A&P Exam 1

Protons

positively-charged subatomic particles in the atomic nucleus

Atomic number

The number of protons in the atomic nucleus

Electrons

negatively charged subatomic particles in orbitals

What is the relationship between protons and electrons in an atom?

In a neutral atom, the number of protons equals the number of electrons, balancing the overall charge.

Inert elements

atoms with their valence shells complete and are therefore chemically unreactive

Chemically reactive elements

atoms in the elements have incomplete valence shells and are therefore unstable

How do chemically reactive atoms achieve stability?

By forming chemical bonds with other atoms using their valence electrons

Ionic bonds

Complete transfer of electron from one atom to the other resulting in charged particles called ions

Cation

Positively charged ion

Anion

Negatively charged ion

Covalent bonds

Electrons shared between atoms to attain stability

Nonpolar covalent bonds

Electrons are shared equally between the atoms involved

Polar covalent bond

Unequal sharing of electrons

Hydrogen bonds

a weaker bond that forms between hydrogen atoms (electropositive) and electronegative ions; hydrogen bonds form between atoms already involved in Polar Covalent Bond

Inorganic compounds

Do not contain carbon chains (Ex: water, acids, bases, salts)

Organic compounds

Contain carbons that are covalently-bonded (Ex: carbohydrates, lipids, proteins, nucleic acids)

What are the characterstics of water?

1. The most abundant compound in the body; 70% of volume of cells

2. Known as the universal solvent

3. High heat capacity; absorbs body heat

4. High heat of vaporization; cools the body

5. Cushions around body organs

Acids

Substances that release hydrogen ions; known as proton donors

Bases

Substances that accept hydrogen ions; known as proton acceptors

Relationship between hydrogen ion concentration and pH

Hydrogen ion concentration is inversely proportional to the pH

Three types of carbohydrates

Monosaccharides, disaccharides, and polysaccharides

Monosaccharides

General formula is (CH2))n; sweet and soluble in water (Ex: hexose, pentose)

Disaccharides

Composed of 2 hexose sugars; sweet and soluble in water

Polysaccharides

composed of long chains of glucose; storage form of glucose; known as starch in plant cells and as glycogen in animal cells; not sweet, insoluble in water

Lipids

Hydrophobic substances insoluble in water

Neutral fats

Most abundant form of fat

Unsaturated fats

type of neutral fat where at least one double covalent bond is in the carbon chain; liquid at room temperature; plant sources — olive oil

Saturated fats

type of neutral fat where single covalent bonds exist between all carbons in the chain; solid at room temperature; animal sources — butter

Low Density Lipoprotein (LDL)

Bad Cholesterol

High Density Lipoproteins (HDL)

Good cholesterol

Lipoproteins

Each contain different amounts of lipids and proteins; the more protein, the higher the density, the more lipids, the lower the density

Atherosclerotic plague

Can clog up arteries and cause atherosclerosis which can lead to myocardial infarction (heart attack) or ischemic stroke (brain attack)

Coronary Heart Disease (CHD)

#1 killer in both me and women, occurs if plaque builds up in the coronary arteries which supply oxygen-rich blood to the myocardium in the heart wall

Amino Acids

Building blocks of proteins; each has an amino terminal as a abse and carboxyl terminal as an acid

Essential amino acids

Must be ingested in the diet

Non-essential amino acids

Can be synthesized by the body via transamination reaction

Structural levels of proteins

Primary, secondary, tertiary, and quaternary

Primary structure

linear polypeptide chain indicating type and position of amino acids

Secondary structure

alpha helix coiled polypeptide chain held together by hydrogen bonds; beta pleated sheet linked side by side by hydrogen bonds

Tertiary structure

secondary structure fold upon themselves to give compact, globular molecule

Quaternary structure

2 or more polypeptide chains held together by disulfide bonds

Fibrous Proteins

Extended/strand like; insoluble in water; provides mechanical support and tensile strength

Globular proteins

Compact/ball-like; soluble in water and sensitive to pH and temperature; chemically active and known as functional proteins

Principle of complementarity of structure and function

The biochemical reactions occurring in a cell are dictated by the subcellular structures present in the cell

Plasma membrane

defines the boundary of a cell; composed of 2 rows of phospholipids with the polar hydrophilic heads interacting with extracellular fluid and the intracellular fluid with the nonpolar hydrophobic tails tucked inside

Cytoplasm

the inferior of the cell between the plasma membrane and the nucleus; contains the cytoplasmic organelles

Nucleus

contains the genes which control activities of the cell

Fluid mosaic model

Moves constantly due to the plasma membrane in flux forming a mosaic

Integral proteins

span the plasma membrane exposed on one surface or both surfaces of the plasma membrane

Transmembrane proteins

exposed on both surfaces of the plasma membrane

Peripheral proteins

attached to integral proteins or the phospholipid heads on the extracellular face of the plasma membrane

Functions of membrane proteins

1. Intracellular joining to form junctions between adjacent cells

2. As carrier or transport proteins

3. As signal molecules for cell to cell recognition

4. As receptors for chemical mediators such as hormones

5. As membrane protein may act as membrane bound enzymes

Types of membrane junctions

Tight junctions, desmosomes, gap junctions

Tight junctions

fusion of integral proteins in plasma membrane of adjacent cells that prevent the transfer of substances directly between adjacent cells

Desmosome

linker proteins extending from plaques on the cytoplasmic surface of the plasma membrane of adjacent cells interdigitate to hold the cells together and prevent their separation

Gap Junction

formed by hollow cylinder called connexon; it allows for the rapid transfer of ions between cells

Membrane transport

the plasma membrane is a selective barrier 2 main types of membrane transport, passive and active transport

Passive membrane processes

substances cross the plasma membrane without any energy input; 2 types diffusion and filtration

Diffusion

movement of substances from area of higher concentration to area of loweer concentration/down a concentration gradient; 3 subtypes simple diffusion, facilitated diffusion, osmosis

Filtration

movement of solution from area of higher pressure to area of lower pressure; down a pressure gradient

Active membrane processes

the cell provides energy required to move substances across the plasma membrane

Active membrane transport

movements of solute from area of lower concentration to area of higher concentration against a concentration gradient hence, active transport is also known as “solute pumping”

Simple diffusion

nonpolar/hydrophobic/lipid-soluble substances diffuse through the plasma membrane Ex: oxygen, carbon dioxide

Facilitated diffusion

transport of large/polar substances mediated by carrier proteins embedded in the plasma membrane; exhibits saturation and specificity

Osmosis

movement of water from area of lower solute concentration to area of higher solute concentration through semi-permeable membrane

Tonicity

movement of water in and out of cells can change the shape or tone of cells

Isotonic solution

concentration of solution inside and outside of the cells is the same; the same amount of water moves in/out of the cells and thus, the shape of cells remain unchanged

Hypotonic solution

cells are placed in a solution with a lower concentration than solution inside cells; water moves via osmosis into the cells and the cells swell and eventually lyse

Hypertonic solution

cells placed in solution with a higher concentration than solution inside cells; water moves via osmosis from the cells and shrink

Filtration

movement of solution from area of higher pressure to area of lower pressure; down a pressure gradient

Active processes

energy (ATP) is required for the movement of substances across the plasma membrane

Active transport

movement of solute from area of lower solute concentration to area of higher solute concentration (against the concentration gradient); mediated by carrier proteins; exhibits saturation and specificity

Vesicular transport

active process where substances are moved in bulk by enclosing them in vesicles, energy (ATP) is required to move the vesicles

Exocytosis

movement of substances enclosed in vesicles from the interior of cells to the exterior

Endocytosis

movement of substances enclosed in vesicles from the exterior of cells to the interior

Phagocytosis

movement of solid particles from the exterior into the cell; solid particles are enclosed in vesicles called phagosomes; lysosomes fuse with them to digest the phagosomes

Pinocytosis

movement of solution into cells by enclosing the solution in vesicles called pinocytic vesicles

Receptor-mediated endocytosis

substances bind to specific receptors on the surface of the cell and taken into the cell; exhibits saturation and specificity