Introduction to Genetics - 7.1 Flashcards
(25 cards)
What is the scientific study of heredity?
Genetics
Genetics is the study of how traits are inherited through interactions of alleles.
Who is considered the father of genetics?
Gregor Mendel
Mendel conducted experiments with pea plants in the mid-1800s.
What did Mendel experiment with in his monastery garden?
Pea plants
Mendel studied seven traits or characteristics of pea plants.
What is the principle of dominance?
Some alleles are dominant and others are recessive
Dominant alleles suppress the expression of recessive alleles.
What does segregation refer to in genetics?
A gamete carries only one copy of each gene
This principle explains how alleles are separated during gamete formation.
What is the principle of independent assortment?
Genes for different traits segregate independently from one another
This principle describes how different traits are inherited separately.
Define ‘trait’ in genetics.
A specific characteristic varying among individuals
Example: eye color.
What is a gene?
A portion of DNA determining a trait; found on the chromosomes
Example: the gene for eye color.
What are gametes?
Reproductive cells (sex cells; sperm & egg)
Gametes are involved in sexual reproduction.
What is heredity?
Passing of traits from parent to offspring
Heredity is a key concept in genetics.
What are alleles?
The different forms of a trait that make up a gene pair
Alleles can be dominant or recessive.
Define homozygous.
Having the same genes for a particular characteristic
Example: AA, aa, BB, bb.
Define heterozygous.
Having two different genes for a particular characteristic
Example: Aa, Bb, Cc.
What is genotype?
The genetic makeup of an organism
Genotype refers to the specific alleles present.
What is phenotype?
The physical appearance of an organism
Phenotype is what the organism looks like.
True or False: A dominant allele will be expressed with only one copy present.
True
Dominant alleles are represented with capital letters.
True or False: A recessive allele will be expressed when a dominant allele is present.
False
Recessive alleles are covered up by dominant alleles.
What is a Punnett Square used for?
To predict the phenotype and genotype of offspring
It is a handy tool in genetics.
Fill in the blank: A hybrid is the offspring of two parents with _______ traits.
different
Hybrid can also refer to a half breed.
What is the expected probability of a child having a disease if both parents are heterozygous for that trait?
1 in 4
This is based on Mendel’s principles of inheritance.
What is incomplete dominance?
The heterozygous phenotype is somewhere between both homozygous phenotypes
Example: pink flowers from red and white parents.
What is codominance?
Both alleles contribute to the phenotype; neither allele is dominant
Example: roan cattle.
What are multiple alleles?
More than two allele possibilities
Example: blood type.
What are polygenic traits?
Traits controlled by more than one gene
Example: skin color.
