Human Biology: Feedback Mechanisms and Acidosis

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Questions and Answers

What causes acidosis in the human body?

High levels of potassium

Increased oxygen intake

Excessive loss of acidic substances

Inability to excrete CO2 (correct)

Which of the following classifications describes organic compounds?

Compounds primarily made of inorganic salts

Compounds containing only oxygen

Compounds that do not include carbon

Compounds with carbon and hydrogen (correct)

What is the primary role of water in the living system?

To release energy from nutrients

To regulate blood sugar levels

To transport chemicals and absorb heat (correct)

To form carbonic acid

Which of the following is NOT a function of inorganic salts in the body?

Transporting oxygen (D) Signup and view all the answers

Which statement correctly describes carbon dioxide in metabolic processes?

It is produced as a waste product during metabolism. (B) Signup and view all the answers

Which of the following is not one of the basic components of a feedback control loop?

Transmitter (A) Signup and view all the answers

The contraction of the uterus during childbirth is an example of which type of feedback?

Positive feedback (A) Signup and view all the answers

What is a primary function of negative feedback mechanisms?

Stabilize changes in blood glucose levels (D) Signup and view all the answers

Which statement is true regarding negative feedback mechanisms?

They minimize deviations from a set point. (B) Signup and view all the answers

Which of the following is NOT a characteristic of negative feedback mechanisms?

Cause extreme fluctuations in conditions. (B) Signup and view all the answers

What ratio do carbohydrates typically contain carbon, hydrogen, and oxygen?

1:1:2 (B) Signup and view all the answers

What type of linkage is formed when two sugar molecules combine?

Glycosidic linkage (A) Signup and view all the answers

Which of the following is NOT a function of sugars?

Acting as enzymes (A) Signup and view all the answers

What are the principal building blocks of protein in humans?

Amino acids (C) Signup and view all the answers

Which element is commonly found in amino acids but not in carbohydrates?

Nitrogen (B) Signup and view all the answers

What type of compound is adenosine triphosphate (ATP)?

A high-energy compound (C) Signup and view all the answers

Which of the following describes polysaccharides?

Long chains of many monosaccharides (D) Signup and view all the answers

Which aspect of proteins distinguishes them from other biological molecules?

They are composed of amino acids (D) Signup and view all the answers

What property of water is primarily determined by hydrogen bonds?

Three-dimensional structure of large molecules (B) Signup and view all the answers

Which of the following is classified as an electrolyte?

Sodium chloride (A) Signup and view all the answers

What is the function of electrolytes in the body?

To exert osmotic pressure and assist in muscle contraction (B) Signup and view all the answers

Which of the following statements about acids and bases is true?

Bases accept hydrogen ions and may release hydrogen ions. (A) Signup and view all the answers

What is the pH level of a neutral solution?

7 (B) Signup and view all the answers

In a neutralization reaction, what do the hydrogen ions from an acid react with?

Hydroxide ions from a base (B) Signup and view all the answers

Which of the following substances does NOT act as an electrolyte when dissolved in water?

Sucrose (D) Signup and view all the answers

Why is maintaining pH levels in body fluids important?

To maintain a stable internal environment and proper biochemical reactions (A) Signup and view all the answers

What role do enzymes play in chemical reactions?

They lower the activation energy required. (B) Signup and view all the answers

Which of the following factors can influence enzyme activity?

Presence of a cofactor (B) Signup and view all the answers

How do enzymes assist in anabolic reactions?

By combining multiple substrates into larger products. (D) Signup and view all the answers

What happens to the active site of an enzyme after the reaction is complete?

It becomes available for another substrate. (B) Signup and view all the answers

In what kind of reaction do enzymes act to break down substrates?

Catabolic reaction (A) Signup and view all the answers

Which of the following best describes activation energy?

Energy required to initiate chemical reactions. (C) Signup and view all the answers

What primarily determines the function of a protein?

The 3-dimensional shape of the protein (C) Signup and view all the answers

Which statement about isotopes is true?

Isotopes have the same atomic number but different atomic weights. (D) Signup and view all the answers

Homeostasis can best be described as:

A state of relative constancy. (B) Signup and view all the answers

Which of the following is NOT a characteristic of proteins?

Solid structure at room temperature (B) Signup and view all the answers

Which of the following is a function of fats?

Insulate the body and protect internal organs (A) Signup and view all the answers

What type of lipids are triglycerides classified as?

Saturated or unsaturated fats (B) Signup and view all the answers

Which of the following structures is integral to the cell membrane?

Phospholipids (C) Signup and view all the answers

Which component makes up a nucleotide?

A sugar, a base, and a phosphate group (B) Signup and view all the answers

What is the primary function of adenosine triphosphate (ATP)?

Serve as the energy currency of the body (A) Signup and view all the answers

What is one role of cholesterol in the body?

It stabilizes cell membranes (D) Signup and view all the answers

Study Notes

Introduction to Anatomy and Physiology 1: Chemistry of the Human Body (Part 2)

Students will be able to define atoms, molecules, and compounds;
describe atomic structure;
discuss molecular bonds;
define molar concentration;
and explain the importance of buffers in pH regulation.

Atoms, Molecules, and Compounds

Atoms are the smallest unit of an element that can exist as a stable entity.
An element contains only atoms of the same type (e.g., iron contains only iron atoms).
Compounds contain more than one type of atom (e.g., water contains hydrogen and oxygen atoms).
Matter is anything that occupies space and has mass.
Mass is the amount of matter in an object.
Weight is the force exerted by Earth's gravity on matter.

Atomic Structure

Atoms are mostly empty space with a tiny central nucleus containing protons and neutrons, surrounded by orbiting electrons.
Atoms consist of protons, neutrons, and electrons.
Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.
Protons and neutrons are located in the nucleus.
Electrons are located around the nucleus and can be represented by an electron cloud.
The mass of electrons is negligible compared to protons and neutrons.
Neutrons and protons each have a mass of one atomic mass unit.

Atomic Structure (Continued)

Atomic number is the unique number of protons in an atom.
Mass number is the sum of protons and neutrons in an atom.
Isotopes are atoms that have the same atomic number but different mass numbers (e.g., different numbers of neutrons).
Atomic mass is the average mass of naturally occurring isotopes, weighted according to their abundance.
A mole of a substance contains Avogadro's number (6.022 x 10²³) of atoms, ions, or molecules.
The molar mass of a substance is the mass of one mole of that substance in grams.

Mass Number and Atomic Number

Example: If an atom has 17 protons and 18 neutrons:
- Mass number = 17 + 18 = 35
- Atomic number = 17

Molecules and Compounds

A molecule is two or more atoms chemically combined to form a structure that behaves as an independent unit.
A compound is two or more different types of atoms chemically combined.
The kinds and numbers of atoms (or ions) in a molecule or compound can be represented by a formula consisting of the symbols of the atoms (or ions) plus subscripts denoting the number of each type of atom (or ion).
The molecular mass of a molecule or compound can be determined by adding up the atomic masses of its atoms (or ions).
Example: NaCl - the atomic mass of sodium (Na) is 22.99, and the atomic mass of chlorine(Cl) is 35.45. The molecular mass of NaCl is therefore: 22.99 + 35.45= 58.44

Types of Bonds

A chemical bond occurs when atoms share or transfer electrons.
Ionic bonds- Atoms transfer electrons.
Covalent bonds- Atoms share electrons. - Nonpolar covalent bond – Occurs when electron pairs are equally shared between atoms. - Polar covalent bond – Occurs when electron sharing between atoms is unequal, resulting in a polar molecule.
Hydrogen bonds – Weak attraction between a positively charged hydrogen and a negatively charged oxygen or other polar molecule (e.g., in water).

Molecules and Compounds (Solubility & Electrolytes)

Solubility is the ability of one substance to dissolve in another.
Ionic compounds that dissolve in water via dissociation are called electrolytes because they can conduct electricity.
Electrolytes are important because they conduct electricity (essential for muscle and nerve function), their ions exert osmotic pressure (keeping body fluids in compartments), and they are essential in acid-base balance (resisting pH changes in the body).
Molecules that do not dissociate are nonelectrolytes.

Molecules and Compound (Other electrolytes)

Important electrolytes in the body include:
- Potassium (K+)
- Calcium (Ca2+)
- Bicarbonate (HCO3−)
- Phosphate (PO43−),
These substances play roles in many metabolic processes, including nerve impulse transmission, muscle contraction, acid-base balance, and other cellular functions.

Acids, Bases, and pH

Acidity of a solution is determined by the number of hydrogen ions (H+) in the solution.
A base accepts hydrogen ions often resulting in the release of hydroxyl ions (OH−).
A salt releases other anions and cations when dissolved. Sodium chloride (NaCl) is an example of a salt with both a positive and negative ion.
pH is a scale to measure the concentration of hydrogen ions. The pH scale measures from 0 to 14, with 7 being neutral.

Buffers

Buffering mechanisms are important for homeostasis (maintaining stable internal environment) by neutralizing fluctuations in pH temporarily.
The lungs and kidneys are the most active organs in pH regulation.
Lungs regulate blood pH by excreting carbon dioxide (CO2).
CO2 reacts with water to form carbonic acid, which then dissociates into a bicarbonate ion and hydrogen ion, maintaining proper pH levels.
Kidneys regulate blood pH by adjusting the excretion of hydrogen and bicarbonate ions; and they generate additional bicarbonate ions. This process also generates ammonium ions, which are rapidly excreted.
Buffer systems (compounds) in body fluids, like haemoglobin and phosphate, moderate pH changes in cells.

Common Substances in Living Systems

Nutrients are essential chemical compounds obtained from the diet.
Metabolites are synthesized or broken down inside the body.
Nutrients and metabolites are classified as either organic or inorganic.
Inorganic substances in cells include water, oxygen, carbon dioxide, and inorganic salts.
Water is essential for metabolic reactions and is an important transport medium.
Oxygen is used to release energy from nutrients in cells.
Carbon dioxide is produced as a waste product in metabolic reactions.
Inorganic salts are crucial for various body functions.

Organic Substances

Organic compounds are primarily made up of carbon and hydrogen.
Important classes of organic compounds in living systems include carbohydrates, lipids, proteins, nucleic acids, and high-energy compounds like ATP.

Learning Outcomes

Students will be able to describe the chemical nature of sugars, proteins, lipids, nucleotides, and enzymes.
Students will be able to discuss the biological importance of each of these important groups of molecules.

Chemical Reactions

A chemical reaction involves atoms or molecules interacting to form new combinations.
Reactants are present before the reaction and products result from the reaction.
Decomposition is the breaking down of complex reactants into simpler products.
Hydrolysis involves using water to break down bonds.
Metabolism is the sum of all reactions occurring in the body — catabolic (break down) and anabolic (synthesis).

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Description

This quiz covers key concepts in human biology, including acidosis, the roles of organic and inorganic compounds, water's function in living systems, and feedback mechanisms. Test your understanding of these fundamental topics and their applications in the human body.