Chapter 2 CMB Biomolecules Flashcards
What are biological molecules?
Cells that make a huge number of large molecules from a small set of molecules
What are the 4 main classes of biological molecules?
- Carbohydrates
- Proteins
- Lipids
- Nucleic Acids
What are the subclasses of carbohydrates? (3 types)
- Monosaccharides
- Disaccharides
- Polysaccharides
What are the subclasses of proteins? (3 types)
- Amino acids
- Polypeptides
- Enzymes
What are the subclasses of lipids? (4 types)
- Phospholipids
- Triacylglycerols (Triglycerides)
- Fatty acids (Saturated & Unsaturated)
- Steroids
What are the subclasses of nucleic acids? (2 types)
- Deoxy ribo Nucleic Acid (DNA)
- Ribo Nucleic Acid (RNA)
What are macromolecules?
Each class contains small molecules (monomers), joined together to make large molecules (polymers)
Is it true that macromolecules are covalently linked chains of building blocks?
Yes
How do cells produce macromolecules?
Cells produce macromolecules by linking together the ready-made building blocks (monomers)
What is the baby form (monomer) of carbohydrates?
Sugars
What is the baby form (monomer) of nucleic acids?
Nucleotides - A,T,G,C
What is the baby form (monomer) of proteins?
Amino acids
What is the baby form (monomer) of lipids?
Fatty acids
What are the biological roles of carbohydrates? (6 roles)
- Primary source of energy for cells
- Anticoagulant
- Antigen
- Hormones
- Framework of the body
- Backup energy source
What is anticoagulant?
A substance that prevents blood from clotting
What is antigen?
A substance that provokes the immune system so that it can generate antibodies
How are carbohydrates classified into? (3 types)
- Monosaccharides (Monomer)
- Disaccharides (Dimer)
- Polysaccharides (Oligomer/Polymer)
What are the properties of monosaccharides? (5 properties)
- Single sugar molecule
- Crystalline
- Sweet taste
- Soluble in water
- Easy to digest and absorbed in the body
What are examples of simple sugars, monosaccharides? (3 examples)
- Glucose
- Galactose
- Fructose
What are disaccahrides?
2 monosaccharides linked by 1 glycosidic bond
What are the key disaccharides to know? (3 types)
- Sucrose (Fructose + Glucose)
- Lactose (Galactose + Glucose)
- Maltose (Glucose + Glucose)
What are the properties of disaccharides? (5 properties)
- Combination of two monosaccharides
- Crystalline
- Sweet taste
- Water-soluble
- Must be broken down into monosaccharides before they can be absorbed in the body and used for energy
Recap Question
1. How many sugar molecules in monosaccharides and disaccharides?
2. What are the 3 most common monosaccharides and disaccharides?
- Monosaccharide = Single sugar molecule
Disaccharide = 2 sugar molecules combined - Monosaccharide (Glucose, Galactose, Fructose)
Disaccharide (Sucrose, Lactose, Maltose)
What is polysaccharide?
Polysaccharide are complex carbohydrates that have many monosaccharides that are linked together by glycosidic bonds
What are examples of polysaccharides? (4 examples)
- Glycogen
- Starch
- Cellulose
- Chitin
What polysaccharide can be found in animals?
Glycogen
What polysaccharide can be found in plants? (2 types)
Starch and Cellulose
What polysaccharide can be found in insects?
Chitin
What polysaccharides are for energy storage? (2 types)
Glycogen and Starch
What are branched structures?
Branched structures allows greater points of access by enzymes to act on it and break
What are long, unbranched chains?
Long, unbranched chains provide greater strength and are difficult to break
What is cellulose for?
Cellulose is for structural support in plants
What is chitin for?
Chitin makes up the exoskeleton in insects
Which structure is stronger and weaker? (unbranched, branched)
Stronger => Unbranched
Weaker => Branched
What are the properties of polysaccharides? (3 properties)
- Not sweet in taste
- Insoluble in water
- Do not form crystals
What are the two groups polysaccharide can be divided into?
Polysaccharides may be a homopolysaccharide or a heteropolysaccharide depending on their monosaccharide components
What does homopolysaccharide consist of?
A homopolysaccharide consists of same types of monosaccharide (glucose)
What does heteropolysacchride consist of?
A heteropolysaccharide consists of different types of monosaccharides (many glucose and fructose)
What are the biological roles of lipids? (4 roles)
- Form cell membrane around our cells
- Phopholipids, Sphingolipids and Cholesterol - Act as energy stores and are broken down to generate ATP (energy)
- Triacylglycerols (Fats, Triglycerides) - Hormones
- Steroids - Vitamins
What do phospholipids consist of?
1 glycerol + 2 fatty acid chains (hydrophobic tail) + 1 phosphate group (hydrophilic head)
What is hydrophilic and which group is it from?
Hydrophilic means likes water, and is from phosphate group
What is hydrophobic and which group is it from?
Hydrophobic means hates water, and is from fatty acid group
What do cell membranes mainly consist of?
Phospholipids
What are the two parts of phospholipids?
- Polar phosphate “head”
- Two non-polar fatty acid “tails”
What are some terms in the cell membrane? (9 examples)
- Glycoprotein
- Glycolipid
- Transmembrane protein
- Integral protein
- Peripheral protein
- Cholesterol
- Hydrophilic heads
- Hydrophobic tails
- Phospholipid bilayer
What is cholesterol?
Cholesterol is just another lipid found in the plasma membrane
Why is cholesterol an important part of a healthy body?
It is because cholesterol is used as part of the cell membranes, and also as part of some hormones
What is high level of cholesterol in the blood called and what does it lead to?
Hypercholesterolemia is a major risk factor for coronary heart disease, which can lead to heart attacks
Cholesterol like other fats cannot dissolve in the blood. How are they transported?
They have to be transported to and from the cells by special lipid carriers called lipoproteins
What are the two types of lipoproteins?
- Low Density Lipoprotein (LDL)
- High Density Lipoprotein (HDL)
What is a “Bad” cholesterol?
Low Density Lipoprotein (LDL)
What is a “Good” cholesterol?
High Density Lipoprotein (HDL)
What is Low Density Lipoprotein (LDL)?
The major cholesterol carried in the blood
What happens when a person has too much LDL cholesterol in the blood?
It can slowly build up within the walls of the arteries. together with other substances it can form plaque which clogs those arteries. This condition is known as arteriosclerosis (increase risk of heart attack)
What does a high LDL level mean?
It indicates that there is a greater risk of heart attack
What is High Density Lipoprotein (HDL)?
HDL removes excess cholesterol from arteriosclerosis plaques and thus slows their deposit
Why is HDL known as “good” cholesterol?
It is because a high level of HDL seems to protect against heart attack
What does a low HDL level mean?
It indicated that there is a greater risk of heart attack
What are triglycerides composed of?
It is made of 3 fatty acids + 1 glycerol
What are triglycerides known for?
It is the major energy store and also a major dietary lipid in humans
What are the properties of triglycerides? (3 properties)
- Insoluble in water (hydrophobic)
- Stored in specialized adipose (fat) cells
- Transported around the body in large lipid-protein particles called lipoproteins
What are two types of fatty acids?
- Saturated
- Unsaturated
What are fatty acids?
Fatty acids are the “building blocks of lipids”
What are the properties of a saturated fatty acid? (3 properties)
- “No double C-C bond”
- Molecules are more straight
- Fats: Solid at room temperature
What are the properties of a unsaturated fatty acid? (3 properties)
- Contains at least “1 C-C double bond”
- Causes “kinks” bends in molecules
- Liquid at room temperature
Why are saturated fats solid at room temperature?
Saturated fatty acids have straight chains and therefore saturated fats pack together tightly
Why are unsaturated fats liquid at room temperature?
Naturally occurring unsaturated fatty acids have a cis configuration at the double bonds and thus have a pronounced bent shape and therefore they cannot pack tightly
What is the difference between saturated fats and unsaturated fats? (3 differences)
- Saturated fats are solid at room temperature while unsaturated fats are liquid at room temperature
- Saturated fats contains single bond while unsaturated fats contains double bond
- Saturated fats have molecules that are straight while unsaturated fats have bends in molecules
How can steroids be recognized?
Can be recognized by 6 carbon and 5 carbon rings
What are steroids?
Steroids are chemical messengers
How are steroids classified?
Are classified as lipids die to their non-polar and hydrophobic natures
What are proteins?
Proteins are the building blocks of our body
What are the function of proteins? (4 functions)
- Contribute to cell growth, maintenance and repair
- Acts as enzymes and hormones
- Help maintain a strong immune system
- Serve as an energy source
What is amino acids?
Amino acids are “building blocks” of proteins
How many different naturally occurring amino acids are there?
20
What are proteins made up of?
Amino acids
How are amino acids joined together?
Amino acids are joined together via peptide bonds
Do you remember the structure of an amino acid?
If yes, good but if no, go and see your notes
Can amino acids be used for energy or to make glucose?
Yes
What is the most important function of amino acids?
The most important function of amino acids is to build proteins
What happens when the diet contains more protein than you need?
The excess can be used for energy production, converted to glucose or stored as fat
What are the more efficient energy sources?
Carbohydrate and Fat
Can amino acids be broken down to produce energy?
Yes
What are the characteristics of amino acids? (3 characteristics)
- Amino acids are “Ampholytes”
- They are “Zwitterions
- Due to their ionic nature, they have extremely high melting temperatures
What are “Ampholytes”?
They can act as either an acid or a base
What are “Zwitterions”?
They are molecules that have both a positive and a negative charge
What are peptides composed of and how are they linked?
Peptides are composed of more than 1 amino acid linked by peptide bonds
Do you remember how to draw a peptide bond?
If yes, good but if no, go and see your notes
For example, if two amino acids are mixed together (Glycine + Alanine), what are the results?
The results will be Glycine + Alanine => Water + Dipeptide
A peptide bond connects two amino acids, forming a dipeptide, and is associated with the loss of a water molecule
What does the structure of proteins determine?
It determines the structure and function
What are the 4 types of protein structures?
- Primary
- Secondary
- Tertiary
- Quaternary
What is a primary structure?
Primary structure = order of amino acids in the protein chain
It is the linear sequence of amino acids joined together by a peptide bond
What is a secondary structure?
Secondary structure = local folding of residues into regular patterns
What are the types of secondary structure? (3 types)
- Alpha helix
- Beta sheets
- Beta-turns
What is an alpha helix?
- Helical arrangement of amino acids in the polypeptide chain
- Maintained by hydrogen bonds parallel to the helix axis
What are beta sheets?
- Hydrogen bonds form between adjacent sections of polypeptides
- Either running in the same direction (parallel) or in the opposite direction (anti-parallel)
What do the alpha helix and beta sheets have in common?
They are both stabilized by hydrogen bonds
What is beta-turns?
- It reverses the direction of the polypeptide chain
- Connecting the ends of anti-parallel B pleated sheets
What is a tertiary structure?
Tertiary structure = global folding of a protein chain
It is a three-dimensional arrangement of the amino acids in the polypeptide chain and is biologically active
What is a quaternary structure?
Quaternary structure = higher-order assembly of proteins
Protein composed of more than one polypeptide chain in a spatial arrangement
What is an example of a quaternary structure?
Hemoglobin
How many polypeptide chains does hemoglobin consist of?
Consists of 4 polypeptide chains
- 2 alpha chains (141 amino acids)
- 2 beta chains (146 amino acids)
What are the classes of proteins? (3 classes)
- Functional definition
- Structural definition
- Cellular localized definition
What is in functional definition? (4 types)
- Enzymes
- Structural
- Transport
- Defense
What is in structural definition? (2 types)
- Globular
- Fibrous
What is in cellular localized definition? (2 types)
- Membrane
- Soluble
What is the definition of “Enzymes” in functional definition?
Accelerate biochemical reactions
What is the definition of “Structural” in functional definition?
Form biological structures
What is the definition of “Transport” in functional definition?
Carry biochemically important substances
What is the definition of “Defense” in functional definition?
Protect the body from foreign invaders
What is the definition of “Globular” in structural definition?
Complex folds, irregularly shaped tertiary structures
What is the definition of “Fibrous” in structural definition?
Extended, simple folds, generally structural proteins
What is the definition of “Membrane” in cellular localized definition?
In direct physical contact with a membrane; generally water insoluble
What is the definition of “Soluble” in cellular localized definition?
Water soluble; can be anywhere in the cell
What are enzymes?
Enzymes are biological catalysts
What do enzymes convert?
Enzymes convert substrates into products
What is required to initiate a chemical reaction?
Activation energy is required
For the reaction to proceed at a much faster rate, what do enzymes do?
Enzymes lower the activation energy, so a reaction proceeds at a much faster rate
Complete the following, Enzyme + Substrate => _________ => _________ + _________
Enzyme + Substrate => Enzyme Substrate Complex => Enzyme + Product
What is active site?
Active site is a crevice (space) on the surface of the protein
What is the function of the active site?
It binds the substrate to form an enzyme-substrate complex, and transforms it into a product
Why do active site and substrate have complementary shapes?
Because it enables them to bind together with a high degree of specificity
Is active site highly specific and why?
Yes, because it allows only the proper substrate to fit into the active site
What are the two models for enzyme binding?
- Lock and key model (fixed) = like puzzle pieces
- Induced fit model (not fixed) = like playdoh
What are the factors affecting enzyme structure and activity? (4 factors)
- Heat (temperature)
- pH changes
- Enzyme concentration
- Substrate concentration
Why does heat (temperature) affect enzyme structure and activity?
Heat (temperature) disrupts hydrogen bonding, causing the enzyme to change its shape and lose activity
Why does pH changes affect enzyme structure and activi
pH changes alter the charge of the amino acids, thus affecting the structure and ability to bind a substrate
What are the two types of nucleic acids?
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
What is deoxyribonucleic acid (DNA)?
DNA is the genetic “blue-print” and carries all the instructions needed to build a new material
How is deoxyribonucleic acid (DNA) arranged and where is it located?
DNA is arranged into chromosomes and is located in the nucleus
Where are the genes of DNA located and what does one gene do?
Genes are located on the chromosome
One gene codes for information to make one protein
What is are three subclasses of ribonucleic acid (RNA)?
- mRNA (messenger)
- tRNA (transfer)
- rRNA (ribosomal)
What is DNA made up of?
DNA molecule consists of a ladder, formed by sugars and phosphates and four nucleotide bases
(Made up of nucleotides => sugar + base + phosphates)
What are the four nucleotide bases?
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
How are the bases of one helical strand in DNA paired with?
They are paired with complementary bases of the other
What does Adenine (A) pair with?
What does Guanine (G) pair with?
- The bases Adenine (A) pairs together with Thymine (T)
- The bases Guanine (G) pairs together with Cytosine (C)
How many hydrogen bonds is Adenine-Thymine base pair held with?
2 hydrogen bonds
How many hydrogen bonds is Guanine-Cytosine base pair held with?
3 hydrogen bonds
If there are more hydrogen bonds, does it require more heat to break up?
Yes
What are the characteristics of DNA? (4 characteristics)
- Double stranded
- Nucleotides
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T) - Sugar = Deoxyribose
- Chromosomal nucleic acids
What are the characteristics of RNA? (4 characteristics)
- Single stranded
- Nucleotides
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Uracil (U) - Sugar = Ribose
- Intermediate which translates gene information to produce proteins