General information about biology. Good reviewer for an exam covering general knowledge...
Biology Hypertonic environment – cell has a lower concentration of solutes; higher water potential than surrounding extracellular fluid Osmosis – diffusion of water An erythrocyte placed in a hypertonic solution would crenate, become distorted in shape. Hypotonic environment – cell has a higher concentration of solutes than the solution outside the cell which causes the cell to well Isotonic environment – cell has equal concentration with the solution outside the cell Membrane proteins – act as enzymes and receptor sites; function for chemical transport, intercellular communication, cell-to-cell recognition, and attachment to the cytoskeleton and extracellular matrix Formation and transport of vesicles: 1. Secretory proteins are assembled by the ribosomes on the rough ER which, in turn, extrudes them across the ER into its channels 2. Enzymes embedded the smooth ER may chemically modify some of the proteins 3. Proteins pass through more channels to the Golgi body 4. Proteins are encapsulated in vesicles by the pinching together of membranes of the Golgi body 5. Vesicles then pass through the cytoplasm, fuse with the interior surface of the plasma membrane and release their contents to the exterior. Lymphocytes – subclass of white blood cells that are divided into two types: B-lymphoctes and Tlymphocytes B-lymphocytes – secretes antibodies for humoral immune response, where it binds to the antigen and eventually destroys it. Non-specific defenses – surface barriers and defensive chemical cells (which are made in the body), cellular and chemical defenses such as neutrophils and interferons (that affect its actions one pathogens invade the tissues)
T-lymphocytes – processed in the thymus that initiates the attack on foreign bodies Cell-mediated response – accomplished by Tlymphocytes; involves attacking the virally infected cells and cancer cells Mutation – alteration of the form of a particular gene or chromosome that results in a new trait to be inherited; can occur in chromosome structure or chromosome number Frameshift mutation – the whole frame of the genetic sequence is changed Insertion of “I” THE CAT AND DOG RUN THE CAI TAN DDO GRU N Point mutation – only one nucleotide is modified to become another nucleotide THE CAT AND THE DOG RUN THE RAT AND THE DOG RUN Three type of point mutation: a) Silent mutation – causes no change in the activity of the protein b) Missense mutation – results in a change of the activity of the protein c) Nonsense mutation – results to a protein shorter than usual; non-functional Population density – population size per unit area/volume; two kinds of factors: dependent and independent Density-dependent factor – intensifies as the population increases in size Density-independent factor – not related to population size Homeostasis – ability to maintain a stable internal environment Development – transform from an immature to a mature functional form Adaptation – structural modification in organisms that enables them to adjust to a changing environment Growth – irreversible increase in the number, size and/or number of cells Procambium – derivative meristem that develops into the vascular tissue Protoderm - develops into surface or dermal tissues
Ground meristems – produces fundamental/ground tissues (parenchyma, collenchymas and schlerenchyma) Cork cambium – produces the protective layer of the bark, cork Kingdom - highest level of classification of living things Five kingdoms: Monera Protista – water mold Fungi – yeast, mushroom, bread mold Plantae Animalia – shark and milkfish (Kingdom Animalia, Phylum Chordata), turtle and snake (Kingdom Animalia, Phylum Chordata, Class Reptilia) D’ Kings Play Chess On Fat Green Stools Vitiligo – disorder in which melanocytes, cells which produce melanin pigment, are unable to function; results to white patches on the skin Albinism – chromosomal mutation that results in the cessation of melanin production or a considerable decline in the amount of melanin Dihybrid cross – cross that involves two traits Mendelian Laws of Inheritance – traits will segregate and assort independently Genotype – genetic makeup or genes of an individual Allele – one of the alternative pair of genes; may be in two forms: dominant and recessive Dominant – mast the effect of the recessive allele; represented by a capital letter Recessive – allele that is masked by the dominant allele; represented by a small letter Phenotype – shows the physical appearance of an individual dictated by the genotype Antigen - any substance foreign to a body that evoke an immune response Antibody – any of a large number of proteins of high molecular weight that are produced normally by specialized B cells after stimulation by an antigen; act specifically against the antigen in an immune response Blood type A – has antigen A and antibody against B Blood type B – has antigen B and antibody against A
Blood type AB – “universal recipient” because it can receive all blood types; has antigen A and B and has no antibody Blood type O – “universal donor” because it can donate to all blood types, has no antigen but has antibody against A and B Prokaryotes – do not have nuclear membrane, has its DNA exposed to the cytoplasmic environment; Kingdom Monera (bacteria, reproduces through binary fission, and blue-green algae) Developmental biology – study of the development of animals; processes involved in the transformation of fertilized egg to a more complexed individual Gametogenesis (production of gametes) –> Fertilization –> Cleavage –> Gastrulation (formation of germ layers) –> Organogenesis (development into different tissues and organs) –> Growth and histological differentiation Biome – ecological community dominated with distinctive plants and animals Tropical rainforests – found in areas near the equator where rainfall is abundant and the dry season lasts for no more than a few months; richest biome in terms of number of species Taiga – heavy snowfall; conifer forests Desert – sandy and receive less rainfall Savannah – grassland regional and seasonal rain Tundra – cold with frozen undersoil Estuary – part of a river (freshwater) joined with the sea (saltwater) Diplohaplontic life cycle – alternation of generation (life cycle of plants) Dominant diploid sporophyte – ferns, pine trees and common weeds Dominant haploid gametophyte – mosses Haploid gametophyte – part of the plant life cycle having haploid nuclei; gives rise to sex cells that produce a diploid sporophyte after fusing. Meiosis – cell division responsible for the formation of gametes or sex cells which results to four cells with half the ploidy number of the mother cell; divided into two stages: Meiosis I and Meiosis II where
during Telophase I, the number of chromosomes will be reduced to half Mitosis – somatic cell divides to form to identical diploid daughter cells a) Prophase - condensation/coiling of chromosomes b) Metaphase – alignment of chromosomes along the equatorial plate c) Anaphase – separation of sister chromatids d) Telophase – mitotic apparatus formed during prophase is disassembled Sinoatrial node – found at the right atrium; send impulses through the atria resulting in atrial systole; considered as the pacemaker of the heart Atrioventricular node – the heart’s electrical system activated by the impulse caused by the SA node; passes impulses down to the bundle of His resulting in the ventricular systole Cardiac cycle: a) Deoxygenated blood travels through the vena cava b) The blood will flow through the right atrium, right ventricle and lungs and becomes oxygenated c) It will then travel through the left atrium, left ventricle, aorta and to all the cells in the body The sound of pumping of the heart is caused by the valves. Order from the outside of a woody eudicot (true cotyledon) stem: cortex -> primary phloem -> secondary phloem -> vascular cambium -> secondary xylem -> primary xylem -> pith Centriole – can only be found in animal cells Cell wall – exclusive to plant cells Ethylene – plant hormone that promotes ripening; carbon dioxide will inhibit the action of ethylene by preventing ethylene from accumulation Organogenesis - formation of organs Differentiation – cells choose to become a particular type of cell that will function for a specific organ Differentiated cell – utilizes a particular set of proteins to perform its function; assume a specific
shape to function effectively to the tissue it belongs; metabolically active to perform its function for a specific organ; examples are muscle cells, nerve cells and red blood cells Cell cycle – divided into two parts: interphase and M-phase (dividing phase) Interphase: a) Gap 1 (G1) phase – has a specific checkpoint that decides whether or not to begin replication; enters G0 phase, if the condition is not ideal, where they are maintained for prolonged periods in a non-dividing state; growth and production of substances needed inside and outside the cell b) Synthesis (S) phase - DNA replication and formation of proteins in DNA c) Gap 2 (G2) phase – organization of specialized structures required for chromosome movement and replication Scientific name – made up of two names: genus (generic name) and species (specific epithet) Dichlorophenlytrichloroethane (DDT) and Polychlorinated biphenols (PCBs) – well-known pesticides that are harmful and becomes more concentrated in the successive trophic levels of the a food web Traffic of molecules across the membrane: a) Small polar uncharged molecules (water and carbon dioxide) will easily pass b) Hydrophobic molecules (hydrocarbons and oxygen) can cross with ease because they can dissolve in the lipid bilayer c) Large polar uncharged molecules (proteins and sugars) will not pass d) Ions (H+, Na+, Cl-, K+) will not readily pass and will need transport proteins or channels Sodium-potassium pump – one of the important means of transport of molecules a) An active transport process that uses up energy in the form of ATP b) Responsible for establishing the charge difference maintaining the nerve cell membrane resisting potential c) Works through a series of conformation changes in the transmembrane protein
Progesterone – substance that prepares the endometrium in the uterus for implantation of fertilized egg; inhibits the follicle-stimulating hormone thus preparing the uterus for pregnancy; secreted by the corpus luteum Corpus luteum – comes from a ruptured follicle that is repaired and turned yellowish Infundibulum – funnel-shaped distal end of each uterine tube (fallopian tube) Graafian follicle – mature ovarian follicle Seminiferous tubule – site of spermatogenesis Charles Darwin’s Natural Selection – as the conditions of nature change, individuals that are fittest and can adapt will survive and evolve Genetic drift – chance events result in a change of allele frequencies Migration – populations exchange members to converge toward one another Theory of Uses and Disuse – as the organism continues to use a certain part of its body, it enlarges or elongates Cell cleavage – increase in cell number and in the amount of genetic material; formation of blastula Development of neural crest – happens after the formation of the three germ layers; derived from the ectoderm Cellular respiration – enables cells to harvest the energy stored in food; a catabolic process in which organic compounds breakdown into simpler substances through the transfer of electrons during redox reactions; an oxidation-reduction process; occurs in the mitochondria of cells Anabolic processes – consume energy to build complex molecules from simpler ones Unicellular organism – made up of only one cell; undergoes reproduction when its cell divides Multicellular organism – undergoes growth when its cell divides Development – transformation from an immature to a mature functional form Turner syndrome - a disorder caused by missing or incomplete X chromosomes (XO); individual shows
the external physical appearance of a female and does not develop secondary sex characteristics; shows the appearance of only one X chromosome due to non-disjunction (sex chromosomes fail to separate during the formation of the egg) Aneuploidy – a type of numerical chromosomal abnormality that refers to an extra or missing chromosome such as in Trisomy 21 (Down Syndrome) or Monosomy (Turner Syndrome) Polyploidy – another type of numerical chromosomal abnormality that refers to an addition of an entire complement of haploid chromosomes such as triploidy in which three haploids sets occur like XXX, XXY or XYY. These abnormalities may involve either autosomes or sex chromosomes. Some common trisomies are: a) Trisomy 13 (Patau syndrome) – gross multiple structural defects involving polydactyly (having more than the normal number of fingers and toes) and cleft lip or palate b) Trisomy 18 (Edwards syndrome) – severe psychomotor and growth retardation c) Trisomy 21 (Down syndrome) – most common viable autosomal trisomy; depressed nasal bridge, shortened extremities and mental retardation Producers – placed on the base of the energy pyramid because they have the large quantity of energy available by being the organism that can convert light energy into chemical energy Pituitary gland – divided into anterior and posterior pituitary Anterior pituitary (adenohypophysis) – produces growth hormones, luteinizing hormone, thyroidstimulating hormone, adrenocorticotropic hormone and follicle-stimulating hormone Growth hormone – targets body cells and stimulates growth and repair Adrenocorticotropic hormone – targets the cortex of adrenal glands; helps in metabolism regulation and body stress release Prolactin – stimulates milk production and secretion Posterior pituitary gland (neurohypophysis) – produces oxytocin and the antidiuretic hormones
Antidiuretic hormone (vasopressin) – targets the kidneys; increases reabsorption of water during urine production which results to less urine Oxytocin – causing the contraction of the uterus and ejection of milk
DNA structure – double strand twisted with one another to form a spiral staircase; complementary bases are A-T (Adenine and Thymine) and G-C (Guanine and Cytosine) Extraembryonic membranes – developed by some vertebrates because of the delicate condition of the eggs of animals (i.e. yolk sac, chorion, allantois and amnion, which contains the amniotic fluid) Amniotic fluid – serves as a cushion sac around the embryo against physical trauma; bathes the embryo serving as a barrier of the embryo against mechanical injury Skeletal muscle – elongated, multinucleated, striated, nucleus found at the periphery of the cell (i.e. muscles of the arm) Smooth muscles – spindle-shaped, uninucleated, non-striated, nucleus found at the center (i.e. stomach, blood vessels) Cardiac muscles – striated, uninucleated, nucleus found at the enter of the cell, presence of intercalated disks (i.e. heart) Myofibrils – rod-like bundles in each muscle fiber containing a thin protein, actin, and a thicker protein, myosin
Recombinant DNA – one of the successful applications of genetics in our society; reason behind mass production of vaccines, hormones, and others (i.e. insulin production) Insulin production – insulin gene from human DNA is cut with the use of restriction enzyme, combined in a plasmid (secondary DNA) and inserted into Escherichia coli Primary ecological succession: 1. Begins in a lifeless area where soil has not yet formed such as a new volcanic island or a rubble left behind by a retreating glacier 2. In glaciers (like in Glacier Bay, Alaska), the barren ground is occupied by mosses and lichens then by dwarf willows 3. After approximately 50 years, alders form dense stands 4. These eventually give way to Sitka spruce, joined later by hemlock (spruce-hemlock forest) recognize today as taiga Oogenesis – meiosis that occurs in the ovary of female organisms During the process of Meiosis I and II, the primary oogonium divides the cytoplasm unevenly (one polar body produce from Meiosis I, another polar body produced from Meiosis II), producing a polar body, thus only one active cell is formed.
Phylum Arthropoda – animals characterized by joined legs; five classes namely: Insecta, Crustacea, Arachnida, Chilopoda, and Diplopoda Class Crustacea – arthropods having two pairs of antennae and various pairs of legs (i.e. crabs, lobsters, shrimps) Class Arachnida – scorpions Class Chilopoda – centipedes Class Insecta – grasshoppers Macronutrients – elements needed by the plants in relatively large amounts (i.e. oxygen, carbon, hydrogen, nitrogen, potassium, calcium, magnesium, phosphorus, and sulfur.
Autonomic nervous system – section of the nervous system which controls involuntary functions; has two divisions: sympathetic and parasympathetic
Sympathetic division – prepares the body for emergency responses; has effects such as the widening of the trachea, increasing of the heart rate and liver stimulation for glucose release Parasympathetic division – rests the body and produces calm responses, has effects such as the increasing of stomach contractions to promote digestion, narrowing of the pupils of the eyes and the constriction of the trachea Neuron – functional unit of the nervous system Parts of the neuron: Dendrite – receives the message Axon – send the message to another dendrite Soma – cell body where nucleus is located Germinal layers - includes the ectoderm, mesoderm and endoderm; rudiments from which the different organs of the body are derived Ectoderm – outer germinal layer; gives rise to the skin epidermis and organs of the nervous system Mesoderm – origin of the skeletal muscles and blood vascular system; divided into two layers: dorsal mesoderm and lateral mesoderm Dorsal mesoderm – three regions: myotome (form the muscles), sceleretome (form the vertebra and other bones, except facial bone) and dermatome (form the dermis of the skin of the lower back) Endoderm – develops the digestive tracts and glands Hemophilia – an X-linked recessive genetic disorder in which blood fails to clot properly due to gene mutations; individual affected may experience easy bruising and sudden bleeding Symbiosis – interaction between two different organisms Mutualism – both the host and the symbiont benefit from each other Commensalism – relationship in which the symbiont benefits but the host is neither helped nor harmed Parasitism – the symbiont benefits at the expense of the host by either living within the host (endoparasite) or outside the host (ectoparasite) Source: MSA National Medical Admission Test (NMAT) Practice Test I in Biology