs - Air pushes out of lungs Inhalation - Diaphragm contracts and flattens, rib cage expands = lung volume increases - Changes pressure in lungs - Air pulled into lungs Control of Breathing - Breathing is controlled by a part of the brain that detects the concentration of carbon dioxide - As levels of CO2 in the blood increase, sensors in the circulatory system send a message to the brain - The brain responds by sending a message of the diaphragm to contract (flatten) and muscles of the rib cage to expand Diseases of the lungs - Tuberculosis - Pneumonia - Pleurisy - Cancer - Emphysema - Bronchitis from infection Biology Page 21 Digestive system January 8, 2025 7:01 PM - The organ system that takes in, breaks up, and digests food and then excretes the waste Parts - Mouth - Esophagus - Stomach - Intestines - Liver - Pancreas - Gall bladder Digestive tract - One long tube with an opening at each end Human digestive tract - Includes: mouth, esophagus, stomach, small intestine, large intestine, and anus - Entire tract lined with epithelial tissue - Some of the epithelial cells, called goblet cells, secrete mucus - Mucus serves 2 functions: protect digestive tube from digestive enzymes, and allow Biology Page 22  - Mucus serves 2 functions: protect digestive tube from digestive enzymes, and allow material to pass smoothly through the digestive tube - Digestive tube also includes layers of muscle tissues and nerves The mouth - Begins breaking down food (digestion) in two ways - Mechanically - teeth and tongue - Chemically - enzymes in mouth - Saliva (water + enzymes) is produced by epithelial cells lining mouth - This breaks up and softens food so it can be swallowed and passed into the esophagus The Esophagus - Muscular tube, connects mouth to stomach - Special type of muscle: smooth muscle tissue - Movement is controlled by nerve tissue - Contractions slowly move food along The stomach - Holds and churns food - Lining contains cells that produce digestive enzymes and acids - Smooth muscle tissue contracts to mix contents - Nerves in the stomach signal when we are full The intestine - Between stomach and anus - Cells of lining secrete mucus - Also contains smooth muscle tissue The small intestine - Narrower than the large intestine, but longer - Where most digestion occurs - Nutrients diffuse through wall of small intestine into bloodstream The large intestine (colon) - Larger diameter than the small intestine, but shorter - Lining absorbs water from indigestible food - Remaining matter is excreted as feces through anus Accessory Organs - Liver, pancreas, and gall bladder - Supply digestive enzymes to aid digestions Liver - Produces bile (helps to breakdown fats) Pancreas - Produces insulin (regulates blood sugar levels) Gall Bladder - Concentrates bile produced by the liver Diseases - Colitis - inflammation of the colon lining - Diabetes - A disease in which the body's ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood and urine - Chron's - is an inflammation of the digestive tract, thought to be caused by an abnormal Biology Page 23 - Chron's - is an inflammation of the digestive tract, thought to be caused by an abnormal immune reaction to food, bacteria, or even lining of the intestines or colon Biology Page 24