Macromolecules

Question 1

Molecule

Answer 1

This is made up of elements.

Question 2

Element

Answer 2

A substance that cannot be broken down or converted into another substance by chemical means. These are made up of 1 type of atom.

Question 3

Atom

Answer 3

The smallest particle of an element that still retains the elements distinctive chemical properties.

Question 4

Neutrons

Answer 4

A non-charged or neutral subatomic particle found in the nucleus of an atom.

Question 5

Protons

Answer 5

Positively charged subatomic particles found in the nucleus of an atom. The number of protons is what determines the atomic number and therefore the element.

Question 6

Electrons

Answer 6

Negatively charged subatomic particles found in shells that orbit the nucleus of an atom.

Question 7

Electron Shells

Answer 7

These orbit the nucleus of an atom and are arranged in different energy levels. These energy levels have a maximum number of electrons they can contain. Most elements have an incomplete outer energy level which can undergo chemical reactions in order to fill up or empty the outer energy level by donating or accepting electrons in order to achieve stability.

Question 8

Covalent Bonds

Answer 8

A type of chemical bond in which the electrons are shared between both molecules which results in a neutral or non-charged product as the number of electrons and protons (charges) are the same. There are a few types of these with 2 examples being singular and others being double.

Question 9

Single Covalent Bonds

Answer 9

This is when there is an equal sharing of 2 electrons by both atoms. This allows for rotation which can change the orientation to other molecules attached to the bonded molecules.

Question 10

Double Covalent Bonds

Answer 10

This is when 4 electrons are equally shared by both atoms. The presence of 2 bonds means the structure is rigid and doesn’t allow for any rotation.

Question 11

Macromolecules

Answer 11

Aside from water these are the most abundant compounds inside cells e.g. DNA, RNA, proteins etc. These are constructed by linking smaller molecules together via covalent bonds. Carbon is a part of nearly all of these which can form into small organic molecules or into highly stable chains and rings. Carbon molecules are the building blocks for these and are used for structural support, work, information and energy storage etc.

Question 12

Carbohydrates

Answer 12

A macromolecule formed by simple sugars. These are a hydrate of carbon (water + carbon) (CH2O)*n where n is typically 3,4,5 or 6.

Question 13

Monosaccharide

Answer 13

A singular sugar molecule e.g. glucose.

Question 14

Disaccharide

Answer 14

A sugar molecule composed of 2 monosaccharides e.g. sucrose from glucose and fructose.

Question 15

Oligosaccharide

Answer 15

A sugar molecule composed of 3-50 monosaccharides.

Question 16

Polysaccharide

Answer 16

A sugar molecule composed of 100s - 1000s of monosaccharides. These can be branched or linear in structure.

Question 17

Aldose Sugar

Answer 17

When these cyclise the hydroxyl group on the second to last carbon undergoes an intramolecular reaction with the aldehyde carbonyl group.

Question 18

Ketose Sugar

Answer 18

When these cyclise the hydroxyl group on the second to last carbon undergoes an intramolecular reaction with the ketone carbonyl group.

Question 19

Condensation Reaction

Answer 19

These reactions lead to water being released as a product. This is the reaction that occurs when a covalent bond between the subunits of macromolecules is formed. This reaction leads to 2 subunits with one containing a hydroxyl group and the other without one and water as the other product.

Question 20

Hydrolysis Reaction

Answer 20

These reactions require the addition of water as a reactant. These occur when a covalent bond between subunits of a macromolecule is broken. This reaction requires water and 2 subunits with the result being a combination of the subunits which will contain 2 hydroxyl groups which are gained from the water and 1 hydrogen already present on the subunit.

Question 21

Alpha Glucose

Answer 21

This makes up 36% of the glucose in the body. This variation exists when the hydroxyl group on carbon 1 of the ring is positioned below the ring.

Question 22

Beta Glucose

Answer 22

This makes up 64% of the glucose in the body. This variation exists when the hydroxyl group on carbon 1 of the ring is position above the ring.

Question 23

Structural Role of Carbohydrates

Answer 23

The linking of 1-4 (the hydroxyl group attached to carbon 1 loses the hydrogen and bonds to carbon 4 on the next glucose ring) beta glucose forms the molecule cellulose. This is the most abundant organic molecule on Earth. It makes up the walls of plant cells and provides structure and can be made up of 100s - 10000s of units of glucose.

Question 24

Energy Source Role of Carbohydrates

Answer 24

This is gained from glycogen in animal cells which has alpha 1-4 (linear) and alpha 1-6 (branched) bonds. In plant cells starch is used for this purpose which has the same bonding types. The difference between glycogen and starch however is that glycogen has more branches and starch is made up of more than 1 polysaccharide.

Question 25

Lipids

Answer 25

These are amphipathic meaning they have both a hydrophilic (water loving) and hydrophobic (water hating) part. This means that the base units fatty acids are insoluble in water but are soluble in fat and organic solvents.

Question 26

Unsaturated Fatty Acid

Answer 26

These contain double bonds linking carbon atoms in the hydrophobic tail. The double bond repels the molecules around it meaning kinks in the chain which don’t allow for the close packing of molecules. These fats are liquid at room temperature e.g. plant oils (canola, corn, olive).

Question 27

Saturated Fatty Acid

Answer 27

These don’t contain double bonds in the hydrophobic tail. This means there is no repulsion forces meaning that molecules can be tightly packed together. These are typically solid at room temperature e.g. animal fats (butter, lard).

Question 28

Fatty Acid

Answer 28

These are the subunits of fat and is mostly used as energy reserves in cells and can store 6x as much energy as glucose per weight. This general fat is solid whereas oil is liquid at room temperature (25C). These are typically stored as triglyceride molecules which contains 3 fatty acids attached to 1 glycerol. This is through an ester linkage between the glycerol and the carboxylic head on the fatty acid.

Question 29

Phospholipids

Answer 29

These molecules are made up of 2 fatty acids linked to glycerol meaning there are 2 hydrocarbon tails. The 3rd site on the glycerol is linked to a phosphate group which also has a small hydrophilic group attached covalently to the phosphate group. These molecules are highly amphipathic. These molecules are the main component of cell membranes which makes a bilayer with the hydrophilic sections of both layers facing outward and the hydrophobic sections facing each other inwards.

Question 30

Glycolipids

Answer 30

These are similar to phospholipids but the sugar groups replace the phosphate and the hydrophilic part of the molecule. These are amphipathic. They are mainly on the cytosolic surface of the plasma membrane which is useful for cell-to-cell recognition for intercellular connections.

Question 31

Steroids

Answer 31

These are hormones such as testosterone and estradiol. These are signaling molecules and can pass through cell membranes.

Question 32

Nucleic Acid

Answer 32

DNA is transcribed into RNA which is then translated into proteins. DNA is deoxyribonucleic acid which is used a long-term storage of hereditary material. RNA is ribonucleic acid which is used as a transient carrier of information. Both of these molecules consist of nucleotides.

Question 33

Nucleotides

Answer 33

These organic molecules typically contain nitrogen, carbon and hydrogen with some also containing oxygen. This structure typically has a phosphate backbone, a pentose sugar group and a nitrogenous base. These are classified into 2 types which are pyrimidines (single ring structures e.g. cytosine (C), thymine (T) and uracil (U)). The second type are purines (double ring structures e.g. adenine (A) and guanine (G)).

Question 34

Nucleoside

Answer 34

The structural unit considered when ignoring the phosphate backbone on a nucleotide. This means it consists only of the pentose sugar (deoxyribose or ribose) and the nitrogenous base (A, T, U, C or G).

Question 35

Phosphoanhydride Bond

Answer 35

These bonds connect phosphate groups together in a condensation reaction.

Question 36

Nucleotide Structure

Answer 36

In DNA and RNA the phosphates are normally joined the the C5 hydroxyl group of the pentose sugar. This means that mono, di and triphosphate molecules are common. The difference in sugars also means that there are different nucleotides for DNA and RNA. DNA has dATP, dTTP, dCTP and dGTP while RNA has ATP, UTP, CTP and GTP.

Question 37

Nucleic Acid Sequence & Direction

Answer 37

The hydroxyl group on the 3rd carbon of the pentose sugar is covalently linked to the phosphate group attached to the 5th carbon of the adjacent pentose (this creates the sugar phosphate backbone for DNA and RNA). These polymers (strands) have directionality a 5’ end and a 3’ end. By convention the sequences of bases (genetic information) in a nucleic acid strand is read from 5’ - 3’ using the single letter code e.g. 5’-G-A-C-T-T-3’. The DNA molecules are double stranded whereas the RNA molecules are single stranded.

Question 38

Chemical Energy

Answer 38

A function of nucleotides in which phosphoanhydride bonds are hydrolysed. When this occurs the energy conserved in that bond is released and can be used by cells e.g. ATP energy.

Question 39

Signaling Molecule

Answer 39

A function of nucleotides in which starved bacterial cells begin to produce cyclic AMP (cAMP) which is a ring shaped molecule formed by the phosphate group with multiple carbons on the same sugar. The cAMP activates enzymes and turns on genes to find or create more ATP.

Question 40

Coenzyme

Answer 40

A function of nucleotides in which nucleotides combine with other groups. When they are activated they transfer groups between these molecules and the combinations will act as enzymes.

Question 41

Proteins

Answer 41

These molecules are made up of amino acids. These form into linear polymers with directionality. They begin with an amine group known as the N terminus and ends with a carboxylic acid group known as the C terminus.

Question 42

Amino Acids

Answer 42

These are the subunits of proteins which have an alpha (central) carbon, a carboxylic acid group, an amino group and a side chain. The side chain differences is what distinguishes the properties of different amino acids. These can be charged or neutral depending on whether there is an extra hydrogen on the amine group (positive charge) or if a hydrogen is removed from the carboxylic acid group (negative charge). The same group of of these are found in the proteins of bacteria, animals and plants. These will use peptide bonds to combine and form proteins.

Question 43

Peptide Bonds

Answer 43

These bonds link amino acids together to form proteins. The carboxylic acid group of 1 amino acid reacts with the amine group of another amino acid. This reaction is a condensation reaction (produces water) whereas breaking the bond is a hydrolysis reaction (requires water). Despite requiring the amine and carboxylic acid groups to form bonds chains of amino acids each individual amino acid still has both groups.

Question 44

Macromolecules

Answer 44

These are made up of smaller subunits such as simple sugars, amino acids and nucleotides. These are formed with covalent bonds through condensation reactions. These formed particles can then undergo non-covalent interaction to bond with one another to form larger assemblies e.g. proteins forming into an enzyme.

Question 45

Ionic Interactions

Answer 45

When atoms lose or gain electrons which results in electrically charged particles (ions). These come in 2 forms which are cations which are positively charged from the loss of electrons (Na+). The other form in anions which are negatively charged from gaining electrons (Cl-).

Question 46

Attraction

Answer 46

Opposite charges attract each other and hold together through ionic bonds. In the presence of water these bonds aren’t as strong as the water molecules shield the charges of the 2 particles. In the absence of water these bonds are much stronger as the charges aren’t shielded from one another.

Question 47

Polar Covalent Bonds

Answer 47

The unequal sharing of electrons belonging to a bond between 2 atoms. This is caused if one atom in a bond has a higher electronegativity than other atoms e.g. oxygen in water attracts electrons more strongly that hydrogen.

Question 48

Electronegativity

Answer 48

An atoms affinity to gaining electrons.

Question 49

Hydrogen Bonds

Answer 49

Bonds which form if the polarised molecule contains a hydrogen atom and is between 2 electron attracting atoms e.g. oxygen in water. This can also be nitrogen in other molecules. These bonds are based on electrostatic interactions and not from electron sharing like covalent bonds. They are weak compared to covalent bonds 1/20th the strength and are strongest when the 3 atoms in it are arranged in a straight line. Despite 1 of these bonds being weak the sum of the bonds allows for a stronger structure but also allows for flexibility and reactivity.

Question 50

Dipole

Answer 50

A polarised molecule. This means there is positively charged and negatively charged parts of the molecule. This is created by polar covalent bonds meaning it can attract other polarised molecules.

Question 51

Water

Answer 51

This molecule has hydrogen bonds. During extremely cold extended period only the top layer freezes as it forms a liquid crystalised structure which forms tight interactions with some space between. This allows for it to remain fluid beneath and for interaction between different molecules to occur. This means that its solid form is less dense than its liquid form which is why the solid portion floats above the liquid.

Question 52

Hydrophobic Forces

Answer 52

Also known as water-hating. These molecules cluster together to exclude water molecules. This detraction to water causes these molecules to squeeze together to form a larger molecule. This creates a new type of bond caused not by the attraction to the same molecules but their shared detraction to water molecules.

Question 53

Van Der Waals Attractions

Answer 53

These forces include attraction and repulsions between atoms, molecules and surfaces as well as other intermolecular forces. These result from a transient shift in electron density around a nucleus that creates a transient charge to which a nearby atom is attracted to or repelled by. These are the weakest interaction type and are only effective when atoms have a specific distance from one another.

Question 54

Non-Covalent Interactions

Answer 54

These are intermolecular forces which are weaker than the intramolecular forces which involve electron sharing. Although singularly these forces aren’t as strong there are typically many of these interaction together which help to form stronger interactions. This is what helps to maintain the structures of macromolecules such as proteins and DNA but also allows for the flexibility in order to be altered or changed when necessary e.g. DNA split for transcription. There are 4 major types of ionic interactions, hydrogen bonds, hydrophobic forces and Van der Waals attractions.