Biology Chapter 5
In a dihybrid cross involving two autosomal traits on different chromosomes in which the parents are purebred for the opposite forms of both traits, how many of the offspring would be expected to be homozygous recessive for both traits.
1 out of 16
5.8 If a cell had 12 chromosomes at the beginning of meiosis 2, how many would each daughter cell have after the completion of meiosis 2?
12
5.13 Assuming complete dominance, what is the expected ratio of genotypes of the offspring following the cross of two heterozygotes?
1:2:1
5.7 How many chromosomes did you inherit from your father?
23
Assuming complete dominance, what is the expected ratio of phenotypes of the offspring following the cross of two heterozygotes?
3:1
How many chromosomes and chromatids would a typical human cell have after duplication but before mitosis?
46 chromosomes; 92 sister chromatids
Human white blood cells are often multinucleated (in other words, have more than one nucleus). How many chromosomes would be present in a human white blood cell with two nuclei?
92
What is the chromosome abnormality that causes Down Syndrome?
A nondisjunction results in a person with an extra copy of chromosome 21.
The cell theory states that
All living things are made up of cells
What is a carrier?
An individual who is heterozygous for a recessive allele
The following F1 cross is made BBGg x Bbgg. Which is not a possible outcome in the F2 generation?
BbGG
5.3 When are the chromosomes of a cell duplicated
Before a cell divides
Which process requires DNA to undergo duplication before it can proceed?
Both Mitosis and Meiosis
An individual can be homozygous for a trait, which means
Both of their alleles carry the same information.
5.5 + 5.6 How does cytokinesis occur in animal cells?
By the formation of a cleavage furrow
DNA plus its associated proteins is called a ________.
Chromatin
Which is not part of mitosis?
Cytokinesis
If it were to be stretched out, the DNA in one of your cells would be taller than you. How does such a large quantity of DNA fit within the nucleus of one of your cells?
DNA is associated with proteins that compact the DNA to form a package called chromatin.
Somatic cells are______
Diploid (2n)
A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short fin wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?
Do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous.
Imagine that eye color is determined by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is____ that allele for orange eyes.
Dominant to
Imagine that five hypothetical genes are arranged on a chromosome in the following order: G--H--I--J--K. Which two genes are most likely to have a crossover occur between them?
G and K
Gorillas have 48 chromosomes. How does the number of chromosomes in a gorilla sperm compare with that of a human sperm?
Gorilla sperm have one more chromosome than human sperm
A testcross is performed to determine if a specific individual is a carrier. The result generate 50/50 ratio of phenotypes. The test subject is therefore
Heterozygous
When does the cell plate form during cell division?
In the middle of plant cell mitosis
What is Mendel's law of independent assortment?
Independent assortment means that each pair of alleles segregates independently of the other pairs of alleles.
5.10 + 5.11 What does not generate genetic variation during sexual reproduction?
Independent assortment, Crossing over, and Random fertilization
5.4 During the Phase of the cell cycle are the chromosomes duplicated
Interphase
Cells spend most of their lives in?
Interphase
When I say a flower is "purple," what have I described?
Its phenotype
In a human, which of the following could be identified by the use of a karyotype?
Klinefelter syndrome, where a male has two X and Y chromosomes.
Genes located near one another on the same chromosome are often inherited together. These are called
Linked genes
Since an XO female can survive but an OY male cannot, what can we conclude about X and Y chromosomes?
Males need at least one X and Y chromosomes
5.9 What produces four daughter cells?
Meiosis
What produces genetically unique daughter cells?
Meiosis
Chromosomes are often represented as an X, with two sister chromatids attached at the centromere. Do chromosomes always look like an X?
No, chromosomes only look like an X following DNA replication, and before cell division; the rest of the time, they only have one sister chromatid each.
Is the number of chromosomes in each cell of an organism a good indicator of the complexity of that organism?
No, the number of chromosomes does not indicate how complex an organism is. Submit
Which of the following is the correct sequence of events during mitosis?
Nuclear membranes dissolves, chromosomes line up, sister chromatids split, nuclear membrane forms.
Assuming complete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?
Pink
What process involving cell division results in daughter cells that are NOT identical to the parent cell?
Sexual reproduction
What specifically separates during anaphase of mitosis?
Sister Chromatids
The inheritance pattern for red-green color blindness is different for males compared to females. Red-green color blindness is much more common in males than in females. What does this suggest about the gene for red-green color blindness?
The gene for this trait is located on the X chromosome.
what is different between two alleles for the same gene?
The info they carry
Define Mendel's law of independent assortment.
The inheritance of one character has no effect on the inheritance of another character.
5.5 + 5.6 What is cytokinesis?
The stage of the cell cycle after the cell has divided its DNA and during which the cytoplasm gets divided
What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape?
a dihybrid cross
A homozygous milk chocolate Easter bunny is crossed with a homozygous dark chocolate Easter bunny. Assuming dark chocolate is dominant over milk chocolate, which traits will the offspring express?
all dark
Genes are located on ________.
chromosomes
What happens during cytokinesis?
cytoplasm divides
Recessive disorders related to genes found on the X chromosome but not on the Y are more common in ________.
females
If mitosis makes somatic cells, what does meiosis make?
gametes
What type of cells undergo mitosis?
gametes
What specifically separates during meiosis 1?
homologous chromosomes
The offspring produced via asexual reproduction are genetically ________ to the parents.
identical
If a woman with curly hair and a man with straight hair have a child with wavy hair, the gene for this characteristic for hair shows _______
incomplete dominance
When does crossing over occur?
prophase I of meiosis I
What specifically separates during meiosis 2?
sister chromatids
What is crossing over?
the exchange of homologous chromosomes
5.12 The recessive trait is expressed in an individual when____
the individual has two recessive alleles.
When one cell goes through cell division, it produces ________.
two identical cells
Like mitosis, meiosis involves duplication of the chromosomes before division starts. However, there are __________ rounds of cell division during meiosis and __________ during mitosis.
two; one
If genes are described as "sex linked," then they are ________.
typically on the X chromosome
Upon fertilization, the egg and sperm fuse to form a single cell called a(n) ________.
zygote
