unit 7 Flashcards

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1
Q

Blending Hypothesis vs. Particulate Hypothesis

A

blending: that genetic material from the two parents blends together (the way blue and yellow paint blend to make green)
particulate: the idea that parents pass on discrete heritable units (genes)

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2
Q

Model that we use today and why?

A

particulate hypothesis
why: we inherit units that determine our traits. this is even true when we talk about incomplete dominance which is where we do see what seems to be blending of a trait

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3
Q

P1,F1,F2 generations

A

P: parental generation
F1: first filial (offspring of P generation)
F2: offspring of F1 generation

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4
Q

Traits

A

Characteristics that are inherited; Mendel reasoned that in the F1 plants, the heritable factor for white flowers was hidden or masked in the presence of the purple-flower factor He called the purple flower color a dominant trait and the white flower color a recessive trait. The factor for white flowers was not diluted or destroyed because it reappeared in the F2 generation

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5
Q

true-breeding

A

mendel used true breeding as in he avoided the appearance of unexpected traits in the offspring… he chose plants that only code for one version of the particular trait being studied

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6
Q

alleles

A

alternative versions of a gene
simply variations in a gene’s nucleotide sequence

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7
Q

Dominant allele vs recessive allele

A

dominant: capital letter; only requires one allele for the trait to be physically seen
recessive: lowercase letter; requires 2 alleles

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8
Q

4 concepts to Mendel’s model explain each

A
  1. Alternative versions of genes account for variations in inherited characters
  2. or each character, an organism inherits two alleles, one from each parent (23 mom, 23 dad)
  3. f the two alleles at a locus differ, then one (the dominant allele) determines the organism’s appearance, and the other (the recessive allele) has no noticeable effect on appearance
  4. (the law of segregation), the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes
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9
Q

Independent assortment vs. Law of segregation

A

independent assortment: each pair of alleles segregates independently of any other pair during gamete formation
law of segregation: two alleles for a heritable character segregate during gamete formation and show up in different gametes

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10
Q

Punnett Squares (Be able to work these out)

A
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11
Q

Monohybrids vs. dihybrids

A

monohybrids: Looking at one individual trait. These are your traditional Punnett Squares.
dihybrids: Looking at Two traits at once

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12
Q

Homozygous Dominant

A

An organism with two identical alleles for a character is said to be homozygous for the gene controlling that character (AA)

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13
Q

homozygous recessive

A

An organism with two identical alleles for a character is said to be homozygous for the gene controlling that character (aa)

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14
Q

heterozygous

A

An organism that has two different alleles for a gene is said to be heterozygous for the gene controlling that character (Aa)

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15
Q

Carriers

A

are heterozygous individuals who carry the recessive allele but are phenotypically normal

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16
Q

Phenotype vs genotype

A

phenotype: physical appearance
genotype: genetic make up/specific combination of alleles (AA, Aa, aa)

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17
Q

Ratios

A

complete dominance: genotypic ratio (AA:Aa:aa) phenotype ratio (dominant:recessive)
imcomplete and codominance: genotypic and phenotypic are the same since there are 3 phenotypes (AA:Aa:aa)

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18
Q

Probability Rules (Be able to work out these problems)
Addition

A

probability that any one of two or more mutually exclusive events will occur is calculated by adding together their individual probabilities, the word OR

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19
Q

Probability Rules (Be able to work out these problems)
Multiplication

A

probability that two or more independent events will occur together is the product of their individual probabilities, the word AND

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20
Q

Degrees of dominance (Be able to work out these problems)

A
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21
Q

complete dominance

A

occurs when phenotypes of the heterozygote and dominant homozygote are identical
expresses 2 phenotypes equally
Example: Red (AA, Aa) or White Flowers (aa)

22
Q

Incomplete dominance

A

mixture of two phenotypes…Like Painting
Example: Red (AA) Pink(Aa) or White Flowers (aa)

23
Q

Codominance

A

phenotypes of heterozygote and dominant homozygote are expressed the same
Example: Red (AA) Spotted Red and White (Aa) White flowers (aa)

24
Q

Multiple alleles
Blood type (A,B,O)

A

Blood type (A,B,O)
Most genes exist in populations in more than two allelic forms
For example, the four phenotypes of the ABO blood group
there are more than 2 options and an example of codominance with O being the only recessive allele

25
Q

Pleiotropy

A

The ability of a single gene to have multiple effects.
responsible for multiple symptoms of certain hereditary diseases

26
Q

Epistasis

A

The phenotypic expression of one gene alters the expression of another independently inherited gene
For example, in Labrador retrievers and many other mammals, coat color depends on two genes

27
Q

polygenic inheritance

A

genetic and environmental factors collectively influence the phenotype

28
Q

Quantitative characters

A

trait varies in population along a continuum…indicates polygenic inheritance
ex. skin and hair color

29
Q

multifactorial

A

genetic and environmental factors collectively influence phenotype

30
Q

Pedigree
Know how to read and draw these
Be able to identify what type of disorder is present in a family (dominant disorder vs. recessive disorder)

A

diagram of a family tree showing the occurrence of inheritable traits

31
Q

Thomas Morgan
Know the two Experiments
Know what was discovered from each experiment and its importance.

A
  1. Morgan mated male flies with white eyes (mutant) with female flies with red eyes (wild type) Morgan concluded that the eye color was related to the sex of the fly…More specifically found on the X Chromosome
32
Q

Know the two Experiments
Know what was discovered from each experiment and its importance.

A

Alfred Sturtevant, one of Morgan’s students, constructed a genetic map, an ordered list of the genetic loci along a particular chromosome, shows how certain wing shape and body size are inherited togethe

33
Q

Know the two Experiments
Know what was discovered from each experiment and its importance.

A

traits can be carried on sex-linked chromosomes
gene linkage- found on the same chromosome relatively close together

34
Q

Wild type vs mutant type

A

wild type: phenotype most commonly observed in natural populations; refers to individual with that phenotype
mutant: alternative to the wild type

35
Q

Sex chromosomes

A

a larger X chromosome and a smaller Y chromosome
Only the ends of the Y chromosome have regions that are homologous with corresponding regions of the X chromosome

36
Q

XX vs XY chromosomes

A

xx: female
xy: male

37
Q

SRY gene

A

SRY gene on the Y chromosome codes for all maleness

38
Q

The X chromosome vs the Y chromosomes

A

x: Genes on the X chromosome are called X-linked genes; The X chromosomes have genes for many characters unrelated to gender
y: Genes on the Y chromosome are called Y-linked genes; Most Y linked genes help determine sex

39
Q
  1. X-linked genes
  2. Males are more likely to have X-linked disorders why?
    3.Examples:
    Be able to work these problems out.
A
  1. Genes on the X chromosome specifically
  2. This is due to the fact that they only need 1 copy to express the trait vs. two copies, A female needs two copies of the allele (homozygous) & A male needs only one copy of the allele (hemizygous)
  3. Color blindness, Duchenne muscular dystrophy, Hemophilia
40
Q

Y-linked genes
Hemizygous
Be able to work these problems out.

A

genes specifically found on the Y chromosome ex: SRY chromosome for maleness
hemizygous: one copy of the allele

41
Q

X inactivation

A

In mammalian females, one of the two X chromosomes in each cell is randomly inactivated during embryonic development

42
Q

Calico cats (x-inactivation)
Why does this only happen in females?

A

If a female is heterozygous for a particular gene located on the X chromosome, she will be a mosaic for that character
ex of x-inactivation and x-linked traits and codominance
examples are on google form we did

43
Q

Gene linkage (Be able to tell which genes are most likely to be inherited together)

A
44
Q

Linked genes

A

linked: Genes located on the same chromosome that tend to be inherited together

45
Q

recombinant genes

A

recombinant: how often the genes are broken apart from crossing over (called that when happening) still on the same chromosome but crossing over can change that

46
Q
  1. Linkage maps
  2. Mapping distance
  3. % vs. map units
A
  1. is a genetic map of a chromosome based on recombination frequencies
  2. Distances between genes can be expressed as map units
  3. one map unit represents a 1% recombination frequency, how often crossing over occurs
47
Q

Recombination frequency means what

A

the farther apart two genes are the higher the probability that a crossover will occur between them (less likely inherited together)
the higher the recombination frequency the less likely they will be inherited together

48
Q

Recombination frequency near 50% mean

A

physically linked being found on the same chromosomes but not genetically unlined meaning they are not likely to be inherited together than any other trait

49
Q

Cystic fibrosis

A

recessive trait
results in defective or absent chloride transport channels in plasma membranes leading to a buildup of chloride ions outside the cell

50
Q

sickle cell disease

A

recessive trait
causes red blood cells to be cresent shaped and less efficient at carrying oxygen

51
Q
A