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Nairaland Forum / Nairaland / General / Education / Nairaland Jamb Tutorial Centre {Biology Thread} (9807 Views)
2016 NAIRALAND JAMB TUTORIAL {the Physics Thread } / Nairaland Jamb Tutorial Centre. {NJTC} / Biology Thread (2) (3) (4)
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Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 9:34am On Dec 01, 2014 |
Dsd1pumpking:k. 09033976204 |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 6:12pm On Dec 01, 2014 |
Thanks microflux .. Am learning , God bless.. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 3:53am On Dec 02, 2014 |
Microflux:since he has already started, let him just continue. anyway I'm following |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 7:21am On Dec 02, 2014 |
Microflux:alright, I'm sorry about that |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 7:00pm On Dec 02, 2014 |
GOOD DAY CLASS GENECTIC TERMINOLOGIES THEY TERMS USED IN GENETICS. Allele An alternative form of a gene that occurs at the same locus on homologous chromosomes, e.g., A, B, and O genes are alleles. Amorph A silent gene that does not produce a detectable product (antigen), e.g., O genes in the ABO BGS. Aneuploidy Having an abnormal number of chromosomes, i.e., not an exact multiple of the haploid number. For example, Downs syndrome (three #21 chromosomes) or Klinefelter syndrome (XXY males). Anticodon A sequence of three bases in tRNA that is complementary to a codon in mRNA. Enables tRNA to sequence amino acids in the order specified by mRNA. Antithetical Alternative forms of the same antigen produced by allelic genes, e.g., K and k antigens in the Kell BGS or C and c antigens in the Rh BGS. Autosome A non-sex chromosome. Synonymous with somatic chromosomes (chromosome pairs 1-22). Balanced polymorphism An equilibrium of two or more alleles that has remained constant over long periods of time. Barr body The sex chromatin, the visible inactive X chromosome on the somatic cell nuclear membrane. Beneficial gene A gene that confirms a trait that is advantageous to survival and that increases in frequency, e.g., the Fy gene that produces the Fy(a-b-) phenotype which makes West Africans resistant to certain types of malarial parasites. Chimera An extremely rare person composed of cells derived from different zygotes. Blood group chimerism is shown by mixed field agglutination when antigen typing red cells. Chimerism can be caused by dizygotic twins exchanging hematopoietic stem cells in utero and continuing to form blood cells that are genetically different, or by dispermic chimerism in which two separate zygotes develop into one person. Chromosome Rod-shaped structures within the cell nucleus that carry genes encoded by DNA. Cis position Genes in the cis position are on the same chromosome of a pair of homologous chromosomes. Mainly relates to the Rh BGS, e.g., in the genotype CDe/cde, D and C genes are in the cis position. Cloned gene A recombinant DNA molecule with the gene of interest. (Also see recombinant DNA.) Co-dominant Genes are co-dominant if both alleles are expressed in the heterozygous state, e.g., K and k genes in the Kell BGS. Codon A sequence of three bases in DNA or RNA that codes for a single amino acid. Enables specific proteins to be made by specific genes. Consanguinity Having a common ancestor, i.e., being blood relatives. Mating between two first cousins, for example, can be termed a consanguineous mating and is indicated in a pedigree by a double bar between the two parents. Such mating can result in an increased frequency of offspring who are homozygous for a recessive autosomal trait possessed by both parents, e.g. cystic fibrosis or the amorphic type of Rh null. Crossing over The exchange of genetic material between members of a pair of homologous chromosomes. For example, if a mating between a male (MS/Ns) and a female (MS/MS) results in an offspring who is MS/Ms, the recombinant child has occurred due to crossing over in the father. Deletion An abnormality in which part of a chromosome (carrying genetic material) is lost. Deleted phenotype The condition in which antigens that are normally present are missing, e.g., the Rh null phenotype in the Rh BGS. Deleted phenotypes can be caused by inheritance of regulatory genes that do not allow functional (antigen- producing) genes to make their products. Diploid number of chromosomes The number of chromosomes found in somatic cells, which in humans is 46. Dizygotic twins Twins produced from two separate ova that are separately fertilized, i.e. fraternal twins. Only dizygotic twins can exhibit blood group chimerism (shown by mixed field agglutination when antigen typing red cells). DNA Deoxyribonucleic acid. Composed of nucleic acids, these molecules encode the genes that allow genetic information to be passed to offspring. DNA polymerases Enzymes that can synthesize new DNA strands using previously synthesized DNA |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 7:03pm On Dec 02, 2014 |
Gamete A reproductive sex cell (ovum or sperm) with the haploid number (23) of chromosomes that results from meiosis. Gene A segment of a DNA molecule that codes for the synthesis of a single polypeptide. Gene flow Changes in gene frequencies that occur over long periods of time due to migration in which different populations interbreed. An example is the transfer of genes between racial groups, e.g., the "white" genes of the Duffy blood group system (Fya Fyb) have an increased frequency in U.S. blacks compared to African blacks. Gene interaction The situation in which genes inherited at different loci interact to produce red cell phenotypes, e.g., Le le genes interact with Hh and Se se genes to produce the various Lewis red cell phenotypes. Genome Term used to denote the entire DNA sequence (gene content) of a gamete, person, population, or species. Genotype All of the alleles present at the locus (or closely linked loci) of a blood group system, indicating chromosomal alignment if appropriate, e.g., AO in the ABO BGS, CDe/cde in the Rh BGS, or MS/Ns in the MNSs BGS. Genotypes are indicated by superscripts, underlining, or italics. Haploid number of chromosomes The number of chromosomes found in sex cells, which in humans is 23. Hardy-Weinberg law A law developed in 1908 independently by George Hardy (an English mathematician) and Wilhelm Weinberg (a German physician) that is the basis for calculations used in population genetics. The law is described by the formula p2 + 2pg + q2 = 100%, where p is the frequency of one allele, q is the frequency of the other, p2 and q2 are the homozygous frequencies, and 2pg is the heterozygous frequency. The formula allows us to calculate the frequencies of genes, phenotypes, and genotypes when the frequency of a genetic trait is known. Harmful gene A gene that confirms a harmful trait such that it is reduced to a level at which it is maintained only by recurrent mutation, e.g., the gene for hemophilia A, which has a mutation rate of 1 in 10,000. Hemizygous Inheritance of an X-linked gene in males, e.g. the Xga gene or the gene for hemophilia A is said to be hemizygous in males since they have only one X chromosome. Heterozygous The situation in which allelic genes are different, e.g. the Kk genotype in the Kell BGS or the Fya Fyb genotype in the Duffy BGS. Homologous chromosomes A matched pair of chromosomes, one from each parent, e.g., two #6 chromosomes. Homozygous The situation in which allelic genes are identical, e.g., the KK genotype or the Fya Fya genotype. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 7:06pm On Dec 02, 2014 |
Messenger RNA (mRNA) Type of RNA polymerase using DNA as a template. Contains the codons that encompass the genetic codes to be translated into protein. Mitosis Cell division that results in the formation of two cells, each with the same number of chromosomes as the parent cells, i.e., cell division that forms all new cells except sex cells. Modifying gene A regulatory gene (usually at a different locus than blood group genes) that in some way alters the expression of the blood group genes. Also called suppressor genes. Monozygotic twins Twins derived from a single fertilized ovum, i.e., identical twins. Mutation A permanent inheritable change in a single gene (point mutation) that results in the existence of two or more alleles occurring at the same locus. Blood group polymorphism has been caused by mutations occurring over long periods of time. Nondisjunction The failure of two members of a chromosome pair to disjoin during anaphase. For example, an offspring with the AB/O genotype can be produced if a group AB male mates with a group O female and nondisjunction happens in the father. Northern blot A blotting method used to analyze and detect RNA by using a DNA probe that will hybridize with its complementary RNA strand. Named for its similarity to the Southern blot used to analyze DNA. Nucleic acids Polymers of phosphorylated nucleosides, the building blocks of DNA and RNA. Nucleoside The building blocks of RNA and DNA. Compounds consisting of a purine (adenine or guanine) or pyrimidine (thymine or cytosine) attached to ribose (in RNA) or deoxyribose (in DNA) at the 11 carbon. Nucleoside analogue Synthetic nucleosides that are similar to nucleosides but differ at a key location. When incorporated into DNA, they terminate DNA chains and thus are useful as antiviral drugs. Examples are zidovudine (azidothymidine or AZT) and dideoxyinosine (ddI) used to treat AIDS. Operator A short sequence of nucleotides that controls the adjacent structural (functional) genes. Operon A postulated unit of gene action that consists of an operator and the closely linked functional genes it controls. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by abdulzamali(m): 7:07pm On Dec 02, 2014 |
Are You a JAMB CBT CANDIDATE and you're Writting this upcoming 2015 JAMB... Contact Examruns helpline:08141805939 for assistance... |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 7:09pm On Dec 02, 2014 |
Polypeptides Polymers of amino acids that form the building blocks of proteins. Population genetics The branch of genetics that deals with how genes are distributed in populations and how gene and genotype frequencies stay constant or change. Calculations are based on the Hardy-Weinberg law. Proband The family member whose phenotype leads to a family study. Also called an index case. Proposita A female proband. Propositus A male proband. Recessive Genes are recessive if the phenotype that they code for is only expressed when the genes are homozygous, e.g., le le genes, in the Lewis system or h h genes in the ABO BGS. Recombinant A person who has a new combination of genes not found together on the chromosome in either parent, e.g., an MS/Ns offspring whose parents are Ms/NS and MS/MS. A recombinant results from crossing over in one parent. Recombinant DNA In molecular genetics, artificially made DNA composed of fragments of DNA from different chromosomes (often from different species) that have been joined together (spliced) by genetic engineering. For example, healthcare workers are routinely vaccinated with a recombinant hepatitis B vaccine made by inserting a piece of the hepatitis B virus genome (the part that codes for the HB sAg) into yeast cells via a plasmid. The yeast cells then produce a large amount of HB sAg, which is purified into the vaccine and stimulates the production of protective anti-HB s antibodies. Regulatory genes In the operon model, genes that inhibit an operator gene so that it prevents its functional genes from producing proteins. Restriction endonucleases DNA enzymes of bacterial origin that can cleave DNA at internal positions on a strand because they recognize specific sequences (usually 4-6 base pairs). The enzymes evolved in bacteria as defenses against the invasion of foreign DNA in the form of viruses or plasmids and are used in molecular genetics to chop up DNA at particular locations. Restriction fragment length polymorphisms (RFLP) Regions of DNA of varying lengths that can be cut out of DNA by restriction endonucleases. Because the fragment lengths vary among individuals, they are polymorphic and can be used as genetic markers. Reverse transcriptase An RNA-dependent DNA polymerase that synthesizes DNA from an RNA template. Used by retroviruses like the human immunodeficiency virus (HIV) to make proviral DNA from its RNA genome. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 7:12pm On Dec 02, 2014 |
Sex chromosomes The chromosomes that determine sex. XX in females and XY in males. Sex-linked An outdated term for genes on the X chromosome. Historically synonymous for X- linked since, apart from genes essential for male sex determination, the Y chromosome appears to have few recognized gene loci. Somatic chromosome A non-sex chromosome (soma=body). Synonym is autosome. Southern blot A blotting method developed in 1975 by E.M. Southern that detects restriction enzyme- cleaved DNA by use of a labelled DNA probe that will hybridize with its complementary DNA strand. X-chromosome The sex chromosome present in double dose in females (XX) and in single dose in males (XY). X-linked Genes on the X chromosome, e.g., genes for hemophilia A, hemophilia B, and Xga blood group genes. Y-chromosome The sex chromosome present only in males (XY). |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 8:15pm On Dec 02, 2014 |
Pennyways:plz just finish it, I already got homeostatic sunk into ma head |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 9:27pm On Dec 02, 2014 |
Preboy:alright, I ask permission from Microflux to continue |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 9:36pm On Dec 02, 2014 |
Pennyways:pls, u cn finish it. Weldone |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 9:39pm On Dec 02, 2014 |
Microflux:thanks |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pr0ton: 11:04pm On Dec 02, 2014 |
Pennyways: Methinks we should get settled with one first. I would that Microflux continue. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 6:50am On Dec 03, 2014 |
Pr0ton:boss I'm really sorry for complicating the curriculum, but since I started this, please permit me to round it up. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 7:06am On Dec 03, 2014 |
HORMONES To day we shall study about the hormones and their role in homeostatic process. sensitivity is an important characteristic of all living organisms. it is the ability to respond to external and internal stimuli. to do this, the different organ systems in a complex organisms have to work together. In animals, the co-ordination work is done by two communication networks: the hormones and the nervous system. in this section, we shall study about the hormones and the role they play in co-ordination and homeostatic processes. ENDOCRINE GLANDS Many glands in the mammalian body produce serections. Some glands, like the salivary glands, deliver their secretions to wherever they are needed via ducts. These are known as excrine glands. Others secretory glands do not have ducts. Their secretions are diffuse directly into the bloodstream and transported to wherever they are needed. These glands are known as endocrine glands and their secretion are the hormones. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 7:54am On Dec 03, 2014 |
ENDOCRINE SYSTEM IN HUMANS The endocrine systems is compose of various endocrine glands positions in the human body. These glands may be * discrete like the thyriod and adrenals, or * groups of cells within other organs like the cell in the pancreas that produce insuline. Each endocrine gland may produce one or more hormones. The pitutary is known as the master endocrine gland since many of its hormones influence the activity of others glans, including many endocrine glands. HYPOTHALAMUS This is a small body at the base of the forebrain, just above the pituitary gland. The hypothalamus regulates activities like temperature control, thirst and sleep. It collects information from other parts of the brain and sense organ via nerve impluse; and by monitoring the chemical level of hormones and other chemicals in the blood that flows through it. It passes on the necessary information to the pituitary gland which then regulates the activity, directly of other glands, including the endocrine glands. Thus, the hypothalamus act as a link between the nervous system and the endocrine system. By monitoring the blood, it plays a central role in homeostatic processes. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 9:23am On Dec 03, 2014 |
HORMONES: Secretions of Endocrine Glands Hormones are chemical substances secreted by endocrine glands in response to various stimuli (both internal and external). They circulate in the bloodstream and exert their effects on certain organs known as target organs. These effects may be to speed up (excite) slow down (inhibit), or alter the activities of the target organs. A few hormones like thyroxin and growth hoemones exert their effects on all body cells. Thus, a hormone is usually define as a chemical messenger that is produced in one part of organs and bring about a specific effect in target organs some distance away. Many hormones are involved in homeostatic processes, i.e. processes that maintain a constant internal enviroment. Some hormones control growth and devopment. A hormone may exert its effects on more than one organ at a time. Normally, body responses to hormones are fairly slow, from a few hours to some days. Some body responses, like those occur during growth, sexual maturity and pregnancy, take months and years. An exception, however, is adrenaline which brings rapid body responses. The body only needs small amount of hormones to bring about their effects. These amount in blood are regulated by feedback mechanisms. All hormones are inactibated in the liver and excreted in urine, some within minutes, others within days. Hormones concerned with bringing about long-term effects are secreated continuously to maintain constant level. Serious illness can rise if and endocrine organ malfunction by producing too much or too little of its hormones. Target organs and hormone action A targer organs has cells with special receptor molecules on their surfaces. The appropriate hormone can fit into these receptor molecules and bring about its effects. These effects are usually achieved by 1. affecting the cell permeability to certain substances; 2. promoting protein syntesis; or 3. increasing the activity of certain enzymes. 1 Like |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Pennyways: 8:31am On Dec 04, 2014 |
IMPORTANT HORMONES AND THEIR FUNCTIONS PITUITARY HORMONES The pituitary gland, found just below the hypothalamus, consist of an anterior part and a posterior part. Both part release hormones which are either polypeptides or proteins. Anterior pituitary hormones these hormones consist of 1. Several tropic hormones that regulate the activities of other endocrine glands (through homeostatic mechanisms); 2. The growth hormones; and 3. Prolactin. their secretion are stimulated by chemicals produced by the hypothalamus and transported the pituitary in the bloodstream. Posterior pituitary hormones The anti diuretic hormone (ADH) and oxytocin are produced in the hypothalamus but stored in the posterior pituitary gland. Their secretions are stimulated by nerve impulses from the hypothalamus. THYRIOD HORMONE The thyriod glands, found in the neck close to the larynx, produce three main hormones, the most important being thyroxine . Thyroxine is formed from an amino acid and iodine. Thyroxine regulates the growth and developement of all body cells. It also increases the rate at which glucose is oxidized in body cells, It increases the basal metabolic rate and, hence, heat production. It is therefore, extremely important to control the production of thyroxine. Abnormalities due to thyroxine Undersecretion of thyroxine before maturity causes cretinism. A cretin is physically underdeveloped (dwarfed in size), mentally retarded and sexually immature, in addition to being sluggish (a result of low metabolic rate). Cretinism can be prevented by detecting the condition early and treating with thyroxine supplements. If undersecretion of thyroxine occurs after maturity, the person becomes physically and mentally sluggish, and obese, with a reduced heart rate lowerd body temperature. These effects are mainly due to a low metabolic rate. This condition is know as myxoedema. It can also be treated effectively with thyroxine suppliments. Undersecretion of thyroxine may be due to a defective thyriod or insufficient TSH production by the pituitary. A diet low in iodine also reduces thyroxine production. The thyriod gland comes under prolong stimulation by TSH (caused by a low thyroxine level in the blood). It becomes hyperactive and enlarges to form a hyperplastic goitre. This is seen as a swelling in the front part of the neck. This condition can be cured simply by adding iodine suppliment to the diet. Oversecretion of thyroxine also result in an enlarged thyriod gland, known as exophthalamic goitre. A person with such a condition is hyperactive, irritable, nervous and thin with bulging eyes. These effects are due to a high basal metabolic rate. This condition can be cured by surgically removing part of the thyriod gland or destroying some part of the thyroid cells by rediation. PARATHYROID HORMONE Attached to the thyroid gland are four tiny glands called parathyroid glands. These secrete the parathyroid hormone, which together with the thyroid hormone, calcitonin, regulates blood calcium levels. The parathyroid hormone raises the level of calcium ions in blood by * releasing calcium from bones; * increasing calcium absorption in the guts and * reducing calcium excretion by the kidneys. calcitonin lowers the level of calcium ions in blood by reversing these effects. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 3:07pm On Dec 09, 2014 |
DelePhd:so how much is the Book? |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by DelePhd: 9:42am On Dec 12, 2014 |
iamdollypee: #1,000 |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Nobody: 2:45pm On Dec 12, 2014 |
DelePhd:I sent an email msg to U concerning the PDF file of the book.. But you didn't reply.. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by DelePhd: 11:16pm On Dec 12, 2014 |
iamdollypee: I did not get your e-mail. Please resend to methyldelene@yahoo.com |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Victar(m): 10:46am On Dec 18, 2014 |
Do we now have a group on WhatsApp cus nothing seems to be happening here.... |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by DelePhd: 12:54am On Jan 02, 2015 |
This video beautifully summarizes Explicit Biology and Explicit Chemistry as the student-trusted and success-oriented duos. Watch, like and share. https://www.youtube.com/watch?v=3AV9VjFayKE |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Vickoscatter(m): 2:54pm On Oct 25, 2016 |
Microflux: I don't think no. 1 answer is E, the answer is C, because as you said, chromosomes are thread-like, gene-carrying bodies in the cell nucleus and the question asks for the carrier of the hereditary characters in plants and animals, so if genes are the unit of inheritance or the hereditary characters, and chromosomes are gene-carrier, that makes chromosomes the carrier of the hereditary characters in plants and animals |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Hardebaryor(m): 7:57am On Dec 21, 2017 |
DelePhd:Hello sir can you please help me with the explicit biology pdf files. The hard copy is not currently in market. My email is Ibrahimkukar2@gmail.com |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Posh(m): 8:16am On Dec 21, 2017 |
Microflux:..... Fertilisation is the fusion of the spermatozoon with d ovum...nd nt gametogenesis. Gametogenesis is the production of sperms thro spermatogenesis or ovum..thro..oogenesis.. Nice write up.. Am impressed.. 1 Like |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by DelePhd: 5:06pm On Dec 21, 2017 |
Hardebaryor: It is now available, in fact they now have "Explicit Use of English" for JAMB-UTME. Vheck Abiodun or Abikoye bookshop around Yaba, Tejuosho. |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by Hardebaryor(m): 5:12pm On Dec 21, 2017 |
DelePhd:I live in ife sir and i come to Osogbo once in a while. When will it be available in tgose two areas |
Re: Nairaland Jamb Tutorial Centre {Biology Thread} by DelePhd: 11:09am On Dec 23, 2017 |
Hardebaryor: Check Apex Tutors at Mayfair in Ife and David Great Tutors in Ife by January. |
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