Flashcards in Chapter 4 - Lesson 1 Deck (25)
In single genes with 2 alleles, there is...
one dominant allele and one recessive allele
In single genes with multiple alleles, there are
3 or more forms of a gene code for a single trait.
________ is controlled by a gene with multiple alleles
There are _____ main blood types
The 4 main blood types are
A, B, AB and O
_____ alleles control the inheritance of blood types
The allele for blood type A and B are
The allele for blood type O is
Some human traits show a large number of ________ because the traits are controlled by many genes.
Traits that is controlled by many genes are
height and skin color
Sex chromosomes are
one of 23 pair of chromosomes in each body. It carries genes that determine whether a person is male or female.
Sex chromosomes are the only chromosome pair that
do not always match
Both of the female's sex chromosomes are _____ chromosomes
Males have ________ chromosomes
X and Y
When a sperm cell with an X chromosome fertilizes an egg, the egg has
2 X chromosomes and will develop into a girl
When a sperm with a Y chromosome fertilizes the egg, the egg has
1 X chromosome and 1 Y chromosome and will develop into a boy
Genes on the X and Y chromosomes are often called
sex linked genes
Traits controlled by sex linked genes are called
sex linked traits (such as colorblindness)
Males are more likely than females to have a sex linked trait that is controlled by
a recessive allele
Colorblindness is a trait controlled by
a recessive allele on the X chromsome
A carrier is
a person who has one recessive allele for a trait and one dominant allele. A carrier of a trait controlled by a recessive allele does not have the trait, but can pass the trait to the offspring.
Many of a person's characteristics are determined by
an interaction between genes and the environment
An example of a characteristic that is affected by the environment is
height. Lack of protein, minerals and vitamins can prevent a person from growing as tall as possible.
________ can also affect human skills, such as playing a musical instrument.
Environmental factors. Musical instruction is an environmental factor for a musician.