Organisation of the human body Flashcards
Elements in the human body
Hydrogen - H - 1 - 9.5%
Carbon - C - 6 - 18.5%
Nitrogen - N - 7 - 3.3%
Oxygen - O - 8 - 65%
Fluorine - F - 9 - Trace
Sodium - Na - 11 - 0.2%
Magnesium - Mg - 12 - 0.1%
Phosphorous - P - 15 - 1%
Sulfur - S - 16 - 0.3%
Chlorine - Cl - 17 - 0.2%
Potassium - K - 19 - 0.4%
Calcium - Ca - 20 - 1.5%
Manganese - Mn - 25
Iron - Fe - 26
Cobalt - Co - 27
Copper - Cu - 29
Zinc - Zn - 30
Iodine - I - 53
Atomic number
The number of protons in the nucleus of the atom. It is also the number of electrons that orbit the nucleus.
Hierarchy within the body
Organ systems
Organs
Types of tissue
Cells
Organelles
Macro molecules
Molecules
Elements
Atoms
Metabolism
Biochemical reactions that occur within the body, divided into two phases: catabolism and anabolism.
Catabolism: chemical reactions that break down complex substances into simpler substances.
Anabolism: chemical reactions that build up simple substances into complex substances.
Cell respiration
The process of cells converting fuel into energy and nutrients.
Differentiation
The process by which an unspecialized cell becomes specialized.
Excretion
Removal of the waste byproducts of metabolic reactions.
Element
Only made up of one type of atom.
Atom
Smallest part of an element that has the characteristics of the element.
Consists of protons (+) found in the nucleus
neutrons (no charge or neutral) also found in nucleus
electrons (-) found in electron shell orbiting the nucleus
Bonding
Elements rarely exist alone in nature, and they combine to form compounds or molecules.
The type of bond depends on if the electrons in the outer shell are lost, gained or shared to meet the octet rule.
Octet rule
Atoms ideally want 8 electrons in the outer shell to be stable.
Chemical bonds
Force that holds positive and negatively charged atoms together in a compound or molecule. The four main types are Ionic, Covalent, Hydrogen and metallic
Ionic bonds
Loss of one or more electrons by one atom then gained by another.
Example: Sodium (Na) has one electron in outer shell and loses it to become stable. Now having one more proton makes it positively charged, called an ion. Chloride (Cl) has seven electrons in outer most shell, and tends to gain an electron to become stable. This makes it a negative charge of 1 ion. Both ions are now attracted to each other, and create sodium chloride (salt).
Ions
When an atom loses or gains an electron to become stable, is no longer neutral.
Cation is more protons than electrons, positively charged.
Vice versa is an Anion.
Covalent bonds
When non-metal atoms share electrons.
Example: Oxygen (O) has six electrons in outer shell and needs two more to become stable. Achieves this by sharing two atoms with another oxygen atom, creating Oxygen gas (O2).
Carbon makes up approximately 20% of body weight and always forms covalent bonds. Has four electrons to share with other atoms. Methane gas is formed when four carbon electrons are shared with four atoms of hydrogen.
Disulfide bonds
Covalent bonds formed between two atoms of sulphur, important for maintaing the shape of a protein. Insulin needs a specific shape to function and regulate blood glucose levels.
Hydrogen bonds
Do not share electrons but result from a property of hydrogen atoms. When a hydrogen atom shares its electron with another in a covalent bond, the protons get a slight positive charge. May gain slight attraction to another atom with slight negative charge like oxygen or nitrogen.
Hydrogen bonds are weak. Important for maintaining shape, such as for molecules like DNA where shape is integral for function.
Water (H2O) holds shape due to hydrogen bond. Important for ensuring blood flows in a continuous steam in vessels.
Matter
Most basic organisation is a chemical level. Matter exists in three states: solids, liquids, and gases.
Changes in state occur when matter transforms from one state to another. Solid to liquid (melting), liquid to gas (vaporisation/evaporation/boiling) energy is absorbed in the form of heat, gas to liquid (condensation), liquid to solid (freezing) energy is released as heat.
Solids
Atoms arranged in fixed positions with definite shape and volume.
Least amount of kinetic energy as strong intermolecular forces between the atoms prevent them from moving freely but instead vibrate constantly.
Liquids
Have constant volume but do not take a definite shape.
More kinetic energy than solids as intermolecular forces are weaker allowing for limited movement. Take shape of container.
Gases
Does not have a definite shape or volume.
Highest amount of kinetic energy due to weakest intermolecular forces and moving freely.
Carbohydrates
Source of energy for cell respiration. All carbohydrates contain carbon, hydrogen and oxygen.
Monosaccharides:
Hexose sugar - Glucose (most important energy source for cells) fructose and galactose (converted to glucose by the liver).
Pentose sugar - Deoxyribose (part of DNA) Ribose (part of RNA, needed for protein synthesis within cells).
Disaccharides:
Two hexose sugars - sucrose, lactose and maltose (present in food digested to monosaccharides for energy).
Oligosaccharides:
few sugars of 3 to 20 monosaccharides (form self antigens on cell membranes; important for immune system to distinguish self from pathogens). Produced by cells of mammary glands to encourage growth of beneficial bacteria in the infant’s intestinal tract.
Polysaccharides:
many (thousands) sugars
Starches - branched chains of glucose molecules (found in plants and broken down to monosaccharides).
glycogen - highly branched chains of glucose molecules (storage form of excess glucose in the liver and skeletal muscles).
cellulose - straight chains of glucose molecules (part of plant cell walls; provides fiber to promote peristalsis, especially by the colon, and to nourish microbiota).
Saccharides means sugar, prefix determines the amount.
Lipids
Contain elements of carbon, hydrogen, oxygen and sometimes phosphorous. Three types include true fats, phospholipids, and steroids.
True fats (mono, di or triglyceride with fatty acid molecules bonded to a glycerol molecule) are storage form for excess food molecules in subcutaneous tissue. Also cushions organs such as eyes and kidneys.
Phospholipids (diglycerides with a phosphate group bonded to the glycerol molecule) are parts of cell membranes and form myelin sheathes.
Steroids (cholesterol) (four carbon-hydrogen rings) are part of cell membranes and convert to vitamin D in the skin on exposure to UV rays. Converted by liver to bile salts to emulsify fat during digestion. Precursor for estrogen and testosterone.
Fatty acids in true fats may be saturated or unsaturated. Hydrogenating unsaturated fats for taste or texture with trans fats may clog arteries.
Proteins
Made up of amino acids that contain elements carbon, hydrogen, oxygen and nitrogen. Some contain sulfur.
Structural proteins:
Form channels, transporters, intercellular junctions, and receptor sites in cell membranes. Keratin - part of hair, nails, and the epidermis of the skin. Collagen - part of tendons, ligaments, and the dermis of the skin.
Hormones:
Insulin - enables cells to take in glucose; lowers blood glucose level. Growth hormone - increases protein synthesis and cell division.
Hemoglobin:
Enables red blood cells to carry oxygen.
Myoglobin:
Stores oxygen in muscle cells.
Antibodies:
Produced by lymphocytes (white blood cells), label pathogens for destructions.
Myosin and actin:
Muscle structure and contraction. Part of the cytoskeleton that gives shapes to cells and permits movement
Enzymes:
Catalyze reactions - synthesis, decomposition, energy production, cellular reproduction
