BIO1101 - 2024 Lectures- General Biology PDF

29/08/1445 General Biology Lecture (1-2) The Cell College of Applied Sciences Biology Department 03/10/2024 1  29/08/1445 Outline ...

29/08/1445 General Biology Lecture (1-2) The Cell College of Applied Sciences Biology Department 03/10/2024 1  29/08/1445 Outline  Biological Organization  The cell Historical overview Cell Theory Types of Cells Eukaryotic Cell structure  Extracellular components  Cell Communication  Metabolism 2  29/08/1445 Biological Organization Living things are highly organized and structured, following a hierarchy from small to large. The biological levels of organization of living things arranged from the simplest to most complex are: atom, molecule, organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere. The atom is the smallest and most fundamental unit of matter. It consists of a nucleus surrounded by electrons. Atoms form molecules which are chemical structures consisting of at least two atoms held together by one or more chemical bonds. 3  29/08/1445 Biological Organization Many molecules that are biologically important are macromolecules (polymers). A polymer is a large molecule that is made by combining smaller units called monomers. ▪ All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids, three of which are polymers: – Carbohydrates (include sugars and the polymers of sugars). – Proteins (consists of one or more polypeptides). – Nucleic acids (made of monomers called nucleotides). 4  29/08/1445 Biological Organization Macromolecules can form aggregates within a cell that are surrounded by membranes; these are called organelles such as mitochondria and chloroplasts. All living things are made of cells, and the cell itself is the smallest fundamental unit of structure and function in living organisms. In larger organisms, cells combine to make tissues. Organs are collections of tissues grouped together performing a common function. An organ system is a higher level of organization that consists of functionally related organs. A complex organism contains multiple organ systems with different functions. 5  29/08/1445 Cell Structure & Function 6  29/08/1445 Historical overview The term cell is derived from the latin word ‘Cellula’ which mean a small room. It was first observed by a scientist named ‘Robert Hook’ in the year 1665. He examined sliver of cork and saw “row of empty boxes” and coined the term cell 7  29/08/1445 Cell Theory cell theory is a scientific theory first formulated in the mid-nineteenth century and state that: All living organisms are made up of cells. Cells are the smallest working units of all living organisms. All cells come from preexisting cells through cell division. 8  29/08/1445 Types of Cells There are two distinct types of cells: prokaryotic or eukaryotic. Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells. Protists, fungi, animals, and plants all consist of eukaryotic cells. 9  29/08/1445 Prokaryotic Cells Prokaryotic cells are characterized by having – No nucleus. – DNA in an unbound region called the nucleoid. – No membrane-bound organelles. – Cytoplasm bound by the plasma membrane. 10  29/08/1445 Eukaryotic Cells Eukaryotic cells are characterized by having – DNA in a nucleus that is bounded by a membranous nuclear envelope. – Membrane-bound organelles. – Cytoplasm in the region between the plasma membrane and nucleus. Eukaryotic cells are generally much larger than prokaryotic cells. 11  29/08/1445 Comparing Prokaryotic and Eukaryotic Cells Common features between prokaryotic and eukaryotic cells of: – Plasma membrane. – Semifluid substance called cytoplasm (cytosol). – Chromosomes (carry genes). – Ribosomes (make proteins). 12  29/08/1445 Eukaryotic VS Prokaryotic cells Prokaryotic Cells Eukaryotic Cells Nuclear region (nucleoid) is not Nucleus is surrounded by a enveloped by a nuclear double membrane layer. membrane. Single chromosome More than one chromosome present. are present. Nucleolus is absent. Nucleolus is present. Membrane bound organelles Membrane bound are absent. organelles are present. 13  29/08/1445 Eukaryotic VS Prokaryotic cells Prokaryotic Cells Eukaryotic Cells Cell division by mitosis or Multiplication of cell is by fission meiosis. or budding. Cell walls seen in only plant Cell Walls present, which are cells, which are chemically chemically complex. simpler. Cell type is usually Usually multicellular cells. unicellular. Cell size is 1-10μm Cell size 10 - 100µm. Example: Bacteria, archaea Example: animal cells and plant cells. 14  29/08/1445 Eukaryotic Cell structure the cell membrane The nucleus The cytoplasm Nucleolus Cytoplasmic inclusion Nuclear envelop Matrix Nuclear plasma organelles Cytoplasmic skeleton Chromatin materials15  29/08/1445 1. Plasma Membrane The plasma membrane is the boundary that separates the living cell from its surroundings. Also called Cell membrane Semi-permeable: allows nutrients in and waste products out Plasma membrane is made of a double layer of phospholipids. 16  29/08/1445 Cell Membrane structure The currently accepted model for the structure of the plasma membrane, called the fluid mosaic model According to this model the plasma membrane is a mosaic of components—primarily, phospholipids, cholesterol, and proteins—that move freely and fluidly in the plane of the membrane. Phospholipids are the most abundant lipid in the plasma membrane. Phospholipids are amphipathic molecules, containing hydrophobic and hydrophilic regions. 17  29/08/1445 Cell Membrane functions 1. The main function of plasma membrane is that it acts as a physical barrier between the external environment and the inner cell organelles. 2. Plays a vital role in protecting the interior of the cell by allowing only selected substances into the cell and keeping other substances out. 3. Facilitating the communication and signaling between the cells. 4. Maintaining the shape of the cell because it serves as a base of attachment for the cytoskeleton in some organisms. 18  29/08/1445 2- The Cytoplasm It is colloidal (Gel-like) mixture rich in proteins, carbohydrate, lipids, enzymes, minerals, ions and vitamins. Contains many membranous and non membranous organelles. Cell organelles are small organs each of them performed certain function which is essential for life and metabolism of cells 19  29/08/1445 Ribosomes: Protein Factories Small non-membrane bound organelles Ribosomes are particles contain two subunits made of ribosomal RNA and protein. Ribosomes carry out protein synthesis in two locations: – In the cytosol (free ribosomes) – On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) 20  29/08/1445 The Endoplasmic Reticulum: Biosynthetic Factory The endoplasmic reticulum (ER) is complex network of transport channel accounts for more than half of the total membrane in many eukaryotic cells. The ER membrane is continuous with the nuclear envelope. There are two distinct types of ER: – Smooth ER, which lacks ribosomes. – Rough ER, with ribosomes studding its surface. 21  29/08/1445 The Endoplasmic Reticulum function The Function The smooth ER The rough ER 1- Metabolizes carbohydrates secrete glycoproteins (proteins covalently bonded to carbohydrates) 2- Synthesises glycogen, lipids It participates in the synthesis of and steroids. enzymes and proteins. 3- Detoxifies poison Is a membrane factory for the cell 4- Provides vesicles for cis-face Provides proteins and lipids for Golgi of Golgi apparatus. apparatus. 22  29/08/1445 The Golgi Apparatus: Shipping and Receiving Center The Golgi apparatus consists of flattened membranous sacs called cisternae. Functions of the Golgi apparatus: – Modifies products of the ER. – Manufactures certain macromolecules. – Sorts and packages materials into transport vesicles. 23  29/08/1445 Lysosomes: Digestive Compartments A lysosome is a membranous sac of hydrolytic enzymes that can digest macromolecules. The main function is digestion. Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids. 24  29/08/1445 Vacuoles: Diverse Maintenance Compartments A plant cell or fungal cell may have one or several vacuoles. The functions of the vacuole include: - Storage, digestion, and waste removal. 25  Mitochondria and chloroplasts 29/08/1445 change energy from one form to another Mitochondria are the sites of cellular respiration, a metabolic process that generates ATP. Chloroplasts, found in plants and algae, are the sites of photosynthesis Mitochondria and chloroplasts Both have: – A double membrane. – Proteins made by free ribosomes. – Contain their own DNA. 26  29/08/1445 Mitochondria: Chemical Energy Conversion Mitochondria are in nearly all eukaryotic cells. They have a smooth outer membrane and an inner membrane folded into cristae. The inner membrane creates two compartments: intermembrane space and mitochondrial matrix. Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix. Cristae present a large surface area for enzymes that synthesize ATP. 27  29/08/1445 Chloroplasts: Capture of Light Energy ▪ The chloroplast is a member of a family of organelles called plastids. ▪ Chloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis. ▪ Chloroplasts are found in leaves and other green organs of plants and in algae. ▪ Light energy absorbed by chlorophyll results in the synthesis of organic molecules in the chloroplast. 28  29/08/1445 The cytoskeleton ▪ The cytoskeleton is a network of fibers extending throughout the cytoplasm. ▪ It organizes the cell’s structures and activities, anchoring many organelles. ▪ The roles of Cytoskeleton are Support, Motility, and Regulation. ▪It is composed of three types of molecular structures: – Microtubules are the thickest of the three components of the cytoskeleton. – Microfilaments also called actin filaments, are the thinnest components. – Intermediate filaments are fibers with diameters in a middle range. 29  29/08/1445 The cytoskeleton Microtubules control the beating of cilia and flagella, locomotor appendages of some cells. Cilia and flagella differ in their beating patterns. 30  29/08/1445 Centrosomes and Centrioles In many cells, microtubules grow out from a centrosome near the nucleus. The centrosome is a “microtubule-organizing center.” In animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring. 31  29/08/1445 3. The Nucleus: Information Central The nucleus directs cell activities. Separated from cytoplasm by the nuclear envelope. The nuclear envelope is a double membrane; each membrane consists of a lipid bilayer, and it contains pores. Pores regulate the entry and exit of molecules from the nucleus. In the nucleus, DNA and proteins form genetic material called chromatin. The nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis. 32  29/08/1445 Summary of the Cell organelle 33  29/08/1445 Summary of the Cell organelle 34  29/08/1445 Plant and Animal Cells 35  29/08/1445 Plant Cell VS Animal cell Feature Plant Cell Animal Cell Cell Wall Present in almost all cells, made of cellulose Absent Lack rigidity, round (irregular Cell shape and structure Rigid, fixes rectangular shape. shape) Plastids Present. Absent Vacuoles usually absent or one or more small Present vacuoles are seen. Lysosomes Lysosomes not evident. Present Nucleus Present usually located Present may be located at the edge of the cell. centrally. Golgi bodies Present Present Centrioles Present only in lower plant forms (e.g. Present in all animal cells chlamydomonas). Starch grains Present Absent 36  29/08/1445 Plant Cell VS Animal cell Feature Plant Cell Animal Cell Flagella Present in some cells (e.g. sperm Present in some cells (e.g. mammalian sperm of bryophytes and cells) pteridophytes, cycads and Ginkgo) Cilia Most plant cells do not contain Present cilia. Mitochondria Present Present Ribosomes Present Present Endoplasmic Reticulum (Smooth Present Present and Rough) Microtubules/ Microfilaments Present Present 37  29/08/1445 Extracellular components ▪ Most cells synthesize and secrete materials that are external to the plasma membrane. ▪ These extracellular structures include: – Cell walls of plants: It protects the plant cell, maintains its shape, and prevents excessive uptake of water. – The extracellular matrix (ECM) of animal cells: it helps in supporting, movement, and regulation of the cells 38  29/08/1445 Cell Communication Cells in a multicellular organism communicate by signaling molecules (chemical messengers) targeted for cells that immediately adjacent or far from them. In local signaling, cells communicate by direct contact (cell junctions) or cell-cell recognition. In many other cases of local signaling, signaling molecules are secreted by the signaling cell and travel only short distances; such local regulators influence cells that are nearby. 39  29/08/1445 Cell Communication In long-distance signaling (up to body-length distance), plants and animals use chemicals called hormones. In hormonal signaling in animals, specialized cells release hormones, which travel through the circulatory system to other parts of the body, and reach target cells that can recognize and respond to them 40  29/08/1445 Overview: Life Is Work Living cells require energy from outside sources. Energy flows into an ecosystem as sunlight and leaves as heat. Photosynthesis generates O2 and organic molecules, which are used in cellular respiration. Cells use chemical energy stored in organic molecules to regenerate ATP, which powers work. 41  29/08/1445 Metabolism Metabolism is the totality of an organism’s chemical reactions. A metabolic pathway begins with a specific molecule and ends with a product. Each step is catalyzed by a specific enzyme. There are two types of metabolism: Catabolism and Anabolism 42  29/08/1445 Types of Metabolism:Catabolism Catabolism pathways release energy by breaking down complex molecules into simpler compounds. Cellular respiration that occurs in the mitochondria is a catabolic process during which glucose is broken down to release usable energy (ATP) can then be used by other reactions in the cell for a cell. 43  29/08/1445 Types of Metabolism:Anabolism Anabolism pathways consume energy to build complex molecules from simpler ones. Photosynthesis that occurs in the chloroplast in plants is an anabolic process during which plants use energy from sunlight to convert carbon dioxide gas and water into sugar molecules used by the plant itself, or it can be used as a food source for other organisms.. 44  29/08/1445 Campbell Biology, 12th Edition, Author(s): Lis a A. Urry, Micheal L.Cain, Steven A. Wasserman, Peter V. Minorsky, Rebecca B. Orr, Neil A. Campbell, Publisher: Pearson, Year: 2020, ISBN: 9780135988046; 0135988047 1.8: Themes and Concepts of Biology - Levels of Organization of Living Things available at https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology _(Boundless)/01%3A_The_Study_of_Life/1.08%3A__Themes_and_Concepts_of_Biology_- _Levels_of_Organization_of_Living_Things 45  29/08/1445 General Biology Lecture (3-4): Genetics College of Applied Sciences Biology Department 03/10/2024 46  29/08/1445 Outline  Introduction into Genetics  The Molecular Basis of Inheritance  The Components of Nucleic Acids  The Structures of DNA and RNA Molecules  The Chromosomal Basis of Inheritance  Chromosome Theory  Inheritance of Genes  The Cell Cycle & Cell Division.  Type of cell division  Cell cycle stages  Mitosis  The Flow of Genetic Information  Biotechnology 47  29/08/1445 1. Introduction into Genetics College of Applied Sciences Biology Department 48  29/08/1445 Overview: Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind. Genetics is the scientific study of heredity and variation. Heredity is the transmission of traits from one generation to the next. Variation is demonstrated by the differences in appearance that offspring show from parents and siblings. 49  29/08/1445 2.The Molecular Basis of Inheritance College of Applied Sciences Biology Department 50  29/08/1445 Mendel used the scientific approach to identify two laws of inheritance The “particulate” hypothesis is the idea that parents pass on discrete heritable units (genes) Mendel documented a particulate mechanism through his experiments with garden peas. Mendel discovered the basic principles of heredity by breeding garden peas in carefully planned experiments. 51  29/08/1445 Overview: Life’s Operating Instructions In 1953, James Watson and Francis Crick shook the world With an elegant double-helical model for the structure of deoxyribonucleic acid, or DNA. Watson and Crick deduced that DNA was a double helix, through observations of the X-ray crystallographic images of DNA The role of DNA in heredity worked out by studying bacteria and the viruses that infect them. DNA, the substance of inheritance and the most celebrated molecule of our time. 52  Nucleic acids store, transmit, and express hereditary information ▪ The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene. ▪ Genes are made of DNA, a nucleic acid made of monomers called nucleotides. ▪ There are two types of nucleic acids: - Deoxyribonucleic acid (DNA) - Ribonucleic acid (RNA) ▪ DNA provides directions for its own replication. ▪ DNA directs synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis. ▪ Protein synthesis occurs on ribosomes.  The Components of Nucleic Acids ▪ Nucleic acids are polymers called polynucleotides. ▪ Each polynucleotide is made of monomers called nucleotides. ▪ Each nucleotide consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups. ▪ There are two families of nitrogenous bases – Pyrimidines (cytosine, thymine, and uracil) – Purines (adenine and guanine). ▪ In the DNA double helix, the two backbones run in opposite 5′→ 3′ directions from each other, an arrangement referred to as antiparallel. ▪ The nitrogenous bases in DNA pair up and form hydrogen bonds: adenine (A) always with thymine (T), and guanine (G) always with cytosine (C). Called complementary base pairing. The Structures of DNA and RNA Molecules  The Structures of DNA and RNA Molecules RNA is slightly different from DNA in the following aspects DNA RNA (Deoxyribonucleic acid) (Ribonucleic acid) Location Nucleus and mitochondria, Nucleus and cytoplasm, chloroplast. Structure Double strand helix. Single-strand helix. Sugar It contains Deoxyribose. It contains Ribose. Nitrogenous AT (adenine-thymine). AU (adenine-uracil). Bases GC (guanine-cytosine). GC (guanine-cytosine). Length Long with high molecular mass. Short with low molecular mass. Propagation DNA is self-replicating. RNA is synthesized from DNA. Function storage and transmission of Transfers genetic code for protein genetic information. synthesis. Type ___________ (tRNA), (rRNA), (mRNA),(snRNA)  29/08/1445 3. The Chromosomal Basis of Inheritance College of Applied Sciences Biology Department 57  29/08/1445 Chromosome Theory The chromosomal basis of Mendel’s laws The chromosome theory of inheritance states that: – Mendelian genes have specific loci on chromosomes. – Chromosomes undergo segregation and independent assortment. – Thomas Hunt Morgan. – Provided convincing evidence that chromosomes are the location of Mendel’s heritable factors. 58  29/08/1445 Inheritance of Genes ▪ In a literal sense, children do not inherit particular physical traits from their parents. ▪ It is genes that are actually inherited. ▪ Genes are the units of heredity, and are made up of segments of DNA. ▪ Genes are passed to the next generation through reproductive cells called gametes (sperm and eggs). ▪ Each gene has a specific location called a locus on a certain chromosome. ▪ One set of chromosomes is inherited from each parent. ▪ Most DNA is packaged into chromosomes. Offspring acquire genes from parents by inheriting chromosomes 59 DNA Packaging and Organization into Chromosomes  29/08/1445 4. The Cell Cycle & Cell Division. College of Applied Sciences Biology Department 61  29/08/1445 The Cell Cycle The ability of organisms to reproduce best distinguishes living things from non living matter. The continuity of life is based on the reproduction of cells, or cell division. The frequency of cell division varies with the type of cell. A life cycle is the generation-to- generation sequence of stages in the reproductive history of an organism. 62  29/08/1445 Cell division In unicellular organisms like in bacteria, division of one cell reproduces the entire organism called by Binary fission. Eukaryotic cell division consists of: 1- Mitosis, most cell division results in daughter cells with identical genetic information, DNA. Mitotic division, the division of the nucleus. Cytokinesis, the division of the cytoplasm. 2- Miosis a special type of division produces non - identical daughter cells (gametes, or sperm and egg cells). 63  29/08/1445 Comparison of Asexual and Sexual Reproduction In asexual reproduction, one parent produces genetically identical offspring by mitosis. A clone is a group of genetically identical individuals from the same parent. In sexual reproduction, two parents give rise to offspring that have unique combinations of genes inherited from the two parents. 64  29/08/1445 Phases of the Cell Cycle The cell cycle consists of : ▪ Interphase (cell growth and copying of chromosomes in preparation for cell division). ▪ Mitotic (M) phase (mitosis and cytokinesis). Interphase (about 90% of the cell cycle) can be divided into subphases: G1 phase (“first gap”) S phase (“synthesis”) G2 phase (“second gap”) The cell grows during all three phases, but chromosomes are duplicated only during the S phase. 65  Interphase Stage 29/08/1445 1st growth stage of cell division. Cell carries on its normal metabolic activities. Cells mature by making more cytoplasm & organelles, proteins and RNA. DNA Synthesis stage Occurs prior to division. DNA is copied or replicated. Because of duplication, each condensed chromosome consists of 2 identical chromatids joined by a centromere, called sister chromatids. Each duplicated chromosome contains 2 identical DNA molecules. 66  Mitosis 29/08/1445 Mitosis is divided into five phases: ▪ Prophase: The chromatin fibers become more tightly coiled, condensing into discrete chromosomes. ▪ Prometaphase: The two pairs of centrioles move to opposite poles, and mitotic spindle begins to capture and organize the chromosomes. ▪ Metaphase: the spindle has captured all the chromosomes and lined them up at the middle of the cell, ready to divide. ▪ Anaphase: the sister chromatids separate from each other and are pulled towards opposite ends of the cell. ▪ Telophase: Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements. ▪ Cytokinesis: the division of the cytoplasm to form two new cells with identical genetic materials. 67 Mitosis  29/08/1445 Meiosis and Sexual life Cycle Human somatic cells (any cell other than a gamete) have 23 pairs of chromosomes. one chromosome from each parent. Each set of 23 consists of 22 autosomes and a single sex chromosome. In an egg (ovum), the sex chromosome is XX ,while In a sperm cell, the sex chromosome may be either X or Y. The two chromosomes in each pair are called homologous chromosomes, are same in length. A diploid cell (2n) has two sets of chromosomes, For humans, the diploid number is 46 (2n = 46). A haploid cell (n) contains a single set of chromosomes, A gamete (sperm or egg) For humans, the haploid number is 23 (n = 23). 69  29/08/1445 Behavior of Chromosome Sets in the Human Life Cycle Fertilization is the union of gametes (the sperm and the egg) The fertilized egg is called a zygote and has one set of chromosomes from each parent. The zygote produces somatic cells by mitosis and develops into an adult. At sexual maturity, the ovaries and testes produce haploid gametes. Gametes are the only types of human cells produced by meiosis, rather than mitosis. Meiosis results in one set of chromosomes in each gamete. Fertilization and meiosis alternate in sexual life cycles to maintain chromosome number. 70  29/08/1445 Meiosis Reduces the number of chromosome sets ▪ Like mitosis, meiosis is preceded by the replication of chromosomes. ▪ Meiosis takes place in two sets of cell divisions, called meiosis I and meiosis II. ▪ The two cell divisions result in four daughter cells, rather than the two daughter cells in mitosis. ▪ Each daughter cell has only half of chromosomes in the parent cell. 71  29/08/1445 Meiosis Reduces the number of chromosome sets ▪ In the first cell division (meiosis I), homologous chromosomes separate. ▪ Meiosis I results in two haploid daughter cells with replicated chromosomes; it is called the reductional division. ▪ In the second cell division (meiosis II), sister chromatids separate. ▪ Meiosis II results in four haploid daughter cells with unreplicated chromosomes; it is called the equational division. 72  Meiosis I 29/08/1445 ▪ Meiosis I is preceded by interphase, in which chromosomes are replicated to form sister chromatids. ▪ The sister chromatids are genetically identical and joined at the centromere. ▪ The single centrosome replicates, forming two centrosomes. 73 Comparison Meiosis I vs Meiosis II Meiosis I Meiosis II 29/08/1445 - Results two Daughter cells. - Results Four Daughter cells. - Consist four stages Prophase I , Metaphase I, - Consist four stages Prophase II , Metaphase II, Anaphase I, Telophase I. Anaphase II, Telophase II. - Homologous chromosome are present at the - Individual, bivalent chromosome are present at beginning. the beginning. - Reduce the chromosome number in the - Equalizes the chromosome number for both daughter cell. parent and daughter cell. Cell division occurs in one parental cell divided - Cell division occurs in the two daughter cell in into two daughter cell. the same time to produce four daughter cells. Interphase - DNA replication, followed by meiosis1. - No interphase takes place prior to the meiosis II. Prophase - The chromosome condense and become more - If the chromosomes decondensed in telophase I, coiled. they condense again. - The homologous chromosome Pairing (lines up closely together) and a tetrad is formed. Each - No chromosomal cross-over occurs. tetrad is composed of four chromatids. - crossing over is occurs by exchanging the genetic material between non-sister chromatids, leading to the genetic recombination. 74  Meiosis I vs Meiosis II 29/08/1445 Comparison Meiosis I Meiosis II Metaphase - The homologous chromosomes(tetrads) move to the - The sister chromatids line up at the equator metaphase plate and arrange in an independent of the cell individually. orientation of pairs of in the cell equator. Anaphase - The centromere did not divided and The sister - The centromere divided (split) and the sister chromatids are still attached at the centromers. chromatids are separated. - The Homologous chromosomes are separated and - The sister chromatids are separated and pulled to the opposite poles. pulled to the opposite poles. Telophase - The chromosomes arrive at opposite poles - The two sister chromatids will separate, chromosomes begin decondensing, - Haploid set single sister chromatid are present in the of chromosomes; each chromosome still consists daughter cells. creating four haploid of two sister chromatids. daughter cells. - Chromosome begin less coiled and decondensing - Chromatides begin less coiled and into chromatin fibers and Nuclei form. decondensing into chromatin fibers and Nuclei form. Cytokinesis - The final stage of cell division, the cytoplasm - The final stage of cell division, the cytoplasm splits in two and the cell divides. splits in two and the cell divides. - forming two haploid daughter cells. - forming four haploid daughter cells. 75 ▪ Meiosis II is very similar to mitosis.??? Meiosis I & Meiosis II  29/08/1445 Mitosis vs Meiosis 77  29/08/1445 Mitosis vs Meiosis 78 Difference between Mitosis and Meiosis 29/08/1445 Mitosis is the type of cell division that Meiosis is a type of cell division that results in the formation of two daughter results in the formation of four daughter cells each with the same number and cells each with half the number of kind of chromosomes as the parent cell. chromosomes as the parent cell. 79  29/08/1445 5. The Flow of Genetic Information College of Applied Sciences Biology Department 80  29/08/1445 Overview: The Flow of Genetic Information The information content of DNA is in the form of specific sequences of nucleotides along the DNA strands. The DNA inherited by an organism leads to specific traits by dictating the synthesis of proteins. Cells are governed by a cellular chain of command DNA RNA protein The process by which DNA directs protein synthesis, called gene expression includes two stages, called transcription and translation. Protein are complex molecules, polypeptide are folded, and combined with other polypeptides to form a protein. 81  29/08/1445 Basic Principles of Transcription and Translation Transcription: - The first step in gene expression. It involves copying a gene's DNA sequence to make an RNA molecule. - The main enzyme involved in transcription is RNA polymerase, which uses a single-stranded DNA template to synthesize a complementary strand of RNA. - RNA polymerase builds an RNA strand in the 5' to 3' direction by adding each new nucleotide to the 3' end of the strand. 82  29/08/1445 Basic Principles of Transcription and Translation Translation: Once the DNA has been transcribed to mRNA, the codons must be translated to the amino acid sequence of the protein. Protein is constructed in the cytoplasm. Three steps of translation: ▪ Initiation: mRNA is binding with subunit of ribosome and aminoacyl-tRNA. ▪ Elongation: Ribosome moves along mRNA, making polypeptide chain and extending protein. ▪ Termination: Polypeptide chain is released from tRNA, and ribosome dissociates from mRNA. 83  29/08/1445 Transcription and Translation in Prokaryotes and Eukaryotes In eukaryotes: In prokaryotes: - Transcription and translation - RNA transcripts are modified occur together. before becoming true mRNA (b) Eukaryotic cell. The nucleus provides a separate compartment for transcription. The original RNA transcript, called pre-mRNA, is processed in various ways before leaving the nucleus as mRNA. 84  29/08/1445 6. Biotechnology College of Applied Sciences Biology Department 85  29/08/1445 The DNA Toolbox DNA Cloning and Its Applications Biotechnology is the manipulation of organisms or their genetic components to make useful products. Recombinant DNA, nucleotide sequences from two different sources, often two species, are combined in vitro into the same DNA molecule. Methods for making recombinant DNA are central to genetic engineering, the direct manipulation of genes for practical purposes. Microarray is a DNA technology to measurement of gene expression of thousands of different genes. Gene cloning involves using bacteria to make multiple copies of a particular gene to producing a protein product. 86  29/08/1445 Campbell Biology, 12th Edition, Author(s): Lisa A. Urry, Micheal L.Cain, Steven A. Wasserman, Peter V. Minorsky, Rebecca B. Orr, Neil A. Campbell, Publisher: Pearson, Year: 2020, ISBN: 9780135988046; 0135988047. 1- Cell cycle https://www.youtube.com/watch?v=QVCjdNxJreE&t=279s 2- Mitosis https://youtu.be/7NM-UWFHG18 3- Meiosis https://youtu.be/jjEcHra3484 4- Mitosis vs. Meiosis: Side by Side Comparison https://youtu.be/zrKdz93WlVk 5-Mendel's experiment (monohybrid cross) | https://youtu.be/wQltEeAPtIk Laws of Genetics - Lesson 5 | Don't Memorise https://youtu.be/mD0Onu2ArGA 6- DNA transcript and translate https://www.youtube.com/watch?v=8_f-8ISZ164&t=330s 7- LAC operon https://youtu.be/JcKxOj6YZu4 87  29/08/1445 General Biology Lecture (5): Biological Diversity College of Applied Sciences Biology Department 03/10/2024 88 Outline A Darwinian View of Life Systematics Taxonomy Phylogeny Diversity of life-forms 1. The viral empire Viruses 2. The cellular empire Domain Bacteria & Archaea: The Prokaryotes Domain Eukarya 1. Protists 2. Fungi BSc: General Biology 89 A Darwinian View of Life A new era of biology began in 1859 when Charles Darwin published The Origin of Species which focused biologists’ attention on the great diversity of organisms. Charles Darwin, in full Charles Robert Darwin. Charles Darwin an English naturalist whose discovered the theory of evolution that became the foundation of modern evolutionary studies. A Darwinian View of Life Darwin proposed the theory of evolution by natural selection Darwin defined evolution as "descent with modification,” descent (shared ancestry, resulting in shared characteristics) and modification (the accumulation of differences). Meaning that the species change over time, give rise to new species, and share a common ancestor. Natural selection state that heritable traits that help organisms survive and reproduce become more common in a population over time. Also, Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called artificial selection. The main ideas of natural selection: Natural selection is a process in which individuals that have certain heritable traits survive and reproduce at a higher rate than do other individuals because of those traits. Over time, natural selection can increase the frequency of adaptations that are favorable in a given environment. If an environment changes, or if individuals move to a new environment, natural selection may result in adaptation to these new conditions, sometimes giving rise to new species. Systematics What is Systematics? The discipline of systematics is the science of naming, classifies organisms and determines their evolutionary relationships. Systematists use fossil, molecular, and genetic data to infer evolutionary relationships. Two Kinds of Systematics Systematics can be divided into two closely related and overlapping levels of classification: Taxonomy and Phylogeny 1. Taxonomy is to describe, name and classifying groups or 'taxa' usually at the species level using a hierarchical system living things grouped together based on shared traits - usually what they look like or what their bodies do: For example, animals that lay eggs and have scales we call reptiles, and animals that have live births and have fur or hair we call mammals 2. Phylogeny is the evolutionary history of a species or group of related species By looking at each organism's genes, we know that gorillas (taxonomic term), say, are more closely related to humans than they are to cockroaches  Carl Linnæus- Father of Taxonomy Carl Linnæus (1707-1778) was a Swedish botanist, zoologist, and physician regarded in modern science as the 'father of taxonomy’ He was the first to consistently use a system of classification (taxonomy) to categorize organisms based on shared features He was the first to create a simple naming system, called binomial nomenclature (or two names). Example: Homo sepian or Homo sepian Role of Binomial nomenclature 1. Latin language 2. Genus start with a capital letter. 3. Species starts with small letter. 4. They are underlined or italic if typed. 5. The first word identifies the Genus and the second one is the species. Example of Binomial nomenclature: Amoeba classified as: Amoeba proteus or Amoeba proteus Linnaean System/ Hierarchical Linnaeus introduced a system for grouping species in increasingly broad categories At each level, or “rank,” species are placed in groups within more inclusive groups The taxonomic groups from broad to narrow are Classification domain, kingdom, phylum, class, order, family, genus, and species A taxonomic unit at any level of hierarchy is called a taxon  What is Phylogeny? Phylogeny is the study of relationships among different groups of organisms and their evolutionary development. The main assumptions of phylogenetic systematics are: 1. All organisms descend from a common ancestor 2. New organisms develop when existing populations split (diverge) into two groups 3. Over time, lineages experience changes in characteristics A phylogeny is represented in a diagram known as a phylogenetic tree  Phylogenetic Tree Terms Branch point (node in Greek): These are points where branching occurs. Each branch point represents the divergence of two species Monophyletic Group (Clade or PhyloCode): This group is a single branch on a phylogenetic tree that represents a group of organisms that are descended from a most recent common ancestor and all its descendants Taxon (pl.Taxa): Taxa are specific groupings or categories of living organisms. The tips of branches in a phylogenetic tree end in a taxon Sister taxa are groups that share an immediate common ancestor  Phylogenetic Tree Interpration: Example Order Family Genus Species Taxa that share a more recent common ancestor are Panthera more closely related than taxa with a less recent Felidae Panthera common ancestor pardus For example: Coyotes are more closely related Taxidea Carnivora Taxidea to Gray Wolves than to European Otters. This is Mustelidae taxus because Coyotes and Gray Wolves share a more recent common ancestor. Additionally, it can be Lutra Lutra lutra determined that Coyotes and Gray Wolves are Otter more closely related because they belong to a monophyletic group that does not include Canis Coyote latrans European Otters Canidae Canis Canis Gray Wolf lupus Diversity of life-forms Comparative genomics, which involves analysis of the nucleotide sequences of genomes, shows that the known life-forms comprise two major divisions: 1. The viral empire 2. The cellular empire Organisms in cellular empire can be classified into one of three domains: (Bacteria, Archaea, and Eukarya) based on differences in: The sequences of nucleotides in the cell's ribosomal RNAs (rRNA). The cell's membrane lipid structure. Its sensitivity to antibiotics.  Reading only The Three Domains of Life Viruses The Discovery of Viruses Fig. 19-2 RESULTS Tobacco mosaic disease stunts growth of tobacco plants and gives their leaves a mosaic coloration In the late 1800s, researchers hypothesized that a particle smaller than bacteria caused 1 Extracted sap 2 Passed sap 3 Rubbed filtered from tobacco through a sap on healthy the disease plant with porcelain tobacco plants tobacco filter known mosaic to trap disease bacteria In 1935, Wendell Stanley confirmed this hypothesis by crystallizing the infectious particle, now known as tobacco mosaic virus (TMV) 4 Healthy plants became infected General Features Definition: Virus is an ultra microscopic, infectious agent that are metabolically inert, and which multiply only within the living cells or host A virus is a tiny, infectious particle that can reproduce only by infecting a host cell Each virus has a host range, a limited number of host cells that it can infect Viruses "commandeer" the host cell and use its resources to make more viruses, basically reprogramming it to become a virus factory Because they can't reproduce by themselves (without a host), viruses are not considered living Viruses do not have cells: 1. they're very small, much smaller than the cells of living things, and are basically just packages of nucleic acid and protein 2. They lack a cellular structure, they have no cell nucleus, organelles, or cytoplasm Structure of Viruses There are a lot of different viruses in the world. However, They all have a few key features in common. These include: 1. Viral genome (nucleic acid): Made of DNA or RNA (never both) 2. Capsid: A protective protein shell encloses the viral genome. Capsids are built from protein subunits called capsomeres 3. Envelope: Some viruses have membranous envelope that surround their capsids. This envelope help viruses infect hosts A layer of membrane called the envelope (some but not all viruses) All viruses Some viruses  Shapes of Viruses Viruses display a wide diversity of shapes depends on the viral capsid structure. Capsids come in many forms, but they often take one of the following shapes: Fig. 19-3b Fig. 19-3d DNA Head Capsomere DNA Tail sheath Tail fiber Glycoprotein 70–90 nm (diameter) 80 ´ 225 nm Filamentous (Helical) Icosahedral (Spherical) Head-tail (Complex) Ex: Tobacco Mosaic Virus Ex: Adenovirus Ex: Bacteriophage T4 Importance in Nature & in Human Life 1. Cause diseases for animals and humans (Bird flu, Influenza , Polio, Corona virus) 2. Cause losses in agricultural crops (Streak , Distortion, Ring spots, Leaf roll of potato, Tobacco mosaic virus (TMV)) 3. Production of vaccines and interferon 4. Biological control for pathogenic bacteria and insect pests. Domain Bacteria & Archaea: The Prokaryotes  Overview Prokaryotes thrive almost everywhere, including places too acidic, salty, cold, or hot for most other organisms There are more prokaryotes in a handful of fertile soil than the number of people who have ever lived They have an astonishing genetic diversity Most prokaryotes are unicellular Prokaryotic cells three most common shapes are spheres (cocci), rods (bacilli), and spirals Prokaryotes are divided into two domains: bacteria and archaea  Some distinguishable Prokaryote Structures Cell wall ○ An important feature of nearly all prokaryotic cells is their cell wall, which maintains cell shape, provides physical protection, and prevents the cell from bursting in a hypotonic environment ○ Eukaryote cell walls are made of cellulose or chitin, while bacterial cell walls contain peptidoglycan Capsule ○ A polysaccharide or protein layer called a capsule covers many prokaryotes ○ Capsules may help the bacterium avoid desiccation (dehydration) by preventing water loss. Capsules can protect a bacterial cell from ingestion and destruction by white blood cells (phagocytosis) Some distinguishable Prokaryote Structures Pili/fimbriae ○ Some prokaryotes have fimbriae (also called attachment pili), which allow them to stick to their substrate or other individuals in a colony ○ Sex pili are longer than fimbriae and allow prokaryotes to exchange DNA by conjugation Fimbriae Flagella 200 nm ○ Most motile bacteria propel themselves by flagella that are structurally and functionally different from eukaryotic flagella Sex pilus 1 µm Some distinguishable Prokaryote Structures Endospores ○ Many prokaryotes form metabolically inactive endospores, which Endospore can remain dormant and viable in harsh conditions for centuries Genome o The prokaryotic genome has less DNA than the eukaryotic 0.3 µm genome o Most of the genome consists of a circular chromosome o Some species of bacteria also have smaller rings of DNA called plasmids o The typical prokaryotic genome is a ring of DNA that is not surrounded by a membrane and that is located in a nucleoid region  Nutrition in Prokaryotes Diverse nutritional and metabolic adaptations have evolved in prokaryotes: Phototrophs obtain energy from light Chemotrophs obtain energy from chemicals Autotrophs require CO2 as a carbon source Heterotrophs require an organic nutrient to make organic compounds Domain: Archaea & Bacteria Archaea Are prokaryotes and share certain traits with bacteria and other traits with eukaryotes Some archaea live in extreme environments and are called extremophiles Examples: 1. Extreme halophiles live in highly salty environments 2. Extreme thermophiles thrive in very hot environments Bacteria Archaea appear to be more closely related to Eukarya than to Bacteria Bacteria include the vast majority of prokaryotes of which most people are aware Diverse nutritional types are scattered among the major groups of bacteria Examples: 1. Rhizobium are nitrogen fixing bacteria that form root nodules in legumes and fix atmospheric N2 2. Escherichia coli resides in the intestines of many mammals and is not normally pathogenic  Eukarya Domain Eukaryotes Korarcheotes Domain Archaea Euryarchaeotes Crenarchaeotes UNIVERSAL Nanoarchaeotes ANCESTOR Proteobacteria Domain Bacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria  CHLAMYDIAS SPIROCHETES 2.5 µm 5 µm Some Major Groups of Chlamydia (arrows) inside an Leptospira, a spirochete Bacteria animal cell (colorized TEM) (colorized TEM) CYANOBACTERIA GRAM-POSITIVE BACTERIA 50 µm 1 µm 5 µm Two species of Oscillatoria, Streptomyces, the source of Hundreds of mycoplasmas filamentous cyanobacteria (LM) many antibiotics (colorized SEM) covering a human fibroblast cell (colorized SEM) Domain Eukarya: The Protists  Protists The term "protist" is a general description for eukaryotic organisms that are not animal, plant, or fungus. The smallest and simplest organisms in the eukaryotic domain. Very diverse, most protists are microscopic and unicellular (such as amoeba), but there are some true multicellular forms (such as in the brown algae, Phaeophyta). Phylogeny of eukaryotic organisms was published in a paper by Sandra L. Baldauf (2008). Three black arrows have been added to the original figure (plants, fungi, and animals). All other lineages often referred to as "protists".  Protists were classified based on similarities to a plant, animal, or fungus: (Slime moldes) Protists, the most nutritionally diverse of all eukaryotes, include: Photoautotrophs - contain chloroplasts. Heterotrophs - absorb organic molecules or ingest larger food particles. Mixotrophs - combine photosynthesis and heterotrophic nutrition. Domain Eukarya: The Fungi  Fungi Fungi are diverse and widespread. They are essential for the well-being of most terrestrial ecosystems because they break down organic material and recycle vital nutrients. Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds.  Fungi are heterotrophs and absorb nutrients from outside of their body. Fungi exhibit diverse lifestyles: (Decomposers / saphrophytes; Parasites + -; Mutualists + +). The most common body structures are multicellular filaments and single cells (yeasts). Penicillium: a mold that decomposes food. The yeast Saccharomyces cerevisiae  Fungal Morphology : hyphae The morphology of multicellular fungi enhances their ability to absorb nutrients. Fungi consist of mycelia, networks of branched hyphae adapted for absorption. Most fungi have cell walls made of chitin.  Fungi multiply either asexually, sexually, or both. The majority of fungi produce spores, which are defined as haploid cells that can undergo mitosis to form multicellular, haploid individuals. Fungus Diversity  29/08/1445 Book: Introductory Biology (CK-12). (2022, March 5). https://bio.libretexts.org/@go/page/6247 Anon, 2022. Characteristics of Protists. Available at: https://bio.libretexts.org/@go/page/1940 [Accessed December 12, 2022]. Anon, 2021. Protist Kingdom. Available at: https://bio.libretexts.org/@go/page/6617 [Accessed December 12, 2022]. Koonin, E. V. (2010) The Two Empires and Three Domains of Life in the Postgenomic Age. Nature Education 3(9):27 129  29/08/1445 General Biology Lecture (6): Plant Form and Function College of Applied Sciences Biology Department 13 03/10/2024 0 Outline  Plant Characteristics  Highlights of Plant Evolution  Plant diversity  Seed Plant structure [seed, root, stem, leaf, flower, fruit)  Plant Nutrition and Soil Structure [macronutrients micronutrients, soil, fertilizers]  Plant Responses to Internal and External Signals BSc: General Biology 131  Plant Characteristics Autotrophic (produce their own food by photosynthesis) Non-motile Multicellular Eukaryotic organisms Cell walls are composed of cellulose. Can reproduce sexually and asexually. An alternation of generations occurs (Gametophyte --> Sporophyte --> Gametophyte  Alternation of Generations The life cycle of any land plant has two distinct phases (Gametophyte and Sporophyte). The amount of time spent in each phase varies depending on the plant group. The first phase is called the gametophyte generation (phyte=plant, gameto=gamete). Gametophyte is a plant (multicellular, not just a single cell) that has a single set of chromosomes (haploid), which produces gametes via mitosis (egg and sperm cells), which are also haploid.  Alternation of Generations The second phase is called the sporophyte generation (phyte=plant, sporo=spore). Sporophytea is a plant (multicellular, not just a single cell) that has two sets of chromosomes (diploid), which is the result of the fusion of two gametes (sperm and egg), which produces haploid spores via meiosis.  Highlights of Plant Evolution 1 Origin of land plants (about 475 mya) 2 Origin of vascular plants (about 420 mya) 3 Origin of extant seed plants (about 305 mya) (bryophytes) plants Nonvascular Liverworts Land plants ‫حزازيات كبديه‬ ANCES- 1 Hornworts TRAL ‫حزازيات قرنيه‬ GREEN ALGA Mosses ‫حزازيات قائمه‬ Vascular plants Lycophytes (club mosses, plants vascular Seedless spike mosses, quillworts) ‫حزازيات سنبليه‬ 2 Pterophytes (ferns, horsetails, whisk ferns) ‫سرخسيات‬ Seed plants Gymnosperms 3 Angiosperms 500 450 400 350 300 50 0 Millions of years ago (mya)  Plant diversity Land plants can be informally grouped based on the presence or absence of vascular tissue. Bryophytes Feature Vascular Plants Non-vascular Plants Vascular systemThey have a well-developed They lack a specialised vascular vascular system system Differentiation They possess true roots, stem They lack true roots, stems and of body and leaves leaves Ploidy of main The main plant body is the The main plant body is the haploid body diploid sporophyte gametophyte Pteridophytes Vascular tissues They contain complex vascular They lack xylem and phloem tissues, i.E. Xylem and phloem Size They may grow very tall They are small in size Fertilisation They may or may not require They require water for fertilisation water for fertilisation Examples Pteridophytes, gymnosperms Bryophytes and angiosperms Dr. Maha AL-Jabri 16  Seed plants College of Applied Sciences Biology Department BSc: General Biology 137  06/10/2022 Seeds and Mature seed structure Seed is a small embryonic plant in the dormancy state, that produce of sexual reproduction in flowering plants. Mature seed structure: 1. Seed coat (Testa) 2. Embryo 3. Cotyledons BSc: General Biology 138  06/10/2022 The Plant Structure Three basic organs evolved: roots, stems, and leaves. They are organized into a root system and a shoot system: Roots rely on sugar produced by photosynthesis in the Shoot system. Shoots rely on water and minerals absorbed by the Root system. BSc: General Biology 139  Reproductive shoot (flower) Apical bud Node Internode Apical bud Shoot Vegetative system shoot Flowering Blade Leaf Plant Petiole Morphology Axillary bud Stem Taproot Lateral branch Root roots system BSc: General Biology 140  06/10/2022 The Root Root: an underground portion of Plant. Types of Root: one main vertical root (Tap root) consists of lateral roots and root hairs. Adventitious roots arise from stems or leaves BSc: General Biology 141  06/10/2022 Zones of the Root - External Anatomy 1. Meristematic zone Root cap Region of cell division 2. Elongation zone 3. Maturation (or differentiation) zone BSc: General Biology 142 142  06/10/2022 Functions of the root system 1. Responsible for anchoring and support the plant in the soil. 2. Roots absorb water and dissolved nutrients or solutes (nitrogen, phosphorous, magnesium, boron, etc.) needed for normal growth, development, photosynthesis, and reproduction. 3. In some plants, roots have become adapted for specialized functions ex: storage.. BSc: General Biology 143  Prop roots “Strangling” aerial roots Many plants have Storage roots modified roots Buttress roots Pneumatophores BSc: General Biology 144  06/10/2022 The Stem Stem: aboveground portion of shoot, bearing leaves. Divided into: Nodes (where leaves attach) Internodes (where no leaves attached) BSc: General Biology 145  06/10/2022 Functions of the Stem 1. Support of leaves, flowers, fruits 2. Conduction of water, minerals, sugars, etc. 3. Photosynthesis 4. Storage 5. Defence BSc: General Biology 146  Rhizomes Bulbs Storage leaves Stem Many Plants have Stolons Modified Stems Stolon Tubers 147  06/10/2022 The leaf and Leaf Functions The leaf is the most important vegetative organ of the plant. It is generally green flat body, have phototropism. Leaf Functions: Photosynthesis Gaseous Exchange Transpiration, Absorption and Reproduction…etc BSc: General Biology 148  (a) Simple leaf Petiole Axillary bud Leaflet Simple (b) Compound vs. leaf Compound Leaves Petiole Axillary bud (c) Doubly compound Leaflet leaf Petiole Axillary bud BSc: General Biology 149  Tendrils cling Some plant species Spines “prickly” Photosynthesis is carried out mainly by the fleshy stems have evolved Storage Leaves succulent modified leaves that plant leaves store water serve various functions Reproductive leaves Little plantlets fall off and take root in the soil Bracts Look like petals Attract pollinators BSc: General Biology 150  06/10/2022 Flower Structure and Function Flowers are the reproductive shoots of the angiosperm sporophyte. Flowers consist of four floral organs: sepals, petals, stamens, and carpels. A stamen consists of a filament topped by an anther with pollen sacs that produce pollen. A carpel / pistil has a long style with a stigma on which pollen may land. At the base of the style is an ovary containing one or more ovules. BSc: General Biology 151 Flower Structure Anther Stigma Carpel Stamen Style Filament Ovary Sepal Petal Receptacle BSc: General Biology 152  06/10/2022 Fruit Structure and Function A fruit develops from the ovary. Petal Stigma Style It protects the enclosed seeds and aids in Stamen Sepal seed dispersal by wind or animals. Ovule Ovary (in receptacle) Apple flower A fruit may be classified as: Remains of stamens and styles Sepals dry, if the ovary dries out at maturity fleshy, if the ovary becomes thick, soft, Seed Receptacle and sweet at maturity. Apple fruit (d) Accessory fruit BSc: General Biology 153  Plant Nutrition and Soil structure College of Applied Sciences Biology Department BSc: General Biology 154  06/10/2022 Plant Nutrition Plants derive most of their organic mass from the CO2 of air, but they also depend on soil nutrients such as water and minerals. The inorganic substances in plants contain more than 50 chemical elements. In studying the chemical composition of plants, we must distinguish elements that are essential from those that are merely present in the plant. A Chemical element is considered an essential element if it is required for a plant to complete its life cycle. BSc: General Biology 155  06/10/2022 Plants require elements to complete their life cycle Nine of the Essential elements are called Macronutrients because plants require them in relatively large amounts. The Macronutrients are carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium. The most common mineral BSc: General Biology deficiencies, as seen in maize 156 leaves  06/10/2022 Plants require elements to complete their life cycle Eight of the essential elements are called Micronutrients because plants need them in very small amounts. These are chlorine, iron, manganese, boron, zinc, copper, nickel, and molybdenum. BSc: General Biology 157  06/10/2022 Soil and Soil Structure Healthy soils improve plant growth by enhancing plant nutrition. Topsoil consists of mineral particles, living Topsoil organisms, and humus = the decaying organic material. Soil particles are classified by size; from largest to smallest, they are called sand, silt, and clay. Soil particle size affects the availability of Soil horizons158 water, oxygen, and minerals in the soil. BSc: General Biology  06/10/2022 Fertilization Fertilization replaces mineral nutrients that have been lost from the soil. Commercial fertilizers are enriched in nitrogen, phosphorus, and potassium. Organic fertilizers are composed of manure, fishmeal, or compost. Organic fertilizers Commercial fertilizers BSc: General Biology  Plant Responses to Internal and External Signals College of Applied Sciences Biology Department BSc: General Biology 160  06/10/2022 Plant hormones help coordinate growth, development, and responses to stimuli Hormones are chemical signals that coordinate different parts of an organism. Any response resulting in curvature of organs toward or away from a stimulus is called a tropism = a growth response. Tropisms are often caused by hormones. BSc: General Biology 161  06/10/2022 Plant Hormones In general, hormones control plant growth and development by affecting the division, elongation, and differentiation of cells. Plant hormones are produced in very low concentration, but a minute amount can greatly affect growth and development of a plant organ. BSc: General Biology 162 Reading only 06/10/2022  29/08/1445 Book: Introductory Biology (CK-12). (2022, March https://bio.libretexts.org/@go/page/6247 Anon, 2022. Characteristics of Protists. Available at: https://bio.libretexts.org/@go/page/1940 [Accessed December 12, 2022]. Anon, 2021. Protist Kingdom. Available at: https://bio.libretexts.org/@go/page/6617 [Accessed December 12, 2022]. 164  29/08/1445 General Biology Lecture (7): Animal form and function College of Applied Sciences Biology Department 16 03/10/2024 5 Outline  Animal Development  Basic Principles of Animal Form and Function  Animal Nutrition  Circulation and Gas Exchange  The Immune System  Animal Reproduction  Animal Behavior BSc: General Biology 166  Animal Development College of Applied Sciences BSc: General Biology Biology Department 167  Animal Development Development requires both cell growth and cell differentiation (different cells express different genes). Some animals develop directly through transient stages into adults, but others have distinct larval stages. Larva is a sexually immature stage that is morphological distinct from the adult Larvae undergo metamorphosis, transforming the animal into an adult STAGES OF MAMMALIAN DEVELOPMENT Fertilization = union of gametes (sperm & egg) 3 steps involved in fertilization Penetration: head of sperm (acrosome) release enzymes to digest glycoprotein layer (zona pellucida) surrounding egg Activation: sperm physically contacts egg plasma membrane Zygote formations Cleavage is a sequence of cell divisions The ectoderm forms the outer layer The endoderm lines the digestive tract The mesoderm partly fills the space between the endoderm and ectoderm.  SUMMARY OF STAGES OF EMBERYONIC DEVELOPMENT Development occur during fertilization and the three stages that build the animal’s body Cleavage: cell division creates a hollow ball of cells called a blastula Gastrulation: cells are rearranged into a three-layered gastrula The ectoderm forms the outer layer The endoderm lines the digestive tract The mesoderm partly fills the space between the endoderm and ectoderm. Organogenesis: the three germ layers interact and move to give rise to organs.  Basic Principles of Animal Form and Function College of Applied Sciences BSc: General Biology Biology Department 172  Animal Form and Function In general, all the tissues are originated from the three germ layers in the embryonic stage, namely Ectoderm - It is the outermost germ layer Endoderm - It is found in between the ectoderm and endoderm. Endoderm - It is the innermost layer Germ layers  Animal Tissue Animal cells are organized into systems that are specialized for functions. Based on the functions; animal tissues are classified into four basic types are as follows: ✓ Epithelial tissue ✓ Connective tissue ✓ Muscular tissue ✓ Nervous tissue  Epithelial Tissue 1.The covering epithelial tissue. Classification of covering Epithelial tissues ✓ Based on the epithelial layers 1. Simple - Single layer 2. Stratified - More than one layer 3. Ciliated - Cells with cilia ✓ Based on the cell shapes 1. Squamous - Flat 2. Cuboidal - Cube 3. Columnar – Rectangular 2.Glandular epithelial tissue : A portion of epithelial cells folds inward, which results in the formation of a multicellular gland. Location: It is found in the stomach, intestine and pancreas. Function: It involves the synthesis and secretion of chemical substances at the epithelial surface.  Connective tissue Origin: Connective tissue arises from the mesoderm of the embryo. Location: These tissues are specialized to connect various body organs. It provides the structural framework and support different tissue to form organs. There are three main components of the connective tissue, namely, Matrix: can bejelly-likefluid, dense or rigid Cells Fibers : A. White fibres (Collagen) B. Yellow fibres (elastin) C. Reticulate fibres are thin, made up of highly branched collagenous fibres that provide support Connective tissues are further classified into the following categories: Loose connective tissue (Areolar and Adipose tissue) Fluid connective tissue (Blood and Lymph) Supportive connective tissue (Bone and Cartilage) Dense Connective tissue (Ligaments and Tendons)  Fluid connective tissue (Blood and Lymph) Blood has mainly two components, 1.Blood plasma 2.Blood corpuscles( Red +White cells)  Muscles Based on the structure, location and function, the muscular tissues are further divided into three types: 1.Skeletal muscles (or) Striated muscle 2.Smooth muscle (or) Non-striated muscle 3.Cardiac muscle The Neuroglia are a group of supportive cells for the neurons. They maintain the myelin sheath Provide nutrient support. They also retain homeostasis. Neurons communicate with each other by imparting neurotransmitters via contact points, the so-called neuronal synapses.  Coordination and Control Control and coordination within a body depend on the endocrine system and the nervous system. The endocrine system transmits chemical signals called hormones to receptive cells throughout the body via blood. A hormone may affect one or more regions throughout the body. Hormones are relatively slow acting, but can have long-lasting effects.  Animal Nutrition College of Applied Sciences BSc: General Biology Biology Department 185  Animal Nutrition It is the process through which the animal feeds by ingesting complex organic food (either in the solid or liquid form), which is then digested and absorbed into their bodies.. Classifying Different Modes of Nutrition Autotrophic Heterotrophic Organisms that Animals can produce cannot prepare their own food, their own food. using materials They must rely from inorganic on other sources animals for nutrition. Animals fall into three categories: Herbivores eat mainly autotrophs (plants and algae). Carnivores eat other animals. Omnivores regularly consume animals as well as plants or algal matter The mode of ingestion in different organisms: Animal Mode of ingestion Amoeba Engulfs food with the help of pseudopodia (false feet) and food vacuole digest it Lice‫قمل‬ Feeds by sucking blood from the skin Honeybees and Collects nectar from flowers in plants Hummingbirds Dog Chew and swallow their food using mouth Frog Long forked tongue to catch insects Infants ‫رضع‬of Feeds on mother's milk by using mouth mammalian sponge Filter tiny food particles  Digestion is converting complex or large or complex food substances (polymers) into smaller parts (monomer) that the body can absorb and stores in the tissues. During digestion, 1. Mechanical digestions(Chew and swallow their food using mouth 2. Chemical digestion (the process of enzymatic hydrolysis splits bonds in molecules with the addition of water). The complex carbohydrate present in food is broken down into glucose Fats are broken into fatty acids and glycerol Proteins are broken down into amino acids. 3.Absorption is uptake of nutrients by body cells. 4.Elimination is the passage of undigested material out of the digestive compartment. ✓ There are six classes of essential nutrients: ‫األلياف الغذائية‬  An animal’s diet must supply chemical energy, organic molecules, and essential nutrients An animal’s diet provides chemical energy, which is converted into ATP and