Biology Terminology

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BIOLOGY TERMINOLOGY

INHERITANCE

Traits: characteristics has which are passed from your parents to theoffspring

George Mendel: Father of Genetics

Mendels Rules of Heredity

- Individual carry two genes fore each trait but pass down only one- One gene is dominant over another

Dominant Genes: gene that is stronger from the other

Punnett Square: a diagram that is used to predict an outcome of aparticular cross or breeding experiment.

Purebred (homozygous): gene combination involving 2 dominant or 2recessive genes (consists of the same pair of genes)

Hybrids (heterozygous): genes consists of 2 different genes

Genotype: gene combination for a trait

Phenotype: the physical feature resulting from a genotype

Recessive; genes which appearance covered by the other genes

Heredity (inheritance): process of passing of traits from parents to offspring

Complete dominance: inheritance of the traits when one trait completelycovered the appearance of the other genes

Alleles: two forms of a gene (dominant & recessive)

Monohybrid cross: cross involving a single trait

Parental P1 generation: the parental generation in a breeding experiment

F1 generation: offspring in a breeding experiment

From breeding individuals from the P1 generation

F2 generation: the second-generation offspring in breeding experiment

From breeding individuals from the F1 generation

Incomplete Dominance: where the phenotype and genotype ratios areidentical and results (the results will blend)

Co-dominance: where both alleles are equally expressed


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DNA: Acronym for Deoxyribo Nucleic Acid. Inherited genetic code

Gene: unit of heredity that is transferred from a parent to offspring. They

coded for to determine some characteristic of the offspring.

Chromosome: a threadlike structure of nucleic acids and protein found in thenucleus of most living cells, carrying genetic information in the form of genes.

Autosomes: one type of chromosomes that determine the physical feature ofan organism (chromosome no. 1-44 or pair no. 1-22)

Sex chromosomes: one type of chromosomes that determine the gender ofan organism (chromosome no. 45-46 or pair no. 23)

Karyotyping: A picture of the chromosomes in a cell that is used to check for

abnormalities. A karyotype is created by staining the chromosomes with dyeand photographing them through a microscope. The photograph is then cut upand rearranged so that the chromosomes are lined up into correspondingpairs.

Carrier: an individual who is phenotypically normal but genetically carriesdefective genes.

CELL DIVISION

Meiosis: The process of two consecutive cell divisions in the diploidprogenitors of sex cells. Meiosis results in four rather than two daughter cells,

each with a haploid set of chromosomes.


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Mitosis: type of cellular reproduction where a cell will produce an

identical replica of itself with the same number and patterns of

genes and chromosomes.

Haploid: half set number of chromosomes

Diploid: full set number of chromosomes

Homologous pair: chromosomes that are paired during the production of ofsex cells in meiosis. Such chromosomes are alike with regard to size andalso position of the centromere. They also have the same genes, but notnecessarily the same alleles,

Nucleus: The cellular organelle in eukaryotes that contains the geneticmaterial. The center of a cell, where all of the DNA, packaged in

chromosomes, is contained.

Gametes: sex cells that contain one set of genetic information.

Fertilization: the joining or fusion of a male gamete and a female gamete.

The new cell that is formed divides over and over again by mitosis. This

creates the many cells that eventually form a new individual.
http://en.wikipedia.org/wiki/Geneshttp://jumpto%28%27%23chromosomes%27%29/http://jumpto%28%27%23meiosis%27%29/http://jumpto%28%27%23allele%27%29/http://jumpto%28%27%23allele%27%29/http://jumpto%28%27%23meiosis%27%29/http://jumpto%28%27%23chromosomes%27%29/http://en.wikipedia.org/wiki/Genes


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There are FOUR main stages of Meiosis:

Prophase:- Nuclear membrane disappears.

- Nucleolus disappears.

- chromosomes coil

- assembly of spindle apparatus completed.

Metaphase:

Chromosome lined up in equatorial plate of cell


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Anaphase:

fibers of spindle apparatus pull each pair of sister chromatids apart. One

goes to one polar of the cell, the other goes to the other pole.

Telophase:

nuclear membrane re-forms.

Nucleolus re-forms.

Chromsomes uncoil.

Spindle apparatus disassembled.

BUILDING BLOCKS OF DNA

Nucleotide: A subunit of DNA consisting of a nitrogenous base (adenine,guanine, thymine, or cytosine in DNA, a phosphate molecule, and a sugarmolecule (deoxyribose in DNA). Thousands of nucleotides are linked to form aDNA molecule.

Legend:

Circle: Phosphate group

Square: Sugar

Rectangle: Nitrogenous Bases

Base Pairing Rules: AdenineThymine, Cytosine---Guanine


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GENETIC DISORDERS

Sex linked (X-linked): The transmission to successive generations of

traits that are due to alleles at gene loci on a sex chromosome.

Autosomal inheritance:

- no individual being a carrier dominant- Recessive: heterozygous individual- Example of the disorders: achondroplasia (dwarfism), albinism,

polidactily (many fingers)

Turners Syndrome:

Genetic disorder with short stature, undifferentiated (streak) gonads,and variable abnormalities such as webbing of neck, low posterior hair

line, increased carrying angle of elbow, cubitus valgus, and cardiacdefects. The genotype is XO (45, X) or X/XX or X/XXX mosaic. Thephenotype is female.

Downs Syndrome:

mongoloid features, short phalanges, widened space between the firstand second toes and fingers, and moderate to severe mentalretardation; associated with a chromosomal abnormality, usually trisomyof chromosome 21.

Klinefelters Syndrome:

smallness of testes with fibrosis and hyalinization of seminiferoustubules, variable degrees of masculinization, azoospermia, andinfertility, and increased urinary gonadotropins. It is associated typicallywith an XXY chromosome complement although variants include XXYY,XXXY, XXXXY, and various mosaic patterns.

Cri du chat: syndrome occurs when a piece of chromosomal material ismissing from a particular region on chromosome 5. Individuals with thissyndrome have unusual facial features, poor muscle tone (hypotonia),small head size (microcephaly), and mental retardation. A classicfeature of the syndrome is the cat-like cry made by infants with thisdisorder.

Albinism: an inherited condition present at birth, characterized by a lackof pigment that normally gives color to the skin, hair, and eyes. Manytypes of albinism exist, all of which involve lack of pigment in varyingdegrees. The condition, which is found in all races, may beaccompanied by eye problems and may lead to skincancerlater in life.
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