Comprehensive Physiology: Atoms, Bonds, Water, Organic Molecules, and Cell Structures

What is an atom?

The smallest unit of any substance or element.

What particles are found in the nucleus of an atom?

Positively charged protons and uncharged neutrons.

What is the atomic mass of an atom?

The sum of protons and neutrons.

What does the atomic number represent?

The number of protons in an atom.

What are electron orbitals?

Distinct energy levels that surround the nucleus of an atom.

How many electrons can the first orbital hold?

A maximum of 2 electrons.

How many electrons can the second orbital hold?

A maximum of 8 electrons.

What are valence electrons?

Electrons located in unfilled outer shells that participate in chemical bonding.

What type of bond is formed by sharing electrons?

Covalent bonds.

What are nonpolar covalent bonds?

Bonds where electrons are shared equally.

What are polar covalent bonds?

Bonds where electrons are not shared equally, resulting in distinct positive and negative ends.

What is an ionic bond?

A bond formed by the complete transfer of one or more electrons from one atom to another.

What is a cation?

An electron donor that becomes positively charged.

What is an anion?

An electron receiver that becomes negatively charged.

What happens to ionic compounds in water?

They dissociate into their respective ions.

What is the pH scale?

A logarithmic scale from 0 to 14 that measures the acidity or alkalinity of a solution.

What is a neutral pH value?

A pH of 7, indicating equal concentrations of hydrogen and hydroxide ions.

What is acidosis?

A condition where blood pH is under 7.35.

What is alkalosis?

A condition where blood pH is over 7.45.

What are buffers?

Solutions that resist changes in pH.

What is a monosaccharide?

A simple sugar with one carbon ring, such as glucose or fructose.

What is a disaccharide?

Two monosaccharides joined by a covalent bond.

What is the significance of functional groups in organic molecules?

They allow organic compounds to be classified and give them unique chemical properties.

What is the general formula for carbohydrates?

Typically in the ratio of 1:2:1 for carbon, hydrogen, and oxygen.

What is a polysaccharide?

A polysaccharide is a carbohydrate composed of several monosaccharides joined together, usually glucose.

What is starch and its function?

Starch is the storage form of sugar in plants, consisting of thousands of glucose molecules.

What is glycogen and its role in animals?

Glycogen is the storage form of sugar in animals and does not exert the same osmotic pressure as simple sugars.

What is cellulose and why can't humans digest it?

Cellulose forms the cell walls of plants and is not digestible by humans due to a lack of necessary enzymes.

What is dehydration synthesis?

Dehydration synthesis is a process that forms covalent bonds by removing a hydrogen atom from one molecule and a hydroxyl group from another, releasing a molecule of water.

What is hydrolysis?

Hydrolysis is the process of breaking bonds between monosaccharides by adding a molecule of water to split a larger molecule.

What are lipids and their general characteristics?

Lipids are hydrophobic molecules consisting of nonpolar hydrocarbon chains and rings.

What are triglycerides?

Triglycerides are fats and oils composed of one glycerol molecule and three fatty acid molecules.

What distinguishes saturated fats from unsaturated fats?

Saturated fats have every carbon in the fatty acid chain connected by single bonds, while unsaturated fats have one or more double bonds between carbons.

What are ketone bodies and how are they formed?

Ketone bodies are formed from the hydrolysis of triglycerides, releasing free fatty acids into the blood, which can be used for energy or converted by the liver.

What is ketosis?

Ketosis is a condition characterized by elevated ketone levels, often resulting from strict low-carb diets or uncontrolled diabetes.

What is ketoacidosis?

Ketoacidosis is a dangerous condition where high ketone levels lower blood pH, potentially leading to coma or death.

What are phospholipids and their role in cell membranes?

Phospholipids are lipids that include a phosphate group, making them polar; they form a double layer in cell membranes.

What is the structure of steroids?

Steroids are characterized by a structure of three 6-carbon rings and one 5-carbon ring.

What is cholesterol's role in the body?

Cholesterol acts as a precursor to steroid hormones like testosterone and estrogen and is used to synthesize essential molecules like vitamin D and bile salts.

What are prostaglandins?

Prostaglandins are fatty acids containing a cyclic hydrocarbon group that function as communication molecules between cells.

What are the major functions of proteins?

Proteins provide structural support, catalyze chemical processes, form antibodies, receive signals, and transport substances.

What is the basic structure of an amino acid?

Each amino acid has an amino group, a carboxyl group, and a unique functional (R) group.

What are the four levels of protein structure?

The four levels are primary (amino acid sequence), secondary (local folding), tertiary (overall 3D shape), and quaternary (arrangement of multiple polypeptide chains).

What is protein denaturation?

Denaturation is the process where changes in pH or temperature break weak bonds in a protein, causing it to unfold and lose function.

What are conjugated proteins?

Conjugated proteins are proteins that must combine with non-protein molecules to become functional, such as glycoproteins and lipoproteins.

What are nucleic acids and their building blocks?

Nucleic acids are molecules of heredity made up of nucleotides, which consist of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

What are the two categories of nitrogenous bases?

Nitrogenous bases are categorized into pyrimidines (single ring) and purines (double ring).

What is the structure of DNA?

DNA is a double helix formed by a sugar-phosphate backbone and nitrogenous bases that pair specifically (A-T, C-G) through hydrogen bonds.

What is the law of complementary base pairing?

The law states that nitrogenous bases pair in a specific manner essential for DNA replication and transcription.

What are the differences between DNA and RNA?

RNA contains ribose sugar, is single-stranded, and has uracil instead of thymine.

What are the types of RNA and their functions?

mRNA carries genetic information from DNA to the cytoplasm, tRNA transfers amino acids during protein synthesis, and rRNA is a component of ribosomes.

What are ATP and GTP?

ATP (adenosine triphosphate) and GTP (guanosine triphosphate) are primary energy carriers in cells.

What are NAD and FAD?

NAD (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) are vital coenzymes in cellular respiration.