BIO FIRST QUIZ

• genetics


  Study of genes and their transmission from one generation to the next.
• genes


  DNA sequences that contain instructions for building proteins.
• genomes


  the complete genetic material of an organism along with its noncoding nucleic acid sequence
• Your genotype is the genetic basis of your phenotype.
• chromosomes


  Structures within the nucleus, composed of DNA and protein.
• autosomes


  first 22 pairs of body cells
• allosome


  last 1 pair; sex cell
• karyotype


  The diploid chromosomal complement in any species. A composite display of all of the chromosomes of an individual. Shows all 23 pairs of chromosomes lined up side-by-side.
• gene locus (plural loci)


  the location of a specific pair of genes
• a pair of genes


  normally, both genes have the same structure and function
• alleles


  alternative versions of the same gene pair; result of mutation
• homologous chromosomes

  • One member of each pair is inherited from each parent.
  • Look alike (size, shape, banding pattern)
  • Not identical: may have different alleles of particular gene.
• homozygous


  Two identical alleles at a particular locus

  (zygous means “yoked,” or joined together)
• heterozygous


  Two different alleles at a particular locus

  (hetero- means “different”)
• hemizygous


  A term that describes a person who has only one copy of a gene rather than the usual two copies.
• dominant

  Masks or suppresses the expression of its complementary allele.

  Always expressed, even if heterozygous.
• recessive

  Will not be expressed if paired with a dominant allele (heterozygous).

  Will only be expressed if the individual is homozygous for the recessive allele.
• genotype


  An individual's complete set of alleles.
• phenotype


  Observable physical and functional traits. Your phenotype is determined not only by the alleles you inherit from your parents (your genotype), but also by environmental factors and lifestyle choices
• gregor mendel

  • University-educated Austrian monk.
  • Worked (controlled breeding) with pea plants in the 1850s in Austria.
  • Chose pea plants because they were cheap, easy to grow, and mating with plants is easy.
  • Did multiple genetic experiments to develop basic rules of inheritance. 
  • Law of segregation
  • Law of independent assortment
  • Law of dominance
• law of segregation


  Gametes carry only one allele of each gene
• law of independent assortment


  Genes for different traits are separated from each other independently during meiosis. This applies only if the two genes in question are on different chromosomes.
• A Punnett square provides a simple way to represent patterns of inheritance of alleles and to predict the probability that a particular genotype will be inherited
• complete dominance

  • the dominant allele of a gene at a locus is fully expressed, suppressing the recessive allele, resulting in a dominant phenotype.
  • The dominant overpowers the recessive
  • Recessive is only expressed in Homozygous recessive parents
• incomplete dominance


  Type of gene interaction in which in a heterozygous condition, both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype. It is also called partial dominance.
• co-dominance

  Occurs when the contributions of both alleles are visible in the phenotype.

  It means that both alleles are expressed EQUALLY.
• sickle-cell anemia


  this is an example of codominance. Sickle-cell anemia is a disease caused by one of two alleles involved in the production of hemoglobin for red blood cells.
• Polygenic traits are usually distributed within a population as a continuous range of values
• sex-linked inheritance

  • Refers to inheritance patterns that depend on genes located on the sex chromosomes.
  • 23rd pair of chromosomes
  • Not homologous
  • X and Y chromosomes carry different genes
• Hemophilia or bleeder’s disease.


  this is an example of sex-linked inheritance. Hemophilia is usually an inherited bleeding disorder in which the blood doesn't clot properly. This can lead to spontaneous bleeding as well as bleeding following injuries or surgery. Blood contains many proteins called clotting factors that can help to stop bleeding.
• nondisjunction 


  Failure of homologous chromosomes or sister chromatids to separate properly.
• nondisjunction in meiosis i


  Nondisjunction during Meiosis I results in two gametes each with an extra chromosome (n+1) and two gametes each missing a chromosome (n-1)
• nondisjunction in meiosis ii


  Nondisjunction during Meiosis II results in two normal haploid gametes (n), one gamete with too many chromosomes (n+1), and one gamete with one too few chromosomes (n-1)
• Nondisjunction is a lack of separation of chromosomes during anaphase of cell division (either during mitosis or either round of meiosis). The effect of nondisjunction is to produce daughter cells (or, in the case of meiosis, gametes) with incorrect chromosome counts. They will either have one too few or one too many chromosomes.
• down syndrome (47, 21+)

  • Trisomy 21
  • Simian crease
  • Characteristically short
  • Epicanthic fold in the eye corner
  • Mental development is retarded.
• klinefelter syndrome (47, xxy)

  • Taller less muscular body than males their age.
  • Broader hips and longer legs
  • Larger breasts
  • Weaker bones 
  • Lower energy level
  • Smaller penis and testicles
  • Delay in puberty or go a parcel amount
  • Less facial and body hair following puberty
• turner syndrome (45, xo)

  • Monosomy
  • All or part of one X chromosome is absent
  • Short stature, webbed neck, rudimentary ovaries, underdeveloped breasts, broad-shield like chest
  • Female
• jacob syndrome (47, xyy)

  • Extremely tall
  • No facial and body hair
  • Breast development
  • Osteoporosis 
  • Feminine fat distribution
  • Small testis
  • Male
• patau syndrome

  • 47 chromosomes (13+)
  • Trisomy 13
  • Cleft palate
  • Polydactyly
  • Low set of ears
  • Abnormal genitalia
  • Overlapping of fingers over thumb
  • Cutis aplasia (missing portion of the skin or hair)
  • Heart and kidney defects
• edward syndrome

  • 47 chromosomes (18+)
  • Trisomy 18
  • Small head
  • Low set malformed ears
  • Abnormally small jaws
  • lip/cleft palate
  • Clenched hands
  • Underdeveloped thumbs or nails
  • Very low rate of survival due to hear and kidney abnormalities and other organ disorder
  • Polydactyly