A level WJEC Biology unit 1.1

Definition of a monosaccharide

one sugar

two types of glucose

alpha glucose and beta glucose

what is triose important for?

important in respiration

what is pentose important for?

important within nucleotides

what is hexose important for? and name an example

respiration, glucose is an example of this. Monomers are linked to make dimers and polymers

Name three disaccharides

Sucrose, Maltose, and Lactose

What are polysaccharides?

Large complex polymers. They are long chains of polysaccharides

What are inorganic ions?

Inorganic ions only have no more than one carbon atom

What are calcium ions useful for?

Making bones and teeth hard

What are magnesium ions useful for?

Found within chlorophyll, making them vital for efficient photosynthesis

What are iron ions useful for?

found within haemoglobin in red blood cells, enabling the efficient transport of oxygen

What are phosphate ions useful for?

Component of nucleic acids (DNA + RNA) and ATP

What are nitrate ions useful for?

making nucleotides such as DNA and the nitrogen is used for amino acid formation

What is meant by a polar molecule?

electrons are not shared equally

How is water a polar molecule?

The oxygen end contains more electrons (negatively charged) and the hydrogen is positively charged

How will dipole water molecules bind?

They will bind together forming hydrogen bonds

What is cohesion in water?

Many water molecules together form a lattice and is strong. Hence cohesion is present

What are some properties of water?

Solvent, Transport medium, Chemical reactions, Density

What are lipids?

They are triglycerides (fats and oils)
They contain carbon, hydrogen, and oxygen
Insoluble in water (polar)
Soluble in other solvents such as ethanol

What is glycerol?

Alcohol

What are fatty acids?

Organic molecules containing long hydrocarbons chains and have a -COOH group.

What bonds are found in lipids?

Ester bonds

What are saturated fats?

Saturated fats carry the maximum number of hydrogen atoms and have no double bonds between neighbouring carbon atoms with the hydrocarbon tail. They are solid, animal lipids tend to be saturated. Solid at room temperature.

What are unsaturated fats?

Unsaturated fats have double bonds on the C=C atoms. This produces a kink in the chain. They don't contain maximum number of hydrogen atoms. Most oils are unsaturated. Meaning the melt more easily. Liquid at room temperature.

How do lipids link to heart disease?

Fatty deposits are main causes of heart disease such as atherosclerosis and high blood tension. Lipids combine with protein to make lipoproteins

Product of high saturated fats building up

If high saturated fats or LDL (low density lipoproteins) build up. This leads to atheroma build up in coronary arteries restricting blood flow and oxygen to heart tissue. This can lead to angina and a myocardial infraction. (If arteries become blocked).

Product of high unsaturated fats building up

Higher proportions of unsaturated fats more HDL (high density lipoproteins) which carry harmful fats to the liver to be disposed of. Higher ratio of HDL:LDL, lower risk of CHD and cardiovascular disease.

What are phospholipids?

Two fatty acid tails and a phosphate group (replacing the third fatty acid) phosphate group is soluble in water Hydrophilic head and two hydrophilic tails

What is a protein

Proteins contain only carbon, hydrogen, oxygen, and nitrogen atoms. Proteins are made of monomers called amino acids. There are 20 types of amino acids which make up code for thousands of different proteins. The protein is determined by the sequence of amino acids in the chain. Shape determines function.

What is the part highlighted in green?

The amino group (-NH2) alkaline

What is the part highlighted in red?

The R group, variable group of atoms

What is the part highlighted in blue?

The central carbon

What is the part highlighted in yellow?

The carboxyl group (-COOH) acidic

What is the H?

Hydrogen atom

How are dipeptides and polypeptides formed?

Amino group reacts with carboxyl group (condensation reaction) peptide bond is formed and water eliminated.

What are the four levels of structure of protein?

Primary, secondary, tertiary, and quaternary

What are primary proteins?

Sequence of amino acids in a polypeptide chain. Determined by DNA. Held with peptide bonds.

What are secondary proteins?

Hydrogen bonds twist and fold and form an alpha helix (single strand) or beta pleated sheets (two strands). Increase stability and amino acid fold into repeating pattern.

What are tertiary proteins?

Alpha helix folded and twisted further. 3D structure. Bonded by ionic, disulphide, covalent, hydrophobic, and hydrogen bonds. These maintain the structure and shape. Enzymes have a tertiary structure. Bonds also maintain active site shape.

What are quaternary proteins?

Combination of two or more tertiary polypeptide chains and non-protein groups (haem group). Held together by non-covalent bonds (hydrogen bonds, ionic bonds, and hydrophobic interactions) and also covalent disulphide bonds. Form large complex molecules such as haemoglobin. Haemoglobin has four peptide chains.

What is meant by globular classification?

Compact
folded in 3D shape
can be tertiary or quaternary
soluble in water
enzymes are globular

What is meant by fibrous classification?

Polypeptide in parallel sheets/ chains with numerous cross linkages
insoluble in water, strong and tough
structural functions
Keratin is fibrous

What is a conisation reaction

Joins monomers together to form polymers. Water and bonds are formed

What is a hydrolysis reaction

Polymers broken down back into monomers. Requires water and breaks bonds.

What is starch

Most commonly found in photosynthesising cells, in leaves, and storage cells in seeds and organs. It is compacted and dense, insoluble grains stored in special organelles called amyloplasts.

What does starch consist of

Two different polysaccharides, amylose and amylopectin.

What is amylose?

a long chain of alpha glucose molecules joined together by 1,4 glycosidic bonds

What is amylopectin?

a long chain of alpha glucose molecules joined together with 1,4 glycosidic bonds but with the occasional 1,6 glycosidic bond. The additional 1,6 bonds cause amylopectin to have side branches with more accessible ends

Why can amylose only be broken down slowly

it only has two accessible ends

why can amylopectin be broken down faster

is has many accessible ends

is amylose used as a long- or short-term store of energy?

long term store, as it can only be broken down slowly

is amylopectin used as a long- or short-term store of energy?

short term store, as it can be broken down quickly

What role does cellulose have?

A structural role within organisms such as plants

What is cellulose composed of?

many thousands of beta glucose molecules joined by 1,4 glycosidic bonds

What does cellulose do to cells

makes them turgid

What is chitin?

a large structural polysaccharide made from chains of modified glucose. Chitin is found in the exoskeleton of insects, the cell walls of fungi and certain hard structures in invertebrates and fish

What is the role of chitin?

Protects and gives mechanical support to soft bodied organisms.

What are some properties of chitin?

Translucent
Resilient
Tough