1. Directional terms, Homeostasis and Body Chemistry Flashcards
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define ion
an electrically charged atom (gained or lost an electron)-
electrolytes are substances that dissociate into ions, in aquous solution (water pulls apart the ionic bond)
define pH
measures the amount of H+ in a solution
low pH (\<7) = acidic (lots of H+) high pH (\<7) = basic (lots of OH)
Describe the structure of an atom
Atom contains 3 types of subatomic particles- protons, electrons and neutrons.
Protons and Neutrons reside within the nucleus of the atom, and make up the mass of the atom (electron mass is negligible).
Electrons orbit around the nucleus in energy shells.
Protons have a positive charge, neutrons have no charge. Electrons have a negative charge
Each energy shell has a specific # of electrons that can orbit. The outer shell is called the valence shell, which determines the chemical properties of the atom.
Element’s weight is based on Protons + Neutrons (note electrons have no weight)
Electron’s atomic number is # of Protons (which is therefore same # of Electrons, for neutral atom)
Sometimes an atom with same number of proton (i.e. same element) can have different number of neutrons, forming isotope
explain the importance of buffers in the regulation of pH
body has different fluids that have very specific pH levels, to support function (e.g. acidic gastric juice helps break down food and kill microbes in stomach)
body is very sensitive to pH levels- important it sits within narrow limits
body naturally produces acids / base through normal metabolic processes, that disrupt the pH levels of different fluids
buffers are used to couteract increase of acid / base, through binding to H+. this process is reversible, so buffer can continually respond to changes in acidity / base through releasing/ accepting H+
this maintains pH levels within normal limits
Buffers can only work if there is a viable way to excrete the excess acid/base - so buffer + excretory system must work together
- Lungs- too much C02 increases the acidity of the body, so lungs support pH homeostasis by increasing / decreasing amount of CO2 released, as pH levels change. (when pH drops (too much H+) the lungs increase rate of respiration
- kidneys - can adjust how much H+ / OH- is reabsorbed / released
Blood pH is between 7.35-7.45.
- acidosis- when blood pH is <7.35. More common as body tends to be more acidic. occurs when body has respiratory issues (Cannot release CO2 which accumulates, thus increasing H+) / renal issues affecting excretion of H+
- alkalosis - when blood pH is >7.45. When body has released a lot of acid - e.g. excess vomiting / diaorrhea.
Discuss matter- how does it bond, what can it form
types of bonds
- ionic bonds- atoms give / take electrons to become ions (cations (give up e) / anions (take e))
-
covalent bonds- atoms share electrons
- non-polar- electrons shared equally
- polar- electrons shared unequally
Types of molecules formed
- elemental molecules +2 same atoms)
- compounds with +2 different atoms
Define the term internal environment
- water based medium in which body cells exist.
includes fluid within Cells (intracellular) surrounded by intercellular fluid, from which they absorb oxygen / nutrients and release waste- these are then absorbed / excreted into blood
Intracellular- ~70%
Intercellular - 30% (23% Interstitual, 7% plasma/other fluid)
define homeostasis
body’s ability to keep internal environment within relatively constant state, regardless of changes in the external environment. includes homeostasis of temperature, blood pressure, pH, glucose levels
Describe carbohydrates
organic molecules- CHO- carbon, oxygen, Hydrogen (1:1:2)
dissolve in water
three types
- Monosaccharides (E.g. glucose / fructose)
- Disaccharides
- Polysaccharides
- starch (plant storage)
- cellulose (used for cell walls)
- glycogen (animal storage)
- preferred source of energy for body
Describe lipids
diverse- all hydrophobic.
CHO (less O than Carbohydrates) + some have nitrogen / phosphorus
4 types
- triglyceride- fats and oils - Glycerol + 3 Fatty acids
- Phospholipid - 2 fatty acids + phosphate (hydrophilic)
- steroids (form cholesterol, bile salts, vit d synthesis, hormones)
- eicosanoids e.g. prostaglandins
Describe proteins
basic structural unit of tissues and hormones / enzymes
made up of enzymes
CHO and Nitrogen; plus nitrogen ‘R’ group which gives AA it’s unique property
20 used in principal building blocks of protein
can only be sourced externally, thus body needs to consume wide range of AA
Peptides - <10
polypeptides - 10>x<50
proteins- >50 AA’s joined together by peptide bonds
Describe Nucleic acids
Largest molecules- made up of nucleotide units (Sugar, nitrogen base, phosphate)
2 TYPES
- DNA- carry all genetic info to inform protein synthesis / when it will occur. Replicates itself before cell division
- 2 chains of Nucleotides, Bases are A,T,C,G
- RNA - involved in protein synthesis under direction of DNA
- 1 chain of nucleotides, bases are A,U,C,G
describe Adenosine Triphosphate (ATP)
organic compound
ATP stores energy in it’s bonds, which can fuel cell function
Carbs, lipids and proteins can undergo catabolic reactions to synthesize ATP
Describe chemical nature of enzymes
proteins. Biological catalysts (speed up reaction, but they themselves are not changed)
very selective and only catalyse one specific reaction
define diffusion
passive movement of molecules from H to L concentration- mainly in gas / liquid / solution
results in equal concentration on both sides of membrane
hydrophobic tails of cell membrane prevent free movement, but diffusion occurs when
- substance is lipid soluble
- small enough to pass through membrane channel
- assisted by carrier protein in the membrane
define osmosis
diffusion of water across semi permeable membrane, whereby particles can’t permeate. so you may be left with unequal water amount on each side of membrane.
osmosis causes blood cells to swell, when you drink lots of water so cells / interstitual fluid are isotonic
Compare and contrast active, passive and bulk transport of substances
Passive-
- substances can cross SP membrane without need of cellular energy
- substances move down concentration gradient from H- L
- hydrophobic (lipid soluble) substances cross alone
- hydrophilic substances (sodium, K, Ca) use water filled channels
- when subtances are too large / hydrophilic to cross, they can be aided by protein carriers that are substrate specific
Active
-substances cross SP membrane with support of cellular energy which powers protein ‘pump’ to move substances against conc. graident
Bulk transport
-transport of large particles in / out of cell (endocytosis / exocytosis) via vacuoles. can be phagocytic or pinocytic (droplets of liquid).
Superior
towards the head
inferior
towards the feet
anterior
front / towards the front
posterior
(dorsal)
behind
proximal
closer to the attachment of limb at the trunk
distal
further away on limb attached to trunk
lateral
away from midline
medial
closer to the midline
superficial
closer to the surface of the body (skin)
deep
further from the outside / surface of the body
define mixtues and three types
substances composed of 2+ intermixed components
3 types
-
Solutions- solute particles very tiny, and don’t settle out / scatter light. components fully intermixed to create homogenous composition. can be (can be solid, liquid, gas)
- solvent (substance that is in greatest amount)
- solute (substance present in smaller amount)
-
Colloids- solute particles larger than in a solution, and form different compositions throughout the mixture (heterogenous)
- can change from liquid to gel (e.g. gelatin)
- Suspensions- solute particles are large and settle out- heterogenous mixture where large solutes are suspended in solvent, and can easily settle out and separate from solvent (.e.g blood)
what is a chemical reaction
when chemical bonds are formed (anabolic reaction) or broken (catabolic reaction)
they result in absorption or release of energy
Rate of chem reaction dependent upon - temperature, concentration of particles, particle size (smaller are faster), presence of catalysts e.g. enzymes)
what is difference between organic and inorganic compounds
organic - contain carbon
body needs both
Describe water
inorganic compound
most abundant inorgantic compound in the body
unique characteristics - high heat capacity / high heat of vapourisation
polar solvent - enables even distribution of broken ionic compounds
cushioning- resilient cushion around certain body parts
reactivity- water molecules can be added / removed during chemical reactions
define salts
ionic compounds that contain cations other than H+ and anions other than OH-
Ions act as electrolytes- can conduct electric currents in solvent
salts dissociate when dissolved in water
define acids
compounds that contain Hydrogen, and release H+ Ions when dissolved in water
define base
compounds that contain hydroxide that take up H+ ions
define facilitated diffusion
diffusion with the aid of a channel or carrier protein
- channel protein - allow small substances like ions / water through the plasma membrane
- carrier protein- creates envelope for larger substances (glucose) that reshapes to deposit substance on other side of the membrane
filtration
passive movement of water / solutes through cell membrane, due to differences in pressure (from high to low pressure)
occurs in
-capillaries (water and solutes are forced out of the capillaries into the extracellular fluid surrounding tissues)
kidneys- blood is filtered in the kidneys during urine formation
Solute (protein) pumps
Active transport- use ATP to move substances across membrane, against their concentration gradient
2 types
- primary active transport- use ATP to change protein shape, allowing it to ‘pump’ solute across membrane
- secondary active transport- energy used in primary active transport is ‘stored’ and used to help other substances cross the membrane
