Human Biology Course Lecture 1 Part 2 PDF

# Human Biology Course ## Introduction **Biology**: study of living organisms, and their interaction with surrounding environment. Biology contains many disciplines such as Biochemistry, Physiology, Anatomy, Histology. **Human Biology**: study of all aspects of Human including Evolution, Genetics...

# Human Biology Course ## Introduction **Biology**: study of living organisms, and their interaction with surrounding environment. Biology contains many disciplines such as Biochemistry, Physiology, Anatomy, Histology. **Human Biology**: study of all aspects of Human including Evolution, Genetics, Ecology, Anatomy and Physiology Development, Anthropology, and Nutrition. ## Characteristics of Living Organisms - Metabolism - Respond to stimuli - Reproduction and development - Homeostasis - Evolution - Organization ## Metabolism Metabolism, sum of chemical reactions that take place within each cell of living organism and that provide energy for vital processes and for synthesizing new organic material. - Anabolism processes - Catabolism processes ## Sensitivity Organisms can respond to diverse stimuli. For example, plants can grow toward a source of light. Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response. ## Reproduction and Development Single-celled organisms reproduce by budding (Yeast) or simply split into two (Bacteria). Multicellular organisms often produce specialized reproductive cells (sperm & ova) that will form new individuals. When reproduction occurs, genes are passed along to an organism's offspring. These genes ensure that the offspring will belong to the same species and will have similar characteristics, such as size and shape. All organisms grow and develop following specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species’ young will grow up to exhibit many of the same characteristics as its parents. ## Homeostasis In order to function properly, cells need to have appropriate conditions such as proper temperature, pH, and appropriate concentration of diverse chemicals. These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through homeostasis “steady state” the ability of an organism to maintain constant internal conditions. For example, an organism needs to regulate body temperature through a process known as thermoregulation. ## Evolution As a population of organisms interacts with the environment, individuals with traits that contribute to reproduction and survival in that particular environment will leave more offspring. Over time those successful traits (called adaptations ) will become more common in the population. This process, change over time, is called evolution, and it is one of the processes that explain the diverse species seen in biology. Adaptations help organisms survive in their ecological niches, and adaptive traits may be structural, behavioural, or physiological; as such, adaptations frequently involve other properties of organisms such as homeostasis reproduction, and growth and development. ## Organization Living things have multiple levels of organization. Their molecules are organized into one or more cells. A cell is the basic unit of the structure and function of living things. Single celled organisms contain structure called organelles, which allow them to be self sufficient. Militi cellular organisms body consist of cell which organized into tissue which organized into organs an organs organized into system. There are level of organization that extend beyond individual organisms. All the member of one species in particular area make population. The population of various animals and plants make community. The community of populations interacts with physical environment and form an ecosystem Finally all the earths ecosystem make up the biosphere. **Diagram** A diagram depicting the levels of organization of living things from atoms to the biosphere. The diagram shows a circular flow, starting from atoms, then moving up to molecules, cell organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and finally the biosphere. ## Microscope Cell theory time line of cell discoveries synchronous with development of microscope. Microscope has been developed from one single Lense through light microscope to electronic microscope. It is an instrument uses to enlarge specimen under examination, and give image with clear details and good resolution. **Diagram** A diagram depicting the parts of a light microscope. The different parts labeled on the microscope include: - Ocular lens(eyepiece) - Nosepiece - Objective lenses - Stage - Condenser & diaphragm - Light Source - Arm - Coarse focus - Fine focus - Base **Diagram** Two images of an animal cell, one viewed under a light microscope and one viewed under an electron microscope. The image viewed under the electron microscope shows the cell components in more detail than the image viewed under the light microscope. ## Cell Theory The cell theory is one of the fundamental theories unifying all of the biology, the theory states that: - All organisms are made of one or more cells. - All the life functions of organisms are made within the cell. - All cells come from existing cells. - The cell is basic unit of live. - Cells arise from pre-existing cells. ## Modern Cell Theory - Genetic material (DNA) is passed on from one cell to another during cell division. - All cells have the same basic chemical composition - Energy flow occurs within cells ## Classification Classification can be defined as grouping organisms according to their structural similarities. This means that organisms that share similar features are placed in one group. These groups are arranged from the largest group of organisms to the smallest group of organisms. The groups, from largest to smallest, are arranged as follows: kingdom, phylum (plural phyla), class, order, family, genus (plural genera) and species. The species is the smallest group of organisms. A species can be defined as a group of organisms with similar features, and these organisms are capable of breeding and produce fertile offspring. ## Kingdoms and Domains The largest group of living organisms is the kingdom. There are five kingdoms: prokaryotes (which includes bacteria), protoctista, fungi, plants and animals. Each kingdom is further divided into smaller groups called phyla, based on a few features that are shared by some organisms. For example, the arthropod phylum contains all the animals without a backbone that also have jointed legs and a hard covering over their body, such as insects, crustaceans and spiders. A phylum is then subdivided into classes, orders, families, genera, and finally species. **Table** | Kingdom | Phylum | Class | Order | Family | Genus | Species | |---|---|---|---|---|---|---| | Animalia | Chordata | Mammalian | Primate | Hominidae apes | Homo primitive | sapiens | **Table** | | | | |---|---|---| | **Kingdom** | **Animalia** | **All animals** | | **Phylum** | **Chordata** | **All animals with back bone** | | **Class** | **Mammalian** | **All animals with back bone Mammary gland and hair**| | **Order** | **Primate** | **Mammals with hands and feet** | | **Family** | **Hominidae apes** | **primitive humans and modern humans** | | **Genus** | **Homo primitive** | **humans and modern humans only** | | **Species** | **sapiens** | **modern humans only** | | **Scientific name:** | **Homo sapiens** | | ## Binomial System Carl Linnaeus, a Swedish botanist who lived from 1707 to 1778, introduced the hierarchical classification system. In addition to that, he gave each and every species a scientific name in Latin. The binomial system of naming species means giving organisms two names in Latin (scientific names). Linnaeus derived scientific names from the genus and the species to which organisms belong. When writing a scientific name, the genus name is written first and starts with a capital letter, and the species name is written second and starts with a small letter. The scientific name ought to be printed in italics when typed and underlined separately when handwritten. ## Scientific Methods The scientific method is a series of processes that people can use to gather knowledge about the world around them, improve that knowledge, and attempt to explain why and/or how things occur. This method involves making observations, forming questions, making hypotheses, doing an experiment, analysing data, and forming a conclusion. Every scientific experiment performed is an example of the scientific method in action. ## Observation Observation is anything that is detected through human senses of touch, smell, taste, or hearing. In addition, we can extend and improve our own senses with instruments such as thermometers and microscopes. Other instruments can be used to sense things that human senses cannot detect at all, such as ultraviolet light or radio waves. ## Hypothesis A hypothesis is a possible answer to a scientific question, it must be based on scientific knowledge. A hypothesis also must be logical, and useful in science, a hypothesis must be testable. In other words, it must be possible to subject the hypothesis to a test that generates evidence for or against it, and it must be possible to make observations that would disprove the hypothesis if it really is false. ## Experiment An experiment is a special type of scientific investigation that is performed under controlled conditions. Like all investigations, an experiment generates evidence to test a hypothesis. An experiment generally tests how one particular variable is affected by some other specific variable. The affected variable is called the dependent variable or outcome variable. The variable that affects the dependent variable is called the independent variable. It is also called the manipulated variable because this is the variable that is manipulated by the researcher. Any other variables (control variable) that might also affect the dependent variable are held constant, so the effects of the independent variable alone are measured. ## Data Analysis There are two basic types of statistics: descriptive statistics and inferential statistics. Both types are important in scientific investigations. An example of a statistical hypothesis test is a t-test. It can be used to compare the mean value of the actual data with the expected value predicted by the hypothesis. Alternatively, a t-test can be used to compare the mean value of one group of data with the mean value of another group to determine whether the mean values are significantly different or just different by chance. ## Descriptive Statistics Descriptive statistics describe and summarize the data. They include values such as the mean, or average, value in the data. Another basic descriptive statistic is the standard deviation, which gives an idea of the spread of data values around the mean value. Descriptive statistics make it easier to use and discuss the data and also to spot trends or patterns in the data. ## Conclusion If the data support the hypothesis, then the hypothesis is accepted. If the data do not support the hypothesis, then the hypothesis is rejected. As long as an experiment is well designed and executed. The experiment is still valid even when the hypothesis is rejected ## Communicate the Results Scientists may communicate their results in a variety of ways. The most accurate way is to write up the investigation and results in the form of an article and submit it to a peer-reviewed scientific journal for publication. The editor of the journal provides copies of the article to several other scientists who work in the same field. These are the peers in the peer-review process. The reviewers study the article and tell the editor whether they think it should be published, based on the validity of the methods and significance of the study. The article may be rejected outright, or it may be accepted, either as is or with revisions. Only articles that meet high scientific standards are ultimately published. ## Chemistry of Live Matter is anything that takes up space and has mass. An element is a pure substance. It cannot be broken down into other types of substances. Each element is made up of just one type of atom. ## Matter and Element Matter is anything that takes up space and has mass. An element is a pure substance. It cannot be broken down into other types of substances. Each element is made up of one type of atom. ## Periodic Table There are almost 120 known elements. the majority of elements are metals. Examples of metals are iron (Fe) and copper (Cu). Metals are shiny and good conductors of electricity and heat. Nonmetal elements are far fewer in number. They include hydrogen (H) and oxygen (O). They lack the properties of metals. The most important element to the living things is Carbon (C). **Diagram** Periodic Table of the Elements ## Atoms An atom is the smallest particle of an element that still has the properties of that element. Every substance is composed of atoms. Atoms are extremely small. An atom is composed of many subatomic particles, protons, neutrons, and electrons. **Diagram** Diagram of an atom showing the structure of nucleus (protons and neutrons) and the revolving electrons around the nucleus. ## Nuclear Forces If the number of protons and electrons in an atom are equal, then an atom is electrically neutral because the positive and negative charges cancel out. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion. The negatively charged electrons of an atom are attracted to the positively charged protons in the nucleus by a force called electromagnetic force, for which opposite charges attract. Electromagnetic force between protons in the nucleus causes these subatomic particles to repel each other because they have the same charge. However, the protons and neutrons in the nucleus are attracted to each other by a different force, called *nuclear force*, which is usually stronger than the electromagnetic force repelling the positively charged protons from each other ## Compound A compound is a unique substance that consists of two or more elements combined in fixed proportions. This means that the composition of a compound is always the same. The smallest particle of most compounds in living things is called a molecule. **Diagram** Diagram showing the arrangement of atoms in different chemical compounds: - Water (H₂O) - Ammonia (NH₃) - Carbon dioxide (CO₂) - Hydrogen peroxide (H₂O₂) ## Types of Chemical Bonds **Diagram** Diagram showing the difference between covalent and ionic bonds. Covalent bonds are formed by sharing electrons, while ionic bonds are formed by donating electrons. - **Non polar covalent bond**: Methane one carbon atom and four hydrogen atoms - **Polar covalent bond**: - **Hydrogen bond**: - **Ionic bond**: ## Hydrogen Bond A hydrogen bond is an intermolecular and intramolecular attractive force in which a hydrogen atom that is covalently bonded to a highly electronegative atom is attracted to a lone pair of electrons on an atom or a partially negative atom in a neighbouring polar molecule. Hydrogen bonds are also found intramolecularly in the tertiary and quaternary structures of protein and DNA strands. Hydrogen bonding occurs only in molecules where hydrogen is covalently bonded to one of three elements: fluorine, oxygen, or nitrogen. These three elements are so electronegative that they withdraw the majority of the electron density in the covalent bond with hydrogen, leaving the H atom very electron-deficient. The H atom nearly acts as a bare proton, leaving it very attracted to lone pair electrons on a nearby atom. ## Chemical Compounds The compounds found in living things are known as *biochemical compounds*. *Biochemical compounds* make up the cells and other structures of organisms and carry out life processes. Carbon is the basis of all biochemical compounds, for carbon has ability to form stable bonds with many elements, including itself. This property allows carbon to form a huge variety of very large and complex molecules. ## Carbohydrates Carbohydrates include sugars and starches. These compounds contain carbon, hydrogen, and oxygen atoms. Functions of carbohydrates in living things include providing energy to cells, storing energy, and forming certain structures, such as the cell walls of plants. The monomer that makes up large carbohydrate compounds is called a monosaccharide. The sugar glucose, is a monosaccharide. It contains six carbon atoms (C) and several atoms of hydrogen (H) and oxygen (O). Thousands of glucose molecules can join together to form a polysaccharide such as starch. ## Monosaccharides Sugars are short-chain, soluble carbohydrates, which are found in many foods. Their function in living things is to provide energy. The simplest sugars consist of a single monosaccharide. They include glucose, fructose, and galactose. Glucose is a simple sugar that is used for produce energy by cells of living things. Fructose is a simple sugar found in fruits, and galactose is a simple sugar found in milk. **Diagram** Diagram showing the structures of the monosaccharides glucose, fructose, and galactose.