biology exam 3
Which of these is NOT a carcinogen?
all of the above are carcinogens
In colon cancer, a polyp is __________.
a small benign tumor
What is the chromosome composition of a normal human male?
44 autosomes, 1 X chromosome, and 1 Y chromosome
A____is a lump of abnormal cells that, although growing out of control, remains at its original site.
Benign Tumor
What do DNA and RNA have in common?
Both are composed of nucleotides.
An individual with a malignant tumor is said to have___
Cancer
In a story similar to the virgin birth of a shark at the Reef HQ Aquarium in Queensland, Australia, zookeepers at the Chester Zoo in England reported that a Komodo dragon laid a clutch of eggs that hatched into healthy young. The zookeepers claimed that the offspring were a result of asexual reproduction. What evidence would confirm this claim?
DNA testing confirmed that all of the DNA of the Komodo dragon babies was derived from their mother.
Identify a difference between embryonic and adult stem cells from the following list.
Embryonic stem cells are undifferentiated; adult stem cells are partially differentiated.
Similar homeotic genes help direct embryonic development in nearly every eukaryotic organism examined. These similarities suggest that these homeotic genes arose very early in the history of life, and that the genes have remained remarkably unchanged.
Evolution
The cell cycle is a series of events that occur in which order?
G1, S, G2, mitosis, cytokinesis
Suppose a cDNA has the sequence CTTAGGA. What is the corresponding mRNA sequence?
GAAUCCU
Every cell in your body was produced through successive rounds of mitosis, starting from the zygote. Mitosis exactly duplicates chromosomes. Therefore, every cell in your body has the same DNA as the zygote.
Information flow
Some proteins that trigger metabolic changes in cells are broken down within a few minutes or hours. This selective breakdown of proteins allows the cell to adjust the kinds and amounts of its proteins in response to changes in its environment.
Interactions within biological systems
A___is an abnormally growing mass of cells that is actively spreading through the body.
Malignant Tumor
___is the spread of cancer cells from their site of origin to other sites in the body.
Metastasis
Which of the following enzymes is responsible for RNA synthesis?
RNA polymerase
Eukaryotes have more complex modes of control, includingthe packing of chromosomes, ______ (which can produce several mRNAs from a single gene), and the control of translation.
RNA splicing
Translation converts the information stored in ________ to ________.
RNA... a polypeptide
Some eukaryotes consist of multiple cells specialized for different tasks within the organism. Gene regulation allows this specialaztion. A prokaryote, being a single cell, does not require this elaborate regulation of gene expression.
Relationship of structure to function
Which event occurs during anaphase?
Sister chromatids become separate chromosomes.
Consider the accompanying figure, which outlines cloning by nuclear transplantation. Why does the clone NOT resemble the surrogate mother?
The DNA for the clone comes from the genetic donor, not the surrogate.
How are the cells in different body tissues able to perform different functions?
The cells exhibit different patterns of gene expression.
Which one of the following combinations of sex chromosomes results in Turner syndrome?
XO
The backbone of DNA consists of ________.
a repeating sugar-phosphate-sugar-phosphate pattern
The mutation would be most harmful to the cells if it resulted in ________.
a single nucleotide change in the middle of an intron
Male tortoiseshell cats ______.
are likely to be exceedingly rare and very likely to be sterile since normal male cats are XY
A characteristic of the human immunodeficiency virus (HIV) that makes it different from some other RNA viruses is that it __________.
can synthesize DNA from an RNA template
An understanding of gene regulation mechanisms has led to several interesting and important applications. For example, the loss of gene regulation can result in _______ , or out-of-control cell growth.
cancer
Homologous chromosomes ________.
carry genes controlling the same inherited characteristics
The structure where sister chromatids are joined is called the ________.
centromere
Which of the following is an animal virus?
chicken pox virus
Most of an organism's DNA is carried by its __________.
chromosomes
Although all of the cells in your body contain a complete set of DNA, different cells have different functions because __________.
different genes are switched on and off in each type of cell
Which of the following cells is least differentiated?
embryonic stem cells
Besides having practical purposes, a shared genetic vocabulary also reminds us of the kinship that connects all life on Earth.
evolution
_____ is a carcinogen that promotes colon cancer.
fat
The individual represented in this karyotype is a _________.
female with Down syndrome
A single cell passing through meiosis and cytokinesis results in the formation of __________.
four haploid cells Submit
All organisms must regulate ________ by turning genes on and off in different cells at different times
gene expression
What type of chemical bond joins the bases of complementary DNA strands?
hydrogen
Mad cow disease is caused by ________.
infectious proteins called prions
Every cell contains a DNA "cookbook" that provides directions on how to make and maintain that cell. When a cell reproduces, it must duplicate its DNA, providing one copy to the new offspring cell while keeping one copy for itself.
information flow
The process of DNA replication requires the cooperation of more than a dozen enzymes and other proteins.
interactions with biological pathways
Non-coding DNA sequences are referred to as ________.
introns
After an RNA molecule is transcribed from a eukaryotic gene, portions called __________ are removed and the remaining __________ are spliced together to produce an mRNA molecule with a continuous coding sequence.
introns ... exons
Which is most likely to cause the development of a six-legged frog?
mutation of homeotic genes
If a woman's breast cancer is treated in its earliest stages, her chance of survival for five years or more is __________.
nearly 100%
What name is given to a gene that causes cancer?
oncogene
How many active X chromosomes are there in each cell of a female mammal?
one
In an operon, the ______ acts as an on/off switch.
operator
In prokaryotic cells, related genes may be organized into _______ , which can be turned on and off as a single unit
operons
Watson and Crick realized that the chemical properties of each kind of base in DNA dictated the base pairings. Each base has protruding chemical groups that can best form hydrogen bonds with only one appropriate partner.
pathways that transform energy
As shown in the accompanying figure, plant cell cytokinesis differs from animal cell cytokinesis because ________.
plant cells form a cell plate and animal cells do not
Which of the following is the correct order for the four main stages of mitosis?
prophase, metaphase, anaphase, telophase
A benign tumor is a condition in which tumor cells __________.
remain confined to their original site
What type of protein binds to silencers to prevent gene expression from occurring?
repressors
________ can produce new live individuals
reproductive cloining
Cells communicate with one another via ________.
signal transduction pathways
If a strand of DNA has the sequence GACTTA, transcription will result in a(n) ________.
single RNA strand with the sequence CUGAAU
A typical human body cell with 23 pairs of chromosomes is called a __________.
somatic
_________ can produce potentially therapeutic stem cells
therapeutic cloning
How many nucleotides make up a codon?
three
Thymine and cytosine differ from adenine and guanine in that ________.
thymine and cytosine are single-ring structures, whereas adenine and guanine are double-ring structures
Which of the following processes occurs in the cytoplasm of a eukaryotic cell?
translation
A DNA microarray is used to __________.
visualize patterns of gene expression