Chapter 3 Study Guide Flashcards
(25 cards)
Who cross-pollinated plants to observe different characteristics in his genetics experiments?
Gregor Mendel
What does the notation TT mean?
homozygous alleles
What does a pun net square do?
Shows all the possible outcomes of a genetic cross
An purebred animal with white feathers is crossed with a purebred animal with black feathers. Both of their offspring have black and white feathers. Why?
The alleles for feather color are codominant
The chromosome theory of inheritance states that what is carried from parents to offspring on chromosomes?
Genes
Traits refer to specific what?
Characteristics
An organism’s what is it’s genetic makeup?
genotype
Factors that control traits are called what?
Genes
The notation Tt means what?
Heterozygenous alleles
What is probability?
How likely it is for an event to occur
If a homozygous black guinea pig (BB) is crossed with a homozygous white guinea pig (bb) what is the probability that an offspring will be black?
100%, because black is a dominant color
An organisms physical appearance is what?
It’s phenotype
Who discovered that the sex cells of grasshoppers have half the number of chromosomes found in body cells?
Walter Sutton
When sex cells combine to produce offspring, each sex cell will contribute how many number of chromosomes found in body cells?
Half
The different forms of a gene are called what?
Alleles
In a flower, color is inherited by genes that show incomplete dominance. In such flowers, a cross between a homozygous red flower and a homozygous white flower will always result in pink flowers. A cross made between two pink flowers. What is the for each phenotype?
1 red, 2 pink, and 1 white
What kind of organism is the offspring of many generations of organisms that have had the same trait?
Purebred
If this allele is present, its trait will appear in the organism. What kind of trait?
Dominant
The process by which the number of chromosomes is reduced by half and sex cells form is called what?
Meiosis
If D represents the dominant allele of a gene, the d represents what?
The recessive allele
In a cross between two hybrid Tt pea plants, 50 percent of the offspring will be what?
Tt
An organism that has two dominant or two recessive alleles is said to be what?
Homozygous
Genes are carried from parents to their offspring through what?
Chromosomes
A woman gives birth to her son. Two years later, she gives birth to another son. What is the probability that her third child will be a girl?
The probability is 1 in 2, or 50 %. The two possible results are equally likely with each birth, because each birth is an in dependent event. The probability that one result will occur does not depend on previous births.