Biology Final

Which of the following is a benefit of sexual reproduction? 

It increases genetic variation and variation of phenotypes within a population.

The process of meiosis begins with:

one diploid cell and ends with 4 haploid cells that are the gametes used in sexual reproduction in the organism

Genetic traits of seeds are noted as follows:  \n W = wrinkled, w = smooth  \n Y = yellow, y = white  

If we know that these genes are on different chromosomes, What % of the offspring will be wrinkled and smooth if you cross two heterozygous individuals?

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0%

Genetic traits of seeds are noted as follows: \n W = wrinkled, w = smooth  \n Y = yellow, y = white  

If we know that these genes are on different chromosomes. What are the phenotype ratios for texture (wrinkled/smooth) if you cross a heterozygous parent with a homozygous recessive parent.

1 wrinkled:1 smooth

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Which of the following could be coded by a tumor-supressor gene?

A protein that helps prevent progression through cell cycle

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Genes encode proteins and proteins dictate cell function.  Therefore, the thousands of genes expressed in a particular cell determine what the cell can do.  Moreover, each step in the flow of information from DNA to RNA to protein provides the cell with a potential control point for self-regulating its functions by adjusting the amount and type of proteins it manufactures.

Choose the best description of activators and repressors of gene expression.

Activators are, in most cases proteins that bind to the promoter sequence and the enhancer sequence of DNA upstream of the gene and stimulate the binding of RNA polymerase to the DNA at the gene

The diagram below represents a portion of a molecule found in cells of the human body.

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Sequences represented by the letters in this molecule enable human cells to 

synthesize enzymes from organic molecules

Genetic traits of seeds are noted as follows: \n L = long, l = short \n W = wrinkled, w = smooth \n Y = yellow, y = white \n R = ribbed, r = grooved \n \n Which of the following is the genotype for a short, wrinkled, yellow, grooved seed?

llWwYYrr

Sometimes, a person is born with one or more extra chromosomes in each cell. This usually \n results in abnormalities because the affected person has

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an overproduction of proteins from the increased number of genes in each cell compared to a person without the extra chromosome

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For a human zygote to become an embryo, it must undergo

mitotic divisions

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Which statement concerning a pair of alleles for a gene controlling a single characteristic in humans is true? 

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One allele comes from the mother and one allele comes from the father.

When a paramecium, a single-celled organism, is living under stressful conditions, it sometimes \n switches from asexual to sexual reproduction. The main advantage when this switch occurs is that the paramecium is most likely to

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increase variation among its offspring

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Choose the statement that best describes the purpose of the M phase of the cell cycle.

organize and separate replicated chromosomes into two nuclei

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Some plants increase in height due to changes in specialized regions of cells in the tips of their \n branches. The processes that result in these changes include

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mitosis, cell growth, and differentiation

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What is the function of apoptosis?

to weed out cells that grow uncontrollably

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A technique used to alter cells is represented in the diagram below.

The genetic material contained in the nucleus of each of the new cells is most likely

identical to that in the original body cell

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Cells in the human body move through the cell cycle at varying rates. To repair tissues and to grow it is necessary for cells to go through the cell cycle successfully. Which choice best describes the cell cycle? 

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Cells grow and develop during interphase.

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An extra finger in humans is rare but is due to a dominant gene. When one parent is normal and the other parent has an extra finger but is heterozygous for the trait, what is the probability that the first child will have five (the normal number) fingers? 

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50%

Genetic traits of seeds are noted as follows: \n W = wrinkled, w = smooth  \n Y = yellow, y = white  

What are the possible gametes of parent 1 with the genotype WwYy?

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WY, Wy, wY, wy

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Compared to a normal somatic cell, a normal gamete cell contains

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half the number of chromosomes

Hair follicle cells are long-lived cells in the hair follicle; they are present in the skin and produce hair throughout a person’s lifetime. They are “quiescent,” meaning they are normally inactive, but they quickly activate during a new hair cycle, which is when new hair growth occurs. The quiescence of hair follicle cells is regulated by many factors. In certain cases they fail to activate, which is what causes hair loss. Researchers at UCLA have found that when lactate production was decreased the study mice showed a loss of hair. The opposite was found when they increased the lactate produced during basic metabolism in these cells. This shows potential as a treatment to increasing hair growth in those with alopecia and hair loss. 

What multipotent stem cells would this drug be acting upon? 

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skin precursor cell

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Researchers recently discovered that when hammerhead sharks were moved to shallower water, resulting in exposure to increased light intensity, their backs turned a deep brownish black. Which statement best supports this observation?

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Genes are inherited, but their expression can be modified by interactions with the environment.

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Normal human eggs have: 

22 autosomes and an X chromosome.

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Nicotine is only one of the many toxic chemicals inhaled while smoking. What effect can such toxic chemicals have on the body?

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They can cause uncontrolled cell division.

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An example of a genotype is:

TtHH

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Potatoes were the main crop in Ireland in the 1800s. Almost the entire population of Ireland was dependent on a single variety of potato, the “lumper.” These potatoes were reproduced by a method of asexual reproduction known as vegetative propagation. In the middle of the 1800s, a disease caused by a fungus killed almost the entire lumper crop within two years. As a result, millions of people in Ireland died of starvation. The most likely reason the potato disease was able to destroy the potato crop in such a short time is that the

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potato population lacked variations

The diagram below represents a form of cellular reproduction.

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the same number of genes and the same traits

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An example of alleles is: 

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T and t

During the cell cycle, there are various checkpoints that are necessary in regulating the speed at which cells are duplicated as well as identifying cells for apoptosis (programmed cell death). Which of the following correctly identifies the purpose of cell cycle checkpoint. 

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D

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A pedigree chart shows: 

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The pattern of inheritance of a specific gene.

Female mosquitoes spread diseases when they bite humans to obtain blood. It is only the females that do the biting. Research is being conducted to alter the DNA of male mosquitoes. These altered males could then mate with normal female mosquitoes. All of the resulting female offspring would have wing defects that prevent them from flying.

One assumption from this research is that the

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female offspring would be unable to bite humans, since they cannot fly

Human genetic material is represented in the diagram below.

The region labeled A is made up of a section of

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DNA that may direct protein synthesis

In transcription _____  __is read to make a complimentary mRNA molecule by attaching free floating RNA nucleotides together. mRNA is translated at the ribosome to produce a__ _________

DNA, protein

Car manufacturers have begun to explore the use of biofuels, such as biodiesel, ethanol, and cooking oils made from plant material. The desired outcome of using these biofuels would be

a decrease in the use of fossil fuels

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Bacteria and humans are similar in that they both

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contain genetic material in the form of nucleic acids

Female mosquitoes spread diseases when they bite humans to obtain blood. It is only the females that do the biting. Research is being conducted to alter the DNA of male mosquitoes. These altered males could then mate with normal female mosquitoes. All of the resulting female offspring would have wing defects that prevent them from flying.

The method used to alter the male mosquitoes is an example of an application of

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genetic transformation

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The product(s) of translation include: 

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a polypeptide (amino acid sequence)

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A bacterial cell begins to produce a new type of protein. This is most likely due to an alteration of the

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sequence of bases in a section of a chromosome

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Which sequence best represents increasing complexity?

organelles → cells → tissues → organs

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A normal sequence of DNA bases in a gene segment from a human skin cell is 5' TACTCGGCATTG 3' what would be the mRNA transcript from this gene segment? 

3' _ _ _ _ _ _ _ _ _ _ _ _ 5'

AUGAGCCGUAAC

What might be the result of a mutation of DNA in which a sequence is altered from

5' TAC GGA TGG ACA GCC ACT 3' to 5' TAC  GGA TAG ACA GCC ACT 3'

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This is a missense point mutation that would cause one amino acid to be different. This may cause a change in shape and function depending on where in the sequence the changed amino acid is found.

If  the DNA analysis of a gene shows 30% adenine bases, what would be the percentage of thymine? 

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30%, 20%, 20%, 0%

The diagram below represents a technique used in some molecular biology laboratories.

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Which phrase best describes a possible result of this process?

the production of a human protein by the bacterial cell

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A normal sequence of DNA bases in a single human skin cell is CATGGC. If this sequence replicates in this cell and becomes GATGGC, this alteration will most likely be passed to

every cell that develops from this parent cell

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The diagram represents a process used to modify bacterial cells.

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In the diagram, arrows labeled X and Y represent the use of

enzymes

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The instructions for the genetic traits of an organism are directly determined by the

sequence of bases in DNA molecules

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A tomato gene, known as the SIKLUH gene, has recently been discovered. The gene leads to the \n production of larger tomatoes. The gene affects fruit size by increasing cell layers and promoting \n extra cell divisions. In order to produce large fruit in other commercial plant species, scientists \n might

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insert the gene into other types of plants

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Information in segments of human DNA can be expressed by a bacterial cell as a result of

genetic engineering

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C

The diagram below represents a microscopic structure observed during mitosis.

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a gene

**Meselson** and **Stahl** tested the hypothesis of **DNA replication**. They cultured bacteria in a 15N medium. 15N is a heavy isotope of nitrogen so the **DNA**synthesized is of heavy density. They then shifted the bacteria to a 14N medium,**DNA** was isolated at different times corresponding to **replication** cycles 0, 1, and 2. DNA was isolated at different times corresponding to replication cycles 0, 1, and 2. After one replication cycle, the DNA was all of intermediate density. After two replication cycles, two bands of DNA were seen, one of intermediate density and one of light density. (from http://www.phschool.com/science/biology_place/biocoach/dnarep/experiment.html#animation) (Links to an external site.)

Which of the following hypotheses about DNA replication are supported by the data given. 

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Semi-conservative replication. In this model, the two strands of DNA unwind from each other, and each acts as a template for synthesis of a new, complementary strand. This results in two DNA molecules with one original strand and one new strand.

Mutations cause many disorders in humans. Cystic fibrosis (CF) is a disorder that can be passed on from generation to generation. Skin cancer is a disorder that sometimes originates in skin cells as a result of overexposure to the Sun.

Which statement best explains the formation of the mutations that cause both cystic fibrosis and skin cancer?

Both of these mutations involve a change in the nucleotide sequence of genes.

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The following table is a representative sample of Erwin Chargaff's 1952 data, listing the base composition of DNA from various organisms. From this data it can be determined that...

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DNA from any cell of any organisms should have a 1:1 ratio of pyrimidine and purine bases

A news release about production of farm-raised salmon contains the following information: \n -The program is mating targeted fish to concentrate key traits in Atlantic salmon stocks. \n -The three-year process includes spawning, tagging, and choice of parent fish. \n -The fish are weighed, measured, and monitored to identify those with the best growth rates. \n -The project examines the performance of fish to determine which fish to use to produce the next generation. \n \n These statements indicate that the producers are attempting to improve salmon through the use of

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selective breeding

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Free amino acids in the cytoplasm of our cells are transported and used during translation. What is ultimately the original source of free amino acids in the cytoplasm? 

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Food that contains proteins.