Chemical and Cellular Levels of Organization

Comprehensive practice flashcards covering the chemical and cellular levels of organization, including DNA replication, mitosis, and cancer biology, based on the CH 2 and CH 3 lecture transcripts.

Atoms

The smallest stable units of matter.

Molecules

Formed when atoms combine; their unique 3D shape and atomic components determine their function.

Cells

The smallest living units in the body.

Tissue level

A group of cells working together to perform one or more specific functions.

Organ level

Made of two or more tissues working together to perform specific functions.

Organ system level

A group of organs interacting to perform a specific function.

Element

A pure substance composed of atoms of only one kind that cannot be changed or broken down into simpler substances.

Isotopes

Atoms of the same element whose nuclei contain different numbers of neutrons; they are designated by their mass number.

Radioisotopes

Radioactive isotopes that spontaneously break down and give off measurable amounts of radiation.

Ionic bonds

Chemical bonds created by the attraction between anions ($-$) and cations ($+$).

Covalent bonds

Chemical bonds created by the sharing of electrons between atoms instead of gaining or losing them.

Hydrogen bonds

The attraction between a slight positive charge on a hydrogen atom and a slight negative charge on an oxygen, nitrogen, or fluorine atom.

Decomposition reaction

A reaction that breaks a molecule into smaller fragments ($AB \rightarrow A + B$).

Catabolism

Decomposition reactions of complex molecules within the body's cells and tissues that release energy for growth, movement, and reproduction.

Synthesis reaction

A reaction that assembles smaller molecules into larger molecules ($A + B \rightarrow AB$) by forming new chemical bonds.

Anabolism

The synthesis of new molecules within the body's cells and tissues, often considered an "uphill" process requiring energy.

Exchange reaction

A reaction where parts of reacting molecules are shuffled to produce new products ($AB + CD \rightarrow AD + CB$).

Activation energy

The amount of energy required for a biochemical reaction to take place.

Enzymes

Proteins that act as catalysts to speed up complex synthesis and decomposition reactions by lowering activation energy requirements.

High heat capacity

A property of water where an unusually large amount of heat energy is required to change the temperature of $1\text{\thinspace g}$ of water by $1^\text{\thinspace C}$, helping to stabilize body temperature.

Acidosis

A condition characterized by low blood pH; a pH below $7$ can produce a coma.

Alkalosis

Abnormally high blood pH ($>7.8$) that causes uncontrollable and sustained skeletal muscle contractions.

Monosaccharides

Simple sugars containing $3$ to $7$ carbons, such as glucose.

Polysaccharides

Complex carbohydrates such as cellulose (in plant cell walls) and glycogen (storage form of energy in muscle cells).

Triglycerides

Lipids composed of three fatty acids attached to a glycerol molecule, used for energy source, insulation, and protection.

Cholesterol

A common steroid that helps maintain fluidity of membranes and is used for hormone production.

Phospholipids

Structural lipids with hydrophobic tails and hydrophilic heads that help form and maintain cell membranes.

Peptide bonds

The bonds that join the $20$ different amino acids to form proteins.

DNA (Deoxyribonucleic acid)

A large organic molecule that contains genetic instructions for making proteins and determines physical characteristics.

ATP (Adenosine triphosphate)

A high-energy compound used for the storage and transfer of energy to power the cell ($ATP \rightarrow ADP + \text{energy}$).

Mitochondria

Organelles with double membranes and inner folds called cristae that produce 95\text{\thinspace %} of the ATP required by the cell.

Rough Endoplasmic Reticulum

A network of membranous channels with ribosomes that modifies and packages newly synthesized proteins.

Smooth Endoplasmic Reticulum

A network of membranous channels without ribosomes that synthesizes lipids and carbohydrates.

Lysosomes

Vesicles containing digestive enzymes for the intracellular removal of damaged organelles or pathogens.

Microvilli

Extensions of the plasma membrane containing microfilaments that increase surface area for absorption.

Somatic cells

Any cell type that does not produce sex cells (sperm and egg).

Mitosis

Cell division in which DNA is split equally into two daughter cells.

Interphase

The period of the cell cycle where DNA is copied and the cell prepared for division; consists of G1, S, and G2 phases.

Helicase

The enzyme that splits the double-stranded DNA molecule in half in the middle of the helix during replication.

DNA polymerase

The enzyme that adds new nucleotides to each side of the original parent DNA molecule during replication.

Prophase

The first stage of mitosis where chromatin condenses into visible chromosomes and spindle fibers extend between centriole pairs.

Metaphase

The stage of mitosis where chromatids move to a narrow central zone called the metaphase plate.

Anaphase

The stage of mitosis where the centromere of each chromatid pair splits and the two daughter chromosomes are pulled toward opposite ends of the cell.

Telophase

The final stage of mitosis where nuclear membranes re-form, nuclei enlarge, and chromosomes uncoil.

Cytokinesis

The division of the cytoplasm into two daughter cells, usually beginning with the formation of a cleavage furrow.

Metastasis

The process where malignant tumor cells break away and start new cancers at distant locations.

Telomeres

Segments at both ends of a chromosome with the repetitive sequence $TTAGGG$ that regulate how many divisions a cell can undergo.

Telomerase

An enzyme possessed by cancer cells that extends telomere lengths after each cell division, prolonging their life.

Transcription

The process in which the DNA/gene inside the nucleus is copied into a molecule called messenger RNA (mRNA).

Translation

The process where mRNA is threaded through ribosomes and tRNA carries amino acids to build a protein based on codons.

Facilitated diffusion

A process where nutrient molecules move down a concentration gradient using a carrier protein without using ATP.

Active transport

A transport process that requires energy from ATP to move molecules against a concentration gradient via carrier proteins.

Osmosis

The movement of water across a membrane toward a solution with a higher concentration of solutes.

Hemolysis

The bursting or rupturing of a cell, such as a red blood cell, when water flows into it in a hypotonic solution.

Crenation

The shriveling of a red blood cell when it loses water in a hypertonic solution.