Bio Unit 5 Heredity Flashcards
What is heredity?
The passing of traits from parents to offspring.
True or False: Alleles are different forms of a gene.
True
What is the genotype?
The genetic makeup of an organism.
What is the phenotype?
The physical expression of a genetic trait.
Fill in the blank: The law of segregation states that alleles segregate during gamete formation.
alleles segregate during gamete formation.
What is a dominant allele?
An allele that expresses its trait even in the presence of a recessive allele.
What is a recessive allele?
An allele that only expresses its trait when two copies are present.
What does a Punnett square illustrate?
The possible genotypes of offspring from a genetic cross.
True or False: A homozygous organism has two identical alleles for a trait.
True
What is incomplete dominance?
A genetic situation where neither allele is completely dominant, resulting in a blended phenotype.
Define codominance.
A genetic scenario where both alleles in a heterozygote are fully expressed.
What is a dihybrid cross?
A genetic cross that examines two traits simultaneously.
Fill in the blank: The locus is the physical location of a gene on a chromosome.
the physical location of a gene on a chromosome.
What is a pedigree chart used for?
To track inheritance patterns of traits through generations.
True or False: Sex-linked traits are often found on the Y chromosome.
False
What is epistasis?
A genetic interaction where one gene masks or modifies the expression of another gene.
What does the term ‘polygenic inheritance’ refer to?
Inheritance of traits that are controlled by multiple genes.
What is a test cross?
A cross between an individual with an unknown genotype and a homozygous recessive individual.
The independent assortment principle states that alleles for different traits segregate independently.
alleles for different traits segregate independently assortment
What is a carrier in genetics?
An individual who has one copy of a recessive allele and does not express the trait.
True or False: Genetic drift can lead to a change in allele frequencies in a population.
True
Define gene linkage.
The tendency of alleles located close together on a chromosome to be inherited together.
What is the purpose of the Human Genome Project?
To map and understand all the genes of the human species.
Genes vs Alleles vs trait
segments of DNA that encode proteins; A section of DNA that controls a trait.
Alleles a specific version of that gene.
Trait: A specific characteristic.
What is a mutation?
A change in the DNA sequence that can lead to changes in phenotype.
Meiosis:
The process of cell division that creates gametes.
Crossing Over
A process during Meiosis where homologous chromosomes will pair up and exchange genetic information
Homologous chromosomes vs Sister Chromatidds
Homologous Chromsomes: Same length, shape, size, but have different alleles.
Sister Chromatids: Exact Duplicates.
Random Fertilization
Random fertilization is the concept that each sperm and egg combination is unique due to independent assortment and crossing over during meiosis, leading to a vast number of potential genetic combinations in offspring.
Any sperm can fertilize any egg.
Total Number of unique cells
2^n
n = chromosomes in a haploid cells.
Nondisjunction
An error that occurs in meiosis that creates cells with too many or little chromosomes. This can happen if the chromosomes fail to separate properly.
Meiosis I: n-1, n-1, n+1, n+1
Meiosis II: n, n, n-1, n+1
When this happens, the gametes produced often end in miscarriages or defects.
Down Syndrome
Extra chromosome on chromosome 21
Mendalls laws:
1: Law of Segregation
- An individual has two alleles for a gene, but only one allele is passed down to each gamete.
2: Law of Independent Assortment
- Genes for different traits assort independently during gamete formation; The inheritance of one gene does not affect the inheritance of another.
Non-Nuclear Inheritance
Inheritance of material outside of the nucleus. Things such as mitochondria are only passed down from the mother.
Phenotype Plasticity
The ability of an organism to change its phenotype based on environmental conditions, even tho its genotype stays the same.
