exam 3

During a typical cell cycle, the interphase is composed of which of the following phases

G1, S, and G2 only

The purines found in RNA are

Adenine and Guanine

Where can telomeres be found?

On the ends of eukaryotic chromosomes.

In meiosis, sister chromatids move toward the opposite poles of a dividing cell during

Anaphase 2

Without telomerase

Chromosomes would shorten at the 3' ends at every DNA replication

How many checkpoints does a typical cell cycle have?

3

Growth factors are typically

Paracrine signals

In diploid flying unicorns, having a long horn (H) is a trait that is dominant over short horn (h), and white fur (F) is a dominant trait over pink fur (f). A short horned pink female unicorn mates with a long-horned white male whose parents are a long-horned white father, and a short-horned pink mother. How many different types of gametes can the female produce?

1

In diploid flying unicorns, having a long horn (H) is a trait that is dominant over short horn (h), and white fur (F) is a dominant trait over pink fur (f). A short horned pink female unicorn mates with a long-horned white male whose parents are a long-horned white father, and a short-horned pink mother. If you wanted to draw a Punnett Square to determine the possible outcomes of such a cross, how many rows and columns would your Punnett square have. Please answer this question by entering the number of rows first, followed by a space, and then the number of columns (example: 3 rows and 4 columns would be indicated as 3 4)

1 4

A test tube similar to the one represented above was used for Meselson & Stahl's experiments. When bacteria were grown on nitrogen 15 only, they observed 1 band of DNA in position 5 of this tube. When bacteria were grown on nitrogen 14 only, they observed 1 band of DNA in position 1 of this tube. In Meselson and Stahl's experiment, what type of banding pattern would the scientists have observed after 1 round of replication on nitrogen 14 if DNA replication were a conservative mechanism? In your answer, indicate the number where (a) band(s) would be observed. If more than one band were observed, indicate the various numbers with a space between them. Please, write the lowest number first. (Example 1 band at the top of the tube and 1 band in the middle would be indicated as "1 3", whereas a single band at the top would be indicated as "1")

1, 5

At the end of the G2 phase, a diploid cell with an n=4 has a total of _____ sister chromatids

16

In diploid flying unicorns, having a long horn (H) is a trait that is dominant over short horn (h), and white fur (F) is a dominant trait over pink fur (f). A short horned pink female unicorn mates with a long-horned white male whose parents are a long-horned white father, and a short-horned pink mother. How many different gametes can this male produce?

4

The membrane that forms at the end of telophase to separate daughter cells at the end of mitosis in plants is known as

A cell plate

The genetic regulation of the various blood types observed in humans is a great example of

Codominance

Which of the following proteins is not part of the replisome?

Cyclin dependent kinases

The main replication enzyme involved in prokaryotic DNA copying is called

DNA Polymerase 3

What is the difference between the enzymes DNA polymerase I and ligase?

DNA polymerase I binds to Okazaki fragments, removes the primers, and replaces them with DNA nucleotides. Ligase attaches the Okazaki fragments to make one single continuous strand.

Bacterial cells divide by mitosis

False

Based on the difference is organism complexity, you would expect a chimpanzee to have more chromosomes than a prawn (shrimp)

False

Centrioles are only found in a cell during the M phase of the cell cycle

False

DNA nucleotides have a hydroxyl group at the 2' position on the ribose

False

DNA polymerases can only work on the lagging strand of the replication fork once they are finished with the leading strand

False

The p53 gene is known as a proto-oncogene

False

In diploid flying unicorns, having a long horn (H) is a trait that is dominant over short horn (h), and white fur (F) is a dominant trait over pink fur (f). A short horned pink female unicorn mates with a long-horned white male whose parents are a long-horned white father, and a short-horned pink mother. What is the male's genotype?

HhFf

In a cancerous cell, you would expect telomerase activity to be

Higher than in a healthy cell

The proteins that hold homologous chromosomes after replication are called

Homologous chromosomes are NOT held together after replication!

You are transported to an alternate universe where DNA may or may not replicate differently. As an avid biologist, naturally your first quest in this new universe is to replicate Meselson and Stahl's experiment. After two generations of replication, you see one band of DNA in your centrifuged test tube (represented above) in position 2. How does DNA replicate in this alternate universe?

In a dispersive manner

DNA polymerases read the DNA

In the 3' to 5' direction

In his experiments, Mendel sometimes crossed tall pea plants with short ones. The outcome of such crosses would always express the dominant allele (either tall or short). If the outcome of such a cross had consistently been a medium size (independently of the conditions in which the plants were grown), the pattern of inheritance for these plants would most likely be called

Incomplete dominance

Which of the following is true about a triploid organism with a n=3 during the G1 phase of the cell cycle

It would have 9 linear chromosomes

Cystic fibrosis is a disease in which people have a mutation in an ion channel called CFTR. This type of channel is found in multiple tissues throughout the body, and a simple mutation in this channel may be expressed in a multitude of ways (sweating disorder, digestive system malfunction, respiratory difficulties, etc...). This type of situation when a genetic mutation expresses itself in a multitude of phenotypes is called

Pleiotropy

Which of the following is NOT a reason for mitotic cell division?

Pollen production in flowers

We established that many growth factors activate the cell cycle by binding to receptor tyrosine kinases (RTK). Sometimes, these RTKs get mutated, and permanently turned "ON." As a result, the cell cycle is stimulated even in the absence of growth factors. In light of this information, you would label the genes that encode for these RTKs as

Proto-oncogenes

Growth factors affect the cell cycle by binding to

Receptor tyrosine kinases (RTK)

Typically, the longest phase of the cell cycle is

The G1 Phase

During mitosis, the protein complex that anchors the replicated chromosomes to the spindle apparatus is called

The kinetochore

A testcross aimed at determining the genotype of an unknown organism with dominant phenotype results in a 1:1 ratio of dominant and recessive phenotypes. Based on this ratio, what can you deduce about the genotype of the unknown organism?

The unknown organism is heterozygous

A human karyotype is composed of 22 pairs of autosomal chromosomes and 1 pair of sex chromosomes

True

A nucleosome is composed of 9 histones (1H1, 2H2A, 2H2B, 2H3, and 2H4)

True

A pair of mutated receptor tyrosine kinase that stay constantly phosphorylated could lead to uncontrolled mitosis, and ultimately formation of a tumor

True

A retinoblastoma (Rb) protein that loses its ability to bind to the E2F transcription factor would lead to an increase in cell proliferation.

True

Caspases are apoptosis-inducing proteins activated by tumor suppressor proteins such as p53

True

Cyclin-dependent kinases (CDKs) can be activated or deactivated via phosphorylation and dephosphorylation

True

During prophase of mitosis, each replicated chromosome attaches to a different microtubule on the mitotic spindle apparatus

True

During the S-phase of the cell cycle, each chromosome has multiple replication bubbles

True

Telomerase contains a template of RNA nucleotides

True

The primers that are attached by DNA primase during DNA replication and made of RNA nucleotides

True

Transcription factors tend to bind to DNA at the level of the major grooves

True

Which of the following is true about tumors

a. Malignant tumors can release cancerous cells in the bloodstream. These cells are called metastases. b. Tumors release angiogenic signals that attract blood vessels c. Tumors can sometimes be fought via immunotherapy

DNA replication is a

semiconservative process