B1.1 Carbohydrates & Lipids Flashcards
Outline the number and type of bonds carbon can form with other atoms
carbon can form 4 single covalent bonds with other atoms
- The covalent bond is considered to be a stable bond and therefore, its presence gives stability to molecules
- the fact that carbon can bind to four different atoms allows for formation of an array of diverse molecules in which carbon plays an important part
Outline the cause and consequence of covalent bonds between atoms
- Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell
- It often happens that covalent bond formation does not lead to an equal sharing of a pair of electrons between two atoms
what are the common functional groups?
common functional groups:
- hydroxyl
- carbonyl
- carboxyl
- amine
- phosphate
what common functional group is this?
hydroxyl
what common functional group is this?
carbonyl
what common functional group is this?
carboxyl
what common functional group is this?
amine
what common functional group is this?
phosphate
List the four major classes of carbon compounds used by living organisms
- carbohydrates
- lipids
- proteins
- nucleic acids
List example molecules with branched chains
- Amylopectin
- Glycogen
Examples of molecules with unbranched chains
- Amylose
- Cellulose
Examples of molecules with a single ring
- Alpha glucose
- Beta glucose
- Ribose
- Deoxyribose
Examples of molecules with multiple rings
- Maltose
- Sucrose
- Lactose
Define monomer and polymer
- Monomer = a simple unit that makes up larger molecules + which can be bonded with similar molecules to form a polymer
- Polymer = a substance with a chemical structure formed of many repeating units of monomers
what are triglycerides?
- they are non-polar macromolecules and one of the most common types of lipid
- they are formed from one molecule of glycerol and 3 fatty acid molecules
what are fatty acids?
fatty acids are carboxyl groups (COOH) with a hydrocarbon tail
there are hundreds of fatty acids
- the hydrocarbon tail can be saturated (C-C single bonds) OR unsaturated (at least one C=C double bond)
- the tail can also vary in length
describe condensation reactions
a condensation reaction removes a water molecule to join two monomers via a covalent bond
- it is used to make polymers
DIFFERENT TYPES OF BONDS THAT CAN BE MADE:
- peptide bonds (in proteins) formed btwn two amino acids
- Glycosidic Bonds (in carbohydrates)
formed between two monosaccharides - Ester Bonds (in lipids) formed between glycerol and fatty acids
- Phosphodiester Bonds (in nucleic acids) formed between two nucleotides (btwn phosphate group and sugar)
what is needed to produce macromolecules by condensation reactions?
you need energy from ATP in order to produce macromolecules by condensation reactions
Outline the condensation reactions that form
- polysaccharides
- polypeptides
- nucleic acids
- Monosaccharide units are joined by a carbon-oxygen linkage known as a glycosidic bond to form a chain called a polysaccharide
- When amino acids bond, water is lost and the nitrogen and carbon bond to form a peptide bond, and creates a polypeptide
what are monosaccharides?
- Monosaccharides are the monomers that make up carbohydrates
- it is a single sugar molecule
- it has a backbone of 3-7 carbon atoms
- it has a ring structure
- it is hydrophilic and soluble in water
- examples: glucose, galactose, fructose
Describe hydrolysis reactions
- it is a chemical reaction in which a polymer breaks apart into monomers
- the addition of water is used to break the bonds
- the reaction releases energy
a single macromolecule is called __?
a long chain of monomers is __?
- a single macromolecule is referred to as a monomer
- a long chain of monomers is a polymer
Outline the hydrolysis reactions that digest
- polysaccharides
- polypeptides
- nucleic acids
- A polysaccharide releases energy when digested via a hydrolysis reaction, broken down into monosaccharides
- The hydrolysis reaction of polypeptides breaks them down into monomers that are amino acids
- Nucleic acids are broken down by enzymes called nucleases into nucleotides
identify pentose and hexose carbohydrates from molecular diagrams
know how to do this!
- pentose = five member ring
- hexose = six member ring
which one is pentose and which one is hexose?
left = hexose
right = pentose
Outline the properties of glucose referring to
- solubility
- transportability
- stability
- energy yield from oxidation
They are:
- Soluble in water
- Easily transported through cell membranes
- Needed to make ATP during cellular respiration
define polysaccharide
- they are polymers of monosaccharides linked by glycosidic bonds to form a chain
(it is the proper term for a starch)
Compare the structure and function of amylose, amylopectin, and glycogen
AMYLOSE:
- Amylose is an unbranched structure (it has a spiral structure instead)
- has 1,4 glycosidic bonds
- A polymer of alpha-glucose
- Amylose is harder to digest and less soluble, BUT, as it takes up less space, is the preferred storage form in plants (this is its function)
AMPLYOPECTIN:
- Amylopectin is a branched structure
- 1,4 and some 1,6 glycosidic bonds
- A polymer of alpha-glucose
- function = to store energy in plants and make up the structure of the plant starch granule as a storage unit
GLYCOGEN:
- A polymer of alpha-glucose
- it is branched more frequently, has a branched structure
- it is an energy store of glucose
- it does not affect the water potential of the cells
what is the benefit of polysaccharide coiling and branching during polymerization?
- Becoming tightly compacted through coiling helps keep energy stored for a later time.
- In cellulose, it also provides strength in its structure
Explain how condensation or hydrolysis of alpha-glucose monomers build or mobilize energy stores
- Amylose, Amylopectin, Glycogen, and Cellulose (polymers of alpha-glucose) are formed by condensation reactions
- Polysaccharides release energy via a hydrolysis reaction
SO, the condensation or hydrolysis of alpha-glucose monomers can build/mobilize energy stores
compare the structure of alpha-glucose and beta-glucose
- Alpha glucose has the H above and the OH below the carbon 1, the bond is pointing down
- Beta glucose has the OH above and the H below the carbon 1, the bond is pointing up
Describe the structure of cellulose microfibrils
- Cellulose microfibrils consist of bundles of around 36 cellulose chains
- These chains are embedded in a matrix of hemicellulose and lignin, which provides additional structural support
- The individual cellulose chains run parallel to each other. Hydrogen bonds form between these chains, holding them together to create strong microfibrils
- The microfibrils are highly strong due to the collective hydrogen bonding between chains
The hydrogen bonds between cellulose chains are weaker than the glycosidic bonds that link the glucose monomers within each chain
what is cellulose?
- Main structural sugar in plants
- Fibrous, and therefore an important structural component of plant cell walls
- Very strong
- Permeable to numerous substances
- About 33% of plant matter
- Most common organic compound on Earth
what are the consequences of the strength of cellulose in the plant cell wall?
the strength of cellulose in the plant cell wall help maintain the rigidity strength and shape of cell walls
what is the function of glycoproteins in the cell membrane?
- Glycoproteins play a role in cell-cell recognition as they act as markers on the surface of cells. (ex. immune cells recognise and attack foreign cells that display different glycoproteins)
- Glycoproteins can act as receptors on the surface of cells
- Other glycoproteins can act as ligands
- Glycoproteins also contribute to the structural integrity of cells and tissues
what are glycoproteins?
Glycoproteins = proteins that have one or more carbohydrates attached to them. These carbohydrates can be attached to specific amino acid residues within the protein.
compare the structure of the A, B, and O glycoproteins on the red blood cell membrane
A, B, and O glycoproteins all have similar basic structures (same core structure of oligosaccharides on red blood cell membranes)
Type A glycoproteins:
- Have an extra glycosidic bond to N-acetyl-galactosamine (GalNAc).
Type B glycoproteins:
- Have an extra glycosidic bond to galactose (Gal)
Type O glycoproteins:
- Lack the extra monosaccharides (either GalNAc or Gal) found in A and B glycoproteins.
- Type O individuals have a glycoprotein with one less sugar in the oligosaccharide chain compared to A and B.
the ABO blood group system is based on the presence of specific glycoproteins on the surface of red blood cells
what are the consequences of the presence of A, B, and O glycoproteins during blood transfusion?
- If blood containing glycoprotein A is transfused into a person who does not produce it themself, the blood will be rejected
- Similarly, blood containing glycoprotein B is rejected if a person does not produce it themself
- However, glycoprotein O does not cause rejection problems, because it has the same structure as A and B with one monosaccharide less, so it will not be recognized as foreign
BAISICALLY:
- The compatibility of blood types is based on recognition and interaction of specific glycoproteins on the surface of red blood cells
When incompatible blood types are mixed, the immune system can recognise the other glycoproteins as foreign molecules and attack
The ABO blood group system is based on ____?
it is based on the presence of specific glycoproteins on the surface of red blood cells
why are lipids hydrophobic?
- Lipids are hydrophobic because they do not contain a lot of -OH bonds. Instead, they contain a lot of -CH bonds
- This causes them to be nonpolar, and not very readily available to form hydrogen bonds with water
Outline the structure and function of
- fats and oils
- there are 3 fatty acids + glycerol
- they are used for long-term energy storage
Outline the structure and function of
- waxes
- they are composed of long hydrocarbon chains
- waxes have a protective and coating function in live organisms as they are insoluble in water and form a waterproof protective coating
Outline the structure and function of
- steroids
- they have a backbone of four carbon rings
- steroids reduce the fluidity of the cell membrane
Explain the condensation reaction connecting fatty acids and glycerol to form a triglyceride
The hydroxyl groups of glycerol combine with the carboxyl groups of the fatty acids to form an ester linkage
Explain the condensation reaction connecting fatty acids, glycerol and a phosphate group to form a phospholipid
- The hydroxyl groups of glycerol combine with the carboxyl groups of the fatty acids to form an ester linkage
- The third oxygen on glycerol is bonded to a phosphoric acid through a phosphate ester bond
how are phospholipids formed?
by connecting fatty acids, glycerol and a phosphate group via a condensation reaction
how are triglycerides formed?
by connecting fatty acids and glycerol via a condensation reaction
Describe + draw the structure of a generalized fatty acid
- it is a long chain of mostly carbon and hydrogen atoms with a COOH carboxyl group at the end
Compare and contrast the structures and properties of saturated and unsaturated fatty acids
- Saturated fatty acids have single bonds satisfied and are solid at room temperature
- Unsaturated fatty acids have double bonds and not all bonds satisfied, typically liquid at room temperature
Distinguish between the structure and properties of cis- and trans-unsaturated fatty acids
- Cis has hydrogen atoms on the same side of the C double bond and causes a kink in the chain, naturally occurring.
- Trans has hydrogen atoms on opposite sides of the C double bond, causing a straighter chain, not found in nature
Unsaturated fatty acids can be further subclassified into ___ or ____?
Unsaturated fatty acids can be further subclassified into either Cis or Trans fatty acids,
unsaturated fatty acids can be ___-unsaturated or ___-unsaturated
what are triglycerides suitable for?
they are suitable for long-term energy storage
what properties of triglycerides make them suitable for long-term energy storage?
Triglycerides are excellent long-term energy storage molecules because they will not mix with water and break down
what is the function of adipose tissue?
The main function of adipose tissue is to store energy in the form of lipids
what is the adaptation of a thick adipose tissue layer?
- the adaption of a thick adipose tissue layer works as a thermal insulator
- the layer does not transfer heat as well as other tissues and materials (such as muscle or skin), so it is good at insulating and trapping heat
draw a simplified diagram of the structure of the phospholipid (including a phosphate-glycerol head and two fatty acid tails)
Define
- hydrophilic
- hydrophobic
- amphipathic
- Hydrophilic = “water loving,”
- Hydrophobic = “water fearing,”
- Amphipathic = having both hydrophilic and hydrophobic properties
Outline the amphipathic properties of a phospholipid
A phospholipid has a hydrophilic head and a hydrophobic tail
Explain why phospholipids form bilayers in water
(with reference to hydrophilic phosphate heads and two hydrophobic hydrocarbon tails)
They form bilayers because of their amphiphilic characteristics
- The hydrophilic phosphate heads can bond with water and position themselves on the outside
- the hydrophobic hydrocarbon tails do not bond with water so they face away from the water
When exposed to water, phospholipids form one of two structures:
____ or _____
a micelle or a bilayer
- In each structure, the hydrophilic heads face the water, and the hydrophobic tails point inwards away from the water
why are phospholipid bilayers ideally suited in membranes?
Cells usually exist in aqueous environment. The inside of cells are also aqueous.
Phospholipid bilayers are therefore ideally suited in membranes as it allows the outer surfaces of the hydrophilic heads to interact with water
understand how to label these diagrams
what is this showing?
it is a molecular diagram showing steroid molecules
why are steroid hormones able to pass directly through the phospholipid bilayer?
Because they are hydrophobic molecules,
they are capable of passing through the phospholipid bilayer of cells to reach their target receptor site usually inside the nucleus
- they can also pass through the nuclear envelope (this allows these cells to have a faster response to the presence of these steroids allowing the signal to occur more efficiently)
____ is able to pass directly through the phospholipid bilayer
steroid hormones are able to pass directly through the phospholipid bilayer
what are steroids?
- Steroids = a group of naturally occurring hormones that play a vital role in regulating a wide range of physiological functions in the body
- steroids = hydrophobic molecules
describe the composition of steroids
they are composed of four carbon-based rings as the basic structure
BUT the difference in functional groups is vast, allowing steroids to have a diverse array of functions
Give two examples of monomers
monosaccharides, amino acids
Explain what happens in a condensation reaction between two monomers
Two monomers are joined together with the release of water.
What type of reaction involves the breakage of a chemical bond between two monomers using water?
Hydrolysis
what is maltose?
Maltose = a disaccharide formed from two alpha-glucose molecules, joined by a glycosidic bond
Draw a flow diagram to show the breakage of maltose into two a-glucose monomers. (picture of maltose included)
(add water)
what is sucrose?
Sucrose = a disaccharide formed from an alpha-glucose and a fructose molecule, joined by a glycosidic bond
How do we test for starch?
use iodine. it turns yellow/brown to purple/black
Why is it important that there are free sugars at the end of glycogen chains?
They are easily hydrolysed to provide energy and glucose can easily be added for storage
What force holds chains of cellulose together?
Hydrogen bonds
Why is fibre (cellulose) important for our diet?
improves digestion, reduces constipation, makes us feel fuller, reduced risk of type 2 diabetes, etc
Describe how a triglyceride is broken down into its component parts
Triglycerides are broken down by the process of hydrolysis. Water is added to break the 3 ester bonds. This produces one molecule of glycerol and 3 fatty acids.
Carbon atoms can form up to __?
four single bonds or a combination of single and double bonds with other carbon atoms or atoms of other non-metallic elements
Macromolecules are produced by?
condensation reactions that link monomers to form a polymer
- Polymers can be digested into monomers by hydrolysis reactions that split water molecules to provide the -H and -OH groups necessary to produce monomers
Glucose is?
a stable polar monosaccharide (hexose) that is soluble in blood plasma and can be oxidised in cellular respiration
Polysaccharides are?
energy storage compounds that are compact and insoluble due to their large molecular size and coiling and branching during polymerisation
(examples = starch and glycogen)
Cellulose is?
a structural polysaccharide in plants with straight chains that can be grouped in bundles and cross-linked with hydrogen bonds
Glycoproteins play a role in?
cell-cell recognition, such as ABO antigens
Lipids are?
are substances in living organisms that dissolve in non-polar solvents and include fats, oils, waxes and steroids
Triglycerides in adipose tissues are?
used for long-term energy storage and thermal insulation
Phospholipid bilayers are formed as a consequence of?
the hydrophobic and hydrophilic regions of phospholipids, which allow hydrophobic steroids to pass through them, such as oestradiol and testosterone
