Archive for June 2020

The primary role of _____ is to bind animal cells together.

11:46

The primary role of _____ is to bind animal cells together.


A) tight junctions
B) the cytoskeleton
C) plasmodesmata
D) gap (communicating) junctions
E) desmosomes


Answer: E) The primary role of desmosomes (anchoring junctions) is to bind cells together

Which of these cell junctions form a barrier to the passage of materials?

11:46

Which of these cell junctions form a barrier to the passage of materials?


A) desmosomes (anchoring junctions)
B) gap (communicating) junctions
C) plasmodesmata
D) keratin fibers
E) tight junctions


Answer: E) Tight junctions form a barrier that prevents fluids from moving between cells.

Which of these organelles produces H2O2 as a by-product?

11:45

Which of these organelles produces H2O2 as a by-product?


A) peroxisome
B) centrioles
C) nucleus
D) flagellum
E) mitochondrion


Answer: A) Peroxisomes produce hydrogen peroxide as a by-product of their metabolic processes

____ is/are identical in structure to centrioles.

11:45

____ is/are identical in structure to centrioles.


A) Mitochondria
B) Nuclear envelopes
C) Basal bodies
D) Microfilaments
E) Chromatin


Answer: C) Basal bodies and centrioles have identical structures.

Where is calcium stored?

11:44

Where is calcium stored?


A) smooth endoplasmic reticulum
B) rough endoplasmic reticulum
C) microtubules
D) centrioles
E) mitochondria


Answer: A) In addition to storing calcium, the smooth ER also plays a role in detoxification and lipid synthesis

____ are the sites of protein synthesis.

11:39

____ are the sites of protein synthesis.


A) Microfilaments
B) Peroxisomes
C) Mitochondria
D) Golgi apparatuses
E) Ribosomes


Answer: E) Ribosomes are the site of protein synthesis.

Ribosomal subunits are manufactured by the _____.

11:39

Ribosomal subunits are manufactured by the _____.


A) peroxisome
B) lysosome
C) smooth endoplasmic reticulum
D) nucleolus
E) rough endoplasmic reticulum


Answer: D) Ribosomes are manufactured by the nucleolus

The _____ is composed of DNA and protein.

11:39

The _____ is composed of DNA and protein.


A) ribosome
B) flagellum
C) centriole
D) mitochondrion
E) chromatin


Answer: E) Chromatin is composed of DNA and protein

Which of these organelles carries out cellular respiration?

11:38

Which of these organelles carries out cellular respiration?


A) chromatin
B) mitochondrion
C) smooth endoplasmic reticulum
D) nucleolus
E) ribosomes


Answer: B) Mitochondria convert the chemical energy of organic molecules to chemical energy in the form of ATP

Which of the following are common traits of chloroplasts and mitochondria?

11:34

Which of the following are common traits of chloroplasts and mitochondria?


A) Both are found in plant and animal cells.
B) Both are surrounded by a single membrane.
C) Both have their own DNA.
D) Both reproduce by meiosis.
E) Proteins for both are synthesized on ribosomes in the rough ER.


Answer: C) Mitochondria and chloroplasts contain their own DNA and ribosomes

Which one of the following statements about the endomembrane system is correct?

11:34

Which one of the following statements about the endomembrane system is correct?


A) Most of the phospholipids of the endomembrane system are synthesized in the mitochondria.
B) The endoplasmic reticulum is continuous with the plasma membrane.
C) Mitochondria function in the modification and sorting of lipids and proteins.
D) Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system.
E) Ribosomes move lipids and proteins among the different organelles of the endomembrane system.


Answer: D) Proteins that will be secreted are always enclosed by some membrane of the endomembrane system until they are secreted.

Which of the following correctly matches an organelle with its function?

11:32

Which of the following correctly matches an organelle with its function?


A) nucleus ... cellular respiration
B) mitochondrion ... photosynthesis
C) central vacuole ... storage
D) lysosome ... movement
E) ribosome ... manufacture of lipids


Answer: C) But remember, plant cells have a central vacuole, whereas most animal cells have several smaller vacuoles located throughout the cytoplasm

Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results?

11:31

Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results?


A) Only one of the two fusion proteins possesses a nuclear localization signal.
B) The cytoplasmic protein contains a nuclear localization signal.
C) One of the fusion proteins entered the nucleus by passive transport.
D) Nucleoplasmin does not have a nuclear localization signal.


Answer: A) The nuclear localization signal is only present in the fusion protein that enters the nucleus

In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules?

11:31

In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules?


A) To target the proteins to the nucleus
B) To make the proteins bigger
C) To make the proteins easy to see
D) To give the protein molecules energy


Answer: C) Fluorescent tags make the location of the proteins easy to visualize

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?

11:30

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?


A) Osmosis
B) Active transport
C) Passive transport


Answer: C) A 25,000-dalton protein is small enough to diffuse through nuclear pores without any expenditure of energy.

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.

11:29

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.



Answer: False Cytoplasmic proteins called importins bind to large proteins containing an NLS and mediate their transport across the nuclear membrane through an active transport (energy-requiring) process.

Which of the following statements about the nuclear envelope is false?

11:29

Which of the following statements about the nuclear envelope is false?




A) Nuclear pores are made up of a group of proteins that are collectively called the nuclear pore complex.
B) The nuclear envelope is composed of two lipid bilayers.
C) The nuclear envelope is continuous with the Golgi apparatus.
D) Molecules pass into and out of the nucleus through nuclear pores.


Answer: C)This statement is false the nuclear envelope is continuous with the endoplasmic reticulum

What is the largest pool of carbon on the planet?

03:44

What is the largest pool of carbon on the planet?



A - Atmospheric carbon dioxide
B - Sediments in the deep ocean
C - Carbon dioxide dissolved in the oceans
D - Fossil fuels
E - Biomass that makes up all living matter


Answer: B - Sediments in the deep ocean
The largest pool of carbon in the world is actually in the sediments of the deep ocean which are estimated to contain about 50 times the carbon that is currently in the atmosphere. It can stay out of circulation for millions of years, unless humans intervene.

Which of the following is the best explanation for why we study the carbon cycle on a global scale and not as much in specific local ecosystems?

03:44

Which of the following is the best explanation for why we study the carbon cycle on a global scale and not as much in specific local ecosystems?



A - Carbon dioxide moves freely throughout the atmosphere and bodies of water, allowing the rapid transfer of carbon across the globe
B - Global Warming!
C - Burning fossil fuels releases carbon dioxide into the atmosphere
D - The transport of crops, animals, fossil fuels, and carbon containing materials by people gas made the carbon cycle more global in nature
E - Carbon is always readily available to all plants and animals, so it doesn't factors in at the local level at all


Answer: A - Carbon dioxide moves freely throughout the atmosphere and bodies of water, allowing the rapid transfer of carbon across the globe

Which of the following is not a way in which carbon can exit living plant material in the carbon cycle?

03:44

Which of the following is not a way in which carbon can exit living plant material in the carbon cycle?



A - Cellular respiration
B - Wildfires
C - Consumed by an animal
D - Dead plant material can be buried under sediment and eventually become fossil fuels
E - None of these are correct answers. They are all ways in which carbon can exist living plant material in the carbon cycle


Answer: E - None of these are correct answers. They are all ways in which carbon can exist living plant material in the carbon cycle

Which of the following processes takes carbon out of the short-term carbon cycle?

03:44

Which of the following processes takes carbon out of the short-term carbon cycle?



A - Decomposition of dead organic matter
B - Formation of calcium carbonate by corals
C - Photosynthesis
D - Formation of wood in trees
E - Cellular respiration


Answer: B - Formation of calcium carbonate by corals
CORAL REEFS take the most carbon out because the formation of calcium carbonate exoskeletons doesn't release carbon but solidifies it.Plants take atmospheric carbon dioxide, low in potential energy, and converts it to a high energy-containing carbohydrate using photosynthesis. Cellular respiration uses oxygen to convert organic molecules to carbon dioxide and water to provide energy to cells.

What is the primary source of carbon that can be used by plants?

03:43

What is the primary source of carbon that can be used by plants?



A - Carbon dioxide in the atmosphere
B - Dead organic material
C - Calcium carbonate
D - Inorganic carbon in the soil
E - Carbon dioxide dissolved in water


Answer: A - Carbon dioxide in the atmosphere
The primary source of carbon for plants is in the atmosphere because carbon dioxide is a gas that can move freely through the air and water.

Identify the conversion which represents nitrification.

03:43

Identify the conversion which represents nitrification.



A - Nitrite to nitrate to nitrogen to ammonia
B - Nitrate to nitrite to ammonia to nitrogen
C - Nitrogen to ammonia to nitrite to nitrate
D - Ammonia to nitrate to nitrite to nitrogen


Answer: C - Nitrogen to ammonia to nitrite to nitrate
N2 -> NH3 -> NO2- -> NO3-
NITRIFICATION doesn;t really change the amount of available nitrogen in the environment because plants and other producers can use nitrite and nitrate as sources of nitrogen, it just changes the oxidation state

Identify the statement that is NOT true about acid rain.

03:42

Identify the statement that is NOT true about acid rain.



A - Acid rain can lead to deforestation
B - Acid rain cause eutrophication of ponds and lakes
C - Acid rain can significantly lower the pH of soils and bodies of water with little buffering capacity
D - Acid rain can cause the death of sensitive aquatic animals


Answer: B - Acid rain cause eutrophication of ponds and lakes
ACID RAIN is rain that has been made more acidic by the addition of sulfur dioxide and nitrogen oxides in the atmosphere that are released when petroleum, coal, some natural gases and organic molecules (grass, tree, bush) are burned.

How is it possible to include that eutrophication of bodies of water has occurred?

03:42

How is it possible to include that eutrophication of bodies of water has occurred?



A - By testing for levels of acidity in water
B - By having a vibrant, productive aquatic ecosystems
C - By having greater species diversity in the water
D - By having massive algae blooms


Answer: D - By having massive algae blooms
EUTROPHICATION is the ecological process that occurs when excess nutrients are added to a body of water. It can occur naturally over a long period of time, allowing the organisms to get use to it, but if it is caused unnaturally by humans it can hurt the environment.

Which of the following is NOT a source of nitrogen that is available to plants?

03:42

Which of the following is NOT a source of nitrogen that is available to plants?



A - Decaying plant matter
B - Animal waste products
C - Synthetic nitrogen containing fertilizers
D - Nitrogen oxides released into the atmosphere by burning fossil fuels and organic matter


Answer: D - Nitrogen oxides released into the atmosphere by burning fossil fuels and organic matter

Put the following elements in order of abundance by weight in living organisms, starting with the most abundant, and ending with the least abundant: iron, copper, phosphorus, oxygen, and hydrogen.

03:41

Put the following elements in order of abundance by weight in living organisms, starting with the most abundant, and ending with the least abundant: iron, copper, phosphorus, oxygen, and hydrogen.



A - hydrogen, oxygen, iron, phosphorus, copper
B - oxygen, hydrogen, phosphorus, copper, iron
C - oxygen, phosphorus, hydrogen, iron, copper
D - hydrogen, oxygen, phosphorus, copper, iron
E - oxygen, hydrogen, phosphorus, iron, copper


Answer: E - oxygen, hydrogen, phosphorus, iron, copper

Which of the following is not a component of the phosphorous cycle

03:41

Which of the following is not a component of the phosphorous cycle



A - Phosphate is absorbed from the soil by plants
B - Phosphate is incorporated into sedimentary rocks
C - Atmospheric phosphate
D - Release of phosphate from rocks
E - Phosphate bound to soil


Answer: C - Atmospheric phosphate
Weathering of rocks releases phosphate into soil and then absorbed by plants making it available to consumers and detritivores who recycle it. Phosphate can be removed by harvesting the crop or becoming part of sedimentary rocks when it leaches through the soil into water, later to be put back in the soil due to the water cycle.

What is biogeochemical cycling?

03:40

What is biogeochemical cycling?



A - How an element cycles through organisms and the environment
B - The reproductive life cycle of plants that grow in rocky soil
C -The cycling of volcanic chemicals from inside Earth to outside it
D - The same span of sedimentary rocks breaking down to form soil for plants


Answer: A - How an element cycles through organisms and the environment

What is a modern human intervention in the phosphorous cycle?

03:40

What is a modern human intervention in the phosphorous cycle?



A - Replacing phosphate with magnesium
B - Planting crops that release a lot of phosphate
C - Capturing atmospheric phosphate for use as a fertilizer
D - Mining phosphate for use as a fertilizer


Answer: D - Mining phosphate for use as a fertilizer

Cloud formation is an example of condensation because.

03:39

Cloud formation is an example of condensation because.



A - Liquid water falls as rain, sleet, snow, or ice
B - Water is absorbed into the ground
C - Water vapor condenses around particles in the atmosphere
D - Liquid water is converted into is gaseous state


Answer: C - Water vapor condenses around particles in the atmosphere

Transpiration is the process that occurs when.

03:39

Transpiration is the process that occurs when.



A - Water vapor is converted to a liquid state
B - Water is absorbed into the ground
C - Plants lose water through the leaves
D - Humans absorb water by breathing


Answer: C - Plants lose water through the leaves
Eventually, most surface water will be reabsorbed as groundwater, evaporate from the surface or from the ocean.

What are the three main parts of the water cycle?

03:39

What are the three main parts of the water cycle?



A - Evaporation, condensation, and precipitation
B - Absorption, infiltration, and transpiration
C - Precipitation, infiltration, and condensation
D - Evaporation, condensation, and cloud formation


Answer: A - Evaporation, condensation, and precipitation


CONDENSATION is the process by which water vapor is changed back into liquid state. PRECIPITATION is when water falls from the atmosphere in the form of rain, sleet, snow, hail, or freezing rain. Clouds are required because raindrops are the drops of the cloud that have condensed enough water to begin falling.

Steam is an example of which part of the water cycle?

03:39

Steam is an example of which part of the water cycle?



A - Ground absorption
B - Condensation
C - Precipitation
D - Evaporation
D - Evaporation


Answer: EVAPORATION is the process by which water is converted from its liquid state to the gaseous state.

Three babies were recently mixed up in a hospital. Based on the data in the table above, the couple with blood types B and O are the actual parents of the child with blood type

03:34
Parent Blood Types A and B A and A B and O
Child Blood Type O B AB

Three babies were recently mixed up in a hospital. Based on the data in the table above, the couple with blood types B and O are the actual parents of the child with blood type



A. O
B. B
C. AB
D. none of these babies could be the child of the couple with blood types B and O


Answer: B

In rabbits there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what proportion of the long-eared offspring will be homozygous for that trait?

03:32

In rabbits there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what proportion of the long-eared offspring will be homozygous for that trait?



A. 1/8
B. 1/4
C. 1/3
D. 1/2


Answer: C

In rabbits, there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what is the probability that their first offspring will be gray with long ears?

03:31

In rabbits, there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what is the probability that their first offspring will be gray with long ears?



A. 1/16
B. 3/16
C. 1/8
D. 3/8
E. 1/2


Answer: D

In watermelons, the gene for green color is dominant over its allele for striped color. At another gene locus, the gene for short shape is dominant over its allele for long shape. These two allele pairs assort independently. If a plant with long, striped fruit is crossed with a plant that is heterozygous for both of these traits, what percentage of the offspring do you expect will be short and green?

03:31

In watermelons, the gene for green color is dominant over its allele for striped color. At another gene locus, the gene for short shape is dominant over its allele for long shape. These two allele pairs assort independently. If a plant with long, striped fruit is crossed with a plant that is heterozygous for both of these traits, what percentage of the offspring do you expect will be short and green? ( Enter the number only without the percent sign. For example, enter 100% as 100 and enter 12.5% as 12.5 )



Answer: 25

In humans, sickle-cell disease is caused by a single defective allele. If 2 people without sickle-cell disease have a daughter who has this disease, what is the probability that their next child will be a boy with sickle-cell disease?

03:28

In humans, sickle-cell disease is caused by a single defective allele. If 2 people without sickle-cell disease have a daughter who has this disease, what is the probability that their next child will be a boy with sickle-cell disease?



A. 1/16
B. 1/8
C. 1/4
D. 3/8
E. 1/2


Answer: A

In mice, the allele for black fur is dominant to the allele for brown fur. If a male heterozygous black mouse is crossed with a female brown mouse, what percentage of the F1 offspring do you predict will be homozygous?

03:28

In mice, the allele for black fur is dominant to the allele for brown fur. If a male heterozygous black mouse is crossed with a female brown mouse, what percentage of the F1 offspring do you predict will be homozygous? ( Enter the number only without the percent sign. For example, enter 100% as 100 and enter 12.5% as 12.5 )



Answer: 50

A scientist has a pea plant that produces yellow-seeds. Since yellow is dominant to green, she wants to determine if the plant is homozygous or heterozygous. In order to be certain that she will get conclusive results from a single cross, she could cross it with: Check all that apply.

03:27

A scientist has a pea plant that produces yellow-seeds. Since yellow is dominant to green, she wants to determine if the plant is homozygous or heterozygous. In order to be certain that she will get conclusive results from a single cross, she could cross it with: Check all that apply.



__X__ a green-seeded pea plant
_____ a yellow-seeded pea plant
_____ a pea plant that produces both yellow and green seeds
__X__ itself

Before Mendel's experiments with pea plants, which ideas formed the basis for most thinking about heredity? Check all that apply.

03:27

Before Mendel's experiments with pea plants, which ideas formed the basis for most thinking about heredity? Check all that apply.



_____ species gradually change over time
__X__ the traits of both parents are blended together in their offspring
__X__ heredity occurs within species
_____ some traits are dominant and some are recessive
__X__ traits are transmitted directly from parents to offspring


Answer: 

Mendel performed reciprocal crosses in which he used pollen from a white-flowered plant to fertilize a purple-flowered plant and pollen from a purple-flowered plant to fertilize a white-flowered plant. What did these reciprocal crosses demonstrate?

03:26

Mendel performed reciprocal crosses in which he used pollen from a white-flowered plant to fertilize a purple-flowered plant and pollen from a purple-flowered plant to fertilize a white-flowered plant. What did these reciprocal crosses demonstrate?



A. The female gamete made a larger genetic contribution to the offspring than the male gamete.
B. Each parent made an equal genetic contribution to the offspring.
C. Flower color is a sex-linked trait.
D. The traits of flower color and sex assort independently.
E. The male gamete made a larger genetic contribution to the offspring than the female gamete.


Answer: B

Achondroplasia is a common form of dwarfism caused by an autosomal dominant mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. Two copies of the mutant gene are invariably fatal before or shortly after birth. If a person with achondroplasia marries a person of normal height, what is the probability that both their first child and second child will have achondroplasia?

03:26

Achondroplasia is a common form of dwarfism caused by an autosomal dominant mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. Two copies of the mutant gene are invariably fatal before or shortly after birth. If a person with achondroplasia marries a person of normal height, what is the probability that both their first child and second child will have achondroplasia?



A. 1/8
B. 1/4
C. 1/2
D. 1


Answer: B

A Punnett square is generally used to

02:32

A Punnett square is generally used to



A. determine the genotype of each parent from its phenotype.
B. determine the phenotype of each parent from its genotype.
C. predict the genotypic ratio among the offspring.
D. predict the number of offspring that will exhibit each genotype.


Answer: C

Let R = red pigment and r = no pigment. In carnations, RR offspring make a lot of red pigment, rr offspring make no pigment and Rr offspring make a small amount of red pigment, thus appearing pink. Pink carnations are therefore an example of

01:52

Let R = red pigment and r = no pigment. In carnations, RR offspring make a lot of red pigment, rr offspring make no pigment and Rr offspring make a small amount of red pigment, thus appearing pink. Pink carnations are therefore an example of



A. codominance.
B. incomplete dominance.
C. epistasis.
D. pleiotropy.


Answer: B

Let Y = yellow and y = green, and R = round and r = wrinkled. You cross YYRR peas with yyrr peas. All of the F1 individuals are yellow and round with a genotype of YyRr. You then perform an F2 cross and get the expected 9:3:3:1 phenotypic ratio. What proportion of the F2 plants are expected to be heterozygous for both traits?

01:01

Let Y = yellow and y = green, and R = round and r = wrinkled. You cross YYRR peas with yyrr peas. All of the F1 individuals are yellow and round with a genotype of YyRr. You then perform an F2 cross and get the expected 9:3:3:1 phenotypic ratio. What proportion of the F2 plants are expected to be heterozygous for both traits?



A. 1/16
B. 1/4
C. 1/2
D. 9/16


Answer: B

In white tigers, the absence of fur pigmentation is caused by a recessive allele. This allele also causes the tigers to be cross-eyed. If two tigers heterozygous for this allele mate, what do you expect to see among the offspring?

00:45

In white tigers, the absence of fur pigmentation is caused by a recessive allele. This allele also causes the tigers to be cross-eyed. If two tigers heterozygous for this allele mate, what do you expect to see among the offspring?



A. 1/4 will be both white and cross-eyed.
B. 1/4 will be white and 1/4 will be cross-eyed, but not necessarily the same 1/4 due to independent assortment.
C. 1/16 will be white and 1/16 will be cross-eyed, but not necessarily the same 1/16 due to independent assortment.
D. 1/16 will be both white and cross-eyed.


Answer: A

A person who has lost a large amount of blood but is still alive is found in a wrecked automobile under a highway bridge. Several people are helping the paramedics load the victim into the ambulance. After the ambulance has departed for the hospital, you overhear the following conversation from the persons who helped the paramedics. " I am certain when that guys gets to the hospital, they will transfuse him with any blood that they have in the blood bank since he has lost so much blood" the other person says " Yeah i bet you're right"! having has a biology course, you know which blood could be safely given to anyone. Select it below

00:42

A person who has lost a large amount of blood but is still alive is found in a wrecked automobile under a highway bridge. Several people are helping the paramedics load the victim into the ambulance. After the ambulance has departed for the hospital, you overhear the following conversation from the persons who helped the paramedics. " I am certain when that guys gets to the hospital, they will transfuse him with any blood that they have in the blood bank since he has lost so much blood" the other person says " Yeah i bet you're right"! having has a biology course, you know which blood could be safely given to anyone. Select it below



a. A
b. B
c. AB
d. O


Answer: d. O

Irene knows her body type is A, but William does not know his blood type. However, William knows that his mother and father both had blood type B. Irene and William's first child is a boy with type O blood. Based on this info, William's blood type could be

00:42

Irene knows her body type is A, but William does not know his blood type. However, William knows that his mother and father both had blood type B. Irene and William's first child is a boy with type O blood. Based on this info, William's blood type could be



a. B only
b. either B or O
c. O only
d. either AB or O
e. A only


Answer: b. either B or O

An extensive study was conducted on identical twins who were seperated at birth. Among other things, the study showed that the individual from each pair who received better nutrition during childhood tended to score higher on standardized intelligence tests. this can best be described as an example of how

00:42

An extensive study was conducted on identical twins who were seperated at birth. Among other things, the study showed that the individual from each pair who received better nutrition during childhood tended to score higher on standardized intelligence tests. this can best be described as an example of how



a. mutation alter genotype
b. environment alters phenotype
c. environment alters genotype
d. mutation alters genotype
e. pleiotropic genes affect more than one trait


Answer: b. environment alters phenotype

Height is a trait that shows continuous variation in humans. In pea plants, onn the other hand, the tall allele is dominant over the short allele and there are no intermediate heights. What is the best explanation for this difference

00:41

Height is a trait that shows continuous variation in humans. In pea plants, onn the other hand, the tall allele is dominant over the short allele and there are no intermediate heights. What is the best explanation for this difference



a. the alleles that control height in pea plants are epistatic
b. the alleles that control height in pea plants are pleiotropic
c. the alleles that control height in humans are pleiotropic
d. height is a polygenic trait in humans
e. height is a polygenic trait in pea plants


Answer: d. height is a polygenic trait in humans

Sometimes when Mendel crossed two purple-flowered pea plant with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants). These results are consistent with which of the following sets of parents

00:41

Sometimes when Mendel crossed two purple-flowered pea plant with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants). These results are consistent with which of the following sets of parents



a. homozygous purple pea plant and homozygous white pea plant
b. homozygous purple pea plant and heterozygous white pea plant
c. heterozygous purple pea plants and homozygous white pea plants
d. heterozygous purple pea plants and homozygous purple pea plant
e. heterozygous purple pea plant and heterozygous purple pea plant


Answer: e. heterozygous purple pea plant and heterozygous purple pea plant

When Mendel crossed purple-flowered pea plants with white flowered pea plants, he never got offspring with flowers that had an intermediate color. This was counter to the theory of

00:41

When Mendel crossed purple-flowered pea plants with white flowered pea plants, he never got offspring with flowers that had an intermediate color. This was counter to the theory of



a. independent assortment
b. blending inheritance
c. direct transmission traits
d. segregation of alleles
e. continuous variation of traits


Answer: b. blending inheritance

ABO blood group determination is an example of

00:40

ABO blood group determination is an example of



a. epistasis
b. incomplete dominance
c. polygenic inheritance
d. multiple alleles
e. pleiotropy


Answer: d. multiple alleles

The independent assortment of allele pairs is due to

00:39

The independent assortment of allele pairs is due to



a. the independent segregation of homologous chromosome pairs during anaphase II
b. the random combination of gametes during fertilization
c. the independent segregation of sister chromatids pairs during anaphase I
d. the independent segregation of non-sister chromatids pairs during anaphase II
e. the independent segregation of homologous chromosome pairs during anaphase I


Answer: e. the independent segregation of homologous chromosome pairs during anaphase I

Mendel's principle of independent assortment states that different pairs of

00:39

Mendel's principle of independent assortment states that different pairs of



a. non homologous chromosomes segregate independently of each other
b. sister chromatids segregate independently of each other
c. non-sister chromatids segregate independently of each other
d. alleles segregate independently of each other
e. gametes segregate independently of each other


Answer: d. alleles segregate independently of each other

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. Of the 16 possible gamete combinations in the dihybrid cross between 2 double heterozygotes, how many would produce the phenotype white, tall?

23:53

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. Of the 16 possible gamete combinations in the dihybrid cross between 2 double heterozygotes, how many would produce the phenotype white, tall?



a.none
b. 1
c. 3
d. 9
e. 16


Answer: c. 3

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. What are the genotypes of the gametes that could be produced by a plant that is heterozygous for both traits

23:51

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. What are the genotypes of the gametes that could be produced by a plant that is heterozygous for both traits



a. PpTt only
b. both Pp and Tt
c. P,p,T, and t
d. PT, Pt, pT, and pt
e. Tt, TT, tt, Pp,PP, and pp


Answer: d. PT, Pt, pT, and pt

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. If the upper case letters represent the dominant alleles, what is the phenotype of a plant with the genotype PpTt?

23:51

Let P=purple flowers and p=white, and T=tall plants and t=dwarf. If the upper case letters represent the dominant alleles, what is the phenotype of a plant with the genotype PpTt?



a. purple flowers, tall
b. purple flowers, dwarf
c. white flowers, tall
d. white flowers, dwarf
e. pale purple flowers, intermediate height


Answer: a. purple flowers, tall

Based on his monohydrid crosses, Mendel's proposed which of the following

23:50

Based on his monohydrid crosses, Mendel's proposed which of the following



a. alternative forms of a trait are encoded by alternative alleles
b. the 2 alleles for a given trait separate when gametes form
c. each allele has an equal probability of being passed on to the gametes
d. allele pairs segregate independently of each other
e. diploid individuals have 2 alleles for each trait


Answer: a,b,c,e

Mendel's understanding of the inheritance of traits in peas, expressed in modern language, included

23:46

Mendel's understanding of the inheritance of traits in peas, expressed in modern language, included



a. parents transmit information encoded in genes
b. each individual contains two genes for each trait
c. not all genes are identical; alternative forms (alleles) exist
d. each of the alleles present in an individual is discrete
e. if a given allele is present, its effects will be seen in the individual


Answer: a,b,c,d

In mendel's experiments on seed color in pea plants, when a dominant yellow seed-bearing plant was crossed with a recessive green seed-bearing plant, what was the approximate phenotypic ratio among the F2 generation

23:43

In mendel's experiments on seed color in pea plants, when a dominant yellow seed-bearing plant was crossed with a recessive green seed-bearing plant, what was the approximate phenotypic ratio among the F2 generation



a. 1 yellow: 3 green
b. 1 yellow: 1 green
c. 3 yellow: 1 green
d. all yellow
e. 9:3:3:1


Answer: c. 3 yellow: 1 green

Mendel chose the garden pea for his work on inheritance for which of the following reason

23:43

Mendel chose the garden pea for his work on inheritance for which of the following reason



a. some traits in pea plants are controlled by one dominant allele and one recessive allele
b. earlier investigators had shown segregation among the offspring
c. a large number of true breeding varieties were available
d. the generation time was short; many offspring can be grown easily
e. he could choose to self or cross pollinate


Answer: b,c,d,e

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas. When he crossed two true-breeding varieties, he found all of the following

23:43

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas. When he crossed two true-breeding varieties, he found all of the following



a. All the F1 offspring had the dominant trait
b. If both parents have the same trait, then all of their offspring will also have that trait
c. some F2 offspring had the dominant trait and some had the recessive trait
d. among the F2 offspring more had the dominant trait and fewer had the recessive trait


Answer: a,c,d

Mendel demonstrated which of the following about inherited traits?

23:43

Mendel demonstrated which of the following about inherited traits?



a. traits can be hidden in some generations, but subsequently reappear unchanged in future generations
b. traits segregate among offspring of a cross
c. certain traits are more likely to appear than their alternatives
d. some traits show blending inheritance
e. parents that both have the same trait can have offspring with an alternative trait


Answer: a, b, c,e
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