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Mbg 2040 > Lecture 6-8 > Flashcards

Lecture 6-8 Flashcards

1
Q

Most plants and animals are what configuration of chromosome

A

diploid

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2
Q

What is monoploidy

A

only one set of chromosomes (not pairs like humans)

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3
Q

What is polyploidy

A

more than normal set of chromosomes (ie. triploidy, tetraploidy, etc.)

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4
Q

Why is it beneficial for plants to be polyploidy

A

more genetic material = larger and stronger

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5
Q

What are autopolyploids

A

all chromosome sets are identical

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6
Q

What are the observable traits of autopolyploidy

A

more vegetative growth and less seed production

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7
Q

How does autopolyploidy occur through mitosis

A

diploid 2n goes through replication but cytokinesis fails and no cell division occurs, resulting in a tetraploid 4n cell

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8
Q

How does autopolyploidy occur in meiosis

A

cytokinesis of 1 of 2 daughter cells in meiosis 2 fails, creating a 2n and a 1n that combine to form a triploid

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9
Q

What is the problem with polyploidy

A

many polyploids are sterile due to problems with pairing and separation of homologous chromosomes in meiosis

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10
Q

Does a plant still have reproductive efforts even if its sterile

A

yes, just unsuccessful efforts

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11
Q

What occurs in meiosis 1 to make it non viable in many polyploids

A

gametes end up with random variation of talents, making them non viable so they die

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12
Q

If you have a 3n=33 polyploid plant trying to reproduce, what would be observed in metaphase 1 and anaphase 1

A

sister chromatid pairs are pulled to poles randomly, resulting in univalents, bivalents, or trivalents depending on the separation

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13
Q

If a 3n=33 plant undergoes meiosis attempts and 2 homologous chromosomes pair while the other does not pair at all, what is observed

A

11 bivalents and 11 univalents (to make 3n=33)

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14
Q

If a 3n=33 plant undergoes meiosis attempts and all homologous chromosomes pair up, what is observed

A

11 trivalents (to make 3n=33)

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15
Q

If a 3n=33 plant undergoes meiosis attempts and no homologous chromosomes pair up, what is obersved

A

33 univalents

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16
Q

In a 3n=33 organism, how many segregation options are there

A

11 options

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17
Q

What are allopolyploids

A

polyploids as a result of crossing between 2 or more species

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18
Q

What type of reproduction is done to produce allopolyploids

A

asexual (mitosis)

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19
Q

Why can’t sexual reproduction occur between plant A and plant B

A

chromosome sets from A and B are not homologous to one another

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20
Q

What occurs spontaneously in plant chromosomes

A

can double their chromosomes spontaneously

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21
Q

What is an amphidiploid

A

a plant originating from hybridization between 2 plant species in which the chromosome number is the sum of the 2 parental chromosome numbers

22
Q

How would a sterile animal be formed

A

interspecies crosses (polyploidy)

23
Q

What is an example of polyploidy in animals resulting in a sterile animal

A

donkey x horse = mule

24
Q

What is aneuploidy

A

diploid genome that lacks a chromosome or carries an extra

25
Q

what is the term for a 2n + 1

A

triploidy

26
Q

what is the term for a 2n-1

A

monoploidy

27
Q

What is the result of non disjunction in meiosis 1

A

1 daughter cell gets no chromosomes, one daughter cell gets all chromosomes
- once in meiosis 2 the cell with chromosomes further divides, while the other produces empty daughter cells
(results in 2 trisomic and 2 monosomic cells when fertilized)

28
Q

What is the result of non disjunction in meiosis 2

A

normal division occurs in meiosis 1, however in meiosis 2 one of the cells separates incorrectly, creating an empty daughter cell and a daughter cell with an extra chromosome
(results in a trisomic chromosome and monosomic chromosome, and 2 normal diploids)

29
Q

What happens to autosomal monosomies in humans

A

lost early in pregnancy (never seen as live births)

30
Q

What happens to autosomal trisomies in humans

A

only 1 type of trisomy occurs that results in life into adulthood - Down syndrome
rest usually die by age 2-3 due to genetic defect

31
Q

What is the only fully viable human trisomy

A

chromsome 21 - Down syndrome

32
Q

What is the gamete configuration of Turner syndrome

A

X0

33
Q

What is the gamete configuration of Kleinfelter syndrome

A

XXY

34
Q

What is the gamete configuration of triple x syndrome

A

XXX

35
Q

What is the gamete configuration of double y males

A

XYY

36
Q

How are Turner syndrome, Klinefelter syndrome, and triple x syndrome tolerated

A

x inactivation

37
Q

How is double y male syndrome tolerated

A

Y chromosomes are small and usually only carry hormones, so little effect on humans as a whole

38
Q

If a diploid has a 2n=36 configuration, how many chromosomes would be present in a monosomic member of this species

A

2n - 1, so 35 chromosomes would be observed in this specific species

39
Q

How does age of mother impact risk of trisomy and monosomy

A

as age increases of mother, risk of trisomy or monosomy also increases

40
Q

Why does age play a role in risk of trisomy or monosomy

A

exchange of genetic material occurs constantly as eggs are arrested in prophase 1, with more exchange of this material (more time aged) the likelihood of mitotic spindle separation decreases which results in higher risk for non disjunction

41
Q

What, other than age, has been found to impact trisomy and monosomy risk

A

chemicals (environment)

42
Q

What is a deletion/deficiency

A

missing chromosome segment

43
Q

What is a duplication

A

extra chromosome segment

44
Q

What is hypoploidy

A

hypo = less
less genetic material as a result of deletion or deficiency

45
Q

What is hyperploidy

A

hyper = more
more genetic material as a result of duplication (or gain of an entire chromosome)

46
Q

What is translocation

A

when a segment from one chromosome is detached and reattached to a different (non homologous) chromosome

47
Q

What is reciprocal translocation

A

pieces of two non-homologous chromosomes are exchanged without any net loss of genetic material

48
Q

What are compound chromosomes

A

formed by the fusion of homologous chromosomes, sister chromatids, or homologous chromosome segments

49
Q

What are Robertsonian translocations

A

formed by the fusion of 2 non homologous chromosomes at their centromeres

50
Q

How can a translocation lead to cancer

A

if moved to a chromosome that cannot regulate it, replication will occur out of hand and cause mutations (cancer)

51
Q
A

Mbg 2040 (13 decks)

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