BIO 171 EXAM 3 !!

Allele

Different forms of a gene that arise by mutation and are found at the same place on a chromosome.

Centromere

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

Chromosome

A structure made of DNA and proteins that carries genetic information in the form of genes.

Cytokinesis

The final phase of cell division, where the cytoplasm divides, resulting in two daughter cells.

Diploid

A cell or organism with two sets of chromosomes (one set from each parent).

Gametes

Reproductive cells (sperm and egg) that carry half the genetic material of a parent.

Haploid

A cell or organism with one set of chromosomes, as seen in gametes.

Homologous Chromosome

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 grows, replicates its DNA, and prepares for cell division.

M-phase

The phase of the cell cycle where mitosis or meiosis occurs, resulting in the division of the nucleus and cytoplasm.

Meiosis

A type of cell division that reduces the chromosome number by half, producing four haploid cells (gametes).

Mitosis

A type of cell division that results in two identical diploid daughter cells.

Nuclear DNA

The DNA found in the nucleus of a cell, responsible for coding genetic information.

Plasmid

A small, circular DNA molecule found in bacteria, separate from the chromosomal DNA.

S-phase

The phase of interphase where DNA is replicated.

Sexual Reproduction

Reproduction involving the fusion of two gametes (sperm and egg), producing offspring with genetic contributions from both parents.

Sister Chromatids

Identical copies of a chromosome, connected by a centromere, that are formed during DNA replication.

Somatic Cells

Any cells in the body that are not gametes (sperm or egg).

Unicellular

An organism that consists of a single cell.

Advantageous Mutation

A mutation that provides a beneficial effect, increasing an organism's fitness.

Aneuploidy

A condition where a cell has an abnormal number of chromosomes (either too many or too few).

Asexual Reproduction

Reproduction that does not involve the fusion of gametes, resulting in offspring genetically identical to the parent.

Beneficial Mutation

A mutation that improves the survival or reproductive success of an organism.

Bivalent

A pair of homologous chromosomes that are aligned during meiosis.

Chiasmata

The points where homologous chromosomes exchange genetic material during meiosis.

Deleterious Mutation

A mutation that negatively affects an organism's fitness or survival.

Egg

The female gamete in sexual reproduction.

Fertilization

The fusion of male and female gametes to form a zygote.

Frameshift Mutation

A mutation caused by the insertion or deletion of a nucleotide, leading to a shift in the reading frame of the gene.

Gene Deletion

The loss of a segment of a chromosome or a portion of a gene.

Gene Duplication

The process by which a section of a chromosome is duplicated, leading to multiple copies of a gene.

Germ Cells

Reproductive cells (sperm and egg) that carry half the genetic material of an organism.

Germ-Line Mutation

A mutation that occurs in the germ cells and can be passed on to offspring.

Indel (Insertion/Deletion)

A type of mutation where one or more nucleotides are inserted into or deleted from the DNA sequence.

Independent Assortment

The process during meiosis where chromosomes are randomly distributed into gametes, creating genetic variation.

Inversion

A chromosomal mutation where a segment of a chromosome is reversed end to end.

Locus

The specific location of a gene on a chromosome.

Metaphase I and II

The stages of meiosis where chromosomes are aligned at the cell's equator before being separated into daughter cells.

Missense Mutation

A mutation that changes one amino acid in a protein, potentially altering its function.

Neutral Mutation

A mutation that has no significant effect on an organism's fitness.

Nonsense Mutation

A mutation that changes a codon to a stop codon, resulting in a truncated protein.

Nonsynonymous Mutation

A mutation that changes the amino acid sequence of a protein.

Point Mutation

A mutation that affects a single nucleotide in the DNA sequence.

Polyploidy

A condition where an organism has more than two complete sets of chromosomes.

Reciprocal Translocation

A type of chromosomal mutation where segments from two non-homologous chromosomes are exchanged.

Recombination

The process by which genetic material is exchanged between homologous chromosomes during meiosis, increasing genetic diversity.

Somatic Mutation

A mutation that occurs in the non-reproductive cells and cannot be passed to offspring.

Substitution

A mutation where one base pair in the DNA sequence is replaced by another.

Synonymous Mutation

A mutation that does not change the amino acid sequence of a protein.

Sperm

The male gamete in sexual reproduction.

Tetrad

A structure formed during meiosis when homologous chromosomes pair up and exchange genetic material.

Zygote

The fertilized egg cell formed by the fusion of sperm and egg.

Carrier

An individual who carries one copy of a recessive allele but does not express the associated trait.

Dominant

An allele that expresses its phenotype even when only one copy is present.

Dihybrid Cross

A genetic cross that tracks the inheritance of two traits.

F1 Cross

A cross between two individuals from the first filial generation (F1).

F1 Generation

The first generation of offspring, typically produced from the parental (P) generation.

F2 Cross

A cross between individuals from the second filial generation (F2).

F2 Generation

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

Gamete

A reproductive cell (sperm or egg) containing half the genetic material of an organism.

Genotype

The genetic constitution of an organism (its allele combinations).

Heterozygous

Having two different alleles for a particular gene.

Homozygous

Having two identical alleles for a particular gene.

Hybridization

The process of crossing different individuals to produce offspring with a mixture of traits.

Mendel’s Law of Independent Assortment

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

Mendel’s Law of Segregation

The principle that each allele pair segregates during gamete formation, and each gamete receives one allele.

Monohybrid Cross

A genetic cross that tracks the inheritance of one trait.

Parental (P) Generation

The original generation of individuals used in a genetic cross.

Parental Cross

A cross between two individuals from the parental generation.

Phenotype

The observable physical characteristics of an organism, determined by its genotype and environment.

Punnett Square

A diagram used to predict the genetic outcomes of a cross between two individuals.

Recessive

An allele that is only expressed when two copies are present (homozygous).

Segregate

The separation of alleles during gamete formation.

Testcross

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

True-Breeding

Organisms that, when self-crossed, always produce offspring with the same traits.

Blending Inheritance

An outdated theory that offspring inherit a blend of parental traits rather than discrete genes.

Blood Type

A classification system for blood based on the presence of specific antigens (A, B, and Rh).

Autosome

Any chromosome that is not a sex chromosome.

Bivalent

A pair of homologous chromosomes that align during meiosis.

Chiasma

The point where homologous chromosomes exchange genetic material during meiosis.

Drosophila melanogaster

A species of fruit fly widely used in genetic research.

Genetic Distance

The relative distance between two genes on a chromosome, measured by the frequency of recombination.

Linkage (Genetic Linkage)

The tendency of genes located close to each other on a chromosome to be inherited together.

Linkage Mapping

A method used to determine the relative positions of genes on a chromosome.

Model Organism

An organism used in scientific research due to its practical advantages, like the fruit fly or mouse.

Non-Recombinant Type

Offspring whose genetic material has not undergone recombination.

Parental Type

An offspring whose genotype matches one of the parents.

Reciprocal Cross

A genetic cross where the sexes of the parents are reversed to determine if traits are sex-linked.

Recombinant Type

Offspring that exhibit new genetic combinations due to recombination.

Sex Chromosome

A chromosome involved in determining an individual's sex (X or Y).

Sex-Linkage

The inheritance of traits associated with genes located on sex chromosomes.

X Chromosome

One of the two sex chromosomes, present in both males and females.

X-Linked

A trait associated with a gene located on the X chromosome.

Y Chromosome

One of the two sex chromosomes, found only in males.

Codominance

A type of inheritance where both alleles are equally expressed in the heterozygote.

Complete Dominance

A type of inheritance where the dominant allele completely masks the effect of the recessive allele.

Epistasis

A gene x gene interaction where one gene masks the expression of another gene.

Incomplete Dominance

A type of inheritance where the heterozygote exhibits an intermediate phenotype.

Multiple Alleles

When a gene has more than two possible alleles.

Pedigree

A family tree diagram used to track the inheritance of a trait over generations.