1.
Which transfers information from the NUCLEUS of a cell to the CYTOPLASM
Correct Answer
C. MRNA
Explanation
mRNA, or messenger RNA, transfers information from the nucleus of a cell to the cytoplasm. This process is known as transcription, where DNA is used as a template to create mRNA molecules. mRNA carries the genetic code from the DNA to the ribosomes in the cytoplasm, where it is used as a template for protein synthesis. This allows the genetic information stored in the nucleus to be translated into functional proteins in the cytoplasm.
2.
Which of the following is NOT a difference between RNA and DNA
Correct Answer
B. RNA has five bases, but DNA only four
Explanation
The given answer is correct because RNA has four bases (adenine, guanine, cytosine, and uracil) while DNA has four bases (adenine, guanine, cytosine, and thymine). Therefore, RNA has five bases, including uracil, which is not found in DNA.
3.
Which of the following most directly transfers information from a chain of nucleotides to a chain of amino acids.
Correct Answer
C. TRNA
Explanation
tRNA (transfer RNA) directly transfers information from a chain of nucleotides to a chain of amino acids during protein synthesis. It carries amino acids to the ribosome, where the genetic information stored in mRNA (messenger RNA) is used to assemble the correct sequence of amino acids. This process, known as translation, is essential for the synthesis of proteins in cells. DNA (deoxyribonucleic acid) carries the genetic information, but it is transcribed into mRNA before being translated into amino acids by tRNA. rRNA (ribosomal RNA) is a component of the ribosome, where protein synthesis occurs, but it does not directly transfer information from nucleotides to amino acids.
4.
Lymphomas and leukemias affect which type of cells
Correct Answer
B. Blood
Explanation
Lymphomas and leukemias are types of cancers that affect the blood cells. Lymphomas specifically target the lymphatic system, which is a part of the immune system, while leukemias affect the bone marrow and result in abnormal production of white blood cells. Both lymphomas and leukemias primarily involve the blood cells and can have significant impacts on the overall functioning of the blood and immune system. Therefore, the correct answer is blood.
5.
The central dogma of molecular biology states that ______ is transcribed into ______ which is translated into _______.
Correct Answer
D. DNA/RNA/protein
Explanation
The central dogma of molecular biology states that genetic information stored in DNA is transcribed into RNA through the process of transcription, and then this RNA is translated into protein through the process of translation. This is a fundamental principle in biology that explains the flow of genetic information and the synthesis of proteins in living organisms.
6.
Cancer may be caused by ________.
Correct Answer
D. All of these
Explanation
All of these options can cause cancer. Carcinogens are substances that can directly damage DNA and lead to the development of cancer. Viruses, such as human papillomavirus (HPV) and hepatitis B and C, can also cause certain types of cancer by infecting cells and disrupting their normal functions. Additionally, certain substances found in food, such as aflatoxins and nitrites, have been linked to an increased risk of cancer. Therefore, all three options can contribute to the development of cancer.
7.
A single gene specifically contains information for
Correct Answer
A. Synthesis of a single protein
Explanation
A single gene specifically contains information for the synthesis of a single protein. This means that the gene carries the instructions for the production of a specific protein molecule. Proteins are essential for various biological processes and functions in the body, such as enzyme activity, structural support, and cell signaling. Each gene is responsible for coding the sequence of amino acids that make up a particular protein, and this information is then used by the cell's machinery to produce that specific protein. Therefore, the correct answer is that a single gene contains information for the synthesis of a single protein.
8.
If a codon were read two bases at a time instead of three bases at a time, how many different possible amino acids could be specified?
Correct Answer
A. 16
Explanation
If a codon were read two bases at a time instead of three bases at a time, there would be a total of 16 different possible combinations. This is because each base can have 4 different options (A, T, G, C), and if two bases are read together, there would be 4 possibilities for each base, resulting in 4x4=16 possible combinations. Each combination would correspond to a different amino acid, so there would be 16 different possible amino acids that could be specified in this scenario.
9.
Which is true of mutations
Correct Answer
C. Some are visible only under certain conditions
Explanation
Mutations can occur in different forms, including changes in a single nucleotide or larger alterations in the structure of a chromosome. Therefore, not all mutations involve whole chromosomes. Additionally, mutations can occur in both somatic cells and gametes, so they are not limited to gametes only. Some mutations may only be visible under certain conditions, such as specific environmental factors or genetic backgrounds. Finally, most mutations are not beneficial and can have neutral or harmful effects on an organism.
10.
One of the major direct benefits of mutations for a population is:
Correct Answer
B. Introduction of new genetic material
Explanation
Mutations are changes in the DNA sequence that can introduce new genetic material into a population. This new genetic material can lead to the development of new traits or variations, which can be beneficial for the population's survival and adaptation to changing environments. Therefore, the introduction of new genetic material through mutations is a major direct benefit for a population.
11.
Which is true of mutations
Correct Answer
B. Heritable changes in the sequence of nucleotides in DNA
Explanation
Mutations are heritable changes in the sequence of nucleotides in DNA. This means that there is a permanent alteration in the DNA sequence that can be passed on to future generations. These changes can occur due to various factors such as errors during DNA replication, exposure to mutagens, or spontaneous changes. Mutations can lead to observable changes in an organism's characteristics or traits, which can have both positive and negative effects on the organism's survival and evolution.
12.
Which is an example of a chromosomal mutation
Correct Answer
D. All of these
Explanation
All of the given options are examples of chromosomal mutations. The replacement of the sequence UGU with UGC is a substitution mutation, where one nucleotide is replaced by another. Substitution of a single base in DNA is also a type of substitution mutation. A segment of DNA being lost is a deletion mutation, where a portion of the DNA sequence is lost. Therefore, all of these options demonstrate different types of chromosomal mutations.
13.
Which is true of mutations
Correct Answer
D. All of these
Explanation
Mutations can often result in the production of abnormal proteins, which can lead to various disorders or diseases. However, not all mutations necessarily change the sequence of amino acids coded for by the mutated gene. Some mutations can occur in non-coding regions of the gene or can be silent mutations that do not affect the resulting protein. Additionally, while some mutations can be harmful and have negative effects on the organism, not all mutations are necessarily detrimental. Some mutations can be neutral or even beneficial, providing advantages in certain environments or contributing to genetic diversity. Therefore, all of the given statements are true about mutations.
14.
Which best applies to the thousands of genes found in your DNA
Correct Answer
D. Some are expressed constantly and others infrequently
Explanation
The answer suggests that not all genes in your DNA are expressed at the same frequency. Some genes are expressed constantly, meaning they are active and producing proteins throughout various life stages. On the other hand, other genes are expressed infrequently, indicating that they are only active and producing proteins under specific circumstances or conditions. This highlights the dynamic nature of gene expression and the complex regulation of gene activity in the human body.
15.
About 85% of human cancers result from some type of
Correct Answer
B. Genetic Disorder
Explanation
The given question asks for the cause of about 85% of human cancers. The correct answer is "Genetic Disorder." This means that the majority of human cancers are caused by abnormalities or mutations in genes that control cell growth and division. These genetic disorders can be inherited from parents or acquired throughout a person's lifetime due to various factors such as exposure to certain chemicals or radiation.
16.
About 85% of all human tumors are
Correct Answer
B. Carcinomas
Explanation
Carcinomas are the correct answer because they account for about 85% of all human tumors. Carcinomas are a type of cancer that starts in the epithelial cells, which are the cells that line the internal and external surfaces of the body. They can occur in various organs such as the lungs, breast, colon, and skin. Carcinomas are typically characterized by the formation of solid tumors and can metastasize to other parts of the body. This high prevalence of carcinomas among human tumors makes them the most common type of cancer.
17.
Genetic disorders may be
Correct Answer
D. All of these
Explanation
Genetic disorders can be inherited as recessive alleles, meaning that both parents must carry the gene for the disorder in order for it to be passed on to their children. They can also be X-linked traits, which means that the gene responsible for the disorder is located on the X chromosome. Lastly, some genetic disorders may be passed more frequently from mothers to sons due to the inheritance patterns of certain genes. Therefore, all of these options are possible explanations for the occurrence of genetic disorders.
18.
Which best applies to stem cells
Correct Answer
B. They have the potential to develop into any number of cell types
Explanation
Stem cells have the potential to develop into any number of cell types. This means that they are undifferentiated cells that can differentiate into specialized cells such as muscle cells, nerve cells, or blood cells. This ability makes stem cells valuable in regenerative medicine and research, as they can potentially be used to replace or repair damaged or diseased tissues and organs. Stem cells are not a cure for all diseases, and their potential varies depending on the source of the stem cells, but their ability to differentiate into different cell types is a fundamental characteristic of stem cells.
19.
Which is true of ribosomes
Correct Answer
D. All of these
Explanation
Ribosomes are cellular structures responsible for protein synthesis. They consist of large and small subunits, which come together to form a functional ribosome. These subunits are made up of ribosomal RNA (rRNA) molecules and proteins. Therefore, all the given statements are true of ribosomes.
20.
Uncontrolled cell division is
Correct Answer
C. Cancer
Explanation
Cancer is the correct answer because uncontrolled cell division is a characteristic feature of cancer. Cancer occurs when normal cells undergo genetic mutations that cause them to divide and grow uncontrollably, forming a mass of abnormal cells called a tumor. This unregulated cell division can lead to the spread of cancer cells to other parts of the body, causing further complications and potentially leading to death if left untreated. Therefore, cancer is the most appropriate term to describe uncontrolled cell division.
21.
Spontaneous mutations occur as a result of
Correct Answer
C. Instabilities in DNA
Explanation
Spontaneous mutations occur as a result of instabilities in DNA. These instabilities can be caused by various factors such as errors during DNA replication, chemical reactions within the cell, or the natural decay of DNA over time. These instabilities can lead to changes in the DNA sequence, resulting in a mutation. Damage to DNA by an outside agent, incomplete gene expression, and alteration of DNA can also cause mutations, but the question specifically asks for the cause of spontaneous mutations, which is instabilities in DNA.
22.
Three codons that do not specify a match with any anticodons are
Correct Answer
A. Stop codons
Explanation
Stop codons are a group of three nucleotide sequences (UAA, UAG, and UGA) that do not have corresponding anticodons. They signal the termination of protein synthesis during translation. When a stop codon is encountered by the ribosome, it signals the release of the newly synthesized protein and the termination of translation. This is why stop codons do not have any matching anticodons, as they are not involved in the incorporation of amino acids into the growing polypeptide chain.
23.
A sequence of three RNA nucleotides can function as a
Correct Answer
D. Both b & c
Explanation
A sequence of three RNA nucleotides can function as a codon, which is a specific sequence of nucleotides that codes for a particular amino acid in protein synthesis. Additionally, this sequence can also function as an anticodon, which is found on transfer RNA (tRNA) and pairs with the complementary codon on messenger RNA (mRNA) during translation. Therefore, the correct answer is "Both b & c" as a sequence of three RNA nucleotides can serve as both a codon and an anticodon.
24.
Black fur in mince (B) is dominated to brown fur (b). Short tails (T) is dominant to long tails (t). What proportion of the offspring of the cross BbTt and BBtt will have black fur and long tails?
Correct Answer
C. 6/16
Explanation
The cross BbTt and BBtt will result in offspring with the genotypes BbTt, Bbtt, BBTt, and BBtt. Out of these four genotypes, only the genotype BbTt will have both black fur and long tails. Therefore, the proportion of offspring with black fur and long tails is 1 out of 4 possible genotypes, which is equal to 1/4. Simplifying 1/4, we get 4/16. Therefore, the answer is 4/16, which can be further simplified to 1/4 or 6/16.
25.
Which best describes the key to DNA storing genetic information that is unique to each individual organism?
Correct Answer
D. The sequence of nitrogenous bases in nucleotides
Explanation
The sequence of nitrogenous bases in nucleotides is the key to DNA storing genetic information that is unique to each individual organism. The arrangement of these bases (adenine, thymine, cytosine, and guanine) in specific order forms the genetic code that determines the characteristics and traits of an organism. This sequence is what makes each individual's DNA unique and is responsible for encoding the instructions for protein synthesis and other biological processes.
26.
Gene regulation is accomplished by
Correct Answer
D. All of These
Explanation
Gene regulation is a complex process that involves controlling the expression of genes. This can be achieved through various mechanisms, including controlling the amount of mRNA transcribed, controlling the rate of translation, and controlling the activity of a protein product. All of these mechanisms play a role in regulating gene expression and ensuring that genes are expressed at the right time and in the right amount. Therefore, the correct answer is "All of These".
27.
Transcription is the process of
Correct Answer
D. Synthesizing RNA based on information in DNA
Explanation
Transcription is the process of synthesizing RNA based on information in DNA. This process occurs in the nucleus of a cell and involves the enzyme RNA polymerase. During transcription, the DNA molecule is unwound and one strand serves as a template for the synthesis of a complementary RNA molecule. This RNA molecule, known as messenger RNA (mRNA), carries the genetic information from the DNA to the ribosomes in the cytoplasm, where it is used as a template for protein synthesis. Therefore, the correct answer is synthesizing RNA based on information in DNA.
28.
Which true of a pea plant that has the genetic makeup designated as PpYyTt?
Correct Answer
A. Heterozygous for all traits shown
Explanation
The genetic makeup designated as PpYyTt indicates that the pea plant has two different alleles for each trait (heterozygous). Since the question states "for all traits shown," it implies that the plant has multiple traits. Therefore, the correct answer is that the plant is heterozygous for all traits shown.
29.
Translation specifically refers to
Correct Answer
D. Assembly of amino acids according to an RNA template
Explanation
Translation specifically refers to the process of assembling amino acids according to an RNA template. During translation, the mRNA molecule carries the genetic information from the DNA molecule to the ribosomes, where it is used as a template to synthesize a specific sequence of amino acids. This process occurs in the cytoplasm of cells, not within the nucleus. Therefore, the correct answer is the assembly of amino acids according to an RNA template.
30.
A codon with the sequence GAU would be recognized by the anticodon
Correct Answer
C. CUA
Explanation
The given codon sequence is GAU. In RNA, the complementary anticodon sequence for GAU would be CUA. The anticodon is a sequence of three nucleotides found on transfer RNA (tRNA) molecules. It pairs with the codon on messenger RNA (mRNA) during protein synthesis. In this case, the anticodon CUA would pair with the codon GAU, indicating the specific amino acid to be incorporated into the growing protein chain.
31.
A fairly common genetic disorder caused by inability to synthesize a protein that transports Cl- across the cell membrane, symptoms include build up of mucus in the lungs, involves mutations that affect the amino acid Phe508 and chromosomes #7 is
Correct Answer
A. Cystic Fibrosis
Explanation
Cystic Fibrosis is a genetic disorder that is caused by a mutation affecting the amino acid Phe508 and chromosomes #7. This mutation leads to the inability to synthesize a protein that transports Cl- across the cell membrane. As a result, individuals with cystic fibrosis experience a build-up of mucus in the lungs, which can lead to respiratory problems. This explanation fits with the given symptoms and genetic information provided.
32.
In a cross between parents who both exhibit the dominant curly (C) and dark (D) haired traits, one child has straight, light colored hair. What is the hair genotype of the parents that were crossed?
Correct Answer
D. CcDd x CcDd
Explanation
The correct answer is CcDd x CcDd. This is because the child has straight, light colored hair, which indicates that they have a genotype of ccdd. In order for the child to have this genotype, both parents must have at least one copy of the recessive alleles for both traits. The CcDd genotype allows for the possibility of passing on both recessive alleles to the child, resulting in their phenotype.
33.
When two parents that are heterozygous for a trait are crossbred the genotype of the offspring in terms of dominant and recessive alleles would be
Correct Answer
C. 1:2:1
Explanation
When two parents that are heterozygous for a trait are crossbred, the genotype of the offspring in terms of dominant and recessive alleles would be 1:2:1. This means that for every one individual with a homozygous dominant genotype, there will be two individuals with a heterozygous genotype, and one individual with a homozygous recessive genotype. This ratio is known as the Mendelian ratio and is commonly observed in genetic crosses involving a single trait.
34.
In crossing a homozygous recessive for a single trait with a heterozygote, what is the chance of getting an offspring with the recessive phenotype?
Correct Answer
A. 50%
Explanation
When crossing a homozygous recessive individual with a heterozygous individual, the offspring have a 50% chance of inheriting the recessive phenotype. This is because the heterozygous individual carries one dominant allele and one recessive allele, and when crossed with a homozygous recessive individual, there is a 50% chance that the offspring will inherit the recessive allele and display the recessive phenotype.
35.
If a segment of DNA with the base sequence CTAGC was used as a template for RNA synthesis, the sequence of the bases in RNA would be
Correct Answer
B. GAUCG
Explanation
The question asks for the sequence of bases in RNA if a segment of DNA with the base sequence CTAGC is used as a template for RNA synthesis. In RNA, the base thymine (T) is replaced by uracil (U). Therefore, the RNA sequence would be GAUCG, which is the correct answer.
36.
Inclusion of 3 nitrogenous bases in a codon is necessary for
Correct Answer
D. Coding for 20 different amino acids
Explanation
The inclusion of 3 nitrogenous bases in a codon is necessary for coding for 20 different amino acids. A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid. There are 4 different nitrogenous bases in DNA (adenine, cytosine, guanine, and thymine), and by combining them in different sequences of three, it is possible to create 64 different codons. Since there are only 20 different amino acids, some amino acids are coded by multiple codons, allowing for redundancy in the genetic code. Therefore, the inclusion of 3 nitrogenous bases in a codon is necessary for coding for all 20 different amino acids.
37.
A sexually reproducing animal has two unlinked genes. Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
Correct Answer
C. HT
Explanation
In this question, the genotype of the animal is given as HhTt. This means that the animal has two unlinked genes, one for H and one for T. The possible genotypes in a gamete are formed by separating the genes. Therefore, the possible genotypes in a gamete from this organism are HT, which represents one gene for H and one gene for T.
38.
If a double-stranded DNA molecule contains 30% T, it contains _____% G?
Correct Answer
D. 20%
Explanation
If a double-stranded DNA molecule contains 30% T, it means that the other complementary strand also contains 30% A since T always pairs with A in DNA. The total percentage of T and A together is 60%. Since DNA is made up of only four nucleotides (A, T, G, C), the remaining percentage must be divided equally between G and C. Therefore, the DNA molecule contains 20% G.
39.
Evolution is a major biological concept because
Correct Answer
D. All of these
Explanation
Evolution is a major biological concept because it unites all of biology. It is the fundamental process that explains how living things change over time, leading to the presence of millions of species on Earth. By understanding evolution, we can comprehend the diversity of life, the relationships between different organisms, and how they have adapted to their environments. Therefore, all of the given statements are correct, emphasizing the significance of evolution in the field of biology.
40.
Many of the important thermal properties of water that are important for sustaining life result from
Correct Answer
D. Hydrogen Bonds
Explanation
Hydrogen bonds are responsible for many of the important thermal properties of water that are crucial for sustaining life. These bonds occur between the hydrogen atoms of one water molecule and the oxygen atom of another water molecule. They are relatively weak individually but collectively, they create a network of intermolecular forces that give water its unique properties. Hydrogen bonds allow water to have a high boiling point, high specific heat capacity, and high heat of vaporization. These properties enable water to regulate temperature, transport nutrients, and provide a stable environment for biological processes.
41.
On a percentage basis, organisms consist of about ____% water
Correct Answer
A. 70
Explanation
Organisms consist of about 70% water because water is an essential component of living organisms. It plays a vital role in various biological processes such as transportation of nutrients, removal of waste, and regulation of body temperature. Water is also a major constituent of cells and helps maintain their structure and function. Therefore, the high percentage of water in organisms is necessary for their survival and overall functioning.
42.
Ribose and deoxyribose sugars are found in all DNA and RNA and are
Correct Answer
B. Monosaccharides
Explanation
Ribose and deoxyribose sugars are found in all DNA and RNA. These sugars are classified as monosaccharides, which means they are single sugar units. Monosaccharides are the simplest form of carbohydrates and serve as the basic building blocks for more complex carbohydrates like polysaccharides. While proteins are also important biomolecules, they are not directly related to ribose and deoxyribose sugars. Glucose is a different type of monosaccharide and not specifically related to ribose and deoxyribose sugars.
43.
Phospholipids are an unusual lipid because
Correct Answer
A. They contain a polar end
Explanation
Phospholipids are classified as unusual lipids because they contain a polar end. Unlike other lipids, which are typically hydrophobic (repel water), phospholipids have a hydrophilic (attracted to water) head and a hydrophobic tail. This unique structure allows phospholipids to form the basic building blocks of cell membranes. The polar end of phospholipids interacts with water, while the fatty acid tails face inward, creating a barrier that separates the inside of the cell from its external environment. This property is essential for maintaining the integrity and functionality of cell membranes.
44.
An important function of the __________ is maintaining cell shape and providing an anchor for organelles
Correct Answer
B. Cytoskeleton
Explanation
The cytoskeleton is responsible for maintaining the shape of the cell and providing a structural framework. It consists of protein filaments that form a network throughout the cytoplasm, giving the cell its shape and providing support. Additionally, the cytoskeleton acts as an anchor for organelles, helping to position them within the cell. Therefore, the cytoskeleton performs the important function of maintaining cell shape and providing an anchor for organelles.
45.
A primary function of protein is
Correct Answer
D. All of these
Explanation
Proteins serve various functions in the body, including acting as enzymes, providing structural support, and contributing to energy production. Enzymes are proteins that catalyze biochemical reactions, allowing them to occur at a faster rate. Proteins also play a crucial role in maintaining the structure and integrity of cells, tissues, and organs. Additionally, proteins can be broken down to release energy when needed. Therefore, the correct answer is "All of these" as proteins perform all these functions in the body.
46.
An example of a transport process that requires energy is
Correct Answer
D. Both b & c
Explanation
Both facilitated diffusion and active transport require energy because they involve the movement of molecules against their concentration gradient. Facilitated diffusion uses carrier proteins to transport molecules across the cell membrane, while active transport uses ATP to pump molecules across the membrane. In both cases, energy is required to move molecules from an area of lower concentration to an area of higher concentration.
47.
Lipids do not dissolve easily in water because
Correct Answer
A. They are nonpolar
Explanation
Lipids do not dissolve easily in water because they are nonpolar. Water is a polar molecule, meaning it has a slight positive charge on one end and a slight negative charge on the other. Nonpolar molecules, like lipids, do not have a charge and are therefore not attracted to water molecules. This lack of attraction makes it difficult for lipids to dissolve in water, resulting in the separation of the two substances.
48.
All nucleotides consist of a sugar, a phosphate and a
Correct Answer
A. Base
Explanation
All nucleotides consist of a sugar, a phosphate, and a base. The base is a nitrogenous molecule that is responsible for the genetic information in DNA and RNA. It pairs with another complementary base to form the rungs of the DNA double helix or to create the sequence of RNA. The base can be adenine (A), thymine (T), cytosine (C), guanine (G) in DNA, or adenine (A), uracil (U), cytosine (C), guanine (G) in RNA.
49.
Which is true of starch, glycogen and cellulose
Correct Answer
D. All are true
Explanation
Starch, glycogen, and cellulose are all polysaccharides, meaning they are composed of multiple sugar molecules bonded together. Additionally, they consist of repeating glucose molecules, which are linked in different ways in each of these compounds. Lastly, starch and glycogen are synthesized in plants and animals respectively, while cellulose is synthesized in plants. Therefore, all of the statements provided are true.
50.
The building blocks of proteins are
Correct Answer
C. Amino acids
Explanation
Proteins are composed of long chains of amino acids, which are the building blocks of proteins. Amino acids are organic compounds that contain an amino group (-NH2) and a carboxyl group (-COOH). They are linked together by peptide bonds, forming polypeptide chains. Nucleic acids, on the other hand, are responsible for storing and transmitting genetic information, while polysaccharides are complex carbohydrates. Therefore, amino acids are the correct answer as they are specifically associated with protein synthesis.