1.
If a pea plant were homozygous recessive for height, how would its alleles be represented?
Correct Answer
C. Tt
Explanation
If a pea plant is homozygous recessive for height, it means that it has two identical recessive alleles for the height trait. In this case, the alleles would be represented by "tt". The lowercase letters indicate the recessive allele, and since both alleles are the same, it is homozygous.
2.
In the diagram to the right, what is structure B?
Correct Answer
B. Mitochondrial matrix
Explanation
Structure B in the diagram is the mitochondrial matrix. The mitochondrial matrix is the fluid-filled space enclosed by the inner membrane of the mitochondria. It contains enzymes that are involved in various metabolic reactions, including the citric acid cycle. The matrix also houses mitochondrial DNA and ribosomes, which are essential for protein synthesis within the mitochondria.
3.
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, it is called heterozygous. This means that the organism has inherited two different versions of a gene for a specific trait. In heterozygous individuals, one allele may be dominant and the other recessive, or both alleles may have equal influence on the trait. Heterozygosity often leads to a blend of traits or the expression of one dominant allele over the other recessive allele.
4.
Hair color and eye color are examples of a person's.
Correct Answer
D. pHenotype.
Explanation
Hair color and eye color are examples of a person's phenotype. Phenotype refers to the observable characteristics or traits of an individual, including physical attributes such as hair color and eye color. These traits are determined by a combination of genetic factors (genotype) and environmental influences. In this case, the question is asking for the term that describes the physical traits themselves, rather than the underlying genetic makeup or the specific alleles responsible for those traits. Therefore, the correct answer is phenotype.
5.
Mendel's second law of genetics, the law of independent assortment, is one explanation of the
Correct Answer
B. Genetic variation within species.
Explanation
Mendel's second law of genetics, the law of independent assortment, states that during gamete formation, the segregation of one pair of alleles is independent of the segregation of another pair of alleles. This means that different traits are inherited independently of each other, leading to genetic variation within a species. This law explains why offspring can have different combinations of traits from their parents, contributing to the overall genetic diversity within a population.
6.
Any of the alternative forms of a gene that occurs at a specific place on a chromosome are known as ___.
Correct Answer
A. Alleles
Explanation
Alleles are alternative forms of a gene that occur at a specific place on a chromosome. They are responsible for the variations in a particular trait or characteristic. Each individual inherits two alleles for each gene, one from each parent. These alleles can be either dominant or recessive, and they determine the expression of the trait. Therefore, alleles are the correct answer for this question.
7.
A chart or "family tree" that tracks which members of a family have a particular trait is called a ___.
Correct Answer
A. Pedigree
Explanation
A chart or "family tree" that tracks which members of a family have a particular trait is called a pedigree. This is a common tool used in genetics to study the inheritance of traits within a family. It helps to visualize patterns of inheritance and identify individuals who may be carriers or affected by a specific trait or disease.
8.
___ 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 known as the father of modern genetics. He conducted experiments with pea plants and discovered the two fundamental laws of genetics, known as the law of segregation and the law of independent assortment. Mendel's work laid the foundation for our understanding of inheritance and heredity, and his discoveries are still widely studied and applied in the field of genetics today.
9.
___ 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 refers to the pattern of inheritance where a gene for a particular trait is located on the X-chromosome. This means that the trait is more commonly observed in males because they only have one X-chromosome, while females have two. If a male inherits the gene for a sex-linked disorder, he will express the disorder because he does not have another X-chromosome to compensate for the affected gene. However, females have a higher chance of being carriers of the disorder since they have two X-chromosomes.
10.
In humans, a ___ cell has ___ chromosomes.
Correct Answer
B. Haploid ... 23
Explanation
In humans, a haploid cell has 23 chromosomes. Haploid cells are reproductive cells, such as sperm and eggs, that contain half the number of chromosomes as diploid cells. This is because during the process of meiosis, the number of chromosomes is reduced by half. Therefore, haploid cells in humans have 23 chromosomes, which is the correct answer.
11.
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 the form of nuclear division that specifically divides a diploid cell into haploid cells, which are gametes. Mitosis, on the other hand, is a form of nuclear division that produces two identical diploid cells. Cellular regeneration refers to the process of replacing damaged or lost cells, and binary fission is a type of cell division in prokaryotes where the cell divides into two identical cells.
12.
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. In diploid cells, one copy of each chromosome is inherited from each parent, resulting in a total of two copies of each chromosome. This allows for genetic diversity and stability in the cell, as any potential mutations or damage to one copy of a chromosome can be compensated for by the other copy. Diploid cells are found in most tissues of the body, except for the reproductive cells (gametes) which are haploid, meaning they only have one copy of each chromosome.
13.
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 term "ovum" refers to the mature, haploid female reproductive cell, which is released from the ovary during ovulation and can be fertilized by a sperm to form a zygote. The term "egg cell" is another way to refer to the same female gamete. Both terms are commonly used in biology to describe the female reproductive cell involved in sexual reproduction.
14.
Each set of three nucleotides on mRNA coding for an amino acid is referred to as a(n) ___.
Correct Answer
A. Codon
Explanation
A codon refers to a set of three nucleotides on mRNA that codes for a specific amino acid. It acts as a template during protein synthesis, where each codon corresponds to a specific amino acid. The ribosome reads the codons and helps in the translation process. An anticodon, on the other hand, is found on tRNA and pairs with the codon during translation. A ribosome is a cellular structure involved in protein synthesis, while a base pair refers to the pairing of nucleotide bases in DNA or RNA.
15.
Messenger RNA is formed in the process of ___.
Correct Answer
A. Transcription
Explanation
Messenger RNA is formed in the process of transcription. Transcription is the process by which the information encoded in DNA is copied into a complementary RNA molecule. During transcription, an enzyme called RNA polymerase binds to a specific region of DNA called the promoter and separates the DNA strands. It then uses one of the DNA strands as a template to synthesize a complementary RNA molecule, including the messenger RNA (mRNA). This mRNA molecule carries the genetic information from the DNA to the ribosomes, where it is translated into a protein during the process of translation.
16.
The process by which a DNA molecule is copied is ___.
Correct Answer
C. Replication
Explanation
The process by which a DNA molecule is copied is called replication. During replication, the DNA molecule unwinds and separates into two strands. Each strand 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.
17.
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, with the help of Rosalind Franklin, were able to determine the structure of DNA. They proposed that DNA is in the shape of a double helix, which consists of two strands that are twisted around each other. This discovery was groundbreaking as it provided crucial insights into the replication and transmission of genetic information.
18.
Which DNA sequence produced an mRNA strand with the sequence AGUACA?
Correct Answer
B. TCATGT
Explanation
The mRNA sequence is complementary to the DNA sequence, so in order to find the DNA sequence that produces an mRNA strand with the sequence AGUACA, we need to find the complementary sequence of AGUACA which is UGACUG. Among the given options, the only DNA sequence that is complementary to UGACUG is TCATGT. Therefore, TCATGT is the correct answer.
19.
Which of the following is a pair of complementary bases?
Correct Answer
B. Thymine and adenine
Explanation
Thymine and adenine are a pair of complementary bases because they form a base pair in DNA. In DNA, thymine always pairs with adenine through hydrogen bonding, creating a stable double-stranded structure. This pairing is essential for DNA replication and transcription processes. Cytosine and cytosine cannot form a base pair, and thymine and cytosine also cannot form a base pair. Adenine and guanine are not complementary bases, as they do not pair with each other in DNA.
20.
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 carbon atoms to form stable covalent bonds with other carbon atoms and with a variety of other elements. This versatility of carbon bonding allows for the formation of a wide range of organic molecules, each with its own distinct structure and properties.
21.
Organic compounds always contain the element ____.
Correct Answer
A. Carbon
Explanation
Organic compounds are defined as compounds that contain carbon atoms bonded to hydrogen atoms and may also contain other elements such as nitrogen, oxygen, sulfur, and halogens. However, the presence of carbon is a fundamental characteristic of organic compounds, distinguishing them from inorganic compounds which do not contain carbon. Therefore, the correct answer is carbon.
22.
Which of the following is NOT a characteristic of RNA?
Correct Answer
B. It contains thymine.
Explanation
RNA is a single-stranded molecule that contains uracil instead of thymine. Thymine is found in DNA, while uracil is found in RNA. RNA is involved in the transfer of genetic information from DNA to the ribosome for protein synthesis. Therefore, the statement "It contains thymine" is incorrect as thymine is not present in RNA.
23.
Which of the following describes DNA?
Correct Answer
C. It controls the production of proteins.
Explanation
DNA controls the production of proteins. This is because DNA contains the genetic information that is used by cells to synthesize proteins. DNA is transcribed into RNA, which is then translated into proteins. Proteins are essential for various cellular functions and play a crucial role in determining an organism's traits and characteristics. Therefore, the statement that DNA controls the production of proteins is accurate.
24.
The functional group -NH2 is called the ____.
Correct Answer
A. Amino group
Explanation
The functional group -NH2 is called the amino group. This group consists of a nitrogen atom bonded to two hydrogen atoms and is commonly found in organic compounds such as amino acids, proteins, and amines. The presence of the amino group in a molecule imparts basic properties, as it can accept a proton to form a positively charged ammonium ion.
25.
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 repeating glucose units. It forms the primary structural component of plant cell walls and provides rigidity and strength to plant cells. Starch, on the other hand, is a storage form of carbohydrate in plants, while enzymes and RNA are not carbohydrates at all.
26.
Which of the following monomers make up a lipid?
Correct Answer
A. Glycerol and fatty acid
Explanation
Lipids are organic molecules that are insoluble in water and include fats, oils, and waxes. The monomers that make up a lipid are glycerol and fatty acids. Glycerol is a three-carbon alcohol, while fatty acids are long hydrocarbon chains with a carboxyl group at one end. These monomers combine through dehydration synthesis, forming ester bonds between the hydroxyl groups of glycerol and the carboxyl groups of fatty acids. This results in the formation of triglycerides, the main type of lipid found in the body and in food.
27.
Which of the following is NOT a nucleotide found in DNA?
Correct Answer
C. Uracil
Explanation
Uracil is not a nucleotide found in DNA. DNA is composed of four nucleotides: adenine, cytosine, guanine, and thymine. Uracil, on the other hand, is a nucleotide found in RNA. RNA uses uracil instead of thymine as one of its building blocks. Thymine is specific to DNA and is not present in RNA. Therefore, uracil is the correct answer as it is not a nucleotide found in DNA.
28.
Which of the following is a polymer of nucleotides?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic acid is the correct answer because it is a polymer of nucleotides. Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. These polymers are composed of repeating units called nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. Nucleic acids play a crucial role in storing and transmitting genetic information in living organisms.
29.
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 organic compounds that contain an amino group (-NH2) and a carboxyl group (-COOH). They are the building blocks of proteins. Proteins are large, complex molecules made up of chains of amino acids linked together by peptide bonds. They play a crucial role in various biological processes and are involved in the structure, function, and regulation of cells and tissues in the body.
30.
What is the main function of the Krebs cycle?
Correct Answer
C. Producing molecules that carry high-energy electrons to the electron transport chain
Explanation
The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. Its main function is to produce molecules that carry high-energy electrons to the electron transport chain. These high-energy electrons are generated through the breakdown of pyruvate molecules, which release energy in the form of NADH. The Krebs cycle also produces carbon dioxide as a waste product. The electrons carried by NADH are then used in the electron transport chain to generate ATP, the cell's main source of energy.
31.
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 is responsible for transferring electrons from photosystem II to photosystem I, creating a proton gradient across the membrane, which is used to generate ATP. The proteins in the electron transport chain facilitate the flow of electrons and play a crucial role in the production of energy-rich molecules during photosynthesis.
32.
The process by which plants use sunlight to make glucose is called ___.
Correct Answer
A. pHotosynthesis
Explanation
Photosynthesis is the correct answer because it is the process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen. During photosynthesis, plants capture energy from sunlight and use it to produce food (glucose) for themselves. This process occurs in the chloroplasts of plant cells and is essential for the survival of plants and the production of oxygen in the atmosphere. Cellular respiration, the cell cycle, and mitosis are not the correct answers as they are unrelated processes in plant biology.