PRAXIS 2 BIOLOGY CONTENT 5235
EXAM QUESTIONS AND ANSWERS
What is inheritance? - Correct Answers -the process by which characteristics are
passed from one generation to another
Who was Gregor Mendel? - Correct Answers -The father of genetics; studied
relationships between traits expressed in parents and offspring and hereditary factors
causing the expression of these traits.
What is the generation of plants used to perform the first cross called? - Correct
Answers -P1 generation
F1 generation - Correct Answers -first generation of offspring resulting from two P1
crosses
What are regulatory genes? - Correct Answers -genes that code proteins that determine
functional of physiological events, like growth.
Proteins regulate when other genes start or stop encoding proteins, which produce
specific traits.
What is transduction (bacteria)? - Correct Answers -transfer of genetic material from 1
bacterial cell to another
What is transformation (bacteria)? - Correct Answers -bacterial cells absorb and
incorporate pieces of DNA from environment (usually dead bact. cells).
F2 generation - Correct Answers -generation resulting from cross of 2 F1 crosses
genes - Correct Answers -hereditary factor
How many copies of genes are carried by an individual? - Correct Answers -2 copies of
a gene; copies may differ
dominant gene - Correct Answers -gene that can mask the effect of a recessive gene
recessive gene - Correct Answers -gene that cannot mask the effect of a gene.
Generally 2 copies of a recessive gene are required for the trait to be expressed.
,chromosome - Correct Answers -A threadlike structure of nucleic acids and protein
found in the nucleus of most living cells, carrying genetic information in the form of
genes.
homologous chromosomes - Correct Answers -Corresponding pairs of chromosomes
that carry genes for the same traits. Found in most eukaryotes
gene locus - Correct Answers -position on a homologous chromosome at which the
genes that produce a given trait exist
allele - Correct Answers -different form of a gene. E.g., yellow seeds and green seeds
arise from different alleles of the same gene.
What are the products of meiosis? - Correct Answers -gamete cells with 1/2 the genetic
information of the parents.
What is the Law of Independent Assortment? - Correct Answers -States that paired
chromosomes are separated and sorted independently. As a result, each gamete may
receive one of any number of combinations of each parent's chromosomes.
genotype - Correct Answers -combination of alleles that make a particular trait
phenotype - Correct Answers -trait expressed from the combination of alleles that make
a particular trait.
dominant allele - Correct Answers -allele that masks the effect of its partner allele
recessive allele - Correct Answers -allele that does not produce its trait when present
with a dominant allele.
Punnett square - Correct Answers -notation that allows for the prediction of a genetic
cross.
homozygous trait - Correct Answers -when both alleles for a given gene are the same in
an individual
heterozygous trait - Correct Answers -when both alleles for a given gene are different in
an individual.
monohybrid cross - Correct Answers -a cross between two individuals where only one
trait is considered.
dihybrid cross - Correct Answers -a cross between two individuals where two separate
traits are considered.
,law of segregation - Correct Answers -Mendel's 1st law of inheritance - traits are
expressed from a pair of genes in the individual on homologous chromosomes
What is the Law of Segregation? - Correct Answers -paired
chromosomes/corresponding genes separate and randomly recombine during gamete
formation.
What is the Law of Dominance? - Correct Answers -Mendel's 2nd law of inheritance -
one gene usually expresses itself over the other (one gene is dominant over the other)
What evidence is produced by F1 generation according to the Law of Dominance? -
Correct Answers -The fact that the F1 generation produced no recessive traits is
evidence of law of dominance.
What is the Law of Independent Assortment? - Correct Answers -Mendel's 3rd law of
inheritance - since homologous chromosomes separate and independently sort in
gamete formation, alleles are also separated and independently sorted.
What is incomplete dominance? - Correct Answers -some traits are determined by
genes that are neither dominant nor recessive and instead produce offspring that are a
mix of the 2 parents. EX - red and white flowers produce pink flower
co-dominance - Correct Answers -also known as incomplete dominance
Multiple alleles - Correct Answers -ABO blood group is example. More than 2 choices of
alleles are present. In ABO group, A and B are dominant and O is recessive.
linked traits - Correct Answers -traits that are inherited together. This is exception to law
of independent assortment. Some traits are always inherited together.
What is crossing over? - Correct Answers -During metaphase of meiosis 1 when
homologous chromosomes line up along the center of the dividing cell, some pieces of
the chromosomes break off and move from one chromosome to another. Adds more
variation of traits.
Does crossing over occur for genes that are closer together or farther apart? - Correct
Answers -It is more likely that crossing over occurs between genes that do not lie close
together on a chromosome.
How is gender determined in an organism? - Correct Answers -Gender is determined in
an organism by a particular homologous pair of chromosomes.
polygenetic inheritance - Correct Answers -traits produced from interaction of multiple
sets of genes.
, Examples of polygenic inheritance - Correct Answers -diseases such as diabetes and
heart disease have multiple contributing factors involved in their development in a
person.
Are polygenic traits difficult or easy to map and predict? - Correct Answers -Polygenic
traits are difficult to map and predict because of the varied effects of the different genes
and contributing factors on a specific trait or disease.
Are diseases resulting from genetic disorders rare or common? - Correct Answers -
They are very rare because they are mostly derived from abnormalities of a single gene.
What are autosomal dominant disorders? - Correct Answers -diseases that can affect a
person when only one mutated copy of the gene is present.
What is the frequency of an autosomal dominant disorder in the children of an affected
parent? - Correct Answers -The majority of the time an affected person only has one
affected parent. Each child of an affected person has a 50% chance of inheriting the
mutated gene.
Most common example of autosomal dominant disorder - Correct Answers -
Huntington's disease
What are autosomal recessive disorders? - Correct Answers -Diseases that require 2
copies of the mutated gene to be inherited for a person to be affected.
What is the frequency of autsomal recessive disorders from unaffected parents who are
carriers? - Correct Answers -Affected person may receive one or both of the mutated
genes from unaffected parents. Unaffected parents are carriers and possess one copy
of the mutated gene. Their children have a 25% chance of inheriting the disorder
What are the most common examples of autosomal recessive disorders? - Correct
Answers -Cystic fibrosis and Sickle-Cell Anemia
What is an X-linked dominant disorder? - Correct Answers -a diseases that is caused by
a dominant mutation in a gene on the X chromosome.
What is an example of an X-linked dominant disorder? - Correct Answers -Rett
syndrome and a form of rickets
Do X-linked dominant disorders affect males, females, or both? - Correct Answers -Both
males and females can be affected, but in males the symptoms are often much more
severe and very commonly fatal.
What is the frequency of inheritance of X-linked dominant disorder in female parents? -
Correct Answers -50% in all offspring
EXAM QUESTIONS AND ANSWERS
What is inheritance? - Correct Answers -the process by which characteristics are
passed from one generation to another
Who was Gregor Mendel? - Correct Answers -The father of genetics; studied
relationships between traits expressed in parents and offspring and hereditary factors
causing the expression of these traits.
What is the generation of plants used to perform the first cross called? - Correct
Answers -P1 generation
F1 generation - Correct Answers -first generation of offspring resulting from two P1
crosses
What are regulatory genes? - Correct Answers -genes that code proteins that determine
functional of physiological events, like growth.
Proteins regulate when other genes start or stop encoding proteins, which produce
specific traits.
What is transduction (bacteria)? - Correct Answers -transfer of genetic material from 1
bacterial cell to another
What is transformation (bacteria)? - Correct Answers -bacterial cells absorb and
incorporate pieces of DNA from environment (usually dead bact. cells).
F2 generation - Correct Answers -generation resulting from cross of 2 F1 crosses
genes - Correct Answers -hereditary factor
How many copies of genes are carried by an individual? - Correct Answers -2 copies of
a gene; copies may differ
dominant gene - Correct Answers -gene that can mask the effect of a recessive gene
recessive gene - Correct Answers -gene that cannot mask the effect of a gene.
Generally 2 copies of a recessive gene are required for the trait to be expressed.
,chromosome - Correct Answers -A threadlike structure of nucleic acids and protein
found in the nucleus of most living cells, carrying genetic information in the form of
genes.
homologous chromosomes - Correct Answers -Corresponding pairs of chromosomes
that carry genes for the same traits. Found in most eukaryotes
gene locus - Correct Answers -position on a homologous chromosome at which the
genes that produce a given trait exist
allele - Correct Answers -different form of a gene. E.g., yellow seeds and green seeds
arise from different alleles of the same gene.
What are the products of meiosis? - Correct Answers -gamete cells with 1/2 the genetic
information of the parents.
What is the Law of Independent Assortment? - Correct Answers -States that paired
chromosomes are separated and sorted independently. As a result, each gamete may
receive one of any number of combinations of each parent's chromosomes.
genotype - Correct Answers -combination of alleles that make a particular trait
phenotype - Correct Answers -trait expressed from the combination of alleles that make
a particular trait.
dominant allele - Correct Answers -allele that masks the effect of its partner allele
recessive allele - Correct Answers -allele that does not produce its trait when present
with a dominant allele.
Punnett square - Correct Answers -notation that allows for the prediction of a genetic
cross.
homozygous trait - Correct Answers -when both alleles for a given gene are the same in
an individual
heterozygous trait - Correct Answers -when both alleles for a given gene are different in
an individual.
monohybrid cross - Correct Answers -a cross between two individuals where only one
trait is considered.
dihybrid cross - Correct Answers -a cross between two individuals where two separate
traits are considered.
,law of segregation - Correct Answers -Mendel's 1st law of inheritance - traits are
expressed from a pair of genes in the individual on homologous chromosomes
What is the Law of Segregation? - Correct Answers -paired
chromosomes/corresponding genes separate and randomly recombine during gamete
formation.
What is the Law of Dominance? - Correct Answers -Mendel's 2nd law of inheritance -
one gene usually expresses itself over the other (one gene is dominant over the other)
What evidence is produced by F1 generation according to the Law of Dominance? -
Correct Answers -The fact that the F1 generation produced no recessive traits is
evidence of law of dominance.
What is the Law of Independent Assortment? - Correct Answers -Mendel's 3rd law of
inheritance - since homologous chromosomes separate and independently sort in
gamete formation, alleles are also separated and independently sorted.
What is incomplete dominance? - Correct Answers -some traits are determined by
genes that are neither dominant nor recessive and instead produce offspring that are a
mix of the 2 parents. EX - red and white flowers produce pink flower
co-dominance - Correct Answers -also known as incomplete dominance
Multiple alleles - Correct Answers -ABO blood group is example. More than 2 choices of
alleles are present. In ABO group, A and B are dominant and O is recessive.
linked traits - Correct Answers -traits that are inherited together. This is exception to law
of independent assortment. Some traits are always inherited together.
What is crossing over? - Correct Answers -During metaphase of meiosis 1 when
homologous chromosomes line up along the center of the dividing cell, some pieces of
the chromosomes break off and move from one chromosome to another. Adds more
variation of traits.
Does crossing over occur for genes that are closer together or farther apart? - Correct
Answers -It is more likely that crossing over occurs between genes that do not lie close
together on a chromosome.
How is gender determined in an organism? - Correct Answers -Gender is determined in
an organism by a particular homologous pair of chromosomes.
polygenetic inheritance - Correct Answers -traits produced from interaction of multiple
sets of genes.
, Examples of polygenic inheritance - Correct Answers -diseases such as diabetes and
heart disease have multiple contributing factors involved in their development in a
person.
Are polygenic traits difficult or easy to map and predict? - Correct Answers -Polygenic
traits are difficult to map and predict because of the varied effects of the different genes
and contributing factors on a specific trait or disease.
Are diseases resulting from genetic disorders rare or common? - Correct Answers -
They are very rare because they are mostly derived from abnormalities of a single gene.
What are autosomal dominant disorders? - Correct Answers -diseases that can affect a
person when only one mutated copy of the gene is present.
What is the frequency of an autosomal dominant disorder in the children of an affected
parent? - Correct Answers -The majority of the time an affected person only has one
affected parent. Each child of an affected person has a 50% chance of inheriting the
mutated gene.
Most common example of autosomal dominant disorder - Correct Answers -
Huntington's disease
What are autosomal recessive disorders? - Correct Answers -Diseases that require 2
copies of the mutated gene to be inherited for a person to be affected.
What is the frequency of autsomal recessive disorders from unaffected parents who are
carriers? - Correct Answers -Affected person may receive one or both of the mutated
genes from unaffected parents. Unaffected parents are carriers and possess one copy
of the mutated gene. Their children have a 25% chance of inheriting the disorder
What are the most common examples of autosomal recessive disorders? - Correct
Answers -Cystic fibrosis and Sickle-Cell Anemia
What is an X-linked dominant disorder? - Correct Answers -a diseases that is caused by
a dominant mutation in a gene on the X chromosome.
What is an example of an X-linked dominant disorder? - Correct Answers -Rett
syndrome and a form of rickets
Do X-linked dominant disorders affect males, females, or both? - Correct Answers -Both
males and females can be affected, but in males the symptoms are often much more
severe and very commonly fatal.
What is the frequency of inheritance of X-linked dominant disorder in female parents? -
Correct Answers -50% in all offspring
