Unit 5: Heredity Flashcards

Question

Sex Chromosomes

Answer 1

23rd pair of chromosomes that determine the biological se of the offspring - females = xx - males = xy 50% chance male or female for each offspring - X chromosome is LARGE and contains necessary information for survival - Y chromosome is small and only contains codes for male reproduction organs

Answer 2

-decided by the genes on the x- chromosome - for sons to have the trait, the mom MUST HAVE IT - for daughters to have recessive trait, DAD MUST HAVE IT - males CANNOT be heterozygous, they either have it or they don't b/c they only have 1 x chromosome ex. xA y normal, xa y colorblind - more likely to be seen in males - females are more normal bc XA XA and XAXa are normal, XaXa are colorblind - have normal Punnett square except gene decided by the little a or big A on the X

Answer 3

person has the gene but isn't affected (interchangeable for heterozygous)

Answer 4

code for what type of trait it is (dominant vs recessive + sex linked vs autosomal)

Answer 5

1. Two unaffected have affected child (always autosomal recessive) 2. Two affected have 100% affected kids (always autosomal recessive) 3. even distribution between male and female 4. trait has possibility of skipping generations

Answer 6

1. Two affected can have unaffected kid (key giveaway) 2. Two unaffected have 0% of having affected kid (key giveaway) 3. even distribution between male and female generations 4. trait doesn't skip generation

Answer 7

1. more affected males then females 2. affected mom MUST have 100% affected sons 3. affected female MUST have affected father

Answer 8

1. male and female affected equally 2. affected female have 50% affected kids 3. affected males have 100% affected daughters If no other patterns match it's x-linked dominant (uncommon)

Answer 9

physical location of a gene on a chromosome (larger chromosome = more loci)

Answer 10

disregard law of independent assortment b/c GENES ON SAME CHROMOSOME - leads to different phenotypic ratios * Linked traits have way more offspring with same phenotype as parents* - crossing over won't create new genetic combinations if loci are close

Answer 11

Parental Genotype: the genotype of the parents ( in linked traits you see more of them) Recombinant Genotype: new gene combinations from crossing over (linked genes = less seen genotypes)

Answer 12

- traits that are controlled by more that one gene ( skin color, eye & hair color, height) - can't make a punnett square for these POLYGENETIC TRAITS = WIDE RANGE OF PHENOTYPES

Answer 13

- when the mutation is dominant to the healthy gene ex Marfan syndrome: MM = not even born/death Mm= affected + alive mm = healthy *Prescence of one dominant allele = affected

Answer 14

- when the dominant allele is incompletely dominant over the reccessive (partially expressed traits) * BLENDED/MIX of traits in the phenotype ex flower: R = red, r = white, Rr = pink a monohybrid cross is the same but the phenotypic ratio would change to 1: 2: 1 bc new phenotype created with heterozygous

Answer 15

when 2 or more alleles are equally dominant and equally expressed (neither is recessive) ex: human blood A & B are dominant, O is recessive AA & AO = type a blood BB & BO = type b blood AB = type AB blood (codominant) OO = o blood (recessive trait)

Answer 16

- mom (egg) has EVERYTHING (DNA, organelles, cytoplasm that's why it's so big, dad only caries 23 chromosomes - all offspring have 100% mom's mitochondria (mitochondria make themselves, nucleus doesn't have code for them) INHERITANCE OF MITOCHONDREAL DNA IS 100% MATERNAL = affected mom means 100% affected kids (dad DNA doesn't matter at all) - chloroplasts follow same pattern in plants

Answer 17

changes in the environment lead to changes in the gene expression which changes the organisms' phenotypes * Organisms don't mutate their genes, only expression changes ex. foxes turn white in winter and red in summer