Unit 5: Heredity, Meiosis, and Sexual Life Cycles

These flashcards cover key terms and concepts related to heredity, meiosis, and sexual life cycles in biology.

Asexual Reproduction

A mode of reproduction where a single parent passes copies of all its genes to offspring, resulting in genetically identical clones.

Sexual Reproduction

A form of reproduction that involves the contribution of genes from two parents, leading to greater genetic variation in offspring.

Meiosis

A type of cell division that reduces the chromosome number from diploid to haploid, producing gametes.

Gametes

Reproductive cells (sperm and ova) that transmit genes from one generation to the next.

Homologous Chromosomes

Pairs of chromosomes that are similar in shape, size, and genetic content; one chromosome from each pair is inherited from each parent.

Karyotype

A visual representation of an organism's complete set of chromosomes arranged in pairs.

Diploid (2n)

A cell condition where it contains two sets of chromosomes, one from each parent.

Haploid (n)

A cell condition where it contains one set of chromosomes, typically found in gametes.

Crossing Over

The process during prophase I of meiosis where homologous chromosomes exchange genetic material, increasing genetic diversity.

Independent Assortment

The random distribution of homologous chromosome pairs during meiosis, contributing to genetic variation.

Zygote

The fertilized egg that results from the fusion of two haploid gametes; it is diploid.

Allele

Different versions of a gene that account for variations in inherited characteristics.

Phenotype

The observable traits or characteristics of an organism determined by its genotype.

Genotype

The genetic makeup of an organism; the combination of alleles it possesses.

Test Cross

A breeding experiment used to determine if an individual showing a dominant trait is homozygous or heterozygous by crossing it with a recessive individual.

Mendel's Law of Segregation

The principle that states that the two alleles for a trait separate during gamete formation and randomly unite at fertilization.

Mendel's Law of Independent Assortment

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

X-linked Inheritance

A pattern of inheritance in which a gene is located on the X chromosome, often exhibiting differences in expression between males and females.

Nondisjunction

An error in cell division where homologous chromosomes or sister chromatids fail to separate properly, leading to genetic disorders such as Down syndrome.

Pedigree

A diagram that shows the relationships between parents and offspring across generations, used to trace inheritance patterns.