the majority of down syndrome cases are a result of maternal gamete carrying an abnormal number of chromosomes

Question 1

What post-translational modification will cause the biggest increase in the size of a protein, immediately when added?

Select one:

a. Phosphorylation

b. Ubiquitination

c. Acetylation

d. Methylation

Question 2

What does HMT do?

Select one:

a. It acts as an epigenator

b. It modifies nitrogenous bases

c. It produces euchromatin

d. It modifies histones

Question 3

Where can an epigenetic maintainer act?

Select one:

a. On the sequence of nucleotides

b. On the sequence of nucleotides and on the nucleotides directly

c. On certain nucleotides and amino acids

d. On certain amino acids

e. On certain nucleotides

Question 4

Which of the following types of protein could be coded by a tumour-suppressor gene?

Select one:

a. A protein that stimulate progression through the cell cycle.

b. A protein that forms part of a growth factor signaling pathway.

c. A protein that codes for a DNA repair enzyme.

d. A protein that helps prevent apoptosis.

e. A protein that repairs lost telomeres

Question 5

Which is NOT a typical mechanism by which a proto-oncogene is converted to an oncogene?

Select one:

a. A point mutation in the proto-oncogene

b. A chromosomal translocation resulting in the up-regulation of the proto-oncogene

c. Duplication of a chromosome region containing a proto-oncogene

d. Complete deletion of the proto-oncogene

e. Amplification of the proto-oncogene

Question 6

Why do you think familial retinoblastoma and Li-Fraumeni are considered to be inherited as autosomal dominant traits when the responsible genes are recessive?

Select one:

a. They are expressed in a dominant fashion in males, but recessive in females.       

b. People with this mutation are always homozygous for this allele.

c. If you are born with one allele mutated in every cell, the chance that the other allele will be mutated in one of the retinal cells is extremely high.

d. This recessive gene needs only one copy to express this phenotype.

e. Retinoblastoma was mischaracterized originally when it was called an autosomal dominant trait.

Question 7

Question text

In a normal cell, pRB binds to __________, which inhibits cell division. In the presence of __________ pRB becomes __________, which leads to cell division.

Select one:

a. cyclin+Cdk; oncogenes; dephosphorylated

b. transcription factors; cyclin+Cdk; phosphorylated

c. tumor suppressor; p53; phosphorylated

d. p21; p53; dephosphorylated

e. tumor suppressor; p21; hyperactive

Question 8

The following information relates to the next three questions:

A few decades ago, Knudsen and colleagues proposed a theory that, for a normal cell to become a cancer cell, a minimum of two genetic changes had to occur in that cell. Knudsen was studying retinoblastoma, a childhood cancer of the eye.

Two children are born from the same parents. Child one inherits a predisposition to retinoblastoma (one of the mutations) and child two does not. However, both children develop the retinoblastoma. Which of the following would you expect?

Select one:

a. a history of exposure to mutagens in child one but not in child two

b. increased levels of apoptosis in both children

c. an earlier age of onset in child one

d. decreased levels of DNA repair in child one

e. a more severe cancer in child one

Question 9

In colorectal cancer, several genes must be mutated in order to make a cell a cancer cell, supporting Knudsen’s hypothesis. Which of the following kinds of genes would you expect to be mutated?

Select one:

a. genes that are especially susceptible to mutation

b. the same genes that Knudsen identified as associated with retinoblastoma

c. genes coding for enzymes that act in the colon

d. the genes of the bacteria that are abundant in the colon

e. genes encoding transcription factors that regulate cyclin production

Question 10

Knudsen and colleagues also noted that persons with hereditary retinoblastoma that had been treated successfully lived on but then had a higher frequency of developing osteosarcomas (bone cancers) later in life. This provided further evidence of their theory because:

Select one:

a. osteosarcoma cells express the same genes as retinal cells.

b. one of the mutations involved in retinoblastoma is also one of the changes involved in osteosarcoma.

c. p53 gene mutations are common to both tumours.

d. retinoblastoma is a prerequisite for the formation of osteosarcoma later in life.

e. both kinds of cancer involve uncontrolled proliferation of cells.

1. the number of new virions released from each bacterium host cell represent the _______.

2. "phage" attacks and multiple in __________.

3. Freezing and drying for long term storage is known as ________. (hint! coffee is preserved that way as well).

4. the organelle _______ found in certain fungi, plugs the pores of hyphal cells to prevent materials from adjacent damaged cells to move to the healthy cell.

5. those hyphae responsible for anchoring the fungus into the substratum are known as ________.

6. the stage (in viral replication cycle) which assembly of newly synthesized viral components into complete virions is called ________.

We are moving towards "eugenics." What is "eugenics" and what should we consider a defect and so a trait to be eliminated?

What would be a portion size per serving for this menu for a preschooler (3 year-old toddler): rice, pinto beans, chopped tomatoes, yoghurt.

What do the R_f values indicate about the relative solubilites of the pigments in the water and solvent phases?

Explain the relative solublities of chl b and chl a in the water and solvent phases on the basis of molecular structure.

Explain the relative solublities of b-carotene, lutein, and violaxanthin in the water and solvent phases on the basis of molecular structure.

Explain in detail the mechanism of breathing.Discuss briefly about respiration and acid base balance. Discuss briefly about the structural layers of alimentary tube.

What ecology theories are present in Aldo Leopold's A Sand County Almanac in chapters 1-6?

Each year in late January comes a thaw. The hibernating skunk rouses and walks through the snow, leaving a track behind him. Aldo Leopold, author and speaker, follows the track, wondering about the skunk's purpose and destination. There is time for such musings in January.

Following the skunk track Leopold notices more signs of animal activity as a result of the thaw. A mouse runs across the skunk track. The thaw has exposed its network of tunnels beneath the snow. A hawk dives from the sky for prey, "well aware that snow melts in order that hawks may again catch mice." Rabbits run more freely, giving owls opportunities to feed.

The skunk track ends at a pile of driftwood, so Leopold goes home again.

According to Leopold, among the benefits of owning a farm is a greater understanding of where food and heat come from. Using the example of a felled oak used as fuel for the fire, he examines the origin of the energy in the wood and the process that led to its being used to provide warmth.

This particular oak had reached a diameter of 30 inches, made up of 80 rings. This dates the first ring to the end of the Civil War. The heat generated by burning the wood is, then, "eighty years of June sun." And this heat is greatly appreciated by Leopold's dog.

The oak had been struck and killed by lightning in a summer storm. Leopold felled it, imagining that the "saw was biting its way, stroke by stroke, decade by decade, into the chronology of a lifetime, written in concentric annual rings of good oak." He thinks of the oak over the years as he saws, imagining backward in time through the Great Depression, years of changes to conservation laws, and other significant dates in Wisconsin's conservation and forestry history. He also describes the function of the saw, wedge, and axe—tools for cutting up wood—not only as they relate just to cutting the tree but also how they interact with and reveal the years represented by the rings.

The return of geese in March means spring has truly and fully come. Other animals—cardinals and chipmunks—do not migrate, so they can be mistaken about the coming of spring. But geese migrate, so there is no room for error in timing. The return of hundreds of geese to the marsh on Leopold's property is a sure sign that the season is changing. The geese show their presence and eat last year's corn from fields that have been hidden under snow all winter.

Leopold notes some of the geese are "singles—lone geese that do much flying about and much talking." After careful observation he concludes these are "bereaved survivors of the winter's shooting, searching in vain for their kin." Leopold describes the noise of the birds in the marsh as a robust and boisterous conversation that, by May when the geese have migrated on, becomes much quieter. Through the migration of the geese, Leopold notes, the leftover corn from Illinois is transformed under the Arctic June sun into goslings.

Come High Water

Because of melting snow and the farm's proximity to the river, April often brings flooding to Leopold's farm. This causes both humans and animals to be stranded on high areas surrounded by fields rapidly being transformed into lakes. The geese struggle to find a place to land and feed, while the carp enjoy their larger world. Random pieces of lumber float down the river from areas upriver. Over the years these have been collected in a lumber pile that is "an anthology of human strivings in upriver farms and forests."

Draba

The tiny white blossoms of the Draba flower can go unnoticed by those who are not looking for them. It is a humble and overlooked flower that thrives in sand that is too poor for other flowers. Draba is not a romantic flower, but it does its "small job quickly and well."

Bur Oak

Because of its thick bark the bur oak is the only Wisconsin tree that can survive a prairie fire: "Bur oaks were the shock troops sent by the invading forest to storm the prairie; fire is what they had to fight." Botanists can use pollen embedded in the wood of trees to track the expansion and contraction of the Wisconsin forest over the course of this long battle between forest and prairie. Because of "allies"—rabbits, mice, squirrels, June beetles—that helped both the prairie and the forest, "the net outcome of the battle was a draw." That is, until human settlers intervened in the battle. Settlers plowed fields so that prairie fires were less common. This gave oaks an advantage as more of their seedlings could survive. This allowed much of the land that was prairie to be transformed into thick oak forest.

Sky Dance

In April and May the "sky dance" occurs at dusk and dawn over the woods of the Leopold farm. "Showtime" changes over the weeks as the times of sunrise and sunset change. At the appointed time the male woodcock bird appears and begins to perform a song and dance designed to appeal to his "lady." He spirals into the sky and swoops down for an hour or more, his "dance" accompanied by his unique call. Despite Leopold's careful observation of this sky dance he has many unanswered questions about it, such as where the female is during this dance and the exact mechanism of the music.

When dandelions begin to bloom in Wisconsin, one can listen for the "final proof of spring"—the song of the upland plover, which migrates far to the Argentine during the winter. The plover can be seen flying overhead or alighting gracefully on fence posts. Over the next several weeks the hens nest; the chicks hatch out and grow quickly; by August the chicks have learned to fly.

The plover has adapted well to the changes human agriculture has wrought on the landscape—it lives as easily among cows and farmland as among buffalo and prairie. They have also benefitted from federal migratory bird laws that protect them from hunters.

The Alder Fork—A Fishing Idyl

In this episode Leopold fishes for trout in a stream but has little luck. He relocates his fishing efforts to the Alder Fork—a part of the stream nearer the headwaters. While catching trout, Leopold sits on a rock and considers how much humans are like fish: "ready, nay eager, to seize upon whatever new thing some wind of circumstance shakes down upon the river of time!" He notes that this haste may sometimes have bad effects, but a life devoid of this eagerness would be very dull. Prudence may often be a virtue, but a life wholly prudent is boring. In fact, he remarks: "No prudent man is a fisherman."

1. Sex determination in Mammals. You have identified a gene that you have named “mont1” (for ‘make ovaries not testes’) that is expressed at the time when the bipotential gonad becomes specified to become an ovary. Because of this “show it” evidence that mont1 is expressed in the right place at the right time, you hypothesize that mont1 is a critical regulator of the female primary sex determination pathway to specify ovary development.
   1. From what you know about the primary sex determination pathway for ovary development, what signaling pathway would you predict may activate mont1 expression?
   2. What “lose it” experiment could you do to determine if mont1 is necessary for ovary development. Briefly describe the expected result. (As in … I would do X experiment and expect to see Y result if mont1 is necessary for ovary development).
   3. What “move it” experiment could you do to determine if mont1 is sufficient for ovary development. Briefly describe the expected result. (As in … I would do X experiment and expect to see Y result if mont1 is sufficient for ovary development).

2. Various enteric bacteria, especially E. coli, are the cause of most urinary tract infections in humans. A quick test for the presence of these bacteria in urine is to detect nitrite in the urine. Why?

Whales communicate with one another using sound. What are the benefits of using sound to communicate underwater? What are the costs?

You want to use Cre/loxP system for targeted gene expression instead of knock-out. Briefly describe how this can be accomplished. (3-4 sentences)

1.

A diploid yeast cell (2n = 32) undergoes meiosis. What will be the resulting products?

Group of answer choices

Two diploid cells with 32 chromosomes each

Four diploid cells with 32 chromosomes each

Two haploid cells with 16 chromosomes each

Four haploid cells with 16 chromosomes each

2.

In humans, sex determination involves what mechanism?

Group of answer choices

An X-chromosome mechanism

A Y-chromosome mechanism

An autosomal genic mechanism

It is currently unknown the mechanism that determine biological sex in human