Gentics unit test

How many chromosomes do normal human body cells contain?

46

During meiosis I, chromosomes exchange genetic information, a process known as ____

Crossing over

Sex cells are called

Gametes

down syndrome occurs because of

an extra copy of chromosome 21 a condition known as trisomy 21.

Human blood type AB is a trait that results from both codominance and ___

multiple alleles.

Prior to cell division, the original chromosome and the duplicate it is attached to are called

sister chromatids.

In male mammals, meiosis results from the formation of

four haploid cells.

each parent passes on to its offspring only one of its two alleles for a gene. What is this phenomenon called?

The Law of Segregation.

In what molecules is genetic information stored?

Genetic information is stored in DNA molecules, which contain sequences of nucleotides that encode instructions for building proteins and regulating various cellular processes.

at which phase of meiosis does crossing over occur?

Crossing over occurs during prophase I.

why is down syndrome also called trisomy 21?

It is called trisomy 21 because individuals with Down syndrome have an extra copy of chromosome 21, resulting in three copies instead of the usual two.

when a dominant allele and a recessive allele appear in the genotype of an insect with incomplete dominance for a given characteristic which trait(s) appear(s) in the phenotype?

The phenotype displays a blend of traits from both alleles, resulting in a third, intermediate phenotype.

what is the likely coat colour of a dog that has codominant black and white alleles for coat colour?

A dog with codominant black and white alleles will express both colours in its coat, resulting in a unique pattern where black and white fur may mix or appear in patches. This means that instead of being solid black or solid white, the coat may have distinct black spots on white fur, or vice versa, showcasing both colours equally.

in X-linked inheritance, which sex is more likely to posses the recessive phenotype? which sex is more likely to be a carrier of the recessive allele?

In X-linked inheritance, males are more likely to express the recessive phenotype because they have only one X chromosome. Females are more likely to be carriers of the recessive allele since they have two X chromosomes, allowing them to inherit one normal allele.