Gen Bio Reviewer PDF

GEN BIO REVIEWER LESSON 1: PROPONENTS OF CELL THEORY Robert Hooke – microbiologist in 1600s - He wrote a very famous book called Micrographia which contained detailed drawings of small as a flee. - He 1st viewed the cells under the microscope in 1665. - He called these room-...

GEN BIO REVIEWER LESSON 1: PROPONENTS OF CELL THEORY Robert Hooke – microbiologist in 1600s - He wrote a very famous book called Micrographia which contained detailed drawings of small as a flee. - He 1st viewed the cells under the microscope in 1665. - He called these room-like structures in cork cell. He was the first to use the term cell to refer to tiny structures. ANTONIE VAN LEEUWENHOEK - linen merchant in the town of Delft. - He created his own viewing machine. - He discovered bacteria and called it animalcules. - He was the first man to view human sperm cell. THEODOR SWANN – animal biologist. - During his research, he kept finding the same global structure, red blood cells. MATTHIAS J. SCHLEIDEN – a plant biologist. - He spoke passionately with Schwann about his research and how the cells made up and in return schwann revealed his work on the nerves of the edible frog and they figured out that they are both made of the same material-cells. ROBERT REMAK – first one to witness cell division. - He discovered that RBC have been splitting into two - Remak changed his approach and he used egg frogs for his experiments. RUDOLF VIRCHOW – he took all the credits of Remak’s research. - He created his own phrase “all cells from other cells” THE CELL THEORY 1.) All living organisms are composed of one or two cells – one cell are called unicellular or single celled organisms. Ex. Bacteria and protozoans. - More than one cell is called multi-cellular or multi-celled organisms. 2.) A cell is the basic unit of life – the cell is a completely functional entity. - Biological processes cannot occur without the presence of cells. - Cells are the building blocks of every system in living things. 3.) All cells came from preexisting cells – cells cannot be spontaneously created but a product of reproduction of for preexisting cells. This postulate of theory refers to cell division. Cell division can be different types like fission or budding in yeast cells, mitosis and meiosis in plant and animal cells, and human cells. 4.) Energy flow occurs within cells – chemical energy is produced from thousands of biochemical reactions that take place inside the cell. 5.) Hereditary information or DNA is passed on from one cell to another – the process results in the parent cell passing on its genetic content or DNA to the offspring. THE MODERN CELL THEORY Chromosomes that contain genetic material is passed on from parents cells to daughter cells. 6.) All cells have the same basic composition – Almost all cells are surrounded by a cel wall an filled with a fluid like substance known as cytoplasm or cytosol in which organelles ae present. LESSON 2: CELL ORGANELLES (SUBCELLULAR) A. Cell wall – protects the plasma membrane Pass freely into and out of the cell Absorb H2O into the vacuole and swell without bursting. Prokaryotes, fungi and protists also have cell walls. B. Vacuole – membranous sacs larger than vesicles Store materials that occur in excess. Have central vacuole, up to 90% volume of some cell. Storage of water, nutrients, pigments and waste products. Turgor pressure C. Cytoskeleton – maintains shape and gives support to cell. Not a static structure but is able to disassemble and reassemble for overall cell mobility. Assists in transportation of communication signals between cells. It forms cilia and flagella in some cells. D. Peroxisome – similar to lysosomes, membrane-bounded vesicles, enclosed enzymes. Free ribosomes in cytoplasm, active in lipid metabolism, produces hydrogen peroxide H2O2 Broken down to water and O2 by catalase E. Golgi Apparatus – Golgi bodies or Golgi complex, stacks of flattened vesicles, forms secretory vesicles, packages protein for export Collection, packaging and distribution of molecules. F. Endoplasmic Reticulum – connecting link between nucleus and cytoplasm of the plant cell. 2 types Rough endoplasmic reticulum – studded with ribosomes, protein anabolism Smooth endoplasmic reticulum – no ribosomes, synthesis of lipids, detoxification and storage, for transport vesicles. G. Centrioles – short, hollow cylinders 27 microtubules, 9 overlapping triplets One pair per animal cell, located in centrosome, oriented at right angles to each other, separate during mitosis, may rise to basal bodies of cilia and flagella. Lesson 3: PROKARYOTIC AN EUKARYOTIC CELLS 1.) Prokaryotes – single celled organisms that are the earliest and most primitive forms of life. ( 0.1-5.0 micrometer ) Smaller size compared to eukaryotes that allows ion to enter them and quickly diffuse. Many are extremophiles and can thrive in extreme environments. a.) Domain Bacteria – (eubacteria/true bacteria) Prokaryotic cells can be found almost everywhere. Unbranched fatty acid chains attached to glycerol. Cell wall contains peptidoglycan, sensitive to antibacterial antibiotics but resistant to others, contains rRNA. b.) Domain Archaea - Single celled, no cell nucleolus, lives in extreme environments such as permafrost Composed of branched hydrocarbon chains attached to glycerol. No peptidoglycan Not sensitive to antibiotics and contains rRNA that is unique. COMPONENTS OF PROKARYOTIC CELLS 1.) Capsule – assists in retaining moisture and helps cell adhere to surfaces and nutrients. 2.) Plasma membrane – surrounds the cell cytoplasm, regulates the flow of substances I and out of the cell.  3.) Ribosome – protein production 4.) Cell wall – outer covering that protects bacterial cell and gives it a shape. 5.) Pili – hair-like structures 6.) Flagella – long whip-like protrusion that aids locomotion 7.) Nucleoid region – single bacterial DNA molecule 2.) Eukaryotes – cells are organized into comples structures Much larger in size ranging from 10-100 micrometers in diameter Developed different structural adaptations Most characteristic is nucleus, examples are animals, plants, fungi, and protists. FORMS FOLLOWS FUNCTIONS Derived from the famous saying of skyscraper architect Louis Sulivan, “form ever follows functions”. Structure and function go hand in hand, where disruption of one aspect can lead to failure in another. LESSON 4: CELL TYPES 1.) STEM CELLS – have the power to replicate into healthy cells. The process that allows term cells to transform into any kind of cell is called Cell Differentiation. I. 2 types of Stem cell Adult Stem (somatic stem cell) – to repair and maintain surrounding specialized tissues. Stem cells can generate diff cell types. Embryonic Stem Cell – pluripotent, the ability to differentiate into almost all cell types. They are obtained from early-stage embryo- a group of cells that forms when woman’s egg is fertilized with a man’s sperm. 2.) BLOOD CELLS - Red Blood cells – erythrocytes, red blood corpuscle. Shaped like biconcave disc. Transport oxygens using hemoglobin - White Blood Cell – leukocytes, white blood corpuscle, vital component of the immune system. TWO MAIN CATEGORIES OF WBC 1.) Granulocytes – contains granules. a.) Neutrophils- most common type of white blood cell, irregular nuclei, they kill germs by phagocytosis or cell eating. b.) Eosinophils – specialized enzyme histaminase c.) Basophils – least frequent type, ability to secrete anticoagulants and antibodies d.) Natural killer cell – kill tumor cells or cells infected with virus, senses stressed cells, seek them out and destroy them. 2.) Agranulocytes – have no granules a.) Monocytes – larg kidney bean shaped nucleus, circulates in bloodstream, Macrophages - are cells that engulf and kill dead cells and bacterial cells. b.) Lymphocytes – B-CELLS and T-CELLS T-Cells (T Lymphocytes) – helper cells and killer cells, named from thymus, produced in the bone marrow and moves to thymus when matured. 1.) Helper T Cells – activate B cells and killer T cells. 2.) Killer T Cells (Cytotoxic T Cells) – attacking cells. 3.) T Memory Cells – produce memory cells with longer life span than B Cells. B Cells (B lymphocytes) – make antibodies which are the final step of disease resistance.  1.) Plasma Cells- produce antibodies, seek out intruders. Antibodies neutralize toxins and incapacitate viruses. 2.) B memory Cells – have prolonged life span, “remember specific intruders”, B and T cells help the immune system to activate much faster. 3.) Platelets– thrombocytes - Fragments of cells, they undergo fragmentation or clonal fragmentations. 3.) NERVE CELLS (NEURONS) – transmit informations throughout the body 4.) NEUROGLIAL CELLS– glial cells or glia, cells of the nervous system. 4 Types Astrocytes – star-like appearance, maintenance of the chemical environment for signal. Oligodendrocytes- forms lipid-rich myelin sheath around axons. Microglial Cells- removal of debris from sites of injury. Ependymal cells- line those ventricles and central anal of the brain to produce cerebrospinal fluid. 5.) MUSCLE CELLS– myocytes, present in muscle tissue, rich in proteins Actin and Myosin. It has 3 types, Skeletal, Cardiac, and Smooth Muscle cells. 6.) BONE CELLS Osteoclast- Bone Resorption, breaks don bone forming sealed compartments on its surface. Osteoblasts- generation of new bone known as Bone Remodeling Osteocytes – growth factors, activate bone growth Lining cells- lines the surface of the bone, release of calcium. 7.) SKIN CELLS Keratinocytes- generates the protein keratin, blocking toxins and pathogens. Melanocytes- produce pigment melanin which determines skin coloration. Merkel cells- mechanosensory cells and are involved in touch reception. 8.) SEX CELLS – sexual reproduction in the form of fusion called gametes. 9.) PLANT CELLS Parenchyma Cells- typical plant cel, stores organic products. -photosynthesis -storage of air -storage of water and minerals. TYPES - Palisade Parenchyma – performs photosynthesis where the rate is very ahigh. -Spongy Parenchyma- air storage. Collenchyma Cells- supports plants while not restraining growth. Sclerenchyma Cells- have a hardening agent. LESSON 5: CELL MODIFICATIONS CELL MODIFICATIONS- specialization that is re-acquired by a cell after cell division. 1.) APICAL MODIFICATIONS- happen in the surface of epithelial cells. a.) Cilia- Slender, microscopic hair-like structures 1.) MOTILE CILIA- used for locomotion in organisms, found in the lining of the trachea 2.) NON-MOTILE CILIA- occur one per cell, have a single non-motile primary cilium. a.) Mechanoreceptors- lining the kidney tubules and monitors the flow of fluid through the tubules.  b.) Chemoreceptors- detect odors c.) Photoreceptors- outer segment of the rods in the vertebrate retina. b.) Flagella- is a whip-like appendage, flagellum in Latin means whip. Functions: movements, sensation, signal transduction, adhesion. TYPES OF FLAGELLA 1.) Monotrichous- single polar flagellum 2.) Amphitrichous- single flagellum on both sides 3.) Lophotrichous – tufts of flagella at one or both sides. 4.) Peritrichous- numerous flagella all over the bacterial body. c.) MICROVILLI- fingerlike outward Functions: absorption in intestine, secretion, cellular adhesion, mechanotransduction in kidney proximal tubules. 3.) BASAL MODIFICATIONS- occurs in the cells that are attached in the basal lamina. 4.) LATERAL MODIFICATIONS- strong that cells are attached tightly with one another. d.) Pili- enables a bacterium to adhere to the tissue surfaces or host surfaces. e.) Dendrites and Axon- bring information to the cell body f.) Actin o myosin- permits the muscle to contract and elongate. g.) Red Blood cells or Erythrocytes- they do not have nucleus but have large amounts of hemoglobin to transport oxygen. h.) Root Hairs- specialized epidermal cells of plants that increase the apparent area of roots. i.) Spores- defense mechanism to heat, high pressure, and strss, contains 30% water. LESSON 6: CELL CYCLE (PHASES) CELL DIVISION- the process cells go throughto divide, have evolved over time. 1.) Binary Fission- simple organism with only one membrane and no division internally. 3 main types a.) DNA REPLICATION- 2 identical chromosomes b.) CHROMOSOME SEGREGATION- 2 chromosomes separate, move towards ends. c.) Cytokinesis- cytoplasm divides, forming 2 cells. CELL DIVISION OF EUKARYOTES 1.) MITOSIS- division of somatic cells of eukaryotic organisms, somatic are all cells of the body except sperm and egg. 2.) MEIOSIS- produces gametes, sperm or eggs, cell cycle is the complex sequence of events. The stages of the cell cycle are divided into two major phases: 1.) INTERPHASE- cell grows and makes a copy of its DNA. -preparation for division which happens in 3 stages a.) G1 PHASE- cell grows and more organelles are produced. - accumulating the building blocks of the chromosomal DNA b.) S PHASE - DNA replication can proceed the mechanisms that results in the formation of the identical DNA molecules (sister-chromatids). - the centrosome is duplicated, with a pair of rod-like objects (centrioles). c.) G2 PHASE- replenishes its energy stores and synthesizes proteins. - cell organelles are duplicated, cytoskeleton is dismantled. - Additional cell growth 2.) MITOTIC (M) PHASE- cell separates its DNA into two sets and divides its cytoplasm. a.) MITOSIS- nuclear DNA of the cell. 4 STAGES are PROPHASE, METAPHASE, ANAPHASE, TELOPHASE  b.) CYTOKINESIS- cytoplasm of the cell is split in two. c.) G0 PHASE- are not actively preparing to divide. - Never or rarely divide such as mature cardiac muscle and nerve cells, permanently remain in G0. LESSON 7 Checkpoint is a stage in the eukaryotic cell cycle which examines internal and external cues - decides whether or not to move forward with division Cell Cycle Checkpoints 1.) G1 Checkpoint - G1/S transition 2.) G2 Checkpoint - G2/M 3.) Spindle or M checkpoint - metap-anap G1 - Restriction point determines whether all conditions are favorable to proceed. - it halts the cycle and can advance into G0 until conditions improve. Requirements: Size, Nutrients, Molecular Signal, DNA integrity. G2 - bars entry to mitotic phase - if damage is irreparable it may undergo APOPTOSIS. Requirements: DNA integrity, DNA replication M Checkpoint - Spindle Checkpoint occurs near the end of metaphase stage of Karyokenisis. Requirements: sister chromatids are correctly attached to spindle microtubules. Positive Regulations - two groups of cyclins and cyclins-dependent-kinases (Cdks) - responsible for progress of the cell -the cycle that were active in the previous stage are degraded. - cyclins regulates only when tightly bound to Cdks. -Cdks complex must be phosphorylated -CDK INHIBITORS ARE MOLECULES THAT PREVENT THE FULL ACTIVATION OF CDKS. Negative Regulations - halts the cell cycle Types: p53, p51, retinoblastoma P53- munlti functional protein that acts when there is a damage DNA in cells during G1. - it recruits enzymes to repair damage DNA. -they can trigger apoptosis if cannot repair. P51-enforces the halt in cell cycle, inhibits and binding the activity of CDK. -it will move to S phase if exposed to higher level of p51 and p53. Retinoblastoma- monitors cell size. - turn on specific genes allowing proteins, when Rb is bound to E2F proteins are necessary for the G1/S TRANSITION to be blocked. -Rb releases E2F can turn on the gene and the block is removed. LESSON 8 P1: CELL CYCLE (MITOSIS) WHY CELLS DO DIVIDE? 1. REPAIR OR REPLACEMENT- intestinal cells have to be replaced as they wear out. 2. Reproduction- yeast cells need to reproduce to keep their population growing. 3. Growth and Development - tadpole must make new cells as it grows bigger. 4. Maintenance of Surface Area to Volume Ratio Mitosis - one cell divides to produce two new cells that are genetically identical to itself. -nucleus is split into two equal sets of chromosomes. -to make sure that each daughter vells gets a perfect full set of chromosomes. Four Basic Phases 1. Prophase - starts to break down some structures, chromosomes start to condense, organized chromosomes and move them around. It grows between the centrosomes. - the nucleolus disappears signs that the nucleus is getting ready to break down. 2. PROMETAPHASE- spindle begins to capture and organize the chromosomes that finished condensing so they are very compact. 3. METAPHASE- captured all chromosomes and lined them up at the midlle of the cell to divide. - all chromosomes align at metaphase plate. 4. ANAPHASE - sister chromatids separate and are pulled towards opposite ends of the cell. - protein glue is broken down, allowing them to separate. 5. TELOPHASE- nearly done dividing and starts to re-establish its normal structurez as cytokinesis takes place. -2 nuclei from, chromosomes return to their stringy form. CYTOKENISIS- division of cytoplasm, overlaps with telophase. - drawstring is band of filaments made of protein called actin. -Plant Cells cant be divided like animal crlls because thry have cell wall. Significance of Mitosis for sexual reproduction - to continue to reproduce through the generations. MEIOSIS - requires fertilization, contains two sets of chromosomes. - Haploid Cells contains one set of chromosomes, Cells containing two sets of chromosomes are called Diploid. -the number of sets of chromosomes in a cell is called its ploidy level. a.) Meiosis I - first round of meiotic division that consists of prophase 1, prometaphase 1, and so on.  G1 phase- focus on cell growth S phase - DNA of the chromosomes is replicated. G2 phase- cell undegoes the final preparations for meiosis. Propase I - nuclear membrane breaks down, centrioles nad centrosomes begin to move, spindle fiber starts to assemble. Metaphase I - align the homologous chromosomes in metaphase plate, equator has chromosomes from both parents, the maternal and paternal genes are recombined by crossover events between non sister chromatids. Anaphase I - paired homologous chromosomes separate from each other, sister chromatids remain attached. Telophase I- spindle fibers disassemble, cytokenisis. CENTROSOMES DUPLICATE BETWEEN MEIOSIS I AND II b.) Meiosis II - second round that includes prophase II, prometaphase II, and so on. Prophase II - move to opposite side of the cell and spindle fibers start to assemble, nuclear envelope breaks down. metaphase II- chromosomes line up individually, sister chromatids separate. telophase II- nuclear membrane forms around, cytokenisis splits the chromosome sets into new cells. IN HUMAN, PRODUCTS OF MEIOSIS ARE SPERM AND EGG CELLS. HOW MEIOSIS MIX AND MATCH GENE? gametes are all haploid, but not genetically identical. 2π equal to 46 chromosomes. THE 3 MAIN REASONS WE CAN GET MANY GENETICALLY DIFFERENT GAMETES ARE 1. CROSSING OVER 2. RANDOM ORIENTATION OF HOMOLOGUE PAIRS 3. RANDOM FERTILIZATION. SPERMATOGENESIS 1. spermatogonia are activated by secretions of testosterone. 2. spermatogonium divides through mitosis 3. one of the daughter cells is spermatogonium, the other is spermatocyte. 4. spermatocyte undergoes meiosis to produce two smaller secondary spermatocytes with 23 chromosomes. 22 chromosomes 1X AND 1Y SEX CHROMOSOMES 5. secondary spermatocyte undergo second meiotic division. 6. develop into mature sperm, spermatogenesis takes about 64 days. OOGENISIS, SIGNIFICANCE-