Biology Test #1 (1) PDF

Biology Test Lesson 1: Cells What is a theory? ​ A principle formed to explain the things already shown in data What is a hypothesis? ​ An assumption made before research has been done ​ It can be tested to see if it might be true ​ “If {this happens} then {this happens} Cell Theor...

Biology Test Lesson 1: Cells What is a theory? ​ A principle formed to explain the things already shown in data What is a hypothesis? ​ An assumption made before research has been done ​ It can be tested to see if it might be true ​ “If {this happens} then {this happens} Cell Theory 1.​ All living things are made up of one or more cells and their products 2.​ The cell is the simplest unit that can carry out all life processes 3.​ All cells come from other cells; they do not come from non-living matter Types of Cells 1.​ Prokaryote - A cell that does not contain a nucleus or other membrane-bound organelles 2.​ Eukaryote - A cell that contains a nucleus and other organelles each surrounded by a membrane Prokaryotes ​ Very simple and small ​ Organisms are single-celled ​ Does not have a nucleus ○​ Cells have no membrane bound organelles but do have some organelles ○​ ONLY contains ​ A cell membrane, cell wall ​ Ribosomes ​ Cytoplasm ​ Nucleoid - genetic materials (differs from nucleus because it is poorly organized and small) ​ 2 Kingdoms ○​ Bacteria ○​ Archaea Eukaryotes ​ Cells have a more complex organization than prokaryotes ​ Organelles exist to perform a specific function within the cell ​ Have membrane bound organelles ​ Cells are larger than prokaryotes ​ Can be single-celled or multicellular organisms ​ 4 kingdoms  ○​ Protists ○​ Fungi ○​ Plants ○​ Animals Characteristics of Living Things (MRS GREN) 1.​ Movement - All living things move in some way (whether it be obvious or subtle) 2.​ Respiration - A chemical reaction that happens with cells to produce energy from nutrients ​ Word Equation ○​ Glucose + Oxygen → Carbon Dioxide + Water + Energy ​ Chemical Equation ○​ C6H12O6 + O2 → CO2 + H2O + Energy 3.​ Sensitivity - The ability to detect and respond to changes in the environment 4.​ Growth - All living things increase in size, even single-celled organisms (getting bigger, building body parts) 5.​ Reproduction - The ability to reproduce and pass genetic information to offspring (making new organism) ​ Asexual - production of offspring from only one parent; the offspring inherits genetic identical to parent ​ Sexual - producing offspring from two parents; the offspring inherits genetic information from each parent 6.​ Excretion - Getting rid of waste (other than from the digestive system_ ​ E.g. Eliminating Carbon Dioxide 7.​ Nutrients - The intake and use of nutrients for energy, growth, and development ​ Photosynthesis - chemical reaction allows plants to create glucose (nutrient) ○​ Word Equation ​ Solar Energy + Carbon Dioxide + Water → Glucose + Oxygen ○​ Chemical Equation ​ Light Energy + CO2 + H2O → C6H12O6 + O2 Lesson 2: Organelles What is an organelle? ​ A cell structure that performs a specific function for the cell Organelle Description and Function Plant, Animal, or Both Cytoplasm ​ Jelly-Like substance that fills cells Both ​ An organelle in the cell are suspended in the cytoplasm ​ Allows for the cell  ​ reactions to occur Cell Membrane ​ Supports the cell Both ​ Double layered ​ Allows some substances to enter while keeping others out Nucleus ​ Control center of cell Both ​ Has a semi-permeable membrane ​ Contains genetic info that controls all cell activities ○​ Contains DNA/chromatin Nucleolus ​ Area inside the nucleus where ribosomes Both are made DNA/Chromatin ​ DNA - the hereditary material of the cell, Both contains all the cellular instruction for the entire organism ​ Chromatin - Lose strands of DNA that coil up to form chromosomes during cell division Mitochondria ​ The “powerhouse” of the cell Both ​ Makes energy available to the cells ​ Sugars are converted into visible energy (ATP) ​ Cite of cellular respiration Endoplasmic ​ Network of tubes that runs through the Both Reticulum (ER) cytoplasm from the nuclear membrane to the cell membrane ​ Use for transporting material and proteins ​ Involved in protein and lipid synthesis ​ Usually has ribosomes attached Vacuoles ​ A single layer of membrane enclosing fluid Both in a sac ​ Functions - these include storage of food or wastes or water, removing waste from cell or maintaining cell pressure Golgi Body ​ Collect and process materials to be Both removed from the cells ​ Makes and secretes mucus ​ Modifies proteins and lipids (fats)  Cell Wall ​ Located just outside the cell membrane Plant provides support and protection for the cell Chloroplasts ​ Contains chlorophyll and give/leaves their Plant green colour ​ Absorbs light energy ​ Site of photosynthesis Ribosomes ​ Where proteins are assembled Both Centrioles ​ Create spindle fibres which are required for Animal cell division Lysosomes ​ The garbage can of cells Mostly in Animal ​ Lysosomes can help cell self-direct in a process called programmed cell death, or apoptosis Lesson 3: Comparing Plants and Animal Cells + Diffusion and Osmosis Plant and Animal Cells ​ All need the same thing ○​ Source of energy ○​ Nutrients ○​ Water ○​ Gases Difference Between Plants and Animal Cells Plant Cells 1.​ One central vacuole 2.​ Cell wall - for rigid shape and structure 3.​ Chloroplast - for photosynthesis to create glucose using energy from the sun Animal Cells 1.​ Many small vacuoles 2.​ No cell wall, more flexible (irregular shape) 3.​ Centrioles-produces spindle fibres required for cell division Why do plants need a cell wall? ​ Plant cell swell up because they absorb large amounts of water through osmosis ​ The vacuole gets completely filled with water and presses against the cell wall ​ But the cell does not burst due to the presence of the cell wall What is Diffusion?  ​ Diffusion - A transport mechanism for moving chemicals into and out of the cell, from an area of high concentration to an area of low concentration ​ Concentration - the number of substance (solute) present in a given volume of solution What is Osmosis? ​ Osmosis - the movement of a fluid (usually water), across a membrane from an area of low solute concentration to higher concentration Transport in Cells: Diffusion and Osmosis ​ The exchange of materials from intra/extracellular space through cell membrane ​ Diffusion - high → low concentration ○​ E.g. gas exchange from lungs, CO2 from air to leaves in plants ​ Osmosis - Water moving from low → high concentration ○​ Plant cells swell, animal cells can burst ○​ E.g. absorption of water to plant roots, water to small intestine Why do Cells Divide? 1.​ Growth 2.​ Repair 3.​ Reproduce Why do cells divide when they get too big? ​ If a cell grows larger instead of dividing, diffusion will be too slow and the cell will not be able to obtain nutrients and get rid of wastes efficiently, which ultimately would kill the cell Surface Area/Volume Ratio ​ As a cell grows, volume increases faster than surface area, leading to a decreased SA:Vol ratio ○​ If metabolic rate exceeds the rate of exchange of vital materials and wastes (low SA:Vol ratio), the cell will eventually die ○​ Hence growing cells tend to divide and remain small in order to maintain a high SA:Vol ratio suitable for survival Lesson 4: Cell Cycle - Part 1 Why do cells need to divide? 1.​ Growth 2.​ Repair 3.​ Reproduction Growth ​ As multicellular organisms grow, the number of cells increases ​ Why does the number of cells increase instead of increasing the size of the cells ​ In order for cells to grow and survive, nutrients (ie., water, oxygen, sugars) and carbon dioxide and wastes must be able to move in and out of the cell in an efficient way Repair ​ To repair damaged cells and to replace dead ones  ​ Why do cells die? ○​ They are old ○​ They are not needed anymore ○​ They can’t function ○​ They are damaged Reproduction ​ Asexual reproduction ○​ Single celled organisms undergo cell division in order to create their offspring ○​ Produces identical offspring ​ Sexual reproduction ○​ Cells containing half the genetic information from two different individuals come together to produce offspring ○​ Produces genetically different offspring The Cell Cycle ​ The cell cycle is responsible for the growth and development of individuals by allowing cells to divide ​ All eukaryotic cells grow and divide through 3 distinct phases ​ The lifespan of a cell includes - growth, nuclear division and cellular division Three Phases of the Cell Cycle ​ Interphase - phase during which the cell performs its normal functions and gets ready for mitosis (cell is growing) ​ Mitosis - process that endures each new cell gets a full set of DNA instructions (PMAT) ○​ “Nuclear division” is the first part of cell division ​ Cytokinesis - division of cytoplasm and organelles and is the second part of cell division Interphase ​ The longest stage ​ Cells carry out normal activities and prepare for mitosis ​ 3 subphases of Interphase: ○​ G1 - cell undergoes normal cell activities and grow ○​ S - replication of DNA (chromatin) cell continues to grow ○​ G2 - Growth preparation for mitosis, usually the shortest of the phases The S Phase (synthesis phase) ​ DNA must be replicated before cell division, this occurs in S phase ○​ Therefore, each new cell will have an identical copy of DNA Checkpoints ​ Proteins that control the cell cycle, making sure each step happens at the right time. They can speed up or slow down cell division until everything is ready for the next step ○​ There are not enough nutrients ○​ The DNA is damaged ○​ The DNA did not replicate properly  ○​ The cell is not ready to divide yet ​ G0 The cell is not actively dividing nor preparing to divide (resting state). G0 is a permanent state for some cells once they reach maturity, while others may restart division if they get the right signals The stages of the cell cycle 1.​ Interphase 2.​ Mitosis a.​ Prophase b.​ Metaphase c.​ Anaphase d.​ Telophase 3.​ Cytokinesis Lesson 4: Part 2 Interphase ​ Cell carries out normal life activities ○​ Includes growth, cellular respiration, and any specialized functions ​ During this stage, the genetic material, is in very long invisible strands called chromatin ​ When the cell prepares for cell division, it duplicates the strand of DNA creating two identical strands of genetic material ​ Cell grows and prepares for Mitosis Phase Description Diagram  Prophase ​ DNA condenses (prep) ​ Nuclear membrane breaks down ​ Spindle fibres begin to form Metaphase ​ Each chromosome is attached to spindle (Middle) fibres by the centromere ​ Chromosomes are lined up at the midline Anaphase ​ Centromere splits and sister chromatids (Apart) separate ​ Daughter chromosomes move to opposite sides of the cell ○​ Pulled by the spindle fibres Telophase ​ Daughter chromosomes stretch out, (Two) become thinner, and no longer visible ​ Spindle fibres dissolve ​ New nuclear membrane forms around daughter chromosomes ○​ Cells appears to have two identical nuclei Cytokinesis ​ Final stage of cell division ​ Cytoplasm divides ​ Two genetically identical daughter cells are produced  ​ Animal Cells - The cell membrane pinches in to separate the nuclei ​ Plant Cells - A cell plate forms at the equator to separate the nuclei Type of Cell Description Diagram Animal Cells ​ A cleavage furrow forms in the cell membrane which separates the two new daughter cells Plant Cells ​ Vesicles fuse together along the midline creating a cell plate which develops in a cell wall separating the two new daughter cells Lesson 5: Cancer Recall ​ In interphase, the cell undergoes checkpoints before the cell is ready to go into cell division ​ What are the checkpoints for? ○​ Making sure the DNA has replicated properly during the S phase ○​ There are enough nutrients to support the cell ○​ The surrounding environments are suitable (i.e., no messages from other cells saying otherwise) What is Cancer? ​ Diseases in which cells grow and divide out of control ​ Checkpoints fail and fail to kill off the cell (apoptosis) ○​ The cell does not stay in interphase for the normal amount of time ​ Some types of cancers are hereditary (run in families), while others are caused by environmental factors Contact Inhibition ​ Normal cells have a growth inhibition, meaning when they come in contact with another object they will stop growing ​ Cancer cells lack this inhibition and therefore continue to grow Cell Growth Rates and Cancer ​ Uncontrolled growth and division may create a rapidly growing mass of cells that form a tumor (neoplasm)  ​ Two types of tumors ○​ Benign - A tumour that does not affect surrounding tissues other than by physical crowding them ○​ Malignant (AKA a cancerous tumor) - A tumor that interferes with the function of crowding cells Metastasis ​ Metastasis - the process of cancer cells breaking away from the original (primary) tumor and establishing another (secondary) tumor elsewhere in the body ​ This is one of the reasons why cancer is so dangerous Normal vs. Cancer Cells Causes of Cancer ​ Mutations ○​ Mutation are random change in the DNA ○​ Mutations can either kill the cell or allow the cell to survive and continue to grow and divide ○​ When the DNA responsible for cell division mutated, DNA starts behaving abnormally, and cells may become cancerous ​ Carcinogens ○​ Carcinogens are any environmental factors that cause cancer ​ Smoking (Tobacco) ​ Radiation (X-rays) ​ UV rays (Sunlight) ​ Viruses (HPV, and Hepatitis B) ​ Hereditary ○​ Some cancers appear to be somewhat hereditary ○​ A genetic link makes it more likely that you will develop a particular type of cancer (e.g., some breast cancers) ○​ DNA passed from one generation to the next may contain information that leads to disease Cancer Screening  ​ Cancer screening means checking for cancer even if there are no symptoms ​ Screening does not prevent cancer, but it does increase the chance of detecting it early ​ Not all cancer is detected through screening Different Types of Cancer Screening 1.​ Self Examination - checking for irregular lumps (breast and testicular cancer) 2.​ Pap Test - involves taking a sample of cervical cells, which are then checked for cancer 3.​ Blood Test - checks for prostate cancer and colon cancer 4.​ Skin Checks - screening for irregular moles, new growths, and sores Reducing Your Cancer Risk ​ Risk Factors ○​ Personal and family medical history ○​ Carcinogens (sometimes in your control) ○​ Health choices (in your control) ○​ Inform yourself and minimize your exposure to known cancer risks ○​ Ways to reduce risk: ​ Eat a healthy balance diet ​ Exercising regularly ​ Reducing your amounts of carcinogens Imaging Technologies 1.​ Endoscopy - A flexible fiber-optic tube with a strong light source and camera to look for abnormal growths and take samples if needed ○​ The sample can be studied under a microscope 2.​ Medical Imaging ○​ X-ray ​ Beams of X-rays ○​ Ultrasound ​ Use high frequency sound waves to create an image ○​ CT scan ​ Takes multiple x-rays from different angles to create a 3D image ○​ MRI (magnetic resonance imaging) ​ Radio waves and magnetic fields create 3D images 3.​ Biopsy ○​ A sample of tissue is surgically removed to see if it is cancerous, and is examined under a microscope ○​ Lymph nodes are small structures that work as filters for foreign substances, such as cancer cells and infections. When there’s a problem, such as infection, lymph nodes may swell or enlarge as they work to filter out the “bad” cells ​ Check lymph nodes to see if cancer has spread Treatments for Cancer 1.​ Surgery ○​ Physically removing cancerous tissue ○​ Done if tumor is easily accessible and well defined 2.​ Chemotherapy ○​ Treats cancer using drugs ○​ Drugs can be injected or taken orally ○​ Drugs slow or stop cancer cells from dividing ○​ Many side effects ​ Ex. hair cells - slows down the growth not only of cancerous cells but of fast growing cells such as hair cells 3.​ Radiation ○​ Cancer cells are easily damaged by ionizing radiation ○​ Targets DNA of daughter cancer cells and prevents them from dividing ○​ Radiation is directed by focus beam or implanting radioactive source in the tumor