Unit Five

5.1 Genetics

Vocabulary

allele: one of a pair of genes that determine a specific trait

asexual reproduction: process of reproduction involving a single parent that results in offspring that are genetically identical to the parent

binary fission: type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells

budding: type of asexual reproduction in which organisms form as an offshoot from the parent

chromosome: structure located in the nucleus of a cell, made of DNA, that contains the genetic information needed to carry out cell functions and make a new cell

codominance: a cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together

conjugation: process in which paramecia and some prokaryotes exchange genetic information

DNA (deoxyribonucleic acid): the material found in a cell’s nucleus that determines the genetic traits of the organism

dominant trait: in a pair of alleles, the one that, if present, determines the trait

fertilization: process in sexual reproduction in which male and female reproductive cells join to form a new cell

fragmentation: a type of asexual reproduction in which an organism splits into smaller pieces which can each develop into mature, fully grown organisms that are identical to the original organism

gamete: sex cell

gene: segment of DNA, found on a chromosome, that determines the inheritance of a particular trait

generations: that which is generated or brought forth; offspring

genetics: the study of how traits are passed from parent to offspring

genotype: the set of genes carried by an organism

Gregor Mendel: Father of genetics who conducted pea plant experiments to determine how traits were passed from one generation to the next.

heredity: the passage of genetic instruction from one generation to the next generation

hybrid or heterozygous: refers to an organism that carries two different alleles for the same trait

homologous chromosome: chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location. The position of the genes on each homologous chromosome is the same, however the genes may contain different alleles.

incomplete dominance: a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blending of the parental traits

offspring: new organism produced by a living thing

phenotype: the physical appearance of an organism

pollination: transfer of pollen from the male reproductive structure to the female reproductive structure

Punnett Square: diagram that is used to predict an outcome of a particular cross or breeding experiment

pure breed or homozygous: refers to an organism that carries two dominant or two recessive alleles for a given trait

recessive trait: in a pair of alleles, the one that is masked in a dominant allele is present

selective breeding: the intentional breeding of organisms with desirable traits in an attempt to produce offspring with similar desirable characteristics or with improved traits

sexual reproduction: type of reproduction in which cells from two parents unite to form the first cell of a new organism

spores: in prokaryotes, fungi, and protists, any of a variety of thick-walled life cycle stages capable of surviving unfavorable conditions

vegetative propagation: method of asexual reproduction in plants, which enables a single parent to produce offspring that are genetically identical to the parent.

Videos: