Biology Lecture Notes Review

These flashcards cover key concepts related to genetics and plant biology, aiding in the understanding of the material discussed in the lectures.

Recombination

The process where genetic material is rearranged to produce offspring with combinations of traits that differ from those found in either parent.

Homologous Regions

Sequences of DNA on different chromosomes that are highly similar or identical, allowing for accurate genetic material exchange during meiosis.

Gamete

A specialized sex cell that contains half the genetic material of a normal body cell (e.g., sperm and egg in animals).

Zygote

The single diploid cell formed by the fusion of two gametes during fertilization.

Allele

An alternative version of a specific gene.

Sister Chromatids

Two identical copies of a single replicated chromosome, connected at a central point called the centromere.

Haploid (n)

A cell containing only one set of chromosomes.

Diploid (2n)

A cell containing two sets of chromosomes, one set inherited from each parent.

Chiasma (plural: Chiasmata)

The X-shaped structure where homologous, non-sister chromatids have exchanged genetic material during recombination.

Sex Chromosome

The specific chromosomes that determine the biological sex of an organism (e.g., X and Y chromosomes in humans).

Diploid Life Cycle

The majority of an organism's life spent in a diploid (zygotic/somatic) stage compared to a brief haploid (gametic) stage.

Independent Assortment

The random orientation of maternal and paternal chromosomes during meiosis, resulting in varied genetic combinations.

Mendelian Genetics

The study of the inheritance of traits that follow specific patterns established by Gregor Mendel.

Dominant Allele

An allele that is fully expressed in the phenotype, masking the effect of a recessive allele.

Recessive Allele

An allele whose phenotypic effect is completely masked in the presence of a dominant allele.

Homozygote

An organism with a pair of identical alleles for a gene.

Heterozygote

An organism with two different alleles for a gene.

Principle of Segregation

During gamete formation, the two alleles for a heritable character segregate from each other.

Principle of Independent Assortment

Each pair of alleles segregates independently of every other pair of alleles during gamete formation.

Product Rule

The probability of two or more independent events occurring together is found by multiplying their individual probabilities.

Sum Rule

The probability that any one of two or more mutually exclusive events will occur is found by adding their individual probabilities.

Chromosome Theory of Inheritance

The understanding that Mendelian genes are located on chromosomes, which segregate and assort independently during meiosis.

Pleiotropy

A genetic phenomenon where a single gene influences multiple phenotypic traits.

Polygenic Inheritance

The additive effect of two or more genes on a single phenotypic character.

Genetic Linkage

Genes that are located close together on the same chromosome, leading to them being inherited together more often than not.

Sex-Linked Genes

Genes located on sex chromosomes, often impacting traits related to gender.

X-Inactivation

A process in female mammals where one of the two X chromosomes is randomly and permanently silenced to prevent double dosing of X-linked genes.

Chromosomal Abnormalities

Alterations in chromosome structure or number that can lead to genetic disorders.