Chromatin, Mitosis, and Genetic Material Organization Quiz

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Questions and Answers

During which stage of meiosis do sister chromatids move to opposite poles?

Metaphase II

Anaphase II (correct)

Prophase I

Telophase II

What is the result of crossing over between two non-sister chromatids of homologous pairs?

Homologous chromosomes have only paternal genes

Homologous chromosomes have only maternal genes

Individual chromosomes have both paternal and maternal genes (correct)

Sister chromatids are identical

How many diploid combinations are possible due to independent assortment in humans?

8.4 million

70 trillion (correct)

4,096

What is the term for the process by which homologous pairs line up randomly during metaphase I?

Independent assortment (C) Signup and view all the answers

Which stage of meiosis follows Anaphase II?

Telophase II (D) Signup and view all the answers

What is the approximate number of possible gamete combinations due to independent assortment in humans?

8.4 million (C) Signup and view all the answers

What is the primary function of histone proteins in the organization of genetic material?

To act as spools for DNA wrapping (C) Signup and view all the answers

What is the term for the thread-like structures that form during cell division?

Chromatin (B) Signup and view all the answers

What is the term for the number of chromosomes present in a species?

Karyotype (D) Signup and view all the answers

What is the region known as, where chromosomes pinch in during cell division?

Centromere (D) Signup and view all the answers

What is the term for the study of the number and structure of chromosomes in a species?

Cytogenetics (A) Signup and view all the answers

What is the term for the genetic information stored in DNA?

Genome (C) Signup and view all the answers

What is the result of nondisjunction of sex chromosomes in females?

Turner Syndrome (XO) (B) Signup and view all the answers

What is the purpose of chorion villus sampling?

To detect chromosomal disorders (D) Signup and view all the answers

During which phase of meiosis is genetic variation introduced?

Prophase I and Metaphase I (B) Signup and view all the answers

What is the purpose of amniocentesis?

To detect chromosomal disorders (D) Signup and view all the answers

What is the result of nondisjunction of sex chromosomes in males?

Klinefelter Syndrome (XXY) (A) Signup and view all the answers

What is the incidence of XXX Females?

1:1000 (B) Signup and view all the answers

Study Notes

Chromosomal Abnormalities

Turner Syndrome (XO): underdeveloped female sex characteristics
Klinefelter Syndrome (XXY Males): high levels of female sex hormones; more developed female sex characteristics; sterile
Jacobs Syndrome (XYY Males): somewhat taller; below average intelligence
XXX Females (1:1000 live births): healthy and fertile; karyotype determines

Prenatal Screening for Genetic Disorders

Chorion Villus Sampling (Biopsy): cells from the outer membrane of the embryo are removed for karyotyping to detect chromosomal disorders; can be done as early as 8 weeks into pregnancy
Amniocentesis: amniotic fluid containing cells from the fetus is drawn to prepare and analyze karyotypes for chromosomal abnormalities

Mitosis and Meiosis

Genetic variation is introduced during Prophase I and Metaphase I
Chromatin condenses into visible chromosomes during cell division
Histones act as spool, wrapping DNA to fit in the nucleus
Chromosome = DNA and associated proteins
Centromere: the pinched region on a chromosome

Organization of Genetic Material

Genetic information is stored in DNA (deoxyribonucleic acid)
Chromosomes are found in the nucleus
Histones wrap DNA, allowing it to fit in the nucleus

Chromosome Number

Humans have 46 chromosomes: 22 pairs of homologous chromosomes (autosomes) and 2 sex chromosomes (XX or XY)
Different species have different numbers of chromosomes

Alleles and Homologous Chromosomes

Homologous chromosomes carry the same genes at the same location (locus)
Alleles: different "flavors" of the same gene
Each side's microtubules on a kinetochore of one replicated chromosome separate during Anaphase II

Meiosis

Meiosis results in genetically distinct daughter cells
Crossing over: occurs between two non-sister chromatids of homologous pairs
Independent assortment: occurs in Metaphase I, where homologous pairs line up randomly
Random fertilization: 2 gametes combine, resulting in 70 trillion diploid combinations with crossing over

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Description

Test your knowledge on cell division, chromatin, mitosis, and the organization of genetic material in cells. Learn about the history of these concepts and the structure and function of chromosomes and DNA.