SBI 3U1 - Grade 11 Biology - Unit 2

Genetics

The field of biology that involves the study of how genetic information is passed from one generation of organisms or cells to the next generation.

Somatic Cells

A plant or animal cell that forms the body of the organism; excludes reproductive cells.

Interphase

The stage during which a cell carries out its normal functions, grows, and makes copies of its genetics material in preparation for the next stage of the cycle.

Mitosis

The stage during which a cell’s nucleus and genetic material divide.

Cytokinesis

Begins near the end of mitosis and involves the division of the cell cytoplasm and creation of a new cell.

Functions of cell division

Growth of the organism, repair tissues and organs, replace dead or dying cells.

Double helix

Two long strands of DNA that form a spiral shape.

Nucleotide

The individual units of each strand of DNA.

Growth 1 (G1)

Stage of interphase where the cell grows and performs normal functions while preparing for DNA replication.

Synthesis (S)

Stage of interphase where The cell copies its DNA to ensure each new cell will have a complete set.

Growth 2 (G2)

Stage of interphase where the cell grows more, checks for DNA errors, and prepares for division.

Prophase

Stage of mitosis where DNA condenses into chromosomes, the nuclear membrane breaks down, and spindle fibers start to form.

Metaphase

Stage of mitosis where Chromosomes line up in the middle of the cell, attached to spindle fibers.

Anaphase

Stage of mitosis where the spindle fibers pull sister chromatids apart to opposite sides of the cell.

Telophase

Stage of mitosis where two new nuclei form as the chromosomes loosen back into chromatin.

Genome

The complete DNA sequence of an organism.

Homologous chromosomes

A chromosome that contains the same sequence of genes as another chromosome.

Gene

A part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence.

Allele

A different form of the same gene.

Autosome

A chromosome that is not involved in determining the sex of an organism.

Sex Chromosomes

An X or Y chromosome, which determines the genetic sex of an organism.

Karyotype

A photograph of pairs of homologous chromosomes in a cell.

Sexual reproduction

Reproduction that requires two parents and produces genetically distinct offspring.

Gametes

A male or female reproductive cell.

Diploid

A cell that contains pairs of homologous chromosomes.

Haploid

A cell that contains half the number of chromosomes as the parent cell.

Fertilization

The process of combining gametes to form a zygote.

Zygote

A cell formed by the fusion of two gametes.

Meiosis

A specialized form of cell division that produces haploid gametes (sex cells, sperm and egg) from one diploid cell.

Non-Disjunction

The failure of homologous chromosomes (meiosis I) or sister chromatids (meiosis II) to separate properly during cell division, leading to gametes with an abnormal number of chromosomes

Down’s Syndrome

Genetic condition, where there is an extra chromosome 21.

Patau’s Syndrome

Genetic condition, where there is an extra chromosome 13.

Edward’s Syndrome

Genetic condition, where there is an extra chromosome 18.

Klinefelter’s Syndrome

Genetic condition in biological males, where there are two X chromosomes as well as a Y chromosome.

Trisomy X

Genetic condition in biological females, where there are three X chromosomes.

Turner’s Syndrome

Genetic condition in biological females, where there is only one X chromosome.

Sex-linked Traits

Characteristics determined by genes located on the sex chromosomes (X and Y), leading to unique inheritance patterns that can differ between males and females.

Incomplete dominance

Neither allele is completely dominant over the other. There is a blending of traits.

Co-dominance

Both alleles are dominant. Both traits are demonstrated at the same time.

Multiple Alleles

Genes that have more than 2 alleles. Example is human blood type, as there are three alleles involved.

Rhesus (Rh) factor

Rhesus is a protein found on the surface of red blood cells in some individuals. Individuals are classified as Rh-positive if they have the protein, and Rh-negative if they don't. Rh-positive is dominant over Rh-negative.

Pedigree

A diagram that shows the occurrence of certain traits through different generations of a family.

Selective Breeding

A reproductive strategy that involves breeding select organisms with desired traits.

Artificial Insemination

A reproductive strategy that involves artificial transfer of sperm into a female’s reproductive tract.

Embryo Transfer

A reproductive strategy. The process of fertilizing an egg from a desired female, harvesting the embryos, and transferring each into a surrogate mother.

Assisted Reproductive Technologies (ART)

Reproductive technology to assist humans who are not able to conceive a child.

In vitro fertilization (IVF)

Fertilization where the egg cell retrieved from the woman and fertilized outside the body in a laboratory.

Preimplantation Genetic Diagnosis (PGD

Testing embryos before implantation.

Therapeutic cloning

Production of genetically identical cells to treat diseases.

Reproductive cloning

Production of genetically identical cells to produce a genetically identical organism.

Transgenic Organisms

Organism whose genetic material contains DNA from a different species.

Genomics

Study of genomes and how genes work together to control phenotype.

Bioinformatics

Branch of biology that uses computer science to create and analyze large databases (i.e. The human genome)

Clustered Regularly Interspaced Short

Palindromic Repeats (CRISPR)

A powerful gene editing tool