Questions and Answers
When a chromosome breaks it is referred to as a?
Select all of the environmental agents that can cause chromosomal mutations. (Select all that apply)
Inversions, translocations, deletions, and duplications are types of chromosomal _____
mutations
A deletion is a loss of a segment of a(n) _____
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If a chromosome started out with the following gene sequence (ABCDEFG) and ended up with this sequence (ABCDEDEFG), which of the following took place?
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An inversion occurs when a segment of _____ is turned 180 degrees.
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Normally, humans have _____ pairs of autosomes.
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X and Y chromosomes are classified as?
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A gene located on an X or Y chromosome is said to be?
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A male who has color blindness (XbY) mates with a carrier female (XBXb). What percentage of their male children will be color blind?
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A female that is heterozygous for an X-linked recessive trait?
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A karyotype is?
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Humans normally have 22 pairs of _____ and one pair of _____ chromosomes.
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Gametes with extra or missing chromosomes are the result of?
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In humans, a _____ condition results when one gamete has 24 chromosomes and is united with a normal gamete having 23.
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Select all the ways in which monosomy can occur. (Select all that apply)
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If a human sperm has 22 chromosomes in it and fertilizes an egg with 23, the resulting condition is referred to as a _____ condition.
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The most common autosomal trisomy is?
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A Barr body is a(n)?
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Select all of the examples of conditions that are changes in sex chromosome number. (Select all that apply)
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Females with more than two X chromosomes are called a(n) _____ -X female and tend to have few phenotypic distinctions besides being tall and thin.
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Taller than average males with persistent acne, speech and reading problems likely have an extra _____ chromosome and a condition called Jacobs syndrome.
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Viruses, organic chemicals, and radiation are examples of agents that can cause chromosomal _____
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In humans, a _____ condition occurs when a gamete that has 22 chromosomes unites with a gamete with 23.
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Match the chromosome composition with its correct syndrome:
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Match the condition of the left with the symptom on the right:
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Study Notes
Chromosomal Mutations
- Chromosomal breakage leads to chromosomal mutations.
- Types of chromosomal mutations include inversions, translocations, deletions, and duplications.
Environmental Agents
- Organic chemicals, radiation, and viruses can cause chromosomal mutations.
- Maternal and paternal age may contribute to mutation risk.
Types of Chromosomal Changes
- A deletion results in a loss of a chromosome segment.
- An inversion involves a 180-degree turn of a chromosome segment.
- Duplication occurs when a gene sequence is repeated (e.g., ABCDE becomes ABCDEDE).
Human Chromosomes
- Humans have 22 pairs of autosomes and one pair of sex chromosomes (X and Y).
- Sex-linked genes are located on X or Y chromosomes.
Color Blindness Inheritance
- In a cross between a color-blind male (XbY) and a carrier female (XBXb), 50% of their male children will be color blind.
- A heterozygous female for an X-linked recessive trait is a carrier but typically not affected.
Karyotypes and Chromosome Inspection
- A karyotype provides a visual inspection of chromosomes, used to identify chromosomal abnormalities.
Gametes and Chromosomal Conditions
- Nondisjunction causes gametes to have extra or missing chromosomes.
- Monosomy occurs when a gamete with 22 chromosomes unites with a normal gamete of 23 chromosomes, resulting in a single copy of a chromosome.
Trisomies and Syndromes
- The most common autosomal trisomy is Trisomy 21, also known as Down syndrome.
- A Barr body is an inactivated X chromosome found in females.
- Conditions with altered sex chromosome numbers include Turner syndrome, Klinefelter syndrome, Jacobs syndrome, and Poly-X female.
Genetic Conditions
- Females with more than two X chromosomes are called Poly-X females, typically exhibiting few notable phenotypes.
- Males with an extra Y chromosome may have Jacobs syndrome, characterized by height and acne issues.
Recap on Chromosomal Mutations
- Viruses, organic chemicals, and radiation are critical agents that induce chromosomal mutations.
- A gamete with 22 chromosomes fertilizing one with 23 results in a monosomy condition.
Chromosomal Syndrome Associations
- XXX corresponds to Poly-X syndrome.
- XXY or XXXY is linked to Klinefelter syndrome.
- XYY indicates Jacobs syndrome.
- A single X chromosome denotes Turner syndrome.
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Description
Test your knowledge on the chromosomal basis of inheritance with these flashcards. This quiz covers key concepts such as chromosomal mutations and environmental agents that can cause these mutations. Perfect for students studying Biology Chapter 24!
