Anatomy & Physiology Unit 2 Study Guide Part 1

Vocabulary flashcards covering chemistry, biological molecules, cell theory, cellular organelles, and transport mechanisms based on the Anatomy & Physiology Unit 2 Study Guide.

Matter

Anything that has mass and takes up space. Examples include blood, bones, and water.

Physical change

A change in size, shape, or state that does not change a substance’s chemical identity. Example: physically breaking food into smaller pieces while chewing.

Chemical change

A change that produces new substances through the rearrangement of atoms. Example: enzymes breaking down food molecules during digestion.

Law of conservation of mass

Matter cannot be created or destroyed during a chemical reaction. In a closed system, the total mass before and after the reaction is the same. Our balloon lab was an example.

Atomic number

The number of protons in an atom’s nucleus. It identifies the element.

Mass number

The total number of protons and neutrons in an atom’s nucleus.

Isotope

An atom of an element that has the same number of protons but a different number of neutrons than another atom of that element. Isotopes have different mass numbers.

Organic compound

A carbon-based compound that typically contains carbon–hydrogen bonds. Examples include carbohydrates, lipids, proteins, and nucleic acids.

Inorganic compound

A compound generally lacking carbon–hydrogen bonds. Examples include water, salts, and carbon dioxide. Some inorganic compounds contain carbon.

Electrolyte

A substance that produces ions when dissolved in water, allowing the solution to conduct electricity. Sodium, potassium, and calcium ions help support nerve and muscle function.

Acid

A substance that increases the concentration of hydrogen ions ($H^+$) in a solution. Acidic solutions have a pH below 7.

Base

A substance that accepts hydrogen ions or increases hydroxide ions ($OH^-$) in a solution. Basic solutions have a pH above 7. Our blood is slightly basic.

Carbohydrate

An organic molecule made of sugar units. Carbohydrates provide energy and can store energy. Examples include glucose and glycogen.

Triglyceride

A lipid made of one glycerol molecule and three fatty acids. It stores energy, helps insulate the body, and cushions organs.

Phospholipid

A lipid with a water-attracting head and two water-repelling fatty acid tails. Phospholipids form the bilayer of the plasma membrane.

Protein

A molecule made of amino acids linked together. Proteins provide structure and perform functions such as transport, movement, signaling, and speeding up chemical reactions.

Enzyme

A biological catalyst, usually a protein, that speeds up a chemical reaction by lowering its activation energy. It is not used up in the reaction.

Active site

The region of an enzyme where its substrate binds and the reaction occurs.

Denaturation

A change in a protein’s normal shape that can cause it to lose its function. High temperatures or extreme pH can cause denaturation.

DNA

Deoxyribonucleic acid; the molecule that stores genetic information, including instructions for making proteins.

mRNA

Messenger RNA; a copy of genetic instructions that carries information from DNA to a ribosome for protein production.

ATP

Adenosine triphosphate; a molecule that supplies usable energy for cellular work, such as active transport and muscle contraction.

Cell theory

All living things are made of one or more cells; the cell is the basic unit of structure and function in living things; and all cells come from preexisting cells.

Cell specialization

The process through which cells develop structures and functions suited to particular jobs. For example, nerve cells transmit signals, while muscle cells contract.

Plasma membrane

The selectively permeable boundary of a cell. It consists mainly of a phospholipid bilayer and proteins and controls what enters and leaves the cell.

Chromatin

DNA and associated proteins found in the nucleus. Chromatin condenses into visible chromosomes during cell division.

Mitochondrion

An organelle that produces most of a cell’s ATP through aerobic cellular respiration.

Ribosome

A structure that uses mRNA instructions to join amino acids together and build proteins.

Rough endoplasmic reticulum

A membrane network covered with ribosomes that helps make, fold, and transport proteins, especially proteins intended for secretion or membranes.

Smooth endoplasmic reticulum

A membrane network without ribosomes that makes lipids, helps detoxify substances, and stores calcium ions in some cells.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids into vesicles for delivery. Aka the post office!!

Lysosome

An organelle containing digestive enzymes that break down cellular waste, worn-out organelles, and materials brought into the cell.

Peroxisome

An organelle that helps break down fatty acids and detoxify harmful substances. Its enzymes also break down hydrogen peroxide.

Cytoskeleton

A network of protein fibers that supports cell shape, organizes cell contents, and helps with movement and transport within the cell.

Microvilli

Small projections of the plasma membrane that increase surface area for absorption. They are common on cells lining the small intestine.

Diffusion

The net movement of particles from an area of higher concentration to an area of lower concentration. It does not require cellular energy.

Filtration

The movement of water and small dissolved substances across a membrane because of a pressure difference. An example occurs in the kidneys.

Solute pumping

A form of active transport in which membrane proteins use energy, typically ATP, to move solutes against their concentration gradient.

Endocytosis

The process of bringing material into a cell by surrounding it with the plasma membrane and forming a vesicle. It requires energy (active transport).

Exocytosis

The process of releasing material from a cell when a vesicle fuses with the plasma membrane. It requires energy (active transport).