A&p Exam 1

Mitochondria are referred to as the powerhouse of the cell because they specialize in synthesizing ATP. ATP is the energy currency of the cell, and mitochondria play a crucial role in generating this energy through cellular respiration. They have their own DNA and are capable of producing ATP through oxidative phosphorylation. This process involves the breakdown of glucose and other molecules to release energy, which is then used to produce ATP. Therefore, the term "powerhouse" accurately describes the function of mitochondria in energy production.

The sebaceous gland is most likely to produce sebum, an oily secretion that helps keep skin and hair from becoming dry and brittle. Sebaceous glands are found all over the body, except for the palms of the hands and soles of the feet. They are most abundant on the face and scalp. Sebum acts as a natural moisturizer, lubricating the skin and hair, and also has antimicrobial properties.

The skin performs several functions, including vitamin D synthesis, thermoregulation, acting as a barrier against infection, and sensation. However, it does not directly control blood pressure through negative feedback mechanisms. Blood pressure regulation is primarily controlled by the cardiovascular system, including the heart, blood vessels, and kidneys. Therefore, the correct answer is negative feedback control of blood pressure.

The plasma membrane is composed of a double layer of lipids, known as a bi-layer, which surrounds the cell and acts as a barrier. This lipid bi-layer is embedded with various proteins that perform a variety of functions, such as transporting molecules in and out of the cell, cell signaling, and structural support. Therefore, the correct answer is "lipids and proteins" as these are the main components of the plasma membrane.

Dense regular connective tissue is found in tendons and is made of densely packed collagen fibers. Tendons are fibrous connective tissues that connect muscles to bones, providing strength and stability to the joints. Collagen is the main protein found in tendons, responsible for their strength and flexibility. Therefore, tendons are composed of densely packed collagen fibers, making them strong and resistant to stretching.

Exocrine glands are responsible for secreting substances onto body surfaces or into body cavities through ducts. Sweat, saliva, and tears are all examples of substances that are produced by exocrine glands and are released through ducts. Growth hormone, on the other hand, is produced by the endocrine glands, which release hormones directly into the bloodstream. Therefore, growth hormone would NOT be produced from an exocrine gland.

Jaundice is an abnormal skin color due to excess bilirubin and is usually an indicator of defective or compromised liver function. Bilirubin is a yellow pigment that is produced when red blood cells are broken down. It is normally processed by the liver and excreted in the bile. When the liver is not functioning properly, it may not be able to process bilirubin effectively, leading to its buildup in the body and causing jaundice. Therefore, the correct answer is bilirubin, liver.

When a blood or nerve cell is placed in a hypertonic solution, the concentration of solutes outside the cell is higher than inside the cell. As a result, water will move out of the cell through osmosis, causing the cell to lose water and shrink. This process is known as crenation or shriveling. Therefore, the correct answer is "shrivel (crenate)."

The correct answer is both A and C. The cell's cytoskeleton serves multiple functions. One of its main functions is to provide structural support to the cell, helping to maintain its shape and integrity. Additionally, the cytoskeleton is involved in directing the movement of substances through the cell, including organelles and vesicles. Therefore, the correct answer is both A and C.

Cardiac muscle is the correct answer because it is the only type of muscle tissue that possesses both intercalated discs and striations. Intercalated discs are specialized cell-to-cell junctions that allow for electrical and mechanical coupling between cardiac muscle cells, while striations are the alternating light and dark bands seen under a microscope, indicating the presence of organized contractile proteins. Smooth muscle lacks both intercalated discs and striations, skeletal muscle lacks intercalated discs, and neurons and glia are not muscle tissues.

The shape of the external ear is due to elastic cartilage. Elastic cartilage is a type of cartilage that contains elastic fibers, which give it the ability to be flexible and maintain its shape. This allows the external ear to have its characteristic curved and folded shape, which helps in capturing and funneling sound waves into the ear canal.

The layer between an epithelium and the underlying connective tissue is referred to as the basement membrane. This membrane provides structural support and acts as a barrier between the epithelium and connective tissue. It is composed of specialized proteins and serves as a platform for cell adhesion and communication. The basement membrane also plays a crucial role in regulating the movement of molecules and cells between the epithelium and connective tissue.

Blood is classified as a type of connective tissue because it consists of a liquid ground substance called plasma that contains many cellular components, including platelets. Unlike epithelial tissue, which forms the lining of organs and body cavities, blood does not have a solid structure. Additionally, adipocytes are fat cells and are not found in blood. Collagenous tissue is a type of connective tissue, but it does not accurately describe the ground substance of blood, which is liquid. Therefore, the correct answer is connective, liquid, platelets.

A neuron is a component of nervous tissue and has dendrites which receive signals from other cells.

Water's ability to support life can be attributed to several properties, including cohesion, solvency, and thermal stability. Cohesion refers to the ability of water molecules to stick to each other, allowing for capillary action and the transport of nutrients in plants. Solvency refers to water's ability to dissolve a wide range of substances, making it an excellent solvent for biological reactions. Thermal stability refers to water's high specific heat capacity, which helps to regulate temperature in living organisms. Van der Waals forces, on the other hand, are weak intermolecular forces that are not specific to water and do not play a significant role in its ability to support life.

The correct answer is "internal cellular structures are referred to as cytosomes". This statement is not part of the modern cell theory. The modern cell theory states that all organisms are composed of cells, the cell is the basic functional unit of life, and all cells come from pre-existing cells. However, the term "cytosomes" is not used to refer to internal cellular structures in the modern cell theory.

The stratum corneum is the outermost layer of the epidermis, consisting of dead skin cells that have undergone keratinization. These cells are no longer alive and serve as a protective barrier for the underlying layers of the skin.

The correct answer is "all of the above." A nucleotide such as ATP consists of a monosaccharide, a nitrogenous base, and a phosphate group. The monosaccharide provides the energy, the nitrogenous base determines the specific nucleotide, and the phosphate group helps in transferring energy. Therefore, all three components are present in a nucleotide like ATP.

In parts of the body, such as the urinary bladder, where considerable distension and stretching occurs, transitional epithelium is expected to be found. Transitional epithelium is a specialized type of epithelial tissue that can stretch and accommodate changes in organ volume. It is composed of multiple layers of cells that can change shape and flatten as the organ expands, allowing it to maintain its barrier function while also being flexible. This type of tissue is well-suited for organs that experience frequent changes in volume, such as the urinary bladder.

The dermis is the layer of skin that is important for providing hair with nutrients and contains the piloerector muscle that is responsible for causing "goose bumps". The dermis is the layer of skin beneath the epidermis and is composed of connective tissue. It contains blood vessels, nerves, hair follicles, and sweat glands. The piloerector muscle is attached to the hair follicles and contracts in response to cold or emotional stimuli, causing the hairs to stand up and creating the appearance of "goose bumps".

Melanocytes are pigment-producing cells found in the stratum basale of the epidermis. They are responsible for the development of melanoma, a type of skin cancer. Malignant melanoma is a specific type of melanoma that arises from these melanocytes.

The principle of complementarity describes the relationship between form and function. The study of form is anatomy while the study of function is physiology.

In classical genetics, if a man with X-linked color blindness (recessive X-linked disorder) marries a woman carrying the gene for color blindness but not having the condition, their daughters will inherit one X chromosome from each parent. Since the father's X chromosome carries the color blindness gene and the mother is a carrier, their daughters will inherit one normal X chromosome from the mother and one X chromosome with the color blindness gene from the father. As a result, the daughters will be carriers (heterozygous) for color blindness but will not express the condition themselves. Therefore, the chance of them having a color-blind daughter is 0%.

An active transporter is not part of a common feedback loop because it is responsible for moving molecules across a membrane against their concentration gradient, using energy from ATP. In contrast, a feedback loop typically involves a receptor that detects a stimulus, an integrating center that processes the information, and an effector that produces a response to restore homeostasis. The active transporter does not play a direct role in this process and is therefore not part of a common feedback loop.

The given reaction describes the process of ionization, where sodium chloride (NaCl) dissociates into a sodium cation (Na+) and a chloride anion (Cl-). Sodium chloride is a common electrolyte found in the human body.

Smooth muscle tissue has a single nucleus because it is composed of elongated cells that lack striations and intercalated discs. Unlike skeletal muscle tissue, which has multiple nuclei, smooth muscle tissue is not under voluntary control. The single nucleus in smooth muscle cells helps regulate and coordinate the contractions of these muscles, allowing them to contract and relax in a coordinated manner.

The collection of elements that accounts for approximately 98.5% of our body weight includes oxygen, hydrogen, carbon, phosphorus, nitrogen, and calcium. These elements are essential components of major biological molecules such as proteins, nucleic acids, carbohydrates, and lipids, which make up the majority of our body's mass. Oxygen is a major component of water and is crucial for cellular respiration, while hydrogen is also found in water and is involved in many biochemical reactions. Carbon is the backbone of organic molecules, while phosphorus is important for DNA, RNA, and energy transfer. Nitrogen is a key component of proteins and nucleic acids, and calcium plays a vital role in bone structure and muscle contraction.

Blood pressure in capillaries forcing water and dissolved solutes out into the tissue is an example of passive transport because it occurs through a physical process (filtration) without the need for energy. On the other hand, the uptake of LDL from the blood stream via receptor-mediated endocytosis is an example of active transport because it requires energy to transport molecules against their concentration gradient through the use of specific receptors.

The joining of 3 fatty acid molecules and a glycerol molecule, with the subsequent removal of 3 water molecules, forms a triglyceride. This process is an example of a dehydration synthesis reaction, as water molecules are removed during the formation of the triglyceride.

Semiconservative DNA replication is the process by which DNA is replicated during the S phase of the cell cycle. This is the phase in which DNA synthesis occurs, and each strand of the original DNA molecule serves as a template for the synthesis of a new complementary strand. The result is two daughter DNA molecules, each consisting of one original strand and one newly synthesized strand. Transcription, translation, posttranslational modification, and mitosis are not directly involved in DNA replication.

Free radicals are chemical compounds with an odd number of electrons that can be neutralized by antioxidants such as vitamin E.

Keratinized stratified squamous epithelium would be found in areas of the body that experience significant "wear and tear" because it provides protection against abrasions and penetration of pathogenic organisms. The keratinization process involves the accumulation of a tough, waterproof protein called keratin, which makes the epithelium resistant to mechanical stress and prevents the entry of microorganisms. This type of tissue is commonly found on the outer layer of the skin, such as the epidermis, as well as in other areas that are exposed to friction and potential injury, like the lining of the oral cavity and the esophagus.

Telomeres are repetitive nucleotide sequences located at the ends of chromosomes. Their primary function is to protect the chromosome's ends from deterioration and fusion with other chromosomes. This protective role is crucial during cell division, as it prevents the loss of essential genetic information from the chromosome's ends. Telomeres can shorten with each cell division, and this shortening is associated with aging and reduced cellular function.

The process of transcription involves the synthesis of mRNA using a DNA template. During transcription, the DNA sequence is transcribed into its complementary RNA sequence. In this case, the DNA nucleotide sequence TAGCAGCTT would be transcribed into the mRNA sequence AUCGUCGAA. Each DNA nucleotide is replaced by its complementary RNA nucleotide: T (thymine) is replaced by A (adenine), A (adenine) is replaced by U (uracil), G (guanine) is replaced by C (cytosine), and C (cytosine) is replaced by G (guanine). Therefore, the correct mRNA sequence is AUCGUCGAA.

Mitochondria are not directly involved in the common production and processing of proteins. They are responsible for generating energy in the form of ATP through cellular respiration. Protein production and processing primarily occur in the rough endoplasmic reticulum, ribosomes, and Golgi complex, where proteins are synthesized, modified, and transported. Therefore, mitochondria are the cellular component that is not involved in these processes.

The correct answer is "none of the above" because all of the options listed are known carcinogens. Human papilloma virus (HPV) is a risk factor for cervical cancer, cigarette tar contains numerous cancer-causing chemicals, ultraviolet rays from the sun can cause skin cancer, and industrial chemicals have been linked to various types of cancer. Therefore, none of the options listed are exceptions to being carcinogens.

The glycocalyx of the cell, composed of glycoproteins and glycolipids, is responsible for cell identification. It acts as a unique identifier for each cell, allowing the immune system to recognize self from non-self cells. This identification is crucial for various cellular processes, including cell signaling, cell adhesion, and cell-cell communication. The glycocalyx also plays a role in protecting the cell from mechanical and chemical damage.

Transcription is the process of synthesizing RNA from a DNA template, and it involves the enzyme RNA polymerase. Translation, on the other hand, is the process of converting the mRNA code into a sequence of amino acids to form a protein. This process occurs in ribosomes and requires tRNA molecules to carry specific amino acids. Therefore, the correct answer is RNA, mRNA, tRNA.

Gap junctions are membrane junctions that allow nutrients or ions to flow from cell to cell. Hemidesmosomes, on the other hand, anchor cells of the epithelium to the basement membrane.

Amino acids are organic compounds that serve as the building blocks of proteins. They are composed of four main components: an amino group, a carboxyl group, a central carbon atom, and a variable side chain known as the R group. These components are responsible for the unique properties and functions of each amino acid. However, a hydroxyl functional group, which consists of an oxygen atom bonded to a hydrogen atom and is commonly found in molecules such as alcohols, is not a component of amino acid structure.

Enzymes are catalysts, which means they speed up chemical reactions without being consumed in the process. They bind to specific molecules called substrates and lower the activation energy required for the reaction to occur. By lowering the activation energy, enzymes make it easier for the reaction to proceed, effectively decreasing the amount of energy needed for the reaction to happen.

The passage of solutes across the plasma membrane from a region of high concentration to one of lower concentration is called diffusion. In this process, solutes move down their concentration gradient, meaning they move from an area of higher concentration to an area of lower concentration. Crenation refers to the shrinking of cells due to water loss, osmosis is the movement of water across a selectively permeable membrane, hypertonicity refers to a solution with a higher solute concentration than another solution, and filtration refers to the movement of substances across a membrane due to pressure. None of these terms accurately describe the given process.

The correct answer is "membrane potential, muscular and nervous." The membrane potential refers to the electrical charge difference across the plasma membrane. This potential is responsible for the excitation of both muscular and nervous tissues.

During prophase of mitosis, the chromosomes condense and become visible under a microscope. This is the first stage of mitosis where the nuclear membrane breaks down and the spindle fibers start to form. On the other hand, during anaphase of mitosis, the sister chromatids of each chromosome separate and migrate towards opposite poles of the cell. This is facilitated by the contraction of the spindle fibers. Therefore, the correct answer is prophase, anaphase.

DNA ligase is the correct answer because it is an enzyme that plays a crucial role in DNA replication. It helps in joining the Okazaki fragments on the lagging strand during DNA synthesis. DNA ligase catalyzes the formation of phosphodiester bonds between the adjacent nucleotides, sealing the gaps and creating a continuous DNA strand. This enzyme is essential for the completion of DNA replication and the maintenance of the integrity of the genetic material.

The correct answer is simple columnar epithelium. This type of epithelium is found lining the GI tract and is covered by a "brush border" of microvilli. It specializes in absorption and secretion due to the presence of microvilli, which increase the surface area for these processes. Simple columnar epithelium is well-suited for the functions of absorption and secretion because it consists of a single layer of tall, closely packed cells that provide a barrier while allowing for efficient exchange of substances between the lumen of the GI tract and the underlying tissues.

The correct answer is both A and B. The nucleus of the cell is the largest organelle and it is also the site of mRNA synthesis. This means that it plays a crucial role in controlling the cell's activities and genetic information. The nucleus is surrounded by a single membrane called the nuclear envelope, which helps to protect and regulate the movement of molecules in and out of the nucleus. Therefore, both statements A and B are true, making the answer both A and B.

The difference between DNA and RNA is incorrect is "none of the above". This means that all of the differences mentioned in the options are correct. DNA and RNA differ in terms of their size, type of monosaccharide they have (DNA has deoxyribose while RNA has ribose), presence of thymine in DNA and uracil in RNA, and their structure (DNA is double stranded while RNA is single stranded).

The correct answer is histones, nucleosomes. Chromatin is the combination of DNA and proteins, and the proteins involved are called histones. These histones help in packaging and organizing the DNA into a more complex structure known as nucleosomes. Nucleosomes consist of DNA wrapped around a core of histone proteins, forming a bead-like structure. Therefore, histones and nucleosomes are the correct terms to describe the DNA-protein complexes involved in chromatin structure.

The correct hierarchy of complexity, from left to right, is:



atoms, molecules, organelles, cells



In this hierarchy:



- Atoms are the basic building blocks of matter.

- Molecules are formed when atoms bond together.

- Organelles are specialized structures within cells.

- Cells are the fundamental units of life.