General Biology 1 PDF

GENERAL BIOLOGY 1 ORGANELLES are little organs. Zacharias Janssen (1590) CELL ORGANE...

GENERAL BIOLOGY 1 ORGANELLES are little organs. Zacharias Janssen (1590) CELL ORGANELLES - He invented the very first microscope. Function - Compound Microscope Production of protein. Robert Hooke (1665) Storage of important materials. - He coined the term “cellular” which was shortened to cell for the thin slice of cork he observed through viewing Harvesting energy. it in a microscope. Preparing cell parts. Anton Van Leeuwenhoek (1674) Digestion of substances. - He observed the animalcules from the pond water Maintaining shape and structure of the cell. which were later found to be bacteria, protozoans, and small animals. THREE MAJOR PARTS OF THE CELL Matthias Schleiden (1838) Cell Membrane - He proposed that all plants are made of cells. Cytoplasm Theodore Schwann (1839) Nucleus - He defined the cell as the basic unit of animal CELL MEMBRANE structure. ➤ Encloses the cell and separates it from external Rudolf Virchow (1858) environment. - He concluded that cell is the basic unit and structural ➤ Referred as fluid mosaic. unit of life and that every cell is formed from a preexisting cell. ➤ Selectively permeable. ➤ Made up of phospholipid. CELL THEORY CYTOPLASM 1. All living things are composed of one or more cells. ➤ Jelly-like substances (cytosol) which us mainly composed of water with dissolves substances. 2. Cells are the basic unit structure and function in living things. ➤ This is where the other ORGANELLES are suspended 3. All cells arise only from preexisting cells. dynamically. MODERN CELL THEORY NUCLEUS 4. Cells carry genetic materials which is passed from cell ➤ The “control center” of the cell. to cell during cell divisions. ➤ It tissues the genetic material. 5. All cells are basically the same in structure and ➤ It has nucleolus, where the subunit of ribosomes are chemical composition. assembled. 6. Energy flow (biochemical processes) occurs within cells RIBOSOMES PROKARYOTES ➤ Site for protein synthesis. are single-celled organisms that lack a membrane- bound nucleus, mitochondria, and all other organelles. ➤ Free Ribosomes and Attached Ribosomes. PARTS AND FUNCTIONS OF PROKARYOTIC CELL Free Ribosomes: Cytoplasm NUCLEOID Attached Ribosomes: Rough Endoplasmic Reticulum ➤ A central region of the cell that contains it's DNA. ➤ Protein is import inside the cell. RIBOSOME ENDOPLASMIC RETICULUM ➤ Ribosomes are responsible for protein synthesis. ➤ Serves as the transport system of the cell (like a highway) CELL WALL ➤ Two types: ➤ The cell wall provides structure and protection from the outside environment. Most bacteria have a rigid cell Smooth ER: without ribosomes for lipid synthesis wall made from carbohydrates and proteins called Rough ER: with ribosomes. peptidoglycans. GOLGI BODIES CELL MEMBRANE ➤ Involved in modifying, sorting, and packaging of ➤ Also known as the plasma membrane. It separates the macromolecules. cell from the outside environment. CAPSULE ➤ For delivery to another organelles. LYSOSOMES ➤ The capsule is a layer of carbohydrates that helps the bacterium attach to surfaces. ➤ Suicide sacs. FLAGELLA ➤ It plays a role in the destruction or repair of defective ➤ Flagella are thin, tail-like structure that assist in parts of the cell. movement. ➤ Exclusive for animal cells. PILI VACUOLES ➤ Rod-shaped structures involved in multiple roles, ➤ Storage sacs in the cell. including attachment and DNA transfer. ➤ In animal cells, it is use for storage of water and food, FIMBRIAE other for excretion of waste material. ➤ Thin-hair like structures that help with cellular ➤ In plant cells, it is very large. attachment. MITOCHONDRIA ➤ The power house of the cell. EUKARYOTES are organisms with cells that contain membrane-bound ➤ Site for cellular respiration. nucleus and other membrane-bound organelles. ➤ It creates energy by breaking down food materials. PARTS AND FUNCTIONS OF EUKARYOTIC CELL ➤ Adenosine Triphosphate NUCLEUS ➤ A useable format energy in the cell. ➤ Store the cells DNA, maintain its integrity, and facilitate it's transcription and replication. RIBOSOMES DIFFERENCES ➤ Ribosomes are responsible for protein synthesis. Prokaryotic cells are the primitive kind of cell, whose size varies from 0.5-3μm, they are generally found in CELL WALL single-cell organisms. ➤ It is a protective layer that proctects the cell from any Eukaryotic cells are the modified cell structure injury or pathogen attacks. containing different components in it, their size varies CELL MEMBRANE from 2-100μm, they are found in multicellular organisms. Organelles like mitochondria, golgi body, endoplasmic ➤ It comprises specific embedded proteins, in the reticulum, chloroplast, etc., are absent in Prokaryotic exchange of subs in and out of the cell. cells. MITOCHONDRIA These organelles are found in Eukaryotic organisms. ➤ These are also known as “powerhouse of the cells” Though cell wall and chloroplast are not found in animal they produce energy. cell, it is present in the green plant cell, few bacteria, and algae. ENDOPLASMIC RETICULUM The main difference between Prokaryotic cells and the ➤ The endoplasmic reticulum either be smooth or rough Eukaryotic cells is the nucleus, which is not well defined in general it's function is produce proteins for the cell to in Prokaryotes whereas it is well structured, function. compartmentalized, and functional in Eukaryotes. VACUOLE Cell ogranelles are present which are membrane- bound and have individual functions in Eukaryotic cells; ➤ Helps with sequestering waste products and maintain many organelles are absent in Prokaryotic cells. water balance in animal and plant cells. In prokaryotes, the cell division takes place through LYSOSOMES conjugation, transformation, and transduction. ➤ Helps break down excess or worn-out cell parts. They In Eukaryotes, it is through the process of cell division. may be used to destroy invading viruses and bacteria. The process of transcription and translation occurs GOLGI APPARATUS together, and there is a single origin o replication in the ➤ Functions as a factory in which proteins received from Prokaryotic cell the ER are further processed and sorted for transport to On the other hand, there are multiple origins of their eventual destinations. replication and transcription occurs in nucleus and SIMILARITIES translation in the cytosol. Plasma Membrane, an outer covering that allows Genetic Material (DNA) is circular and double- selective entry and exit of substances in and out of the stranded in Prokaryotes. cells found in both cell types. In Eukaryotes, it is linear and double-stranded. Both contain cytoplasm, a jelly-like fluid that fills the Prokaryotes reproduce asexually. cell's entire interior where all other cellular components are found. Commonly Prokaryotes have a sexual mode of reproduction. DNA is the genetic material in both cell types. Prokaryotes are the simplest, smallest, and most In both ribosomes help in protein synthesis. abundantly found cells on earth. Eukaryotes are larger and complex cells.  PLANT AND ANIMAL CELL Plant Cells Plant tissues - groups of cells with a common structure, Plants are eukaryotic organisms whose cells acquire function, or both. The key tissues among plants are the specialized functions as they mature. vascular, dermal and ground tissues. Types of Cells in Plants Plant Tissues Parenchyma They compose the middle layer of Dermal Tissues Outer protective covering of plants. Cells leaves and the inner and outer Ground Tissues Tissues which are neither vascular layers of stems and roots. Soft nor dermal, they are for storage of tissues of fruits are also made carbohydrates which plants need form parenchyma cells. for growth. Generally have large central Vascular Tissues Group of cells that conduct the vacuole. movement of nutrients and water. Perform most of the metabolic functions of the plants, synthesizing, storing various products The fleshy tissue of many fruits is composed mainly of parenchyma cells. Collenchyma They are elongated cells with thick cells cell wall whose main functions are for support and structure especially in young plants (young stems and petioles). They provide flexible support without restraining growth Sclerenchyma They also have a support function cells but are much more rigid than collenchyma cells. They are thick Dermal Tissues and come in many shapes. The cells that compose dermal tissues serve as the outer There are two types of protective layer of plants. By way of analogy, they are like sclerenchyma cells the skin of plants which serve as the first layer of 1.Sclereids protection against harmful elements of the environment. 2. Fibers Components of Dermal Tissues Epidermis A single layer of tightly packed cells that Types of sclerenchyma cells cover and protects the plant. Sclereids There are two types of sclerenchyma cells Periderm Commonly referred to as the bark, it is a Sclereids, which are boxier and irregular in multi- layered dermal tissue composed shape, have very thick, lignified secondary of cork cells (phellem), phelloderm, and walls. Sclereids impart the hardness to cork cambium (phellogen) nutshells and seed coats and the gritty textures to pear fruits. Fibers Usually grouped in strands, are long, Ground Tissue slender, and tapered. Such as hemp fibers Tissues which make up the plant but are neither vascular for making rope and flax fibers for weaving into linen. nor dermal tissues comprise the ground tissue. They can be found inside and outside the ring of vascular tissue in the plant stem. The three types of cells that compose the ground tissue are the parenchyma cells, collenchyma cells, and sclerenchyma cells.  Vascular Tissues They are the primary tissues of plants responsible for Basic Animal Cells the transport of nutrients and water. Skin Consists of keratinocytes and melanocytes. Cells Keratinocytes make up 90% of all skin cells. They are found only in vascular plants because they They produce a protein called keratin. have lignified tissues throughout the plant which allow Melanocytes produce melanin which gives the transport of substances. color to skin. Muscle Myocytes or muscle cells are long tubular The primary components of vascular tissue are the Cells cells that help organisms move their limbs xylem and the phloem and organs. Meristematic Tissues Blood Blood cells can be either red blood cells or Cells white blood cells. Red blood cells make up - Another prominent category of cells among plants is 99.9% of all blood cells and delivers oxygen the meristematic tissue. It is a collection of young cells to different parts of the body. White blood which are continuously reproducing through division. cells find and destroy pathogens and other harmful substances in the body. -They are mostly found ate the apices and are embedded Fat Adipocytes or lipocytes are storage cells for in the vascular tissues which contribute to the increase Cells fats and lipids which are reserves of energy. in the girth size of roots and stems Nerve Neurons are the main cells of the nervous Cells system. They carry messages & deliver MERISTEMATIC TISSUES BASED ON POSITION signals to different parts of the body using Apical Cells found at the growing regions of their dendrites & axon. Meristem roots and shoot and contribute to Bone Osteocytes are majority of cells embedded increase in length. Cells within the substance of a fully formed bone Lateral Cells found in the vascular tissues and Meristem contribute to the increase in thickness of a plant part. Epithelial Tissue Intercalary Cells found in regions between mature Meristem tissues of the plant such as at the base It forms a protective layer of cells for organs. They serve of leaves or at the base of internodes of as a barrier to keep the body systems separate. The most grasses. visible epithelial tissue is our skin which protects our internal organs from harmful agents of environment. Animal Tissues Types of Epithelial Tissue Based on Structure Simple Composed of a single layer of cells. It A group of cells in animals that share a similar structure epithelial functions as a lining of cavities, ducts, and perform the same function is called an animal tissue and tubes. tissue. Compound Composed of two or more layers of cells. epithelial It functions as a protective covering. Our TYPES OF ANIMAL TISSUE tissue skin is a compound epithelial tissue. Epithelial Covers body surfaces and lines body Tissue cavities, some epithelial cells secrete glands. Epithelial Tissues Based on Shape and Function Connective Binds and supports body parts. Squamous Flat & thin Found in the outer layer Tissue epithelium cells with no of the skin, in the lining Muscular Long cylindrical fibers arranged in intercellular of cavities, blood Tissue parallel arrays which allows the parts spaces vessels, and in the of the body to move. between chambers of the heart. Nervous Receives, processes, and transmits cells. Tissue information from one part of the body Columnar Cylindrical in Found in the lining of to another epithelium shape, it stomach and intestines facilitate the movement of nutrients  across phosphorous epithelial compounds. They barrier are hard & porous. Glandular It forms from Found in the sweat They anchor muscle epithelium a columnar glands of the skin and tissues, protect epithelial cell, tear glands of the eye. internal organs, & it secretes give mechanical substances. support to the entire Ciliated A columnar Found in the lining of the body. epithelium cell with hair- respiratory tract. Fibrous Ligaments connect Found in like connective two bones. Tendons ligaments and projections tissues connect bones to tendons. called cilia. (ligaments & the muscles. They Cilia push the tendons) add strength to mucus muscles. forward into Cartilage Widely spaced cells Found in nose, the nasal tract suspended in a ears, trachea, & to clear it. matrix of protein at the end of Cuboidal Cube- like in Found in the lining of and sugars. Adds long bones for epithelium shape, it kidney tubules, salivary mechanical support flexibility. provides glands, & thyroid glands. and flexibility. mechanical Adipose Filled with fat Found below the support to connective globules, they act as skin, around organs. tissue an insulator. internal organs Stratified Form layers of Found in the epidermis epithelium epithelial of the skin, lining of the cells, mouth cavity and Muscle Tissue composed of esophagus. Because of their elasticity and flexibility, it allows one or animals to move. They have elongated cells called different types muscle fibers of epithelial cells Types of Muscle Tissues Striated Cylindrical in shape and Found in Muscle contains many nucleus. limbs, Connective tissue Each muscle fiber has hands, - a network of cells that connects and binds different alternating dark and light- main body tissues and organs of the body. colored bands called trunk, face striations. Help animals and neck. Connective Tissues move limbs and lift objects. Blood A fluid connective Found in blood It is a voluntary muscle. tissue composed of vessels. Smooth Has the shape of a spindle, Alimentary plasma, RBC, WBC Muscle and has one nucleus, has no canal, eye, & platelets. It flows striations. It moves food urinary through blood down the esophagus, bladder vessels carrying stomach, and through the and oxygen, nutrients, intestines. It is an involuntary bronchi of hormones, & muscle. the lungs. antibodies to Cardiac Branched muscle, cylindrical Heart different parts of the Muscle in shape with a single body. nucleus. Its contraction and Bone Bone cells are Found in bones. relaxation produce embedded in a heartbeats which force matrix composed of blood to circulate. It is an calcium & involuntary muscle.  Nervous Tissue Some Specialize Cells in Animals Sperm cells They are specialized for human The nervous tissue receives, processes, and transmits reproduction. The prominent parts of information from one par of the body to another. The two the sperm cell are the nucleus and the cells that make up the nervous tissue are the neurons tail. The tail allows the sperm cell to be and glial cells, also called neuroglia. Neurons join end to mobile and vigorous in swimming end to form a nerve fiber. Nervous tissues form the brain, through the vaginal canal. Its prominent spinal cord, and nerves. head allows it to penetrate the female egg cell. Ovum (Egg They are the female reproductive cells. The combination of nerves and muscles allow organisms Cells) The prominent part of an egg cell is its to act in response to stimuli. main body which is significantly larger than the sperm cells. An egg cell is Cells that Make Up the Nerve Tissue covered by corona radiata which are Neuron A nerve cell which is the building block of layers of follicle cells that supply vital the nervous system. It specializes in proteins to the egg cell. receiving, processing, and transmitting Red blood RBC transport oxygen to body tissues & information throughout the body. cells carries carbon dioxide back to the Glial cell Surrounds neurons and holds them in lungs. A red blood cells has a biconcave (neuroglia) place, supplies nutrients and oxygen to shape which gives it a larger surface neurons, insulates one neuron from area for gas exchange. This shape also another, destroys pathogens and dead adds to its flexibility, enabling the blood neurons. to pass through narrow capillary vessels White blood WBCs identify and destroy pathogens. cells They have granules which engulf and SPECIALIZE CELLS (leukocytes) digest bacteria. They have a long and narrow shape to allow them to pass Some Specialize Cells in Plants through narrow gaps. Guard Found in leaves, they surround and control Microvilli Microvilli are finger like projections in cells the opening and closure of the stoma in (singular. the intestinal wall which increase the response to changes in temperature and microvillus) intestines surface area, and thus, scarcity of water. Guard cells come in increase the intestine's absorptive pairs. capacity. Root Part of the dermal tissue of roots. They add Ciliated Ciliated epithelial cells have hair-like Hairs to the surface area of roots and increase epithelial projections that allow the cell to push their absorptive capacity. tissue mucus forward into the nasal tract to Tracheids Elongated cells in the xylem of vascular clear the passage way of the respiratory plants that aid in transporting water and tract nutrients from the root's top other parts of the plant. Palisade Cells designed for photosynthesis; they cells contain a structure called chloroplast (leaf which contains green pigments called cells) chlorophyll. Chlorophyll absorbs light energy from the sun.  CELL DIVISION Prophase The process that cells use to make copies of The nucleus disappears. themselves. The chromatin condenses to form chromosomes Two identical copies of each chromosome (sister Single celled organisms can use it to reproduce. chromatids) are attached to centromere) Cell Cycle Centromere moves to opposite poles. Formation of mitotic spindle The Cell Cycle is an ordered series of events involving cell growth and cell division that produces to new Metaphase daughter cells. Chromosomes lined up at the equatorial plate. Cells on the path to cell division proceed through a series Nuclear envelope completely dissolves. of precisely timed and carefully regulated stages of growth, DNA replication, and division that produces two Anaphase identical cells. Replicated chromosome separates. Cell Division: Reasons Daughter chromatids move to opposite poles. Chromosomes are very condensed at the late Grow, Repair, Replace, Reproduce anaphase. INTERPHASE Telophase The phase in which the cell prepares itself for cell The last phase of mitosis. division. Two daughter nuclei are formed. Divided into subphases: Spindle Fibers disappear First Gap Phase Synthesis Phase Second Gap Nuclear envelope forms around the chromosomes. (G1 Phase) (S Phase) Phase (G2 Phase) CYTOKINESIS Division of Cytoplasm Divides the cell into two daughter cells which are INTERPHASE: G1 Phase identical to the parent cell Cells undergo a period of growth at a very fast rate !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! INTERPHASE: G2 Phase Cell division involves a series of steps that produce two genetically identical daughter cells. Cells grows again and completes preparations for cell division. Two divisions occur during cell division: Nuclear division (Mitosis) and cytoplasmic division (cytokinesis). MITOSIS (M PHASE) During interphase: cell grow, and genetic material is A type of cell division in which a daughter cell has replicated. the same number of chromosomes as the parent cells, also defined as the equational division. During Mitosis, P-M-A-T It occurs in body cells, for growth and replace worn MEIOSIS out cells A phase where nuclear division occurs known as A type of cell division in which a daughter cell has half karyokineses. the number of chromosomes of the parent cell; also defined as the reductional division. It is involved in the formation of sex cells or gametes (sperm and egg cell). The number of chromosomes in a gamete is called the haploid chromosome number, or n; the number of chromosomes in all other cells having a nucleus is twice Diakinesis (Recondensation) - chromosomes are fully the haploid number and is called the diploid number, or condensed and nuclear membrane disappears. 2n Metaphase I A human cell which consists of 46 chromosomes will Homologous chromosomes are attached to the spindle undergo meiosis and produce gametes that have 23 fibers and line up along the equatorial plate. chromosomes Anaphase I Human offspring (zygote which is diploid, 2n = 46 ) is a combination of genetic information from parents, 23 Homologous chromosomes separate and move toward chromosomes (haploid, n = 23 ) from the father (sperm the opposite poles; one member of the homologous pair cell) and 23 chromosomes (haploid, n = 23 ) from the will be distributed in each new cell mother (egg cell) Telophase I Homologous chromosomes Nuclear membrane starts to form around each nucleus; -paired chromosomes which is similar in shape, size, and chromosomes in the two nuclei are not the same gene arrangement has two nuclear divisions that because each of the daughter cells contains one produce four haploid cells member of the homologous chromosome pair and has half the number of chromosomes of the parent cell - For reproduction of species. MEIOSIS II: Second Division MEIOSIS 1: First Division Like mitosis but genetically unidentical; results in the It reduces the number of chromosomes from diploid formation of four haploid cells from the two haploid cells (2n) to haploid (n). produced in Meiosis I. Meiosis 1 has this following phases: No replication of chromosomes. Prophase I, Metaphase I, Anaphase I, Telophase I Prophase II Prophase I It signals the start of the second meiotic division; The longest subphase of meiosis has five distinct nuclear membrane disappears, and spindle fibers substages. gradually form. Leptotene (Condensation)- chromosomes duplicate, Metaphase II condense and coil. Zygotene (Pairing)- chromosomes start to [air up with Chromatids pinned together by centromeres with two other chromosomes that carry the same set of genes kinetochores are attached to the spindle fibers from in the process called synapsis; the thin space centrosomes at opposite poles; chromosomes aligned at between the two chromosomes is called the equatorial plate. synaptonemal complex; paired chromosomes are Centromere- holds two chromatids in a chromosome called as homologous chromosomes and the whole structure is called tetrad or bivalent because each Kinetochore - sister disc shaped protein complex found pair is made up of four chromatids. in centromere region of the chromosome where spindle fibers are attached Pachytene (Recombination)- genetic information is exchanged between chromosome pairs in the process of Anaphase II crossing over which results to the formation of chiasma Sister chromatids of each chromosome separate and (plural: chiasmata) that serves as attachment of two move to opposite poles; nuclear membrane starts to non- sister chromatids. form around the chromatids Diplotene (Coiling) - synapsis ends and the Telophase II synaptonemal complex disappears; homologous pairs of chromosomes remain attached at chiasmata. Final stage of meiosis; second division of cytoplasm; four haploid cells are produced.  Comparison between Meiosis I and Meiosis II MITOSIS: IMPORTANCE AND APPLICATIONS Meiosis I Stages Meiosis II Growth and development of an organism by Synapsis and Prophase Synapsis and producing new cells. crossing over crossing over do Heals and repairs worn out cells and replaces the occur. not occur. old and damaged cells with new cells. Side by side Metaphase Random alignment Responsible for asexual reproduction where the alignment of of chromosomes offspring is a clone to its parent organism. homologous at the equatorial Hereditary traits are equally distributed to the chromosomes at plane. the equatorial daughter cells. plane. Genetic information from parent organism is Migration of Anaphase Migration of sister preserved or remain unchanged from one homologous chromatids generation to another generation. chromosomes towards each towards each spindle fiber. MEIOSIS: IMPORTANCE AND APPLICATIONS spindle pole. Production of sex cells or gametes, sperm cell for Two haploid Telophase Four haploid male and egg cell for female. daughter cells are daughter cells are Responsible for sexual reproduction of organisms formed. formed. which carries genetic information from the father and mother. Comparison between Mitosis and Meiosis Results in the variation of genetic traits among offspring. Mitosis Meiosis Maintain the number of chromosomes among Once DNA replication Once organisms in each new generation. To repair Objective To produce damaged or gametes Basis for evolution because of the variations replace dead produced. cells Disorders and Diseases that result from the No Promote Yes malfunction of the cell during the cell cycle. variation One Number of Two Meiotic Cell Division Malfunction division No Synapsis Yes SEX CHROMOSOMES No Chromosomal Yes The pair of chromosomes that have a role in the sex of crossing over an individual. Randomly Homologous Side by side In females, this pair was always two rod shaped chromosome during alignment metaphase 1 chromosomes of identical length, while the male had during one rod-shaped chromosomes and a smaller hook- metaphase shaped chromosome Yes Division of Occurs only The rod-shaped chromosomes are called X centromeres during chromosomes while the hook-shaped is called Y centromeres chromosome. anaphase II Same with the Chromosome Half the Factors associated with chromosomal error chromosome of number per chromosome 1. Errors in Meiosis the parent cell daughter cell number of the parent cell 2. Environment two Number of Four daughter cells 3. Age of mother  1. Errors in meiosis Disorders associated with chromosomal abnormality - In meiosis, the expected number of chromosome to be 1. Turner Syndrome (45, XO) produced should be 23 for the sex cells 2. Down Syndrome (Trisomy 21) -If meiosis does not occur properly, the sperm or egg cell 3. Klinefelter Syndrome (47, XXY) - may end up with more or less than the required number 4. Trisomy X (47, XXX) of chromosome Turner syndrome (45, XO) -The process where the chromosomes or chromatid fail to separate during meiosis is called 'Nondisjunction" - Chromosomal monosomy disorder, seen in female individuals Nondisjunction - Affected females have small and underdeveloped -Nondisjunction can occur either in Meiosis I or Meiosis II ovaries, uterus, and oviducts Meiosis I Nondisjunction - Loses the ability of normal ovarian function -Happens when homologous pairs fail to separate - They do not experience puberty at normal age -A homologous pair migrates to only one side of the cell - Characteristics: short, broad chest, webbed neck and instead of separating. puffiness or swelling of hands and feet -This leaves the one resulting cell with an extra - They also have normal intelligence and can live fairly chromosome, while the other cell with no chromosome normal lives Nondisjunction in Meiosis II - Some can even give birth using invitro fertilization from - involves normal separation of chromosomes in Meiosis donor eggs I, but sister chromatids fail to separate during anaphase Down syndrome (trisomy 21) II - The most common disorder of trisomy is Down Result of genetic mutation Syndrome wherein, the 21st chromosome had three 1. TRISOMY instead of two During fertilization, any defective sperm or egg and its - It occurs in 1 out of 800 newborns fusion to a partner's sex cell can produce an embryo - Most cases of Down Syndrome is not due to inheritance having an extra chromosome but, on random mistakes during the formation of 2. MONOSOMY reproductive cells of one of the parents. If it results in missing chromosome - Most abnormalities occur in egg cells with occasional occurrences in sperm cells. -Most pregnancies associated with Trisomy or Monosomy, may lead to full term birth but with babies Characteristics having health problems. - Short stature, round head, flat face, slanting eyes, -Some pregnancies may lead to miscarriage or stubby (short & thick) fingers, wide gap between the 1st stillbirth/abortion due to this chromosomal abnormality. and 2nd toes, short neck, short arms, and short legs -If a woman's immature eggs are exposed to drugs, - They have muscle tone and loose joints that improve toxins, or radiation that can induce mutation, the chance with age of producing unhealthy egg cell is high. - They are born with number of birth defects in the heart, intestine or breathing. - Delayed mental development and behavioral problems - Gradual decline in mental abilities around the age of 50 are also experienced Klinefelter syndrome (47, XXY) -Chromosomal abnormality affecting the physical and cognitive development of males. -Those affected have underdeveloped prostate gland and testes, thus, there is shortage of testosterone production. This leads to delayed or incomplete puberty, lack of facial and body hair, breast enlargement, and unusual small penis. -Affected males have big hands and feet, and usually long arms and legs -They may have delayed speech and language development, and learning disabilities -Some variants of Klinefelter have more than one extra chromosome in each cell such as in 48, XXXXY or - 49,XXXXY that are associated with severe form of abnormality Trisomy x (47,xxx) -Affects 1 in 1000 females -Affected individuals usually have mild symptoms or none at all -If symptoms are more pronounced, these may include development delays and language-based learning disabilities -In addition to meiosis, the age of mother can also add up to the equation. The older the woman is, during pregnancy, the older the age of her eggs because she was born with all the eggs she will ever have. -A woman of 45 years during pregnancy has a 45-year-old egg as well. -Errors in meiosis have a higher risk due to the aging process. -Incorrect number of chromosomes were also found by fertility doctors to be connected with aging eggs