Bio 101 Exam 3 – Flashcards
Unlock all answers in this set
Unlock answersquestion
An individual's DNA is
answer
identical in all cells
question
Liver cells and kidney cells do different tasks because they
answer
contain the same DNA but use different genes.
question
Where are chromosomes located in eukaryotic cells?
answer
nucleus
question
What is a genome?
answer
the complete set of genetic material encoded within the DNA of an organism
question
Which of the following statements does NOT accurately describe human DNA?
answer
Females receive two X chromosomes from their mother.
question
Which of the following base pairs would be found in normal DNA?
answer
A and T
question
In eukaryotic cells, chromosomes are located in
answer
the nucleus.
question
A single large DNA molecule wrapped around proteins is called a
answer
chromosome.
question
Each human cell has _____ pairs of chromosomes.
answer
23
question
A laboratory technique used to replicate, and thus amplify a specific DNA segment, is called
answer
polymerase chain reaction
question
An enzyme that "reads" the sequence of a DNA strand and helps to add complementary nucleotides to form a new strand during DNA replication is
answer
DNA polymerase.
question
True or False. DNA replication is said to be semiconservative because each newly made DNA molecule has one original and one new strand of DNA.
answer
true
question
Generally, what is the final product of gene expression?
answer
a protein
question
A protein is made up of a chain of __________.
answer
amino acids
question
______amino acids tend to be found folded inside a protein, whereas _______ amino acids interact with water on the outside of the protein.
answer
hydrophobic; hydrophilic
question
What determines a protein's function?
answer
the three-dimensional shape of the folded protein
question
Heating a protein can cause it to denature, or unfold. What do you think would happen to the function of a protein in a denatured state?
answer
The protein would not be functional because the three-dimensional shape dictates protein's function.
question
______is the product of transcription, and _______ is the product of translation.
answer
mRNA; a protein
question
How do the redundant properties of the genetic code protect humans from some mutations?
answer
Some mutations will not change the amino acid coded by the mRNA codon.
question
Why is recombinant protein production in the milk of transgenic animals an efficient strategy?
answer
because milk is secreted, so the protein can be obtained noninvasively
b. because milk is produced in relatively large quantities
c. because mammary glands naturally secrete large quantities of proteins into milk
d. because milk is easier to obtain than other secretions (e.g., urine, sweat, and saliva)
question
In an antithrombin-producing transgenic goat,
answer
the antithrombin gene construct is present in every cell and expressed only in mammary cells.
question
How did scientists alter the gene for antithrombin so that it could be isolated from milk?
answer
They attached the regulatory sequence of the goat antithrombin gene to the human coding sequence of antithrombin.
question
Why are biotechnology companies eager to design genetically modified organisms to express therapeutic proteins, particularly ones that would otherwise have to be isolated from blood products (e.g., human antithrombin) or animal organs (e.g., insulin, originally isolated from pig pancreas)?
answer
Biotechnology companies want to produce therapeutic proteins in the most cost-effective way.
b. There are safety concerns when using proteins from different species or isolating proteins from humans.
c. It is difficult to collect enough of some low-abundance proteins.
question
What is a genetically modified organism?
answer
any modified organism that produces a product it does not normally make
question
What is a gene?
answer
segment of DNA that encodes at least one protein
question
If a gene is activated, what is being produced?
answer
protein
question
Alleles are alternate versions of _____ gene(s) that have ____ nucleotide sequences.
answer
the same; small differences in their
question
The coding sequence of a gene is the portion of the DNA that
answer
specifies the shape and function of a protein.
question
A mutation can cause a change __________.
answer
in the amino acid sequence of a protein
b. in the shape of a protein
c. in the way the cell cycle is regulated
question
DNA mutations can arise from uncorrected errors in DNA replication, inheritance, and __________.
answer
environmental insults
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
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
Which of the following statements accurately describes cancer development?
answer
It is a multistep process by which multiple mutations cause a series of events that lead to cancer.
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, as well as the accumulation of mutations in various cells
question
We would all have many more mutations in our genes if not for the __________
answer
activity of proofreading enzymes
question
How many alleles for a single trait are present in each human cell?
answer
2
question
What is an example of a mutation in an allele?
answer
a base change in the gene's regulatory regions
a deletion of a base within the gene
a base change in the gene coding sequence
question
An allele is
answer
an alternate version of a gene
question
Which of the following statements applies to tissues?
answer
Multiple cell types are present.
b. Each tissue has a specific function.
c. 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
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
Relative to one of your liver cells, one of your skin cells __________.
answer
has the same genome (that is, the same genetic material),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
b. to replace cells that have been damaged
c. 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
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
Somatic stem cells are found in
answer
adult tissues
