94 terms

Chapter 12: Inheritance Patterns and Human Genetics

True or False: A male can produce sperm that contains either X or a Y chromosome.
True or False: If an inherited disease is recessive and X-linked, then all males with one copy of the disease-causing gene will have the disease,
True or False: In a chromosome map, the percentage of crossing over between 2 genes is equal to the number of map units separating the genes.
True or False: The condition that results from the loss of an entire chromosome is called monosomy.
True or False: It is possible that a fragment of DNA may become detached from a chromosome and then reattach in the reverse orientation, resulting in a mutation called inversion.
True or False: Mutations that result from the substitution of one nitrogen-containing base for another are called deletions.
False. Deletions should be inverse
True or False: Changes in the DNA of an organism are called mutations.
True or False: If each parent carries a copy of the sickle cell gene, there is a one-in-four chance that their child will have sickle cell anemia.
True or False: Somatic mutations affect an organism's offspring.
False. Affect should be dont' affect
True or False: Mutations usually introduce new chromosomes into the genome of an organism.
False. Usually should be ALWAYS
True or False: Mutations are always harmful.
False. Always should be SOMETIMES
True or False: An individual who expresses a genetic disorder is called a carrier.
False. Genetic disorder should be sec-linked trait
True or False: A pedigree is a family record that shows how a trait is inherited over several generations.
True or False: An autosomal trait will occur with equal frequency in both males and females.
True or False: the expression of sex-linked genes is controlled by hormones.
False. Hormones should be sex chromosomes
True or False: Down syndrome occurs as a result of nondisjunction of chromosome 21 during meiosis.
True or False: Trisomy is the addition or removal of a single nitrogen-containing base.
True or False: Nondisjunction results from the failure of replicated chromosomes to seperate during cell division.
What are X and Y chromosomes called?
Sex chromosomes
Monosome : nondisjunction ::
A) chromatids : centromere ::
B) male : XY chromosomes ::
C) Haploid : mitosis ::
D) Meiosis : diploid ::
Female: XX ::
A) Female : gametes ::
B) Female : Eggs ::
C) Male : YY ::
D) male : XY ::
What is the best explanation for the observation that females rarely get the disease hemophilia?
A female could only get the disease by having a mother who is a carrier and a father who has the disease. Since most males with the disease do not survive to reproductive age, this is an extremely unlikely event.
Which of the following is NOT true of chromosome maps?
A) They depict the linear sequence of genes on a chromosome
B) They are constructed using crossing-over data from mating experiments
C) They depict absolute differences between genes on a chromosome
D) They are practical with species having only a few chromosomes
A mutation caused by a piece of DNA breaking away from its chromosome and becoming attached to a non homologous chromosome is called what?
A change in a gene due to damage or being copied incorrectly is called what?
A mutation
Are the effects of mutation helpful, harmful, or neutral?
All of the above
A diagram in which several generations of a family and the occurrence of certain genetic characteristics are shown is called a what?
A family record that indicated the occurrence of a trait is called a what?
Which of the following traits in controllable by multiple alleles in humans?
A) Sickle cell anemia
B) Blood type
C) Hemophilia
D) Pattern baldness
What would be the blood type of a person who inherited an A allele from one parent and an O allele from the other?
type A
Which of the following describes hemophilia?
A)Multiple-allele trait
B) Dominant trait
C) Sex-linked trait
D) Codominant trait
In humans, the risks of passing on a genetic disorder to one's child can be assessed by what?
Analysis of a pedigree, Prenatal testing, and genetic counseling
Genetic counseling is a process that does what?
Helps identify parents at risk for having children with genetic disorders, assists parents in deciding whether or not to have children, and uses a family pedigree.
While studying several generations of a particular family, a geneticist observed that a certain disease was found equally in males and females and that all children who had the disease had parents who also had the disease. The gene coding for this disease is probably?
Autosomal dominant
If both parents carry the recessive allele that causes custic fibrosis, the chance that their child will develop the disease is what?
One in four.
If a characteristic is sex-linked, it:
A)Occurs most commonly in males
B) Occurs only in females
C) Can never occur in females
D) Is always fatal
Since the allele for colorblindness is located on the X chromosomes, colorblindness:
A) Can't be inherited
B) Occurs only in adults
C) is sex-linked
D) None of the above
How many chromosomes do people with down syndrome have?
47 chromosomes
Trisomy is a mutation that results in a cell having an extra what?
What happens when nondisjunction occurs?
A gamete will receive too many or too few homologues of a chromosome
In humans the genotype XX, results in a _______.
Linked genes can be separated from eachother in meiosis if ___________ occurs.
When traits do not appear according to the expected ratio in offspring, ________ may have occured.
When a piece of chromosome attaches itself to a nonhomologous chromosome, the resulting mutation is called a ________.
A mutation in which a piece of chromosome is lost during meiosis is called a ___________.
A change in an organism's DNA is called a _______________.
Spontaneous changes in genetic material are called _________________.
Identifying patterns of inheritance within a family over several generations is possible by studying a diagram called a ___________.
___________ technology is making it possible to cure genetic diseases.
A person who is herterozygous for a recessive disorder is called a ____________.
By studying a _________, genetic counselors can study how a trait was inherited over several generations.
A genetic disorder resulting in defective blood clotting is _____________.
A genetic disorder in which an individual lacks and enzyme responsible for converting the amino acid phenylalanine into the amino acid thymine is called __________________________.
PKU, phenylketonuria
A trait that is determined by a gene that is found only on the X chromosome is said to be _________________.
In humans, the genetic disorder caused by an extra chromosome 21 is called ____________.
Down syndrome
The failure if replicated chromosomes to separate is called ______________.
What are X-linked genes?
Genes found on the X chromosome
What are Y-linked genes?
Genes found on the Y chromosome
What is sex lineage?
The presence of a gene on a sex chromosome
What are linkage groups?
The group of genes located on one chromosome
What is a chromosome map?
A diagram that shows the linear sequence of genes on a chromosome
What are 3 different types of mutations?
Germ-cell mutations, somatic mutations, and lethal mutations
Where so germ-cell mutations occur?
They occur in an organism's germ cells (gametes), do not affect the organism
What are somatic mutations?
Mutations that take place in an organism's body cells and can therefore affect the organism
What are lethal mutations?
Mutations that cause death, often are before birth
What are chromosome mutations?
Mutations that either are changes in the structure of a chromosome or the loss of an entire chromosome
What's a deletion?
Is the loss of a piece of chromosome due to chromosomal breakage
What is an inversion?
Is a chromosome mutation in which a chromosomal segment breaks off and then reattaches in reverse orientation to the same chromosome
What is translocation?
Is a chromosome mutation in which a chromosome piece breaks off and reattaches to another, non homologous chromosome
What may gene mutations involve?
large segments of DNA or a single nucleotide within a codon
What is a point mutation?
Is the substitution, or removal of a single nucleotide
In point mutations, what are substitutions?
When one nucleotide in a codon is replaced with a different nucleotide, resulting in a new codon
What causes the genetic disorder of sickle cell anemia?
Caused by a point mutation that substitutes adenine for thymine in a single DNA codon. This substitution results in a defective form of the protein hemoglobin
What is a frame-shift mutation?
When an addition or deletion of a single nucleotide causes the remaining codons to be incorrectly grouped
What are genetic disorders?
Are diseases or debilitating conditions that have a genetic basis
What are single-allele traits?
Traits that are controlled by a single allele of a gene
What is Huntington's disease?
Disease caused by a dominant allele located on an autosome and is therefore said to show an autosomal-dominant pattern of inheritance
What is a genetic marker?
Is a short section of DNA that is known to have a close association with a particular gene located nearby
What are multiple-allele traits?
Traits that are controlled by three or more alleles of the same gene that code for a single trait
What is an example of something that is controlled by 3 or more alleles?
the ABO blood groups
What are polygenic traits?
A trait that is controlled by 2 or more genes
What are some examples of polygenic traits?
Skin color, eye color, human height, foot size
What are 3 X-linked traits?
Colorblindness, hemophilia, and Duchenne muscular dystrophy
WHat is Duchenne muscular dystrophy?
a form of muscular dystrphy that weakens and progressively destroys muscle tissue
What is a sex-influenced trait?
A trait with the presence of male or female sex hormones, which influence the expression of certain human traits
In a sex-influenced trait, do males and females have the same or different phenotypes?
What is monosomy?
Is when a zygote with 45 chromosomes have only one particular copy of a chromosome
What is trisomy?
Is when a zygote with 47 chromosomes have three copies of a particular chromosome
Are abnormalities with chromosomal numbers lethal
Yes, they often are
What is genetic screening?
Is an examination of a person's genetic makeup
What is genetic counseling?
A form of medical guidance that informs them about problems that could affect their offspring
What happens during amniocentesis?
The physician removes a small amount of amniotic fluid from the amnion. Then about 16 weeks into the pregnancy, fetal cells and proteins can then be analyzed and a karyotype can also be prepared
What happens during choronic villi sampling?
physician takes a sample of the chorionic villi. The villi will soon have the same genetic makeup as the fetus. Tissue samples from the villi can then be used to produce a karyotype
What is PKU?
A genetic disorder in which the body cannot metabolize the amino acid phenylalanine. This then causes severe brain damage