Reviewer-in-General-Biology-I.pdf

REVIEWER IN GENERAL BIOLOGY 1 Biology ROBERT HOOKE -study of living organisms and their interaction with one A British scientist another in their environments. In 1665 Hooke mad...

REVIEWER IN GENERAL BIOLOGY 1 Biology ROBERT HOOKE -study of living organisms and their interaction with one A British scientist another in their environments. In 1665 Hooke made an important discovery under a compound optical microscope. Branches of Biology When he looked at a thin slice of cork under his Anatomy- study the forms and structure of the body. microscope, he saw that the cork was made-up Botany- study the plants. of many tiny units’ room like structure, he saw Cytology- study the cells. tiny little shapes that looked like little rooms with Biochemistry- study of chemical substances and process in walls around each of them. He named them living organisms. “cellulae” or simply “Cell”. Ecology- Relationship of living organisms to their environment. “CELLULAE” Latin word means "little rooms” BRANCHES OF BIOLOGY FIRST DISCOVERY OF CELLS Zoology- Study of animals. Genetics- study of heredity and variation. Microbiology- the study of microorganisms. Matthias Jakob Schleiden Taxonomy- naming and classifying organisms. 1838 Paleontology- study of fossils. German botanist and was the first to state that Histology- the study of tissues. cells are the building blocks of all plants and that Physiology- concerned with functions of tissues, organs, an embryonic plant arose from one single cell. and systems. Phycology- study of algae Theodor Schwann Mycology- study of fungi States that cells are the fundamental units of Bacteriology- Study of bacteria. animals too. These statements ended the notion Herpetology- Reptiles and amphibians. that plants, and animals have fundamental differences in structure. CELL Proposed the unified cell theory, which states THE BUILDING BLOCK OF OUR BODY OR LIFE. that all living things are composed of one or more cells, that the cell is the basic unit of life, PERSON’S BEHIND THE CELL THEORY and that new cell arise from existing cells. Zacharias Janssen and Hans Lippershey contributor on the discovery of the cell. known Rudolf Virchow for the invention of optical microscope. ❑ German physiologist stated in German Omnis Optical Microscope cellula e cellula, which means that new cells come -1590’S from already existing cells. C-ells ANTON VAN LEEWENHOEK (1964) T-issue The first to observe live cells. O-rgan Invented microscope with improved lenses that O-rgan System could magnify objects from 270-300 fold. O-rganisms Observed the movements of protista (a type of a single-celled organism) and sperm, which Prokaryotic vs. Eukaryotic Cells collectively termed “animalcules.” ❑ Prokaryotic cells were here first and for billions Microscopes with improved lenses. of years were the only form of life on Earth. All prokaryotic organisms are unicellular. REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT  ❑ Eukaryotic cells appeared on earth long after ❑ Eukaryotes have a complex internal structure and prokaryotic cell but they are much more it is larger than prokaryotes. The size off a advanced. Eukaryotic organisms unlike eukaryotic cell ranges from 10-100 µm. prokaryotic can be unicellular or multicellular. ❑ Eukaryotic cells have a membrane-bound nucleus. Characteristics of Prokaryotes ❑ Numerous membrane-bound organelles such as ❑ Prokaryotes are the simplest type of cell. the endoplasmic reticulum, Golgi apparatus, ❑ Oldest type of cell appeared about four billion chloroplast, mitochondria, and others. years ago. ❑ Several rod-shaped chromosomes. ❑ Prokaryotes are the largest group of organisms. ❑ Prokaryotes unicellular organisms that are found Parts of Eukaryotic Cells in all environments. THE NUCLEUS ❑ Prokaryotes do not have a nuclear membrane. ❑ The nucleus is the most prominent organelle in a Their circular shaped genetic material dispersed cell. It houses the cell’s DNA and directs the throughout cytoplasm. Prokaryotes do not have synthesis of ribosomes and proteins. membrane-bound organelles. They have a simple NUCLEAR ENVELOPE internal structure. Prokaryotic DNA is found in a ❑ It is a double membrane structure that central part of the cell which is the nucleoid. constitutes the outermost portion of the nucleus. ❑ At 0.1 to 5.0 µm in diameter, prokaryotic cells Both of the inner and outer membranes of the are significantly smaller than eukaryotic cells. nuclear envelope are phospholipid bilayers. The nuclear envelope is punctuated with pores that Parts of Prokaryotic Cell control the passage of ions, molecules, and RNA CELL WALL between the nucleoplasm and cytoplasm. ❑ The cell wall acts as an extra layer of protection, NUCLEOPLASM helps the cell maintain its shape, and prevents ❑ The nucleoplasm is the semi- solid fluid inside the dehydration. nucleus, where we find the chromatin and the CAPSULE nucleolus. ❑ It enables the cell to attach to surfaces in its CHROMATIN AND CHROMOSOMES environment. ❑ These are the unwound protein-chromosome FLAGELLA complexes. Chromatin describes the material that ❑ It is used for locomotion. makes up the chromosomes both when condensed PILI and decondensed. ❑ Are used to exchange genetic material during a NUCLEOLUS type of reproduction called conjugation. ❑ It is the dark straining area within the nucleus FIMBRAE that aggregates the ribosomal RNA with ❑ used by bacteria to attach to a host cell. associated proteins to assemble the ribosomal subunits that are transported out through the pores in the nuclear envelope to the cytoplasm. Characteristics of Eukaryotes RIBOSOMES ❑ Eukaryotic cells appeared approximately one ❑ Are the cellular organelles responsible for protein billion years ago. synthesis. They are attached to the cytoplasmic ❑ Eukaryotes are generally more advanced than side of the plasma membrane or the cytoplasmic prokaryotes. side of the endoplasmic reticulum and the outer ❑ Nuclear membrane surrounds linear genetic membrane of the nuclear envelope. They receive material (DNA). their “orders” for protein synthesis from the ❑ Unlike prokaryotes, eukaryotes have several nucleus where the DNA is transcribed into different parts. messenger RNA (mRNA). ❑ Prokaryote’s organelles have coverings known as MITOCHONDRIA membranes. ❑ Often called the “Powerhouses” or “energy factories” of a cell. They are responsible for making adenosine triphosphate (ATP), which is the cells main energy carrying molecule. REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT  Mitochondria are oval-shaped, double membrane 1. MICROFILAMENTS organelles that have their own ribosomes and They are the narrowest among all types of DNA. fibers. They function in cellular movement, have PEROXISOMES a diameter of about 7nm, and are made of two ❑ They are small round organelles enclosed by intertwined strands of globular protein called single membranes. They carry out oxidation actin. It is also called actin filaments. reactions that break down fatty acids and amino acids. They also detoxify many poisons that may 2. INTERMEDIATE FILAMENTS enter the body. Glyoxysomes are specialized It is made up of several strands of fibrous peroxisomes in plants that is responsible for proteins that wound together. These elements of converting stored fats into sugars. the cytoskeleton get their name from the fact VESICLES AND VACUOLES that their diameter is 8 to 10 nm between those ❑ Vesicles and vacuoles are membrane-bound sacs of microfilaments and microtubules. that function as storage and for transport. THE ENDOMEMBRANE SYSTEM 3. MICROTUBULES ❑ This system is a group of membranes and They are small hollow tubes. Its wall is made of organelles. They work together to be able to polymerized dimers of α-tubulin and β-tubulin modify, package, and transport lipids and two globular proteins with a diameter of about proteins. It includes nuclear envelope, lysosomes, 25 nm, microtubules are the widest components vesicles, endoplasmic reticulum, and Golgi of the cytoskeleton. They also help the cell resist apparatus. compression, provide a track along which vesicles ROUGH ER move through the cell, and pull replicated ❑ It is associated with ribosomes; makes excretory chromosomes to opposite ends of a dividing cell. and membrane proteins. This is the place where synthesize proteins undergo structural MULTICELLUAR ORGANISM- use cell division for modifications, such as folding or the acquisition growth and maintenance repair of cells and tissue. of side chains. SMOOTH ER UNICELLULAR ORGANISM- use cell division as ❑ Its function is synthesize carbohydrates, lipids, their method of reproduction. and steroid hormones; detoxification of medications and poisons; and storage of calcium CELL CYCLE- orderly sequence of events that ions. describes the stages of cell’s life from the division of GOLGI APPARATUS or GOLGI BODY a single parent cell to the production of two new ❑ This is the place in our cell wherein sorting, daughter cells. tagging, packaging, and distribution of lipids and proteins take place. The receiving part of the INTERPHASE Golgi called the cis face and the opposite side is -the cell undergoes normal growth processes while the trans face. also preparing for cell division. LYSOSOMES ❑ Their role is to be a digestive component and THREE STAGES OF INTERPHASE organelle recycling facility of animal cells, lysosomes are considered to be part of the G1 (FIRST GAP) endomembrane system. They also use their hydrolytic enzymes to destroy pathogens that first interphase in microscopic aspect, the cell is quite might enter the cell. active at the biochemical level accumulating the CYTOSKELETON building blocks of chromosomal DNA and associated ❑ It is the network of protein fibers in the cell. proteins as well as accumulating sufficient energy ❑ There are three types of fibers within the reserves to complete the task of replicating each cytoskeleton these are microfilaments, chromosome in the nucleus. intermediate filaments, and microtubules. S PHASE (SYNTHESIS OF DNA) REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT  in the s phase, DNA replication can proceed through “first phase” the mechanisms that result in the formation of chromosomes condense and become visible identical pairs of DNA molecules-sister chromatids- spindle fibers emerges from the centrosome that are firmly attached to the centromeric region. prophase nuclear envelope breaksdown the centrosomes is duplicated during the s phase. nuclelus disappears. s phase (synthesis of dna) the two centrosomes will PROMETAPHASE give rise to the mitotic spindle, the apparatus that orchestrates the movement of chromosomes during o “First change phase” mitosis. at the center of each animal cell, the o chromosomes continue to condense centrosomes of animal cells are associated with a pair o kinetochores appear at the centromeres of rod-like objects, the centrioles, which are at right o mitotic spindle microtubules attach to angles to each other. centrioles help organize cell kinetochores division. centrioles are not present in the centrosomes o centrosomes move toward opposite poles of other eukaryotic species, such as plants and most fungi. METAPHASE o “Change phase” G2 (second gap) o mitotic spindle is fully developed, centrosomes are at opposite poles of the cells. the cell replenishes its energy stores and synthesizes o chromosomes are lined up at the metaphase proteins necessary for chromosome manipulation some place. organelles are duplicated, and the cytoskeleton is o each sister chromatid is attached to a spindle dismantled to provide resources for the mitotic phase. fiber originating from opposite poles. there may be additional cell growth during g2 phase. ANAPHASE the final preparations for the mitotic phase must be o upward phase completed before the cell is able to enter the first o cohesion proteins binding the sister chromatids stage mitosis. together breakdown. o sister chromatids (now called chromosomes) are THE MITOTIC PHASE pulled toward opposite poles. multistep process during which duplicated o non-kinetochore spindle fibers lengthen, chromosomes are aligned, separated, and move to elongating the cell. opposite poles of the cell, and then are divided into two new identical daughter cells. TELOPHASE the mitotic phase. o “Distance phase” o chromosomes arrive at opposite poles begin to first portion of the mitotic phase is called decondense. karyokinesis, or nuclear division. o nuclear envelope material surrounds each set of chromosomes. the second portion of the mitotic phase, called cytokinesis, is the physical separation of the o the mitotic spindle breakdown. cytoplasmic components into the two daughter cells. CYTOKINESIS o animal cells: a cleavage furrow separates the MITOSIS daughter cells. also known as karyokinesis o plant cell: a cell plate separates the daughter divided into series of phases cells. -prophase -cytokinesis -prometaphase MEIOSIS -metaphase -anaphase o known as “reduction division” -telophase o produces gametes PROPHASE REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT  o sexual reproduction requires fertilization (the o the sister chromatids remain tightly bound union of two cells from two individual together at the centromere. organisms. o sexual reproduction includes nuclear division TELOPHASE I + CYTOKINESIS that reduces the number of chromosome sets. o the separated chromosomes arrive at opposite poles. o separation of the cytoplasmic components into HOMOLOGOUS CHROMOSOMES two daughter cells o matched pairs containing the same genes in identical locations along their length. MEIOSIS II INTERPHASE o in some species, cells enter a brief interphase, or interkinesis, before entering meiosis II. S PHASE o interkinesis lacks an s phase, so chromosomes chromosomes are duplicated during interphase. the are not duplicated. resulting sister chromatids are held together at the o the two cells produced in meiosis I go through centromere. the centrosomes are also duplicated. the events of meiosis ii in synchrony. MEIOSIS I PROPHASE II o if the chromosomes decondensed in telophase PROPHASE I I, they condensed again. o chromosomes condense and the nuclear o the centrosomes that were duplicated during envelope fragments. homologous chromosomes interkinesis move away from each other bind firmly together along their length, toward opposite pole, and new spindles are forming tetrad. formed. o chiasmata form between non-sister chromatids. PROMETAPHASE II o crossing over occurs at the chiasmata. spindle o the nuclear envelope disappears and the fibers emerge from the centriole. spindle fibers engage the individual kinetochores on the sister chromatids. PROMETAPHASE I METAPHASE II o homologous chromosomes are attached to o the sister chromatids are maximally condensed spindle microtubules at the fused kinetochore and aligned at the equator of the cell. shared by a sister chromatid. o chromosomes continue to condense and the ANAPHASE II nuclear envelope completely disappears. o the sister chromatids are pulled apart by the kinetochore microtubules and move toward METAPHASE 1 opposite pole. o homologous chromosomes randomly assemble TELOPHASE II + CYTOKINESIS at the metaphase plate where they have been o cleavage divide the two cells into four haploid maneuvered into place by the microtubules. cells. ANAPHASE I o the microtubules pull the linked chromosomes apart. REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT REVIEWER IN GENERAL BIOLOGY I Sir. Christopher A. Deteral Jr., LPT