Chapter 2- Chemistry comes alive Flashcards
Molecule
the combination of two or more atoms of the same element (oxygen)
Compound
the combination of two or more atoms of different elements
Mixtures
any substance containing two or more compounds physically intermixed
Solutions
homogeneous mixtures can exist as solid, liquid, or gas composed of very small particles that do not settle out
Solvent
A dissolving medium, water is the body’s primary solvent
Solute
dissolved in solvent
Example- saline solutions (water and NaCl)
2 ways to describe concentration
- Percent solution- amount of solute is expressed as a percentage of the total solution volume
- Molarity- the number of moles of a substance per liter of solution
A mole of any element or compound is equal to
Its molecular weight
Colloids
heterogeneous mixtures (not evenly distributed) composed of large solute particles that do not settle out. Can undergo sol-gel transformation
Heterogeneous mixtures
Mixtures that are not evenly distributed
sol-gel transformation
mixture can change from a fluid state to a more solid state (and back again)
Ex- cytosol of cells changes consistency depending on certain cell activities (cellular division, change in shape)
Suspensions
heterogeneous mixture composed of large solute particles that do settle out
Ex- blood contains a fluid portion (plasma) with various cell types (RBC, WBC, and platelets) suspended in it
Chemical bonds occur when
substances are held together by attraction to each other or sharing or exchanging electrons
Types of chemical bonds (3)
- Ionic
- Covalent
- Hydrogen
Ionic bonds
transfer of electrons such that ions are formed, forms salts. Results in anions and cations
Anions
accept electrons, became negatively charged
Cations
donate electrons, become more positively charged
Covalent bonds
sharing of electrons in a common orbital between atoms, results in nonpolar and polar molecules
Nonpolar molecules
atoms in the covalent bond share electrons equally and are electrically balanced (carbon dioxide)
Polar molecules
atoms in a covalent bond do not share electrons equally, with one atom being an “electron hog”. Ex- oxygen strongly attracts electrons in water
Hydrogen bonds
occur when a hydrogen atom that is already covalently bonded to another atom is attracted by another electron hungry atom. Too weak to form molecules but can be structurally important
Example- oxygen in water pulls hydrogen from another water molecule- this forms surface tension
How are hydrogen bonds important for proteins?
water forms a shield between charged proteins so they won’t interact unnecessarily
Chemical reactions occur when
chemical bonds are formed, broken, or rearranged
Types of reactions (2)
- Synthesis
2. Decomposition
Synthesis reactions
formation of bonds between atoms or molecules to form larger, more complex structures. They are endergonic. Ex: anabolic reactions in the body
Endergonic
contains more energy after formation
Decomposition reactions
bonds are broken to create smaller molecules or individual atoms. They are mostly exergonic. Ex- catabolic reactions in the body
Exergonic
release energy when the bond is broken
Examples of inorganic compounds in the body (3)
- Water
- Salts
- Acids and bases
Importance of water in homeostasis (5)
- Universal solvent
- Heat capacity is high
- Protection
- Heat of vaporization is high
- Reactive in chemical reactions
What substances does water transport?
Water carries nutrients, respiratory gases, and waste as solutes
Why is water’s high heat capacity important?
Water can absorb and release large amounts of heat with little change to its own temperature
Importance- prevents overheating from exercise, sun exposure, etc.
How does water protect internal organs?
Water based body fluids provide a cushion for internal organs, preventing damage
Why is water’s high heat of vaporization important?
Large amounts of heat must be absorbed to break bonds and cause evaporation, sweat is extremely effective in cooling the body
Why is water’s reactivity important?
Hydrolysis reaction vs dehydration synthesis- chemical reactions will stop with little/no water availability
Purpose of salts
Salts dissociate in solution to form electrolytes. Electrolytes Na+ and K+ allow for muscle contraction and transmission of nerve impulses, iron used to carry oxygen, etc
Purpose of acids and bases
Acids and bases also form electrolytes. Many chemical reactions in the body take place at a certain pH, range is optimal between 7.2-7.4
Acids
release H+ ions in solution, causes pH to drop
Bases
release OH- ions in solution, causes pH to increase
Buffers
Weak acids release some but not all H+ when pH becomes too basic
Weak bases tie up excess H+ when pH becomes too acidic
Results- buffers prevent large changes in pH that could cause excessive damage in the body. high/low pH disrupts cellular activity
What could cause changes in pH?
Very acidic diet, respiratory issues
Carbon
Organic molecules found in the body contain carbon
Carbon is electroneutral- it neither gains nor loses electrons, can form molecules of various shapes (and therefore functions), all have specific functions in the body
Macromolecules
polymers that are made up of several smaller, identical subunits called monomers
Dehydration synthesis
Macromolecule formation involves dehydration synthesis
H from one monomer and OH from second molecule removed
Results- monomers form a covalent bond, water is released at the site of bond formation
Hydrolysis
Macromolecule breakdown involves hydrolysis
Water is added to break covalent bonds between monomers
Types of macromolecules (4)
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
Carbohydrate monomer
monosaccharide. They can form disaccharides, polysaccharides
Which carbohydrate molecules must be hydrolyzed to be used by cells?
Disaccharides and larger molecules must be hydrolyzed to be used by cells
Carbohydrates molecular formula
Formula: CH2O
Ex- glucose is C6H12O6
Major functions of carbohydrates (3)
- Fast and easy to use energy source
- Cell-cell interactions- carbohydrates attached to cell surface, used to communicate
- Structural (very small amount)
Types of lipids (3)
- Triglycerides
- Phospholipids
- Steroid
Triglycerides monomer
monomer is fatty acids and glycerol
Types of triglycerides (4)
- Saturated
- Unsaturated
- Trans fat
- Omega 3 fatty acids
Saturated triglycerides
contain only single covalent bonds, molecules packed closely together (fat found in meat products). Tend to be more solid in bloodstream and attach to other saturated fats, can block arteries over time
Unsaturated triglycerides
contain one or more double covalent bonds, molecules more spread out (plant based oils)
Trans fats
oil fats that have a H added at sites of double bonds (cookies, donuts). The worst fats
Omega 3 fatty acids
oil fat found in cold water fish
Krill fish, fish oil capsules
Triglyceride functions (3)
protection, insulation, fast and easily accessible energy storage
Phospholipids
modified triglycerides with 2 fatty acid chains and a phosphate group
Fatty acid chains are hydrophobic
Phosphate head is hydrophilic
Phospholipids function
used to build cell membranes (phospholipid bilayer)
What is the most important steroid for life?
Cholesterol
How is cholesterol ingested?
Ingested in eggs, meat, cheese
What organ produces cholesterol?
The liver
Major functions of cholesterol (2)
- structural component of cell membranes
2. “base” used by the body to form other steroids (steroid hormones- testosterone, estrogen, as well as corticosteroids)
Protein monomer
Amino acids
How are amino acids linked?
Peptide bonds
What determines protein function?
Sequence in which amino acids are ordered leads to large variety of protein functions, and the structure pf the protein itself will determine its function
Fibrous proteins
form long strands that can link together to form long, stable structures
Provide mechanical support and tensile strength, some contractile ability, ex: collagen, muscle
Globular proteins
compact, spherical shape
Chemically active
Transport molecules, immune defenses, regulation of growth and development, etc
Enzymes
biological catalysts that lower the activation energy of chemical reactions
They have varying degrees of specificity- some only catalyze one reaction, others can catalyze multiple reactions
What would happen without enzymes?
Without enzymes, most reactions in the body would either not occur or would occur too slowly to sustain life
Nucleic acids monomer
Nucleotides
DNA structure
Double stranded structure with pentose sugar deoxyribose
Bases: adenine (A), guanine (G), thymine (T), and cytosine (C)
Replicates itself prior to cell division- all resulting cells carry same genetic information
DNA function
stores genetic information in the form of genes (or genome) in the nucleus of the cell
RNA structure
Single stranded structure with sugar ribose
Bases: adenine (A), Guanine (G), cytosine (C), and uracil (U)
RNA function
uses instructions from DNA for protein synthesis
ATP
Adenosine triphosphate is the energy transferring molecule of any body cell
ATP structure
ATP has a triphosphate tail that has high bond energy
When 1 of the 3 phosphate tails is transferred to another molecule, that molecule temporarily has more energy to do work. While doing work, the molecule loses the phosphate group
ATP can be replenished by
adding a phosphate group to adenosine diphosphate (ADP)
What would happen without ATP
chemical reactions stop, cell transport stops, muscles cannot contract, and death occurs
What energy is used for ATP synthesis?
Energy released by glucose catabolism is used for ATP synthesis
A cell will only produce the amount of energy it needs for
Its reactions. This saves energy and saves space
