Unit 1: The Basis of Life (PDF)

UNIT 1: THE BASIS OF LIFE As far as we know the Earth is the only planet in our solar system on which life is developed. Our planet meet the conditions required for living beings to develop: - Our atmosphere protects us from the ultraviolet solar rays. In addition,...

UNIT 1: THE BASIS OF LIFE As far as we know the Earth is the only planet in our solar system on which life is developed. Our planet meet the conditions required for living beings to develop: - Our atmosphere protects us from the ultraviolet solar rays. In addition, the Earth has mild temperatures due to the greenhouse effect. The presence of certain gases in the atmosphere, such as carbon dioxide, which retains the Sun heat and maintain an average constante temperature of 15 degrees. - Thanks to that average temperature there is water in a liquid state on the Earth. Properties of water are vital for any form of life. - The air in the atmosphere provides oxygen and carbon dioxide which is vital for respiration and photosynthesis. - Geosphere provides a layer (magnetic field) which protects us from dangerous solar winds. https://m.youtube.com/watch?v=xLvZXKzIjhA 1. Biomolecules: Biomolecules are the molecules that compose living beings. There are two types: - Organic biomolecules: ❏ Carbohydrates or saccharides: The majority of them are in charge of storing and transporting energy but others are structural components like cellulose. ❏ Lipids: They perform many functions but the main ones are: ❏ Fats and oils store energy. ❏ Waxes are produced for protection. ❏ Proteins: Their most important functions are: ❏ Give structure to the cells ❏ Regulate chemical reactions like enzymes. ❏ Nucleic acids: There are two types, they store the information of living beings.  ❏ DNA: It stores all the necessary information for the functioning and development of living things. It’s found in the nucleus. ❏ RNA: It participates in the synthesis of proteins. It’s found in the cytoplasm. - Inorganic biomolecules: - Water: It is used to carry out all chemical reactions. It’s also needed to transport substances and to regulate body temperature. - Mineral salts: They form the solid structure of living beings such as skeletons. They are also involved in chemical reactions; they are necessary for the transmission of nervous impulses. 2. The CELL Cells are the structural and functional units of all living beings.There are two types: prokaryotic and eukaryotic cells. Do you know the differences between them? Watch the video: https://www.youtube.com/watch?v=RQ-SMCmWB1s Differences between prokaryotic and eukaryotic cells. - Prokaryotes were the first form of life. Scientists believe that eukaryotes evolved from prokaryotes around 2.7 billion years ago. - The primary distinction between these two types of organisms is that eukaryotic cells have membrane-bound organelles and prokaryotic cells do not. - Prokaryotes are bacteria, they are unicellular organisms so they usually have motion systems such as flagella and cilia. On the contrary, eukaryotes could be pluricellular so they normally don't have a motion system. - Prokaryotes have bacterial wall. Watch the next page: http://learn.genetics.utah.edu/content/cells/insideacell/ - Bacterial Wall: It’s totally different to the cell wall. Only bacteria have it. - Cell membrane: It’s a layer which encloses the cell and regulates the substances exchanged between the inside and the outside of the cell. - Cell Wall: A thick, rigid layer which provides support and protection. It’s only in plant cells. - Cytoplasm: It’s the liquid which fills most cells. It contains all the membrane-bound organelles, but only in eukaryotic cells, whereas in prokaryotic cells it contains all the different elements. Remember cytosol and cytoskeleton (https://www.youtube.com/watch?v=7pR7TNzJ_pA) - The genetic information is in the nucleus of the cells (eukaryotic cells) or in the cytoplasm (prokaryotic cells), and it transmits hereditary information from one generation to the next. - Nucleus: Only eukaryotic cells have nucleus. It stores genetic information. In prokaryotic cells this material is loose in the cytoplasm. - Ribosomes: They make or synthesise proteins. In prokaryotic cells, ribosomes are loose in the cytoplasm. In eukaryotic cells, they are in a wall of a membrane-bound called Rough Endoplasmic Reticulum. - Rough Endoplasmic Reticulum: This is where proteins formed in the ribosomes are stored and processed. - Smooth Endoplasmic Reticulum: This membrane-bound organelle transports and stores lipids. - Golgi Body: This membrane-bound organelle eliminates the cellular wastes. It adapts the proteins in order to realize the necessary functions. Proteins can be mixed with lipids or carbohydrates. - Lysosomes: They do the process of cellular digestion. They break down macromolecules to supply the needs of the cell. - Vacuoles:They are sacs filled with water. - Centrioles: They control the cellular movement. - Mitochondrion: It´s a double membrane-bound organelle responsible for cellular respiration (Process to obtain chemical energy from organic matter). The basic equation for respiration is: Glucose + O2 ====== H2O + CO2 + chemical energy (Stored in ATP molecule) Watch the video: https://www.youtube.com/watch?v=aWNc9sE5Jpg Endosymbiotic Theory: https://www.youtube.com/watch?v=8oSqXAwLsZc  - Chloroplast: Responsible for photosynthesis (Process to obtain organic matter from inorganic matter). These organelles are only found in plant cells and they are bounded by a double membrane but larger than mitochondrion. (See the picture). The equation for photosynthesis is: Solar energy + H2O + CO2 ========== Glucose + O2 If you want to study the differences between plant and animal cells, watch https://youtu.be/MWz4ptP_QEU (It´s suggeted by one of your mates) Watch the video to review all the membrane-bound organelles: 3. Tissues: The term tissue is used to describe a group of cells that are similar in structure and perform a specific function. Tissues are organized into four broad categories based on structural and functional similarities. These categories are epithelial, connective, muscle, and nervous. The primary tissue types work together to contribute to the overall health and maintenance of the human body. Thus, any disruption in the structure of a tissue can lead to injury or disease. The Four Primary Tissue Types Epithelial tissue refers to groups of cells that cover the exterior surfaces of the body, line internal cavities and passageways, and form certain glands. Connective tissue, as its name implies, binds the cells and organs of the body together. Muscle tissue contracts forcefully when excited, providing movement. Nervous tissue is also excitable, allowing for the generation and propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body https://www.youtube.com/watch?v=nn9jEUU4hxs  Tissue Definition Types Function Epithelial Tissues that cover the Ephithelium Lines the surface of the body and surface of the body and line tissues hollow cavities. internal cavities and various organs. Cells are stacked Glandular Produces and secretes together with almost no epithelium substances. We can find cells that intercellular substance combine to form glands, these between them. could be exocrine and endocrine glands. Muscle It is responsible for Striated muscle Allows the skeleton to move. It’s producing movement and movement is quick and voluntarily. force. It´s a soft tissue that can contract. Their cells are Cardiac muscle Keeps the heart pumping. It called muscle fibres. contracts involuntarily. Smooth muscle Helps organs to move. It contracts slowly and involuntarily. Nervous Nervous tissue makes up Neurons It generate and transfer impulses. our nervous system. Glia cells They provide nutrients and protect neurons. Connective They support, unify and Conjunctive Its function is to support or connect other tissues and tissue connect organs. Its matrix organs. The extracellular presents different types of fibres, matrix is the material part of such as collagen, created by cells tissue that doesn’t part of known as fibroblasts. any cell. Adipose tissue It’s composed of cells that accumulate fat known as adipocytes. Its main function is to store energy. Cartilaginous It’s a firm but elastic tissue that tissue protect joints of the bones for example. These tissues are formed by cells known as chondrocytes. Bone tissue This is a rigid tissue that supports the body and protects its organs. It’s made up of minerals, such as Calcium which makes it hard. Bone cells are called osteocytes. Blood tissue It transports nutrients and oxygen to the cells. Blood tissue has a fluid matrix known as blood plasma. Blood contains red blood cells (erythrocytes), white cells (leucocytes) and platelets. 4. Organs and Systems in the human body: 4.1. Systems involved in the nutrition function: Nutrition in animals (Heterotroph multicellular organisms) is composed by different systems to obtain the energy and matter, in order to perform cellular metabolism. a. Digestive system: Breaks down food into nutrients which are used for energy and growth. b. Respiratory system: Intake of oxygen (to perform cellular respiration in each cell, remember unit 1) c. Circulatory system: Connects all cells in the organism. d. Excretory system: Waste products of metabolism and other non-useful materials are eliminated from an organism. - Digestive system: Expel the waste substances from the food. - Liver: Expel some toxic from our blood - Respiratory system: Expel the dioxide carbon to the outside. - Urinary system: Clean the blood - Sweat glands: Eliminate some toxic from our blood. 4.2 Systems involved in the interaction function:In humans, the interaction function is carried out by the nervous, endocrine, muscular and skeletal systems. The nervous system receives information from the outside environment and our body and generates signals, which it uses to coordinate bodily functions. The endocrine system, working in parallel with the nervous system, generates signals that induce responses in certain organs through molecules called hormones. The muscular and skeletal systems make up the locomotor system. Controlled by the nervous system, they generate movement. 4.3. Systems involved in the reproduction function: In humans, the reproduction function is carried out by the male and female reproductive systems. The female reproductive system produces the female gametes and nurtures and protects the embryo during its development. The male reproductive system produces the male gametes.