Genetics Unit 1 Connect

Select all of these that are true regarding inheritance of a disease caused by homozygosity for a recessive allele. Multiple select question. -Each child of two unaffected parents (both carriers) has a 25% chance of being affected. -All offspring of two affected individuals will always be affected. -The trait is usually present in every generation. -If two parents are blood relatives they have a higher chance than two unrelated parents of having affected children. -Affected individuals always have at least one affected parent.

-Each child of two unaffected parents (both carriers) has a 25% chance of being affected. -All offspring of two affected individuals will always be affected. -If two parents are blood relatives they have a higher chance than two unrelated parents of having affected children.

From the list below, choose all that are correctly written genotypes used by human geneticists. Multiple select question. -HD+ CF+ -AA bb -HD+HD -CF+CF+

-HD+HD -CF+CF+

What information can be obtained from a human pedigree? Multiple select question. -The type of mutation that produced a variant allele -Where a gene is located on a chromosome -How a trait is inherited -A family history of genetic traits

-How a trait is inherited -A family history of genetic traits

Select the events that occur during prophase of mitosis. Multiple select question. -The chromosomes separate. -The centrosomes move apart. -The centrosomes are replicated. -The nucleolus becomes less visible. -The chromatin condenses into more compact structures.

-The centrosomes move apart. =The nucleolus becomes less visible. -The chromatin condenses into more compact structures.

A normal human somatic cell carries ______ pairs of chromosomes for a total of ______.

23 ; 46

Insert a number into the blank: Most human somatic cells contain a total of ________ chromosomes.

46

What is chromatin?

A complex between DNA and proteins that is found in eukaryotic cells

What is the basic unit of biological information?

A gene

What is epistasis?

A gene interaction in which the effects of an allele of one gene mask the effects of the alleles of a second gene

What is a heterogeneous trait?

A trait that can result from a mutation in one of a number of different genes

When you consider only the sex chromosomes, what types of gametes are produced by a female individual of a species with the XY system of sex determination?

All gametes carry a X chromosome.

One form of hereditary deafness is inherited with an X-linked recessive allele. What can be expected for the offspring of a deaf mother and a father with normal hearing?

All of the sons will be deaf and all of the daughters will have normal hearing.

What ensures that cell cycle events occur in the proper sequence?

Checkpoints

Which description matches the appropriate pattern involving two genes?

Epistasis-Expression of the alleles of one gene is masked by alleles of a different gene. Reciprocal recessive epistasis-Two parents with the same recessive phenotype produce only offspring with a different phenotype. Gene redundancy- A specific phenotype is produced when only one of two genes is functional.

Match each allele in the ABO blood type system in humans with the enzyme it specifies.

IA- Specifies an enzyme that adds sugar A IB-Specifies an enzyme that adds sugar B i-Does not specify a functional sugar-adding enzyme

Which of the following phenomena expand (i.e., increase) the number of phenotypic classes among the F2 offspring of a cross? Multiple select question. Incomplete dominance Codominance Dominant epistasis Recessive epistasis Redundant gene action

Incomplete dominance Codominance

Match the genes A, K, and E with their role in the determination of dog coat color.

K- Specifies a protein that turns the switch protein to the on position resulting in the production of eumelanin A- Specifies a protein that turns the switch protein to the off position resulting in the production of pheomelanin E- Specifies a protein that acts as a switch that determined which pigment is produced by a melanocyte

Select the events that occur during mitosis. Multiple select question. -Tetrads align on the metaphase plate of the cell -Kinetochores begin attaching to spindle fibers -Sister chromatids separate, and move to opposite poles -Pairing and synapsis of homologous chromosomes -Chromosomes condense, and nuclear envelope breaks down

Kinetochores begin attaching to spindle fibers Sister chromatids separate, and move to opposite poles Chromosomes condense, and nuclear envelope breaks down

The results of an experiment can be skewed by random chance. Why were the results of Mendel's numerous crosses so consistent?

Mendel analyzed large numbers of plants.

Which of the following statements about mitosis and meiosis of humans is true?

Mitosis produces two diploid daughter cells, while meiosis produces four haploid daughter cells.

In one of his experiments, Mendel started by crossing pure-breeding tall pea plants with pure breeding short pea plants. These pure breeding plants are considered the _____ generation.

P

The two ends of the Y chromosome that are homologous with the ends of the X chromosome are called ___________ regions.

PAR

During what stage of meiosis II does the nuclear envelope break down?

Prophase II

The expected outcome of flipping a coin is 50% heads and 50% tails. However, in a given study, the coin toss yielded heads 65% of the time and tails 35% of the time. What accounts for this discrepancy?

Random chance

Match each type of gene interaction with the phenotypic ratio observed in the F2 generation of a dihybrid cross.

Recessive epistasis- 9:3:4 Dominant epistasis- 12:3:1 Reciprocal recessive epistasis- 9:7 Redundant gene action- 15:1

Which of the following statements accurately describes gametogenesis in sexually reproducing animals?

Specialized diploid cells divide by meiosis to produce haploid cells.

Two pure-breeding plants are crossed with one another. The first plant is homozygous for allele A1 and has white flowers. The second plant is homozygous for allele A2 and has blue flowers. The A1A2 hybrids all have blue flowers. Which allele is dominant?

The A2 allele is dominant to A1.

Which of the following statements about the sickle-cell mutation is an example of its pleiotropic effects?

The mutation causes changes in blood cell shape and confers resistance to malaria.

A pure-breeding tall plant is crossed with a pure-breeding short plant. The hybrid offspring from this cross are all short. Which allele of the gene for height is dominant?

The short allele is dominant.

Which of the following would be classified as the P generation?

True-breeding parents that are crossed

An allele that specifies a normally functioning gene in a human is typically written as the name of the gene followed by

a superscript +

A nucleus is ____.

an organelle found in eukaryotic cells that contains the hereditary material

Many food crops, such as corn and potatoes, were developed by using seed from the best tasting plants for the next planting in a process called ____________ selection.

artificial

During prophase of mitosis, chromosomes __________ into discrete structures. Furthermore, the two ____________ separate moving towards the poles and the mitotic ___________ begins to form.

condense centrosomes spindle

The genetic composition of an individual is the ______.

genotype

What term describes an individual's combination of alleles?

genotype

Cells that are destined to undergo meiosis and produce gametes are called ________ cells.

germ

Hemophilia is an X-linked recessive trait. One of the conditions that must be met for a female child to have hemophilia is that ______.

her father must have hemophilia

In humans, the male is known as the _________ sex, because males can make two types of gametes: one type of sperm carries only the X chromosome, and another type carries the Y chromosome.

heterogametic

Because deafness can result from a mutation in one of many different genes, it is considered a(n) ___________ trait.

heterogeneous

Had it been widely recognized, Mendel's work could have helped Darwin explain _____.

how variation persists in natural populations

Geneticists often study inbred populations of experimental organisms to study specific traits. The purpose of using inbred populations is to

limit the number of variables being studied.

In mammals, the SRY gene on the Y chromosome determines ______, whereas lack of the SRY gene results in a ______ organism.

maleness, female

Redundant genes are genes that _____.

may specify nearly identical proteins with the same function

A change in the genetic material is called a(n)

mutation

Trisomies occur due to _____.

nondisjunction

When homologs of a chromosome pair do not segregate during meiosis I, this is known as

nondisjunction

The _________ of a eukaryote is the organelle that contains most of the genetic material found in the cell.

nucleus

The PAR1 and PAR2 regions are found _____.

on both the X and Y chromosomes

Pleiotropy is a situation in which ______.

one gene affects several different characteristics

Oogenesis in humans takes place in the ______.

ovaries

The phenomenon in which one gene affects many traits is called

pleiotropy

The product rule can be used to ______.

predict the probability of two or more independent events

-fertilization is a cross in which the pollen and egg come from the same plant.

self

Spermatogenesis takes place in the ______.

testes

Select all that apply Which of the following statements about Mendel's immediate contribution to genetics are true? -Because Mendel was a monk and not a university professor, his work did not receive much attention from other scientists. -Sheep breeders attempted to replicate Mendel's findings. -Mendel coined the term 'chromosome' to describe the factors that transmit genes. -The scientist Charles Darwin repeated Mendel's experiments in other organisms to develop his theory of evolution. -Mendel's data was largely ignored for more than 30 years.

-Because Mendel was a monk and not a university professor, his work did not receive much attention from other scientists. -Mendel's data was largely ignored for more than 30 years.

A pea plant requires an enzyme to produce flowers that are purple. If this enzyme is not functional, the flowers will be white. Based on this information, which of the statements are true? Multiple select question. -The non-functional allele is most likely recessive to the normal allele. -The allele for the white flower phenotype is most likely recessive to the normal allele. -The allele for the white flower phenotype is most likely dominant to the normal allele. -The normally functional allele is most likely recessive to the non-functional allele.

-The non-functional allele is most likely recessive to the normal allele. -The allele for the white flower phenotype is most likely recessive to the normal allele.

Which of the following genotypes could be represented with the notation A- bb? Multiple select question. AA bb aa bb Aa bb aa BB Aa Bb

AA bb Aa bb

How do geneticists limit the number of variables under investigation at one time?

By studying inbred populations of experimental organisms

What is the name for the diffuse complex of DNA and proteins in a eukaryotic cell?

Chromatin

Select the aspects of meiosis that contribute to genetic diversity in a population. Multiple select question. -Crossing-over -Chromosome condensation -Reduction in chromosome number -Independent assortment

Crossing-over Independent assortment

A true-breeding tall pea plant with yellow seeds is crossed with a true-breeding short pea plant that has green seeds and the offspring are allowed to self-fertilize. What type of cross is this?

Dihybrid cross

What accounts for equal expression of genes on the sex chromosomes despite the fact that males and females have an unequal complement of sex chromosomes?

Dosage compensation

In 1903, Walter Sutton suggested that chromosomes carry Mendel's hereditary units. Select the reasons he gave for this proposal. Multiple select question. -During meiosis, homologous chromosomes and alternative alleles of a gene pair then separate to different gametes. -Both chromosomes and genes contain DNA. -In all cells derived from a fertilized egg, half of the chromosomes and genes have maternal origin, and half have paternal origin. -Both chromosomes and alleles of unrelated genes assort independently. -Every cell has two copies of each chromosome, and there are two copies of each kind of gene.

During meiosis, homologous chromosomes and alternative alleles of a gene pair then separate to different gametes. In all cells derived from a fertilized egg, half of the chromosomes and genes have maternal origin, and half have paternal origin. Both chromosomes and alleles of unrelated genes assort independently. Every cell has two copies of each chromosome, and there are two copies of each kind of gene.

Melanocytes in the skin of dogs can produce either a dark pigment called eumelanin, or the light pigment called pheomelanin. Which pigment will be produced is specified by a transmembrane protein that acts as a switch. This protein is specified by the _____.

E gene

During which part of interphase do cells achieve the majority of their growth?

G1

If a genotype is represented as H- J-, which of the following genotypes could it represent?

Hh Jj Hh JJ HH JJ HH Jj

What term describes how many members of a population who have a particular genotype exhibit the expected phenotype?

Penetrance

A member of the heterogametic sex ____.

can make two different types of gametes

During the G1 part of interphase, ______.

cells grow in size

A mutation is defined as a _____.

change in the genetic material

When a cell evaluates the results of previous steps, this is called a(n)

checkpoint

In 1902-1903, Walter Sutton proposed that ________ contain genes.

chromosomes

The structures within all living cells that contain the genetic material are called

chromosomes

A true-breeding tall pea plant with purple flowers is crossed with a true-breeding short pea plant with white flowers and the offspring are allowed to self-fertilize. This type of cross is a ______ cross.

dihybrid

A trait for which the phenotypes fall into clear-cut categories, such as green peas or yellow peas, is an example of a(n) __________ trait.

discontinuous

The type of genetic interaction in which the effect of an allele of one gene masks the effects of alleles of a second gene is called

epistasis

A discontinuous trait is a trait whose phenotypes _____.

fall into discrete categories

Gametes, or sex cells, are produced by a process called

gametogenesis

The __________ is the basic unit of biological information.

gene

Synapsis is the process by which _____.

homologous chromosomes recognize each other and begin to align themselves in prophase I

Choose the alleles that determine the ABO blood type in humans. Multiple select question. IO i IA IB O

i IA IB

When the alleles of a gene exhibit incomplete dominance or codominance as opposed to complete dominance, the number of resulting phenotypic classes among the F2 offspring of a dihybrid cross will _____.

increase

Meiosis increases genetic diversity in a population through crossing-over and by _________ assortment of parental chromosomes.

independent

Human females produce egg cells by a process called

oogenesis

To determine inheritance patterns in humans, researchers use a chart called a _________ that represents family relationships.

pedigree

The allele for sickle-cell disease leads to multiple changes in the individual's phenotype, including the type of hemoglobin produced, the shape of red blood cells, the onset of anemia and reduced susceptibility to malaria. The name for these multiple effects on phenotype is ______.

pleiotropy

One limitation of selective breeding prior to Mendel's work was the inability to ____.

predict when offspring would inherit a valuable trait

If the chromosomes decondense during the preceding interphase, they recondense during ________ II of meiosis.

prophase

The term penetrance describes the ____.

proportion of individuals with a particular genotype who exhibit the expected phenotype

An inheritance pattern in which all offspring of two affected individuals are affected is most likely to be autosomal ______ inheritance.

recessive

When a preexisting allele is changed to a version that no longer codes for a functional protein, the new allele is likely to be ______ to a normal allele.

recessive

Two genes that specify nearly identical proteins that perform the same function are called ________ genes.

redundant

A cross in which the pollen and egg come from the same plant is called ______.

self-fertilization

A _________ cell is any cell of the body that is not a gamete or precursor to a gamete.

somatic

Y-linked traits would pass from a father to all of his ______ , and none of his _______ .

sons daughters

Male humans produce mature sperm by a process called

spermatogenesis

During prophase of meiosis I, homologous chromosomes recognize and begin to align with each other via a process called

synapsis

The probability of two or more independent events occurring together is calculated by multiplying the probability of each event. This is known as ____.

the product rule

Chromosomes are best defined as ______.

the structures within living cells that contain the genetic material