WorksheetsUnit 11 Mendelian Genetics
Total questions: 22
Worksheet time: 22mins
In the 1800’s, Gregor Mendel studied the genetics of pea plants. His findings led him to develop the laws of heredity. One of these laws is known as the Law of Segregation. During fertilization, gametes from each parent combine to create a zygote. The Law of Segregation explains that during their formation, each gamete receives one allele for each of the parent's traits.
What process creates the gametes described in the Law of Segregation?
Mitosis
Meiosis
Cell Differentiation
Gene Expression
The shape of red blood cells is governed by a codominant allele. Normal red blood cells are described as being round or donut shaped. All of the red blood cells in individuals with two copies of the normal allele (NN) are round. The mutated form of this gene causes red blood cells to be sickle-shaped. These thin, elongated red blood cells can get stuck in blood vessels and block blood flow and oxygen from parts of the body. All of the red blood cells in individuals with two copies of the mutated allele (SS) are sickle-shaped. People who inherit one normal allele and one mutated allele (NS) have some round red blood cells and some sickle-shaped blood cells.
What are the chances of a child having both round and sickle-shaped red blood cells if one parent has all sickle-shaped cells and the other parent has both round and sickle-shaped blood cells?
0%
50%
75%
100%
Differentiation occurs when a stem cell changes to a more specialized type of cell. Stem cells are cells that can differentiate into many other types of cells, depending on the needs of the organism.
What is the reason a stem cell can differentiate into many other types of cells, such as blood cells, nervous cells, and fat cells?
Different sections of DNA (Genes) get turned on depending on the type of cell needed.
Cells receive different amounts of energy, which determines what they will become.
Each stem cell has different DNA that determines what what they change into.
Mutations in the DNA of different stem cells determine what they change into.
Most bacteria prefer to use glucose as a carbon source. However, if glucose is not available, the bacteria can use the sugar lactose as a carbon source instead. In order for bacteria to use lactose, they must make an enzyme to break down the lactose. This enzyme is called lactase. If there is no lactose, the bacteria will not make the enzyme.
This production of lactase is an example of —
an organism
adapting to its
surroundings
genetic variation
between
organisms
regulation of gene expression
cellular respiration in prokaryotes
Mud minnows are a type of fish found along the Atlantic coast of the United States. Embryos of these fish normally develop with two eyes. However, scientists have found that if eggs are placed in 100 mL of seawater mixed with 6 g of magnesium chloride, the fish embryos will only have one eye.
What is a possible explanation for this phenomenon?
This phenomenon is caused by gene expression regulated by chemicals.
This phenomenon is caused by a mutation caused by the saltwater
This phenomenon is caused by having different DNA nucleotides.
This phenomenon is caused by a change due to too high water temperature.
What molecule is responsible for providing information to the ribosomes where proteins are built?
DNA, since it
contains the
genetic
information to
build proteins
mRNA, since it
carries information from the nucleus
to the ribosome
Amino acids, since they are bonded
together to form a protein
tRNA, since it is
responsible for
transporting amino acids to the ribosome
A variety of corn can produce yellow or white seeds. Yellow is dominant. White is recessive.
If an ear of corn contains only white corn, it must be —
homozygous
recessive
heterozygous
recessive
heterozygous
dominant
homozygous
dominant
In humans, freckles (F) on the skin are dominant to no freckles (f). If two parents are heterozygous for the trait, which statement below best describes their chances of having a child with no freckles?
If the parents already have three children with freckles, then they are more likely to have a child without freckles.
Every time they reproduce, the parents have a one in four chance of having a child without freckles.
It would be extremely rare for the freckled parents to have a child without freckles because freckles are dominant.
The parents will have three children with freckles before they have a child without freckles.
A bacterium that is exposed to a toxin in its environment can make an enzyme to neutralize the toxin. The bacterium controls protein synthesis to produce the enzyme by activating an inducible operon. The activation of the operon causes the transcription of the mRNA that codes for the enzyme. The mRNA is then translated to make the specific enzyme needed to neutralize the toxin.
What phenomenon is demonstrated in this example?
Evolution by natural selection
Cell differentiation by prokaryotes
Adaptation to external stimuli
Regulation of gene expression
Escherichia coli is a bacteria species that is able to break down lactose, a complex sugar found in milk. When lactose enters the cell through passive transport, a repressor chemical is removed from a section of the DNA and multiple proteins are synthesized. One type of protein embeds in the cell membrane to facilitate the transport of high volumes of lactose into the cell. Another protein plays the role of an enzyme that breaks down lactose into two simple sugars, glucose and galactose. When the amount of lactose in the cell decreases, the repressor chemical binds to the DNA again to block the production of proteins.
Which step in the process best represents the regulation of gene expression in Escherichia coli?
Lactose enters the cell through passive transport.
A protein is synthesized to facilitate transport of lactose.
An enzyme breaks down lactose into two simple sugars.
A repressor binds to the DNA when lactose levels are low.
Which of the following is not an effect of meiosis?
Causes more genetic diversity in sexually reproductive species
Reduces the number of offspring affected by genetic mutations
Ensures the same number and types of chromosomes in each individual
Improves the chances of species survival due to variability in individual strengths
Why is it important to reduce the number of chromosomes in half when forming gametes for sexual reproduction?
Gametes have a single function which requires less DNA to perform the function compared to somatic cells.
A reduction in the number of chromosomes reduces the chances for mutations that would affect the offspring.
The offspring will have the correct number of chromosomes when the sperm and egg are joined.
The chromosomes in gametes are already replicated strands of DNA which returns the number of chromosomes to the original amount.
Insulin is a protein that maintains homeostasis in the amount of sugar in the blood. When there are high levels of sugar in the blood, cells in the pancreas generate more insulin and release it into the blood. This causes muscle cells and fat tissue to absorb sugar. When there are low levels of sugar in the blood, the production of insulin is slowed.
What is the most likely cause of the phenomenon described?
Pancreas cells have more copies of the insulin gene than other cells.
Glucose has a chemical reaction with blood cells to create insulin.
The body has a surplus of insulin stored in the pancreas and releases it when needed.
The expression of the insulin gene is regulated by blood glucose concentration.
Which of the following events in the protein synthesis process demonstrates that gene expression is regulated?
mRNA exits the nucleus
mRNA is transcribed from DNA
mRNA is translated by a ribosome to form a polypeptide
mRNA transcription is stopped in the nucleus
Cell differentiation can occur when different proteins are manufactured as a result of cells producing different types of ―
DNA
genes
RNA
amino acids
What is the role of DNA in the differentiation of the cells within an organism?
Each cell has a different set of DNA that determines the traits of the cell and causes differentiation.
Each cell has the same DNA, so DNA does not play a role in differentiation.
Cells do not use the same sections of DNA in the same proportions, at the same time in development, leading to differentiation.
DNA mutates differently in each cell depending on the environment causing each cell to differentiate over time.
A specialized cell cycle known as meiosis plays a significant role in sexual reproduction. Which of the following is not an important result of this specialized cell division process?
Genetic variation
Production of sex cells
Reduction of genetic material in daughter cells
Growth
Meiosis plays a more significant role in reproduction than mitosis in which of the following ways?
Increasing the variability of genetic information
More efficiently using energy in the cell division process
More rapidly reproducing and growing
Increasing the process of asexual reproduction
Instructions found in DNA control a less-specialized cell’s potential to change in size, shape, and function. The process which controls the future of a cell is —
cell transformation
RNA translation
cell differentiation
DNA transcription
Having freckles is a dominant trait in humans. A girl has freckles, but her brother does not.
What genotypes could result in these children with different traits?
FF and FF
ff and ff
Ff and Ff
FF and ff
In a population of bees, long wings are dominant over short wings. Bees with long wings are —
heterozygous only
homozygous
dominant only
heterozygous or
homozygous
recessive
heterozygous or
homozygous
dominant
In guinea pigs, the allele for rough coat (R) is dominant over the allele for smooth coat (r). A heterozygous guinea pig and a homozygous recessive guinea pig are mated.
Which of the following would be the percentages of possible offspring phenotypes?
100% rough coat
100% smooth coat
50% rough coat and 50% smooth coat
75% rough coat and 25% smooth coat
