Unit One Flashcards
Hydrogen bonds
Bonds between hydrogen and f/o/n of another molecule, strongest intermolecular force but weaker than intramolecular forces, give water its special properties
Bonds between different water molecules
Polar covalent bonds
When atoms of a molecule have an unequal sharing of electrons resulting in partial negative and partial positive charges
Bonds between hydrogen and oxygen of water molecules
Polarity
Unequal distribution of electrons resulting in partial positive and partial negative charges
Hydrophilic
Water loving, soluble in water, because soluble in water usually means polar
Hydrophobic
Insoluble in water, nonpolar generally because water dissolves polar things
Cohesion
The tendency of molecules to stick together, forces of attraction between molecules of the same substance
Adhesion
The clinging of one substance to another, forces of attraction between molecules of different substances
Surface tension
A measure of how difficult it is to stretch or break the surface of a liquid, how much energy it requires to expand the surface area of a liquid
Heat storage capacity
Heat is the a,punt of energy associated with the movement of atoms and molecules in a body of matter
Temperature is the intensity of heat aka the average speed of molecules rather than the total amount of heat energy
Heat storage capacity is how much heat can be absorbed without the molecule breaking apart aka basically specific heat
pH
pH stands for the potential of hydrogen, the pH scale describes how acidic or basic a solution is, 0 is most acidic, 7 is neutral, 14 is most basic, each increase by one in the scale means a decrease by the power of ten in the acidity
Acid
A compound that donates hydrogen ions to solutions, ex. HCl, acidic solutions have higher concentrations of H+ than OH-
Base
A compound that accepts hydrogen ions and removed them from solution ex. NaOH, have a higher OH- concentration than H+, basic solutions are also called alkaline
Buffer
Stabilizes the pH, minimizes changes in pH, both an H+ acceptor and donor, important in our blood because they keep it at the right pH so we don’t die.
Organic compounds
Carbon-based molecules
Isomers
Compounds with the same formula but different structures
Functional group
The first five chemical groups important in the chemistry of life, they affect a molecule’s function by participating in chemical reactions in characteristic ways, they are polar and hydrophilic, large role in water-based life
Carboxyl group
Consists of carbon double bonded to an oxygen and also bonded to a hydroxyl group. Acts as an acid by contributing an H+ to a solution and becoming ionized. Compounds with carboxyl groups are called carboxylic acids
Dehydration synthesis
Cells link monomers together to form polymers by dehydration synthesis. The reaction removes a molecule of water and combines two monomers. H+ and OH- combine and form water, covalent bond forms between the monomers too.
Hydrolysis
The reverse of dehydration synthesis, cells break bonds between monomers by adding water to them, monomers absorb water and break apart
Carbohydrates
A class of molecules ranging from the small sugar molecules dissolved in soft drinks to large polysaccharides like the swerve molecules we consume in pasta and potatoes
One monomer looks like a hexagon
Monosaccharides make up polysaccharides
Almost all are hydrophilic because of the many hydroxyl groups attached to their sugar monomers
Functions of carbohydrates
Energy source
Structure (mostly for plants)
Monosaccharides give energy
Polysaccharides store energy (starch in plants, glycogen in animals) and give structure (cellulose in plants)
Monosaccharides
The carbohydrate monomers, single unit sugars. Can be hooked together by dehydration synthesis to form more complex sugars and polysaccharides, generally have molecular formulas that are some multiple of CH2O.
Main fuel molecules for cellular work, their carbon skeletons are used as raw material for making other kinds of organic molecules
Disaccharides
Cells make disaccharides from two monosaccharides by dehydration synthesis, most common disaccharide is sucrose
Polysaccharides
Polymers of monosaccharides linked together by dehydration synthesis. May function as storage molecules or as structural compounds.
Macromolecules
Four main classes of large biological molecules are carbohydrates, lipids, proteins, and nucleic acids, on a molecular scale many of these are gigantic so they’re called macromolecules
Polymers
Cells make most of their large molecules by joining smaller molecules into chains called polymers. Long molecules consisting of many identical or similar building blocks strung together.
Monomers
Building blocks of polymers
Glycogen
A glucose polysaccharide, animals store excess sugar in the form of glycogen, more highly branched than starch, most of ours is stored in the liver and muscle, release glucose when needed
Starch
Storage polysaccharide in plants, consists entirely of glucose monomers. Coil into a helical shape, starch helix can be unbranded or branched, plants and animals need sugar for energy and as raw material for building other molecules, plant cells often contain starch granules from which they can withdraw glucose by hydrolysis
Cellulose
The most abundant organic compound on earth, forms cable like fibrils in the tough walls that enclose plant cells. Polymers of glucose, but glucose monomers linked together in a different orientation. Joined by hydrogen bonds, strong. Not a nutrient for humans, but helps digestive system health. Fiber.
Chitin
Structural polysaccharide, used by insects and crustaceans to build their exoskeleton, also found in the cell walls of fungi, humans use chitin to make a strong and flexible surgical thread that decomposes after a wound or incision heals
Lipids
Diverse compounds that are grouped together because they mix poorly, if at all, with water. Consist mainly of carbon and hydrogen atoms linked by nonpolar covalent bonds. Hydrophobic.
Fat
A large lipid made from two kinds of smaller molecules:glycerol and fatty acids
Structure and function of lipids
Glycerol bonded to three fatty acids
Stores energy
Makes up cell membranes
Glycerol
An alcohol with three carbons, each bearing a hydroxyl group.
Fatty acid
Consists of a carboxyl group and a hydrocarbon chain, usually 16 or 18 atoms in length, carbons in the chain are linked to each other and to hydrogen atoms by nonpolar covalent bonds, making the hydrocarbon chain hydrophobic
Proteins
A polymer constructed from amino acid monomers, each protein has a unique three dimensional structure that corresponds to a specific function, important to the structures of cells and organisms
Structure and function of proteins
Primary, secondary, tertiary, and quaternary structures, will discuss later
Control the rate of reactions, regulate cell process, form bones and muscles, transport substances in and out of cells, carry out many important functions especially through enzymes (speed up chemical reactions)
Amino acids
Only 20, all have an amino group and a carboxyl group, both covalent lot bonded to a central carbon atom called the alpha carbon. Also bonded to the alpha carbon is a hydrogen atom and a chemical group symbolized by the letter R. Can be hydrophilic or hydrophobic, join together to form polymers.
Peptide bonds
The covalent linkage between amino acids (have been joined together by dehydration synthesis)
Polypeptide
A chain of amino acids
Enzymes
The chemical catalysts that speed and regulate virtually all chemical reactions in cells
R-groups
Side chain, differs with each amino acid, can be simple or complex, basically just a chemical group bonded to the alpha carbon in an amino acid symbolized by the letter R
Primary structure
Sequence of amino acids, unique to a specific protein, determined by inherited genetic information
Secondary structure
Coils (alpha helix) or folds (pleats), parts of the polypeptide coil or fold into local patterns, coiling results in an alpha helix, folding leads to a pleated sheet. Hydrogen bonds.
Tertiary structure
3-D shape, globular or fibrous, results from interactions among the R groups
Quaternary structure
Multiple tertiary forms “connected”
Activation energy
The amount of energy it takes to get a reaction going, enzymes decrease this so they speed up the reactions
Substrate
A specific reactant that an enzyme acts on, fits into a region of the enzyme called the active site
Active site
Where the substrate fits into in an enzyme, a pocket or groove on the surface of the enzyme former by only a few of the enzyme’s amino acids
Competitive inhibitor
Resemble the enzyme’s normal substrate, can fit into active site, reduces an enzyme’s productivity by blocking substrates from entering the active site
Non competitive inhibitor
Does not enter the active site, binds to the enzyme somewhere else and its binding changes the shape of the enzyme so that the active site no longer fits the substrate
Denaturation
When polypeptide chains unravel, losing their specific shape, and as a result their function. Changes in salt concentration and pH can denature many proteins, as can excessive heat
Ideal conditions for enzymes
Room temperature substrate, greater surface area, high substrate concentration, neutral substrate
Main function of digestive system and four stages
Food processing
Ingestion, digestion, absorption, elimination
Ingestion
The act of eating
Digestion
The breaking down of food into molecules small enough for the body to absorb
Food is broken down first mechanically, then chemically
The chemical breakdown of food is done through the process of hydrolysis
Absorption
The cells lining the digestive tract absorb the small molecules
Elimination
Undigested material passes out of the digestive tract
Why do we need to eat
Food provides nutrients needed for survival
Water, vitamins, minerals, carbohydrates, proteins, fats
Why do we need water
Our body is ~70% water
The chemical reactions (hydrolysis and dehydration synthesis) needed for our body to stay alive occur in water
Why do we need fats
Lipids can be used as an energy source
Lipids provide insulation, cushioning, and make up cell membranes
Why do we need carbs
Complex carbohydrates (whole grains, starch) are broken down over time into simple sugars They are used to make ATP, the main source of energy in living things
Why do we need proteins
They are the structural material of our bodies
They are the functional molecules that keep us alive
Our bodies only make 12 out of the 20 amino acids
Digestive system
Consists of alimentary canal and accessory glands
Food is able to move through the alimentary canal by peristalsis
Peristalsis
Food is able to move through the alimentary canal by peristalsis
Alternating waves of contraction and relaxation of the smooth muscle lining the canal
Sphincters
Muscular ring-like valves that regulate the passage of food into and out of the stomach
Oral cavity
Site of mechanical digestion and beginning of chemical digestion
Chewing = more surface area
Salivary glands secrete saliva through ducts into the oral cavity
Saliva contains the enzyme amylase, which hydrolyzes starch
Amylase begins the chemical digestion of carbohydrates
Esophagus
After chewing, the tongue shapes food into a bolts and pushes it to the back of the oral cavity and into the pharynx, which opens up to both the trachea and the esophagus.
Epiglottis keeps food from going into lungs
Involuntary waves of contraction by the smooth muscles in the esophagus take over, peristalsis moves the bolts down through the esophagus into the stomach
Stomach
Stomach stores food and breaks food down with acid and enzymes (pH of 2, only work in optimal conditions)
Stomach secretes gastric juices from its gastric glands (long tubular pits lined with cells that secrete different substances)
Pepsin in the stomach begins the chemical digestion of proteins
More about the stomach
The activity of gastric glands is regulated by hormones
Taste/smell of food = gastric juices
Food in stomach = release of gastrin
Gastrin = gastric juices
Too much acid = inhibits release of gastrin
Chyme
An acidic, nutrient rich mixture of food and enzymes
Pyloric sphincter
Regulates the passage of chyme from the stomach to the small intestine
Small intestine
The rest of the digestion of molecules occurs in the small intestine
The nutrients that result from digestion are also absorbed here
The pancreas and liver contribute to digestion in the small intestine
The pancreas secretes pancreatic juice
The liver produces bile, which is stored in the gall bladder, then secreted into the small intestine
Why is bile important
Contains bile salts
Bile salts emulsify fats, making them more easily accessible to lipase
Small intestine
All four types of large macromolecules are digested in the small intestine Pancreatic amylase is carbs Bile salts and lipase in fats Nucleases is nucleic acids Other is proteins
More surface area
More absorption
Circular folds, villi and microvilli
Go to each other, microvilli is what absorbs the nutrients
Small intestine
Fatty acids and glycerol are absorbed by the epithelial cells, recombine into fats, then are transported into a lymph vessel
Amino acids and sugars pass through the int spinal epithelium and then across the thin wall of the capillaries, making their way into the blood stream
Nutrient rich blood then goes to the liver
Liver
Gets first access to the nutrients absorbed from a meal
Removes excess glucose from the blood and converts it to glycogen
Converts nutrients into new substances (ex. synthesizes proteins from amino acids)
Converts toxins into inactive products
Produces bile
Large intestine (aka colon)
Main function of the colon is to absorb excess water
About 7 liters of fluid enters the digestive tract each day, about 90% of this water is absorbed back into the blood and tissue fluid
As water is absorbed, the remains of digested food become more solid as thy move through the colon by peristalsis
Waste products, stored in rectum, elimination
Order of digestive system
Oral cavity, esophagus, stomach, small intestine, liver, large intestine
Three main accessory glands in the human digestive system
Salivary glands, pancreas (produces enzymes), and the liver
