bio study knowt

Genetics is defined as the study of:

heredity

Which one of the following statements most accurately summarizes the state of genetically modified foods in the U.S. today?

Their use is widespread but controversial.

The decline of the eugenics movement in the U.S. in the early 20th century resulted from:

its misuse for social and political purposes by the Nazis

Which one of the following statements about eugenics is UNTRUE?

It was founded by Charles Darwin.

(T/F) Since Mendel discovered that parents' traits are not blended in their offspring, crossing a red flower with a white flower and obtaining pink progeny is impossible.

False

Dolly the sheep is famous for:

being the first cloned animal

Which one of the following research projects in genetics would be an example of basic research?

research on what causes genes to turn on and off

Gene therapy can best be described as:

the insertion of normal genes to act in place of mutant genes

Mendel's work on the transmission of genes in pea plants is applicable to:

all plants and animals, including humans

Modern biotechnology has made it possible to

test an individual's entire genome for predispositions to heart disease, diabetes, and cancer; produce human embryos in a laboratory dish; test adults to see if they are at risk for having children with a genetic disease; diagnose genetic disorders in fetuses, before birth

Which one of the following best summarizes how transmission genetic studies are done differently with humans than with other organisms?

Human geneticists study the inheritance of traits in existing families and Human geneticists perform pedigree analyses.

The purpose of preparing karyotypes in clinical settings can best be stated as:

to reveal chromosome abnormalities

(T/F) A nucleotide consists of a base, a sugar, and a phosphate group.

True

Gregor Mendel

claimed that each individual carries a pair of "factors" for a given trait; began the scientific study of heredity; was a monk; cross-bred pea plants with different traits

(T/F) Gene variations, such as whether one is brown-eyed or blue-eyed, would be revealed in a karyotype.

False

Which one of the following statements about a gene is TRUE?

It is the structural and functional unit of genetics.; When activated, it is used to make a protein molecule.; It is a string of nucleotides in a DNA molecule.

(T/F) Mendel proposed that individuals have two copies of each gene ("factor") which separate from each other during sperm and egg formation.

True

DNA microarrays (DNA chips) are used to:

screen an individual's entire genome

Which one of the following is the most accurate description of the pedigrees used in human genetics?

family tree charts showing who has/had a particular trait

One of the properties of genes is that they can "recombine." This refers to their ability to:

move from one chromosome to another

Formation of eggs and sperm are the same in what way(s)?

the way chromosomes behave during meiosis

In the cell cycle, the G1 phase represents:

a period of growth

(T/F) Chromatid is the term for a chromosome before it is duplicated.

False

A cell that could not form spindle fibers could not perform:

mitosis or meiosis

Gaucher disease is associated with abnormality of which part of the cell?

lysosomes

In meiosis, the centromeres divide at:

anaphase II

(T/F) Mitotic divisions reduce the number of chromosomes found in daughter cells.

False

During meiosis in an organism where 2n = 6, how many chromatids will be present in a cell at the beginning of meiosis II?

6

If an organism has a diploid chromosome number of 4, how many chromosome pairs will be visible in meiosis?

2

(T/F) Autosomal chromosome pairs are homologous, whereas the sex chromosome pair in males is not.

True

(T/F) Crossing over occurs between chromatids of chromosome pairs.

True

(T/F) Cytokinesis usually occurs just after mitosis.

True

A cell in G0 state is a cell:

that never divides

Haploid gametes contain:

half the 2n chromosome number

Autosomes represent:

all chromosomes other than the sex chromosomes

all chromosomes other than the sex chromosomes

Interphase.

Centromeres:

both connect sister chromatids and attach chromosomes to spindle fibers

(T/F) A polar body, once formed, has no further function and dies.

True

Endoplasmic reticulum is involved in:

transport of materials throughout the cell

(T/F) "Random Assortment" of homologous chromosomes is partially responsible for our genetic diversity.

True

Independent assortment means that:

The segregation of one gene pair occurs as if no other gene pair was present.

In a monohybrid cross with complete dominance, the F2 offspring should contain:

two different phenotypes and three different genotypes

In the monohybrid crosses, Mendel deduced that one trait was recessive because:

That trait was not present in the F1 and reappeared in the F2.

A locus is best defined as:

the chromosomal location of a gene

In the cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds , what are the genotypes of the gametes that the F1 can form?

SY, Sy, sY, sy

The Bombay gene affects expression of the ABO blood type. What would be the blood type of a person with the genotype hhIAIB?

Type O

In a cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds, the offspring were all smooth and yellow. What is the genotype of the F1 plants?

SsYy

Pedigrees:

can identify those at risk for a disease; provide information on the patterns of inheritance of a trait; can be used to deduce the genotypes of parents; can identify those at risk for transmitting a disease

(T/F) Chi square tests are used to determine whether a cross has been correctly constructed and analyzed.

False

In a cross involving incomplete dominance:

The phenotypic ratio and genotypic ratio in the F2 are identical.

In a pedigree, a person whose symbol is filled in and who is associated with the roman numeral II:

is affected by the trait and in the second generation

In the ABO multiple allele system, there are the following combinations of genotypes and phenotypes:

6 genotypes, 4 phenotypes

In a situation with codominant inheritance:

The principles of Mendelian inheritance are intact.; Independent assortment can predict the genotypes and phenotypes of the offspring.; There is no recessive phenotype.; Each allele is fully and completely expressed.

Alternate forms of a gene are best described as:

alleles

Organisms with similar phenotypes:

may have different genotypes

(T/F) A person with genotype LMLN has the phenotype (blood type) M.

False

In the F2 generation of a cross between true-breeding plants bearing smooth, yellow seeds and a true-breeding plants with wrinkled, green seeds, what proportion of the plants will have the genotype SsYy?

4/16

A pea plant with yellow peas is crossed with a pea plant that has green peas. The offspring include both yellow-pea and green-pea plants. The original plant with yellow peas must, therefore, have what genotype?

Yy

(T/F) Dominant traits are expressed only in the heterozygous state.

False

A chi square test is done to determine:

how closely actual results of a cross match the expected results

Parents with normal pigmentation have an albino child. What is the chance that their next child will have normal pigmentation?

75 percent

Hemophilia was a significant issue in the life of

the last royal family of Russia

If all one knows about a genetic trait is that everyone known to have it is male, the pattern of inheritance must be

X-linked recessive; Y-linked

(T/F) Mendel's laws apply to all sexually reproducing organisms and thus the basic method of genetic analysis in humans and other organisms is the same.

False

Y-linked traits are:

carried only by males and transmitted only to males; hemizygous traits

In autosomal dominant inheritance:

Two affected individuals may have unaffected children.

Almost all cases of cystic fibrosis arise as the result of mating between two unaffected parents. Why?

Homozygotes usually die before reproduction.

Dystrophin is a protein that normally:

stabilizes the membrane of muscle cells during contraction

Which one of the following is NOT characteristic of people with Marfan disease?

shortness of breath

The name "cystic fibrosis" refers to the damage done by this disease to what organ?

pancreas

Which of the following patterns of inheritance is non-Mendelian?

maternal

A child is born with a lethal dominant allele. This would seem to be impossible since either parent, had they possessed this allele, would have suffered its lethal effects. What is a possible explanation?

The allele could have varying expressivity and not always be lethal.; The child's allele is a spontaneous mutation which neither parent had to deal with.; The allele could have delayed onset.

What is "OMIM?"

a catalog of human genetic traits

Two phenotypically normal parents have six children. One daughter and one son have a genetic disease. This would be the expected situation for:

Cystic fibrosis

If a trait is inherited in an autosomal recessive fashion, which of the following is not true?

Two affected individuals can have an unaffected child.

What do Huntington Disease and Marfan disease have in common?

They are both caused by dominant alleles.

If a man expresses an X-linked recessive trait, we can draw the following conclusion:

His mother was heterozygous or homozygous for the trait.

Approximately how many Y-linked genes have been discovered?

60

Which one of the following is NOT usually a symptom of cystic fibrosis?

problems with hearing and vision

Camptodactyly

shows varying expressivity; shows less than complete penetrance; causes bent, immobile little fingers; is inherited as a dominant trait

Twins are said to be concordant for a trait when:

Both twins exhibit the trait.

In what way are "complex" traits different from "multifactorial" traits?

In complex traits the contributions of genes and environment are undefined.

(T/F) For threshold traits the liability for a genetic disorder is distributed among individuals in a normal curve.

True

Genome scans have been used to search for genes for obesity in humans. What has been discovered?

several genes on several chromosomes

Most evidence indicates that skin color is controlled by how many gene pairs?

three to four

If a trait has a heritability of 1.0, this means that:

All variation in the population is caused by genotypic differences.

People with threshold types of birth defects are more likely to have children with the same defect if

they are older when they have children; the defect occurs more often in one sex

The phenomenon of regression to the mean is observed in traits that are:

multifactorial

Which of the following is not characteristic of continuous variation?

Only a single gene pair contributes to the phenotype.

In continuous traits such as height, crossing a very tall and very short organism will produce an F1 that is:

all intermediate in height

Folate is a vitamin that is a key nutritional factor in the expression of what birth defect?

spina bifida

In a certain population with a mean IQ of 100, the heritability of IQ was measured at 0.6. A chapter of Mensa in this population has an average IQ of 140. If they are otherwise typical of their population, about how many of their IQ points can be attributed to their genes?

24

Clubfoot and cleft palate are traits:

that have discontinuous distribution; that are multifactorial; that are congenital birth defects; whose distribution can best be explained by the threshold model

Many studies have been conducted on the heritability of obesity. With fairly strong consistency they indicate that the heritability of this trait is about:

.7

(T/F) Multifactorial traits are always continuously distributed.

False

The tall and short phenotypes in pea plants are examples of:

discontinuous traits

(T/F) The additive model for polygenic inheritance proposes that the genes controlling a trait are all on one chromosome.

False

It has frequently been observed that musical ability "runs in families" (the Joneses and Smiths, not just the Bachs). This indicates that musical ability is mainly:

None of these determinations can be made from these facts alone.

(T/F) According to the threshold model, for a family in which a disorder occurs, the risk of the disorder decreases as relatedness decreases.

True

The story about King Frederick Williams' failure to breed increasingly tall men to serve in the Potsdam Guards is an example of what concept in genetics?

regression to the mean