Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DAT Biology > 6. Heredity + > Flashcards

6. Heredity + Flashcards

1
Q

Gene

A
  • genetic material on a chromosome for a trait
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Locus

A
  • location on chromosome where gene is located
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Allele

A
  • variance of genes such as different color
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Homologous Chromosomes

A
  • a pair of chromosomes that contain same genetic material (gene for gene).
  • each parent contributed 1 of the chromosome pair and thus different alleles might exist
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Law of Segregation

A
  • one member of each chromosome pair migrates to opposite pole so that each gamete is haploid
  • occurs in anaphase I
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Law of Independent Assortment

A
  • migration of homologues within one pair of chromosomes doesn’t influence migration of other homologous pairs.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Test Crosses

A
  • monohybrid: test one gene
  • dihybrid: test two genes (on different chromosomes)
  • unknown dominant genotype x homozygous recc to determine if hetero or homo dominant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Incomplete Dominance

A
  • blending of expressions of alleles
  • unique hetero phenotype
  • R = red, r = white, Rr= pink
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Codominance

A
  • both inherited alleles are expressed

- ex. blood type. blood type AB is codominance of A and B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Multiple Alleles

A
  • blood groups have three alleles, A, B, O, 6 genotypes
  • AO or AA -> A type
  • BO or BB -> B type
  • AB -> codominant AB type
  • OO -> O type
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Epistasis

A
  • one gene affects phenotypic expression of second gene
  • ex. pigmentation. one gene turns on production of pigment, another gene controls color or amount. if first gene is turned off, then no pigment is produced. ex. fur color in mice
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pleitropy

A
  • single gene has more than 1 phenotypic expression
  • ex. gene in pea plants that codes for seed texture also influences starch metabolism and water uptake
  • ex. sickle cell anemia leads to diff health conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Polygenic Inheritance

A
  • interaction of many genes to shape a single phenotype w/ continuous variation (height, skin color)
  • opposite of pleitropy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Linked Genes

A
  • two or more genes that reside on same chromosome and cannot separate independently because they are physically connected (inherited together)
  • linked genes exhibit recombination about 18 % of time
  • greater recomb. freq. (above 18%) means farther distance of genes on same chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Linkage Map

A

B-V is 18% A-V is 12%, and B-A is 6%

B—–A————-V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Sex-Linked

A
  • single gene resides on sex chromosome
  • when male (XY) receives an X from mother, whether it is dominant or recessive, it will be expressed bec there is no copy on Y chromosome
17
Q

Sex-influenced

A
  • can be influenced by sex of individual carrying trait

- ex. Bb female not bald, Bb male is bald

18
Q

Sex Chromosomes v. Autosomes

A
  • sex chromosomes: pair of homologous chromosomes that doesn’t have exactly the same genes, X, Y
  • autosomes: all other chromosomes
19
Q

Hemophilia

A
  • sex-linked recessive
  • hemophiliacs cannot properly form blood clots and in worst cases can die from minor injuries by bleeding to death
  • in order for female to be a hemophiliac, she must have two copies of the defective allele, a male needs only one defective copy -> as a result, hemophilia and other sex-linked genetic defects are much more common in males.
  • heterozygous females have normal clotting abilities but are said to be carriers
20
Q

Penetrance

A
  • probability an organism w/ a specific genotype will express a particular phenotype
21
Q

Expressivity

A
  • term describing variation of phenotype for a specific genotype
22
Q

X-inactivation

A
  • during embryonic development in female mammals, one of two x chromosomes does not uncoil into chromatin -> dark and coiled compact body chromosome (barr body) -> can’t be expressed
  • either chromosome can be inactivated -> genes in female will not be expressed similarly, so all cells in a female mammal are not necessarily functionally identical (some have one x inactivated, others have the other x inactivated) (calico cats)
  • what does this mean for sex-linked defects such as hemophilia? carrier female (Hh) is usually normal but it is possible that all cells producing the clotting factor H are inactivated -> smae symptoms of hemophilia as a male
23
Q

Nondisjunction

A
  • failure of chromosme separation
  • failure of sister chromatids to separate during anaphase of mitosis
  • failure of homologous chromosmes to separate during anaphase I of meiosis
  • failure of sister chromatids to separate during anaphase II of meiosis
24
Q

Mosaicism

A
  • nondisjunction in mitosis during embryonic development

- fraction of body cells, those descendent of a cell where nondisjunction occurs, have an extra or missing chromosome

25
Q

Polyploidy

A
  • all chromosomes undergo meiotic nondisjunction and produce gametes w/ twice the number of chromosomes.
  • common in plants
26
Q

Point Mutation

A
  • single nucleotide changes causing substitution, insertion, or deletion (latter 2 could cause frameshift)
  • transition mutation: purine to purine or pyrim to pyrim
  • transversion mutation: purine to pyrim or pyrim to purine
27
Q

Aneuploidy

A
  • genome w/ extra/missing chromosome
  • often caused by nondisjunction
  • down syndrome (trisomy 21)
  • turner syndrome: nondisjunction in sex-chromosome. resulting in abnormal gametes: XX, XY, O. zygote XO -> sterile, physically abnormal
  • Klinefelter: XXY
28
Q

Chromosomal Aberrations

A
  • duplications: chromsome segment repeated on same chromosome
  • inversion: chromosome segment rearranged in reverse on same chromosome
  • translocation: segment of chromosome moved to another chromosme. sometimes can result in down syndrome. ex. translocation of segment from 21 to 14 - > individual would inherit three copies of a segment of chromsome 21 (two chromsomes 21 and 14/21 chromosome) -> same phenotypic effect as trisomy 21
29
Q

Mutagenic Agents

A
  • include cosmic rays, xrays, uv rays, radioactiity, chemical compounds (cholchicine -> inhibit spindle formation), mustard gas.
  • mutagenic agents are generally also carcinogenic
  • proto-oncogenes stimulate normal growth, if mutated become oncogenes -> cancer
30
Q

Genetic Disorders

A
  • Autosomal recessive:
    a. PKU - inability to produce proper enzyme for phenylalanine breakdown
    b. cystic fibrosis - fluid buildup in tracts
    c. Tay-sachs -lysosome defect, can’t breakdown lipids for normal brain function
    d. sickle cell - defective hemoglobin do to subst mutation
  • Autosomal dominant
    a. Huntington’s - degenerate nervous system disease
  • Sex-linkd recessive
    a. hemophilia - abnormal blood clotting
    b. color blindness
    c. duchenne - muscular dystrophy
  • Chromosomal
    a. down syndrome
    b. turner - XO
    c. klinefelter - XXY
    d. Cri Du Chat - deletion on chromosome 5
  • turner’s doesn’t usually cause mental retardation, but downs, kline, and cri du chat do.
31
Q

Forward vs. Backward Mutations

A
  • forward: already mutated organism mutates again

- backward: already mutated goes back to original

32
Q

Extranuclear Inheritance

A
  • extranuclear genes found in mitochondria and chloroplasts.
  • defects in mitochondria’s DNA can reduce ATP production
  • mitochondria all come from mother, so all related diseases are inherited from mother.
  • mitochondria have their own ~ 70S ribosomes that make mitochondrial proteins w/in mitochondrial matrix
33
Q

Homozygous

A
  • two copies of same allele

- AA or aa

34
Q

Heterozygous

A
  • different alleles of same gene

- Aa

35
Q

Hemizygous

A
  • one single copy of a gene instead of two

- male has XY sex chromosome -> hemizygous

36
Q

Genetic Family Pedigree

A
  • if phenotype “skips” generations -> be suspicious of an autosomal recessive disorder
  • if no “skip” then most likely autosomal dominant.
  • be suspicious for x-linked recessive - > if a father doesn’t have the phenotype then none of his daughters display it

DAT Biology (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions