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Bio 101 Exam II Review Session 14 October 18, 2016
SI Leader: Janet Van De Stroet
How to be successful tonight
Go through the learning objectives and write out what you know about each. Then, search in the notes for clarification and other details that you may have missed or did not know.
Pay close attention to anything in bold, underlined or italicized
Ask questions if you do not understand.
Which chapter do you need the most review on?
7 Cell division
9 Patterns of Inheritance
10 Chromosomes and Human Genetics
How many SI sessions have you attended since exam I?
A sunburn causes skin cells to be replaced as they are lost from the surface of the skin. This replacement process represents an example of
meiosis I and II.
none of the above
I don’t know
Describe the difference between
1. Chromatin vs chromatid
2. haploid vs. diploid
3. Somatic cells vs. sex cells
4. Autosomes vs. sex chromosomes
Consider a cell that begins meiosis with 30 total chromosomes. How many chromosomes will be present in each resulting daughter cell by the time the division process reaches metaphase II?
___________ is more efficient, while ________ creates more genetic diversity.
Binary fission, mitosis
Binary fission, meiosis
Chromosomes connected by a centromere are called a homologous pair
When examining the rapidly dividing cells of the onion root tip, you see a cell whose replicated chromosomes are visible and are arranged in approximately the same size and shape as the nucleus, but there is no nuclear envelope. What stage of mitosis is this cell in?
Cells undergo mitosis for many reasons. Which is not a valid cause
Describe crossing over
What is it
When does it occur
What is the benefit of it occurring
The alleles of a gene are found at ____ chromosomes
The same locus on non-homologous
Different loci on homologous
Different loci on non-homologous
The same locus on homologous
In a cell where 2n=4. How many pairs of homologous chromosomes would be present in a cell undergoing metaphase II?
I don’t know
During the first meiotic division (Meiosis I) what happens?
Homologous chromosomes separate.
The chromosome number becomes haploid.
Crossing over between homologous pairs occurs.
Paternal and maternal chromosomes assort randomly
All of the above occur
What are the advantages and disadvantages of sexual and asexual reproduction?
This is a somatic cell. What is it’s haploid number?
An animal whose 2n=32 is always more complex than an animal whose 2n= 16
One minute paper
Explain how the chromosomal content changes through the main stages of meiosis
Most of the cell cycle is spent in _______.
Which is not a function of meiosis?
Reduce the chromosomal content
Separate sister chromosomes
Create new genetic combinations
All of the above are functions of meiosis
Describe the relationship of positive and negative growth regulators in regards to controlling cell growth and division.
What factors can increase human susceptibility to cancer?
exposure to hormones
all of the above
Describe the three main steps of cancer development
What are the steps
What is happening in the steps
When is the tumor benign and when is it malignant
When does the tumor become cancerous
Which of the following would not lead to increased risk of cancer?
Mutations that increase the activity of proto-oncogenes
Mutations that decrease the activity of tumor suppressor genes
Loss of p53 activity
All of the above increase cancer risk
Why is it more common for a person beyond middle age to have an increased risk for cancer?
Older cells have a harder time producing new cells.
Proto-oncogenes and tumor suppressor genes will have a longer time to accumulate mutations.
Genes can no longer repair themselves and will fall to mutations.
Hereditary mutations will occur after this age to cause cancer.
Oncogenes and tumor suppressor genes reduce the number of mutations.
Which of the following statements regarding genes is false
Genes are located on chromosomes.
Genes consist of a long sequence of DNA.
Genes contain information for the production of a single protein.
In sexually reproducing species, each cell contains a single copy of every gene.
A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color for this plant?
The observable traits of an organism are its ________.
Albinism is caused by a recessive autosomal allele. A woman and man, both normally pigmented, have an albino child together. For this trait, what is the genotype of the parents?
It depends on the sex of the child
It is unknown because not enough information provided.
Both Homozygous recessive
A true breeding purple flower plant is crossed with a true breeding white flowered plant, you would expect to see (purple is dominant to white) ____________.
offspring with all white flowers
offspring with all purple flowers
Mixed offspring 50% purple and 50% white
Mixed offspring, with about 3 purple plants to 1 white plant
The genotypic ratio of offspring of a monohybrid cross is ______________.
75% LI 25% ll
50% Ll and 50 % ll
25% LL, 50% Ll, 25 % ll
What are the 4 types on non-Mendelian traits?
Explain each and give an example
If a child has blood type O, she could not have been produced by which set of parents?
Type A mother and type B father
Type A mother and type O father
Type AB mother and type O father
Type O mother and type O father
Coat color in one breed of mice is controlled by incompletely dominant alleles so that yellow and white are homozygous, while cream is heterozygous. The cross of two cream individuals will produce
all cream offspring.
equal numbers of white and yellow mice, but no cream.
equal numbers of white and cream mice.
equal numbers of yellow and cream mice.
equal numbers of white and yellow mice, with twice as many creams as the other two colors.
A child has blood type AB his father knows that he has blood type A what are the possibilities for the mothers genotype?
BB or AA
BB or Bi
BB or AB
BB , AB or Bi
BB or ii
In humans, the genetic commonality of height and skin tone is that they are both
regulated by the same pleiotropic gene.
strictly environmentally induced with little or no genetic component.
clear violations of Mendel’s basic laws of genetic inheritance.
controlled by multiple genes with a strong environmental influence.
cases of genes exhibiting incomplete dominance.
Genetically identical plant clones can exhibit dramatic phenotypic variation depending on the environmental conditions under which they are grown.
The observation that individuals afflicted with albinism also always have vision problems is an example of
List the phenotypic and genotypic ratios for the following scenarios
1. A purple heterozygote is crossed with a true breeding purple plant.
Assume Mendelian inheritance
2. A homozygous white chicken is crossed with a black and white chicken who exhibits co-dominance.
Which is a cause of new alleles?
Law of segregation
What is the chromosomal theory of inheritance?
Mendel's law of independent assortment states that
One allele “hides” the other allele
Alleles of the same gene are separated during gamete formation
Alleles from each parent are blended in the offspring
Each gene is inherited separately from other genes
Which is not a method that increase genetic variation in a population?
Law of independent assortment
Explain how crossing over occurs. Assume that genes A,B, and C are arranged in that order along a chromosome. From your understanding of crossing-over, do you think that A will be inherited more often with B or with C?
Why will crossing over occur more between A and C than A and B?
A and C are farther apart so the chances of crossing over somewhere between them are greater than the chances of crossing over somewhere between A and B.
What is genetic linkage?
When 2 gene alleles are often inherited together because they are close together on the chromosome
What process disrupts genetic linkage?
Crossing over, when crossing over occurs it randomly separates two genes on an allele that were linked together
Genetic linkage and Crossing over
Crossing over disrupts genetic linkage
Genes that are further apart are more likely to independently assort (be separated from each other though crossing over)
Two genes are known to be on the same chromosome, yet analysis of genetic crosses involving these genes suggests that they often assort independently. The most plausible explanation for this observation is that they are
the genes involved in causing Huntington’s disease.
genes that are especially prone to mutation.
on opposite ends of the same chromosome.
located adjacent to one another on the same chromosome.
Both members of a couple are carriers for a recessive autosomal disease allele. If the couple has four children, which of the following statements must be true?
One of the children has the disease
Two of the children are carriers of the disease
All female children have the disease
Fifty percent of the children could be carrier of the disease
Sickle-cell anemia is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man who is homozygous recessive for the sickle-cell gene fathers a child by a woman who is a carrier for sickle-cell. What are the chances their children will exhibit the disease?
Genes located right next together on the same chromosomes are referred to as ________ and generally ____________.
Linked…sort independently during meiosis
Homologous…are inherited together
Linked…do not sort independently during meiosis
Codependent…do not sort independently during meiosis
Why are Autosomal Recessive genetic disorders common in a population?
Because they can continue on in a population because carriers can pass on the disorder without being affected by it
Huntington’s disease is an autosomal dominant disease. How is it possible that this disease persists in a population?
The deadly allele can hide in heterozygous carriers.
the disease causing gene is highly affect by the environment
The disease is not controlled by one specific gene, rather there are many genes that affect whether the allele is expressed
The disease takes effect later on in life allowing affected individuals to have children and pass on the affect alleles
Which of the following statements regarding crossing-over is false?
Crossing-over disrupts the linkage between genes on the same chromosome.
Crossing-over disrupts the linkage between genes on different chromosomes.
Crossing-over produces new allelic combinations.
Crossing-over produces non-parental chromosomes.
Which of the following is not true regarding x-linked disorders?
They are found on sex chromosomes
They can be inherited by both males and females.
Females are more susceptible than males
All of the above are true
An XX individual develops as a male. Which of the following statements offers the most likely explanation?
The XX inheritance pattern represents male
The sperm did not contribute any genetic material
A piece of the Y chromosome attached to one of the X chromosomes
The egg contributed twice as many sex chromosomes compared to the average situationrease genetic variation in a population?
The XX inheritance p