Biology Unit 7 Test Review
When during the cell cycle are chromosomes visible?
ONLY during cell division
Homozygous
an organism that had two identical alleles for a trait
Homozygous alleles are
an organism that has two identical alleles for a trait
Which group do flowering plants belong?
angiosperms
Plant's stamen consists of
anther and filament
Self pollination is when the pollen from one plant lands on the stigma in the same plant. This process eventually produces many offspring genetically identical to itself and is called -
asexual reproduction
In rabbits, the allele for black coat is dominant over the allele for a brown coat. If a rabbis homozygous for brown fur, what is the genotype?
bb
Potatoes can reproduce asexually. Each sprout on a parent potato can grow into a new potato plant.How does the genetic material in the sprout compare to the parent potato?
both the sprout and parent potato have the same genetic identity
Dominant alleles are indicating using
capital letters
Meiosis
cell division resulting in 4 haploid gametes formed from 1 diploid parent cell
On a pedigree shapes represents ...
circles: female, square: male
A cross between a purebred animal with red hairs and a purebred animal with white hairs produces an animal that has both red hairs and white hairs. What type of inheritance pattern is involved?
co dominance
Sex chromosomes are written as
coefficients on the sex chromosomes: X
What happens during prophase I of meiosis?
crossing over in which alleles are exchanged
Which of the following describes an event that results from mitosis?
daughter cells that are identical to the parent cell
Describes meiosis I ...
division of homologous chromosomes
Tallness (T) is a dominant trait in pea plants, and shortness (t) is recessive. How can you determine the genotype of a tall pea plant?
do a test cross with a short pea plant
Suppose a person is a carrier for a genetic disorder. Which of the following phrases about this person is true?
does not have the disorder but can pass it on
A recessive trait's genotype can be seen as:
ee
In animals, female traits are passed down to offspring from
eggs
A particular peach tree produces peaches that are more resistant to diseases than other peaches. What method would reproduce these exact peaches?
ensure that the peach tree reproduces asexually
Identical twins who are raised apart can have differences that last a lifetime. This is evidence that
environment and genotype interact to affect phenotype
Non-disjunction
failure of homologous chromosomes to separate evenly during meiosis resulting in production of zygotes w abnormal chromosome numbers
egg
female gamete
Ovaries
female gonads, produces estrogen that causes breast development, body changes, and menstration
Pistil
female reproductive organ of a flower
Purpose of gametes?
find other gametes
Which of the following describes part of a phenotype?
having freckles
In the case of codominant alleles, a plant that is homozygous for red flowers that is crossed with a plant that is homozygous for white flowers will produce flowers that are
red and white spotted
Non-Mendelian Inheritance
refers to any pattern of inheritance in which traits do not segregate in accordance with Mendel's laws (ex. incomplete dominance, codominance, multiple alleles, polygenic traits, sex-linked traits)
Regeneration
replacement of destroyed tissue by the same kind of cells, can generate new organisms
Sexual reproduction
reproduction involving the union or fusion of a male and a female gamete
Describe asexual reproduction in organisms?
requires two parents
Meiosis II
second time the cell divides, divides the number of chromosomes in half - making it a haploid cell
In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. This is an example of
sex linked trait
If a stigma receives pollen from another flower of the same species, the flower is cross pollinated. Cross pollination is an example of
sexual reproduction
What type of sexual reproduction is fusing gametes?
sexual reproduction
Which type of reproduction leads to increased genetic variation in a population?
sexual reproduction
Which of these statements describes crossing over?
sister chromatids exchange genes to increase genetic variety
Meiosis 2 is similar to Mitosis because
sister chromatids separated during anaphase
Chromosome
sister chromatids; DNA that has wrapped around histone proteins and condensed
Chromosomes
sister chromatids; DNA that has wrapped around histone proteins and has condensed
Pollen tube
slender tube that grows from a pollen grain down the style that penetrates the ovule and releases male gametes
Meiosis in males is called
spermatogenesis bc it produces sperm
Stigma
sticky portion at the top of the style where pollen grains frequently land
Do flowers contain both male and female parts?
yes
What is the genotype ratio of all monohybrid crosses of two heterozygote parents ( e.g., Pp x Pp)?
1:2:1
DNA content of a single cell at metaphase of meiosis 2 would be:
1X
If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase
2X
What is the probability that a yellow (Y) and wrinkled pea (r) will appear from a cross of Yyrr x YyRr?
3/8
The muscle cells of an elephant contain 62 chromosomes. How many chromosomes are in an elephant egg cell?
31
The gene for tallness (T) in a pea plant is dominant over the gene for shortness (t). The Punnett square below shows the cross between two tall pea plants (Tt). What is the phenotypic ratio of the offspring produced as a result of the cross?
3:1
What is the phenotype ratio of all monohybrid crosses of two heterozygote parents (e.g. Pp x Pp)?
3:1
The gene for tallness (T) in a pea plant is dominant over the gene for shortness (t). In a cross between two heterozygous parent pea plants, we can predict that what percentage of the offspring will be heterozygous?
50%
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A woman who does not have hitchhiker's thumb marries a man who is heterozygous for hitchhiker's thumb. What is the probable genotypic ratio of their children?
50% Hh: 50% hh
If AaBb is crossed with AaBb, what is the phenotypic ratio?
9:3:3:1
punnett square
A chart that shows all the possible combinations of alleles that can result from a genetic cross
Codomiance
A condition in which neither of two alleles of a gene is dominant or recessive.
dihybrid cross
A cross that examines the inheritance of two different traits, chance of inheriting two sets of alleles at the same time
Pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family.
Pollen
A fine dust that contains the sperm of seed-producing plants
Ovary
A flower structure that encloses and protects ovules and seeds as they develop.
binary fission
A form of asexual reproduction in which one cell divides to form two identical cells.
Testosterone
A male sex hormone produced by the testes that signals physical changes at puberty and controls the maturation of sperm
Gene
A segment of DNA on a chromosome that codes for a specific trait
gene
A segment of DNA on a chromosome that codes for a specific trait
Ovule
A structure that develops within the ovary of a seed plant and contains the female gametophyte.
Dominant
Allele that is expressed and masked the recessive allele
Which of the following best explains why meiosis results in greater genetic diversity than mitosis?
During meiosis, chromosomes assort themselves independently of each other, which allows for more different possible combinations of chromosomes
Why would the offspring resulting from fertilization have more differences than the offspring resulting from budding
Each parent provides half of its offspring during fertilization, unlike during budding.
A dominant trait's genotype can be seen as:
Ee or EE
True or False: Males can be carriers of sex linked traits?
False
Interphase consists of ...
G1, S, and G2 phases
Which pair includes a phase of the cell cycle and a cellular process that
G2 phase AND preparation for mitosis
Mendel hypothesized that reproductive cells have only one factor for each inherited trait. This hypothesis is supported by which observation?
Haploid cells are produced by meiosis.
Females who are carriers have what genotype?
Heterozygous
Which of the following describes an organism with two different alleles for a trait?
Heterozygous
Anaphase I
Homologous chromosomes separate and move towards the poles of the cell.
Asexual reproduction
One parent produces a genetically identical offspring by mitosis
asexual reproduction
One parent produces a genetically identical offspring by mitosis.
Alleles for the A and B blood cell antigens are codominant. The condition where no antigens are present on the blood cells (type O blood) is a recessive trait. Which set of parents can most likely produce a child with type O blood?
One parent with heterozygous type A blood, and the other parent with type O blood , In order for a recessive condition to be expressed, the individual must have two recessive alleles, one from the mother and one from the father. C is the only condition in which both parents possess an O allele to pass on to the offspring.
Recessive genes are expressed under which of the following conditions?
Only in the absence of dominant genes for the same trait.
Metaphase I
Pairs of homologous chromosomes align on the equator of the cell. Shortest phase.
X-linked dominant
Pattern of genetic transmission: both M and F affected; no M-to-M transmission; affected M passes trait to all daughters, every generation; affected F passes trait to both sons and daughters; a single mutant allele can produce the disease.
Fertilization
Process in sexual reproduction in which male and female reproductive cells join to form a new cell
Which of the following accurately identifies all the possible combinations of genes in the offspring of two parents heterozygous for the gene with a dominant form (R) and a recessive form (r)?
RR, Rr and rr only
In a particular species, red hair (H) is a dominant trait for hair color over white hair (h). The male parent is HH and the female parent is Hh. What color hair does the female parent have?
Red
When during the cell cycle is a cell's DNA replicated?
S Phase
filament
Supports the anther
Hemophilia is a sex linked, recessive trait. Which of the following describes the probability of hemophilia in the offspring of a man who does not have hemophilia and a woman whose father is hemophiliac?
None of their daughters will have hemophilia, sex linked traits are only present on sex chromosomes. Hemophilia is an X-linked chromosome so a father who does not have hemophilia must donate a non-hemophilia gene on the X chromosome he contributes to his daughter. For a girl to have a sex linked condition, both of her X chromosomes have to have the allele for that condition.
If a corn plant has a genotype of Ttyy, what are the possible genetic combinations that could result in a single grain of pollen from this plant?
Ty, ty
How many divisions does Mitosis have? Meiosis?
Mitosis 1 and Meiosis 2
Compare the processes of mitosis and meiosis.
Mitosis involves one division cycle and results in diploid daughter cells, while meiosis consists of two division cycles and results in haploid gametes (a new individual)
Oogenesis
The production of egg cells (ovum)
Cell cycle
The regular sequence of growth and division that cells undergo
Telophase II
The spindle fibers disappear, and a nuclear membrane forms around each set of chromosomes.
Examples of asexual reproduction
mitosis and binary fission
The two main stages of cell division are called
mitosis and cytokinesis
menstruation
monthly shedding of the uterine lining, releases one egg per month
Unlike the traits studied by Mendel, most traits are produced by genes with
multiple alleles
Major problem of asexual population stimulation ...
mutation will get passed to all future offspring since their offspring are identical, no diversity
Which of these is a characteristic of asexual reproduction?
no genetic variety (its identical ... a clone)
In a genotype for plant height, such as Tt, what does each letter represent?
one allele
allele
one of a number of different forms of a gene
Chromatid
one of two identical "sister" parts of a duplicated chromosome
chromatid
one of two identical "sister" parts of a duplicated chromosome
Mitosis occurs ..
only if the cell is large enough and the DNA undamaged
Meiosis in females is called
oogenesis bc it produces ova (eggs)
Plant fertilization occurs when the pollen meets the egg in the
ovary
Which part of the flower develops into a fruit?
ovary
Meiosis is a type of cell division in which germ cells produce haploid cells. Where does meiosis occur?
ovary cells
A chart that traces the phenotypes and genotypes within a family is called a
pedigree
A plant that is homozygous for red flowers is crossed with a plant that is homozygous for white flowers. In the case of incomplete dominance, the flowers of the offspring will be a. red and white.
pink only
Examples of sexual reproduction
plants, animals, people (lots of genetic variation)
Human height occurs in a continuous range because it is affected by the interaction of several genes, making it a
polygenic trait
Seminal fluid
produced by seminal vesicles and prostrate gland; combined with sperm to make semen
anther
produces pollen
Which of these is accomplished by the interaction of halpoid cells in sexually reproducing organisms?
production of a zygote with a complete set of chromosomes with genetic material from two parents
Spermatogenesis
production of sperm cells
Mitosis involves ...
prophase, metaphase, anaphase, telophase (growth of embryo)
Self pollination
the transfer of pollen grains from an anther to the stigma of the same flower or to the stigma of another flower on the same plant
self-pollination
the transfer of pollen grains from an anther to the stigma of the same flower or to the stigma of another flower on the same plant
There are 2 sex chromosomes (1 pair and its the last pair). How many chromosomes are not sex chromosome?
there are 44 autosome chromosomes (that's 22 pairs)
A bacterium can reproduce quickly by slitting into two cells, what do we know?
they have same amount of genetic material and are identical
What happens to sister chromatids in meiosis II?
they separate
Which of these is a function of the plant reproductive system?
to produce seeds from a fertilized egg, to make new individuals
Which of these is a function of the animal reproductive system?
to produce sperm and egg, to make new individuals, to nurture developing offspring
On a pedigree shaded shapes represent ...
traits being tracked
Meiosis involves ...
two successive cell divisions with no replication of genetic material between them (formation of egg and formation of sperm)
One of the parents of a child has phenylketonuria (PKU), which is caused by recessive alleles. The other parent does not have the PKU alleles. What is the chance that the couple will have a child with PKU?
0% , for a recessive condition to be passed on, the offspring must inherit one allele for that condition from each parent. In this case, the father has no PKU allele.
Recessive
An allele that is masked when a dominant allele is present
recessive
An allele that is masked when a dominant allele is present
Heterozygous
An organism that has two different alleles for a trait
heterozygous
An organism that has two different alleles for a trait
genotype
An organism's genetic makeup, or allele combinations.
Phenotype
An organism's physical appearance, or visible traits.
phenotype
An organism's physical appearance, or visible traits.
Autosome
Any chromosome that is not a sex chromosome
Budding
Asexual reproduction in which a part of the parent organism pinches off and forms a new organism
vegetative propagation
Asexual reproduction that uses parts of plants to grow new plants
fragmentation
Asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.
Spore formation
Asexual reproductive process in which an organism forms a special cell called a spore.
Anaphase II
Centromeres divide, sister chromatids moved to the opposite poles of the cell. Each one splits into two pieces.
At the beginning of mitosis ...
Chromosomes condense (DNA wraps around proteins to condense.
Prophase I
Crossing over occurs .. segments of non-sister chromatids break and reattach to the other chromatid .. this creates diversity of offspring traits (X Shaped structures)
A gene mutates in a type of bacteria. When these bacteria reproduce asexually, this mutation can only be inherited by
Direct descendants of the bacteria
Why is meiosis a significant part of sexual reproduction?
Meiosis allows offspring to inherit genes of both parents, allowing for genetic diversity.
Sex linked inheritance
Inheritance of a genetic trait located on the sex chromosomes
What is the significance of meiosis to sexual reproduction?
It produces haploid gametes, with half the number of chromosomes.
During which phase in the cell cycle does mitosis happen?
M Phase
Sperm
Male gamete (sex cell)
Homologous chromosomes move toward opposite poles of a dividing cell during:
Meiosis I
A distinguishing characteristic that can be inherited is a(n)
Trait
Test Cross
Testing a suspected heterozygote by crossing it with a known homozygous recessive
A human baby boy inherits a recessive allele from his mother. In which circumstance would he most likely show the trait coded for by the recessive allele?
The allele is on the X chromosome, males with an X linked recessive allele are expressed because there is no counterpart allele to mask the trait. Boys have XY genotype and girls have XX genotype.
Prophase II
The chromosomes and spindle fibers reappear in each new cell; nuclear envelope breaks down (no replication of genetic material in interphase)
Metaphase II
The duplicated chromosomes move to the center of the cell, each centromere attaches to two spindle fibers instead of one.
In fruit flies, the gene for eye color is located on the X chromosome, and the red eye allele [R] is dominant over the white eye allele [r]. A female fly with genotype XRXr is mated with a male fly with genotype XrY. Which statement below best describes the expected outcome of this cross?
XRY = 25%
A human cell containing 22 autosomes and a Y chromosome is:
a Sperm
monohybrid cross
a cross that examines the inheritance of only one specific trait
x linked dominant
a mode of genetic inheritance by which a dominant gene is carried on the X chromosome
Telophase I
a nuclear membrane forms around each cluster of chromosomes, cytokinesis has occurred and two haploid daughter cells are formed
X-linked recessive
a recessive disorder that is carried by the x chromosome
complete dominance
a relationship in which one allele is completely dominant over another
cross polination
a reproductive process in which pollen from one plant is transferred to the stigma of another plant
cross-pollination
a reproductive process in which pollen from one plant is transferred to the stigma of another plant
A person who has a disorder caused by a recessive allele is
homozygous for the recessive allele
A red-flowered sweet pea plant is crossed with a white-flowered sweet pea plant. All of the offspring are pink. What is the inheritance pattern being expressed?
incomplete dominance
Mendelian inheritance
inheritance of traits that follow Gregor Mendel's two laws and the principle of dominance
autosomal dominant
inheritance pattern of a dominant allele on an autosome
Autosomal Recessive
inheritance pattern of a recessive allele on an autosome
autosomal recessive
inheritance pattern of a recessive allele on an autosome
Sister Chromatids
joined copies of the original chromosome
Which of Mendel's laws best explains why genetic variations occur in offspring resulting from sexual reproduction
law of segregation
Testes
male gonads; produces testosterone that causes muscle development, hair growth, voice deepening
Eye color, hair color, and skin color are polygenic traits. Polygenic traits result from
many genes
fruits and seeds
mature ovary containing fertilized eggs of a plant
Prophase I (Meiosis)
the chromosomes condense, and the nuclear envelope breaks down; crossing over occurs
estrogen
the female sex hormone produced by the ovaries that signals certain physical changes at puberty and controls the maturation of eggs
Meiosis I
the first time the cell divides.
Half shaded shapes on pedigrees mean ...
the individual is a carrier (heterozygous)
Stamen
the male reproductive organ of a flower
Style
the narrow elongated part of the pistil between the ovary and the stigma
Incomplete dominance is observed when
the parental phenotype is blended to form a new offspring phenotype, situation in which one allele is not completely dominant over another; blending
