Bio 208 Exam I

A cell is the smallest living functional unit because it is the basic structural and functional unit of all living organisms. Cells are responsible for carrying out all the necessary processes of life, such as metabolism, reproduction, and response to stimuli. They are capable of independent existence and can perform all the functions required for survival.

Carbohydrates are organic compounds that consist of carbon, hydrogen, and oxygen atoms in a near 1:2:1 ratio. They are one of the major macronutrients and serve as a primary source of energy for living organisms. Carbohydrates can be found in various forms such as sugars, starches, and fibers. Proteins, lipids, and steroidal compounds do not have the same 1:2:1 ratio of carbon, hydrogen, and oxygen atoms, so they are not the correct answer in this case. Therefore, the correct answer is carbohydrate.

A substance with a pH less than 7 indicates that it is acidic. Acidity is determined by the concentration of hydrogen ions in a solution, and a pH value below 7 signifies a higher concentration of hydrogen ions. Therefore, the correct answer is acidic.

Sebaceous glands are the glands that discharge an oily secretion into the hair follicles. This oily secretion, known as sebum, helps to lubricate the skin and hair, preventing them 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 particularly abundant on the face, scalp, and upper back. The sebum produced by sebaceous glands can sometimes lead to clogged pores and acne if it becomes excessive or if there is an imbalance in its production.

The correct answer is "ALL of the above". Melanoma is a type of cancer that originates from melanocytes, which are the cells responsible for producing melanin. It is considered the fastest growing cancer in the US and has a higher risk of developing in sunburned or UV-exposed skin. Additionally, melanoma is known to be the most deadly form of skin cancer. Therefore, all of the statements provided are true about melanoma.

Anions are ions that carry a negative charge. They are formed when an atom gains one or more electrons. This extra electron(s) gives the ion a negative charge, hence the name "anion." Anions play a crucial role in chemical reactions and are often involved in the formation of compounds. They are represented with a negative sign (-) next to the chemical symbol.

A tight junction is a type of intercellular connection where the outermost lipid portions of the two cell membranes are fused. This fusion creates a barrier that prevents the movement of molecules between the cells, making the junction "tight." This type of junction is commonly found in epithelial tissues, such as the lining of the digestive tract, where it helps maintain the integrity and selective permeability of the tissue. Gap junctions, desmosomes, and intermediate junctions are different types of intercellular connections that serve different functions in cell communication and adhesion. Therefore, the correct answer is tight junction.

The correct sequence is DNA-mRNA-tRNA-protein. This is the correct order of molecular processes involved in protein synthesis. DNA is transcribed into mRNA, which is then translated into a protein with the help of tRNA.

In physiology, the function of a body part or system is closely related to its structure. The structure refers to the specific arrangement and organization of the tissues, cells, and organs that make up the body part or system. The structure determines how the body part or system is able to carry out its specific function. For example, the structure of the heart, with its chambers, valves, and blood vessels, allows it to pump and circulate blood throughout the body. Therefore, understanding the structure of a body part or system is essential in understanding its function.

Transitional epithelium is a type of tissue that is capable of stretching and expanding. It is specifically designed to line organs that need to accommodate changes in volume, such as the urinary bladder. The urinary bladder is a hollow organ that expands as it fills with urine and contracts to expel it. The presence of transitional epithelium in the lining of the urinary bladder allows it to stretch and accommodate the varying volume of urine. Therefore, the correct answer is lining the urinary bladder.

A fatty acid that contains three double covalent bonds in its carbon chain is classified as polyunsaturated. This means that there are multiple unsaturated bonds (double bonds) present in the fatty acid molecule. The term "poly" indicates that there are more than one unsaturated bond, while "unsaturated" refers to the presence of double bonds. Therefore, polyunsaturated fatty acids have multiple double bonds in their carbon chain.

Negative feedback is essential for all homeostatic processes because it helps maintain stability and balance in the body. Negative feedback occurs when a change in a regulated variable triggers a response that opposes the change and brings the variable back to its set point. This allows the body to constantly monitor and adjust its internal conditions to keep them within a narrow range. Positive feedback, on the other hand, amplifies the initial change and does not contribute to homeostasis. Therefore, the best description for all homeostatic processes is that negative feedback is essential.

The correct answer is basale (germinativum). The stratum basale, also known as the stratum germinativum, is the deepest layer of the epidermis. It is responsible for cell division and renewal, as it contains actively dividing cells. These cells then migrate towards the upper layers of the epidermis, undergoing differentiation and eventually becoming the outermost layer of the skin. The other options, such as spinosum, lucidem, granulosum, and corneum, are also layers of the epidermis, but they do not specifically contain cells undergoing division.

Fibrous connective tissue is a type of connective tissue that is characterized by its dense arrangement of collagen fibers. Ligaments and tendons are examples of fibrous connective tissue because they are composed mainly of collagen fibers that provide strength and support to the joints and muscles. Salivary glands and respiratory passages are not examples of fibrous connective tissue as they are composed of different types of tissues such as glandular and epithelial tissues. Therefore, the correct answer is "both B and D" because ligaments and tendons are examples of fibrous connective tissue.

When Na+ is moved across the cell membrane against the concentration gradient, cellular ATP is used. This is because moving ions against their concentration gradient requires energy, which is provided by ATP. Osmosis refers to the movement of water across a membrane, and diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration. Vesicles are used for transporting larger molecules or substances across the cell membrane. However, in this case, the correct answer is specifically referring to the use of cellular ATP for the active transport of Na+ ions.

The cell membrane acts as a selective barrier that regulates the movement of substances in and out of the cell. It controls the exchange of materials with the environment and separates the cytoplasm from the extracellular solution. However, controlling movements into the nucleus is not a function of the cell membrane. The nucleus is surrounded by a separate membrane called the nuclear envelope, which controls the movement of molecules into and out of the nucleus.

The skin interacts with all of the above systems. The skeletal system provides support and protection for the skin. The urinary system helps regulate body temperature by controlling sweat production. The nervous system allows the skin to sense touch, pain, and temperature. The respiratory system supplies oxygen to the skin cells. Therefore, the skin interacts with all of these systems.

Collagen is a fibrous protein that provides strength and flexibility to various parts of the body. It forms bundles of fibrous proteins that are bound together like a rope, making it strong when pulled from the ends. The number and arrangement of collagen fibers contribute to its overall strength. Additionally, collagen is known for its flexibility. However, collagen does not possess the characteristic of being branched, wavy, and having great recoil.

Inside the cell, the concentration of sodium ions (Na+) is lower compared to the outside of the cell. This is because the cell actively pumps out sodium ions to maintain a lower concentration inside. This process is vital for various cell functions, such as maintaining osmotic balance and generating electrical impulses.

If two equal volumes of water are separated by a normal window screen, the screen will prevent the sugar from moving from one side to the other. Therefore, the sugar added to Volume A a week before will remain in Volume A and not mix with Volume B. As a result, both sides will have the same amount of sugar and water.

Muscle cells are not considered a type of cell in connective tissue. Connective tissue is primarily composed of cells such as fibroblasts, mast cells, mesenchymal cells, and macrophages. Muscle cells, on the other hand, are part of the muscular tissue, which is a distinct type of tissue responsible for movement. Therefore, muscle cells do not belong to the category of cell types found in connective tissue.

The shaft of a long bone is most closely associated with the diaphysis. The diaphysis refers to the long, cylindrical middle portion of a long bone, which contains the compact bone tissue. It is responsible for providing support and strength to the bone. The diaphysis also contains the medullary cavity, which houses the bone marrow. The epiphysis refers to the rounded ends of a long bone, while the periosteum is the outer covering of the bone. Endochondrial and appositional are processes involved in bone growth and development.

The question asks for the type of multicellular membranes that is NOT included in the given options. Among the options provided, "lymphoidal" is the only one that does not represent a type of multicellular membrane. "Synovial," "cutaneous," "mucous," and "serous" are all types of multicellular membranes found in the human body. Therefore, "lymphoidal" is the correct answer as it is not a type of multicellular membrane.

Appositional growth in bones refers to the increase in bone diameter. This type of growth occurs when new bone tissue is added to the outer surface of the existing bone, resulting in an increase in its diameter. This process is regulated by osteoblasts, which deposit new bone tissue, and osteoclasts, which remove old bone tissue. While bone length is also related to growth, it is primarily influenced by epiphyseal conversion, where the growth plates at the ends of long bones close and stop producing new bone tissue. Bone turnover, on the other hand, refers to the continuous process of bone resorption and formation.

Enzymes have specific optimal ranges because they are highly sensitive to changes in temperature, pH, and substrate concentration. These optimal ranges provide the most favorable conditions for the enzyme to catalyze a reaction efficiently. If the conditions deviate too much from the optimal range, the enzyme's activity can decrease or completely cease. Therefore, maintaining the specific optimal ranges is crucial for the proper functioning of enzymes.

When the epiphyseal plate is replaced by bone, it means that the growth plate in long bones has closed, indicating that the bones have reached their adult length. The epiphyseal plate is responsible for bone growth during childhood and adolescence, and its closure signifies the end of longitudinal bone growth. Therefore, the correct answer is that long bones have reached their adult length.

The correct answer is basale (germinativum) because this layer of the epidermis is responsible for the production of melanocytes, which are the cells that produce melanin, the pigment responsible for skin color. The stratum basale is also known as the stratum germinativum because it is the layer where new skin cells are formed through cell division.

Osteoclasts are large, multinucleated cells that are responsible for breaking down and dissolving the bony matrix. They play a crucial role in bone remodeling and resorption, allowing for the removal of old or damaged bone tissue. Osteoclasts secrete enzymes and acids that break down the mineralized matrix, making it possible for new bone to be formed by osteoblasts.

The papillary layer in the dermis is the correct answer. This layer of the skin contains the blood vessels and nerves that supply the surface of the skin. It is located just beneath the epidermis and is responsible for providing nutrients and oxygen to the outer layers of the skin.

Phosphorus (P) is the least common element that makes up proteins. Proteins are primarily composed of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), with small amounts of other elements like sulfur (S) and phosphorus (P) present in some proteins. However, phosphorus is found in proteins in very small quantities compared to the other elements listed. Therefore, P is the least common element in proteins.

Calcitonin is a hormone released by the thyroid gland that helps to regulate calcium levels in the blood. It works by decreasing the concentration of calcium in the blood, primarily by inhibiting the activity of osteoclasts, cells that break down bone tissue and release calcium into the blood. Therefore, calcitonin is the correct answer as it directly decreases the concentration of calcium in the blood.

Effector and control receptor are the two components that underlie how homeostasis works. The effector is responsible for making the necessary adjustments in response to changes in the internal or external environment, while the control receptor detects these changes and sends signals to the effector to initiate the appropriate response. This feedback loop between the effector and control receptor allows the body to maintain a stable internal environment, ensuring that physiological processes are functioning optimally.

Calcitonin is a hormone that is released by the thyroid gland and it plays a role in regulating calcium levels in the body. One of its main functions is to increase the rate of bone deposition. This means that it helps in the formation and building of new bone tissue. Therefore, the correct answer is "increase the rate of bone deposition".