1.
If a pea plant were homozygous recessive for height, how would its alleles be represented?
Correct Answer
A. Tt
Explanation
If a pea plant is homozygous recessive for height, it means that both of its alleles for height are the same and recessive. In this case, the alleles would be represented by the lowercase letter "t". The "t" represents the recessive allele for height, indicating that the plant will have a short height.
2.
In humans, a ___ cell has ___ chromosomes.
Correct Answer
B. Haploid ... 23
Explanation
In humans, a haploid cell has 23 chromosomes. Haploid cells are cells that contain half the number of chromosomes found in diploid cells. In humans, diploid cells have 46 chromosomes, with 23 inherited from each parent. However, haploid cells, such as sperm and egg cells, only have 23 chromosomes, as they are produced through a process called meiosis, which reduces the number of chromosomes in the cell.
3.
A(n) ___ involves the insertion or deletion of a single base in a DNA molecule.
Correct Answer
A. Frameshift mutation
Explanation
A frameshift mutation involves the insertion or deletion of a single base in a DNA molecule. This type of mutation can disrupt the reading frame of the DNA sequence, causing a shift in the way the genetic code is read. As a result, the entire sequence of amino acids that are produced during protein synthesis can be altered, leading to a non-functional or partially functional protein. Frameshift mutations can have significant effects on an organism's phenotype and are often associated with genetic disorders.
4.
Which DNA sequence produced an mRNA strand with the sequence AGUACA?
Correct Answer
B. TCATGT
Explanation
The mRNA strand with the sequence AGUACA can be produced from the DNA sequence TCATGT. This is because the DNA sequence is transcribed into mRNA by replacing each DNA base with its complementary RNA base. In this case, T (thymine) is replaced with A (adenine), C (cytosine) is replaced with G (guanine), A (adenine) is replaced with U (uracil), G (guanine) is replaced with C (cytosine), and T (thymine) is replaced with A (adenine), resulting in the mRNA sequence AGUACA.
5.
Which of the following is a pair of complementary bases?
Correct Answer
C. Thymine and adenine
Explanation
Thymine and adenine are a pair of complementary bases because they form a base pair in DNA. Adenine always pairs with thymine, and thymine always pairs with adenine through hydrogen bonding. This base pairing is essential for DNA replication and the accurate transmission of genetic information.
6.
There are literally hundreds of thousands of different organic molecules. Which statement best explains how this is possible?
Correct Answer
B. Carbon is unique in that it can make four chemical bonds.
Explanation
Carbon is unique in that it can make four chemical bonds. This allows it to form a wide variety of organic molecules. Unlike other elements, carbon has the ability to form stable covalent bonds with other carbon atoms, as well as with other elements such as hydrogen, oxygen, nitrogen, and sulfur. This versatility in bonding allows carbon to create complex and diverse molecular structures, leading to the vast number of organic compounds found in nature.
7.
Which of the following is NOT a characteristic of RNA?
Correct Answer
B. It contains thymine.
Explanation
RNA is a nucleic acid that is made up of a single strand, unlike DNA which has two strands. It contains uracil instead of thymine. RNA is responsible for transferring genetic information from DNA to the ribosome for protein synthesis. Therefore, the characteristic that is NOT true for RNA is that it contains thymine.
8.
Which of the following describes DNA?
Correct Answer
C. It controls the production of proteins.
Explanation
DNA controls the production of proteins. DNA contains the genetic instructions that determine the sequence of amino acids in proteins. It does not contain uracil, as uracil is found in RNA. It also does not contain the sugar ribose, as DNA contains the sugar deoxyribose. DNA itself is not made of amino acids; rather, it is composed of nucleotides.
9.
Which of the following is a structural form of carbohydrate?
Correct Answer
A. Cellulose
Explanation
Cellulose is a structural form of carbohydrate because it is a complex polysaccharide made up of glucose molecules linked together in a linear chain. It forms the main structural component of plant cell walls and provides rigidity and support to the plant. Starch, on the other hand, is a storage form of carbohydrate, while enzyme and RNA are not carbohydrates at all.
10.
Which of the following monomers make up a lipid?
Correct Answer
A. Glycerol and fatty acid
Explanation
Lipids are organic compounds that are insoluble in water and are an important component of cell membranes and energy storage. The monomers that make up a lipid are glycerol and fatty acids. Glycerol is a three-carbon alcohol molecule, while fatty acids are long chains of hydrocarbons with a carboxyl group at one end. These two monomers combine through a dehydration synthesis reaction to form a lipid molecule, with the fatty acids attaching to the glycerol backbone. Therefore, the correct answer is glycerol and fatty acid.
11.
Which of the following is NOT a nucleotide found in DNA?
Correct Answer
D. Uracil
Explanation
Uracil is not a nucleotide found in DNA. DNA is made up of four nucleotides: adenine, cytosine, guanine, and thymine. Uracil is found in RNA instead of DNA. RNA is a different type of nucleic acid that uses uracil instead of thymine. Therefore, uracil is the correct answer as it is not a nucleotide found in DNA.
12.
Which of the following is a polymer of nucleotides?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic Acid is the correct answer because it is composed of nucleotides. Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. These polymers are made up of repeating units of nucleotides, each consisting of a sugar, a phosphate group, and a nitrogenous base. Proteins, carbohydrates, and lipids are not polymers of nucleotides, but rather have different molecular structures and compositions.
13.
Which of the following is a polymer of amino acids?
Correct Answer
A. Protein
Explanation
Protein is a polymer of amino acids. Amino acids are the building blocks of proteins, and they are linked together through peptide bonds to form long chains. These chains then fold into complex three-dimensional structures, giving proteins their unique functions and properties. Therefore, protein is the correct answer as it is composed of amino acid polymers.
14.
When an organism has two alleles at a particular locus that are different, the organism is called ______________.
Correct Answer
C. Heterozygous
Explanation
When an organism has two alleles at a particular locus that are different, the organism is called heterozygous. This means that the organism has inherited two different versions of a gene for a particular trait. In heterozygous individuals, one allele may be dominant and the other recessive, resulting in the expression of the dominant allele. This can lead to a variety of phenotypic outcomes depending on the specific alleles involved.
15.
Hair color and eye color are examples of a person's ______________.
Correct Answer
B. pHenotype.
Explanation
Hair color and eye color are examples of a person's phenotype because they are observable characteristics that result from the interaction between an individual's genotype and their environment. Phenotype refers to the physical traits and characteristics that are expressed or visible in an organism. In this case, hair color and eye color are determined by specific genes, but they can also be influenced by factors such as sunlight exposure or hair dye. Therefore, the correct answer is phenotype.
16.
Mendel's second law of genetics, the law of independent assortment, is an explanation of the _________________.
Correct Answer
D. Genetic variation within species.
Explanation
Mendel's second law of genetics, the law of independent assortment, states that the alleles for different traits segregate independently of each other during gamete formation. This means that the combination of alleles in one gamete does not influence the combination of alleles in another gamete. As a result, this process leads to genetic variation within a species, as different combinations of alleles can be passed on to offspring.
17.
Any of the alternative forms of a gene that occurs at a specific place on a chromosome are known as ______________.
Correct Answer
B. Alleles
Explanation
Alleles refer to any of the alternative forms of a gene that occur at a specific place on a chromosome. They are responsible for the variations in traits that individuals can possess. Genes are the segments of DNA that provide instructions for the development and functioning of organisms. Chromosomes are structures made up of DNA and proteins that carry genes. Recessive traits are characteristics that are only expressed when an individual has two copies of the recessive allele.
18.
A chart or "family tree" that tracks which members of a family have a particular trait is called a _________________.
Correct Answer
D. Pedigree
Explanation
A chart or "family tree" that tracks which members of a family have a particular trait is called a pedigree. This is because a pedigree is a visual representation of the inheritance patterns of specific traits within a family. It helps to identify the presence or absence of a trait in different generations and can be useful in studying genetic disorders and inheritance patterns.
19.
__________________ studied traits of pea plants and discovered the two fundamental laws of genetics.
Correct Answer
A. Mendel
Explanation
Mendel is the correct answer because he is widely known for his experiments with pea plants and his discovery of the two fundamental laws of genetics, namely the law of segregation and the law of independent assortment. Mendel's work laid the foundation for modern genetics and his discoveries revolutionized the understanding of inheritance and heredity.
20.
_______________ is a pattern of inheritance in which the gene for a trait is located on the X-chromosome, thereby creating disorders that are much more common in males than females.
Correct Answer
D. Sex-linked
Explanation
Sex-linked inheritance is a pattern in which the gene for a trait is located on the X-chromosome. This means that the trait is more common in males because they only have one X-chromosome, while females have two. If a male inherits the gene for the trait on his X-chromosome, he will express the trait because there is no other copy of the gene to mask it. However, females need to inherit the gene on both X-chromosomes to express the trait. This is why sex-linked disorders are more commonly seen in males.
21.
A form of nuclear division that divides a diploid cell into haploid cells and produces gametes is known as _____________.
Correct Answer
B. Meiosis
Explanation
Meiosis is the correct answer because it is a form of nuclear division that specifically occurs in diploid cells and results in the production of haploid cells, which are the gametes. Mitosis, on the other hand, is a form of nuclear division that produces identical copies of the original cell, maintaining the same ploidy level. Cellular regeneration refers to the process of replacing damaged or lost cells in an organism, and binary fission is a type of cell division that occurs in prokaryotes, not in diploid cells.
22.
A cell that has two copies of each chromosome is said to be _____________.
Correct Answer
A. Diploid
Explanation
A cell that has two copies of each chromosome is said to be diploid. This means that it contains two sets of chromosomes, one set inherited from each parent. This is in contrast to haploid cells, which only have one set of chromosomes, and triploid cells, which have three sets of chromosomes. A gamete, on the other hand, is a reproductive cell (such as sperm or egg) that is haploid, containing only one set of chromosomes.
23.
A female gamete _________________.
Correct Answer
B. Is called an ovum or an egg cell.
Explanation
The female gamete is called an ovum or an egg cell. The ovum is produced in the ovaries, not the testes. Spermatocyte is the term used for male gametes, and a polar body is a small non-functional cell that is produced during the process of oogenesis.
24.
Each set of three nucleotides on mRNA coding for an amino acid is referred to as a(n) __________________.
Correct Answer
A. Codon
Explanation
A set of three nucleotides on mRNA that codes for an amino acid is called a codon. Codons are essential in the process of protein synthesis as they determine the sequence of amino acids that will be incorporated into the growing polypeptide chain. Each codon corresponds to a specific amino acid or a stop signal. The correct answer is codon.
25.
Messenger RNA is formed in the process of _______________.
Correct Answer
B. Transcription
Explanation
Messenger RNA is formed in the process of transcription. Transcription is the process by which the DNA sequence is copied into a complementary RNA molecule. During transcription, the enzyme RNA polymerase binds to the DNA strand and synthesizes a strand of RNA that is complementary to the DNA template. This RNA molecule, known as messenger RNA (mRNA), carries the genetic information from the DNA to the ribosomes, where it is translated into a protein. Therefore, transcription is the correct process in which messenger RNA is formed.
26.
The process by which a DNA molecule is copied is _______________.
Correct Answer
C. Replication
Explanation
The correct answer is replication. Replication is the process in which a DNA molecule is copied. During replication, the double-stranded DNA molecule unwinds and separates into two strands. Each strand then serves as a template for the synthesis of a new complementary strand, resulting in two identical DNA molecules. This process is essential for cell division and the transmission of genetic information from one generation to the next. Transcription is the process of synthesizing RNA from a DNA template, while translation is the process of synthesizing proteins from RNA. Mutation refers to a change in the DNA sequence.
27.
Watson and Crick, with the help of Rosalind Franklin, were the first to suggest that DNA is ________________.
Correct Answer
C. The shape of a double helix
Explanation
Watson and Crick, along with the assistance of Rosalind Franklin, proposed that DNA has the shape of a double helix. This means that DNA is structured as two strands twisted around each other in a spiral staircase-like manner. This discovery was groundbreaking as it provided crucial insights into the structure and function of DNA, leading to a better understanding of genetics and heredity.
28.
Organic compounds always contain the element ____________.
Correct Answer
A. Carbon
Explanation
Organic compounds are compounds that contain carbon atoms bonded to other carbon atoms and other elements such as hydrogen, oxygen, nitrogen, sulfur, and phosphorus. Carbon is the central element in organic compounds and is essential for the formation of the complex structures and diverse properties exhibited by organic compounds. Therefore, the correct answer is carbon.
29.
Which phrase best describes the electron transport chain in photosynthesis?
Correct Answer
C. A series of proteins located in the thylakoid membrane.
Explanation
The electron transport chain in photosynthesis is a series of proteins located in the thylakoid membrane. This chain plays a crucial role in the process of converting light energy into chemical energy by transferring electrons from one protein to another, ultimately leading to the production of ATP and NADPH. The thylakoid membrane is where the photosynthetic pigments are located, and it is the site where the light reactions of photosynthesis occur. Therefore, the electron transport chain being located in the thylakoid membrane is the most accurate description.
30.
The process by which plants use sunlight to make glucose is called ____________.
Correct Answer
D. pHotosynthesis
Explanation
Photosynthesis is the correct answer because it is the process through which plants convert sunlight into glucose. During photosynthesis, plants use chlorophyll in their cells to capture sunlight energy and convert it into chemical energy in the form of glucose. This process is crucial for plants as it provides them with the energy they need for growth and survival.
31.
The main light-absorbing molecules found in plant leaves are called ____________.
Correct Answer
C. ChloropHyll
Explanation
Chlorophyll is the correct answer because it is the main light-absorbing pigment found in plant leaves. It is responsible for capturing sunlight energy during photosynthesis. Chloroplasts are the organelles that contain chlorophyll, so they are not the molecules themselves. Thylakoids are membrane structures within chloroplasts where photosynthesis takes place, but they are not the molecules responsible for light absorption. Grana are stacks of thylakoids within chloroplasts, but again, they are not the molecules involved in light absorption.