Biology - Genetics Unit Test

Allele

A variant form of a gene found at a specific location on a chromosome that can influence traits.

Chromosome Theory of Inheritance

A theory that explains how genes are inherited through chromosomes from parents to offspring.

Codominance

A genetic scenario where both alleles in a heterozygous individual are fully expressed, resulting in a phenotype that shows both traits.

Complete Dominance

A situation where one allele completely masks the effect of another allele at the same gene locus in a heterozygous individual.

Cross-fertilization

The process of fertilizing an ovule with pollen from a different flower, enhancing genetic diversity.

Dihybrid

An organism that has two different alleles for two traits.

Dihybrid Cross

A genetic cross that examines the inheritance patterns of two different traits at the same time.

Dominant

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

Gene Locus

The specific location of a gene on a chromosome.

Gene Map

A representation that shows the arrangement and relative positions of genes on a chromosome.

Genetic Linkage

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

Genotype

The genetic makeup of an individual, including all the alleles present for a particular trait.

Hereditary

Referring to traits or characteristics that are passed down from parents to offspring through genes.

Heritable

Describing traits that can be transmitted from one generation to the next through genetic inheritance.

Heterozygous

An organism that has two different alleles for a specific gene.

Homozygous

An organism that has two identical alleles for a specific gene.

Hybrid

An offspring resulting from the crossbreeding of two different species or varieties.

Incomplete Dominance

A genetic situation where neither allele is completely dominant, resulting in a blended phenotype in heterozygous individuals.

Inheritance Patterns

The predictable ways in which traits are passed from parents to offspring based on genetic principles.

Law of Independent Assortment

A principle stating that the alleles for different traits segregate independently during the formation of gametes.

Law of Segregation

A principle that states that during the formation of gametes, the two alleles for a trait separate so that each gamete carries only one allele for each gene.

Monohybrid

An organism that has two different alleles for one trait being studied.

Phenotype

The observable characteristics or traits of an organism, resulting from the interaction of its genotype with the environment.

Probability

The likelihood or chance of a particular genetic outcome occurring in offspring.

Punnett Square

A diagram used to predict the genetic combinations resulting from a cross between two individuals.

Recessive

An allele that does not manifest in the phenotype unless two copies are present.

Sex-linked Gene

A gene located on a sex chromosome, which often leads to traits that are expressed differently in males and females.

Test Cross

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

Prophase I

Nucleus dissolves at this stage. Crossing Over (exchange of genetic material) occurs at this phase.

Metaphase I

pairs of homologous chromosomes line up in the center of the cell. The centromere of each chromatid pair attaches to one spindle fibre.

Anaphase I

stage of meiosis I where homologous chromosomes are pulled to opposite ends of the cell. Note that chromatids do not separate - each duplicated chromosome still has two chromatids.

Telophase I

stage of meiosis I where the cytoplasm divides and two new cells form. Each new cell has one duplicated chromosome from each similar pair.

Prophase II

stage of meiosis II where duplicated chromosomes and spindle fibers reappear in each new cell.

Metaphase II

stage of meiosis II where the duplicated chromosomes move to the centre of the cell. Each centromere attaches to two spindle fibres instead of one.

Anaphase II

stage of meiosis II where the chromatids separate and move to opposite ends of the cell. Each chromatid is now an individual chromosome.

Telophase II

stage of meiosis II where spindle fibres disappear, and a nuclear membrane forms around each set of chromosomes. End result=4 haploid cells

Homologous chromosomes

Pair of chromosomes that are the same size, same appearance and same genes.

Crossing Over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis. This increases genetic variation.

Haploid

A cell that contains only one set of chromosomes instead of the normal pair.

Diploid

A cell that contains two sets of chromosomes; one inherited from the mother and one inherited from the father. Most body cells (nerve, brain, muscle, skin, etc.) are considered diploid cells.

Sperm

Male gamete (sex cell)

Egg

Female gamete (sex cell)

Gamete

The result of meiosis is 4 gametes, or sex cells, that each contain half of the genetic information in the parent organism.

Meiosis

A process in cell division that results in the production of 4 unique sex cells (gametes).

Fertilization

Process in sexual reproduction in which male and female gametes join to form a new diploid cell

the purpose of this process is to create genetically unique gametes with half the original DNA for sexual reproduction

meiosis

DNA

Deoxyribonucleic acid, genetic information carrier.

DNA Nucleotide

Building block of DNA, includes sugar, phosphate, base.

Deoxyribose

Five-carbon sugar in DNA nucleotides.

Nitrogen Base

Component of nucleotides; four types exist.

Adenine (A)

Nitrogen base that pairs with Thymine.

Thymine (T)

Nitrogen base that pairs with Adenine.

Guanine (G)

Nitrogen base that pairs with Cytosine.

Cytosine (C)

Nitrogen base that pairs with Guanine.

Complementary Base Pairing

Specific pairing of nitrogen bases in DNA.

DNA Replication

Process of duplicating DNA for cell division.

Chromosomes

Dense structures of DNA and protein in cells.

Codon

Triplet of nucleotides coding for an amino acid.

RNA

Ribonucleic acid, involved in protein synthesis.

RNA Nucleotide

Building block of RNA, includes ribose, phosphate, base.

Ribose

Five-carbon sugar in RNA nucleotides.

Cell Division

Process by which cells reproduce and repair.

Mitosis

Type of cell division for growth and repair.

Sexual Reproduction

Offspring produced by fusion of two gametes.

Asexual Reproduction

Offspring produced from a single parent.

Apoptosis

Programmed cell death to remove damaged cells.

Cancer Cells

Cells that divide uncontrollably and evade apoptosis.

Factors Affecting Mitosis

Environmental and chemical influences on cell division.

Protein Synthesis

Process of creating proteins from amino acids.

Homeostasis

Maintaining stable internal conditions in organisms.

Cell Cycle

Series of phases for cell growth and division.

DNA Helicase

Enzyme that unwinds DNA during replication.

Free Nucleotides

Available nucleotides that pair with template strands.

Mutations

Changes in DNA sequence that can affect traits.

64 Codons

Total possible combinations of three nucleotide sequences.

Interphase

Phase where the cell prepares for division.

Prophase

First stage of mitosis; chromosomes condense.

Metaphase

Chromosomes align at the cell's equator.

Anaphase

Sister chromatids are pulled apart to poles.

Telophase

Chromatids unwind; nuclear membranes reform.

Cytokinesis

Division of cytoplasm following mitosis.

Chromatin

Uncoiled DNA in the nucleus during interphase.

Centromere

Point where sister chromatids are joined.

Spindle Fibers

Structures that separate chromosomes during mitosis.

Diploid Cells

Cells containing two sets of chromosomes.

Haploid Cells

Cells containing one set of chromosomes.

Meiosis

Process of cell division for gamete formation.

Gametes

Sex cells produced through meiosis.

Zygote

Fertilized egg formed from gamete fusion.

Chromosome Number

Constant number of chromosomes per species.

Cytokinesis in Plants

Formation of a cell plate to divide cells.

Cytokinesis in Animals

Cell membrane pinches to separate daughter cells.

Chromosome Structure

Consists of two chromatids linked by centromere.

Cell Division Stages

Includes interphase, mitosis, and cytokinesis.

Mitosis Phases

Prophase, Metaphase, Anaphase, Telophase (PMAT).

Meiosis I

First division resulting in two haploid cells.

Meiosis II

Second division similar to mitosis.

Spermatogenesis

Formation of sperm cells through meiosis.

Oogenesis

Formation of egg cells through meiosis.

Chromosome Preservation

Maintaining chromosome number during cell division.