Science 2 Flashcards
What is a phenotype?
The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.
True or False: A dominant allele will always express its trait in the phenotype.
True
What is a recessive allele?
An allele that only expresses its trait in the phenotype when two copies are present.
Fill in the blank: A __________ is a reproductive cell that carries genetic information.
gamete
What is the function of chromosomes?
Chromosomes carry genetic information in the form of genes and are found in the nucleus of cells.
What does it mean if an organism is homozygous for a trait?
It has two identical alleles for that trait.
What does it mean if an organism is heterozygous for a trait?
It has two different alleles for that trait.
True or False: The phenotype can be influenced by environmental factors.
True
What is the relationship between genotype and phenotype?
The genotype is the genetic makeup of an organism, while the phenotype is the expression of that genotype in the organism’s traits.
Multiple Choice: Which of the following is an example of a dominant trait? A) Blue eyes B) Brown eyes C) Cystic fibrosis
B) Brown eyes
What are sex chromosomes?
Chromosomes that determine the sex of an organism, typically X and Y in mammals.
Fill in the blank: The physical expression of a trait is known as its __________.
phenotype
True or False: All traits are determined by a single pair of alleles.
False
What is a gamete’s role in reproduction?
Gametes fuse during fertilization to form a zygote, which develops into a new organism.
What are alleles?
Different forms of a gene that can exist at a specific locus on a chromosome.
Multiple Choice: Which of the following describes a phenotype? A) Genetic code B) Observable traits C) Chromosome structure
B) Observable traits
What is the main difference between dominant and recessive alleles?
Dominant alleles express their traits even when only one copy is present, while recessive alleles require two copies to be expressed.
Fill in the blank: An organism’s genetic makeup is referred to as its __________.
genotype
True or False: All organisms have the same number of chromosomes.
False
What are autosomes?
Chromosomes that are not sex chromosomes and are involved in determining general traits.
What is a karyotype?
A visual representation of the complete set of chromosomes in an organism.
Multiple Choice: How many pairs of chromosomes do humans typically have? A) 22 B) 23 C) 24
B) 23
What is the role of meiosis in gamete formation?
Meiosis reduces the chromosome number by half, resulting in haploid gametes.
