Unit 1 (Biochemistry) - Chapter 1 Flashcards
What functional groups make up the fatty acids?
hydroxyl and carboxyl
What is a complex carbohydrate? Provide examples of the two types.
(1.4)
○ a molecule that is composed of hundreds to thousands of monosaccharides linked together
○ Some complex carbohydrates are important for energy storage in cells, while others are essential for structural support
Examples:
storage - starch and glycogen
structural - cellulose and chitin
What are the 5 main categories of lipids?
(1.4)
fatty acids, fats, phospholipids steroids and waxes
What are the two major biochemical roles of carbohydrates?
(1.4)
○ Energy and Digestion.
- Most types of carbohydrates, such as starch and sugar, break down into glucose
- which is the simplest form of carbohydrate and your body’s primary source of energy.
What is a fat?
(1.4)
A fat is a lipid that is made from two types of molecules: fatty acid and a glycerol molecule
What is polarity?
(1.1)
○ partial positive or negative charge at ends of a molecule
What are unsaturated fats?
(1.4)
○ a lipid that is composed of unsaturated fatty acids with double bonds in their hydrocarbon chain
○ generally referred to as oils
○ Liquid at room temperature
What is the structure of a triglyceride?
a fat; three fatty acid chains linked to a glycerol molecule through dehydration synthesis
What are all the functions of Carbohydrates?
(1.4)
○ energy sources for the body
○ structural support
○ cell to cell communication
○ raw material to build amino acids, lipids and nucleic acids
○ performs many complex functions in cells
What is a polar covalent bond? (1.1)
(1.4)
○ a bond between two atoms, made up of unequally shared electrons
Distinguish among: monosaccharides, disaccharides, oligosaccharides and polysaccharides in terms of structure. State examples.
(1.4)
○ Monosaccharides:
are the simplest form of carbohydrates consisting of a single sugar unit
- E.g. glucose, fructose and galactose
○ Disaccharides are a carbohydrate molecule that is made from two sugars covalently bonded monosaccharide units joined together by a dehydration synthesis reaction
- E.g. maple syrup, lactose, sucrose
○ Oligosaccharides is a term used to describe carbohydrates consisting of a small number of monosaccharides with a carbon number of 2-10 (including disaccharides)
- E.g. sucrose, lactose and maltose
○ Polysaccharides are a complex carbohydrate that contains many sugars covalently attached
- E.g. cellulose, plant starches, glycogen, etc.
○ Very polar and hydrophilic, however cannot dissolve in water
What is polymerization? (1.4)
○ a process in which small subunits called monomers are linked to form a polymer (a larger molecule)
What are lipids? (1.4)
○ a non-polar compound that is mostly made of carbon and hydrogen
○ they do not dissolve in water
What is a carbohydrate?
(1.4)
○ A biomolecule that consists of carbon, hydrogen and oxygen
○ Plays a role in structural support and cell-to-cell communication
What is a complex carbohydrate? (1.4)
○ a molecule that is composed of hundreds to thousands of monosaccharides linked together
○ Some complex carbohydrates are important for energy storage in cells, while others are essential for structural support
Examples:
storage - starch and glycogen
strucutral - cellulose amd chiin
What is Cellulose? What is its structure and functions?
(1.4)
- The main component of plant cell walls and the most organic molecule on Earth
- Cellulose molecules are long and straight and have very large number of polar OH groups)
What are the three functional groups associated with carbohydrates?
(1.4)
hydroxyl, aldehyde and ketone
Under what conditions is a fatty acid said to be saturated? Unsaturated?
(1.4)
- Saturated - If all the carbons are linked to each other with single bonds
- Unsaturated - double bonds
a) Why are unsaturated fats liquid at room temperature?
b) Why are saturated fats solid at room temperature?
(1.4)
a) Unsaturated fats have a kink in their molecule (because of the double bond), causing it to bend, which means that they cannot be as tightly packed as saturated fats
b) Saturated fats are solids because their chains are long and straight and can be packed closely together to form a solid structure at room temp.
Identify the general structure of a carbohydrate in terms of elements and generic formula.
(1.4)
○ Elements: Carbon, Hydrogen,
Oxygen
○ General Formula: (CH2O)n
Distinguish between monomers, polymers and oligomers
○ Monomers are small molecules that can bind chemically to other molecules, single units
- e.g. nucleotides, polypropene, etc.
○ Polymers are large molecules that are covalently bonded to monomers
- e.g. DNA, nylon, polyethylene, etc.
○ Oligomers are 2-10 monomers covalently bonded
- e.g. acrylic, polyester
What are saturated fats?
(1.4)
○ a lipid that is composed of saturated fatty acids with single bonds in their hydrocarbon chain
○ fats that are obtained from animals such as butter or lard
What are fatty acids? (1.4)
a molecule that consists of a carboxyl group and a hydrocarbon chain
What is a glycosidic bond? (1.4)
○ a bond between two monosaccharides ‘
○ Linkages are designated as alpha or beta
a) What is a phospholipid?
b) Name the three components of a phospholipid.
(1.4)
a) ○ A lipid that consists of two fatty acids and a phopshate
group bound to glycerol (the backbone of the
molecules).
○ Makes up the lipid bilayer of cell membranes
b) a polar head (which includes a phosphate group), glycerol, and a hydrocarbon chain
a) What are steroids?
b) What are sterols?
c) What are the general function of steroids?
(1.4)
a) ○ Steroids are lipids composed of four fused carbon rings.
b) ○ Sterols are a subgroup of steroids and are the most abundant steroids.
c) ○ signal molecules – hormones
○ cholesterol in cell membranes
○ vitamins (e.g. D2)
What are aldoses? What are ketoses? Distinguish between them.
(1.4)
○ Aldoses are a sugar containing aldehyde group (e.g. glucose)
○ Ketoses are a sugar containing a ketone group (e.g. fructose)
What is the difference between glucose and galactose? What term is given to these kinds of molecules?
(1.4)
○ Glucose has OH on the left side of C-3
○ Galactose has OH on the left side of C-3 and C-4
○ They both have a molecular formula of C6H12O6, which means they are isomers.
- They have the same formula but different structural arrangement.
a) What are waxes?
b) How are waxes used in nature?
a) ○ Long fatty acid chains linked to alcohols or carbon rings.
○ Hydrophobic, extremely non-polar and soft solids over
a wide range of temperatures
b) ○ flexible waterproof coatings on vrious plant and animals parts
○ feathers - aquatic birds can float
○ leaves - waxy cuticle slows water loss by transpiration
○ barrier to infection by bacteria and viruses
○ barrier to insect attack
○ beeswax to make honeycombs
What is an α-glucose molecule? What is a β-glucose molecule? What are the biological roles of these two molecules?
○ When glucose forms a ring, there are two possible arrangements of the -OH group, which is bound to carbon at position 1 (C-1)
○ For plants to store sugar, they need chains of alpha glucose to build starch.
○ For plants to build structural material, they need chains of beta glucose to create cellulose.
List the functions of lipids.
(1.4)
- energy storage
- structure of cell membrane
- chemical signaling molecules
- thermal insulation
- solubilizing vitamins A,D,E,K for ingestion
- water repellant
What is meant by the term esterification?
Esterification is the formation of an ester linkage between a hydroxyl group on one molecule and a carboxyl group on another molecule by the removal of a water molecule.
Why are lipids used for energy storage in living organisms?
(1.4)
High chemical energy per gram which is more than 2 times
that of carbohydrates
What is a protein?
(1.5)
A large molecule that consists of many amino acid subunits joined together by polypeptide bonds and folded into a 3-D structure that specifies its function
What are nucleic acids?
(1.5)
A blueprint for proteins that are produced in cells, carries genetic information
What monomer makes up a protein?
(1.5)
Amino acids.
What are essential amino acids?
(1.5)
Amino acids that can only be obtained from nutrients
a) What is a peptide?
b) What is a polypeptide?
c) What is a peptide bond?
(1.5)
○ peptide: a chain of amino acid subunits which are
connected by peptide bonds.
○ polypeptide: a peptide with more than 50 a.a.’s
○ peptide bond (amide linkage): a covalent bond that links
amino acids. Formed by interaction of amine group on one
amino acid and a carboxyl group on another amino acid. Water is removed by dehydration synthesis.
What determines the shape of a protein?
(1.5)
The primary structure of a protein — its amino acid sequence — drives the folding and intramolecular bonding of the linear amino acid chain, which ultimately determines the protein’s unique 3D shape
What functional groups does an amino acid contain?
(1.5)
A carboxyl group and an amino group
What are the general biological functions of proteins?
(1.5)
○ Providing your body with a structural framework
○ Fighting infections
○ Transporting materials in our body
○ Allowing metabolic reactions to take place
○ Maintaining proper pH and fluid balance
○ Helping repair and build our body’s tissues
Describe the bonding and the components of a disulfide bridge
(1.5)
○ Disulfide bridges are sometimes called disulfide bonds or S-S bonds
○ They are covalent links between the sulfur atoms of two cysteine amino acids and their formation stabilizes the tertiary and higher order structure of proteins.
Describe how a polypeptide chain is formed. What type of bond forms between adjacent amino acids?
(1.5)
Linking amino acids through a dehydration synthesis reaction, creating a polypeptide bond
Describe the 4 structures of a protein
(1.5)
Primary Structure - sequence of amino acids in a chain
Secondary Structure - the primary structure coiled or folded by hydrogen bonds into either:
a) alpha-helix: R groups point outward
b) beta-pleated sheet: H-bonds between
N-H of one chain and C = O of another chain
Tertiary structure - secondary structure folding upon itself to make a globular protein
Quaternary Structure - multiple polypeptide chains bonded together
What is a prosthetic group? Give an example.
(1.5)
○ Non-protein components that many proteins require to function
○ One example is heme in hemoglobin
What is meant by denaturation and how can it be dangerous?
(1.5)
○ Loss of both structure and function of a protein through factors such as temperature, pH, ionic interference
What is a nucleotide?
(1.5)
The building block of nucleic acids; consists of a 5-C sugar, a nitrogenous base and one to three phosphate groups
Distinguish between purines and pyrimidines.
(1.5)
○ Pyrimidine bases are single organic rings (uracil, thymine, cytosine)
○ Purine bases are two-ringed organinc structure (adenine, guanine)
What is a phosphodiester bond?
(1.5)
a link that is formed between nucleotides by a phosphate bridge
What is an enzyme?
(1.7)
A biological catalyst, usually a protein, that speeds up a chemical reaction without being consumed in the reaction
What is a substrate?
(1.7)
A substance that is recognized by and binds to an enzyme
What is an active site of an enzyme?
(1.7)
A pocket or groove in an enzyme that binds its substrate
Describe the catalytic cycle of enzymes
(1.7)
- Substrate enters the active site of the enzyme
which helps orient the substrate molecule(s). An enzyme-substrate complex is formed. - Enzyme changes shape slightly – this is called
“induced fit” - Shape change allows bonds to form or break in the
substrate. - Product(s) are released from the active site.
- Enzyme returns to original shape; thus, is
unchanged and can go to catalyze another reaction
What is the induced-fit model?
(1.7)
a model of enzyme activity that describes how an enzyme changes shape to better accommodate a substrate
a) What are cofactors?
b) What are coenzymes?
(1.7)
a) Product(s) are released from the active site.
- Enzyme returns to original shape; thus, is
unchanged and can go to catalyze another reaction
b) Coenzymes are organic molecules that act as
cofactors.
What factors can modify enzyme activity?
(1.7)
- enzyme and substrate concentration - will influence the rate of the catalysis reaction
- temperature
- pH
a) What do enzyme inhibitors do?
b) Distinguish between competititve inhibition and non-competitive inhibition
(1.7)
a) - They lower the rate at which an
enzyme catalyzes a reaction.
b)
- Competitive inhibition - a situation in which a competitor substance binds to a normal substrate binding site to block enzyme activity. Note: Competitive inhibition is reversible if excess substrate is available.
- Non-competitive inhibition - a situation in which molecules bind to an enzyme at a site that is not the ative site, thus blocking enzyme activity.
What is an allosteric site? What is allosteric regulation?
(1.7)
- An allosteric site is a binding site on an enzyme that binds regulatory molecules (but is not the active site).
- Allosteric regulation is the regulation of one site of a protein by binding to another site on the same protein
What is feedback inhibition?
(1.7)
- the regulation of a pathway by one of the products of this pathway
- it prevents cellular resources from being wasted in the synthesis of molecules at intermediate steps in the pathway
What is the enzyme’s temperature limit?
(1.7)
Around 40 degrees celsius
