S1 Bio Notes PDF

A2.2 Cell structure Key Features of All Cells Cells are the basic structural unit of all living organisms Unicellular organisms have only one cell, while multicellular organisms have many cells All cells contain the following key features: ○ genetic material for producing m...

A2.2 Cell structure Key Features of All Cells Cells are the basic structural unit of all living organisms Unicellular organisms have only one cell, while multicellular organisms have many cells All cells contain the following key features: ○ genetic material for producing mRNA (made by the process of transcription) and proteins ○ Cytoplasm: composed mainly of water, containing enzymes for chemical reactions ○ Plasma membrane: composed of lipids, controlling movement of substances in and out of the cell Prokaryotic Cell Structure There isn’t a nucleus (instead nucleoid) They are unicellular organism like bacteria There’s a single naked, circular, chromosome Prokaryotic cells are all unicellular The Cytoplasm is the water-like base The 70s ribosomes are the protein makers The Plasma Membrane separates the interior from the cell wall The Cell wall is the outer layer of the cell The Flagella helps the bacteria move Eukaryotic Cell Structure Only the animal cell doesn’t have a cell wall Has a nucleus (control center of cell) (stores DNA) Chromosomes (created when a cell is ready to divide) consists of DNA and histones (protein) Vesicles transport protein (made by 80s ribosomes) from Rough endoplasmic reticulum to the Golgi Apparatus/Body The Golgi Apparatus/Body customizes proteins into forms the cell can use The Nucleolus is the structure in the nucleus which creates 80s ribosomes Lysosomes break down debris using enzymes located inside them (like trash collectors) The mitochondria is the powerhouse of the cell Cellular respiration takes place in the mitochondria to produce ATP The mitochondria has double membranes with the inner being Cristae, which increases the surface area for enzymes Chromatin is the tangled, spread-out form of DNA in the Nuclear Membrane  Vacuoles store materials (like a sac) within the cell The cytoskeleton maintains the cell shape by using microfilaments and microtubules Photosynthesis takes place in the chloroplast ( converting light energy to chemical energy) The chloroplast produces Chlorophyll( that’s why the plants have the color green) Organelles are specialized parts of a cell that have special jobs DNA dictates what a cell does and how it does it Photoautotrophic is the organism that captures sunlight for energy The primary use of the plasma membrane is to control what enters and exits the cell Flagella shows up in some animal cells (in the form of sperm) Cilia are small hair-like extensions that are present in animal cells but not plant and fungi cells Nuclear pores allow molecules to enter and exit the nucleus The nucleus and mitochondria both are structurally similar because they both are double membraned and they both contain their own DNA and Ribosomes Organelles can be classified by the number of membranes surrounding them: Organelles Number of membranes Ribosomes 0 ER, Golgi, Lysosomes, Vesicles 1 Nucleus, Mitochondria, Chloroplast 2 Comparing Eukaryotic Cells Feature Animals Fungi Plants Cell wall No Yes (Chitin) Yes (Cellulose) Vacuoles small Large Large (store materials (like a sac) within the cell) Plastids No No Yes (Chloroplasts) Centrioles: Yes No No Organelle involved in cell division Cillia/ Flagela Sometimes (sperm) No Some Atypical Eukaryotic Cell Structures/ Limitations of Cell Theory Anucleate cells (no nucleus) Red Blood cells have a life span of 4 months because they don’t have a source of protein due to not having a nucleus. Their purpose is that they transport oxygen to every part of the cell. Sieve tube elements have a nucleus but they get rid of it so sap can flow more easily. They then have to rely on nearby cells called companion cells as a way of protein Viruses are nucleate organisms that is neither dead nor alive just infecting hosts Multinucleate cells (many nuclei) Skeletal muscle fibers is enclosed inside a plasma membrane like a cell, but is longer, larger, and have more nuclei. Aseptate fungi consist of thread-like structures called hyphae. These hyphae are not divided up into subunits containing a single nucleus. Instead, there are long undivided sections of the hyphae that contain many nuclei. Microscopy Skills Components of a light microscope Coarse focus (big knob) Fine focus (small knob) Light Stage Slide Eyepiece Objective lens (magnifiers) Stage control Focusing 1. Start with specimen and lens far apart 2. Use coarse focus (Big knob) to bring the specimen into view (further / closer) 3. Use fine focus (Small knob) to get the sharpest focus Microscopy Developments A compound light microscope uses visible light and different lenses to mostly magnify and view small creatures. Electron microscopes use beams of electrons, allowing for magnification at much higher resolutions than other microscopes. Which allows to see the cell more accurately and see the organelles. Calculating size from a Microscope: Magnification = Size of Image/actual size Actual size = Size of image/magnification Image size = magnification x actual sizes Theories: Cell Theory All living organisms are made from cells Organisms are either unicellular (one cell) or multicellular (many cells) Cells come from pre-existing cells Life Processes in Organisms - Both Unicellular and Multicellular organisms carry out all life functions in a single-cell - Key life processes include: ( Mr. Mehngr) 1. Metabolism - producing enzymes for chemical reactions 2. Reproduction asexual or sexual reproduction 3. Movement - using cytoplasmic flow for locomotion 4. Excretion - removing metabolic waste products 5. Homeostasis - regulating internal conditions 6. Nutrition - feeding on smaller organisms 7. Growth - increasing in size and mass 8. Response - reacting to stimuli B2.1 Membranes and membrane transport Fluid Mosaic Model: The Fluid Mosaic Model is a phospho-lipid bilayer It has: Hydrophilic phosphate polar heads Hydrophobic lipid non polar tails which are floating laterally within the bilayer Integral proteins Peripheral protein (small) Carbohydrate part of a glyco-lipid (Glucose + lipid) and glyco-protien (Glucose + protien) to allow cells to identify each other (Attached to proteins on outside membrane layers) Cholesterol (located inside the tails) to control fluidity of the cell Pore through channel / transport protein Types of Transport: Passive Transport: Doesn’t need energy Goes with the concentration gradient (HIGH to LOW) Simple diffusion is a type of passive transport where very small, nonpolar molecules (mostly gasses) go through the cell membrane and directly through the bilayer, without needing a channel protein (Ex: Co2 and Oxygen) Facilitated diffusion is when channel proteins change shape (some open and close based on stimulus) to let larger, polar molecules pass Osmosis is the passive movement of water molecules through aquaporins (type of channel protein) from a region of lower solute concentration to a region of higher solute concentration, across a partially permeable membrane. Active Transport: Needs ATP energy Goes against the concentration gradient (LOW to HIGH) Endocytosis is when the cell fuses with the large molecule it’s taking inside Exocytosis is when the cell gets rid of molecules inside it (ex: pooping) B2.2 Organelles and Compartmentalization Compartmentalization allows for: The specialization of each organelle Allows for the creation of a certain microenvironment Creates a fixed location when you link a certain activity with a certain compartment, making it easier to locate a certain compartment Created higher efficiency where all activities can take place without any distractions -Lysosomes are examples of compartmentalization because they contain enzymes within them that break down structure -Organelles are specialized parts of a cell that have special jobs Some structures aren’t organelles though: Cell wall- outside the plasma membrane so outside the boundary of the cell (extracellular) Cytoplasm— not enclosed by a membrane. Cytoskeleton—very extensive structure that extends through the cytoplasm and is not discrete. The cell wall, cytoskeleton, and cytoplasm are not considered organelles because they are not enclosed by a membrane. Unlike other organelles, they do not have a protective membrane surrounding them. This lack of membrane distinguishes them from true organelles. Separation of the nucleus and cytoplasm: A2.3 Cell Size (specialization) Cells are of many different sizes and shapes. Volume refers to the amount of space inside of the cell Surface area (SA) of a cell refers to the area exposed to the external environment To find surface area and volume = x3 As the cell becomes larger, the surface area decreases while the volume increases As organisms increase in size, the surface area-to-volume ratio of their cells decreases along with the efficiency Surface area is made up of the plasma membrane Surface area can be increased by dividing them up into smaller pieces Scientific method: The scientific method is about normal people doing normal things It’s a process of steps Consist of 1. Observation: use of 5 senses 2. Research: use reliable sources 3. Hypothesis: A prediction of what will occur 4. Experiment: collects Qualitative data (descriptions) Quantitative data (numbers) Has an independent variable (the change) the dependent variable (The thing being measured) and control variable (the thing staying the same) 5. Data 6. Conclusion The Human Body Systems: The human body is organized at different levels, starting with the cell and ending with the entire organism Cells are the basic units of structure and function in the human body, as they are in all living things. Each cell carries out basic life processes that allow the body to survive. (Ex: nerve cells) Tissues are a group of connected cells that have a similar function. The four types of tissues are: ○ Connective Tissues, which are made up of cells that form the body’s structure (Ex. bone) ○ Epithelial tissues, which are made of cells that line inner and outer surfaces (skin) and protect the body and its internal organs, secrete substances like hormones, and absorbs substances like nutrients. ○ Muscle tissue, which is made of cells that can become shorter which help the body to move ○ Nervous tissue, which is made of nerve cells that carry electrical messages and makes up the brain and the nerves that connect the brain to the rest of your body Organs are structures which consist of 2 tissues working together (Ex. brain, heart, lungs, skin, and kidneys) Organ systems are a group of organs that work together to carry out a complex function and each organ does its own thing to contribute to the accomplishment of the function (Ex. Skeletal System, Muscular System, Digestive System, etc.) Organ System Major Tissues and Organs Function Cardiovascular Heart; blood vessels; blood Transports oxygen, hormones, and nutrients to the body cells. Lymphatic Lymph Vessels Defend against infection and disease, moves lymph between tissues + blood stream. Digestive Stomach, Small + large Digests foods and absorbs intestine nutrients, minerals, vitamins, and water. Endocrine Ovaries Produces hormones that communicate between cells. Integumentary Skin, Hair, Nails Provides protection from injury and water loss, Muscular Cardiac (heart) muscle, Involved in movement and skeletal muscle, smooth heat production. muscle Nervous Brain, Spinal cord, nerves Collects, transfers, and processes information. Reproductive 🚺 Uterus; vagina; fallopian Produces gametes (sex cells) 🚹 tubes; ovaries Penis; testes; seminal vesicles and sex hormones Respiratory Lungs Brings air to sites where gas exchange can occur between the blood and cells (around body) or blood and air (lungs). Skeletal Bones, Cartilage, Ligaments Supports and protects soft tissues of body; Urinary Kidney, Urinary bladder Removes extra water, salts, and waste products from blood and body Immune White blood cells Defends against diseases. Cardiovascular/Transport/Circulatory system: Heart + Blood vessels: Steps (in human toe): 1. Oxygen-poor blood flow through the Inferior vena cava (because blood from under the heart) to the right atrium 2. The right atrium receives oxygen-poor blood from the body, pushing it to the right ventricle through a valve 3. The right ventricle pumps oxygen-poor blood toward the lungs through the Pulmonary Artery 4. The now oxygenated blood flows through another pulmonary vein to the left atrium 5. The left atrium receives oxygen-rich blood from the lungs, pushing it to the left ventricle 6. The left ventricle pumps oxygen-rich blood through the Aorta valve, reaching the Aorta, a large artery which carries oxygenated blood throughout the body. Blood vessels components: Arteries: ○ Carry blood away from the heart ○ Carries oxygenated blood (EXCEPT PULMONARY ARTERY) ○ Largest artery is the Aorta (Output) Veins: ○ Carries blood towards the heart ○ Carries deoxygenated blood (EXCEPT PULMONARY VEINS) ○ Longest vein is the Vena Cava (input) Capillaries ○ Comes from Arteriole ○ Smallest type of blood vessels ○ Connects small arteries and veins Blood: Blood carries oxygen, the main activator in cellular respiration Blood is a Fluid Connective Tissue Blood protects the body from infection, repairs body tissues, transports hormones, and controls the body’s acidity The fluid part of blood is called plasma (a watery golden-yellow liquid that contains dissolved substances and 3 blood cells.) ○ Red Blood cells (RBC): Carry oxygen Contain hemoglobin (protein with iron that binds with oxygen) Cell life span is 120 days Don't contain a nucleus, allowing for more hemoglobin ○ White Blood Cells (WBC): Larger than RBC but fewer Defend the body against foreign bacteria, viruses and other pathogens Phagocytes (fag3an), a type of WBC, swallows and destroys microorganisms, debris, neutrophils, bacteria, and other parasites Lymphocytes fight infections caused by bacteria and viruses ○ Platelets: Cell fragments involved in blood clotting Plug tears in blood vessels Release chemicals that are needed for clotting to occur Blood type is determined by the presence or absence of antigens Most common known blood types are the ABO and Rhesus ○ ABO blood type: ○ Rhesus blood type is determined by one common antigen. A person may either have the antigen (Rh+) or lack the antigen (Rh-). Cardiovascular Diseases (CVD): A disease that affects the heart or blood vessels is called a cardiovascular disease The leading cause of CVD is Atherosclerosis Atherosclerosis is the build up of Plague inside arteries Plaque consists of cell debris, cholesterol, and other substances A high-fat diet and smoking contribute to plaque buildup As plaque builds up, it narrows the arteries and reduces blood flow. Coronary Heart Disease Is the build up of plague inside the Coronary artery (artery that supplies the heart muscle blood) A blocked blood vessel causes cardiac muscle fibers to die, causing a heart attack Blockage of circulation in the brain can cause a stroke (Loss of brain function) Old age, high blood pressure, having a previous stroke, diabetes, high cholesterol, and smoking are all risk factors for a stroke Healthy lifestyle choices can reduce the risk of developing CVD.  Respiratory System Functions of the respiratory system: The functions of the respiratory system are gas exchange, ventilation, and respiration Respiration is the process in which gases are exchanged between the body and the outside air. Respiration consists of two parts ○ 1. CO₂ is released from the body and oxygen from outside air is taken (Ventillation) ○ 2. The circulatory system takes CO₂ from the body and gives it Oxygen (Gas exchange) Breathing, or ventilation, is the two-step process of drawing air into the lungs (inhaling) and letting air out of the lungs (exhaling). Gas exchange is the process through which gases are transferred across cell membranes to either enter or leave the blood without the use of energy The difference between cellular respiration and the respiratory system’s respiration is that the respiratory system removes CO₂ and provides oxygen while cellular respiration removes CO₂ and uses oxygen. Gas exchange helps maintain homeostasis by supplying cells with oxygen, carrying away carbon dioxide waste, and maintaining proper pH of the blood. Aerobic respiration requires oxygen to create more energy within the mitochondria Anaerobic respiration doesn’t require oxygen within the cytoplasm Feature aerobic Anaerobic Definition Respiration that occurs Respiration that occurs in the presence of in the absence of oxygen. oxygen. Oxygen Requirement requires oxygen. Does not require oxygen. Location Mitochondria. Cytoplasm. Energy Yield Produces a high amount Produces less energy of energy (around 36-38 (around 2 ATP per ATP per glucose glucose molecule). molecule). End Products Lactic acid is not Lactic acid (in animals) produced. or ethanol and carbon dioxide (in plants/yeast). Lactic Acid Formation Lactic acid is not Lactic acid is produced produced. in muscle cells during intense activity. Examples Running, swimming, and Sprinting, weightlifting other sustained and fermentation in activities. yeast Respiratory System Organs: The Brainstem is the organ located in the brain which detects the levels of oxygen and carbon dioxide in the blood and regulates breathing accordingly The respiratory tract is a continuous system of passages that carry air into and out of the body. The organs of the respiratory system that bring air into the body are divided among the upper respiratory tract, aka. organs involved in conduction, (movement of air into and out of the body), and lower respiratory tract. The organs of the respiratory system include the nose, nasal cavity, pharynx (throat), larynx (voice box), lungs, trachea (windpipe), and bronchi. The nose filters, warms, and moistens the air we breathe using the hairs and mucus inside our nose The pharynx is a long tube that is shared with the digestive system. Both food and air travel through the pharynx. The Epiglottis prevents food from going down the trachea The larynx/voice box, contains vocal cords, which allow us to produce vocal sounds by letting air pass through thin tissues The trachea/windpipe is a long tube that leads down to the chest to the lungs to form the right and left bronchi The left and right bronchi branch into the secondary bronchus, then the tertiary bronchus, then finally into bronchioles within each lung (diameters become smaller with each branch). Your right lung has 3 lobes while your left lung has 2 The bronchioles lead to alveoli, the sites of gas exchange. Journey of a breath of air : Inhalation (Breathing In) (Active process): The diaphragm contracts and moves downward, increasing space (becomes flattened) in the chest cavity. The External Intercostal muscles (between the ribs) contract, lifting the ribcage and expanding the lungs Air enters through the nose or mouth. The air is warmed, moistened, and filtered by the nasal cavity. It passes through the pharynx (throat) and then the larynx (voice box). Air moves down the trachea (windpipe). The trachea divides into two bronchi (one leading to each lung). Air Passage Through Lungs: The bronchi branch into smaller bronchioles within the lungs. Air travels to the tiny air sacs called alveoli at the end of the bronchioles. Gas Exchange in Alveoli (Pulmonary Gas Exchange): Oxygen from the air diffuses across the thin walls of the alveoli into the capillaries (tiny blood vessels). Carbon dioxide from the blood diffuses into the alveoli to be exhaled. Transport of Oxygen (Peripheral Gas Exchange): Oxygen attaches to hemoglobin in red blood cells. Blood carries oxygen to the body tissues through the circulatory system. Exhalation (Breathing Out) (Passive): The diaphragm relaxes and moves upward, reducing space in the chest cavity. The intercostal muscles relax (contract), causing the ribcage to lower and lungs to compress. Air pressure inside the lungs is high Carbon dioxide-rich air travels back through the bronchioles, bronchi, and trachea. Air exits the body through the mouth or nose. Respiratory Diseases: Asthma is when the air passages of the lungs frequently become too narrow. It causes difficulty breathing, coughing, and chest tightness. It is usually caused by allergens, hard exercise, stress, or other symptoms Pneumonia is the filling of Alveoli with water, preventing gas exchange. It is caused by an infection or an injury in the lungs, and can be identified if a person is having chest pain, a hard time breathing, and is coughing a lot Emphysema is when the Alveoli walls break down, reducing the amount of gas that is exchanged. This is due to smoking and it causes shortness of breath COPD: Reduction in the number of alveoli Lung Cancer: It is the overproduction of cells inside the lungs and could be fatal, this usually occurs due to smoking chemicals like nicotine or tobacco. Having symptoms like coughing,shortness of breath, chest pain etc. Bronchitis/ Chest Cold: It is an infection that commonly occurs after a person has a cold or flu. It causes inflammation and a build up of mucus in the bronchial tubes in the chest How do we find out if you have a lung disease? Doctors ask for a spirometry test to identify if you have a lung disease, to see how severe a lung disease is, and to see if the medication you are on is working. A spirometer measures how fast and how much you can breathe A spirometer measures the volume of air you breathe out A spirometer uses L/s to measure