Edo State University BIO 101 General Biology Past Paper PDF

EDO STATE UNIVERSITY UZAIRUE Department of Biological Sciences FACULTY OF SCIENCE Plant Biology and Biotechnology Unit BIO 111: GENERAL BIOLOGY 1 Lecture by...

EDO STATE UNIVERSITY UZAIRUE Department of Biological Sciences FACULTY OF SCIENCE Plant Biology and Biotechnology Unit BIO 111: GENERAL BIOLOGY 1 Lecture by: D R. ( M REDO S.STATE ) UNIVERSITY G O D DUZAIRUE- I D I BIO T 101E –SGENERAL I R OBIOLOGY ENOYOZE 1  Class rules Class attendance is mandatory. 10 minutes lateness is maximum grace for any class. University dress codes must be strictly adhered to when coming to class. Defaulters would be sent back to the hostel. No noise making would be tolerated in class. No use of phones, ear-pierce or any other media device in class. No receiving of calls. Attendance is the pre-requisite for exams. Note taking in class is mandatory (notes would be marked). Be prepared for test at any time. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 2  Mode of Assessment Continuous Assessment (30 marks) Term paper – 10 Presentation – 10 Test – 10 Examination (70 marks) EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  COURSE CONTENT Cell structure and organisation, functions of cellular organelles. Characteristics and classification of living things. Chromosomes, genes; their relationships and importance. General reproduction. Interrelationships of organisms (competitions, parasitism, predation, symbiosis, commensalisms, mutualism, saprophytism). Heredity and evolution (introduction to Darwinism and Lamarkism, Mendelian laws, explanation of key genetic terms). Elements of ecology and types of habitat. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  CHARACTERISTICS AND CLASSIFICATION OF LIVING THINGS EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  INTENDED LEARNING OUTCOMES At the end of lectures, students should be able to: explain cells structures and organisation; summarize functions of cellular organelles; characterize living organisms and state their general reproduction; describe the interrelationship that exists between organisms; discuss the concept of heredity and evolution; and enumerate habitat types and their characteristics. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Week 1 Intended Learning Outcomes At the end of this lecture, students should be able to: Explain what biology is. Define basic concepts relating to biology. Describe the characteristics of living things. Differentiate between living and non-living things. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is biology? EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is biology? What do the Atoms and molecules different things identified have in What makes the animals common? and plants different from the other things? EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is biology? Biology is the science that deals with the study of life, the interrelationship between diverse forms of living things and their environment. ▪ Bios meaning ‘life’ ▪ Logos meaning ‘study or discourse’ Life represents the presence of the processes that make a thing living. These processes are referred to as the characteristics of living things. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Biology Biology is the study of living things. It encompasses the cellular basis of living things, the energy metabolism that underlies the activities of life, and the genetic basis for inheritance in organisms. Biology also includes the study of evolutionary relationships among organisms and the diversity of life on Earth. It considers the biology of microorganisms, plants, and animals, for example, and it brings together the structural and functional relationships that underlie their day-to-day activities. Biology draws on the sciences of chemistry and physics for its foundations and applies the laws of these disciplines to living things. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Characteristics of Living Things 1. Complex organization ▪ Life’s organization starts with interactions among atoms. ▪ Atoms join to form molecules. The molecules of life (lipids, proteins, DNA, RNA and complex carbohydrates) become organized to form a cell. ▪ The cell is the basic structural and functional unit of organisms. It is the smallest organized unit in living things that is able to carry on all activities necessary for life. Cells survive and replicate themselves using energy, raw materials, and information in their DNA. Some cells live and reproduce independently. Others do so as part of multicellular organism. ▪ An organism is an individual that consists of one or more cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is the difference between an atom, element and molecule? EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ▪ In most multi-celled organisms, cells make up tissues which are typically specialized and organized in a particular pattern. An organ is an organized array of tissues that collectively carry out a particular task or set of tasks. ▪ Population is a group of single-celled or multi-celled individuals of a species in a given area. ▪ A community includes all populations of all species in a specified area. ▪ An ecosystem is a community interacting with its physical environment through the transfer of energy and materials. E.g., sunlight and water sustain the natural community in Obudu cattle ranch. ▪ Biosphere is the sum of all ecosystems and regions of the earth crust, water and atmosphere in which organisms live in. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What makes an organism? Energy – organisms acquire and utilize energy for their basic processes. Cells – organisms are made up of cells. Information – organisms possess hereditary or genetic information, encoded in units called genes, along with information they acquire from their environment. Replication – an organism replicates itself. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 2. Metabolism Living things exhibit a rapid turnover of chemical materials, which is referred to as metabolism. Metabolism involves exchanges of chemical matter with the external environment and extensive transformations of organic matter within the cells of a living organism. Metabolism generally involves the release or use of chemical energy. Nonliving things do not display metabolism. 3. Responsiveness All living things are able to respond to stimuli in the external environment. For example, living things respond to changes in light, heat, sound, and chemical and mechanical contact. To detect stimuli, organisms have means for receiving information, such as eyes, ears, and taste buds. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 To respond effectively to changes in the environment, an organism must coordinate its responses. A system of nerves and a number of chemical regulators called hormones coordinate activities within an organism. The organism responds to the stimuli by means of a number of effectors, such as muscles and glands. Energy is generally used in the process. Organisms change their behavior in response to changes in the surrounding environment. For example, an organism may move in response to its environment. Responses such as this occur in definite patterns and make up the behavior of an organism. The behavior is active, not passive; an animal responding to a stimulus is different from a stone rolling down a hill. Living things display responsiveness; nonliving things do not. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 4. Reproduction A living thing has the ability to produce copies of itself by the process known as reproduction. These copies are made while the organism is still living. Among plants and simple animals, reproduction is often an extension of the growth process. More complex organisms engage in a type of reproduction called sexual reproduction, in which two parents contribute to the formation of a new individual. During this process, a new combination of traits can be produced. Asexual reproduction involves only one parent, and the resulting cells are generally identical to the parent cell. For example, bacteria grow and quickly reach maturity, after which they split into two organisms by a process of asexual reproduction called binary fission. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 5. Growth Growth requires an organism to take in material from the environment and organize the material into its own structures. To accomplish growth, an organism expends some of the energy it acquires during metabolism. An organism has a pattern for accomplishing the building of growth structures. During growth, a living organism transforms material that is unlike itself into materials that are like it. A person, for example, digests a meal of meat and vegetables and transforms the chemical material into more of himself or herself. A nonliving organism does not display this characteristic. The sequential stages through which individuals develop, grow, maintain themselves, and reproduce are collectively known as the life cycle of the organism. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 6. Evolution Living organisms have the ability to adapt to their environment through the process of evolution. During evolution, changes occur in populations, and the organisms in the population become better able to metabolize, respond, and reproduce. They develop abilities (changes in the DNA) to cope with their environment that their ancestors did not have. Evolution also results in a greater variety of organisms than existed in previous eras. This proliferation of populations of organisms is unique to living things. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Ecology The environment influences the living things that it surrounds. Ecology is the study of relationships between organisms and their relationships with their environment. Both biotic factors (living things) and abiotic factors (nonliving things) can alter the environment. Rain and sunlight are non- living components, for example, that greatly influence the environment. Living things may migrate or hibernate if the environment becomes difficult to live in. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  MR NIGER D Movement They change position, either by moving from place to place or by moving parts of their bodies in response to stimulus. Respiration They exchange gases within their cells and the external environment. Nutrition They take in nutrients from organic substances and mineral ions for growth and tissue repair. Irritability They respond to changes in their environment (response to stimulus). Growth They increase in size by increasing cell numbers and cell size from within, using nutrients obtained from food. Excretion They remove toxic materials, waste products of metabolism and substances in excess by chemical reactions in the cells. Reproduction They give rise to newer organisms. Death EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  STUDY QUESTIONS ? How do I differentiate a living from a non-living thing? Are viruses living or non-living? How do living things interact with other living things and their environments? What is a life cycle? List the major levels in the hierarchy of life. What do living things do with the energy they collect from the external environment? EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Assignment Read up! The cell EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  REFERENCE TEXTS Biology: The Dynamic Science Russell Hertz McMillan EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Thank you EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  CELL STRUCTURE AND ORGANISATION, FUNCTIONS OF CELLULAR ORGANELLES. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Week 2-Lecture 1 and 2 Intended Learning Outcomes At the end of this lecture, students should be able to: Understand basic cell concepts Draw and label structures of the plant and animal cells Describe the organization, functions, chemical and physical characteristics of cells and organelles EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Discovery of Cell Marcello Malpighi (1661), found that plants consist of separate structural units “utricles”. Robert Hooke (1665), used a crude microscope to examine the structure of cork (a bark tissue from an oak tree). The instrument magnified objects to just 30× (30 times) their normal size, but it allowed Hooke to see something extraordinary. In the cork, he observed small, pore-like (box-like) compartments, forming a honey comb structure. He named it as cells (Latin cellula-a hallow space). He published his results in his book ‘Micrographia’. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Antony van Leeuwenhoek (1674) Soon after Hooke published his results, Anton Van Leeuwenhoek succeeded in developing much more powerful microscopes, some capable of magnifications up to 300x. Leeuwenhoek was able to inspect water samples of pond water and made the first observations of human blood cells, and of sperm cells. By the early 1800s after several studies on organisms and their internal components enough data was gathered to safely make the conclusion that all organisms consist of cells. He became the father of Microbiology. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 ❖Nehemiah Grew (1682), discovered that cells in the forms of cavities with cellulose walls were in different plants. He wrote The Anatomy of Plants. ❖H. J. Dutrochet (1824), expressed the idea of individuality of cells i.e., cells were not just spaces between a network of fibres, but these were separate and separable units. ❖Robert Brown (1833) named the cell nucleus. ❖Robert Remak (1855) discovered cell division and confirmed the existence of plasma membrane. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  THE CELL THEORY The cell theory is a widely accepted explanation of the relationship between cells and living things. This theory was proposed by Matthias Schleiden and Theodore Schwann in 1839. They described that all organisms are composed of similar units of organization, called cells. In 1838 Schleiden found that all plant cells have basically similar structure. Schwann (1839) observed that animal cells differ from plant cells in lacking cell wall but are otherwise similar amongst themselves. He declared that all animals and plants are made up of cells. Schleiden (1838) summarized his observations into three conclusions about cells: i. The cell is the unit of structure, physiology, and organization in living things. ii. The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. iii. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation). Rudolph Virchow (1858) states that "Omnis cellula e cellula“, meaning that the new cells arise from pre-existing cells only. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 The main features of cell theory as known nowadays are: ❑All living organism are composed of cells. Therefore cell is structural unit of living organisms. ❑All cells arise from the pre-existing cells of similar type. Thus cell is a unit of heredity. ❑All cells are basically alike in chemical composition and metabolic activities. ❑The function of an organism as a whole is the result of the activities and interactions of its cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  The largest cell is the ostrich Cell size egg 170mm 130mm Cell size varies widely in various plants. The size varies from micron to millimeter (a micron is a one thousandth part of a millimeter). The smallest cells are found in bacteria- the cell of Mycoplasma laidlawii with a diameter of about 0.1 - 0.15 micron. In plants the longest cells are fibres producing e.g. Jute, Cotton, ramie, which are about 55 cm long. A single celled alga Acetabularia measures about 10 cm in height. Mycoplasma laidlawii EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Acetabularia  Cell shape The shape of the cells varies with their position in plants. It can be polygonal, spherical, elliptical, spindle-shaped, cuboidal, plate-like or irregular. In multicellular plants cell shape also depends on their location and nature of function. The cell shapes are influenced by the surface tension and viscosity of the protoplasm, pressure exerted by the surrounding cells and the rigidity of cell membrane. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Cell types Two types of living cells were recognized in plants by Dougherty (1957). This division is based on internal complexity or morphology. Prokaryotic cell (pro = primitive, karyon = nucleus) : This type of cells have:- a) A organized nucleus is absent in the protoplasm, i.e., the nuclear material is not bounded by nuclear membrane, nuclear reticulum, nucleoplasm and nucleolus are absent. The the nuclear materials remain diffused with cytoplasm. b) Only monera i.e. Blue green algae (Cyanobacteria) and Bacteria are prokaryotic cell known as prokaryotes. c) The genetic material contain DNA, histone absent. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Cell types contd. Eukaryotic cell (eu = true, karyon = nucleus): This type of cells have:- a) A true nucleus with a definite nuclear membrane by which nuclear material is bounded. Nucleoli present. Distinct organelles, the small structures that each perform a specific set of functions, are present within eukaryotes. b) The majority of plants are composed of eukaryotic cells. c) The genetic material contains DNA complex with histone proteins to form well-organized chromosomes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Eukaryotic cell structure (plant) EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 PLANT AND ANIMAL CELL STRUCTURE EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 PLANT AND ANIMAL CELL EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ASSIGNMENT Differentiate or make a comparison between prokaryotes and eukaryotes using the following features: i. Cell size and cell organization ii. Organelles iii. DNA iv. Synthesis of RNA and proteins v. Cell division vi. Ribosomes vii. Metabolic activity viii. Cytoskeleton ix. Chromosome EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Thank you EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 PLANT AND ANIMAL CELL EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  GENERALIZED PLANT CELL GENERALIZED PLANT CELL EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Comparison between prokaryotic and eukaryotic cells Feature Prokaryotic Cells Eukaryotic Cells Bacteria and Algae, Fungi, Plants Cyanobacteria Cell size and cell 1-10 µm: unicellular 5-100 µm: multicellular organization Organelles Few or none Nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus DNA Circular (or linear) DNA Linear DNA molecules organized in organized in a nucleoid chromosomes bounded in a nucleus Synthesis of RNA RNA and proteins RNA synthesis occur in nucleus and and proteins synthesis occur in same proteins synthesis in the cytoplasm place EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Cell division Amitosis, spindle apparatus absent Mitosis, meiosis, spindle during cell division; replicated apparatus present and DNA pulled by attachment to chromosomes pulled by it plasma membrane Ribosomes 70s (50s+20s) 80s (60s+40s) Metabolic Photosynthetic and respiratory Photosynthetic and respiratory activity enzymes are found on plasma enzymes are found on membrane chloroplast and mitochondria respectively Cytoskeleton Not present Present Chromosome Single Multiple Metabolic Anaerobic (respiration in absence Aerobic (in presence of activity of oxygen) or aerobic oxygen) EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Cell wall The cell walls of plants are generally thick, strong, porous, rigid and none living structures, which enclose the cells including the plasma membranes. The cell wall is primarily made up of cellulose and pectin, but some additional materials are deposited for specific functions: Lignin (lignification) in secondary walls of the cells of woody plant. Cutin (cutinisation) on exposed surface of cell walls as in leaf surface. Suberin (suberisation) in the secondary wall of cork cells. Silica in cell wall of grasses. Functions of Cell Wall :- Cell wall provides shape and rigidity to cell. It protects the protoplasm from external injury. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Plasma Membrane All living cells are enclosed by a selectively permeable, thin molecular layer termed as plasma membrane. Plasma membrane is composed primarily of two types of molecules—lipids and proteins. Carbohydrates occur only at the outer surface of the membrane. Functions of the Plasma Membrane The plasma membrane separates the cell from its surroundings. Protects it from changes in the chemical and physical environment. Regulates movements of molecules into and out of the cell. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Cytoplasm Cytoplasm is a homogeneous, mostly clear jelly-like liquid which lies between the nucleus and cell membrane, consisting of cytosol and the cellular organelles. 80% of the cytoplasm is aqueous and composed of ions and soluble, primarily organic, macromolecules. The 20% of the cytoplasm that is not aqueous is made up of organelles. Cytosol (hyaloplasm) is composed of water, salts, organic molecules, and the many enzymes necessary for the cell to catalyze reactions. Depending on the activity phase of the cell, the cytosol could be gel-like, thus its called cytogel. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Vacuole A vacuole is a large fluid-filled sac in the cytoplasm, bounded by a single membrane called the tonoplast. Vacuoles are filled with watery fluid termed as cell sap. It is acidic. The chemical composition of cell sap differs markedly from that of the surrounding cytoplasm. In most cases mature plant cells have single large central vacuole. So that the plant cytoplasm lies as a thin layer positioned between the plasma membrane and the tonoplast. Functions of the vacuole The vacuole stores nutrients, metabolites, pigments and waste products. Pigment anthocyans are present, which is mainly responsible for the colours in flowers. It also helps the cell get rid of waste. Turgor pressure in the vacuole drives cell growth. Opening and closing of stomata is due to changes in turgor pressure of guard cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Lysosomes Lysosomes are a single membrane bound small vesicular organelles. Shape and size of lysosome is variable. A granulated stroma and a vacuole are located inside the membrane. Lysosomes are found in fungi and root tips of cells. Lysosomes are little sacs of hydrolyzing enzymes, acid hydrolases that are used by the cell to break down food as well as debris and the by-products are used in biosynthetic activity of cells. These sacs are separate from the cell because the enzymes could destroy the cell if they were mixed with the cytoplasm. The enzymes contained in the lysosome are synthesized on rough endoplasmic reticulum and are transported to golgi body. Functions of lysosome Its functions are defense against bacteria and viruses and in destroying old and worn out organelles. They have been found occasionally to be digesting the whole cell or part of cell (autolysis or self-destruction); therefore lysosomes are called suicide bags. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Endoplasmic reticulum Some of the floating membranes in the cytosol include a network of tiny sacs, tubules and vesicles that interconnect throughout the inside of the cell. This network is called endoplasmic reticulum. Endoplasmic reticulum is of two types:- Rough endoplasmic reticulum: Its external surface carries granular structures known as ribosomes (made of protein and RNA and are actively involved in the synthesis of proteins). Smooth endoplasmic reticulum: Which has a tubular structure and no ribosomes attached to the membrane surface. Function of endoplasmic reticulum The endoplasmic reticulum near the ribosomes is responsible for moving much of the protein through its tubules to other parts of the cell and maintains the integrity of the membranes surrounding the nucleus. This is the conveyor belt of the cell. The large net work of endoplasmic reticulum provide increased surface for enzyme synthetic activity. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Ribosomes Ribosomes are small, non membranous, spherical bodies mainly found bound to the endoplasmic reticulum as well as freely scattered throughout the cytoplasm, in all types of cells. Certain organelles within the cell, chloroplast and mitochondria, have their own distinct ribosomes as well. Ribosomes always have two subunits which interlock and behave as a single entity. It is composed of approximately 60 percent ribosomal RNA (rRNA) and 40 percent protein. Ribosomes are sometimes referred to as simply RNA. Like DNA, they are long chains of amino acids, but their base pairs are different and they are usually not as long as DNA. Function of ribosome:- Their main function is to produce a variety of proteins from simple genetic instructions which propagate outwards from the cellular nucleolus in the form of messenger RNA (mRNA). Ribosomes are actively involved in the protein synthesis, the process that generates organic tissue. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Golgi Apparatus The Golgi body consists of a series of cup-shaped, membrane-bounded, flattened sacs called cisternae. The Golgi body are surrounded by numerous, small, membrane-bounded vesicles. This complex is usually located close to the cell nucleus. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Function of golgi body:- The Golgi body and its vesicles function in the sorting, modifying, and packaging of macro-molecules that are secreted by the cell or used within the cell for various functions. The Golgi complex in plant cells produces pectins and other polysaccharides specifically needed by for plant structure and metabolism. Each Golgi body has two faces; -a cis face or entry face (found near ER), receives macromolecules synthesized in the endoplasmic reticulum encased within vesicles. -trans face or exit face, the modified and packaged macromolecules are transported to their destinations in the form of smaller detached vesicles. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Mitochondria Mitochondria (singular- mitochondrion) are rod-shaped, filamentous or granular structures distributed through the cytosol of most eukaryotic cells. Their number within the cell depends upon the metabolic activity of that cell, and may range from a single large mitochondrion to thousands of the organelles. Function of mitochondria:- The most important role of mitochondria is to synthesize ATP with energy supplied by the electron transport chain and a process called oxidative phosphorylation, therefore mitochondria has been called power house of the cell. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Plastids These are cytoplasmic cell organelles, primarily involved in formation and storage of soluble and insoluble carbohydrates. Plastids are two types on the basis presence or absence of pigment:- Leucoplasts (plastids without pigments):- store reserve food material colourless and occur in the cells which are not exposed to sunlight and also found in embryonic cells, meristematic cells and parenchymatous cells. Leucoplasts are the centers of starch ,oils and proteins synthesis and storage, on that basis leucoplasts are of three types (a) Amyloplasts :-filled with starch found in endo (b) elaioplasts:- store lipids and (c) aleuroplast:- store protein crystals and granules and EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Plastids Chromoplasts are plastids with pigment colours other than green, their colour is due to two pigments, carotene and xanthophyll. Yellow-to-red colored chromoplasts manufacture carotenoids, These are present in petals and fruits, imparting them different colours (red, yellow etc.). Chromoplasts may develop from chloroplasts due to replacement of chlorophyll by other pigment e.g. green tomatoes and chillies turn red on ripening due to change of chlorophyll in chloroplasts by red pigment lycopin or lycopene in tomato and capsanthin in chillies. Or from leucoplasts by the development of pigments e.g., carrots. Chromoplasts are also involved in photosynthesis. The primary function in the cells of flowers is to attract agents of pollination, and in fruit to attract agents of dispersal EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Plastids Chloroplasts are the most important type of plastid having green pigment (chlorophyll), and are typically about 10 micrometers in diameter. The plastids are made up of an outer limiting membrane and inner matrix. The outer membrane is made up of two layers of lipoprotein and separated from one another by a space known as perplastidial space. The outer layer of the double membrane is much more permeable than the inner layer, which features a number of embedded membrane transport proteins. Inner matrix of a chloroplast is differentiated into grana, where light reaction of photosynthesis takes place and the stroma where dark reaction (Calvin cycle) is completed. Grana consist of the lamellar system and stroma is non-membranous both are consist of interconnected sac like structure known as thylakoids. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Thylakoids are of two types : (1)grana thylakoid and (2) intergranal thyalkoids. The thylakoids in each granum are continuous with those in other grana through intergranal thylakoids. In the chloroplast the thylakoids are embedded, or suspended, in a matrix, the stroma, which has a somewhat granular appearance. The stroma a semi fluid colorless colloidal complex contains DNA fibrils and ribosomes, starch grains, osmophilic globules and occasional extensive crystal- like structures. The thylakoid membranes contains green pigment chlorophyll a and b carotenoids, cytochrome, ATP-synthetase, etc. Function of chloroplasts:- Chloroplasts are specialized for photosynthesis, the biological conversion of light energy absorbed by chlorophylls, the green leaf pigments, into potential chemical energy such as carbohydrates. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Nucleus The nucleus is the most prominent structure of cell. Nucleus is present only in cells of higher plants i.e. eukaryotes. Generally there is a single nucleus present in each cell, but there are exceptions also in some fungi e.g., Rhizopus etc. and algae e.g., Vaucheria more than one nucleus are present. Nucleus is absent in simpler one-celled plants -prokaryotes e.g., Viruses, bacteria and cynobacteria. The spherical-shaped nucleus, consists of a semi fluid matrix known as nucleoplasm in which one or more nucleoli, and chromatin threads are suspended. Nucleus controls cellular metabolism of cells and contains all genetic information and is able to transmit it from one generation to the other. The nucleus is the most prominent of cell. The nuclei of cell consist of four components:- EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Nuclear membrane (or envelope) :- The nuclear membrane is a double-layered semi-permeable (permitting selective molecules to pass through the membrane, into and out of the nucleus) membrane that encloses the nucleus, and separates the contents of the nucleus from the cellular cytoplasm. The membrane is perforated by numerous pores called nuclear pores which regulates the flow of molecules between the nucleus and cytoplasm, The inner nuclear membrane has a protein lining called the nuclear lamina, which binds to chromatin and other nuclear components. The nuclear membrane disintegrates during cell division or mitosis, and is reformed as the two cells complete their formation and the chromatin begins to unravel and disperse. The function of the nuclear envelope is to confine the materials necessary for DNA and RNA synthesis inside the nucleus, and controlling movement into and out of the nucleus. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Nucleoplasm :-The nucleoplasm is semi Nucleoplasm contains one or fluid that fills the interior of the nucleus. more nucleoli (singular The nucleolus and the chromatin network lie "nucleolus") , organelles that suspended in the nucleoplasm. This dense, synthesize protein-producing spherical granule found in the nucleus contains RNA (ribonucleic acid) which is macromolecular assemblies responsible for protein synthesis in the called ribosomes. cytoplasm. Nucleoplasm is distinct from cytoplasm due to the high concentration of materials like nucleotides, which are used to make DNA and RNA, and the suite of enzymes which control the DNA and RNA construction reactions. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Nucleolus :- The nucleus contains one to four densely granular region called nucleoli (singular "nucleolus"), but within each species the number of nucleoli is fixed. There is no membrane separating the nucleolus from the rest of the nucleus. The nucleolus, which is important in the formation of ribosomes, appears as a dense mass of RNA (ribonucleic acid), ribosomal RNA, chromatin, and proteins. When a cell reproduces the nucleolus disappears and reappear after cell formation. The nucleolus made of three morphologically distinct components :- i. Fibrillar centres (FC), where rRNA genes of several chromosomal loci (termed nucleolar organising regions NORs) are located; the transcription of rRNA genes (RNA synthesis on DNA template) also takes place in this region. ii. Dense fibrillar component (DFC), which surrounds the fibrillar centre which contains actively transcribing rRNA genes and nascent rRNA transcripts; and iii. Granular component (GC),which is the outermost region, which is the site of late processing events in the biogenesis of rRNAs. The rRNA which is a main element of ribosomes is created in the nucleolus, and the protein portion of the ribosome is synthesized in the cell's cytoplasm. These proteins enter the nucleus through the pores in the nuclear membrane and combine with the rRNA to form the small and large subunits. The completed subunits leave the nucleus and can be found in the cytoplasm or in an organelle known as the endoplasmic reticulum. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Chromatin and Chromosomes The nucleus contains the complex of deoxyribonucleic acid (DNA) and associated proteins, known as chromatin in the uncondensed state and as chromosomes in the condensed state. The chromatin is embedded in a clear matrix called the nucleoplasm. Chromatin are coiled strands of DNA that are found spread throughout the nucleus, that come together and coil tightly during cell replication. Each DNA strand wraps around groups of small protein molecules called histones, forming a series of bead-like structures, called nucleosomes, connected by the DNA strand. Histones are found only in nucleus and being basic protein interact strongly with deoxyribonucleic acid (DNA). The histone proteins are rich in lysine and arginine. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Heterochromatin:- During interphase chromatin becomes dispersed, even then some of its portions remain tightly coiled and are called heterochromatin. Heterochromatin is found in parts of the chromosome where there are few or no genes and are generally inactive. Euchromatin:- Loosely coiled are called euchromatin. Euchromatin is found in parts of the chromosome that contain many genes. The genes in euchromatin are active. This exposes the euchromatin and makes it available for the transcription process. Chromatin network:- These are very fine thread-like, coiled filaments uniformly distributed in the nucleoplasm. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Chromosomes: At the time of cell division, Depending upon position of the chromatin becomes thick and ribbon like Centromere chromosomes are:- and are known as chromosomes. The nucleus of a eukaryotic cell contains a number of chromosomes, which are composed of DNA and histone proteins. A typical chromosomes has two similar parts called chromatids. They are joined to each other by primary constriction or Centromere. Genes are responsible for storing and transmitting hereditary characteristics from one generation to another. A gene is the functional unit of a chromosome. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  REVIEW QUESTIONS 1. What are the various levels of organization of life? 2. Name the key scientist that contributed to the discovery of the cell and state their contributions giving illustrations where applicable. 3. State the salient points in the cell theory. 4. Draw and label the plant and animal cells appropriately. 5. State the functions of the different components of the plant and animal cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Week 4-Lecture 1 and 2 Intended Learning Outcomes At the end of this lecture, students should be able to: understand the elements of biological chemistry, state aspects of organic, inorganic and physical chemistry relevant to biology, EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Introduction Inorganic molecules: molecules without carbon atoms or relatively small carbon containing molecules e.g. minerals and atmospheric gases like CO2. Organic molecules: molecules with carbon atoms – carbohydrates, lipids, proteins and nucleic acids – are referred to as the molecules of life. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Formation and Modification of Biological Molecules Carbon atoms are known to readily share electrons, a feature that allows each carbon atom form covalent bonds with other carbon atoms or other elements. All biological molecules, either in linear or ringed structure have the carbon backbone. The structure and behaviour of organic molecules depends on the chemical properties of their functional groups. i.e. the functional group present in an organic compound would determine whether it is an alcohol, aldehyde, ketone or acid. The various functional groups are summarized as follows: EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Functional groups 1. Hydroxyl group: (-OH) they are polar thereby conferring polarity on the molecules that contain them. It’s a key component of alcohols like ethyl alcohol (ethanol), the alcohol found in beer, wine and spirits and is used in the precipitation of DNA from solution. The hydroxyl group enables an alcohol to form linkages with other organic molecules through dehydration synthesis reaction. 2. Carbonyl group: (=C=O) carbonyl groups are reactive parts of aldehydes and ketones, molecules that act as major building blocks of carbohydrates and also take part in reactions supplying energy for cellular activities 3. Carboxyl group: (-COOH) a combination of a carbonyl group and an hydroxyl group. They are the major functional groups of organic acids e.g. acetic acid. Several acids are central components of energy generating reactions in living organisms. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Functional groups 4. Amino group: (-NH2) they are major components of amino acids. They readily acts as organic bases by accepting H+ (a proton) in water solutions. 5. Phosphate group: (-OPO32-) they give molecules that contain them the ability to act as weak acids because one or both –OH groups readily releases their hydrogen. Nucleic acids DNA are linked together by phosphate groups. 6. Sulfhydryl group: (-SH) the sulfhydryl group is easily converted into a covalent linkage in which it loses its hydrogen atom as it binds. In such cases, disulphide linkages (-S-S-) are formed. Many proteins, disulfide linkage forms a sort of molecular fastener that holds proteins in their folded form or links protein subunits into larger structures. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Formation and Modification of Biological Molecules Isomers – these are compounds with the same chemical formula but different molecular structures. They are of two types: a. Enantiomers or Optical isomers – isomers that are mirror images of each other. b. Structural isomers – two molecules with atoms arranged differently. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Study Questions What is the difference between hydrocarbons and other organic molecules? What is the maximum number of bonds that a carbon atom can form? Do carboxyl groups, amino groups and phosphate groups act as acids or bases? EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  CARBOHYDRATES Carbohydrates are molecules with carbon, hydrogen and oxygen in the ratio 1:2:1. Monosaccharides contain three to seven carbons, Disaccharides are a combination of two monosaccharides, Polysaccharides are formed by three or more monosaccharides. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  LIPIDS Lipids are hydrocarbon-based, water-insoluble, nonpolar molecules. Biological lipids include neutral lipids, phospholipids and steroids. Neutral lipids are energy storing molecules, having glycerol backbone and three fatty acid chains. Phospholipids are similar to neutral lipids except that a phosphate group and a polar organic unit substitutes for one of the fatty acids. Steroids consists of four carbon rings carrying primarily nonpolar groups. They function chiefly as components of membranes and as hormones in animals. Lipids link with carbohydrate to form glycolipids and with proteins to form lipoproteins. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  PROTEINS Proteins are assembled from 20 different amino acids. Amino acids have a central carbon to which is attached an amino group, a carboxyl group, a hydrogen atom and a side group unique to each amino acid. Peptide bonds between the amino group of one amino acid and the carboxyl group of another amino acid link amino acids into chains. A protein may have four levels of structure; primary structure is the linear sequence of amino acids in a polypeptide chain; secondary structure is the arrangement of the amino acid chains into α helices, β strands and sheets or random coils; tertiary structure is the protein’s overall conformation. Quaternary structure is the number and arrangement of polypeptide chains in a protein. Proteins combine with lipids to produce lipoproteins, with carbohydrates to produce glycoproteins, and with nucleic acids to form nucleoproteins. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  NUCLEOTIDES AND NUCLEIC ACIDS A nucleotide consists of a nitrogenous base, a five-carbon sugar, and one to three phosphate groups. Nucleotides are linked into nucleic acid chains by covalent bonds between their sugar and phosphate groups. There are two main nucleic acids: DNA and RNA. DNA contains nucleotides with the nitrogenous bases adenine (A), thymine (T), guanine (G), or cytosine (C) linked to the sugar deoxyribose. RNA contains nucleotides with nitrogenous bases adenine, uracil, guanine, or cytosine linked to the sugar ribose. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  CHROMOSOMES, GENES; THEIR RELATIONSHIPS AND IMPORTANCE. GENERAL REPRODUCTION. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is a cell cycle? The cell cycle is the sequence of events that a cell undergoes as it grows and divides. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is a cell cycle? It consists of stages, including interphase (G1 – growth 1 or gap phase, S- DNA synthesis, G2 – growth 2 or gap phase 2) M phase and finally cytokinesis, where the cell physically divides into two daughter cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  What is a cell cycle? Cell division is the process by which a parent cell divides into two or more daughter cells. It's essential for growth, development, and the replacement of damaged or old cells in multicellular organisms. There are two main types: mitosis, which creates identical daughter cells, and meiosis, which produces sex cells (gametes) with half the number of chromosomes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  DEFINITIONS RELATING TO GENETICS Chromosomes: Structures within cells that contain DNA, carrying the genetic information. Humans have 23 pairs of chromosomes, with one set inherited from each parent. Gene: A segment of DNA that contains the instructions for a specific trait. Genes determine various characteristics, like eye color or height. Allele: Different versions or forms of a gene. Alleles can produce different variations of a particular trait, such as blue or brown eye color. Dominant: An allele that, when present, masks the expression of the recessive allele and determines the organism's phenotype (observable trait). Recessive: An allele whose expression is masked by a dominant allele. It only manifests when the dominant allele is absent. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Homozygous: When an organism has two identical alleles for a particular gene (e.g., two dominant alleles (AA) or two recessive alleles (aa)). Heterozygous: When an organism has two different alleles for a particular gene (e.g., one dominant allele and one recessive allele (Aa)). Hybrid: An organism that is heterozygous for a specific trait, resulting from the crossing of two genetically different individuals. Phenotype: The observable physical or biochemical characteristics of an organism, determined by its genetic makeup (genotype) and environmental influences. Genotype: The genetic makeup of an organism, referring to the specific combination of alleles present for a particular trait. It represents the genetic code or the alleles an organism carries for a specific trait. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Germ cells: Germ cells are specialized cells that are involved in sexual reproduction. They are the cells that give rise to gametes (sperm cells in males and egg cells in females) through the process of meiosis. Germ cells are unique because they are the only cells in the body capable of passing genetic information to the next generation. During fertilization, when a sperm cell and an egg cell unite, they form a zygote, which eventually develops into a new organism. Somatic cells: Somatic cells refer to any cell in the body that isn't a reproductive or germ cell. They make up the tissues, organs, and structures within an organism and are diploid, containing a full set of chromosomes (two sets in humans). Somatic cells undergo mitosis to replicate and divide, contributing to growth, development, and the maintenance of the body. Mitosis: Mitosis is the process of cell division that results in two daughter cells, each with an identical set of chromosomes as the parent cell. It involves several stages: prophase, metaphase, anaphase, and telophase. During mitosis, the cell's nucleus divides, ensuring that each daughter cell receives the same genetic material as the parent cell. This process is vital for growth, repair, and asexual reproduction in multicellular organisms. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Stages in mitosis Mitosis consists of several stages: 1. Prophase: - Chromatin condenses into visible chromosomes. - The nuclear envelope breaks down. - Spindle fibers form and extend from the centrosomes. 2. Metaphase: - Chromosomes line up along the cell's equator (metaphase plate). - Spindle fibers attach to the centromeres of the chromosomes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  3. Anaphase: - Sister chromatids separate and move toward opposite poles of the cell. - The spindle fibers shorten, pulling chromatids to opposite ends. 4. Telophase: - Chromatids reach the poles and begin to decondense into chromatin. - Nuclear envelopes start to form around each set of chromosomes. - The spindle fibers disassemble. 5. Cytokinesis: - This is not a stage of mitosis but occurs simultaneously or immediately after telophase. - The cell's cytoplasm divides, creating two daughter cells, each with a complete set of chromosomes identical to the parent cell. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Differences Between Mitosis and Meiosis 1. Purpose: - Mitosis: Primarily for growth, repair, and asexual reproduction, producing two identical daughter cells. - Meiosis: For sexual reproduction, generating four genetically diverse daughter cells (gametes) with half the chromosome number. 2. Number of Divisions: - Mitosis: One division, resulting in two daughter cells. - Meiosis: Two divisions, leading to four daughter cells. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 3. Chromosome Number: - Mitosis: Daughter cells have the same chromosome number as the parent cell (diploid). - Meiosis: Daughter cells have half the chromosome number of the parent cell (haploid). 4. Genetic Variation: - Mitosis: Results in identical daughter cells, maintaining genetic consistency. - Meiosis: Promotes genetic diversity due to crossing over during prophase I and random assortment of chromosomes during metaphase I. 5. Occurrence: - Mitosis: Occurs in somatic cells (body cells) for growth, repair, and maintenance. - Meiosis: Occurs in germ cells (sex cells) for the formation of gametes (sperm and egg cells) in sexual reproduction. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Meiosis: Meiosis is a type of cell division that occurs in sexually reproducing organisms. It involves two successive divisions, resulting in the production of four daughter cells, each with half the number of chromosomes as the parent cell. This reduction in chromosome number is essential for sexual reproduction, as it produces gametes (sperm and egg cells) that, upon fertilization, combine to restore the original chromosome number in the resulting zygote. Meiosis involves one round of DNA replication followed by two rounds of cell division, resulting in genetic diversity among offspring. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Stages in Meiosis Meiosis I: 1. Prophase I: - Chromosomes condense, and homologous chromosomes pair up (synapsis). - Crossing over occurs, where genetic material is exchanged between paired chromosomes. - The nuclear envelope breaks down, and spindle fibers form. 2. Metaphase I: - Homologous pairs of chromosomes align along the cell's equator (metaphase plate). - Spindle fibers attach to each homologous chromosome pair. 3. Anaphase I: - Homologous chromosomes separate and move toward opposite poles of the cell. - Sister chromatids remain attached at their centromeres. 4. Telophase I: - Chromosomes arrive at the poles and may briefly decondense. - Nuclear envelopes may form, and the cell undergoes cytokinesis, resulting in two daughter cells, each haploid but with duplicated chromosomes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Meiosis II: 5. Prophase II: - Chromosomes, already duplicated, condense again. - The nuclear envelope breaks down, and spindle fibers form. 6. Metaphase II: - Duplicated chromosomes align along the cell's equator (metaphase plate) individually. 7. Anaphase II: - Sister chromatids finally separate and move toward opposite poles of the cell. 8. Telophase II: - Chromatids reach the poles, and nuclear envelopes start to form. - Cytokinesis occurs, resulting in four haploid daughter cells, each with a unique combination of chromosomes due to crossing over and random assortment during Meiosis I. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  INTERRELATIONSHIPS OF ORGANISMS (COMPETITIONS, PARASITISM, PREDATION, SYMBIOSIS, COMMENSALISMS, MUTUALISM, SAPROPHYTISM). EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  INTERRELATIONSHIPS OF ORGANISMS The interrelationships of organisms in an ecosystem are diverse and can be categorized into different types based on the nature of the interaction. Here are some common types of interrelationships: Competition: Competition occurs when two or more organisms compete for the same limited resources, such as food, water, or shelter. Example: Plants competing for sunlight in a forest, or animals competing for the same prey. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Parasitism: Parasitism is a relationship in which one organism (the parasite) benefits at the expense of another organism (the host), often causing harm to the host. Example: A tick feeding on the blood of a host organism. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Predation: Predation involves one organism (predator) capturing and consuming another organism (prey). Example: A lion hunting and killing a gazelle for food. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  Symbiosis: Symbiosis is a long-term interaction between two different species, where at least one species benefits from the relationship. Examples: Mutualism: Both species benefit. For example, the relationship between bees and flowers, where bees obtain nectar while aiding in pollination. Commensalism: One species benefits, and the other is neither harmed nor helped. For example, birds nesting in trees. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 ELEMENTS OF ECOLOGY AND TYPES OF HABITAT EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Individual: The basic unit of ecology is the individual organism. Understanding an organism's characteristics, behavior, and adaptations is crucial for studying ecological interactions. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Population: A population comprises individuals of the same species that live in a particular area and interact with each other. Population ecology focuses on factors like population size, density, distribution, and dynamics. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Community: A community consists of different populations of species living in the same area and interacting with each other. Community ecology explores the relationships, such as competition, predation, and mutualism, between various species. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Ecosystem: An ecosystem includes both living organisms (biotic factors) and their physical environment (abiotic factors). It encompasses the flow of energy and cycling of nutrients within a defined space. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Biome: A biome is a large geographic region characterized by a specific climate, vegetation, and animal life. Examples include tropical rainforests, deserts, grasslands, and tundras. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Biosphere: The biosphere represents the sum of all ecosystems on Earth, where living organisms exist. It includes the atmosphere, lithosphere, and hydrosphere. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Habitat: A habitat is the specific environment where an organism or community of organisms lives. It provides the necessary resources for survival, such as food, water, shelter, and suitable conditions. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Niche: The ecological niche is the role or function of a species within its habitat. It encompasses how an organism obtains and uses resources and interacts with other species. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Abiotic Factors: These are non-living components of the environment, including temperature, humidity, soil composition, sunlight, and water availability. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Biotic Factors: Biotic factors are living components of an ecosystem, including plants, animals, fungi, and microorganisms. Interactions among biotic factors shape the dynamics of ecosystems. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Ecological Succession: This is the process of gradual, predictable changes in the composition and structure of an ecological community over time. It includes primary and secondary succession. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  ELEMENTS OF ECOLOGY Biogeochemical Cycles: These cycles describe the movement of essential elements like carbon, nitrogen, and phosphorus between living organisms and the abiotic components of ecosystems. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  1. TERRESTRIAL HABITATS: Forests: Tropical rainforests, temperate deciduous forests, coniferous forests. Grasslands: Savannas, prairies, steppes. Deserts: Hot deserts, cold deserts. Tundra: Arctic tundra, alpine tundra. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  2. AQUATIC HABITATS: Marine: Oceans, seas. Freshwater: Lakes, rivers, ponds. Wetlands: Swamps, marshes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  3. SPECIALIZED HABITATS: Caves: Subterranean environments. Urban Habitats: Cities and human-impacted areas. Polar Habitats: Polar regions with extreme cold conditions. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 4. MICROHABITATS: Microhabitats refer to small, specialized environments within a larger habitat that have distinct physical and ecological characteristics. These microhabitats offer unique conditions that influence the distribution and behavior of specific organisms. Here are some examples of microhabitats: Tree canopies, leaf litter, burrows, rock crevices. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  1. Tree Canopies: The upper layer of branches and leaves in a forest or woodland. Tree canopies provide a different set of environmental conditions compared to the forest floor. They receive more sunlight, experience different wind patterns, and may have higher humidity levels. Many species, such as certain birds, insects, and epiphytic plants, inhabit tree canopies. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  2. Leaf Litter: The layer of dead leaves and plant material on the forest floor. Leaf litter creates a microhabitat with high humidity, protection from predators, and a diverse array of decomposer organisms. Many small invertebrates, fungi, and microorganisms thrive in this environment. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  3. Burrows: Holes or tunnels in the ground created by animals for shelter, protection, or nesting. Burrows offer a secure and often temperature-stable environment. Many small mammals, reptiles, and invertebrates, such as rodents, reptiles, and spiders, create burrows for protection against predators and adverse weather conditions. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  4. Rock Crevices: Narrow openings or gaps in rocks, cliffs, or boulders. Rock crevices provide a sheltered space with varying microclimates. Organisms adapted to arid conditions, such as certain plant species, insects, and reptiles, may inhabit these areas. The crevices offer protection from extreme temperatures and predators. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1  HEREDITY AND EVOLUTION (INTRODUCTION TO DARWINISM AND LAMARKISM, MENDELIAN LAWS, EXPLANATION OF KEY GENETIC TERMS). EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Heredity: Heredity refers to the passing of traits or characteristics from parents to offspring through genetic information. Heredity describes the biological processes by which certain characteristics are transmitted from parents to their offspring. These traits which are passed from one generation to another are called inherited traits as they are inherited from the previous generation. Evolution refers to the changes which occur in these inheritable traits over a long period of time. Genetic information is encoded in DNA, which is located in the chromosomes. Offspring inherit a combination of genetic material from both parents. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Evolution: Evolution is the process of gradual change in all aspects of organisms over successive generations. Mechanism: Natural selection, genetic variation, and adaptation are key components of evolutionary processes. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Introduction to Darwinism Charles Darwin: Proposed the theory of natural selection in his work "On the Origin of Species" (1859). Natural Selection: Individuals with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Introduction to Lamarckism - Jean-Baptiste Lamarck: Suggested the inheritance of acquired characteristics. - Lamarckian Evolution: Organisms can change during their lifetime in response to their environment, and these acquired traits are passed on to their offspring. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Mendelian Laws of Inheritance: Gregor Mendel: Known as the father of modern genetics. - Mendelian Laws: - Law of Segregation: Each individual has two alleles for a trait, and these alleles segregate during the formation of gametes. - Law of Independent Assortment: Genes controlling different traits assort independently during gamete formation. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1 Explanation of Key Genetic Terms: - Genotype: Genetic makeup of an organism (combination of alleles). - Phenotype: Observable characteristics or traits of an organism. - Allele: Different forms of a gene. - Dominant: An allele that expresses its phenotype even in the presence of a recessive allele. - Recessive: An allele whose expression is masked by a dominant allele. - Homozygous: Having two identical alleles for a particular gene. - Heterozygous: Having two different alleles for a particular gene. EDO STATE UNIVERSITY UZAIRUE- BIO 101 – GENERAL BIOLOGY 1