Biology: Quiz 4: Human Genetics

What would be a female bleeder's genotype? (Let X B stand for the normal condition for clotting and X b stand for the recessive hemophilia allele.)

Xb Xb

The extra chromosome which produces Down's syndrome is:

an autosome

What genotype produces voices?

bass and soprano is SS, of baritone and mezzo-soprano SA, and of tenor and alto AA.

Why would it be wise for a woman carrying the hemophilia gene to keep her son from being circumcised?

because the probability of hemophilia would be 1:2

The factors that are responsible for the ABO blood type, or the Rh, are located on the surface of the

erythrocyte

Some scientists believe that sickle-cell anemia is a beneficial mutation because it:

increases resistence to malaria

Nutrition affects development of the physical brain therefore:

nutrition is related to intelligence

The Rh ______ condition occurs in most of the world population.

positive

The traits for blood type and Rh are the result of the presence or absence of particular ______ on the erythrocytes.

proteins

Sex-linked inheritance refers to

recessive hereditary alleles usually being passed on the X chromosome.

In the ABO series, the gene for blood type O is______, while A and B are______genes, and AB is ______.

recessive, dominant, codominany

When using data from population genetics research:

the sample must have a high probability of representing the population

Why do identical twins have the same set of genes?

they were born of one fertilized ovum

A female can be susceptible to expressing hemophilia.

true

In general, the "Y" sex chromosome does not appear to exert as much genetic influence as the "X" chromosome.

true

The blood type trait is controlled by more than two alleles for a given gene and therefore is called multiple alleles.

true

The presence of tight ligaments in the thumb is a recessive trait.

true

A pedigree is very helpful to a counselor when

when they are predicting the probability of a recessive gene being present and the chances for an offspring to receive the gene and express the trait.

The Talmud permitted a father with hemophilia to have his son circumcised. Would this preclude all possible problems?

yes-if the mother is not a possible carrier

The genotype of persons with the sickle-cell trait, but often not exhibiting sickle-cell, is

HbS HbS

Turner's syndrome

(XO) An abnormality where one of the sex chromosomes is missing leaving a total of 45

When does nondisjunction occur which affects inheritance?

meiosis

In a large population, approximately 65 percent are tasters and 35 percent are nontasters. Does the class compare favorably to the general population?

yes

Klinefelter syndrome

(XXY) An abnormality affecting males where there is an extra X chromosome

Each member of a class sampled a piece of PTC testing paper. Thirty people sampled the chemical. Twenty persons were tasters. How many had heterozygous genes?

0-20

Each member of a class sampled a piece of PTC testing paper. Thirty people sampled the chemical. Twenty persons were tasters. How many had homozygous recessive genes?

10

Each member of a class sampled a piece of PTC testing paper. Thirty people sampled the chemical. Twenty persons were tasters. How many had homozygous genes?

10-30

Down's syndrome is a condition where an extra chromosome is produced on the _____ chromosome.

21st

A normal human body contains:

23 pairs of chromosomes, 46 total chromosomes

holandric genes

A gene located on the Y chromosome in XY species

Hemophilia

A hereditary condition for bleeding due to the inability to clot properly

Rh factor

An inherited protein found on the surface of the red blood cell membrane

The genotype of the person with normal red blood cells in all environmental conditions is

HbA HbA

pedigree

The ancestral history of an individual; a chart showing the history of a trait in the family

population genetics

The study of a hereditary trait in a large population

Two of the risk factors for Down's syndrome include which of the following?

-increased age of female -infectious hepatitis

Choose from the following list of diseases those that are sex-linked.

-night blindness -rolling eyeballs -nonfunctional sweat glands -white forelock -muscular dystrophy -certain deafness -color blindness -diabetes

Down Syndrome

A condition caused by the presence of an extra chromosome 21

gene pool

All of the genes present in a specific population

Codominance

Both members of an allelic pair contribute equally to the phenotype

gene frequency

How common the gene is in the population

sickle cell trait

In conditions of low oxygen some cells sickle

The large number of potential gene ______ make it unlikely that any two people will be identical.

combinations

The hemoglobin of sickle cell anemia:

differs from the normal protein by one amino acid

A family pedigree is a chart of various patterns that shows a general trend.

false

Hemophilia is a condition where the blood clotting action is dangerously high.

false

A person with Klinefelter's syndrome possesses:

has a extra X chromosome

What is true about the heterozygous sickle-cell (HbA HbS) condition?

sickle-cell anemia is expressed under conditions of oxygen deficiency

sickle cell anemia

A hereditary form of anemia