Human Chromosomes and Disorders

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Questions and Answers

What is the total number of chromosomes in a typical human?

46 (correct)

A karyotype is used to identify chromosomal abnormalities.

True

What are the two categories of chromosomes in humans?

Sex chromosomes and autosomes

A karyotype is an organized display of an individual's __________ arranged in pairs.

chromosomes Signup and view all the answers

Match the following terms with their descriptions:

Karyotype = An organized display of chromosomes Autosomes = Non-sex chromosomes Sex chromosomes = Determine the gender of an individual Monohybrid cross = Study of one trait inheritance Signup and view all the answers

What is the purpose of using a hypotonic solution in a blood culture?

To make the white blood cells swell Signup and view all the answers

All sperm cells carry an X chromosome.

False Signup and view all the answers

What is the genetic composition of women?

XX Signup and view all the answers

Nondisjunction occurs when chromosomes or chromatids fail to _____ during meiosis.

separate Signup and view all the answers

Match the following terms with their definitions:

Centromere = Region where sister chromatids are joined Sister chromatids = Identical copies of a chromosome Homologous chromosomes = Pair of chromosomes containing the same genes Pay of sex chromosomes = Chromosomes determining the sex of an organism Signup and view all the answers

What type of chromosomes are present in the offspring of a male and female with genetic composition XY and XX?

XX and XY chromosomes Signup and view all the answers

Centrifugation is used to separate blood cells based on their density.

True Signup and view all the answers

What chromosomal disorder is characterized by an extra chromosome 21?

Down Syndrome Signup and view all the answers

What is the genetic condition associated with trisomy of chromosome 21?

Down Syndrome Signup and view all the answers

Klinefelter's Syndrome is a condition that typically affects females.

False Signup and view all the answers

What affect does Down Syndrome typically have on individuals?

Mild to severe mental learning disabilities. Signup and view all the answers

Individuals with Turner's Syndrome are typically _____ due to having only one X chromosome.

sterile Signup and view all the answers

Match the following trisomy disorders with their corresponding chromosome number:

Down Syndrome = Trisomy 21 Patau Syndrome = Trisomy 13 Edward's Syndrome = Trisomy 18 Signup and view all the answers

How many individuals out of 800 are estimated to be affected by Down Syndrome?

1 in 800 Signup and view all the answers

All individuals born without an X chromosome have been documented in medical literature.

False Signup and view all the answers

What is the condition characterized by a male having multiple X chromosomes and one Y chromosome?

Klinefelter's Syndrome Signup and view all the answers

Study Notes

Human Chromosomes

Humans have 46 chromosomes total
2 sex chromosomes - X and Y
44 autosomes - Non-sex chromosomes

Karyotype

Karyotype is a visual representation of an individual's chromosomes.
Chromosomes are arranged in pairs from largest to smallest.
Helps identify potential chromosomal abnormalities, like Down syndrome

Sex Determination

Females have 2 X chromosomes (XX)
Males have 1 X and 1 Y chromosome (XY)
Sex is determined by the sperm cell, as it can carry either an X or Y chromosome.

Chromosomal Disorders

Nondisjunction is when chromosomes don't separate correctly during meiosis.
Trisomy refers to having 3 copies of a chromosome instead of 2.
Examples of trisomy disorders include Down syndrome, Patau syndrome, and Edward's syndrome.

Down Syndrome

Trisomy 21 (3 copies of chromosome 21)
Affects about 1 in 800 babies
Causes varying degrees of mental disabilities, increased susceptibility to illnesses, and birth defects.

Other Trisomy Disorders

Patau syndrome (trisomy 13)
Edward's syndrome (trisomy 18)

Sex Chromosome Disorders

Turner's syndrome - Females with one X chromosome, often sterile.
Klinefelter's syndrome - Males with multiple X chromosomes & one Y chromosome, usually sterile.
XYY - Males with extra Y chromosome
No recorded instances of individuals born without an X chromosome.

Evolutionary Connection: Y Chromosome

Y chromosomes are passed directly from father to son, with very minimal changes.
Mutations in the Y chromosome can reveal information about shared ancestry.
Analysis of Y chromosomes in Central Asia revealed a common ancestor for about 8% of males in the region, traced back to Genghis Khan about 1000 years ago.

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Description

Explore the intricacies of human chromosomes, karyotypes, and the mechanisms of sex determination. This quiz covers key chromosomal disorders, including Down syndrome and its implications. Test your knowledge on genetic abnormalities and their effects.