BIO 104 - General Biology II Exam 1 Review

Questions and Answers

What defines heredity in biological terms?

The ability to produce both eggs and sperm in the same individual

The scientific study of heredity and inherited variation

The formation of a zygote from two gametes

The transmission of traits from one generation to the next (correct)

Which statement accurately describes homologous chromosomes?

Chromosomes that always come from one parent

Chromosomes that only appear in gametes

Chromosomes that have the same length, pattern, and centromere position and carry genes (correct)

Chromosomes identical in DNA sequence and length

What term describes the genetic composition of an organism's sex chromosomes?

Autosomes

Maternal chromosomes

Homologous chromosomes

Sex chromosomes (correct)

What type of reproduction involves the fusion of gametes?

Sexual reproduction Signup and view all the answers

What is true about diploid cells?

They contain two sets of every chromosome Signup and view all the answers

What is the definition of a dominant allele?

A gene variation that expresses a phenotype even when paired with a recessive allele. Signup and view all the answers

What does the term 'phenotype' refer to?

The observable physical traits of an organism. Signup and view all the answers

Which of the following accurately describes the F2 Generation?

The offspring resulting from self or cross-pollination of the F1 Generation. Signup and view all the answers

In which inheritance pattern do two alleles influence the phenotype in distinct ways?

Co-dominance Signup and view all the answers

Which statement best expresses the concept of complete dominance?

A dominant allele masks the effect of a recessive allele. Signup and view all the answers

What characterizes polygenic inheritance?

Many genes independently influence a single trait. Signup and view all the answers

What does 'true breeding' refer to in genetics?

Organisms that consistently pass down specific traits to their offspring. Signup and view all the answers

What is the main role of the synaptonemal complex during meiosis?

To facilitate the exchange of genetic material between homologous chromosomes. Signup and view all the answers

What distinguishes haploid cells from diploid cells?

Haploid cells contain just one set of chromosomes. Signup and view all the answers

What are the sex chromosomes that a male contributes to his offspring?

X or Y chromosomes. Signup and view all the answers

How many pairs of homologous chromosomes do humans have?

23 pairs. Signup and view all the answers

What is the defining characteristic of homologous chromosomes?

They have the same length and carry the same genes. Signup and view all the answers

In a karyotype, how can one determine if the individual is female?

By noting two similar chromosomes in the 23rd pair. Signup and view all the answers

What is true regarding gametes in humans?

Gametes are haploid cells. Signup and view all the answers

Which of the following accurately describes a sister chromatid?

They are identical copies of a chromosome linked at the centromere. Signup and view all the answers

Which of the following statements is correct about sexual reproduction and hermaphroditism?

They require fertilization of gametes to produce offspring. Signup and view all the answers

What is the main outcome of mitosis?

Two identical daughter cells Signup and view all the answers

Which event occurs during Prophase I of Meiosis?

Crossing over Signup and view all the answers

What is the definition of independent assortment of chromosomes?

Homologous chromosomes separate independently. Signup and view all the answers

What is a characteristic unique to meiosis?

Crossing over between homologous chromosomes Signup and view all the answers

What describes the alternation of generations in an organism?

Alternating between diploid and haploid stages Signup and view all the answers

What is the role of DNA replication during Interphase prior to meiosis?

To ensure each daughter cell receives a complete set of chromosomes Signup and view all the answers

Which mechanism does NOT contribute to genetic variation?

Mitosis Signup and view all the answers

What was one reason pea plants were a suitable study organism for Mendel?

They have many observable traits Signup and view all the answers

Study Notes

Key Definitions in Genetics

Heredity: Transmission of traits from one generation to the next.
Variation: Differences in appearance among offspring compared to parents and siblings.
Genetics: Scientific study of heredity and inherited variation.
Genes: Units of heredity made up of DNA segments.
Gametes: Reproductive cells (sperm and egg) that carry genes to the next generation.
Locus: Specific position of a gene on a chromosome.
Asexual Reproduction: Reproduction without sperm and egg involvement, resulting in clones.
Hermaphroditism: Ability to produce both eggs and sperm within the same individual.
Sexual Reproduction: Offspring produced from two parents.
Karyotype: Ordered display of chromosome pairs from a cell.
Homologous Chromosomes: Chromosomes similar in size, shape, and gene positions.
Autosomes: 22 pairs of chromosomes excluding sex chromosomes.
Diploid Cell: Cell with two sets of chromosomes (46 in humans).
Haploid Cell: Cell with one set of chromosomes (23 in humans).

Gametes and Fertilization

Fertilization: Fusion of male sperm and female egg to form a zygote (fertilized egg).
Zygote: Cell formed post-fertilization containing genetic material from both parents.

Genetic Terminology

Phenotype: Observable physical traits of an organism.
Genotype: Genetic makeup of an organism.
Dominant Allele: Produces a certain phenotype even in presence of other alleles.
Recessive Allele: Phenotype expressed only when two recessive alleles are present.

Genetic Crosses and Inheritance Patterns

Monohybrid Cross: Cross between organisms focusing on one trait.
Dihybrid Cross: Cross considering two traits and their inheritance.
Pleiotropy: A single gene influencing multiple phenotypic traits.
Complete Dominance: Dominant and heterozygous phenotypes appear identical.
Incomplete Dominance: Heterozygote displays a mixed phenotype.
Co-Dominance: Two alleles express distinct phenotypic traits simultaneously.

Chromosomal Components and Functions

Sister Chromatids: Identical copies of a chromosome formed during DNA replication.
Homologous Chromosomes: Chromosome pairs that are similar but not identical.
Ending Chromatids: When chromatids pull apart during cell division, leading to genetic diversity.

Differences Between Cells

Somatic Cells: Diploid human cells, such as skin, muscle, or blood cells.
Gametes: Haploid cells (sperm and eggs) essential for sexual reproduction.

Sexual and Asexual Reproduction

Sexual Reproduction: Requires fusion of gametes; produces genetic variation.
Asexual Reproduction: No gamete fusion; results in identical clones through processes like budding or binary fission.
Hermaphroditism: Organisms that can self-fertilize or cross-fertilize.

Karyotyping and Chromosome Identification

Human Karyotype: 46 chromosomes arranged in 23 homologous pairs; sex is determined by the 23rd pair.
Male Karyotype: Presence of XY chromosomes.
Female Karyotype: Presence of XX chromosomes.

Cell Division Processes

Mitosis: Produces two identical daughter cells with the same chromosome number as the parent cell.
Meiosis: Produces four genetically diverse haploid daughter cells; involves two rounds of division.

Unique Events in Meiosis

Crossing Over: Exchange of genetic material between homologous chromosomes during Prophase I.
Independent Assortment: Random distribution of homologous chromosomes during meiosis.
Reduction Division: Halving chromosome number during meiosis.

Genetic Variation Mechanisms

Independent Assortment: Random alignment and separation of homologous chromosomes leading to variation.
Crossing Over: Transfer of genetic material between homologous chromosomes during prophase I.
Mutations: Changes in DNA sequence contributing to diversity.

Generational Biology

Alternation of Generations: Life cycle that alternates between haploid gametophyte and diploid sporophyte stages.

Mendelian Genetics

Blending Hypothesis: Discredited; failed to explain inheritance patterns adequately.
Particulate Hypothesis: Established foundation of genetics via Mendel's pea plant experiments, showing traits are inherited as discrete units.

Advantages of Using Peas in Genetic Studies

Peas offer distinct traits, ease of cultivation, and quick reproductive cycles, making them ideal for Mendelian experimentation.

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Description

Prepare for your Exam 1 in BIO 104 with this review quiz focusing on key definitions in genetics and heredity. You'll find essential terms like heredity, variation, and genetics covered, helping you solidify your understanding. Make sure you're ready to tackle these concepts on the exam!