Chapter 13 - Modern Understanding Of Inheritance Flashcards

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1
Q

What type of genes disrupted mendels model?

A

Linked genes (genes in the same chromosome) especially if they are close together

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2
Q

How does recombination frequency work?

A

Genes that linked perfectly (very close together on the chromosome) have a recombination frequency of 0, while those that are perfectly unlinked (far apart in the chromosome or on different chromosomes) had a recombination frequency of 100

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3
Q

What disorders occur when chromosomes behave abnormally? What are the two types called?

A

Congenital disorders

1- structural rearrangements
2- abnormalities in chromosome number

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4
Q

What is a karyotype and karyogram?

A

A procedure to see the arrangements and characteristics of all 23 of your chromosomes which is shown in the karyogram

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5
Q

What is the size arrangement of autosomes?

A

1-22 is largest to smallest, except 21 is shorter than 22

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6
Q

What are the long and short arms called in a chromosome?

A

Long arms are q and short arms are p

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7
Q

How does nondisjunction occur?

A

It occurs during meiosis when homologous chromosomes or sister chromatids fail to separate due to misalignment or incomplete synapsis or spindle apparatus dysfunction

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8
Q

Individuals with the proper number of chromosomes for that species are called…; while those with an error in chromosome number are called what?

A

Correct is euploid, incorrect is aneuploid

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9
Q

What is monosomy?

A

Losing one chromosome, happens if the zygote is missing an autosome or development fails

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10
Q

What is trisomy?

A

Gaining an extra chromosome, these zygotes may develop offsprings that can live a long time. But excess gene dosage results in many functional and developmental difficulties due to excess gene products

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11
Q

What is the most common trisomy?

A

Trisomy 21

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12
Q

What is polyploidy? Where is it seen?

A

Individuals with more than the correct number of chromosome sets

Common in plants, but rare in animals

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13
Q

What does triploid zygotes result from?

A

An abnormal diploid sperm fertilizing a normal haploid egg

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14
Q

Sex chromosome nondisjunction in humans is relatively mild due to what?

A

X inactivation in female embryos where one X chromosome condenses into a quiescent structure called a Barr body, females can compensate for this loss of an X chromosome via dosage compensation, that is the remaining X chromosome is hyperactive and the Barr body can express a few genes usually involved in ovary and brain development

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15
Q

What do individuals carrying abnormal numbers of X chromosomes do?

A

Inactivate all but one X chromosome in each cell

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16
Q

XXX individuals are phenotypically what sex? What happens to them

A

Female, but experience developmental delays and reduced fertility

17
Q

XXY individuals are usually what sex? And what effects does it have?

A

Male, but have small testes, enlarged breasts, and reduced body hair

18
Q

What is the presentation in chromosomes of Klinefelter syndrome?

A

Individuals would have Y chromosome and up to 5 X chromosomes, the extra X chromosomes become Barr bodies

19
Q

What happens with individuals with only an X chromosome? What is it called?

A

They have a female genotype with short stature, webbed skin in neck, hearing and cardiac impairments, and sterility. It is called turners syndrome

20
Q

What is the cause of cri-du-chat syndrome?

A

Deletion of most or all of 5p (the small arm)