Brainscape's Knowledge GenomeTM

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


See full index

BIOL214 > chapter 13 > Flashcards

chapter 13 Flashcards

1
Q

chromosomal theory of inheritance

A

walter sutton (1902) - based on observations that similar chromosomes paired with one another during meiosis

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

carl correns

A

1900 - first suggested central role for chromosomes
- authored one of the scientific papers announcing rediscovery of Mendel’s work

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

inheritance of eye color in fruit flies

A

T.H. Morgan (1910) - working with fruit fly (Drosophila melanogaster)
- discovered a mutant male fly with white eyes instead of red
- crossed the mutant male to a normal red-eyed female
-> all F1 progeny were red eyed = dominant trait

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

inheritance of eye color in fruit flies (Morgan)

A
  • crossed F1 females and F1 males
  • F2 generation contained red and white-eyed flies
    *all white eyed flies were male
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

X-chromosome

A
  • test cross of a F1 female with a white eyed male showed the viability of white eyed females

conclusion: eye color gene resides on the female X chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

sex-chromosomes

A

a pair of dissimilar chromosomes that still that still pair during meiosis and mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

drosophila sex determination

A

based on number of x chromosomes
- 2 X chromosomes = female
- 1 X and 1 Y chromosome = male

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

birds sex determination

A

ZZ = male
ZW = female

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

insects (grasshoppers) sex determination

A

XX = female
XO = male (O indicates absence of chromosome)

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

honeybees sex determination

A

diploid = female
haploid = male

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

sex chromosomes in humans

A

46 total chromosomes
- 22 pairs are autosomes; 1 pair are chromosomes
- Y chromosomes = highly condensed (recessive alleles on male X’s have no active counterpart on Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

autosomes

A

non-sex chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

SRY gene

A

default sex is female; requires SRY gene on Y for maleness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

sex-linkage

A
  • in XY sex-determination organisms, few genes from the Y chromosome are expressed
  • recessive alleles have no active partner on Y so a single recessive sex-linked gene can produce recessive phenotype

ex: hemophilia, red-green color blindness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

dosage compensation

A
  • ensures equal expression of genes from sex chromosomes (even tho # of chromosomes is different between sexes)
  • in mammalian female cells, 1 X chromosome is randomly inactivated and condensed into a Barr body
  • females heterozygous for genes on the X chromosomes are genetic mosaics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

female genetic mosaics

A

Calico cat
- allele for black fur is inactivated some places; allele for orange fur is inactivated in others; second gene causes patchy discrimination of pigment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

chromosome theory exceptions

A

mitochondria + chloroplasts contain genes
- traits controlled by these genes do not follow the chromosomal theory of inheritance
- genes from mitochondria and chloroplasts are often passed to offspring by one parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

maternal inheritance

A

genes from mitochondria and chloroplasts are often passed to offspring by one parent, usually mother

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

plant maternal inheritance

A

in plants, chloroplasts are often inherited from the mother (species dependent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

genetic mapping

A

distance between genes on a chromosome could be estimated based on genetic recombination(crossing over) patterns between genes
- if crossover occurs, parental alleles are recombined producing recombinant gametes

21
Q

Creighton and McClintock experiment hypothesis

A

crossing over involves a physical exchange of genetic material

22
Q

Creighton and McClintock experiment prediction

A

recombination of visible differences in a chromosome should correlate with genetic recombination of alleles

23
Q

Creighton and McClintock experiment test

A

using two visible chromosome markers (yellow extension marker and green knob marker) combined with two genetic markers (kernel color and kernel texture)

24
Q

Creighton and McClintock experiment result

A

genetically recombinant progeny also have physically recombinant chromosomes

25
Q

Creighton and McClintock experiment conclusion

A

a physical exchange of genetic material accompanied with genetic recombination

26
Q

T.H. Morgan

A

observed that recombinant progeny reflected relevant location of genes

27
Q

Alfred Sturtevant

A

put Morgan’s observation in quantitative terms
- as physical distance on chromosome increases, so does the probability of recombination (crossover) occurring between gene loci

28
Q

constructing genetic maps

A

1% recombination = 1 map unit (m.u.)
1 map unit = 1 centiMorgan (cM)

*the distance between genes is proportional to the frequency of recombination events

29
Q

multiple crossovers

A

-if homologues undergo 2 crossovers between gene loci, the parental recombination is restored (leads to an underestimate of true genetic distance)

  • odd #’s of crossover events (1,3, etc) produce recombinant gametes
  • no crossover or even numbers produce parental gametes
  • relationship between true distance on a chromosome and recombination frequency is not linear
30
Q

3 point testcross

A
  • use 3 loci instead of 2 to construct maps
  • middle gene allows tracking of recombination events
  • in any 3 pt cross, the offspring with 2 crossovers is the least frequent class
  • geneticists use 3 pt crosses to determine the order of genes, then use data from closest two point crosses to determine distance
31
Q

dominant/recessive inheritance

A
  • some human traits are controlled by a single gene; some of which show dominant/recessive inheritance

ex: dominant pedigree - juvenile glaucoma; recessive pedigree - albinism

32
Q

hereditary juvenile glaucoma

A
  • causes degeneration of optic nerve leading to blindness
  • dominant trait appears every generation
33
Q

albinism

A
  • when pigment melanin is not produced; due to nonfunctional allele of enzyme tyrosinase
  • males and females affected equally
  • most unaffected individuals have unaffected parents
34
Q

sex-linked human genetic disorders

A

some affect males more than females

35
Q

hemophilia

A

affect a protein in a cascade involved in formation of blood clots
- caused by an X-linked recessive allele
- heterozygous females are asymptomatic carriers

36
Q

human genetic disorder causes

A

a single amino acid change in a single protein can result in clinical syndrome
- sickle cell anemia: caused by defect in hemoglobin (oxygen carrier molecule)
- leads to impaired oxygen delivery to tissues

37
Q

sickle cell anemia

A

-homozygotes for sickle cell allele exhibit intermittent illness and reduced life span
- heterozygotes appear normal but have hemoglobin with reduced ability
- confers resistance to blood-borne parasite that causes malaria, explains higher proportion of allele

38
Q

nondisjunction

A

failure of homologues or sister chromatids to separate properly during meiosis

*changes chromosome number

39
Q

aneuploidy

A

result of nondisjunction; gain/loss of a chromosome
- in all but a few cases, they do not survive

40
Q

monosomy

A

loss of a chromosome

41
Q

trisomy

A

gain of a chromosome

42
Q

nondisjunction of autosomes

A

embryos trisomic for 5 of the smallest autosome can survive birth
13,15,18 - severe defects, die within a few months
21,22 - can survive to adulthood

43
Q

down syndrome

A

trisomy 21
- can be a full, third 21st chromosome
- can be a translocation of a part of chromosome 21
- mother’s age influences risk

44
Q

nondisjunction of sex chromosomes

A
  • do not generally experience severe developmental abnormalities
  • individuals have somewhat abnormal features, but often reach maturity and in some cases can be fertile
45
Q

XXX

A

triple X syndrome

46
Q

XXY

A

Klinefelter syndrome (males)

47
Q

XO

A

Turner syndrome (females)

48
Q

OY

A

nonviable zygotes

49
Q

XYY

A

Jacob syndrome (XYY)

BIOL214 (4 decks)

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