General Biology 1- Test 4

The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called _______ ____________.

asexual reproduction

Sexual reproduction will increase _______ variation, compared to asexual resproduction which does not have _______ variation at all.

genetic, genetic

Strictly speaking, the phrase “like begets like” refers to _______ reproduction only.

asexual

Asexual reproduction requires ___ individual(s), whereas sexual reproduction requires ___ individual(s).

one, two

With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have a _______ but not _________ combination of genes.

similar, identical

Cell division is necessary for ___________ to occur. Cell division can reproduce an ______ organism. Cell division is the basis of both ______ and _______ reproduction.

development, entire, sexual, asexual

In prokaryotes , daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them. Prokaryotic cells are generally _______ and _______ than eukaryotic cells. Most prokaryotes reproduce by ______ _______.

smaller, simpler, binary fission

Eukaryotic chromosomes differ from prokaryotic chromosomes in that they are housed in a ________-________ _______.

membrane enclosed nucleus

________ help maintain the structure and control the activity of genes.

proteins

Sister chromatids are joined together at a __________.

centromere

Prior to mitosis and after S phase, each chromosome of a eukaryotic cell consists of a pair of identical structures called ______ __________.

sister chromatids

Eukaryotic cells spend most of their cell cycle in __________.

interphase

____ ______ and ___________ of the chromosomes occurs during interphase.

cell growth, duplication

The genetic material is duplicated during the _ phase.

S

The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called ___________.

cytokinesis

Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! You realize that this cell is undergoing ___________.

cytokinesis

The phase of mitosis during which the mitotic spindle begins to form is ________.

prophase

During _________ the chromosomes line up on a plane equidistant from the two spindle poles.

metaphase

At the start of mitotic ________ the centromeres of each chromosome come apart.

anaphase

During _________ the nuclear envelope reforms.

telephase

The _________ __ _ ____ _____ is a feature of plant cell division that distinguishes it from animal cell division.

formation of a cell plate

What feature likely accounts for the difference between plant and animal cell cytokinesis?

cell walls

What must occur for a plant or animal to grow and develop normally?

They must be able to control the timing and rate of cell division in different parts of the body.

When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of _______-_________ __________.

density dependent inhibition

As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of _______-_________ __________.

density dependent inhibition

What is probably the main factor responsible for the phenomenon of density-dependent inhibition?

physical contact of cell-surface proteins between adjacent cells

Mature human neuron (nerve) cells and muscle cells are permanently in a state of ___-________.

non division

The cell cycle control system receives messages from outside the cell that influence cell division. The cell cycle control system triggers and controls major events in the cell cycle. The cell cycle system includes three key checkpoints to complete a cell cycle.

true

You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely a _________ _____.

cancerous tumor

A benign tumor differs from a malignant tumor in that a benign tumor does not ___________.

metastasize

A drug that prevents _______ _______ from forming shows the greatest promise as a cancer chemotherapy agent.

mitotic spindle

Mitosis is necessary for _______ reproduction in eukaryotes and promotes ______ ______.

asexual, tissue repair

Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are __________ ___________.

homologous chromosomes

A pair of sex chromosomes found in a human male is most like a _____ and _____.

bride, groom

In animals, _______ only occurs in the ovaries and testes. A normal human ______ has 46 chromosomes. All sexual life cycles involve an alternation of _______ and _______ stages.

meiosis, zygote, haploid, diploid

Two haploid cells fuse during _____________. _______ are haploid cells. A ______ is a fertilized egg.

fertilization, gametes, zygote

A tetrad, during anaphase I of meiosis, ______ into two pairs of sister chromatids, and one pair goes to each ____ of the dividing cell.

splits, pole

In meiosis ____ daughter cells are produced, whereas in mitosis ___ daughter cells are produced. In mitosis cytokinesis occurs ____, whereas in meiosis cytokinesis occurs _____.

four, two, once, twice

All the events unique to meiosis occur during meiosis. In _______, the chromosomes replicate only once in the preceding interphase. Mitosis provides for ______ and ______ ______.

I, mitosis, growth, tissue repair

Both mitosis and meiosis are preceded by __________.

interphase

Independent orientation of chromosomes at metaphase I results in an ________ in the number of possible ____________ __ _______________.

increase, combination of characteristics

At a chiasma, two __________ __ _________ __________ are attached to each other.

homologous or sister chromatids

Karyotyping can reveal ___________ in chromosome number. 

alterations

A karyotype is most like photographs of every couple at a high school prom. 

true

Down syndrome is the most ______ serious birth defect in the United States. People with down syndrome usually have a _______ ____ ____ than normal. _______ __ is the cause of down syndrome.

common, shorter life span, trisomy 21

______________ occurs when members of a chromosome pair fail to ________.

nondisjunction, separate

_________ ______ commonly demonstrates polyploidy.

flowering plants

How many generations does it take to develop a new plant species by polyploidy?

one

If a chromosome fragment breaks off and then reattaches to the original chromosome but in the reverse direction, the resulting chromosomal abnormality is called an _________.

inversion

Cancer is not usually inherited becasue the chromosomal changes in cancer are usually confined to _______ cells.

somatic

A skin cell of a red fox has 34 chromosomes. You look at the cell under a microscope and see that it has 34 chromosomes and one nucleus. Several hours later, you look at the same cell again and see that it has double the amount of DNA and one nucleus. A little while later, you see that it has 68 chromosomes and two nuclei. What stage of the cell cycle was this cell in when you viewed it at each time point? 

G1, G2, and telephase

You have two flasks (labeled A and B) that each contain an equal population of normal animal cells. You place flask A in a machine called a shaking incubator, which shakes the flask at 37C and keeps the cells moving so as to not allow them to adhere to the bottom of the flask. Flask B is allowed to sit in an incubator (without shaking) at 37C. If you let the cells in each flask grow for a week, which of the following results are you most likely to observe?

suspended or floating cells do not reproduce

Sister chromatids separate during ________ of mitosis and ________ __ of meiosis.

anaphase, anaphase II

The formation of a zygote and a sperm is an unpredictable event is an example of what?

random fertilization

Random combinations of paternal and maternal chromosomes end up in gametes is an example of what?

independent orientation

An allele on the paternal chromosome 18 ends up on the maternal chromosome 18 is an example of what?

crossing over

Jacobsen syndrome, which can cause heart defects, intellectual deficiencies, and bleeding disorders, is caused by a deletion of the terminal end of chromosome 11. What method could you use to determine whether an individual has Jacobsen syndrome?

perform a karyotype

You are a medical student and are reviewing a case study about a past patient. The patient was 4 feet 8 inches tall at age 38, was unable to have children, and had cognitive impairments. The patient also had an irregular number of chromosomes. What diagnosis would you give the patient?

Turner syndrome

What is the theory of pangenesis developed by Hippocrates? Particles called ________, which originate in each part of an organism’s body, collect in the sperm or eggs and are passed on to the next generation.

pangenes

Mendel conducted his most memorable experiments on ____.

peas

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as ____-_________.

true breeding

The hybrid offspring of an F1 cross are the __  generation. The offspring of two different varieties are called _______. The parental plants of a cross are the _ generation.

F2, hybrids, P

The expressed physical traits of an organism are called its _________. The genetic makeup of an organism constitutes its ________. _______ are alternate forms of a gene. 

phenotype, genotype, alleles

Research since Mendel’s time has established that the law of segregation of genes during gamete formation applies to all _________ ___________ organisms.

sexually reproducing

The alleles of a gene are found at the same _____ on __________ chromosomes.

locus, homologous

The phenotypic ratio resulting from a dihybrid cross of two heterozygous individuals showing independent assortment is expected to be what?

9:3:3:1

Mendel’s ___ __ ___________ __________ states that each pair of alleles (chromosomes) segregates independently of the other pairs of alleles during gamete formation.

law of independent assortment

Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision). We can conclude that the alleles for color and vision _________ _____________ during gamete formation.

segregate independently

A _________ is a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest.

testcross

Using six-sided die, what is the probability of rolling either a 5 or a 6?

2/3

The probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple’s first-born child will be female and that their second-born child will be male?

25%

A carrier of a genetic disorder who does not show symptoms is most likely to be ____________ for the trait and able to transmit it to the offspring.

heterozygous

Most genetic disorders of humans are cause by _________ alleles.

recessive

Most people afflicted with recessive disorders are born to parents who were ___ affected at all by the disease.

not

Why are dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders?

People with lethal dominant alleles die before reproductive age

Amniocentesis and chorionic villus sampling allow for ___________ and ___________ _______ of the fetus so that it can be tested for abnormalities.

karyotyping, biochemical testing

___ and _____________ are usually reserved for pregnancies with higher than usual risks of complication. __________ _______ has no known risk. Results from chorionic villus sampling come ______ than those from amniocentesis.

CVS, amniocentesis, ultrasound imaging, faster

Genetic testing before birth requires the collection of _____ _____. Carrier testing helps determine whether a person carries a potentially _______ disorder. The screening of newborns can catch __________ disorders right after birth.

fetal cells, harmful, inheritant