Genetics Flashcards
What is genetics the study of?
Inherited traits
What are single gene traits?
Any of two forms not intermediate results
- example, attached or unattached earlobes
What is a chromosome?
The nucleus of each cell contains DNA molecules that are packaged into threadlike structures called chromosomes
Each chromosome is made of DNA tightly coiled many times
What is a karyotype
An individual’s complete set of chromosomes
They help determine the:
- species of an organism
- if it has a genetic abnormality
- biological sex of the organism (in humans this is the last set of chromosomes)
What is a gene?
A unit of hereditary information; a portion of DNA that determines a certain trait
What is an allele?
A variation of a gene that results in the observable traits an organism expresses
Example: gene= hair colour
allele= black hair or brown hair
what does heterozygous mean’.
individual inherits different alleles of a gene from both parents
What does homozygous mean?
individuals inherit the same alleles of a gene from both parents
when do dominant alleles show their effect?
Always, even if the individual only has one copy
when do recessive alleles show their effect?
Only when have two copies of the allele
what is a genotype?
Organism’s genetic information
what is a phenotype?
Organism’s observable traits
what do sex chromosomes do?
determine the organism’s biological sex
what does an x x chromosome mean?
Female
W hat does an XY chromosome mean?
male
