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53 Cards in this Set

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Which of the following statements is true?
D. all of the above
A. Sexual reproduction involves two parents, with each parent supplying a set of genetic information.
B. Sexual reproduction leads to greater genetic variability than does asexual reproduction.
C. Asexual reproduction involves only one parent, and only one set of genetic information.
The structures that contain an organism's DNA are called:
chromosomes
Most prokaryotic organisms reproduce mainly by the process of:
binary fission
Why is binary fission classified as asexual reproduction?
because the genetically identical offspring inherit their DNA from a single parent
During cell division, the DNA is in a coiled up and compacted form called ___. When the cell is not dividing, the DNA is in long thin fibers called ___.
chromosomes, chromatin
How many chromosomes are there in typical human body cells?
46
Before a cell can begin dividing by mitosis, it must:
duplicate all of its chromosomes
When a chromosome is duplicated, the result is two copies of the chromosome called ___, which are joined together at the ___.
sister chromatids, centromere
What is the function of cell division?
all of the above
A. to enable a multicellular organism to grow to adult size
B. to replace worn-out or damaged cells
C. to keep the total cell number in a mature organism relatively constant
Approximately how many cells are there in the adult human body?
60 trillion
In which phase do eukaryotic cells spend most of their time?
interphase
In which phase are chromosomes duplicated?
interphase
In which subphase does DNA replication occur?
S
In which phase is the cytoplasm divided in two?
cytokinesis
In which phase of mitosis to the chromosomes condense and become visible, and the nuclear envelope breaks into fragments.
prophase
In which phase of mitosis are the centromeres of all the chromosomes lined up across the middle of the cell?
metaphase
Which of the following occurs during anaphase of mitosis?
only B and C are correct
B. sister chromatids separate
C. daughter chromosomes begin to move toward opposite poles of the cell
Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
a cell plate forms
Most cells will only divide if they have a solid surface on which to attach and anchor themselves. Why is this beneficial to the organism?
This prevents cells that become separated from their normal surroundings from dividing inappropriately.
Animal cells, when growing on a surface in a tissue culture, will multiply to form a single layer, and usually stop dividing when they touch one another. This is called:
density-dependent inhibition
What causes density-dependent inhibition?
when the cells become crowded, the supply of growth factors in the immediate environment is depleted
Which of the following describes the cell-cycle control system?
there are checkpoints in the cycle, and the cycle stops unless “go-ahead” signals are applied
Why do cancer cells divide excessively?
cancer cells do not have a properly functioning cell-cycle control system
The spread of cancer cells beyond their original site is called:
metastasis
Which of the following is a difference between benign and malignant tumors?
benign tumors do not metastasize
Which of the following originate in the external or internal coverings of the body, such as skin or lining of the intestine?
carcinomas
Which of the following arise in tissues that support the body, such as bone and muscle?
sarcomas
Which of the following are cancers of blood-forming tissues, such as bone marrow, spleen, and lymph nodes?
leukemias and lymphomas
Which of the following cancer treatments uses drugs to disrupt cell division?
chemotherapy
Which of the following terms describes a “typical” body cell, with the 2n number of chromosomes
somatic cell
What are homologous chromosomes?
chromosomes that carry genes for the same inherited characteristics
The particular place on a chromosome that contains a particular gene is called the:
locus
The 22 pair of chromosomes that do not include the sex chromosomes are called the:
autosomes
Two chromosomes in a nucleus that carry loci for the same traits in the same positions on the chromosome, but can specify different versions of the same traits, constitute a pair of:
homologous chromosomes
Which of the following describes how we inherit our chromosomes?
one of each of the homologous chromosomes comes from our father, and the other of each of the homologous chromosomes comes from our mother
In humans, cells whose nuclei contain two homologous sets of chromosomes are called:
diploid
In humans, cells whose nuclei contain only one set of chromosomes are called:
both B and C are correct
B. haploid
C. gametes
Egg and sperm cells are called:
gametes
A fertilized egg is called:
zygote
A zygote is:
diploid
Meiosis is the process that:
produces haploid gametes in diploid organisms
How does meiosis differ from mitosis?
In meiosis four daughter cells are produced, while in mitosis two daughter cells are produced.
Which of the following increases genetic diversity?
both A and B are correct
A. independent sorting of homologous chromosomes to daughter cells during meiosis
B. crossing over of corresponding segments between homologous chromosomes
The place where homologous chromatids are attached to each other during crossing-over is called a:
chiasma
An orderly picture of magnified images of stained chromosomes is called:
a karyotype
How does the karyotype of a human female differ from the karyotype of a human male?
females have two X chromosomes, and males have X and Y chromosomes
If a karyotype indicates trisomy 21, which of the following are true?
only A and B are correct
A. the person has three copies of chromosome 21 instead of two copies
B. the person has Down syndrome
What is the major factor that increases the risk of having a child with Down syndrome?
age of the mother, especially if over 35
The failure of a chromosome pair to separate during meiosis is called
nondisjunction
The loss of a fragment from a chromosome is called:
deletion
If a fragment of a chromosome joins the homologous chromosome, so that the chromosome now has two copies of that fragment, it is called:
duplication
The reattachment of a fragment to the original chromosome, but in the reverse direction, is called:
inversion
The attachment of a chromosomal fragment to a nonhomologous chromosome is called:
translocation