alleles
the different forms of a trait that a gene may have
dominant
factor that dominates, or covers up, another factor
genetics
the study of how traits are inherited through the interactions of alleles
genotype
genetic makeup of an organism
heredity
passing of traits from parent to offspring
heterozygous
an organism that has two different alleles for a trait
homozygous
an organism with two alleles that are the same for a trait
hybrid
a plant that receives different genetic information for a trait from each parent
phenotype
the way an organism looks and behaves as a result of its genotype
Punnett square
a tool used to predict the number of times certain traits will occur
recessive
factor that disappears if a dominant trait is present
incomplete dominance
the offspring of two homozygous parents show an intermediate phenotype
polygenic
a group of gene pairs act together to produce a trait
sex-linked gene
an allele inherited on a sex chromosome
genetic engineering
biological and chemical methods to change the arrangement of DNA that makes up a gene
how alleles and genes are related
alleles are part of a gene; genes are on chromosomes
how do alleles separate during meiosis
alleles for each trait also separate into different sex cells. Every sex cell has 1 allele for each trait
what is the difference between genetics and heredity
heredity is the passing of traits from parents to offspring. Genetics is the study of heredity
what is a hybrid
a plant that receives different genetic information for a trait from each parent
how do we represent heterozygous genotypes, homozygous genotypes
Tt, TT
the three principles of heredity and am I able to write them down p. 132, table 2
1. traits are controlled by alleles on chromosomes
2. an allele's effect is dominant or recessive
3. when a pair of chromosomes separates during meiosis, the different allels for a trait move into separate sex cells
what is a mutation, what can cause it
changes or errors in the DNA when it is being copies during cell division; certain chemicals, Xrays, and radioactive materials can cause mutations
what is a recessive genetic disorder, how can it be inherited, what is an example, how does it occur
a genetic disorder caused by recessive genes
each parent passes a recessive allele to the child
cystic fibrosis
they occur when both parents have a recessive allele responsible for the disorder
what is a sex-linked disorder, how can it be inherited, what is an example, how does it occur
a condition that results from inheriting sex-linked genes; females when each X chromosomes has the recessive gene; male when his X chromosome has the recessive allele; color blindness
how is gender determined what do the chromosomes for a male look like, for a female
by the sperm passing either an X or a Y to the egg; female = XX male = XY
what is gene therapy, what particles are used, what does it do
gene transfer - first normal DNA or RNA is replaced in a virus. Then the virus delivers the normal DNA or RNA to target cells. It might help genetic disorders such as cystic fibrosis
how are plants genetically engineered, why is it helpful
find genes that produce desired traits in one plant and then insert those genes into a different plant. Genetically engineered tomotoes can be picked green then they continue to ripen so when you buy them at the stor