Biology Paper 1 - Biological Molecules (3.1)

What is a monomer?

One of many small repeating molecules that combine to form a polymer.

What is a polymer?

Large molecule made up of many repeating smaller molecules.

What is polymerisation?

Process of producing a polymer.

What is a condensation reaction?

Joins 2 molecules together with the formation of a chemical bond and involves the elimination of a molecule of water.

What is a hydrolysis reaction?

Breaks a chemical bond between two molecules and involves the use of a water molecule.

What is metabolism?

All chemical reactions processes that take place within the cells of an organism.

What is the monomer of a carbohydrate?

Monosaccharides

What are some examples of monosaccharides?

glucose (alpha, beta), fructose, galactose

What does the condensation reaction between two monosaccharides form?

glycosidic bond

What are some examples of disaccharides.

Maltose, Sucrose, Lactose

What elements do carbohydrates contain?

Carbon
Hydrogen
Oxygen

How are disaccharides formed?

from a condensation reaction between 2 monosaccharides

How is maltose formed?

formed by a condensation reaction of 2 alpha-glucose molecules.

How is sucrose formed?

formed by a condensation reaction of 1 alpha-glucose molecule and a fructose molecule.

How is lactose formed?

formed by a condensation reaction of 1 alpha-glucose molecule and a galactose molecule.

What is an isomer in carbohydrates?

same chemical formula, different structure.

What are the 2 types of glucose?

alpha glucose and beta glucose.

How are polysaccharides formed?

by the condensation of many glucose units.

What are some properties of monosaccharides?

: dissolves in water
: reducing sugars

What are some properties of disaccharides?

: Dissolves in water
: Can be reducing or non reducing sugars
: Forms a covalent bond called a glycosidic bond

How does the structure of alpha and beta glucose change the bonding?

every other beta-glucose molecule is upside down.

Name some examples of polysaccharides?

Starch, glycogen, cellulose

What is the structure of starch?

: Polysaccharide of alpha-glucose
: 1-4 and 1-6 glycosidic bonds
: Branched and coiled shape held by hydrogen bonds within the molecule

What is the structure of glycogen?

: Polysaccharide of alpha-glucose
: 1-4 and 1-6 glycosidic bonds
: Branched and coiled shape held by hydrogen bonds within the molecule

Where is starch only made?

Plants

Where is glycogen only made?

Animals

What does glycogen and starch being insoluble do?

does not affect the water potential, meaning the concentration of water stays the same

What does glycogen and starch being branched/helical do?

: Compact/can fit many in a small space.
: Many ends of enzymes to attach and hydrolyse to release glucose.

What does glycogen and starch being a polymer of alpha-glucose do?

provides glucose for respiration

What does glycogen and starch being large do?

cannot leave the cell.

which is more compact? glycogen or starch?

starch

Which has more 1-6 glycosidic bonds? glycogen or starch?

glycogen

What are some features of the cellulose structure?

: Polysaccharide of beta-glucose
: Every other beta-glucose is upside down
: 1-4 glycosidic bonds ONLY
: each molecule forms a long and straight chain
: Many hydrogen bonds between chains forming microfibrils

What elements do triglycerides contain?

Carbon
Hydrogen
Oxygen

What are features of triglycerides?

: Insoluble in water/non polar

What are the 2 main groups of lipids?

: Triglycerides - also knows as fats (solids at room temperature) and oils (liquid at room temperature)
: Phospholipids - main component of plasma membrane

What are triglycerides made up of?

glycerol and 3 fatty acids

what are the glycerol and fatty acids in triglycerides joined together by?

ester bonds

what does the condensation reaction of triglycerides release?

3 water molecules

what are saturated bonds?

single c-c bonds in the hydrocarbon chain

what are unsaturated bonds?

double c=c bonds in the hydrocarbon chain

do fatty acids have hydrocarbon chains?

yes

what are some properties of triglycerides?

: energy store
: large, insoluble and non polar molecules
: storage below dermis of the skin in adipose tissue
: metabolic source of water
: buoyancy

why do triglycerides have energy store?

many more carbon and hydrogen so more energy per g then carbohydrates

why do triglycerides have a large, insoluble and non polar structure?

so it doesn’t affect the water potential of the cell

why do triglycerides have a storage below the dermis of the skin in adipose tissue?

acts as an insulator for extreme temperatures.

why do triglycerides have a metabolic source of water?

due to their oxidation during respiration producing a high volume of water

why do triglycerides have a high buoyancy?

less dense than water.

What does the word amphipathic mean?

have polar and non polar regions

What are properties of phospholipids?

: Fatty acids repel water and are referred to as being hydrophobic.
: Phosphate group is attracted to water and is referred to as being hydrophilic.

monosaturated meaning in fatty acids?

having a single bond in their carbon chain.

What fatty acids does phospholipids have?

1 saturated
1 unsaturated

How many ester bonds does triglycerides and phospholipids have?

triglycerides have 3 ester bonds
phospholipids have 2 ester bonds

Do triglycerides and phospholipids have glycerol?

yes they both have glycerol.

Do triglycerides and phospholipids have unsaturated and saturated fatty acid structure.

yes

Number of fatty acids in triglycerides and phospholipids?

triglycerides have 3 fatty acids
phospholipids have 2 fatty acids

In phospholipids, one of the fatty acids of a triglyceride is substituted by a?

phosphate-containing group

What are the elements for triglycerides and phospholipids?

triglycerides: C,H,O
hydrophobic: C,H,O,P

Do triglycerides and phospholipids have bilayers?

triglycerides: no
phospholipids: yes

What elements do proteins have?

Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulphur.

How many naturally occurirng amino acids are there?

20

What is a globular protein?

A protein that is spherical and soluble, they have a metabolic function such as enzymes and insulin.

What is a fibrous protein?

long, thin and insoluble. They have a structural function such as collagen.

What do all amino have in their structure?

Amine group
Carboxyl group
Hydrogen atom
R group (side chain) - differs in all amino acids.

What is the bond called when a condensation reaction between 2 amino acids happen?

peptide bond

How are dipeptides formed?

Dipeptides are formed by the condensation reaction of 2 amino acids

When dipeptides form, where does the bond attach between?

amine group and carboxyl group of the other.

How are polypeptides formed?

formed from the condensation reaction of many amino acids

Define the primary structure of a protein?

A polymer of amino acids joined together by condensation reaction in a specific order of amino acids in a polypeptide chain.

Define the secondary structure of a protein?

A polypeptide chain that folds into an alpha helix or beta pleated sheets. These are held by hydrogen bonds.

Define the tertiary structure of a protein?

Polypeptide folds even further to produce a specific 3d structure

the bonds can be hydrogen: between the polar r groups of the amino acids. Easily broken by temperature and Ph abnormalities.

the bonds can be ionic: between an amino acid with a positive charge and an amino acid with a negative charge. If close enough.

the bonds can be disulphide bridges: between amino acids that contain sulphur in the r-group. Strong covalent bonds but broken by reducing agents and pH.

Define the quaternary structure of a protein?

More than one polypeptide chain bonded together. The bonds are the same as tertiary.

The tertiary structure is determined by where these bonds form, which is also determined by?

the sequence of amino acids.

What is the test for proteins?

Firstly add biuret solution.
The result should turn blue to lilac, lilac if proteins are present.

What is the test for carbohydrates - reducing sugar

Heat to 80c with benedict’s solution.
The result should turn blue to brick red precipitate.

What is the test for carbohydrates - non-reducing sugar

Follow benedict’s method, but the solution stays blue.
fresh sample
boil with acid and then neutralise with alkali
heat to 80c with benedict’s
blue to brick red precipitate

What is the test for lipids?

Shake with ethanol
then add water
lipids are present if its a white/milky emulsion

What is the test for starch?

Add iodine
If present, solution turns yellow to blue/black

What elements is water made of?

made up of 2 atoms of hydrogen and 1 atom of oxygen

What bonds are joined together between the hydrogen and oxygen in water?

polar covalent bonds

What charges does water molecules have?

oxygen has slight negative charge
hydrogen atoms have slight positive charge
meaning it is polar/dipolar

why does hydrogen attract to oxygen in water?

because of oxygen’s high electronegativity
the oxygen pulls shared electrons closer giving oxygen a partial negative charge
while hydrogen gains a partial positive charge

What bonds are water molecules attracted to each other?

hydrogen bonds

When water is described as a metabolite, what does this mean?

an essential reactant or product in chemical reactions within living organisms.

What is the explanation and advantage of water being a polar molecule?

exp: it is an universal solvent

adv: transports ions around the body for a faster reaction

What is the explanation and advantage of water being a universal solvent?

exp: water is polar, which allows ions to dissolve for transport.

adv: transports ions around the body for a faster reaction.

What is the explanation and advantage of water being a metabolite?

exp: involved in hydrolysis and condensation reactions

adv: allows metabolic reactions to occur

What is the explanation and advantage of water having a high heat capacity?

exp: takes a lot of heat energy to break hydrogen bonds, the energy is used instead of changing the temperature.
this acts as a buffer.

adv: external - stable environment for organisms: such as fish

internal - maintains stable temperature for enzymes and reactions

What is the explanation and advantage of water having a large latent heat of vaporisation?

exp: takes a lot of energy to break hydrogen bonds, energy is used to change liquid to gas when it evaporates, carrying away the heat energy.

adv: heat energy is lost through evaporation, allowing organisms to cool down.

What is the explanation and advantage of water having a strong cohesion?

exp: attraction between water molecules, the water forms a column for support, water has a high surface tension when in contact with air

adv: column - transport ions in plants

surface tension - habitat for insects.

What is an enzyme?

a globular protein with a specific tertiary structure, which act as biological catalysts and increase the rate of reaction by lowering the activation energy.

what is an anabolic reaction?

a metabolic process that builds up larger, complex molecules, from smaller, simple ones.

What is a catabolic reaction?

a metabolic process that breaks down bigger, complex molecules into smaller, simple ones

almost all reactions in living organisms are catalysed by?

enzymes

what happens to enzymes when they speed up chemical reactions?

they remain unchanged at the end and can be reused.

Enzymes are coiled into a precise 3D shape, how is this determined?

by the tertiary structure

Why are enzymes soluble in water?

because they have hydrophilic R groups on the outside and hydrophobic R groups on the inside.

How is an enzyme’s active site formed?

formed from their tertiary structure

The active site is a ? on the surface of an enzyme to which a specific substrate binds.

depression

The shape of the active site is always what? to the shape of the substrate

complementary