The Chemical Composition of Cells - Biomolecules

Chapter Two: Nelson Biology

All living organisms are made of the same basic chemical

molecules!!• Most matter found in living organisms

is called Organic as it contains Carbon.

• Carbon usually joins with Hydrogen, Oxygen and sometimes Nitrogen and Phosphorous.

• Inorganic compounds are all other compounds (e.g. water, minerals).

Vitamins

• Organic molecules that are needed by the body

• Fats help the body absorb vitamins.• Either fat soluble (A, D, E and K) or

water-soluble (B or C). • Your body cannot store water-soluble

vitamins and they need to be eaten every day.

• Read BioBox 2.1 (p.36)

• Inorganic compounds• Present in the food we eat and incorporated

into many structures of the body.• Where in the body would we find the

following minerals?- sodium- calcium- iron- iodine- fluorine

Minerals

Biomacromolecules

• Break down the word:Bio –Macro –Molecules -

• The four main biomacromolecules are:

ProteinsCarbohydrates

Lipids

Nucleic Acids

• Nitrogen-containing organic molecules that are essential for life!!! (structure and function).

• Also contain carbon, hydrogen and oxygen.

• Amino Acids are the building blocks of proteins (polypeptides)!

• Think back to Year 10 – How many different amino acids are there?

Proteins

• Amino acids are formed from C, H, O and N molecules.

• They join together to create polypeptide proteins.

• The order and number of amino acids determines the type of protein produced.

• Your genes determine the order of amino acids.

Amino Acids

• Regulating movement (e.g. Channel Proteins p. 41)

• Structure (e.g. keratin, collagen)• Controlling metabolism (e.g. enzymes)

Functions of proteins

• These are the most abundant organic compound in nature.

• Composed of Carbon, Hydrogen and Oxygen

• Important energy source- starch in plants- cellulose in plants - glycogen in animals

Carbohydrates

Carbohydrates

Monosaccharides Disaccharides Polysaccharides

GlucoseStarch, Glycogen

and CelluloseSucrose

Nucleic Acid

• DNA – Deoxyribonucleic Acid• RNA – Ribonucleic Acid• In prokaryotes it is found in the

cytoplasm or in plasmids (small rings).• In eukaryotes it is found mainly in the

nucleus, but also in mitochondria and chloroplasts.

• Consists of sugars, phosphates and nitrogenous bases.

• There are four nitrogenous bases – A, C, T, G.

• What do these letters stand for?• According to the Base Pairing rule,

which base pairs with which?• A nucleotide consists of a sugar,

phosphate and a base.

• All living things have nucleotides – it’s just the arrangement of bases, order of nucleotides and amount that makes us different!

• DNA Gene Protein Function!

DNA vs RNA

DNA RNA

• These are your fats and oils. • They also include steroids and waxes.• They are insoluble in water.• Lipids are used for energy storage,

protection, membrane production and sending messages.

Lipids

• Triglyceride lipids are composed of:- three fatty acids- one glycerol

Triglyceride Lipids

It all depends on the bonding!

• Fats can be saturated or unsaturated.• Saturated fats have single bonds between the

atoms which are strongly attracted.• What problems arise when fats are saturated?

(Hint: Think about the bonding)• Unsaturated fats have double bonds between

the atoms which are more easily broken down. Why?

It all depends on the bonding….

Note: If there are many double bonds between the carbon atoms then it is described as polyunsaturated. •What name would we give to an unsaturated fat with only one double bond?

Substance tested for: Biochemical test used: Outcome:

Monosaccharide (glucose) Benedict’s Solution

Starch Iodine

Lipid Sudan IV Indicator Pink-Red

Protein Biuret Reagent

Testing for Biomacromolecules

• Use pages 31 and 32 (if you truly need to) to complete the following table.

Substances in plant and animal cells

Organelle: Substances it contains or is made of:

Nucleus

Cell Wall

Vacuole

Cytoplasm

Mitochondria

Chloroplast

Plasma membrane

Chloroplast