BIO 161 Exam 3 Study Guide Flashcards

A comprehensive set of vocabulary flashcards covering key terms and concepts related to biology chapters on cell division, genetics, and inheritance.

Eukaryotic Chromosomes

Structures composed of DNA and histones that contain genetic information.

Chromatin

A complex of DNA and protein found in the nucleus of eukaryotic cells during non-dividing phases.

Chromosome

A condensed structure of chromatin that forms during cell division.

Nucleosome

The basic unit of chromatin, consisting of DNA wrapped around histone proteins.

Centromere

The region of a chromosome where the two sister chromatids are joined.

Telomere

The protective end of a chromosome that prevents degradation.

Euchromatin

A lightly packed form of chromatin that is associated with active gene transcription.

Heterochromatin

A densely packed form of chromatin that is generally not active in transcription.

Karyotype

A display of the complete set of chromosomes in a cell, used for identifying chromosomal abnormalities.

Homologous Chromosomes

A pair of chromosomes, one from each parent, that are similar in shape, size, and genetic content.

Interphase

The phase of the cell cycle where the cell prepares for division, consisting of G1, S, and G2 phases.

M Phase

The phase of the cell cycle where mitosis and cytokinesis occur.

Cytokinesis

The process where the cytoplasm divides to form two daughter cells.

Mitosis

The process of cell division that produces two genetically identical daughter cells.

Spindle Apparatus

A structure composed of microtubules that segregates chromosomes during cell division.

Tumor Suppressor Proteins

Proteins that help regulate cell division and prevent tumor formation, e.g., p53.

Meiosis

A specialized type of cell division that reduces the chromosome number by half and produces gametes.

Haploid

A cell with a single set of chromosomes, typically gametes (sperm & egg).

Diploid

A cell with two sets of chromosomes, typically somatic cells.

Independent Assortment

The process whereby chromosomes are distributed randomly to daughter cells during meiosis.

Continuous Variation

Variation in traits that occur in a gradient, rather than as discrete categories.

Pleiotropic Genes

Genes that influence multiple, seemingly unrelated phenotypic traits.

Punnett Square

A diagram used to predict the genotype and phenotype combinations in genetic crosses.

Monohybrid Cross

A cross between two individuals that differ in one trait.

Dihybrid Cross

A cross between two individuals that differ in two traits.

F1 Generation

The first generation of offspring from a genetic cross.

F2 Generation

The second generation of offspring, produced from crossing individuals from the F1 generation.

Test Cross

A breeding experiment used to determine the genotype of an individual by crossing it with a homozygous recessive.

Incomplete Dominance

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

Co-Dominance

A form of inheritance where both alleles in a heterozygote are fully expressed.

Epistasis

The interaction between genes in which the presence of one gene can mask or modify the effects of another gene.

Genetic Counseling

A process to evaluate and understand a family's risk of genetic disorders.

Non-Disjunction

The failure of chromosomes to separate properly during cell division, leading to genetic disorders.

Pedigree Chart

A diagram that depicts the biological relationships between individuals in a family.

Genetic Disorders

Health conditions caused by abnormalities in genes or chromosomes.

Down Syndrome

A genetic disorder caused by having an extra copy of chromosome 21.

Turner Syndrome

A condition affecting females where one of the X chromosomes is missing or partially missing.

Klinefelter Syndrome

A condition in males who have an extra X chromosome, resulting in an XXY genotype.

Jacobs Syndrome

A condition in males caused by an extra Y chromosome (XYY).

Mitochondrial Diseases

Disorders related to dysfunctional mitochondria, often inherited maternally.

Sutton’s Theory of Chromosomal Inheritance

The theory that chromosomes are the carriers of genetic information.

Environmental Modifications of Genes

Changes in gene expression caused by environmental factors.