Biology Exam Ii

Front 1

How do monozygotic twins compare genetically?

Back 1

Monozygotic twinsare derived from one sperm and one egg and, therefore, are 100% geneticallyidentical.

Front 2

True orfalse: All of the genes in each cell in the body are active and produceproteins.

Back 2

False. Althougheach cell contains the same genes, some of these genes are expressed whileothers are not.

Front 3

Name thesteps of the human life cycle

Back 3

• The zygote eventually becomes the fetus.

• Cell differentiation produces the various structures of the human body.

• Billions of cells are eventually produced, each having the same genetic information.

• Sperm and egg join through the process of fertilization.

Front 4

If several specific traits exist in an individual, which situation would increase the number of genetically unique gametes produced?

Back 4

Many of the alleles for the traits are on different chromosomes. If the alleles are on different chromosomes, they will assort independently during gamete formation.

Front 5

Which cell would contain a single copy of each of the human body's 23 chromosomes?

Back 5

sperm cell. Sperm cells are haploid, so they have only one chromosome of each homologous pair.

Front 6

Which processes increase genetic diversity?

Back 6

• segregation

• random fertilization

• crossing over

• Mutation

Front 7

Which process does not increase genetic diversity?

Back 7

Cell differentiation occurs after meiosis and fertilization, so it does not change the genetic makeup of an individual.

Front 8

True or false: Human cells contain more genetic information than the cells of any other organism.

Back 8

False. Some nonhuman organisms have cells that contain many more chromosomes than human cells do.

Front 9

How do these embryo’s compare genetically?

Back 9

• 100 % genetically identical for monozygotic twins

• 50 % genetically identical for dizygotic twins

Front 10

Why might a dysfunctional gene affect one type of cell in the body, but not other types of cells?

Back 10

•Cells express only the genes required for their particular activities.

• Cells only use the genes they need for their particular function; for example, only eye cells express rhodopsin.

Front 11

After a human egg and sperm fuse in fertilization, what is the immediate result?

Back 11

• A zygote is the result of fused gametes.

Front 12

How do dizygotic twins compare genetically?

Back 12

• Dizygotic twins are derived from two different sperm and two different eggs and thus are genetically no more similar than siblings born at different times.

Front 13

What does homozygous dominant look like?

Back 13

• DD

Front 14

What does heterozygous dominant look like?

Back 14

• Dd

Front 15

What does homozygous recessive look like?

Back 15

• dd

Front 16

In a pea plant, yellow seeds are dominant and green seeds are recessive. A pea plant that is homozygous dominant for seed color is crossed with a pea plant that is heterozygous. What color seeds are possible in the offspring?

Back 16

Because the cross would yield only homozygous dominant and heterozygous offspring, all offspring would have the dominant phenotype: yellow seeds.

Front 17

Two carriers of the cystic fibrosis gene conceive a child. What is the probability that their child would have cystic fibrosis?

Back 17

In a cross between two heterozygotes, 25% of offspring are likely to have the disease.

Front 18

A woman with one allele for Huntington's disease marries a man who also has one allele for the disease. What is the probability that their child will have the disease?

Back 18

Since this disease is caused by a dominant allele, a child that inherits even one allele will get the disease. In a cross between two heterozygotes, there is a 75% probability that a child will receive at least one allele for Huntington's disease.

Front 19

Which expression directly represents a genotype?

Back 19

• FFGg

Front 20

Name three quantative traits in humans?

Back 20

• height, weight and blood pressure.

Front 21

For the trait of weight, which population is likely to have the most variability?

Back 21

• an auditorium of parents

• A random selection of parents is likely to show high variability in weight.

Front 22

In a flock of chickens, the heritability of egg weight is found to be 0.35. What conclusions can be made about this data?

Back 22

• Heritability measures the effect of genes on the variability of a quantitative trait in a population. A heritability of 0.35 means that genetics accounts for 35% of the variation in egg weight among the chickens, whereas 65% of the variation is due to environmental factors.

Front 23

How is the phenotype of a quantitative trait expressed?

Back 23

• Quantitative traits show continuous variation, which means that there is a large range of phenotypes in a population

Front 24

If the heritability of intelligence in a population of mice is 0.95, what does this tell us?

Back 24

• Heritability measures the genetic influence on a trait; 0.95 heritability of intelligence means that 95% of the variation in intelligence in this mouse population is attributable to genetics.

Front 25

What is one difference between calculating heritability of traits in cattle and heritability of traits in human populations?

Back 25

• Manipulating human environments and reproduction is not practical or ethical.• To calculate heritability in human populations, researchers must perform correlations among individuals who have varying degrees of genetic similarity.

Front 26

To which group are measures of heritability applied?

Back 26

• Heritability is a measure of the proportion of variation of a quantitative trait in a particular population that is due to genetics.

Front 27

How is codominance expressed?

Back 27

• Both alleles are expressed in the phenotype of the heterozygote.• In codominance, neither allele is dominant to the other, so both are expressed.

Front 28

What pattern of inheritance produces offspring with orange flowers from a cross between a plant with yellow flowers and a plant with red flowers?

Back 28

• Incomplete dominance produces a phenotype in the heterozygote that is in between that of the two homozygotes.

Front 29

The offspring of a horse with a black coat and a horse with a white coat is a horse with patches of black and white in its coat. What pattern of inheritance for coat color is found in these horses?

Back 29

• codominance.

• Both alleles are equally expressed for the codominant trait in the heterozygote.

Front 30

What are the blood types?

Back 30

• IA is the blood type A allele

• IB is the blood type B allele

• i is the blood type O allele.

• IA and IB are codominant, while i is recessive

Front 31

Jim has type B blood. Christa has type O blood. Josh and Kevin have type B blood. Pradeep has type AB blood. What possibilities exist for blood donations between these people?

Back 31

• Josh, Kevin, and Jim could be blood donors to Pradeep.

• Because Pradeep has type AB blood, his blood would not create antibodies to any blood type

Front 32

If an Rh– mother has an Rh+ baby, what are the possible genotypes of the baby's father?

Back 32

• Rh+/Rh+ or Rh+/Rh–

• The father could be homozygous dominant or heterozygous to have an Rh+ baby with an Rh– mother

Front 33

How do incomplete dominance and codominance compare?

Back 33

• In codominance, the heterozygote expresses both phenotypes; in incomplete dominance, the heterozygote shows an intermediate phenotype.

Front 34

A breeder of Cochin chickens breeds a group of white-feathered hens with a black-feathered rooster. The resulting chicks all develop gray feathers. If feather color is controlled by a single pair of genes, what genetic phenomenon is occurring?

Back 34

• The black and white alleles are incompletely dominant.

Front 35

What sex chromosome would you get from your father?

Back 35

• Y from dad

• X from mom

Front 36

What pair of chromosomes found in a human cell determine the gender of the individual?

Back 36

• A human body cell has one pair of sex chromosomes and 22 pairs of autosomes (nonsex chromosomes).

Front 37

A woman has a disorder, and her husband does not. The disorder is inherited by all of their male offspring, but none of their female offspring. Their children marry spouses who are normal. When their daughters have children, half of their sons and none of their daughters have the disorder. When their sons have children, none of their children inherit the disorder. What mode of inheritance does this disorder follow?

Back 37

• sex-linked recessive.

Front 38

What type of chromosomes found in human cells comprise 22 pairs and do not determine the gender of the individual?

Back 38

• Autosomes are the non-sex chromosomes; each human cell contains 22 pairs of autosomes and 2 sex chromosomes.

Front 39

What type of genetic disorder would show mostly males being affected on a pedigree diagram?

Back 39

• X-linked recessive diseases often show up in males, because they only need one copy of the allele for the disease to be affected.

Front 40

The root meta- means what?

Back 40

change or between

Front 41

The root meio- means what?

Back 41

to make smaller

Front 42

The root mito-means what?

Back 42

a thread

Front 43

The root onco- means what?

Back 43

cancer.

Front 44

The root proto- means what?

Back 44

prior to or before

Front 45

The root soma- (or -some) means what?

Back 45

a body

Front 46

The root telo- means what?

Back 46

the end or completion.

Front 47

Meiosis is the division of the nucleus that occurs in where?

Back 47

sex cells

Front 48

Telophase is the final stage of what?

Back 48

mitosis.