LO2

Anion

negatively charged ions

What is pH? What does it mean for a solution to be acidic or basic?

pH is a measure of the relative amounts of H+ it contains. An acidic solution has a pH less than 7 due to increased levels of H+. A basic solution will have a pH over 7 due to decreased amounts of H+ and increased OH-.

Cation

positively charged ions

Ribosomes

synthesize proteins destined to be incorporated into the plasma membrane, exported from the cell, or housed within lysosomes. Free ribosomes synthesize proteins for use within the cell.

In your own words, explain the action of G-proteins (2nd-messenger processes).

1.A ligand binds to a receptor then activates that receptor and binds to the G-Protein 2. The G-protein is then activated and releases GDP and binds to GTP and then activates an effector protein. 3. The effector protein changes shape, and releases enzymes that then activate the second messenger and activate the other enzymes in the pathway.

What is a buffer? What are the major buffers in the blood?

A buffer is either a single type of molecule or two or more different types of molecules that helps prevent pH changes if either acid or base is added. A buffer acts to either accept H+ from added acid or to donate H+ to neutralize added base. Bicarbonate accepts H+ as acid is added to the blood and carbonic acid releases H+ as base is added.

What is the difference between a peptide and a protein?

A protein has more than 200 amino acids linked Peptide contains 3-20

What is adenosine triphosphate (ATP)? What is the physiological significance of ATP?

ATP is an important nucleotide composed of the nitrogenous base adenine, a ribose sugar, and three phosphate groups. ATP is the central molecule in the transfer of chemical energy within cells.

How are amino acids organized? What are the major categories of amino acids?

Amino acids are organized into groups based on the chemical characteristics of their R group. Each amino acid is categorized as nonpolar, polar, charged and those having special functions.

What are the major categories of protein function?

Catalysts, defense, transport, support, movement, regulation, storage.

Briefly describe the four properties of water that make it unique.

Cohesion: the attraction between water molecules Surface Tension: the inward pulling of cohesive forces at the surface of water. Adhesion: the attraction between water molecules and a substance other than water. High Specific Heat: most of the energy imparted into water during heating is first used to break hydrogen bonds. High Heat of Vaporization: because of the hydrogen bonds.

What are the structural and functional differences between DNA and RNA?

DNA has a phosphate group, deoxyribose sugar and a nitrogen base (adenine, thymine, cytosine and guanine). Has a double helix that is formed by hydrogen bonds between polynucleotides. DNA stores an organism's genetic material, replicates itself, provides code or template for the particular sequencing of amino acids that bond together and make a protein. RNA has a phosphate group, ribose sugar and bases (adenine, uracil, cytosine, guanine). Single stranded and moves out of nucleus to preform protein synthesis.

Define diffusion and concentration gradient. How are they related?

Diffusion: the new movement of a substance from where it is more concentrated to where it is less concentrated Concentration Gradient: the process of particles moving through a solution from an area of higher number of particles to an area of lower number of particles. The areas are typically separated by a membrane. Molecules diffuse from an area of high concentration to an area of low concentration; the molecules will diffuse down the concentration gradient.

What are the biological consequences of excess free hydrogen ions in the blood?

Excess free hydrogen ions in the blood will cause the blood pH to decrease and become more acidic.

During kidney dialysis, a person's blood is passed through a bath that contains several ions and molecules. The blood is separated from the dialysis fluid by a membrane that allows water, small ions, and small molecules to pass, but does not allow large proteins or blood cells to pass. What should the composition of dialysis fluid be for it to remove urea (a small molecule) without changing the blood volume (removing water from the blood)?

For the dialysis fluid to remove urea without removing water, it should not contain urea. Because urea is a small molecule, it will diffuse through the dialysis membrane from an area of high concentration (the blood) to an area of low concentration (the dialysis fluid). To prevent an associated osmotic water movement, the dialysis fluid should have an osmotic concentration similar to that of blood plasma, but with higher concentrations of solutes such as bicarbonate ions or glucose. As urea diffuses into the dialysis fluid, glucose and bicarbonate diffuse into the blood; as a result, the solute concentrations remain in balance and no osmotic water movement occurs.

What is the major difference between organic and inorganic compounds?

Inorganic compounds do not contain carbon and include water, salts and many acids and bases. Organic compounds contain carbon and include carbohydrates, fats, proteins, and nucleic acids.

Vesicular Transport

Involves a vesicle

Active Transport

Ion or small molecule moved against its concentration gradient

Describe how an ion is formed.

Ions are formed when atoms lose or gain electrons.

What is the major difference between meiosis and mitosis?

Mitosis occurs in somatic cells., produces 2 daughter cells, cells produced are identical to the parent cell. Meiosis occurs in sex cells, involves two cell divisions, leads to the production of germ cells that give rise to gametes. Cells produced are not identical to the parent cell.

Define molarity.

Molarity is the moles of solute per liter of solution.

What are the principle elements in the body? List the 4 major elements in order of their abundance.

Oxygen, Carbon, Hydrogen & Nitrogen

Describe the following terms: permeability, freely permeably, impermeable

Permeability: restricts movement, lets some stuff pass, while restricting others Freely permeably: lets anything pass Impermeable: nothing out

Explain the polarity of molecules.

Polarity of molecules is determined by the bonds that make up the molecule. Polar molecules contain more polar covalent bonds between the atoms. Nonpolar molecules contain primarily nonpolar covalent bonds.

What is resting membrane potential?

Resting membrane potential is the potential energy when a cell is at rest. Resting membrane potential varies by cell type, but typically ranges between -50mV and -100mV. Nerve cells have a resting membrane potential of - 70mV.

What types of molecules can diffuse through the plasma membrane?

Small and nonpolar molecules (respiratory gases O2, CO2). Small fatty acids, ethanol and urea.

Electrolytes

Substances that both dissolve and dissociate in water, such as salts, acids, and bases, can readily conduct an electric current.

What is the approximate osmolarity of the extracellular fluid? Of the intracellular fluid?

The approximate osmolarity of extracellular fluid is 300 mOsm. The approximate osmolarity of intracellular fluid would be the same at 300 mOsm.

What are the important factors that influence diffusion?

The concentration gradient between the inside and the outside of the cell. The chemical characteristics of the diffusing solute, the distribution of most molecules and ions associated with cells is not equal between the inside and the outside of a cell.

When a person receives intravenous fluids to help build up blood volume, why is it important for the fluid to be isotonic?

The fluid would need to be isotonic to prevent the cells from losing or gaining water. If the fluid were hypotonic, the fluid would cause the cells to swell and possibly rupture. If the fluid were hypertonic, it would cause the fluid to leave the cells, causing them to shrivel.

What determines a molecule's solubility or lack of solubility in water?

The polarity of the molecule. In order for a molecule to dissolve in water it must be electrically attracted to water molecules, meaning it must have a sufficient number of polar bonds or ionized groups. Polar molecules are soluble in water, nonpolar molecules are not.

What are the functions of the cell membrane?

The primary function of the cell membrane is to protect the cell. Selectively permeable boundary, regulates entry and exit of ions, nutrients and waste molecule. Electrochemical gradients, establishes and maintains. Communication, contains receptors that recognize and respond to molecular signals.

Why is the interior of a cell at a relatively steady resting potential of -70mV?

The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion. Since the concentrations of ions inside and outside of the cell are kept relatively consistent it makes sense that the resting potential of the interior of the cell would stay relatively steady. If it was at 0, you would be dead.

What role does the sodium-potassium exchange pump play in stabilizing the resting membrane potential?

The sodium-potassium pumps are significant in maintaining the gradients of both sodium and potassium following their diffusion. Each type of ion is pumped back up its concentration by the sodium potassium pumps. Sodium and potassium are moved in opposite directions; sodium pumped out of the cell, potassium transported in. The sodium potassium pumps maintain ion gradients.

Intravenous injection of KCl could be fatal. Why?

When the injection of KCl is given and stays outside the cell, causes the imbalance in resting membrane potential because number of potassium in the cell and outside is not balanced. There would be way too much potassium introduced at one time which means the levels of sodium and potassium would be extremely in balanced. The extracellular concentration of potassium would be so high it could become toxic and cause the heart to fibrillate causing death.

Lysosomes

breakdown molecules within vesicles that enter cell by endocytosis, remove damaged organelles and cellular components, and break down cellular components following cellular death.

Mitochondria

digest organic molecules (glucose) to produce ATP by aerobic cellular respiration.

Microvilli

increase the surface area of the plasma membrane for more efficient membrane transport

Hydrostatic Pressure

is the pressure exerted by a fluid on the inside wall of its container.

Osmotic Pressure

is the pressure exerted by the movement of water across a semipermeable membrane due to a difference in solution concentration.

Cilia

keep sensitive internal passage ways free of mucus or foreign particals

Simple Diffusion

molecules that are small and nonpolar move into or out of a cell down their concentration gradient.

Osmosis

movement of water across a semipermeable membrane

Endoplasmic Reticulum

responsible for the transportation of proteins and other carbohydrates and provide the increased surface area for cellular reactions

Facilitated Diffusion

small solutes are transported either into or out of the cell, down their concentration gradient, must be assisted by plasma membrane proteins.

Hypertonic

solution has a higher concentration of solutes and a lower concentration of water than the cytosol.

Hypotonic

solution has a lower concentration of solutes and a higher concentration of water than the cytosol.

Crenation

the process of the cell shrinking when the difference in concentration is large.

Hemolysis

the specific term for rupturing erythrocytes

Hydrophobic

water-fearing, molecules that do not dissolve in water

Hydrophilic

water-loving, molecules that favorably interact with water molecules