Biology Lectures, OCR PDF

Biology BIOLOGY AND YOU What is Biology? - comes from the Greek word “ bios” meaning life and “logos” meaning to study - the scientific study of life - the study of living things What is Life? Life...

Biology BIOLOGY AND YOU What is Biology? - comes from the Greek word “ bios” meaning life and “logos” meaning to study - the scientific study of life - the study of living things What is Life? Life - is a chemical phenomenon - sum total of chemical phenomenon exhibited by living organisms Characteristics of Living Organism 1. Metabolism - a variety of cellular reactions carried out by living organism. - mechanisms by which an organism can control its cellular activity. A. Catabolic reaction - storage products are hydrolyzed and broken into metabolically active small molecules. B. Anabolic reaction - biosynthesis of new cellular material.. -- reactions are catalyzed by specific proteins “enzymes” -- Characteristics of Living Organisms 2. Growth - develop new parts between or within older ones (intussuception). 3. Irritability - ability to react to changes in the environment. 4. Reproduction - produce itself in kind. 5. Form and Size - develop and maintain a specific complex organization of individuals. 6. Chemical composition - Composed of elements Virus - intermediate between living and nonliving. Scope and Limitations of Biology Three Major Branches of Biology: 1. Botany the scientific study of plants is the branch of biology which deals with the : Structure physiology Reproduction Evolution Diseases economic uses, and other features of plants.  2. Zoology Scope and Limitations of Biology 2. Zoology the scientific study of animals 3. Microbiology the study of microorganisms  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 1. Biosystematics - the modern term for taxonomy. - deals with the identification, naming, and classification of organisms.. Entomology the study of insects  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: Ornithology – the study of birds Herpetology – the study of reptiles and amphibians  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: Cnidarology – the study of corals Ichthyology – the study of fishes  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: Bryology – the study mosses and liverworts Pteridology – study of ferns  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: Mycology – the study of fungi Phycology – the study of algae Bacteriology – the study of bacteria  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 2. Biogeography – the study of the geographic distribution of organisms. 2 divisions: 1. Phytogeography – plants geography 2. Zoogeography – animal geography  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 3. Molecular biology or biochemistry – the study of the chemistry of living things. It includes gene biology and aspects of organic chemistry. 4. Cell biology or cytology - the study of cells  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 5. Histology – the study of tissues. 6. Organismic biology – the study of organ systems.  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 7. Ecology – the study of the relationship of organisms and their environment. - may include community biology. 8. Morphoanatomy – the study of the structure (gross) of living organisms.  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 9. Physiology – the study of biological functions 10. Genetics – the study of heredity and variation 11. Reproductive biology – the study of the various aspects of reproduction  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 12. Developmental biology – the study of the development of organisms from gamete formation to birth, (embryology) and other developmental processes.  2. Zoology Scope and Limitations of Biology Subdivisions of Biology: 13. Paleontology – the study fossil records  2. Zoology Scope and Limitations of Biology Other Branches: Pathology – the study of disease Parasitology – the study of parasite Ethology – the study of the behavior of organisms. Scientific Method -- scientific investigations follow a series of logical, orderly steps to formulate and test hypothesis-- make observation formulate hypothesis design a controlled experiment consult prior knowledge collect data interpret data draw conclusion Some Theories on the Origin of Life 1. Theory of divine creation Some Theories on the Origin of Life 2. Interplanetary Theory 3. Spontaneous generation abiogenesis life came from non-life. Some Theories on the Origin of Life Biogenesis “omni vivo ex vivo” (life came from living cell)from life). UNDERSTANDING CELLS: BUILDING PIECES OF LIFE Chemical Basis of Life Biochemistry – tries to understand LIFE. Chemical Basis of Life Chemical Basis of Life 6 Elements Present in Living Matter: Carbon Hydrogen Oxygen Nitrogen Phosphorous Sulfur Trace minerals Consistently Present in Living Things: Magnesium Iodine Iron Calcium Sodium Chlorine Potassium Chemical Basis of Life Isotopes - atoms that have the same no. of protons but different number of neutrons. Chemical Bonds – forces of attraction that hold atoms of a molecule together. 2 principal types of chemical bonds: Covalent Bond Ionic Bond Chemical Basis of Life Chemical Components of living matter: 1. Inorganic compounds - substances taken into from the outside environment. a. Water b. Gases c. Inorganic salts 2. Organic compounds - carbon-containing compounds synthesized by the living cell from inorganic raw materials. Functional group ( -R) – participate in the chemical reaction. Chemical Basis of Life Processes that subdivide organic compounds: 1. Hydrolysis - by the addition of water molecule, compound AB splits into two parts. A-B + H2O A-H + B-OH 2. Dehydration - 2 substances are combined to form a more complex molecule with a loss of water. Chemical Basis of Life Inorganic : Water = 5-95% of different animal parts contain water = 65-75% average - best solvent - favors the dissociation of electrolyte dissolved in it - has high surface tension - has a large capacity to absorb heat Gases: Oxygen present in the respiratory organs of air breathers Carbon dioxide and dissolved in tissue fluids or blood. Inorganic salts = conspicuous in skeletons or shell, often as CaCO3, Ca3(PO4)2 or SiO2. Chemical Basis of Life Organic compounds - carbon-containing compounds synthesized by the living cell from inorganic raw materials. Carbon - contain electrons by sharing them with other atoms. 1. straight-chain hydrocarbons methane (CH4) ethane (C2H6) H H H H C H H C C H H H H Chemical Basis of Life 2. Ring or aromatic compounds H H benzene (C6H6) C C H C C H C C H H Chemical Basis of Life Types or organic compounds: 1. Carbohydrates 2. Proteins 3. lipids Carbohydrates - simplest and most abundant organic compound in nature. - ultimate source of food for animals and are much used by humans (food, fabrics, wood, paper). - ¾ of solids in plants. - can be converted into fats 1. Sugars 2. Starch 3. Cellulose Chemical Basis of Life 1. sugar a. Monosaccharides - simple sugars and can’t be divided by hydrolysis 1. glucose (C6H12O6) – end product in the digestion of carbohydrates 2. ribose (C5H10O5) - present in nucleic acids 3. fructose 4. galactose b. Disaccharides - double sugars - 2 mono joined by dehydration 1. C6H12O6 + C6H12O6  C12H22O11 sucrose (table sugar) 2. lactose = glucose + galactose 3. maltose = 2 glucose units c. Polysaccharides Chemical Basis of Life Glucose - the most common monosaccharide Glucose also contains five hydroxyl groups, which officially makes it an alcohol. Chemical Basis of Life Polysaccharides - large molecules composed of many simple sugar units joined together by dehydration. Ex. Glycogen (C6H10O5)n = glucose polymer = stored in vertebrate liver Starch stored plant reserve that accumulate into starch grains Cellulose glucose polymer which is fibrous support material in plants. Chemical Basis of Life Lipids - fats, oil, waxes, steroids and related substances with less oxygen than CH2O. - do not bear the monomer-polymer relationship. - composed of relatively small number of building blocks and transform these into larger molecules. Chemical Basis of Life Fats - fuel reserve in fasting, hibernation or migration. Phospholipids - are fatty substances containing also phosphorous and nitrogen that are important in cell membrane. Ex. Lecithin in egg yolk Sterols - lipids which have complex molecules. - with three 6-Carbon rings; one 5-Carbon rings and at least one OH radical. Ex. cholesterol, calciferol (Vit. D), sex hormones, certain cancer- producing substances Chemical Basis of Life Proteins - are polymers composed of many molecules of amino acids (monomers). - most abundant organic material in the protoplasm. Function: - enzymes, structural proteins, storage protein, transport proteins, hormones, proteins for movement, protection and toxins. The basic amino acid form has a carboxyl group on one end, a methyl group that only has one hydrogen in the middle, and a amino group on the other end. Attached to the methyl group is a R group. Chemical Basis of Life Human body: - 70% water - ½ of the 30% is protein Peptide linkages - joined the amino acids to form protein molecules. Protein specifity - no 2 species of living organisms contain exactly the same type of protein. - lead to complication (foreign proteins) may cause illness or death Ex. Pollens may cause allergy in human Blood transfusion Cell as the Unit of Life Cell - is the basic structural and functional unit of life. Brief History on Cell Biology: before 17th century - no one knew that cells existed (most cells are too small to be seen by the unaided eye). until the discovery and invention of the microscope Brief History on Cell Biology Zacharias Jansen (1590) - spectacle maker in Holland - 1st to invent the compound microscope Robert Hooke (1665) - observed minute partitions separating cavities in the thin slices of cork. cork observed by Hooke cells Brief History on Cell Biology - Dutch drapery store owner - made the 1st handheld microscope - 1st to describe microscopic organisms and living cells. Anton von Leeuwenhoek Brief History on Cell Biology Mirbel (1808) plants formed by membranous cellular tissue. Lamarck (1809) animals Brief History on Cell Biology Robert Brown (1833) - described the nucleus as the central feature in plant cells. Brief History on Cell Biology Matthias Jacob Schleiden (1838) - German Botanist did a collaborative study on the microscopic investigations on the similarity of the structure and growth in animals & plants. Theodor Schwann (1839) - German Zoologist Brief History on Cell Biology - induced that “the animal arises only from an animal and plants arises only from a plant”. Rudolf Virchow Modern Cell Theory: ❖ cells are the basic unit of life. ❖ all organisms are made of one or more cells. ❖ all cells arise from preexisting cells. Prokaryotic and Eukaryotic Cells Cell structure: 1. Prokaryotic cells - lack a well-defined nucleus & most organelles. Prokaryotic and Eukaryotic Cells Cell structure: 2. Eukaryotic cells - have definite nuclei as well as the cell organelles. Organelles - discrete, membrane-bound, organized protoplasmic structures where the actual metabolic processes in the cell occur. Prokaryotic and Eukaryotic Cells Comparison of Prokaryotic and Eukaryotic Cells Prokaryotic cells Eukaryotic cells Structure Animal cell Plant cell Cell membrane yes yes yes Cell wall yes no yes Nucleus no yes yes Chromosomes one circular many many strand of DNA Ribosomes yes (small) yes (large) yes (large) Endoplasmic reticulum no yes yes Golgi apparatus no yes yes Lysosomes no yes yes Vacuoles no small or none yes Mitochondria no yes yes Chloroplasts no no yes Cytoskeleton Flagella only yes yes Components of the Eukaryotic Cell and their Functions Cell membrane or plasma membrane - bound the cell and regulate the passage of substances in and out of the cell. - made up of proteins and lipids (phospholipids) carry an electric charge Components of the Eukaryotic Cell and their Functions Membrane: 1. Unit of Membrane - by Davson and Danielli (1935) - tripartite arrangement of the plasma membrane. - lipid layer is sandwich between inner and outer layers of protein. Components of the Eukaryotic Cell and their Functions 2. Fluid Mosaic Model - there are two kinds of proteins present. 1. Loosely bound to the membrane 2. Integral proteins (penetrate into the lipid layers and serve as passage for the movement of substances. move about in the membrane like slow-moving ships at the sea. Components of the Eukaryotic Cell and their Functions Transport Mechanism: 1. - molecules seeking passage becomes associated with a carrier (will transport it across the membrane). 2. - substances move against the concentration gradient. Components of the Eukaryotic Cell and their Functions Components of the Eukaryotic Cell and their Functions 3. Pinocytosis - similar to phagocytes where cells engulf particles. - molecules rest on the surface of the membrane then the membrane folds over it in a vacuole or vesicle which moves into the cell. Components of the Eukaryotic Cell and their Functions Organelles: 1. Mitochondria - spherical to rod-shaped, bounded by a double membrane. - powerhouse of the cell. -- involve in the liberation of useful energy. -- Components of the Eukaryotic Cell and their Functions 2. Nucleus - the largest organelle and the most prominent which is bounded by a nuclear envelope with pores. - control center of the cell, initiating and monitoring function. Components of the Eukaryotic Cell and their Functions Chromatin - network of dark-staining fine stranded threads. chromosome - contains the DNA Components of the Eukaryotic Cell and their Functions 3. Endoplasmic reticulum - network of membranes and continuous with the nuclear pores. 1. Rough ER with ribosomes for CHON synthesis as well as a means of communication (channeling of products). 2. Smooth ER with/o ribosomes that synthesize and secrete certain steroid hormones, enzymes for CH2O & CHON metabolism. Components of the Eukaryotic Cell and their Functions 4. Golgi complex - for packaging and moving of the product materials in the cell. - closely associated with ER. Components of the Eukaryotic Cell and their Functions 5. Microbodies - spherical bodies bounded by single membrane. A. Peroxisomes – in the leaves that contain complex oxidative enzymes. B. Glyoxysomes – in the castor bean seed that contain complex oxidative enzymes. C. lysosomes – in the liver of animals that contain the lysozymes. - waste disposal system, digesting and removing foreign materials. Components of the Eukaryotic Cell and their Functions 6. Microtubules - formed by molecules of protein tubulin that formed the spindle fibers of dividing cells. Components of the Eukaryotic Cell and their Functions 7. Centrioles - seem to function sometime in mitosis. Components of the Eukaryotic Cell and their Functions 8. Microfilament - important in providing motive force for cell contraction and possibly intracellular transport. Components of the Eukaryotic Cell and their Functions 9. Plastid - where carbohydrate metabolism is localized. - pigment-containing organelle. A. Chloroplast – contain the chlorophyll (green) Components of the Eukaryotic Cell and their Functions B. Chromoplast– with dominance of red & yellow pigment (carotenoids) C. Leukoplast – colorless plastids that function for storage and synthesis of a variety substances.  Non-protoplasm portion of the plant cell: Components of the Eukaryotic Cell and their Functions 10. Vacoule – bounded by tonoplast that contain various substances (atmospheric gases, inorganic salts, sugars, water- soluble pigments and others) A. Anthocyanin – red, purple and blue color of petals B. Anthoxanthin – yellow coloration of puppy flowers C. Betacyanin – red color of roots and leaves  CELL DIVISION Cell Cycle and Reproduction -- cells are born, live for a while and then reproduce -- Cell Cycle and Reproduction I. Interphase - period of growth and preparation for reproduction. - internal and chemical changes occur. Cell Cycle and Reproduction INTERPHASE: G1 phase - the newly produced daughter cell increases in size and undergoes internal chemical changes which somehow prepares it for DNA replication. S phase - period that DNA replication or synthesis occur. G2 phase - preparatory stage prior to the beginning of active mitosis. - certain proteins are produced necessary to cell division. Cell Cycle and Reproduction II. Mitosis - reproductive period by which cells actively divide. - shows morphological changes. - ensure the continuous succession of identical cells. Cell Cycle and Reproduction MITOSIS: - physically divide the cell into 2 daughter cells and ensure that each has exactly the same complement DNA. - cause morphological changes. Cell Cycle and Reproduction 1. Prophase - condensation of the chromatin granules of the nucleus into visible long threads called chromosomes. colored body, composed of sister chromatids that contain DNA. guide the movement of the chromosome - appearance of centromere (kinetochore) - nucleolei gradually disappear - nuclear envelope breaks down, freeing the chromosomes - complete formation of the spindle Cell Cycle and Reproduction 2. Metaphase - chromosomes become aligned midway between the 2 poles of the spindle so that they lie in the equitorial plate. - chromosomes reached the maximum thickness Cell Cycle and Reproduction 3. Anaphase - aligned double chromosomes begin to separate towards the opposite poles. 4. Telophase - groups of daughter chromosomes reach the opposite sides of the cell. - reappearance of nucleolus & nuclear envelope. - cytokinesis occur cytoplasmic division Cell Cycle and Reproduction Significance of mitosis: - it ensures a continues succession of identical cells (duplication of DNA) - produce two diploid daughter cells Meiosis - occurs only in germ cells. - genetic material of the parent cell is halved in each daughter cell. - produce haploid daughter cells Cell Cycle and Reproduction spermatogenesis: - DNA & acrosome is concentrated at the head. - lysins (for dissolving egg membrane) Cell Cycle and Reproduction Pattern of Inheritance MENDEL’S Laws 3. Law of Independent Assortment ❑ Each pair of factors segregates (assorts) independently of the other pairs. ❑ All possible combinations of factors can occur in the gametes. members of one gene pair separate from each other independently of the members of the other gene pair. Pattern of Inheritance 3. Law of Independent Assortment Pattern of Inheritance Non – Mendelian Pattern of Inheritance 1. Incomplete dominance - the condition in heterozygotes where the phenotype is intermediate between the two homozygous type. Ex. Flower petal red (RR) white (rr) pink (Rr) pink (Rr) red (RR) pink (Rr) pink (Rr) white (rr) Phenotypic ratio: 1:2:1 Pattern of Inheritance Incomplete dominance: Pattern of Inheritance Non – Mendelian Pattern of Inheritance 2. Codominance - the condition in heterozygotes exhibits a mixture of the phenotypic characteristics of both homozygotes, instead of a single intermediate expression. Pattern of Inheritance Non – Mendelian Pattern of Inheritance 2. Codominance Phenotypic ratio: 1:2:1 Pattern of Inheritance Non – Mendelian Pattern of Inheritance 3. Lethal genes - whose effect is sufficiently drastic to kill the bearer of certain genotypes. Chromosomal Mutation: Changes in the Chromosome Structure Changes in genetic material that involve entire chromosomes or piece of them Occurs during cell division: mitosis and meiosis Involves many genes Caused by: Various agents in the environment Radiation X – rays, ultraviolet radiation Certain organic chemicals Drugs, coal – tars in some hair dyes Chemicals in smoked and charcoal broiled meats virus Chromosomal Mutation: Changes in the Chromosome Structure Deletion Syndromes Williams syndrome occurs when chromosome 7 loses a tiny end piece look like pixies, with turned-up noses, wide mouths, a small chin, and large ears. Although their academic skills are poor, they exhibit excellent verbal and musical abilities. Chromosomal Mutation: Changes in Chromosome Structure Duplication is the presence of a chromosomal segment more than once in the same chromosome may or may not cause visible abnormalities, depending on the size of the duplicated region Chromosomal Mutation: Changes in Chromosome Structure Inversion occurs when a piece of chromosome breaks loose and then rejoins in the reversed direction May cause no change, because it involves no change of genes Leads to babies with birth defects and/or abnormal development Increased risk for miscarriage Chromosomal Mutation: Changes in Chromosome Structure Translocation A translocation is the movement of a chromosome segment from one chromosome to another, nonhomologous chromosome. Chromosomal Mutation: Changes in Chromosome Structure Translocation Syndromes Alagille syndrome Practical Applications of DNA Technology 1. Medicine and the Pharmaceutical Industry: a. Diagnosis of diseases b. human gene therapy c. pharmaceutical products 2. Forensic, environmental, and agricultural applications a. Forensic use of DNA technology b. Environmental use of DNA technology a. Agricultural use of DNA technology Animal husbandry and “pharm” animals Genetic engineering in plants Practical Applications of DNA Technology Genetic engineering - is any process by which genetic material (the building blocks of heredity) is changed in such a way as to make possible the production of new substances or new functions. requires three elements The gene to be transferred a host cell into which the gene is inserted a vector to bring about the transfer Practical Applications of DNA Technology The Process of Genetic Engineering Practical Applications of DNA Technology Techniques in Genetic Engineering ✓ Selective Breeding - First known genetic engineering technique - Breeding of plants and animals to produce certain desired traits in the next generation of offspring ✓ Hybridization ✓ Cloning Practical Applications of Technology Techniques in Genetic Engineering ✓ Recombinant DNA (rDNA) is called “gene splicing” - inserting one or more genes from one organism into different organism bacteria into a plant of from one species into another. - Recombination is the process through which a new gene is inserted into a bacterial DNA "The plasmid". Practical Applications of DNA Technology Genetic Modification in Plants Genetically modified crops (GM crops) are those engineered to introduce a new trait into the species. Proposes: resistance to certain pests, diseases, or environmental conditions, or resistance to chemical treatments (e.g. resistance to a herbicide). to enhance its nutritional value in the Production of golden rice case of golden rice. done through genetic engineering Vitamin “A” enriched Practical Application of DNA Technology Genetic Modification in Animals Genetic modification of an animal involves altering its genetic material by adding, changing or removing certain DNA sequences in a way that does not occur naturally. It aims to modify specific characteristics of an animal or introduce a new trait, such as disease resistance or enhanced growth.