BSC1010L Quiz 8

Body cells inherit ___ chromosomes, ____ from each parent

46, 23

The genetic information in gametes determines an individual’s? (2)

Physical and physiological traits

Meiosis is a special cell division process that takes the ______ (haploid/diploid) number of chromosomes (#) and changes it to _________ (haploid/diploid) (#).

Diploid (46 chromosomes) to haploid (23 chromosomes)

Gametes are formed by _______ (reducing/doubling) the number of chromosomes from ____ to ____.

Reducing, 46 to 23

How is genetic material exchanged in meiosis?

Crossing over

T or F: Gametes produced during meiosis are genetically identical

False. Meiosis is a form of sexual reproduction, and the gametes produced will be genetically different (as a result of crossing over).

Genes are present on what?

Chromosomes

T or F: Genes on chromosomes can exist in more than one form

True

What are the different forms of genes called?

Alleles

We inherit ____ alleles for each trait.

Two

Where do the two alleles we inherit for each trait come from?

We get one from our mom and one from our dad

An individual who is heterozygous for a trait has inherited…

Two different alleles

An individual who is homozygous for a trait has inherited…

Two of the same alleles

If an individual inherits one allele for brown eyes and one allele for green eyes, what are they considered? Homozygous or heterozygous?

Heterozygous

If an individual inherits one allele for green eyes and another allele for green eyes, what are they considered? Homozygous or heterozygous?

Homozygous

In a heterozygous individual, what allele is expressed?

The dominant trait

T or F: Dominant traits are represented by lowercase letters

False. Dominant traits are represented by uppercase letters

In heterozygous individuals, which trait is not expressed?

The recessive trait

How do we represent recessive traits?

We use lowercase letters

The genotype of an individual is represented by a combination of?

Alleles
ex./ GG, Gg, gg

What is a phenotype?

The physical description of a trait
ex./ Green eyes

Traits are produced from..

Alleles

T or F: Alleles can be visible or invisible

True

What are examples of visible traits? (2)

Eye color and height

What are examples of invisible traits? (2)

Blood type, color of your vision

Invisible traits are also known as ______ traits.

Physiological

What is an example of a physiological trait controlled by one gene?

The ability to taste PTC (Bitter Taste Gene)

There are _____ chromosome shapes in humans: the ___ and ___ chromosomes.

Two; X, Y

Which chromosome shape is bigger?

The X chromosome

The X chromosome carries traits that are linked to the ____ of an individual.

Sex

The traits linked to sex are also known as.. (2)

Sex-linked or X-linked traits

What is an example of an X-linked trait?

Color blindness

What are the two combinations of chromosomes that determine the sex of an individual?

XX and XY

XX means the sex of _____ while XY means the sex of ____

Female, male

Characteristics that are only found in males are associated with which chromosome?

The Y chromosome

What are Y-linked alleles?

Traits associated with the Y chromosome that are only found in males

T or F: Some inherited traits are controlled by both alleles

True

What does it mean for inherited traits to be controlled by both alleles?

The two alleles inherited are equally as dominant

How are alleles/traits in co-dominant organisms expressed?

They are expressed individually of each other

What is an example of codominance?

Human blood type

What are the co-dominant blood type alleles?

I^A and I^B (A and B)

What is the recessive allele for blood type?

i (O)