BIO TEST 4

Match the phenotypes at the top of the figure with the number of Barr bodies you would expect to see in the cells of the individual.

0=Turner syn XYY 1=Norm Fem NOT Norm Male Kline Syn 2= Triple X

Label the following structures associated with plant development.

1. Buds 2. Shoot 3. Root 4. Cotyledoh

Animal development occurs in four overlapping phases, and specific types of transcription factors are important in each phase. Match the correct description of each phase of development with the appropriate picture. Then identify which type of gene/s is/are important in each phase.

1. Est bod ax---Mat ef gene 2. Seg-----Gap gene 3.Cell fate is---- Not seg pol gene 4. NOT cell ty spec---Not pair rule

On a volcanic island, you discover a new species of fruit fly, and while investigating that species, you discover a novel morphogen that you call Morphogen A. When morphogen A is above the threshold concentration of 30 pM, the cells develop into anterior structures. You find some mutant embryos and measure the concentration of Morphogen A along the anteroposterior axis in the mutant oocytes and in normal oocytes of the mutant line. Drag the embryo - either the normal embryo or one of the mutants - to the graph that best represents the Morphogen A concentration in the oocyte. An embryo can be dragged to more than one graph.

1. Normal 2.Mut 1 3. Mut 2 4. Mut 1

An organism possesses an inversion in only one homologue of a chromosomal pair. When this organism's germ cells undergo meiosis, how many of its gametes will also possess the inversion (assume crossing over does NOT occur)?

1/2 of its gametes

Consider a cell that has three pairs of chromosomes. What fraction of the gametes produced from this cell will contain only maternal chromosomes?

1/8

How many bivalents are formed in a cell with 20 chromosomes at the beginning of meiosis I?

10

Consider a cell that has four pairs of chromosomes. How many orientations of all chromosomes are possible during meiosis I in that cell?

16

Which of the following describes meiosis II in humans?

1N -> 1N

If sister chromatids failed to separate during meiosis II, what would the resulting gametes look like?

2 gametes will be normal, 1 gamete will have 2 of the affected chromosomes, and 1 gamete will have 0 of the affected chromosomes.

If a homologous pair of chromosomes fails to separate during meiosis I, what will be the result?

2 gametes will have 2 of the affected chromosomes and 2 gametes will have 0 of the affected chromosomes.

If crossing over occurs between two chromatids on a single pair of homologous chromosomes, how many gametes will have a recombinant chromosome?

2 of the 4

Arrange the following events in the proper order in which they occur during meiosis I. 1 = Separation of homologous chromosomes 2 = Synapsis 3 = Crossing-over 4 = Random assortment of chromosomes on metaphase plate

2, 3, 4, 1

Assume that the F2 generation from the previous question had the following phenotypic ratios: Long stingers and bi-lobed wings (298); short stingers and tri-lobed wings (322); long stingers and tri-lobed wings (97); and short stingers and bi-lobed wings (77). What is the recombination frequency of these two genes?

22%

Consider a cell that has a diploid chromosome number of 10 (2n=10). How many possible genetically distinct gametes can this cell produce?

32

In meiosis I ______. ?

?

Stem cells are categorized according to their developmental stage and their ability to differentiate. Match the following sources of stem cells with their appropriate ability to differentiate.

A. Embryonic Stem (ES) Cells Pluripotent Correct B. Hematopoietic Stem Cells (HSC) Multipotent Correct C. Fertilized Egg Totipotent Correct D. Skin Cells Unipotent

Phenotype is not often determined by one gene (i.e. metabolic rate is determined by the combination of multiple genes). In addition to an organism's genotype, the environment can influence phenotype. A rabbit breeder has established that rabbit body weight is determined by the combination of 3 genes as well as ambient temperature during the first 4 weeks after birth. The three genes involved in the determination of body weight are gene A (fat deposition), gene B (appetite), and gene C (gastric motility). Each gene can occur in heavy and light alleles (indicated by upper case and lower case letters, respectively). If a rabbit is heterozygous for each gene (Aa, Bb, Cc), the rabbit is an intermediate weight. If a rabbit is homozygous for all of the light genes (aa, bb, cc), the rabbit is lightweight. If a rabbit is homozygous for all of the heavy genes (AA, BB, CC), the rabbit is heavyweight. Additionally, rabbits reared at low temperatures during early development will deposit additional fat, making them heavier, whereas rabbits reared at high temperatures will not deposit as much adipose tissue. Arrange the following genotype and ambient temperature combinations from heaviest to lightest weight rabbits.

AABBCC -4---AaBBCc -4------AABbCc 70----- AaBbCc 70----- aabbcc 70

Which of the following represents a characteristic(s) of ALL stem cells?

All stem cells have the capacity to divide. Their daughter cells can differentiate into one or more specialized cell types. When a stem cell divides, one of the daughter cells can remain a stem cell, while the other can differentiate into a specialized cell type. All stem cells from a given organism contain the same genome. All stem cells from a given organism contain the same genome. Correct All stem cells have the capacity to differentiate into specialized cell types. All stem cells have the capacity to differentiate into specialized cell types. Correct Stem cells replenish our skin cells and red blood cells. Stem cells replenish our skin cells and red blood cells. Correct

The following are processes that apply to either plant development or animal development or both. Please classify them accordingly.

Animal= Cell mig Pattern form oc in 4 gen stages Both=Pat form Trans fac reg pat form Hom gen inv in dev

Which statement about mitosis and cytokinesis is TRUE?

At the end of cytokinesis there are two daughter cells with a normal complement of diploid genetic material.

Random orientation of chromosomes during meiosis increases the amount of variation in the next generation. What other process during meiosis leads to an increase in variation in the next generation?

Crossing over between homologous chromosomes.

In Down syndrome, an extra chromosome 21 is present in body cells. In Turner syndrome, there is only a single X chromosome present (and no Y chromosome). In Patau syndrome, there is trisomy for chromosome 13. An abnormality in chromosome number is called a/an aneuploid state. Individuals with Klinefelter syndrome develop as sterile males, although they have an extra X chromosome (XXY). In general, abnormalities involving autosomes are more severe (i.e. include mental impairment) than those involving the sex chromosomes.

During prophase of mitosis, chromosomes are condensing; during prophase II of meiosis, chromosomes are already condensed from meiosis I.

Which of the following is NOT a true difference between mitosis and meiosis?

During prophase of mitosis, chromosomes are condensing; during prophase II of meiosis, chromosomes are already condensed from meiosis I.

In germline cells, when does DNA replicate?

During the S phase

Which of the following are ACCURATE about extranuclear inheritance? Check all that apply.

Extranuclear inheritance is the transmission of genes that occur outside the nucleus. A young girl is diagnosed with neurogenic muscle weakness, a mitochondrial disease. She almost certainly inherited it from her mother. Plants have two extranuclear genomes, animals have one extranuclear genome. Plants have two extranuclear genomes, animals have one extranuclear genome. Correct Mitochondria and chloroplasts have small circular genomes that replicate independently from the nuclear genome.

Consider a normal chromosome with the following gene sequence along its length: F G H I J K L. Which of the following sequences represents an inversion?

F G K J I H L

A cell that is an environment that has an abnormally low pH will NOT pass through which check point?

G1

Using the chart at the beginning of the animation and your knowledge of cells, in what stage of the cell cycle do most cells spend the majority of their lives?

G1

Which of the following represents the correct order of the phases of the cell cycle?

G1 -> S -> G2 -> M

The cell cycle is regulated by checkpoints during the _______ phases.

G1, G2, and M

DNA repair enzymes will be highly active during what phase of the cell cycle.

G2

The success of DNA replication is assessed during the ______ phase.

G2

Which of the following statements best describes the evolutionary outcome of gene duplication events?

Gene duplications allow for higher complexity in organisms, as genes can take on more specialized functions.

Which of the following statements are ACCURATE regarding homeotic genes and homeotic proteins? Check all that apply.

Homeotic genes encode transcription factors Homeotic genes encode transcription factors Correct Homeotic proteins bind regulatory regions of genes important in development Homeotic proteins bind regulatory regions of genes important in development Correct In animals, the order of homeotic genes on a chromosome correlates with their spatial order of expression in the embryo The homeodomain of a homeotic protein has an arrangement of alpha-helices that can bind DNA The homeodomain of a homeotic protein has an arrangement of alpha-helices that can bind DNA Correct Homeotic genes from plants do not contain a homeobox sequence Homeotic genes from plants do not contain a homeobox sequence Correct Homeotic genes found in mammals are homologous to homeotic genes found in Drosophila Homeotic genes found in mammals are homologous to homeotic genes found in Drosophila Correct

Meiosis II separates sister chromatids. What might make sister chromatids differ from each other?

If sister chromatids were recombined during crossing over

Part of a chromosome is duplicated. Why might this be a positive evolutionary force?

If there are two genes, one is free to mutate and take on a different function.

How is the formation of the spindle during mitosis and meiosis I different?

In mitosis spindle fibers from both centrosomes attach to each chromosome's centromere. In meiosis I the spindle fibers from only one centrosome attach to a chromosome's centromere.

Why are two phases of meiosis necessary?

In order to both reduce the chromosome number and separate sister chromatids

Docetaxel is a drug that is used in the treatment of cancer. It interferes with cell division by inhibiting microtubule depolymerization. Specifically, what effect will this have on mitosis?

It will prevent sister chromatids from separating during anaphase.

Evaluate the following examples and determine which is most likely a result of a gene duplication.

MyoD is a protein involved in muscle cell differentiation. Other proteins involved in the same process and possessing similar amino acid sequence are myogenin, Myf5, and MRF4.

J, K, L, M, and N are five genes found on a single chromosome in rabbits. The recombination frequencies between the five genes, as determined by multiple experimental crosses, are shown below. L-J = 31% L- M = 40% M-J = 9% N-K = 8% N-J = 19% K-M = 20% Knowing that Gene L is at position 1 on the rabbit chromosome shown below, place the remaining genes in their appropriate positions.

N----K----J----M

A male mouse that is heterozygous for a mutant Igf2 allele (Igf2/Igf2-) is crossed with a female who is homozygous for the wild-type Igf2 allele. What would be the expected outcome of this cross?

NOT All offspring would be normal because the paternal allele is expressed

The plastid composition of egg cells of four o'clock plants depends on the phenotype of the parent plant. A variegated plant will produce which of the egg cells shown below?

NOT B only

An egg cell from a variegated female four o'clock plant is fertilized with a sperm from a green four o'clock plant. Which of the following is/are possible phenotypes of the progeny of this cross?

NOT white

A gene for coat color in cats is found on the X chromosome. Drag the phenotypes shown on the top to the 8-cell embryo that shows the genotype that will give rise to that phenotype.

OB= Calico OO= Orange NOT albino BB= Black

Why do chromosomes condense during prophase?

So that they will not be damaged when they are moved around the cell

Which of the following statements are ACCURATE regarding genomic imprinting?

Sperm cells silence some genes with molecular imprints and egg cells silence other genes. Genomic imprinting is permanent in the somatic cells of a given individual. Researchers have shown that a human mother's genes influence brain development while a human father's genes influence growth. This indicates that during human brain development, the father's genes are imprinted. Imprinting may involve a single gene, part of a chromosome, or a whole chromosome. Imprinted genes are methylated. The methylation state of a gene may be altered when an individual makes gametes.

The cell cycle consists of several checkpoints at which the cycle can be stopped before continuing to the next phase. Which of the following is not a function of these checkpoints?

Supplying energy for the replication of chromosomes into pairs of sister chromatids

Which of the following statements about plant development is/are ACCURATE?

The basal cell produced by the first zygotic division is larger than the apical cell. By the heart stage of embryonic development, the basic organization of the plant has been established. Cotyledons are embryonic leaves that store nutrients for the developing embryo and seedling. Cotyledons are embryonic leaves that store nutrients for the developing embryo and seedling. Correct Meristems are present in a heart stage embryo. Meristems are present in a heart stage embryo. Correct The root apical meristem gives rise to the root.

In cats, a gene for coat color is found on the X chromosome. The picture below shows a mass of cells making up an early female cat embryo that is heterozygous for coat color (B = Black; O = Orange). Which of the following statements is ACCURATE about this embryo?

The initial inactivation pattern is maintained in all descendants of each cell as the embryo matures into an adult. The cat will have a calico pattern as an adult. At this point in development, both alleles are active In each embryonic cell, one X will be randomly inactivated. The adult cat will be mosaic for coat color.

You find a Drosophila embryo in which segments A1, A2, A3, and A4 are missing. Which of the following is accurate about the molecular defect in this mutant?

There is a mutation in a gap gene. There is a mutation in a gene encoding a transcription factor.

Which of the following statements about microtubules during anaphase is TRUE?

Those attached to chromosomes shorten, while those that are unattached elongate.

In a translocation, the absolute amount and content of the genome remains the same. Why might some translocations still make an organism inviable?

Translocations may have break points in the middle of a gene, causing it to become nonfunctional.

Chromosome duplication occurs prior to both mitosis and meiosis.

True

Outcome of misaligned crossover

a deletion in one chromosome and a duplication in the other.

Mitosis results in the formation of two genetically identical daughter cells. This is because

all the genetic material is duplicated then segregated equally to the daughter cells.

Which of the following is unique to meiosis?

crossing-over

Sister chromatids separate in

mitosis and meiosis II.

Homologous genes within the same species

paralogs

An inversion is best described as a

reversal in the orientation of a segment of a chromosome.

A 2n=6 germline cell completes meiosis I. Each daughter cell ?

?

Why must chromosomes form a loop in order to pair during meiosis if one of the homologues has an inversion? ?

?

Which type of chromosomal mutation will usually have the MOST detrimental effect on organismal function and why?

A deletion, because there will be no protein product produced for genes in the affected region.

Because the genes are linked, the expected ratio in the F2 generation would be 50% with gray bodies and straight wings and 50% with black bodies and curved wings. But four different phenotype combinations appear in the offspring, the two expected phenotypes as well as offspring with gray bodies and curved wings and offspring with black bodies and straight wings. Which of the following best explains what happened?

A recombination occurred during the formation of the F1 female's egg cells.

What can be inferred from the color of the offspring in each cross?

Pigment is maternally inherited

Classify the following tissues as either a "plausible" or "implausible" source of stem cells.

Plausible- Bone Marrow Spontaneously Fertilized Human Adult mouse

A chromosome has undergone a translocation that has completely deleted its centromere region, preventing association with spindle fibers. Other than this loss of sequence, the remaining DNA of this chromosome is undamaged. What will be the fate of this cell?

The cell will not pass the M checkpoint because its chromosomes will not all associate with spindle fibers.

The stinging nettle is a flowering plant common to North America, Europe, Asia, and northern Africa and has a history of use as medicine for humans. The leaves and stems are very hairy with both stinging and non-stinging hairs. When contacted by humans and other animals, the tips of the stinging hairs break off, and the hair is transformed into a needle that injects chemicals that cause a stinging/burning sensation. Imagine in nettles that there is a gene encoding plant height (T = tall; t = short) and a gene encoding the number of stinging hairs present on the plant (H = many stinging hairs; h = few stinging hairs). A true-breeding tall nettle with many stinging hairs is crossed to a short nettle with few stinging hairs. The resulting F1 is crossed to a short nettle with few stinging hairs. The following offspring are generated: 177 tall, many stinging hairs 198 short, few stinging hairs 10 tall, few stinging hairs 15 short, many stinging hairs What do these data tell you? Select all that apply.

The genes for plant height and number of stinging hairs assort independently. NOT The genes for plant height and number of stinging hairs are on different chromosomes. IS The genes for plant height and number of stinging hairs are on the same chromosome. The genes for plant height and number of stinging hairs are linked. There is occasional crossing over between the genes for plant height and the gene for number of stinging hairs.

On a volcanic island, you discover a new species of fruit fly, and while investigating that species, you discover a novel morphogen that you call Morphogen A. When morphogen A is above the threshold concentration of 30 pM, the cells develop into anterior structures. You find a fruit fly oocyte with normal morphogen concentrations along its anteroposterior axis (a concentration gradient seen in wild type oocytes), but the resulting embryo does not properly develop a head, mouth, eyes, and other anterior structures. Which of the following is a reasonable explanation for the appearance of the headless mutant?

The headless mutant has a defect in a gene encoding a cell adhesion molecule.

A plant has a reciprocal translocation between two chromosomes. It is heterozygous for this translocation, i.e. one set of chromosomes is normal, without the translocation. What effect can you be sure that this translocation has on the health and fertility of the plant?

The plant will make some normal gametes (with the full complement of DNA) and some abnormal gametes (without the full complement of DNA).

How can you compare the complement of DNA in an interphase (G1) diploid cell and a cell that has just completed meiosis I?

They have the same amount of DNA, but the meiotic cell has half as many chromosomes.

Polyploidy in wheat is common. The tetraploid species (2n=4x=28) Triticum dicoccoides and Triticum araraticum are the wild ancestors of most domestic tetraploid varieties. There are no wild hexaploid species. Triticum aestivum is the common, hexaploid (2n=6x=42) wheat that is used to make bread and other baked goods. It is the result of a cross between a domestic tetraploid wheat (such as Triticum durum, the wheat used to make pasta) and a wild diploid goat grass Aegilops tauschii. Which of the following statements about wheat is TRUE?

Wheat species that are hexaploid have a higher level of diversity within their genomes than do wheat species that are tetraploid of diploid

Which of the following events occur during prophase I?

breakdown of nuclear envelope, condensation of chromosomes, and movement of centrosomes

In meiosis, a chromosome carrying an inversion

can pair with a normal homologous chromosome by forming an internal loop.

Which of the following events do NOT occur in prophase of mitosis?

chromosomes are replicated

The division of the cytoplasm is called

cytokinesis.

A cell is considered to be ______ when it is committed to becoming a particular cell type, such as an intestinal cell or a muscle cell. A cell is considered to be ______ when its morphology and function have changed, usually permanently, into a highly specialized cell type.

determined/differentiated

Which of the following causes an extra copy of a chromosomal region to occur?

duplication

At the end of meiosis II, there are

four haploid cells, with each chromosome consisting of a single chromatid.

Daughter cells produced in meiosis have

half the number of chromosomes as daughter cells produced in mitosis.

Origin of homologous genes

have a common ancestral gene.

The four daughter cells produced in meiosis

have one of each pair of chromosomes found in the parent cell.

The function of sexual reproduction is to increase variation within populations. Meiosis is the molecular mechanism that leads to sexual reproduction. As such, some of the features that make it unique lead to genetic diversity. Which of these unique features are responsible for increasing genetic diversity?

homologous recombination and reduction division

When a chromosome is broken in two places and reconnected so that a region is flipped from the normal order, this is called...

inversion

The mitotic spindle fibers attach to chromosomes via special structures termed

kinetochores.

Random orientation of homologous chromosomes occurs in ________ of meiosis.

metaphase I

A eukaryotic cell that receives a "go-ahead" signal at the G1 checkpoint of the cell cycle will

move into the S phase and continue the cell cycle.

A crossover in meiosis is an exchange of genetic material between

non-sister chromatids of homologous chromosomes.

The spindle apparatus is fully formed by the end of

prometaphase II.

Which of the following represents the correct order of the phases of mitosis?

prophase -> metaphase -> anaphase -> telophase

Which of the following events occur during anaphase I?

separation of homologous chromosomes

Which of the following occurs when a piece of one chromosome breaks off and is attached to another chromosome?

simple translocation

Separation of ________ occurs in anaphase II of meiosis.

sister chromatids

Crossing over is possible due to what event that occurs in meiosis I but not mitosis?

synapsis

Which of the following features are unique to meiosis?

synapsis, homologous recombination, and reduction division

During the G2 phase, the cell is preparing for mitosis. Using your knowledge of cellular organelles and molecules, which molecule is produced in the highest quantity during the G2 phase?

tubulin, the microtubule protein

The number of cells produced in meiosis is

twice the number of cells produced in mitosis.