Cells - Gr. 10 Biology PDF

Cells Cells Living things - Have a lifespan - Grow in size, reproduce, repair themselves - Can sense and respond to changes in their environment - Require energy - Produce waste The cell - The smallest and most basic unit of life that displays the five characteristics of liv...

Cells Cells Living things - Have a lifespan - Grow in size, reproduce, repair themselves - Can sense and respond to changes in their environment - Require energy - Produce waste The cell - The smallest and most basic unit of life that displays the five characteristics of living things - Most cells have a cell membrane, cytoplasm, nucleus, mitochondria, and vacuoles - Cell theory 1) All living things are made up of one or more cells 2) Cells are the basic unit of life (cells can perform life activities) 3) All cells come from pre-existing cells (reproduction) Animal and plant cells Organelles in Both Plant and Animal Cells 1. Nucleus: Controls cell activities; contains DNA. 2. Cytoplasm: Jelly-like substance where chemical reactions occur. 3. Cell Membrane: Regulates what enters and exits the cell; provides protection. 4. Mitochondria: Produces energy (ATP) through cellular respiration. 5. Ribosomes: Synthesizes proteins. 6. Endoplasmic Reticulum (ER): ○ Rough ER: Studded with ribosomes; involved in protein synthesis. ○ Smooth ER: Synthesizes lipids and detoxifies toxins. 7. Golgi Apparatus: Modifies, packages, and distributes proteins and lipids. 8. Vacuoles: Stores nutrients, water, and waste. (Smaller in animal cells, larger in plant cells.) 9. Lysosomes: Breaks down waste and cellular debris. (More common in animal cells.) 10. Cytoskeleton: Provides structure and support; aids in cell movement. Organelles only in Plant Cells 1. Cell Wall: Provides rigidity, structure, and protection; made of cellulose. 2. Chloroplasts: Site of photosynthesis; contains chlorophyll. 3. Large Central Vacuole: Stores water, maintains turgor pressure for structure. Organelles only in Animal Cells: 1. Centrioles: Helps organize cell division. Inside the nucleus - Almost everything in every cell is controlled by DNA (deoxyribonucleic acid) - All bodies growth instructions are written into DNA - When a cell is about to replicate, DNA organizes itself into 23 pairs of chromosomes (for humans, different number for other organisms - Other organelles in the nucleus can read the DNS and send instructions for other cells and molecules to be built Cell growth Functions of cell division: - Growth - Healing and tissue repair - Reproduction - Inside of a cell, the organelles need a constant supply of water and nutrients (ions, oxygen, amino acids) - Smaller cells have a smaller surface area to volume ratio - This allows them to access nutrients passing through much more quickly - This makes it beneficial for a cell to have a small size instead of just being one large cell Cell nutrition - Plant and animal cells all need the same things: a source of energy, nutrients, water, and gases - Many chemicals need to be in solution (dissolved in water) so that they can be used in chemical reactions within the cell - The cell must get rid of carbon dioxide and other waste products Travelling through - When nutrients and gases move in or out of a cell, it’s called diffusion - When water moves in or out of a cell, it’s called osmosis Cell division for repair - Cell division allows organisms to repair injuries and replace dead cells - Smaller organisms can regenerate limbs - Larger organisms can only achieve repairs Cell division for reproduction - When cells reproduce fro growth or replacement, two identical copies of the original cell are made - When an organism produces a completely new organism via the same method, it is called asexual reproduction - In this process, only one parent is involved - Examples include aphids, hydras, and strawberry plants - Most multicellular organisms require sexual reproduction to reproduce - This requires two parents - Each parent provides a “sex cell” with half of their genetic material - The new offspring end up with a combination of each parent's DNA Asexual Reproduction Sexual reproduction - Only one parent - Two parents (sperm and egg) - Offspring are genetically identical to the - Offspring inherits genetic traits from both parent parents - No genetic advantage - Genetic diversity propagates through a species Cells cycle and Cancer The cell cycle As eukaryotic cells grow and divide they move through three stages which make up the cell cycle 1. Interphase (normal life) - The phase of the cell cycle during which the cell performs its normal functions and its genetic material is copied in preparation for the cell division 2. Mitosis (Splitting of DNA) - The stage of the cell cycle in which the DNA in the nucleus is divided; the first part of cell division 3. Cytokinesis (Splitting of cell) - The stage in the cell cycle when the cytoplasm divides to form two identical cells; the final part of cell division Limits of the cell cycle Cell division is controlled by a series of checkpoints. The nucleus receives messages at these checkpoints to help determine whether the cell needs to divide, continue, or self-destruct. A cell stays in interphase and does not divide if; - Signals from neighboring cells tell it not to divide - There are not enough nutrients available to provide fro more cells - The DNA inside the nucleus has not replicated yet - The DNA is damaged Cell division gone wrong: CANCER When cell division occurs in an uncontrolled manner and continues despite messages from the body to stop, it causes tumour which can become cancerous Tumour: A mass of cells that continue to grow and divide without any obvious function in the body Benign tumour: a tumour that does not affect surrounding tissues other than by physically crowding them Malignant tumor: A tumour that interferes with the functioning of surrounding cells; a cancerous tumour How many cells before a tumour can be felt? - A common ‘doubling time’ (the time taken for a complete cell cycle) is about 2 months - It takes 30 doubling times for a tumour to be felt under the skin (notice how it doesn’t take a very long time for the numbers to add up into the millions)  Doubling time Months Number of cancer cells 0 0 1 1 2 2 2 4 4 3 6 8 … … … 30 60 (5 years) 1,073,741,824 Environmental causes of cancer - A carcinogen is a substance or set of conditions that are known to increase the risk of cancer - Some common carcinogens are - Tobacco smoke - Radiation, such as x-rays and UV rays from tanning beds and sunlight - Some viruses, such as HPV and hepatitis B - Certain chemicals in plastics - When a group of people are exposed to carcinogen, many will get cancer but some may not Cancer screening (checking for cancer even though you have no symptoms) - Self examination (breast for females and testes for males) - Being aware of family history and informing GP - Pap test for cervical cancer (women over 18) - Prostate examination (Men over 40) - Screening does not prevent cancer, but it does increase the chance of detecting cancer early enough to successfully treat it Reducing your risk - To reduce the risk of getting cancer, you can consume more ‘superfoods’ - Try to avoid carcinogens - Recent evidence also suggests dieting rich in foods like tomatoes, carrots, avocados, grapefruit, red grapes, broccoli, garlic, raspberries, nuts, cabbage, and figs Detecting cancer - An endoscope is often used to screen for colon cancer - A camera is on the end to send back images to see if anything is suspicious - Forceps can be attached to remove a small sample of tissue (biopsy) to test more thoroughly - X-rays are used to detect cancers in tissues, bones, and some organs, like the lungs - X-rays can actually cause damage to DNA and are known to be a carcinogen - They’re especially damaging to fetus in women who are pregnant (and so they use ultrasounds) - MRI (magnetic resonance imaging) uses radio waves and a strong electric field to create images of body tissue - Mri can be used to see things that regular x-rays can’t  - Computers assemble a lot of flat images to create a 3-D model - After the cancer is detected of suspected, A sample of tumour cells may have to be removed surgically (known as ‘taking a biopsy” - Cancer cells are often irregularly shaped and may be smaller or larger than the surrounding cells - Experienced medical professionals can identify cancer cells just by looking at them’ Treatment Surgery: If the tumour is accessible and contained, removal could be the safest option Chemotherapy: A drug treatment that kills cells that have a short life cycles (cancer cells) Radiation: A beam of high frequency radiation that damages the DNA of freshly made cancer cells so they can no longer undergo mitosis properly Specialized cells - A cell that can perform a specific function - Specialized cells have physical and chemical differences which allow them to perform one specific job very well - Both animal cells and plant cells show a variety of specialization Stem cells and differentiation - A stem cell is an unspecialized cell that can divide to form a specialized cell - There are 2 types of stem cells 1) Embryonic stem cells - We all start as 1 cell, that cell divides and specializes 2) Adult/Tissue stem cells - Found among differentiated cells in a tissue or organ - Can renew itself and can differentiate to yield some or all of the major specialized cell types of the tissue or organ - The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found - Adult stem cells have been identified in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and testis Uses of stem cells Increase understanding of Diseases Regeneration By watching stem cells mature into cells in bones It can generate healthy cells to replace diseased heart muscle, nerves and other organs and tissue, cells (regenerative medicine). Stem cells can be researchers and doctors may better understand guided into becoming specific cells that can be how diseases and conditions develop used to regenerate and repair diseased or damaged tissues in people Drug developments It can help test drugs for safety and effectiveness. Before using new drugs in people, some types of stem cells are useful to test the safety and quality of investigational drugs. The hierarchy of structure in animals: Cells ↓ Tissues ↓ Organs ↓ Organ system Tissues - A group of specialized cells that work together - Examples: muscles, skin, connective tissue Animal tissue types Type Example Description Function Epithelial tissue - Skin Thins sheets of tightly - Protection from - Lining of the packed cells covering dehydration digestive system surfaces and living internal - Low-friction organs surfaces Connective tissue - Bone Various types of cells and - Support - Tendons fibres held together by a - Insulation - Blood liquid, a solid, or a gel, known as a matrix Muscle tissue - Muscles that make Bundles of long cells called - Movement bones move muscle fibres that contain - Muscles surrounding specialized proteins capable the digestive tract of shortening or contracting - Heart Nerve tissue - Brain Long, thin cell with fine - Sensory - Nerves in sensory branches at the ends capable - Communication organs of conducting electrical within the body impulses - Coordination of body functions Organs - Some common examples are; heart, brain, liver, lungs, pancreas, kidney, skin, gallbladder, small and large intestine, appendix, stomach, bladder, etc - Organs are a structure in the body made up of several different cells and tissues that is specialized to perform a certain role - Example; the heart is a specialized muscle that is designed to put blood to the body - Organ systems is a group of organs that work together Systems The digestive system What is the digestive system - The digestive system is a group of organs that work together to break down food - During digestion these large molecules are broken down into smaller molecules of nutrients - These nutrients can then pass into the blood where they are used by the body cell Macronutrients - Carbohydrates (sugars) - Lipids (fats) - Proteins Structure of the digestive system Mouth - Food is chewed and mixed with saliva - Teeth help break the food down into smaller chunks - This is known as a mechanical digestion (physical) Salivary glands - Saliva is 99.5% water. It also has digestive enzymes (accessory organ) - Lubricating mouth - Amylase (to digest starches) Esophagus - Food passes down this tube from the mouth to the stomach - Uses peristalsis to move the food (the name of the process Stomach - Mixes food with digestive juices, stomach acid and enzymes - Stores food - Physically mixes the food Liver - Filters blood (accessory organ) - Gets rid of toxins - Makes bile (breaks down fat) Gallbladder - Stores bile for release (accessory organ) Pancreas - Produces enzymes (digests certain things) (accessory organ) - Produces insulin (manages blood sugar) Small intestine - Absorbs nutrients (about 90% of the food we eat) - Nutrients pass from here to the bloodstream Large intestine - Sucks out moisture from ‘waste’ (poop) - Houses bacteria - Makes vitamins B and K Pyloric valve - Separates stomach and small intestine Rectum - Holding area for the poop Anus - Door to control poop leaving (in and out) The circulatory system What is the circulatory system - Blood’s transportation system - Includes heart, blood, blood vessels - Heart acts like a pump to transport and regulate blood flow - That happens through a series of blood vessels; arteries, veins, capillaries Main functions - Transfers nutrients - Transfers oxygen - Gets rid of carbon - Gets rid of waste Types of blood vessels and parts of the heart Arteries - Carries blood away from the heart - The blood in the arteries is under very high pressure - Has thick outer walls (thick layers of muscles and elastic fibres) - Oxygenated except for pulmonary artery Veins - Carries blood to the heart - The blood in the veins is under very low pressure - Has thin walls (thin layers of muscle and elastic fibres) - Deoxygenated except for pulmonary veins - Has one-way valves in them to keep the blood moving in the correct direction Capillaries - Capillaries are the smallest blood vessel in your body - Around one cell thick - Oxygen and carbon dioxide flow in and out of capillaries by process of diffusion Atrium Upper chambers of the heart that receive blood. RIght atrium gets oxygen poor blood from the body. while the left atrium gets oxygen rich blood from the lungs. Ventricle The lower chambers of the heart that pump blood out. the right ventricle sends oxygen poor blood to the lungs, and the left ventricle pumps oxygen rich blood to the body Valve Flops of tissue in the heart that ensure blood flows in one direction, preventing backflow Septum A wall of muscle that divides the heart into left and right sides, separating oxygen rich blood from oxygen poor blood Oxygenated blood - Blood that contains oxygen - Mainly found in arteries - Pulmonary artery (lungs) Deoxygenated blood - Blood that does not contain oxygen - Mainly found in veins - Pulmonary veins Heart - The heart is a double pump - 1) blood is pumped to the lungs and returns to the heart - 2) blood is pumped to respiring muscles and back to the heart again 1. Deoxygenated blood is pumped from the heart ot the lungs 2. The blood receives oxygen and is pumped back to the heart 3. The oxygenated blood is then pumped to the rest of the body 4. The oxygen leaves the blood to be used for respiration in the body and the blood goes back to the heart Respiratory system Organs - Nose - Pharynx - Trachea - Bronchi - Lungs – alveoli (*the bronchi are broken down into smaller tubes until they hit the alveoli, which is a small sac where gas exchange occurs) Function of parts of the system Nasal cavity - Opening for gasses - Filters air - Moistions air Pharynx - The thorat Larynx - Speech - Vocal chords Trachea - Airway tube - Cartilage ring to not collapse Bronchus - Smaller airway Bronchioles - Even smaller airway that lead to aleveoli Aleveoli - Transfers O2 in CO2 out of capillaries Diapharagm - Muscle for breathing in and out Other systems Endocrine system Excretory system - System of glands (pituitary, - Consists of kidneys, ureters, urinary hypothalamus, thyroid, pancreas, ovaries, bladder, urethra, skin testes) each of which secretes a type of - Fillers waste products from the blood and hormone directly into the bloodstream maintains the proper levels of water and - Hormones regulate various human electrolytes in the body functions, including metabolism, growth - As blood flows through your kidneys, and development, tissue function, and wastes like urea, carbon dioxide, and mood water by fillers (called nephrons) - Information signal system like the - The wastes turn into urine (pee) nervous system - Urine moves out of the kidneys down to - Effects are slow to initiate and prolonged the ureters to the urinary bladder (which is in their response, lasting from a few hours where it is stored until it be be up to a few weeks ‘eliminated’) - Skin is part of the excretory system because it excretes water, salt and urea in sweat Integumentary system Lymphatic system - The most visible organ system is the - Part of the circulatory system, comprising integumentary systems a network of conduits called lymphatic - Made up of skin (epidermis and dermis) vessels that carry a clear fluid called and accessory structures (horns, antlers, lymph (essentially recycled blood plasma) hooves, quills, claws, hair and nails) toward the heart - Various glands, including sweat glands, Lymphatic system has multiple interrelated sebaceous (oil) glands, and scent glands functions including: are also part of the integumentary system - Absorbing and transporting fatty acids - Skin glands produce fluids that serve and fasts from the digestive system different purposes - Transporting white blood cells to and - Eg. sweat glands secrete sweat from the lymph nodes into the bones - Evaporation of sweat cools the body when - Transporting antigen-presenting cells it is overheated (APCs) to the lymph nodes where an - Sebaceous glands produce oil that immune response is stimulated lubricates, waterproofs, and helps prevent skin infections Muscular system Nervous system - Consists of skeletal, smooth, and cardiac - Consists of a network of specialized cells muscles called neurons that controls body - It works with the skeletal system to permit functions and coordinated responses and movement of the body, maintain posture, activities and circulate blood throughout the body - In most animals the nervous system - The muscular system in vertebrates is contains the brain, spinal cord, nerves, controlled through the nervous system, and retina although some muscles (cardiac muscle) - Neurons send signals to other cells as can be completely autonomous electrochemical waves travelling along  thin fibers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses - A cell that receives a synoptic signal may be excited, inhabited, or otherwise modulated Reproductive system Skeletal system - System of organs within an organism - Consists of both fused and individual which work together for the purpose of bones supported and supplemented by reproduction ligaments, tendons, muscles and cartilage - The major organs of the reproductive - It serves as a scaffold which supports system includes the external genitalia organs, anchors muscles, protects organs (penis and vulva) as well as a number of such as the brain, lungs, and heart, and internal organs including the testicles and allows movement ovaries - At birth a newborn baby has over 300 - Many non-living substances such as bones, whereas on average an adult fluids, hormones, and pheromones are human has 206 bones also important accessories to the - The difference comes from a number of reproductive system small bones that fuse together during growth Animal Organ System Basic Function Circulatory Transports oxygen, nutrients, wastes, etc within the body Digestive Digests food; absorbs nutrients; eliminates wastes Endocrine Controls growth, development, and metabolism Excretory Filters waste products from the blood Integumentary Covers and protects the body Lymphatic Protects the body from disease Muscular Provides movement and blood circulation (digestion) Nervous Controls and coordinates body functions Reproductive reproduction Respiratory Gas exchange (oxygen in and carbon dioxide out) Skeletal Supports and protects the body; allows movement Systems working together - When you exercise or play sports you are removing your muscles - As a result, your heart rate and breathing increases because your muscles need more oxygen and energy - This is evidence that your respiratory and circulatory systems are working together to respond to the needs of your muscles Interactions with the circulatory system - Our body systems function in a way to maintain homeostasis (means ‘steady state’) - Generally, this means that there is an acceptable range of physical and chemical conditions in which body cells, tissues, and organs can operate efficiently Circulatory and respiratory systems How do these two systems work together?: - Gas exchange is able to occur at the surface of the alveoli at the edges of the lungs that are surrounded by blood capillaries - Oxygen (O2) enters the blood and carbon dioxide (CO2) exits at the point of contact between the alveoli and capillaries Respiratory → circulatory → muscular How do these three systems work together? - Oxygen enters via the lungs and heads into the bloodstream via the capillaries surrounding the alveoli in the lungs - The blood then travels to a muscles system and if it needs oxygen, the oxygen heads to the muscles when they’re in contact with capillaries - The muscles in turn diffuse CO2 into the blood through contact with capillaries and it exits via the lungs Circulatory and digestive system How do these two systems work together? - Capillaries surround the digestive system - As soon as nutrients are released from food, they diffuse through the organs, into capillaries, to be carried through the body by the blood Digestion → nutrients → diffuse to blood → go where required Cellular respiration - The basic process that drives how living organisms access energy is respiration - C6H12)6+602→6CO2+^ H2)+energy Plant organs and organ systems Plant organs Plants are much less sophisticated than animals and only contain four organs; - Roots - Leaves - Stem - flower/fruit Part of the reason for this is that they don’t have to move around to gather nutrients due to their ability to undergo photosynthesis (sedentary-not very active) Roots Stem Leaf - Anchors the plant into the (circulatory and skeletal - The tissues in a leaf work together soil which permits the system) to accomplish photosynthesis plant to grow above the Performs two major - Photosynthesi is a chemical reaction soil without toppling over functions: in which carbon dioxide and water - Collects water from the - It transports water are converted into sugar and oxygen surrounding soil and and nutrients (food for plants) transport it to the stem and throughout the plant - The vascular tissue carries water stores food that is made in - It supports the leaves needed for photosynthesis from the other parts of the plant and flowers root up the stem to the leaf - Different tissues in the (the tissues that make up the - The sugar produced is carried by the root work together to stem reflect these functions) vascular tissues to the rest of the accomplish these functions plant Flower - Reproductive system of the plant - The main function of the flower is to reproduce seeds through sexual reproduction - The flower contains male organs (called stamnes) which consists of a filament with an anther at the tip - The anther produces pollen, which are the ”male sex cell”. - The flower also contains female organs called pistil - It consists of the ovary, style, and stigma - Female sex cells called eggs, are located in the ovary - Then the pollen and an egg unite, the fertilized egg becomes a seed. - Some seeds are surrounded by flesh and are called the fruit - Other types of seeds have no fleshy covering but are encased in a hard shell - Like other parts of the plant, new cells are made up from meristematic tissue - As the flower structures develop, the unspecialized meristematic tissue differentiated to form the other parts of the flower, such as the sepal and the stamen Plant organ summary 4 distinct plant organs: - Roots: anchors the plant; collects water; food storage - Stem: transports water and nutrients throughout the plant; supports the leaves and flowers - Leaf: where photosynthesis occurs - flower/fruit: reproductive structure (seeds) Lab: Frog dissection Differences : 1) Human heart has 4 chambers; Frog heart has 3 chambers (2 aortas and 1 ventricle) 2) Humans only use lungs for breathing; Frogs use skin and lungs to breathe 3) Frogs don't have a diaphragm