bio quiz 4/9 Flashcards
Genetics
study of genes
Allele
variation of a gene
Dominant
trait or allele that masks the expression of another, recessive allele (DD or Dd)
Recessive
a trait that is expressed only when genotype is homozygous
Homozygous
two identical alleles
Heterozygous
two different versions of a gene
Genotype
genetic makeup of an organism, or the combination of genes it inherits from its parents
Phenotype
set of observable characteristics of an individual resulting from the interaction of its genotype with the environment (physical traits)
Carrier
individual who possesses a genetic variant (allele) associated with a disease or trait, but doesn’t exhibit symptoms of that condition, and can pass the allele to their offspring
Pedigree
diagram that visually represents the inheritance of a specific trait or disorder through generations of a family, using standardized symbols to denote individuals and their relationships
Incomplete dominance
neither allele for a trait is fully dominant, resulting in a heterozygous phenotype that is a blend of both homozygous phenotypes EX: pink flowers from red and white flowers
Codominance
both alleles of a gene are expressed in a heterozygous individual, resulting in both traits being visible or expressed simultaneously, rather than one masking the other
Multiple Alleles
gene having more than two alternative forms (alleles) within a population
Sex chromosome
a chromosome involved with determining the sex of an organism
Autosome
any chromosome that is not a sex chromosome
Sex-linked trait
characteristic determined by genes located on the sex chromosomes (X or Y), resulting in potentially different inheritance patterns in males and females
Polygenic trait
characteristics influenced by multiple genes, rather than a single gene, and often exhibit continuous variation
Gregor Mendel-who was he? What did he study? How?
Austrian Biologist, “father of modern genetics”, studied the inheritance of traits in pea plants, bred pea plants and observed the pattern of inheritance
Monohybrid crosses
genetic cross that examines the inheritance of a single trait
Who is Gregor Mendel?
Father of genetics
What did Gregor Mendel study and conclude about traits?
Mendel studied and breed pea plants to find out about the patterns of inheritance, and he concluded that traits are inherited as discrete units (now known as genes) that come in pairs, one from each parent, and that these traits can be dominant or recessive
What is probability?
extent to which something is probable; the likelihood of something happening or being the case
What is codominance?
situation where both alleles of a gene are expressed in a heterozygous individual, resulting in both traits being visible or expressed simultaneously, rather than one masking the other
What is incomplete dominance?
neither allele for a trait is fully dominant, resulting in a heterozygous phenotype that is a blend or intermediate between the two homozygous phenotypes
What are examples of polygenic inheritance?
skin color, height, eye color, and even complex conditions like diabetes and heart disease
What does multiple alleles mean and what is an example?
many different versions of a trait that exist within a population, ABO blood type system in humans is an example
What is the difference between dominant and recessive traits?
dominant trait is expressed even if only one copy of the allele is present, while a recessive trait is only expressed when two copies of the allele are present
What is the purpose of a punnett square?
predict the possible genotypes and phenotypes of offspring resulting from a genetic cross by visualizing the combinations of parental alleles
What is a pedigree?
Family tree, shows generational inheritance of traits and family relationships
What is the purpose of a pedigree?
helping to understand how traits are passed down through generations and identify potential genetic patterns
What are sex-linked traits?
characteristic determined by genes located on the sex chromosomes (X or Y), resulting in potentially different inheritance patterns in males and females
Why are sex-linked traits more common in males than in females?
they only have one X chromosome, meaning a single recessive allele on that chromosome will be expressed, whereas females, with two X chromosomes, may have a dominant allele on the other chromosome to mask the recessive one
What is an allele?
Variation of a gene
What does homozygous and heterozygous mean?
“homozygous” refers to having two identical alleles (versions) of a gene, while “heterozygous” means having two different alleles for the same gene
What is the difference between pure and hybrid?
“pure” refers to something that is unmixed or undiluted, while “hybrid” describes something that is a combination of two or more different things
