Anatomy and Physiology I with Lab (D312)

Correct Answer

C. Binds with molecules or ions to move them across the cell membrane

Explanation

Transporter (carrier) proteins bind to specific molecules or ions and move them across the cell membrane. This can occur through active transport (requiring energy) or facilitated diffusion (no energy required). These proteins are essential for maintaining cellular functions by regulating the intake of nutrients, ions, and the removal of waste products.

Why other options are wrong

A. Attaches to molecules to anchor them to the cell membrane. This does not describe the primary function of a transporter protein, which is to move molecules, not just anchor them.

B. Catalyzes a chemical reaction. Transporter proteins are not enzymes and do not catalyze chemical reactions; they facilitate the movement of substances across the membrane.

D. Permits diffusion of solutes through a membrane. While some transporter proteins assist in facilitated diffusion, this answer doesn't fully capture the active role of transporter proteins, which can also move molecules against their concentration gradient (active transport).

E. Bind with specific molecules to initiate a response of a cell. This describes a receptor protein, not a transporter protein. Receptor proteins initiate cellular responses, whereas transporter proteins are involved in transporting molecules.

Correct Answer

D. Fewer electrons than protons

Explanation

A cation is an atom or molecule that has lost one or more electrons, giving it a positive charge. Since protons are positively charged and electrons are negatively charged, losing electrons results in a positive charge. Therefore, a cation has fewer electrons than protons.

Why other options are wrong

A. More electrons than protons

This is incorrect because if there were more electrons than protons, the atom would have a negative charge (an anion), not a positive charge.

B. More electrons than neutrons

This is not a defining feature of a cation. Neutrons do not affect the charge of an atom directly, and the number of electrons compared to neutrons does not necessarily determine whether an atom is a cation.

C. Fewer electrons than neutrons

This is incorrect because the number of neutrons does not determine the charge of the atom. A cation has fewer electrons than protons, not necessarily fewer electrons than neutrons.

Correct Answer

B. Contribute to atomic mass

Explanation

Neutrons are neutral particles located in the nucleus of an atom. They have no charge and contribute to the atomic mass of an element along with protons. The number of neutrons in an atom can vary, leading to different isotopes of an element. Neutrons do not affect the atomic number, which is determined by the number of protons.

Why other options are wrong

A. Revolve around the nucleus

This is incorrect because electrons revolve around the nucleus, not neutrons. Neutrons are located in the nucleus and do not orbit the nucleus.

C. Are positively charged

This is incorrect because neutrons have no charge; they are neutral. It is the protons that are positively charged.

D. Determine atomic number

This is incorrect because the atomic number is determined by the number of protons in the nucleus, not neutrons.

Correct Answer

B. It initiates a response that counteracts the initial change to stabilize the system.

Explanation

A negative feedback mechanism is a process in which the body detects a change in a physiological variable and activates a response that counteracts or negates the initial change, bringing the system back to its normal state or homeostasis. This is essential for maintaining stable internal conditions such as body temperature, blood pressure, and pH. For example, if body temperature rises above normal, mechanisms like sweating are activated to cool the body down.

Why other options are wrong

A. It amplifies the original stimulus to enhance the response.

This is incorrect because this describes positive feedback, not negative feedback. In positive feedback, the response amplifies the initial change, which is not the case in negative feedback mechanisms.

C. It has no effect on the physiological processes of the body.

This is incorrect because negative feedback mechanisms are critical for regulating physiological processes and maintaining homeostasis.

D. It creates a new equilibrium by introducing additional stimuli.

This is incorrect because negative feedback does not create new equilibria by adding stimuli. It works to return the system to its original equilibrium by counteracting changes.

Correct Answer

A. Weakened immune system

Explanation

The research by Richard and Mulenga (2019) suggests that poor sleep quality can significantly impact various aspects of health, with one of the primary consequences being a weakened immune system. Inadequate sleep disrupts the normal functioning of immune cells, making the body more susceptible to infections and illnesses.

Why other options are wrong

B. Improved memory retention. Poor sleep quality typically impairs memory retention rather than improving it. Sleep is crucial for consolidating memories, and disruptions can negatively affect cognitive functions.

C. Enhanced concentration. Poor sleep quality reduces concentration and attention span. Inadequate rest can lead to difficulty focusing on tasks and retaining information.

D. Increased energy levels. Poor sleep quality generally leads to fatigue and low energy levels, not an increase. The body needs restorative sleep to maintain high energy throughout the day.

Correct Answer

C. Facilitating glucose uptake into cells

Explanation

After a meal, insulin is released by the pancreas in response to increased blood glucose levels. Its primary role is to facilitate the uptake of glucose into cells, particularly muscle and fat cells, where it is either used for energy or stored as glycogen. This process helps lower blood sugar levels back to normal after eating.

Why other options are wrong

A. Stimulating testosterone production. Insulin does not stimulate testosterone production. Testosterone is regulated by the testes in males and ovaries in females, and it is not influenced by insulin in this context.

B. Inhibiting estrogen secretion. Insulin does not have a role in inhibiting estrogen secretion. Estrogen is regulated by the ovaries, and its secretion is influenced by hormonal signals, not by insulin.

D. Increasing blood sugar levels. This is incorrect because insulin actually works to lower blood sugar levels. It facilitates the uptake of glucose into cells, reducing the amount of glucose in the bloodstream.

Correct Answer

C. Cushions brain and spinal cord, provides nutrients, removes waste; ventricles of brain, subarachnoid space

Explanation

Cerebrospinal fluid (CSF) is a clear, colorless fluid that cushions the brain and spinal cord, providing protection from mechanical injury. It also delivers nutrients to the brain and removes waste products from the central nervous system. CSF is located in the ventricles of the brain and the subarachnoid space surrounding the brain and spinal cord.

Why other options are wrong

A. Filters blood, produces hormones, located in the endocrine glands

This is incorrect because cerebrospinal fluid does not filter blood or produce hormones. These functions are performed by the kidneys and endocrine glands, not CSF.

B. Regulates body temperature, aids digestion, located in the stomach

Cerebrospinal fluid does not regulate body temperature or aid digestion. These functions are associated with the hypothalamus and digestive system, not CSF.

D. Controls muscle movement, supports bone structure, located in the muscles

This is incorrect because cerebrospinal fluid does not control muscle movement or support bone structure. These are functions of the nervous system and musculoskeletal system, not CSF.

Correct Answer

C. Peptide bonds

Explanation

Peptide bonds are covalent bonds that form between amino acids during protein synthesis. This bond occurs through a dehydration reaction, where a molecule of water is removed as the carboxyl group of one amino acid reacts with the amino group of another. Peptide bonds create long chains of amino acids, known as polypeptides, which fold into functional proteins. The strength and stability of peptide bonds allow proteins to maintain their structure and perform essential biological functions.

Why other options are wrong

A. Hydrogen bonds

Hydrogen bonds help stabilize secondary, tertiary, and quaternary structures of proteins, but they do not link amino acids together. Instead, they contribute to the formation of structures like alpha-helices and beta-sheets within proteins.

B. Ionic bonds

Ionic bonds can form between charged side chains (R-groups) of amino acids, contributing to protein stability, but they do not create the primary structure of proteins like peptide bonds do.

D. Disulfide bonds

Disulfide bonds form between cysteine residues in a protein, helping to stabilize tertiary and quaternary structures. They play an important role in maintaining protein shape but are not responsible for linking amino acids during protein formation.

Correct Answer

B. Questionnaire

Explanation

Richard and Mulenga (2019) used questionnaires as their primary data collection method. The questionnaire allowed them to gather responses from participants regarding their energy drink consumption and sleep quality in a standardized format, making it easier to analyze the relationship between the two.

Why other options are wrong

A. Observational study. An observational study involves watching participants in their natural environment without interacting with them, which was not the method used in this research.

C. Interviews. Interviews involve one-on-one discussions, but Richard and Mulenga (2019) specifically used questionnaires to collect data from a larger sample efficiently.

D. Focus groups. Focus groups involve group discussions, but the study did not rely on this method. Instead, questionnaires were used to gather individual responses from participants.