question

Which of the following is not a nucleotide found in DNA?

answer

uracil (U)

question

If the sequence of one strand of DNA is AGTCTAGC, what is the sequence of the complementary strand?

answer

TCAGATCG

question

In addition to the base, what are the other components of a nucleotide?

answer

phosphate and sugar

question

What does each chromosome contain?

answer

DNA and proteins

question

The _______ chromosomes in a human cell from inside the cheek are found in the _______.

answer

46, nucleus

question

You can detect DNA that is specifically from the X chromosome in a DNA sample from a person. Why can't you definitively determine the gender of that person (male or female) from the presence of the X chromosome?

answer

Both males and females have an X chromosome so you would have to check for the presence of a Y chromosome.

question

Human red blood cells are enucleated (that is, they do not have nuclei). Is it possible to isolate DNA from red blood cells? Why or why not?

answer

No, the genomic DNA is found only in nucleated cells.

question

DNA replication is said to be semiconservative because a newly replicated, double-stranded DNA molecules consists of _______________.

answer

one old strand and one new strand

question

Which of the following statements about PCR is TRUE?

answer

DNA polymerase is the enzyme that copies DNA in PCR.

question

What naturally occurring process does PCR mimic in a test tube?

answer

DNA replication

question

If you start with one copy of a DNA fragment, how many rounds of PCR will it take to end up with a total of 32 copies?

answer

5

question

Complete the following statements regarding the steps necessary to copy a DNA sequence during PCR: 1) The two original strands of the DNA molecule can be separated by __________. 2) The enzyme ______________ "reads" each template strand and adds _______________ to make a new strand.

answer

. 1) heat, 2) polymerase; complementary nucleotides

question

What is the purpose of careful primer design before PCR?

answer

Primers dictate the specificity of the place you are amplifying and Primers must "sit" on the original DNA strand to give polymerase a place to start replication.

question

An individual's STR may vary from the same STR of another individual by _____________.

answer

The number of times a particular sequence is repeated

question

What represents genetic variation between individuals?

answer

the presence of STR's in their genomes

question

Gel electrophoresis separates DNA for profiling based on what?

answer

size (length)

question

The entire sequence of DNA in a cell used for DNA profiling is called the ______

answer

genome

question

Which STR will have migrated farthest through an electrophoresis gel?

answer

GAAG repeated twice

question

You are studying the DNA profile of an individual, and you are looking at the results for a chromosome with just one STR site. How many bands will you see?

answer

either one or two

question

Which of the following people would have DNA that is least similar to yours?

answer

your mother's brother

question

DNA evidence can give an investigator information regarding which of the following?

answer

family relationships between suspects, identity of an individual based on a profile, and locations of an individual

question

How many STRs are typically used to create a profile in forensic investigations?

answer

15

question

You are investigating a crime. The DNA profile database has no perfect matches to the DNA collected at the crime scene. However, one profile in the database has at least one band in common with the crime scene DNA at every STR site. Which of the following is the most likely conclusion can you draw?

answer

A parent-child relationship exists between the DNA collected at the crime scene and the DNA in the database.

question

From the STRs used in a forensic investigation, which STRs on which chromosomes would be particularly useful in determining whether crime scene evidence was left by a female or a male?

answer

Y chromosome STR

question

Following mitosis and cytokinesis, daughter cells are _____

answer

genetically identical to each other and genetically identical to the parent cell

question

In the cell cycle, DNA is replicated during ____

answer

S

question

Which of the following processes require normal cell division?

answer

embryonic development, wound healing, replacement of blood cells, and intestinal tract and skin cell replacement

question

During which stage of the cell cycle do sister chromatids separate from each other?

answer

anaphase

question

During which stage of the cell cycle are sister chromatids initially produced?

answer

interphase

question

During which stage of the cell cycle are sister chromatids first visualized?

answer

prophase

question

Which of the following series has the stages of the cell cycle in the proper order?

answer

G1, S, G2, mitosis, cytokinesis

question

In which stage of the cell cycle does the cell spend the most time?

answer

interphase

question

Which of the following series has the stages of mitosis in the proper order?

answer

prophase, metaphase, anaphase, telophase

question

What would be the result if a cell completed interphase and mitosis but failed to complete cytokinesis?

answer

You would only have one cell and You would have twice as many chromosomes as the parent cell.

question

A normal cell that sustains irreparable DNA damage will most likely _____

answer

die by apoptosis

question

Which checkpoint prevents a normal cell from completing its cell cycle if it has not accurately replicated its DNA?

answer

Interphase (G2-M)

question

What is the best definition of cancer?

answer

a disease in which unregulated cell division occurs

question

Cell cycle checkpoints are present to ________

answer

ensure that cancer does not occur and makes sure that each step of the cell cycle occurs accurately

question

When your skin cells are exposed to UV light, such as in a tanning bed, DNA damage can occur. If one of these severely UV-irradiated skin cells is given a signal to divide, what are plausible outcomes?

answer

The cell will go through apoptosis, after the damage is detected.

question

Why would the cell make apoptosis the default mechanism when a problem in the cell cycle is detected?

answer

Apoptosis ensures that the cell dies instead of leading to cancer.

question

Which of the following properties should a promising new ovarian cancer drug have?

answer

blocks mitosis in cancerous cells

question

What are some side effects of cancer chemotherapy drugs?

answer

nausea, diarrhea, hair loss, and bone marrow cell loss

question

Which of the following specific therapies for cancer have the correct corresponding reasons for choosing them?

answer

specific chemotherapies: cancer may be resistant to some chemotherapeutic agents, chemotherapy: metastatic cancer may be too far spread to be treated by surgery and radiaton therapy, nad surgery: tumor mass is in one place and the surgery will not unduly harm the patient

question

A patient has metastatic melanoma—skin cancer. Is surgery a viable option for this patient?

answer

No because the cancerous cells have spread throughout the body

question

Which types of cells are triggered to go through apoptosis by radiation and chemotherapy treatments?

answer

any cell that is rapidly undergoing cell division

question

In the development of chemotherapeutic agents for cancer, what factors must be considered?

answer

environmental costs if the agent is from a living specimen, production costs if the agent is rare or hard to isolate, side effects the drug may have on noncancerous cells

question

If a medically valuable drug is isolated from a rare plant, which of the following steps can be taken to ensure that the drug is made available to patients in need and that the plant is protected from overuse?

answer

1. Try to cultivate the plant on a farm to ensure that sufficient supply is available independent of the plant in its native setting 2. Try to find a related (and less rare) plant that produces a related compound with similar pharmaceutical activity. 3, Use the structure of the compound to try to make a completely synthetic version of the chemical compound in a lab. 4. Learn more about what the drug is doing in the body, and try to design synthetic molecules that might have the same activity.

question

Which of the following will be important for the continued development of chemotherapeutic agents to better fight cancer?

answer

1. identification of compounds from new species of plants and animals from varied environments 2. development of synthetic compounds that mimic naturally occurring compounds with anticancer effects 3.efficient and effective delivery of chemotherapeutic agents to individuals with cancer 4.screening systems to look for potential compounds with anticancer properties

question

In an otherwise normal cell, what happens if one mistake is made during DNA replication?

answer

A cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected.

question

Why does wearing sunscreen reduce cancer risk?

answer

Sunscreen can reduce the chance of mutations caused by exposure to UV radiation present in sunlight.

question

A mutation can cause a change __________

answer

in the amino acid sequence of a protein, the shape of a protein, the way the cell cycle is regulated, and a change that is beneficial to the cell

question

At which of the following points does a mutation exert its potentially dysfunctional effects in a cell?

answer

after a protein is produced

question

DNA mutations can arise from uncorrected errors in DNA replication, inheritance, and __________.

answer

environmental insults

question

If an individual has a germline mutation, which of the following are possible sources of that mutation?

answer

a maternal allele and a paternal allele

question

How does a somatic mutation in a gene alter the function of a cell?

answer

Base pair mutations in a gene are passed directly into mRNA via transcription.

question

A potential cancer-causing gene coding for a protein with cell cycle control responsibilities is a ___________, and a gene coding for a protein that stimulates cell division is a ___________.

answer

tumor suppressor; proto-oncogene

question

What is the role of BRCA1 in normal cells?

answer

BRCA1 acts as a tumor suppressor.

question

Which of the following does not cause cancer to develop and progress?

answer

a proto-oncogene and a tumor suppressor gene

question

A chemical that causes alterations in DNA is a ______________, and if this chemical causes cancer it is called a _______

answer

mutagen; carcinogen

question

Tumors that will not spread throughout the body are _________________, and those that do spread are termed ______________.

answer

benign, malignant

question

What accurately describes cancer development?

answer

It is a multi-step process by which multiple mutations cause a series of events that lead to cancer.

question

What would you say to a niece if she asked you how she could reduce her risk of breast cancer? (Assume there is no family history of breast cancer.)

answer

utilize early screening, avoid tobacco use, reduce your consumption of alcohol, and reduce sun exposure

question

Why is age a risk factor for cancer?

answer

Age extends the amount of exposures to environmental factors, which can lead to the progression of cancer.

question

We would all have many more mutations in our genes if not for the __________

answer

activity of proofreading enzymes

question

Which is the correct order of events in which breast cancer might develop?

answer

inheritance of a mutant BRCA gene > replication errors create an oncogene > mutation of p53 > additional mutations permit spreading

question

A woman with a BRCA1 mutation ____

answer

is at increased risk of developing breast cancer

question

Which of the following family histories most strongly suggests a risk of inherited breast cancer due to BRCA1 mutations?

answer

many female relatives diagnosed with breast cancer at an early age

question

Why do people with "inherited cancer" often develop cancer at a relatively young age?

answer

Predisposition increases the chances that other risk factors will lead to the progression of cancer and Cancer cannot be truly inherited, but certain alleles weaken the normal control points that prevent cancer, and this causes cancer to appear earlier in life.

question

Which of the following women would be most likely to benefit from genetic testing for breast cancer?

answer

--->> a. a 25-year-old woman whose mother, aunt, and grandmother had breast cancer b. a healthy 75-year-old woman with no family history of breast cancer c. a 40-year-old woman who has a cousin with breast cancer d. a 55-year-old woman whose older sister was just diagnosed with breast cancer e. All women can benefit from genetic testing for breast cancer.

question

How do the two alleles of the CFTR gene in a lung cell differ?

answer

They are inherited from different parents

question

What is true of a single human liver cell?

answer

There are 46 chromosomes present,here are two alleles for each gene, and there is one allele on each chromosome

question

Which is true of a single human gamete?

answer

There is one allele on each chromosome

question

What is the genotype of a person with cystic fibrosis?

answer

The genotype includes two mutant CFTR genes, one each on the homologous chromosomes for chromosome 7.

question

A diploid cell of baker's yeast has 32 chromosomes. How many chromosomes are in each of its haploid spores?

answer

16

question

In diploid organisms, having two homologues of each chromosome can be beneficial if one allele of a gene encodes a nonfunctional protein. Can haploid organisms survive the presence of nonfunctional alleles?

answer

No, because there is only one allele for the gene in each cell, and the nonfunctional allele has no other allele to mask it.

question

Why is it possible for two healthy parents to give birth to a child with a genetic defect such as cystic fibrosis?

answer

CF is only evident in individuals with two mutant alleles; a healthy parent could carry both a defective allele and a normal copy and be healthy.

question

A human female has _____ chromosomes in each skin cell and ______ chromosomes in each egg.

answer

46, 23

question

A woman is heterozygous for the CF-associated gene (the alleles are represented here by the letters A and a). Assuming that meiosis occurs normally, which of the following represent eggs that she can produce?

answer

A and a

question

What accurately describes meiosis?

answer

contains two rounds of division (meiosis I and meiosis II) and ends with four gametes that are not the same genetically

question

Meiosis differs from mitosis in the ________

answer

number of chromosomes in each ending cell

question

One of the purposes of meiosis is to _________

answer

reduce the chromosome number in each cell by half

question

Besides recombination, what other event in meiosis increases the genetic diversity of the gametes?

answer

the random line-up and separation of maternal and paternal chromosomes

question

An alien has 82 total chromosomes in each of its body cells. The chromosomes are paired, making 41 pairs. If the alien's gametes undergo meiosis, what are the number and arrangement (paired or not) of chromosomes in one of its gametes?

answer

41 unpaired chromosomes

question

If meiosis were to fail and a cell skipped meiosis I, so that meiosis II was the only meiotic division, how would you describe the resulting gametes?

answer

diploid cells with 23 pairs of chromosomes

question

Children often have many of the phenotypes of their parents because ______

answer

they inherit half of their genetic material from each parent

question

Women can inherit alleles of a gene called BRCA1 that puts them at higher risk for breast cancer. The alleles associated with elevated cancer risk are dominant. Of the genotypes listed below, which carries the lowest genetic risk of developing breast cancer?

answer

bb

question

In order for a child to develop cystic fibrosis,

answer

a sperm carrying a CF allele must fertilize an egg that also has that allele.

question

Assume that Emily (who has CF, a recessive disease (aa)) decides to have children with a man who does not have CF and who has no family history of CF. What combination of gametes can each of them produce, and what is the probability that they will have a child who is a carrier for CF?

answer

Emily: aa and man: AA; 100% probability

question

Use the following information for this question: Phenylketonuria is considered to be an inborn error of metabolism. It is a recessive genetic condition in which the enzyme that breaks down the amino acid phenylalanine is defective or missing. Testing of all newborns allows this condition to be detected at birth. A special diet that severely minimizes phenylalanine (e.g., by avoiding diet sodas and most usual sources of protein) can treat the condition. In this scenario, two carriers of both cystic fibrosis and phenylketonuria have a child. What is the probability that the child will have both cystic fibrosis and phenylketonuria?

answer

6.25%

question

Use the following information for this question: Phenylketonuria is considered to be an inborn error of metabolism. It is a recessive genetic condition in which the enzyme that breaks down the amino acid phenylalanine is defective or missing. Testing of all newborns allows this condition to be detected at birth. A special diet that severely minimizes phenylalanine (e.g., by avoiding diet sodas and most usual sources of protein) can treat the condition. In this scenario, two carriers of both cystic fibrosis and phenylketonuria have a child. What is the probability that the child will have cystic fibrosis and be a carrier for phenylketonuria?

answer

12.5%

question

What does it mean to say that a person is a heterozygous carrier for a genetic disease?

answer

That person does not show symptoms of the disease if the disease allele is recessive

question

What does it mean to say that a person has a heterozygous genotype for a disease gene and no disease phenotype?

answer

This disease has a recessive inheritance pattern and this person is a carrier of the disease because the dominate allele masks the recessive phenotype.

question

Which of the following statements applies to tissues?

answer

Multiple cell types are present, each tissue has a specific function, and cells within a tissue cooperate.

question

You shed skin cells every day. How are those cells replaced?

answer

by mitotic division and differentiation of tissue stem cells

question

Why don't engineered bladders get rejected by the patient's immune system when they are implanted?

answer

Engineered bladders are grown from the patient's own cells; no immune response occurs because the implanted cells have the same surface markers.

question

Organs can perform unique functions that differ from those that the tissues, from which they are made, can perform individually. Why is this?

answer

Tissues cannot form the same shapes that organs can; organs therefore have more functions than tissues.

question

What is(are) the advantage(s) of receiving an organ transplant versus growing a replacement organ from one's own cells?

answer

less chance of organ rejection & no need to wait on a transplant list

question

Why does a recipient of a liver transplant have a high risk of bacterial infections?

answer

because transplant recipients have to take drugs that suppress their immune system

question

Would it be sufficient to just replace the neurons in someone who suffered nervous tissue damage? Why or why not?

answer

No, replacement neurons must also make the correct connections with cells in their surroundings.

question

Why is engineering a bladder more challenging than engineering skin?

answer

A bladder has so many more cell types, A bladder has a three-dimensional shape, A bladder requires a scaffold on which to grow

question

Why do scientists pursue several methods to get stem cells to grow into specific tissue types?

answer

Some methods may prove successful, whereas others may not pan out and Each method or approach used in stem cell research adds to our knowledge of how stem cells work.

question

Relative to one of your liver cells, one of your skin cells __________.

answer

has the same genome (that is, genetic material) and has a different pattern of gene expression

question

Is the genome of stem cells larger than that of specialized cells?

answer

No, because all of a person's cells have the identical set of genes in their genome.

question

What is the biological function of stem cells?

answer

to replenish the stock of existing stem cells, to replace cells that have been damaged, to differentiate into specific cell types

question

Cellular differentiation, or cell specialization, results from __________.

answer

the "turning off" of some genes and the "turning on" others

question

Which is the correct order of gradual specialization, from least to most, that cells undergo during development?

answer

multipotent; pluripotent; totipotent

question

How are embryonic stem cells different from somatic stem cells?

answer

Embryonic stem cells can develop into an unlimited array of cell types while somatic stem cells can become only limited cell types

question

Why would cancer chemotherapy limit the ability of somatic stem cells to perform the normal cell turn-over in a tissue?

answer

Cancer chemotherapy blocks mitosis.

question

In somatic cell nuclear transfer (SCNT), the nucleus from a specialized cell is inserted into ______

answer

an enucleated egg

question

What is the technology used to de-differentiate somatic cells so they become like embryonic stem cells called?

answer

induced pluripotent stem cell technology

question

Which of the following is not a way in which researchers have obtained embryonic stem cells in the United States?

answer

implanting an SCNT egg into a woman and removing the embryo before it becomes a fetus

question

An adult stem cell from bone marrow is most useful in treating _______

answer

a disorder affecting the development of white blood cells

question

What makes the treatment of leukemia by stem cell replacement different from regenerative therapy, where stem cells are injected?

answer

Regenerative therapy seeks to make stem cells differentiate into cell types they would not normally become, whereas leukemia treatment is only focused on bone marrow stem cells becoming more marrow cells.

question

For what purpose do scientists insert "reprogramming" genes into differentiated cells?

answer

to convert the differentiated cells into pluripotent stem cells

question

What are the differences between drugs and supplements?

answer

Drugs: require FDA approval based on clinical trials and have a single active ingredient Supplements: Does not require FDA approval, often make claims without clinical trials, and have dried materials containing many different compounds

question

Why do cells divide?

answer

our bodies are dynamic structures, cells divide to produce new cells or replace cells that have been lost (divide for growth, repair, and reproduction)

question

Phases of the cell cycle

answer

-Interphase: majority of cell cycle, normal cell functions (not a resting phase) -G1: growth includes protein synthesis, cell increases in size and increases in # of organelles -S: DNA replicated, chromosomes duplicated (becomes a chromatid- each copy is a chromatid) -G2: proteins necessary for cell division synthesized -Mitotic stage: -mitosis: nuclear division -cytokinesis: cytoplasm division

question

Phases of mitosis

answer

-prophase -prometaphase -metaphase -anaphase -telophase *see notes for descriptions in detail

question

Properties of Cancer cells

answer

-Tumor: mass resulting from uncontrolled cell growth -Benign tumor: cells are restricted to the tumor, non invasive -malignant tumor: cancerous cells spread, invasive, establish additional tumors (metastasis)

question

Cancer Therapy

answer

-Radiation may be used to destroy defective cells -Tumors may be removed surgically -Follow up with chemotherapy (treatment based on the use of chemicals (usually drugs) -supplements have not really shown to help with cancer alone but can compliment chemotherapy when combined

question

Cell division occurs frequently in which biologic process?

answer

Embryo development and wound healing

question

If a cell has 20 chromosomes during G1, how many during G2? how many after mitosis if it has not gone through cytokinesis?

answer

40, 40

question

Cystic fibrosis

answer

mutations of the gene CFTR on chromosome 7, loss of 3 nucleotides resulting in a loss of CFTR gene, the severity may be determined by additional modifier genes

question

Recessive traits

answer

condition where one allele masks the effect of another allele

question

dominant traits

answer

an allele which masks the effects of the recessive trait (represented by a capital letter)

question

Tracking inheritance

answer

when an individual has one dominant and one recessive allele, they are called heterozygous; when an individual has two dominant alleles, they are called homozygous dominant; genetic diseases may be dominant or recessive; the risk of disease depends on the combination of alleles inherited from a person's parents

question

Homologous chromosomes:

answer

have the same genes but not necessarily the same alleles

question

If an organisms somatic cells are diploid then its gametes are likely to be:

answer

Haploid

question

The ear that was growing on the back of the mouse is:

answer

cartilidge tissue in the shape of a human ear

question

Tissues are:

answer

groups of cells that perform a specific function

question

Organs are:

answer

a. all found inside of the body b. parts of cells c. only found in animals d. comprised of one cell e. none of the above answer: E

question

Stem cells are:

answer

found in multiple parts of the body

question

Heart cells and skin cells are very different why is this?

answer

heart cells and skin cells express different genes

question

What are two types of cells that constantly need to be replaced?

answer

Skin cells and red blood cells

question

Somatic Bone marrow stem cells:

answer

can differentiate into only a few types of cells

question

______ cells are non-dividing whereas ______ cells can differentiate into many types of cells.

answer

Quiescent; pluripotent

question

a zygote is an example of a _____ cell

answer

totipotent

question

What is the cause of cellular differentiation?

answer

differential gene expression

question

Embryonic stem cells recovered from a blastocyst are:

answer

pluripotent

question

Cellular differentiation:

answer

can be reversed to create pluripotent stem cells in the lab

DNA Components and Chromosomes

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