Genetics Mastery Quiz: Unraveling the Code of Heredity

1. The purpose of meiosis is to form haploid gametes or sex cells.

True

False

Meiosis halves the chromosome number, producing haploid gametes necessary for sexual reproduction.

Explanation

Meiosis halves the chromosome number, producing haploid gametes necessary for sexual reproduction.

2. Heredity is the study of the passing of traits from one generation to another.

True

False

Heredity examines how traits are transmitted from parents to offspring through genetic information.

Explanation

Heredity examines how traits are transmitted from parents to offspring through genetic information.

3. Which Punnett square represents a cross between two heterozygous genotypes?

Aa x aa

AA x Aa

Aa x Aa

AA x AA

Aa x Aa: In this cross, both parents have a heterozygous genotype, resulting in a 3:1 phenotypic ratio.

Explanation

Aa x Aa: In this cross, both parents have a heterozygous genotype, resulting in a 3:1 phenotypic ratio.

4. Mitosis results in four daughter cells with identical DNA.

True

False

Mitosis results in two identical daughter cells, maintaining the chromosome number. It produces two genetically identical daughter cells; meiosis produces four genetically varied cells.

Explanation

Mitosis results in two identical daughter cells, maintaining the chromosome number. It produces two genetically identical daughter cells; meiosis produces four genetically varied cells.

5. A purebred organism is homozygous for either the dominant or recessive allele of a gene

True

False

Purebred organisms have identical alleles for a particular trait, either homozygous dominant or homozygous recessive.

Explanation

Purebred organisms have identical alleles for a particular trait, either homozygous dominant or homozygous recessive.

6. Sex-linked traits are determined by genes located on sex chromosomes.

True

False

Genes for sex-linked traits are located on the sex chromosomes, usually the X chromosome.

Explanation

Genes for sex-linked traits are located on the sex chromosomes, usually the X chromosome.

7. Which Punnett square crosses two heterozygous individuals?

AA x aa

Aa x aa

Aa x Aa

AA x Aa

Aa x Aa: This cross involves individuals with a heterozygous genotype, resulting in a 3:1 phenotypic ratio.

Explanation

Aa x Aa: This cross involves individuals with a heterozygous genotype, resulting in a 3:1 phenotypic ratio.

8. A section of DNA that codes for a particular protein is a(n)

Gene

Chromosome

Autosome

Chromatid

Genes are segments of DNA that contain the instructions for building proteins, serving as the basic units of heredity.

Explanation

Genes are segments of DNA that contain the instructions for building proteins, serving as the basic units of heredity.

9. If the gene for a sex-linked trait is located on an X chromosome, then only females will exhibit the trait.

True

False

Both males and females can exhibit sex-linked traits, as males inherit one X chromosome from their mothers.

Explanation

Both males and females can exhibit sex-linked traits, as males inherit one X chromosome from their mothers.

10. What is the relationship between DNA and chromosomes?

Chromosomes are made of DNA.

Chromosomes code for DNA

DNA codes for chromosomes

DNA is made of chromosomes

Chromosomes are made of DNA: Chromosomes are composed of DNA and proteins, carrying genetic information.

Explanation

Chromosomes are made of DNA: Chromosomes are composed of DNA and proteins, carrying genetic information.

11. Which Punnett square crosses a heterozygous individual with a homozygous recessive individual?

AA x Aa

Aa x aa

Aa x Aa

Aa x aa

Aa x aa: This cross examines the offspring when a heterozygous individual mates with one homozygous recessive for a specific trait.

Explanation

Aa x aa: This cross examines the offspring when a heterozygous individual mates with one homozygous recessive for a specific trait.

12. The combination of alleles that constitute an organism's genetic makeup is that organism's phenotype.

True

False

It is a false statement. The combination of alleles constitutes the genotype. The phenotype results from the expression of alleles and the environment, determining the organism's observable traits.

Explanation

It is a false statement. The combination of alleles constitutes the genotype. The phenotype results from the expression of alleles and the environment, determining the organism's observable traits.

13. Which cross will have the lowest likelihood of tall offspring?

Tt x Tt

Tt x tt

TT x Tt

Tt x tt

In this cross (D), both parents carry the recessive allele, resulting in offspring with a high likelihood of being short.

Explanation

In this cross (D), both parents carry the recessive allele, resulting in offspring with a high likelihood of being short.

14. Which of the following best describes what happens during independent assortment?

Alleles are passed down from parents to offspring.

Alleles are expressed as traits.

Alleles are mixed and matched in gametes.

All of the above

Alleles are mixed and matched in gametes: Independent assortment occurs during meiosis, where alleles for different traits segregate independently into gametes, creating genetic diversity.

Explanation

Alleles are mixed and matched in gametes: Independent assortment occurs during meiosis, where alleles for different traits segregate independently into gametes, creating genetic diversity.

15. Unlike sex chromosomes, autosomes do not

Occur in pairs in the nucleus

Contain DNA

Code for proteins

Determine the sex of an organism

Occur in pairs in the nucleus: Sex chromosomes determine an individual's sex, occurring in pairs, while autosomes do not play a role in sex determination. Autosomes do not determine an organism’s sex. They come in homologous pairs and carry genes unrelated to sex determination.

Explanation

Occur in pairs in the nucleus: Sex chromosomes determine an individual's sex, occurring in pairs, while autosomes do not play a role in sex determination. Autosomes do not determine an organism’s sex. They come in homologous pairs and carry genes unrelated to sex determination.