Biochemistry Flashcards
Define Cohesion vs Adhesion
Cohesion: molecules bonding to each other (H20-> H20)
Adhesion: molecules bonding to other substances (H20->CO2)
What type of molecule is water? How does it bond to other water molecules?
Water is Polar Covalent. It bonds to other water molecules through hydrogen bonding (dipole-dipole)
Define surface tension. Describe how hydrogen bonds affect surface tension.
Surface tension: the ability of a substance to withstand external force. The stronger the intermolecular force (eg. hydrogen bonds, in terms of water) the higher the surface tension.
How does water’s surface tension change when a nonpolar substance is added? (eg. soap, oil)
Surface tension LOWERS, hydrogen bonds are broken. Water becomes less cohesive.
Give one example (NOT the nickel) of the cohesive and adhesive properties of water.
Transpiration in plants: water clings to and moves through the xylem and phloem.
How do you identify an alcohol?
Hydroxyl group (OH) attached to a carbon chain.
How do you identify an aldehyde?
A carbonyl group (carbon doubled bonded to O, single bond to H)
How do you identify a ketone?
Carbon double bonded to O.
How do you identify a carboxylic acid?
A carboxyl group (carbon double bond to O, single bond to OH)
How do you identify an amine?
An amino group (N bonded once to 2 separate H, NH2)
How do you identify an amide?
Carbon, double bond to O, single bond to NH2.
What element is the building block of life?
Carbon
How many bonds can carbon have?
Four.
A biological catalyst is also called an _________
Enzyme.
In biology, useful molecules must be ________ so they can be carried around by __________.
Polar, water.
Define STRUCTURAL Isomer
A compound that has the same number of the same atoms (eg. 4 carbon) bonded in a different arrangement.
Define a GEOMETRIC isomer.
A molecule that has the same atoms, but varies in arrangement around a double bond. Will produce either a cis-isomer or a trans-isomer, depending on if the functional groups are on the same side or opposites
Define a polymer. What are polymers made of?
A polymer is a very large molecule consisting of smaller repeating subunits, called monomer. (eg. Starch is a polymer, but glucose is a monomer)
What is the difference between alpha and beta glucose?
Alpha glucose is a cis-isomer (hydroxyl groups), beta glucose is a trans-isomer.
What do glucose molecules join to form in PLANTS?
Alpha-glucose —> starch
Beta-glucose —> cellulose
What do glucose molecules join to form in ANIMALS?
Alpha-glucose—> glycogen (food storage)
Define Cellulose.
Major structural material of all plants, straight and tightly packed chains. Cannot be digested. Made of beta-glucose.
Define starch.
Stores energy. Forms branched chains. Can be digested, made of alpha-glucose.
Give two examples of Monosaccharides (not alpha or beta).
Galactose - sugar in milk.
Fructose - sugar in honey.
Give three examples of disaccharides.
Maltose, lactose, sucrose.
Give four examples of polysaccharides.
Glycogen, starch, cellulose, chitin.
The link between two glucose molecules is called a ______.
Glycosidic link.
Name the four isomers of C6H12O6
Alpha-glucose, beta-glucose, fructose, galactose.
Define an OPTICAL isomer
An isomer that is a non-superimposed mirror image of itself around its center.
Proteins are ______, and Amino Acids are ________.
Polymers, monomers.
How many amino acids are there in the human body? Which is the simplest?
20 different amino acids, and glycine is the simplest.
What TWO functional groups do every single amino acid contain?
Carboxyl group (double bond to O, single bond to OH) and an amino group (NH2).
When two amino acids join together, they form a _______ and connect through a _________.
Dipeptide, peptide bond.
What type of reaction forms dipeptides? Are there any byproducts?
Condensation reaction, water byproduct.
Name the four functions of proteins.
- Biological catalysts (enzymes)
- Provide structure (eg. Muscle, skin)
- Cell signalling/recognition
- Molecules of immunity
What is the structural difference between saturated and unsaturated lipids?
Saturated - full of hydrogen bonds
Unsaturated - not full of hydrogen (due to double bonds)
Name one properties of saturated fatty acids and why it behaves as such
Solid at room temperatures, because the straight molecular chains can pack tightly together.
Name one property of unsaturated fatty acids and why they behave as such.
Liquid at room temperature, as the bent chain cannot pack tightly.
What type of lipid is the major component of all cell membranes?
Phospholipids
What are the two types of nucleic acid?
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Lactose is made from which two isomers of glucose?
Alpha-glucose and galactose.
Sucrose is made from which two isomers of glucose?
Alpha-glucose and fructose.
Maltose is made from which two isomers of glucose?
Alpha-glucose and alpha-glucose.
A triglyceride is made up of what?
A glycerol and three fatty acids.
How does the structure of a phospholipid differ from a triglyceride?
Triglyceride: glycerol + 3 fatty acids
Phospholipid: glycerol + 2 fatty acids + phosphorus
What are the three essential parts of a nucleotide?
A phosphate group, a (pentose) sugar, and a nitrogenous base.
What is the chemical formula of maltose and why is it unusual?
C12H22O11 - double glucose, but missing two hydrogen and one oxygen because water is released (H2O).
What type of bond is it when the sugar of one nucleotide bonds with the phosphate of another?
A (polar) covalent bond.
When creating a helix structure, what type of bond occurs between two nucleotides’ nitrogenous bases?
Hydrogen bond
What are the 2 difference between DNA’s structure and RNA’s structure?
Strands: DNA is double-stranded, RNA is single-stranded
Sugar: DNA’s pentose sugar is deoxyribose, RNA’s pentose sugar is ribose.
Define oligosaccharide.
Carbohydrates that contain between two and ten monosaccharides, and may contain any of the four glucose isomers.
The four common carbohydrate polymers are starch, cellulose, glycogen, and chitin. For each, where are they found, how are they made, and what is their use?
Starch: plants, alpha-glucose, stores energy.
Cellulose: plants, beta-glucose, structural integrity
Glycogen: animals, glucose monosaccharides, glucose storage
Chitin: mainly fungi, fructose/galactose, strength within cellular structures
What makes a complete protein?
Contains the nine amino acids the human body cannot produce.
Glycogen, a polysaccharide, is used to store glucose. What makes its structure so unique?
It is branched, like a tree’s root web, to allow for higher water solubility.
Fructose is WHAT TYPE of isomer?
Structural.
Enzymes are named very simply. For example, the enzyme that processes lactose is called ________, the enzyme that processes maltose is called ______.
Lactase, maltase.
Enzymes _______ the activation energy of a reaction, _____________ the speed of the process.
Decrease, increasing
Describe an enzyme’s primary structure.
Hundreds or thousands of amino acid chains, forming peptide bonds (amino end of one to the hydroxyl end of another) and becoming polypeptides
Describe an enzyme’s secondary structure
Folding of the polypeptide into spirals or pleated sheets. Caused by HYDROGEN BONDS, forming between carbonyl and amine groups on the amino acids.
Describe the tertiary structure of an enzyme
Defines the overall 3D shape, based on interactions between side groups of the peptide chain (hydrogen or disulfide bonds).
Describe the quaternary structure of an enzyme
When two or more polypeptides join together to form a folded, globular protein. Held together through hydrogen bonding.
Name and define the three types of enzyme inhibition.
Competitive: bonds to active site.
Non-competitive: bonds to allosteric site, changes shape of enzyme
Non-specific: causes changes to denature enzymes (heat, pH)
Describe the structure of a phospholipid and name where it is found.
Phosphate ‘head’ (attracted to water) and fatty acid ‘tail’ (repelled from water). Found in the cell membrane - phospholipid bilayer!
Name the four main membrane components and their function
Cholesterol: maintains fluidity, spaces out phospholipids
Integral proteins: act as channels for large molecules
Peripheral proteins: protein marker, identify receptors on the membrane
Glycolipids/proteins: interactions w other cells, signalling within the cell.
Define active vs passive transport
Active transport requires ATP (energy) - molecules move against a concentration gradient. Passive transport requires no energy, moves with the gradient.
Define solute vs solvent.
Solute: molecule that can dissolve.
Solvent: liquid that can dissolve molecules.
What are the three types of passive transport?
Diffusion, facilitated diffusion, and osmosis.
Isotonic vs hypotonic vs hypertonic OSMOTIC SOLUTIONS
Isotonic - same amount of solute/water inside/outside the cell.
Hypotonic - less solute, more water OUTSIDE
hypertonic - more solute, less water OUTSIDE
