Anatomy and Physiology Body Organization and Cellular Biology

Vocabulary flashcards covering levels of body organization, cellular structures, organelles, homeostasis, chemical bonds, biomolecules, gene expression, cell cycle, and membrane transport.

Chemical level

Simplest level of body organization; consists of atoms and molecules (water, proteins, DNA) that create the structures driving all bodily functions.

Cellular level

Level where molecules combine to form cells, the basic structural and functional units of life, containing organelles and specializing into specific types (muscles, nerves, blood cells).

Tissue level

Level consisting of groups of similar cells working together, including muscle, epithelial, nervous, and connective tissue.

Organ level

Level consisting of structures composed of 2 or more tissue types that work together to perform specific functions (examples include stomach, brain and heart).

Organ system level

Level consisting of groups of organs working together for a common purpose, while different organ systems also cooperate to maintain life (e.g., digestive, circulatory, and nervous systems).

Organism level

The levels of body organization are a nested system; atoms build molecules, molecules build cells, and so on.

Plasma (cell) membrane

Surrounds cell, defines boundaries, and is made of proteins and lipids; composition and function can vary from one region of the cell to another.

Extracellular fluid (ECF)

Fluid outside of cell.

Intracellular face

The side of the membrane that faces the cytoplasm.

Extracellular face

The side of the membrane facing outwards.

Cytosol

Clear fluid (intracellular fluid, ICF) in which the cytoskeleton, organelles, and inclusions are embedded.

Cytoplasm

Contents of a cell/fluid between its plasma membrane and its nuclear envelope, consisting of cytosol, organelles, inclusions, and the cytoskeleton.

Ribosomes

Small granules of protein and RNA that serve as the site of protein synthesis; found in nucleoli, in cytosol, and on outer surfaces of rough ER and nuclear envelope.

Rough endoplasmic reticulum

Composed of parallel, flattened sacs covered with ribosomes; continuous with outer membrane of nuclear envelope; produces phospholipids and proteins of the plasma membrane, and synthesizes proteins that are packaged in other organelles or secreted from cell.

Smooth endoplasmic reticulum

Lacks ribosomes, with cisternae more tubular and branching; synthesizes steroids and other lipids, detoxifies alcohol and other drugs, and manufactures all membranes of the cell.

Centriole

Helps with cell division and gives attachment to spindles, which help to move apart the sister chromatids.

Homeostasis

The tendency of a living body to maintain relatively stable internal conditions in spite of greater changes in its external environment.

Dynamic equilibrium

The internal state of the body in which there is a certain set point or average value for a given variable, around which conditions fluctuate slightly.

Covalent bond

Formed by mutual sharing of electrons, shown by a solid line (ex: H-H) where 1 line means 1 electron shared; covalent bonds do not dissociate in solution.

Ionic bond

A chemical bond involving the attraction of a cation.

Hydrogen bond

A weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen/nitrogen atom in another.

Electrolytes

Substances that ionize in water and form solutions capable of conducting electricity.

Isotopes

Atoms of same elements with different numbers of neutrons; have different atomic masses, but are electrically (chemically) identical.

Isomer

Molecules with identical molecular formula but different arrangements of their atoms.

Anions

Ion with more electrons than protons and consequently a net negative charge.

Cations

Ion with more protons than electrons and consequently a net positive charge.

Valence electrons

Electrons in the outermost shell that determine chemical bonding properties of an atom and how atoms react.

Mitochondria

Powerhouse of the cell, generate most ATP.

Polysaccharides

A polymer of simple sugars, for example: glycogen, starch and cellulose.

Starch

Corresponding energy storage polysaccharide of plants.

Glycogen

An energy-storage polysaccharide made by cells of the liver, muscles, brain, uterus, and vagina.

Cellulose

Structural polysaccharide that gives strength to the cell wall of plants.

Codon

3 base sequence in mRNA; 64 possible codons available to represent the 20 amino acids (61 code for amino acids; 3 are stop codons).

Stop codons

UAG, UGA, and UAA: signal "end of message," like a period at the end of a sentence.

Start codon

AUG codes for methionine, and begins the amino acid sequence of the protein.

Transcription

DNA codes for mRNA, occurring within the nucleus; the process of copying genetic instructions from DNA to mRNA.

Translation

mRNA codes for protein, usually occurring within cytoplasm; process that converts in the language of nucleotides into the language of amino acids.

Lipids

Hydrophobic organic compound composed mainly of carbon and a high ratio of hydrogen to oxygen; includes fatty acids, fats, phospholipids, steroids, and prostaglandins.

Gene

An information-containing segment of DNA that codes for the production of a molecule of RNA that plays a role in synthesizing one or more proteins.

G1 phase

First gap phase: growth and normal metabolic roles, interval between cell birth and DNA replication, cell carries out normal tasks and accumulates materials for next phase.

S phase

Synthesis phase: DNA replication, cell replicates all nuclear DNA and duplicates centrioles.

G2 phase

Second gap phase: growth and preparation for mitosis, interval between DNA replication and cell division, cell repairs DNA replication errors, grows and synthesizes enzymes that control cell division.

G0 phase

Describes cells that have left the cycle and cease dividing for a long time (or permanently).

Interphase

G1, S, and G2 are all in interphase; interphase is the gap between one cell division and the next.

Mitosis

The 5 stage process (prophase, prometaphase, metaphase, anaphase, and telophase) by which somatic cells divide into two identical daughter cells following DNA duplication.

Osmosis

The movement of water across a cell membrane towards highest solute concentration (or diffusion of water through a differentially permeable membrane).

Hypotonic solution

Has fewer non-permeable solutes outside the cell than inside the cell, resulting in water flowing into the cell; if too much water flows in, it can swell and possibly burst.

Isotonic solution

Has the same number of non-permeable solutes outside and inside the cell, resulting in no net water movement and balanced water intake and output.

Simple diffusion

The diffusion of solutes through a differentially permeable membrane; movement of particles from area of high concentration to area of low concentration, stopping when movement is equal.

Facilitated diffusion

Large molecules are unable to cross the membrane, therefore using protein carrier molecules in plasma membrane to move across the membrane without ATP.

Abdominal regions

Nine regions of the human torso demarcated by grid lines, including the hypochondriac, lumbar, iliac, epigastric, umbilical, and hypogastric regions.

Osmosis solution types

Behavior and shape changes of cells placed in hypotonic, isotonic, and hypertonic solutions based on relative solute concentrations.