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45 Cards in this Set
- Front
- Back
pleiotropy - define and give a human example
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positive or negative effects that a single gene can have on 2 or more trait
Example - Marfan syndrome |
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polygenic traits - define and give examples
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traits affected by interaction of several genes and even environmental factors
Example - hair color, skin color, eye color, height |
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Himalayan rabbit - effect of temperature on fur color
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enzyme in fur only active when temp is below 91 degrees F - if warmer, can't make melanin - leading to lighter fur - so extremities lose heat fastest and therefore have dark fur
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Codominance
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when two alleles are both expressed - example A allele and B allele give AB blood type
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Incomplete dominance
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when heterozygotes show mixture of traits - eg red and white snapdragon give pink flowers
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multiple alleles
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3 or more alleles for a trait - eg A, B and O
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Blood typing
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A - IaIA or Iai 39%
B - IbIB or Ibi 12% AB - IAIB 4% O - ii 45% |
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Universal donor
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O-
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Universal recipient
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AB+
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Antigens (agglutinogens)
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blood proteins on red blood cell membranes
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Antibodies (agglutinin)
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made by WBC, against proteins in blood plasma, bind to foreign substances and destroy them - helps fight infection
Eg - type B blood makes anti-A anbibodies |
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Rh factor
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another blood proteins - 85% of population is positive for Rhesus factor
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Which types can each blood type give blood to and get blood from
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A - give to A, AB, get from O, A
B - give to B, AB, get from O, B AB - get from everyone, give to AB O - get from O - give to all |
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Blood
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5 L, 7-8 % body weight
functions - carry nutrients and oxygen to cells, carry CO2 and other wastes away from cells, help defend body against disease |
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Composition of blood
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Plasma
red blood cells (erythrocytes) white blood cells (leukocytes) platelets |
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dihybrid cross
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cross involving two traits (eg. height and color)
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Theory of independent assortment
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alleles for 1 trait sort independently of alleles for another trait
eg. hgt and pod color in pea plants |
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Punnett Square
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Box diagram with alleles from 1 parent across the top and alleles from the other parent on the side.
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Genetics
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study of heredity
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Heredity
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passing on of traits from parents to offspring
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Gregor Mendel
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Mid 1800's
monk disproved "blending" theory called genes "factors" |
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self-pollination
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male and femal on one plant - pollen to stigma of same plant
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cross-pollination
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2 plants - pollen from 1 plant to stigma of another
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anther
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part of male reproductive organ - makes pollen
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stigma
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tip of female reproductive organ - leads to egg
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chracteristics of pea plants
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round or wrinkled, tall or short, green or yellow (pod?), purple or white flower
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gene
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segment of DAN that codes for a specific trait - found at a specific location called a locus
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allele
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different forms of some gene -
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Dominant allele
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expressed as capital letter - always expressed - eg T (tall)
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Recessive allele
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hidden in presence of dominant eg t (short)
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Homozygous
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purebred - 2 of same allele - example TT
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Heterozygous
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2 different alleles - eg Tt
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phenotype
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physical appearance - eg eye color
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genotype
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letters of genetic makeup - eg Tt
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P generation
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parental generation - members of original cross
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F1 generation
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first generation of offspring of P
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F2 generation
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2nd generation - offspring of offspring
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monohybrid cross
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cross involving one trait
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dihybrid cross
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cross involving 2 traits
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probability
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branch of math that predicts chances that a certain event willl occur
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Theory of segregation
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onely one of the two allels for a trait go into creating each gamete (in meiosis) - segregate as units
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testcross
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cross to determine genotype of unknown - always cross with homozygous recessive
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diploid
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pairs of chromosomes - 2n
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mutation
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alters a gene's molecular structure and message traits
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epistasis
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examples - fur color in Labrador retrievers, comb shape in poultry
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