Biology
Cell reproduction
Pre test
1. Most mammals have diploid body cells and haploid gametes. During
__________, chromosomes from haploid gametes combine, and a __________
zygote is formed.
A. implantation, diploid
B. fertilization, haploid
C. fertilization, diploid
D. implantation, haploid
2. When environmental conditions change, it is more likely that at least some
members of a species will survive if
A. the species reproduces asexually.
B. the species requires very specific environmental conditions.
C. there is variation among the members.
D. the members are genetically identical.
3. The carp fish has 104 chromosomes in its body cells. When the fish's body cells
divide by mitosis, how many chromosomes will each daughter cell have?
A. 312
B. 208
C. 104
D. 52
4. Genes can mutate through replication error or through contact with a mutagen.
What can be a result of a mutation?
A. The mutated gene can cause the organism to undergo speciation.
B. The mutated gene is able to perform a new function.
C. The mutated gene can become a separate organism.
D. The mutated gene can become pathogenic to other organisms.
5. Examine the diagram below:
Ciliates are protists that are able to reproduce both sexually and asexually. Both of
these forms of ciliate reproduction are shown in the diagram.
Which type of reproduction is represented in Process A?
A. fission
B. budding
C. fragmentation
D. sexual reproduction
6. Examine the diagram above:
Ciliates are a type of protist that are able to reproduce both sexually and
asexually. Both of these forms of ciliate reproduction are shown in the diagram.
Which type of reproduction is represented in Process B?
A. fragmentation
B. budding
C. sexual reproduction
D. fission
7. Which of the following is a source of genetic variation in sexually-reproducing organisms?
A. translation
B. mitosis
C. meiosis
D. all of these
8. Suppose four different species live in close proximity to one another within an
ecosystem. Species W reproduces through fragmentation. Species X reproduces
sexually. Species Y reproduces through budding. Species Z reproduces through
fission.
Which species will most likely have the most genetic diversity among their
offspring?
A. Species X
B. Species Z
C. Species Y
D. Species W
9. What is occurring in the diagram below?
A. Genes are replicating.
B. Alleles are independently assorting.
C. Sister chromatids are separating.
D. Segments of DNA are crossing over.
10. Suppose a person found a starfish and cut the starfish up into several pieces
before throwing the starfish back into the water. Each of the pieces of the
starfish grew into a new starfish. What form of reproduction did the starfish
exhibit?
A. fission
B. sexual reproduction
C. fragmentation
D. budding
11. Bacteria, many plants, protists, and simple animals are able to reproduce
asexually. Which of the following is an advantage of asexual reproduction over
sexual reproduction?
A. Asexual reproduction takes more energy to perform than sexual reproduction.
B. Asexual reproduction enables a single organism to produce both eggs and sperm.
C. Asexual reproduction causes the gene pool of a species to rapidly change.
D.
Asexual reproduction allows organisms to produce many offspring in a short period of time.
12. When a body cell divides through the process of mitosis, the chromosomes in the
daughter cells
A. are identical to the chromosomes of the parent cell.
B. represent only the healthiest chromosomes from the parent cell.
C. are only half of the chromosomes in the parent cell.
D. are formed when chromosomes from the parent cell cross over.
13. Asexual reproduction takes less energy to perform than sexual reproduction.
Why is this most likely the case?
A. Specialized gamete cells do not need to be produced during asexual reproduction.
B. Unlike sexual reproduction, there are several different types of asexual reproduction.
C. Unlike sexual reproduction, parts of the parent's body are used to form the new
offspring in asexual reproduction.
D. Asexual reproduction occurs over a longer period of time than sexual reproduction.
14. During meiosis, each diploid parent cell divides
produces
haploid daughter cells.
and
A. twice; two
B. once; two
C. once; four
D. twice; four
15. Offspring that are produced through sexual reproduction have more genetic
diversity than offspring that are produced through asexual reproduction. Why is
this the case?
A. Sexual reproduction involves the mixing of genes from two separate individuals.
B. Sexual reproduction involves the production of a clone.
C. Sexual reproduction involves the process of mitosis.
D. Sexual reproduction involves the rearranging of a single parent's genetic code.
16. How do mutations lead to genetic variation?
A. by producing random changes in an organism's genetic code
B. by changing the organism's appearance
C. by changing the organism's behavior
D. by changing the way that the organism reproduces
17. During embryonic development, cells __________ and become more
__________.
A. decrease in number, generalized
B. decrease in number, specialized
C. increase in number, generalized
D. increase in number, specialized
18. Alex is studying a population of fifty organisms that belong to the same species.
Some of the organisms have dark spots, some have light spots, some have no
spots, and some have stripes.
How does this species reproduce, most likely?
A. using sexual reproduction
B. using asexual reproduction
C. the species does not reproduce
D. using both sexual and asexual reproduction
19. Data for the hatching of sea turtle eggs is shown below.
Group # Incubation temp Number of eggs Moon phase Tide Female
(°C)
%
1
26.0
79
New moon
High
10.0
2
27.4
67
Full moon
Low
15.0
3
28.5
59
First quarter High
30.0
4
29.5
42
Last quarter High
72.5
5
30.3
108
New moon
Low
83.0
According to the table, what factor can be said to influence the gender of sea
turtle hatchlings?
A. tide
B. phase of moon
C. number of eggs
D. temperature
20. Which of the following is a disadvantage of sexual reproduction?
A. Sexually-reproducing organisms reproduce too quickly.
B. Sexually-reproducing organisms are genetically-unique.
C. A sexually-reproducing organism cannot reproduce without finding a mate.
D. Species that reproduce sexually are unable to adapt.
21. In sexually reproducing organisms, mutations can be passed on to the
organism's offspring if the mutation occurs in...
A. any of the parent's cells found in the reproductive system only.
B. germ cells only.
C. Mutations in parent cells are never transferred to their offspring.
D. any of the parent's cells.
22.
Rachel grows pea plants in her backyard. Some of the pea plants have purple
flowers, whereas others have white flowers. What does this indicate about
Rachel's pea plants?
A. The pea plants all have identical genes.
B. The pea plants have genetic variation.
C. The pea plants can only reproduce asexually.
D. The pea plants cannot reproduce.
23. Which population is likely to have the most genetic variation among its
members?
A. a population whose members have many different traits
B. It is impossible to identify genetic variation within a population.
C. a population whose members are exactly the same
D. a population whose members are very similar to each other
24. In the gastrula stage of embryonic development, shown in the diagram below,
three layers of cells form—the ectoderm, the endoderm, and the mesoderm.
The mesoderm cells will eventually differentiate into the
A. skin and nervous system of the organism.
B. organism's digestive tract lining.
C. organism's muscles, blood, and reproductive organs.
D. mouth and anal opening of the organism.
25. Each pair of _________ chromosomes has genes for the same trait.
A. male
B. sex
C. homologous
D. mutated
Biology
Cell reproduction
Pre test answer sheet
____1.
____2.
____3.
____4.
____5.
____6.
____7.
____8.
____9.
____10.
____11.
____12.
____13.
____14.
____15.
____16.
____17.
____18.
____19.
____20.
____21.
____22.
____23.
____24.
____25.
Answers
1. C
2. C
3. C
4. B
5. A
6. C
7. C
8. A
9. D
10. C
11. D
12. A
13. A
14. D
15. A
16. A
17. D
18. A
19. D
20. C
21. B
22. B
23. A
24. C
25. C
Explanations
1. In the process of fertilization, a haploid egg cell fuses with a haploid sperm cell. The
nuclei of the cells fuse, and the homologous chromosomes pair up. The result is that a
diploid, one-celled zygote is formed.
The zygote cell divides and becomes an embryo through normal mitotic division.
2. When environmental conditions change, it is more likely that at least some members of
a species will survive if there is variation among the members. This is because the
variant organisms within the species are able to respond differently to the
environmental changes.
3. Body cells undergo a type of division called mitosis. During mitosis, the daughter cells
produced are identical to the parent cell. So, daughter cells resulting from mitosis in a
carp fish will have 104 chromosomes.
5. In Process A, the ciliate is reproducing by fission, the separation of a parent into two or
more individuals of about equal size.
4. Mutations generally do one of two things. First, a mutation can lead to the loss of
function of a gene. Second a mutation can lead to a new function. Mutations can have
various affects on the organism. Some mutations have no affect at all. Some mutations
change the morphology of the organism. Some mutations change the biochemical
reactions within the organism. If the mutation is passed on to offspring and is beneficial
to the offspring’s survival, eventually the descendants of the organism with the original
mutation may undergo speciation.
6. In Process B, two ciliates pair and exchange genetic materials. Meiosis then occurs in
the micronuclei, one of which will then develop into a zygote. Meiosis is a process that
occurs in sexual reproduction.
8. Sexual reproduction allows genes from two parents to be mixed into different
combinations within their offspring. This creates more genetic diversity among the
members of a species. So, species X. will have the most genetic diversity among its
offspring.
7. In sexually-reproducing organisms, meiosis helps contribute to genetic variation.
Meiosis is the process by which sexually-reproducing organisms produce gametes, or
sex cells. Meiosis produces gametes that are unique from each other and from the
"parent genome". The gametes will be passed on to future offspring.
9. In the diagram, segments of DNA from homologous chromosomes are crossing
over. This process, which occurs during Prophase I of meiosis, happens randomly and
frequently. In fact, it can even occur at more than one place along the same
chromosome.
Meiosis and crossing-over are important processes because they contribute to the
genetic variation found in organisms that undergo sexual reproduction.
10. Fragmentation is a type of reproduction in which the body breaks into several pieces.
Some or all of these fragments then develop into complete adults when missing parts
are regrown.
11. Asexual reproduction takes less time and energy to perform than sexual reproduction.
However, asexual reproduction results in populations with little genetic diversity.
12. Body cells divide through the process of mitosis. In mitosis, the daughter cells produced
are identical to the parent cell. In particular, they have the same number of
chromosomes as the parent cell, and these chromosomes are identical copies of the
chromosomes in the parent cell.
In contrast, gametes (sex cells) are produced through the process of meiotic cell
division. In meiosis, the daughter cells are different from the parent cell. The daughter
cells not only have only half of the chromosomes present in the parent cell, but the
process of crossing over during Prophase I creates new, nonidentical chromosomes.
13. Asexual reproduction takes less energy than sexual reproduction because the organism
does not have to expend energy to find a mate or produce specialized reproductive cells.
14. There are two stages of nuclear division during meiosis. During the first stage (meiosis
I), the number of chromosomes in the diploid parent cell double. Then, homologous
chromosomes pair with one another and split into two daughter cells. During the second
stage (meiosis II), the sister chromatids separate to produce four haploid daughter
cells.
Since the assortment of alleles during meiosis is independent and random, over 8
million different combinations of chromosomes are possible in humans. (Humans have
46 chromosomes. The possible number of combinations is given by the formula 2 n,
where n = 23, the haploid number of chromosomes.)
15. Individuals produced through sexual reproduction are more genetically diverse than
individuals produced through asexual reproduction because sexual reproduction occurs
from the fusing of two specialized cells that each contains different genetic material.
The fusing of the cells, called fertilization, produces a unique combination of genes not
found in any other organism (except in the case of identical twins).
16. A mutation is a random change in a cell's genetic code due to a variety of causes.
The change can be small and insignificant, or it can be major. Mutations can be passed
on to offspring through reproduction, thus increasing the genetic variation within a
population.
17. After an egg cell fuses with a sperm cell, a zygote forms. The zygote begins to divide,
and the number of cells increases.
Although the zygote cell undergoes mitotic division, no cell growth occurs between
divisions. Where there was once one cell, many cells develop. However, the volume
does not change, so the cell size decreases upon each division.
When the embryo enters the gastrula stage, cells begin to specialize. Three different
layers of cells develop—endoderm, ectoderm, and mesoderm. These cells later
differentiate further into the highly specialized types of cells that make up a complete
organism—muscle, nerve, blood, bone, and skin cells.
18. Since sexual reproduction results in genetic variation, populations of sexuallyreproducing organisms usually have a variety of different traits. In this case, the
organisms have a variety of color patterns, so the species most likely uses sexual
reproduction.
19. In sea turtles, development of embryos is influenced by temperature.
The gender of many invertebrate animals is determined by sex-determining
chromosomes. However, the gender of sea turtle offspring is determined by the sand
temperature during incubation.
When the sand is below 29 degrees, more males are produced. When the sand
temperature is above 29 degrees, more females are produced.
20. Sexual reproduction combines the genetic material of two individuals. As a result, a
sexually-reproducing organism cannot reproduce if it cannot find a mate.
21. In sexually reproducing organisms, mutations can be passed on to the organism's
offspring if the mutation occurs in germ cells (i.e. egg and sperm).
22. Genetic variation occurs when alleles are randomly sorted during sexual reproduction.
Since each offspring receives a different combination of alleles from the parent
organisms, phenotypic diversity results.
Rachel's pea plants are exhibiting phenotypic diversity because some of the plants have
purple flowers, whereas others have white flowers. This indicates that the pea plants
have genetic variation.
23. The array of physical traits within a population is generally a good indicator of the
amount of genetic variation within the population. So, the greater the variety of
observable features within a population, the greater the genetic variation within the
population.
24. Ectoderm cells differentiate to form the skin and nervous system of the organism.
Endoderm cells eventually become the organism's digestive tract lining.
Mesoderm cells become the organism's muscles, blood, and reproductive organs.