Human Biology & Molecules

• Atoms and molecules are nonliving materials from whihc all of nature is built
• Cells are organized into increasingly complex levels:
• -tissues
• -organs
• -organ systems
• -organisms
• Organisms, in turn, form:
• -populations
• -communities
• -ecosystmes
• -biosphere

• homo, same, and stasis, standing
• A physiological state in which the physical and chemical conditions of the internal environment are being maintained within tolerable ranges

dynamic balance

Ex: About 12 to 24 hours after the last meal, a person's blood sugar level normally varies from 60 to 90 milligrams per 100 millileters of blood, though it may rise to 130 mg/100 ml after meals high in carbohydrates. That the blood sugar level is maintained within a fairly narrow range despite uneven intake of sugar is due to the body's ability to carry out homeostasis.

• Taking in energy and materials
• Sensing and responding to changes in the environment
• Consisting of one or more cells
• Reproducing and growing

• Producers: plants, trap energy of the sun by photosynthesis
• Consumers: animals, feed on the stored energy in plants, using cellular respiration
• Decomposers: bacteria and fungi, break down the biological molecules of other organisms in order to recycle raw meterials

The sun

A related set of hypotheses that form a broad-ranging explanation of many phenomena.

Theories are accepted or rejected on the basis of tests and are subject to revision (as new evidence comes to light) - Universally accepted = law

• REaliability of Data:
• Sample size:large enough to represent the whole
• Trials:
• Hypotheses: Possible explanation of a natural event or observation, educated gueses using all known information
• Controls:allows a standard of comparison for the experimental group.
• Control groups: the standard to compare test group against.
• Independent variables:
• Dependent variables:
• Aspect of an object or event that may differ with time or between sujects

D. Bacteria

A eukaryotic cell is a cell that has a "true nucleus" and other membrane-bound organelles.

A single-celled organism that has not nucleus or any of the other membrane-bound organelles characteristic of eukaryotic cells

Example: Bacteria

No

Critical thinking is an objective evaluation of information - not opinions or hearsay

E. trans fats

are part of the atomic nucleus and have a positive charge. Their quanitity is called the atomic number (unique for each element)

Have a negative charge. Their quanitity is equal to that of the protons. They move around the nucleus

balance (=)

also part of the nucleus; they are neutral. Protons plus neutrons = atomic mass number

Varies

protons and electrons

The time it takes for half of a quantity of radioisotope to decay into a more stable isotope

Varying forms of atoms andare the basis for organization of materials and the flow energy in living things. how they interact & bind to molecules

A sugar or other molecule in which radioisotopes have been substitued for some atoms

Uses the radiation from isotopes to destroy or impair the activity of cells that do not work properly, such as cancer cells

Destroy cancer cells - iodine

• A union between the electron structures of atom (most stable when outer orbital is filled)
• In chemical reactions, an atom can share electrons, with another atom, accept extra electrons, or donate electrons
• Electrons are attracted to protons, but are repelled by other electrons
• Orbitals can be thought of as occupying shells around the nucleus, representing different energy levels

• Molecule: contain more than one atom of the same element; N₂
• Compounds: consist of two or more elemetns in strict proportions (can have more than 1 atom)
• Mixture: an intermingling of molecules in varyng proprtions

• Joins atoms that have opposite charges 1(+) 1(-)
• Gives atom to another one
• When an atom loses or gains one or more electrons, it becomes positively or negatively charged (an ion)
• Linked by mutual attraction of opposite charges, for example NaCl (sodium chloride)
• give away = more (+)
• take = more (-)

• The bond formed when atoms SHARE electrons.
• Strongest bond
• nonpolar - share electrons equally
• polar - share electrons unequally (slight difference in charge between the two atoms)

• Weak bond
• joins a hydrogen (H+) atom in one polar molecule with an electronegative atom in another polar molecule.
• Weak on (-)(+) end of molecules

• Water is polar molecule because of a slightly negative charge at the oxygen end and a slightly positive charge a the hydrogen end
• Water molecules can form hydrogen with each other
• tends to stabilize temperature because it has a high heat capacity (absorb considerable heat before its temperature changes)
• Keeps stability - evaporative and freezing processes
• Biological solvent -

• Polar
• water loving

Example: sugar, salt

• Nonpolar
• water dreading
• repelled by water

Example: oils

the ability to absorb considerable heat before its temperature changes

Water can absorb and hold heat and tend to stablize temperature because it has a high heat capacity

an electron

This happens when oxidatins in our cells realease highly unstable molecules called free radicals

Substance that can give up an electron to a free radical before the rouge does damage to DNA or some other vital cell component

Example: hormone melatonin

• Indicates the concentration of hydrogen ions
• the greater the H⁺ the lower the value on the pH scale (more acidic)
• the scale extends from 0 (acidic) to 7 (neautral) to 14 (basic)

If a molecule contains carbon and at least one atom of hydrogen it is considered organic

Proteins that speed up metabolic reactions

Give up hydrogen ions in a solution

Release ions that can combine to hydrogen

Example: Baking Soda

• Protect against shifts in pH
• Combine with, r release hydrogen to prevent drastic changes
• Bicarbonate is one of the body's major buffers

• atoms or groups of atoms covalently bonded to carbon backbone - convey distinct properties, such as solubility, to the complete molecule
• set group of atom when attached give it a property

• dehydration synthesis
• means to take out water
• two molecule fragments joined to form a new compound (H⁺ & OH^-)

• the reverse of condensation reaction
• one molecule is split by the addition of H⁺ and OH^- (from water) to yeild the individual components
• means to add water

a large molecule built of three to millions of subunits

• carbohydrates
• lipids
• proteins
• nucleic acids
• contain carbon
• living organisms mostly oxygen, hydrogen, and carbon

• Simple sugar or larger molecule composed of sugar units
• The most ABUNDANT biological molecules
• serve as energy sources - structural roles
• Monosaccharides (simple sugar)
• Oligosacharides (short-chain carbohydrates)
• Polysaccharides (complex carbohydrates)

• Glucose - energy source
• Sucrose ( a disaccharide) - Most common form of sugar; the form transported through plants
• Starch, glycogen - Energy source
• Cellulose - structural roles

• compsed mostly of nonpolar hydrocarbon and are hydrophobic
• do not dissolve in water but do dissolve in nonpolar substances, cuch as alcohols and other lipids
• Glycerides - glycerol backbone with one, two, or three fatty acid tails (e.g. tryglycerides)
• Phospholipids - Glycerol backbone, phosphate group, another polar group, and often two fatty acids
• Waxes - alcohol with long-chain fatty acid tails
• Sterols - four carbon rings; the number, position, and type of functional groups differ among sterols

• Fats (butter) & Oil (corn oil) - energy source
• Lecithin - key componenet of cell membranes
• Waxes in cutin - conservation of water in plants
• Cholesterol - component of animal cell membranes; precursor of many steroids and vitamin D

• Most diverse of the large biological molecules
• function as enzymes in cell movements; as storage and transport agents, as hormones, as antidisease agents, and as structural material througout the body
• One or more polypeptide chains, each with as many as several thousand covalently linked amino acids
• Mostly fibrous proteins - long strands or sheets of polypeptide chains; often strong water insoluble
• Mostly globular proteins - one or more polypeptide chains folded int oglobular shapes; many roles in cell activities

• Keratine - structural component of hair, nails
• Collagen - structural component of bone
• Mysoin, actin - Functional components of muscles
• Enzymes - Great increase in rates of reactions
• Hemoglobin - Oxygen transport
• Insulin - Conrol of glucose metabolism
• Antibodies - Immune defense

• Primary Structure - defined as the chain (polypeptide) of amino acids; determines the shape and function of proteins by positiong different amino acids so that hydrogen bonds can form between them and by putting R groups in positions that force them to interact
• Secondary structure - helical coil or sheetilke arrayresult from hydrogen bonding of side groups on the amino acid chains (coil = alpha helix or fold - beta pleated)
• Tertiary structure - caused by interactions among R groups, resulting in complex three dimensional shape (R groups interact with each other)
• Quaternary structure - two complete different chains work together to form globular or fibrous proteins (to do a job)

• Gycoproteins - sugar attached; lipoproteins have lipids
• Cetain proteins combine with triglycerides, cholesterol, and phospholipids to form lipoproteins for transport in the body
• Form when oligosaccharides are added to proteins
• funcion in cells recongizing each other
• Denaturation is when a prtein's shape is disrupted through high temperatures or chemicals (often irreversible; like a scrambled egg or hair perm)

• Nucleotides are energy carriers, have five-carbon sugar (ribose or deoxyribose), nitrogen-containing base, and a phosphate group
• ATP molecules - transfer energy
• coenzymes - accpet and transer hydrogen atoms and electrons during cellular reactions
• Nucleic acids include:
• DNA - double-stranded; genetic messages are encoded in its base sequences
• RNA - single stranded; it functions in the assembly of proteins