Life 102 Exam 3

Binary Fission

A method of asexual reproduction in which a single organism divides into two identical organisms.

Mitosis

A process of cell division that results in two genetically identical daughter cells, used for growth and repair.

Meiosis

A specialized form of cell division that results in four genetically diverse gametes, each with half the chromosome number of the original cell.

Haploid

A cell with one complete set of chromosomes, typical of gametes (e.g., sperm and eggs).

Diploid

A cell containing two complete sets of chromosomes, one from each parent, typical of somatic cells.

Zygote

The fertilized egg formed when a sperm cell merges with an egg cell, it is diploid.

Gamete

A reproductive cell (sperm or egg) that is haploid and participates in sexual reproduction.

Cytokinesis

The process that follows mitosis, resulting in the physical separation of the cytoplasm and the creation of two daughter cells.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis that increases genetic variation.

Punnett Square

A diagram used to predict the genetic outcome of a cross between two individuals, showing the possible genotypes of the offspring.

Nondisjunction

An error in cell division that results in gametes with an abnormal number of chromosomes.

Chromosome

A long strand of DNA wrapped around proteins, which carries genetic information.

Allele

A variant form of a gene that can result in different traits.

Dominant Allele

An allele that expresses its trait even in the presence of another different allele.

Recessive Allele

An allele that expresses its trait only when two copies are present.

Genotype

The genetic makeup of an organism, represented by the alleles inherited from its parents.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by its genotype.

Independent Assortment

The principle that alleles for different traits segregate independently of each other during gamete formation.

Asexual Reproduction

A mode of reproduction where offspring are produced from a single organism without the involvement of gametes.

Sexual Reproduction

A mode of reproduction that involves the fusion of male and female gametes, resulting in genetically diverse offspring.

Somatic Cells

Cells that make up most of the body tissues and organs, which are diploid and undergo mitosis.

Gametes Formation

The process through which haploid cells (sperm and eggs) are produced via meiosis.

Fertilization

The process by which a sperm cell and an egg cell unite to form a zygote.

Chromatid

Each of the two identical halves of a chromosome that are created during DNA replication.

Tetrad

A structure that forms during meiosis, consisting of two homologous chromosomes each composed of two sister chromatids.

Genetic Variation

Diversity in gene frequencies, crucial for evolution and adaptation, influenced by processes like crossing over and independent assortment.

Karyotype

A visual representation of an individual's complete set of chromosomes, used to diagnose genetic disorders.

Gene

A segment of DNA that contains the instructions for the synthesis of proteins, which determine traits.

Homozygous

An organism that has two identical alleles for a particular gene.

Heterozygous

An organism that has two different alleles for a particular gene.

Locus

The specific physical location of a gene on a chromosome.

P1 Generation

The parental generation in a genetic cross, from which the F1 generation is derived.

F1 Generation

The first generation of offspring produced from a genetic cross.

F2 Generation

The second generation of offspring resulting from a cross between two F1 individuals.

Trait

A characteristic or feature of an organism that can be inherited.

Codominance

A genetic situation in which both alleles in a heterozygote are expressed equally, leading to a phenotype that is a blend of both.

Incomplete Dominance

A form of inheritance where the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.

Polygenic Inheritance

A trait controlled by multiple genes, leading to a continuous range of phenotypes.

Sex-linked Traits

Traits that are associated with genes located on sex chromosomes, often affecting one sex more than the other.

Linkage

The tendency of genes located close to one another on a chromosome to be inherited together.

Environmental Influence

The effect of external factors on the expression of genetic traits.

Expressivity

The degree to which a genotype is expressed in the phenotype, varying among individuals.

Penetrance

The probability of a gene or allele being expressed, manifesting in an expected phenotype.

Test Cross

A genetic cross between an individual with an unknown genotype and a homozygous recessive individual to