OCR A level Biology- biological molecules

what type of monosaccharide is glucose

hexose monosaccharide

what type of monosaccharide is ribose

pentose monosaccharide

where is the OH group on the 1st carbon in alpha glucose

below the plane

where is the OH group on the 1st carbon in beta glucose

above the plane

what is an allotrope

two forms of the same chemical

what is a disaccharide

two monosaccharide molecules bonded together

what is a polysaccharide

many monosaccharide molecules joined together

what bonds form between monosaccharides

glycosidic bonds

what monosaccharides make up maltose

glucose and glucose

what monosaccharides make up sucrose

glucose and fructose

what monosaccharides make up lactose

glucose and galactose

what is a hydrolysis reaction

the breaking down of a substance using water

what is a condensation reaction

the formation of one product from multiple reactants producing water

where is glycogen found

in animals

what is glycogen made up of

alpha glucose molecules

which glycosidic bonds does glycogen contain

1,4 and 1,6

what is glycogen used for

energy storage in animals

what is starch used for

energy storage in plants

what is starch made up of

amylose and amylopectin

why is starch ideal as a storage molecule

it’s compact/insoluble in water/has no affect on the water potential/can be broken down quickly

what glycosidic bonds does amylose form

only 1,4 glycosidic bonds

what glycosidic bonds does amylopectin form

1,4 and 1,6 glycosidic bonds

where is cellulose found

in the cell wall of plants

what is cellulose made of

beta glucose

what gives cellulose it’s strength

hydrogen bonds form between molecules

what do cellulose molecules form

microfibrils

what do cellulose microfibrils form

macrofibrils/cellulose fibres

what is adhesion

hydrogen bonds forming between two polar molecules

what is cohesion

hydrogen bonds forming between two water molecules

what is a property of water

transport medium/high heat capacity/universal solvent/a medium for chemical reactions/solid form is less dense than it’s liquid form

what are fatty acids composed of

a hydrocarbon tail and an acid head containing a carboxyl group

what is an alcohol

organic molecules containing a hydroxyl group attached to a carbon atom

what bond forms between fatty acids and alcohols

ester bonds

what are triglycerides made of

a glycerol molecule bonded to three fatty acids

what state is a saturated fatty acid at room temperature

a solid

what is a saturated fatty acid

a fatty acid that only has carbon carbon single bonds

what is a monounsaturated fatty acid

a fatty acid containing one carbon carbon double bond

what is a polyunsaturated fatty acid

a fatty acid with multiple carbon carbon double bonds

what state are monounsaturated and polyunsaturated fatty acids at room temperature

liquids

what is a phospholipid made of

glycerol attached to two fatty acid chains and one phosphate group

what is the phosphate group

hydrophilic

what are the fatty acid tails

hydrophobic

what is the reagent for reducing sugars

Benedict’s reagent

how do you test for reducing sugars

add excess benedict’s reagent to your solution and heat in a boiling water bath

what is a positive result for the reducing sugars test

the precipitate will turn brick red

what is a negative test for reducing sugars

the solution remains blue

what is the test for non-reducing sugars

add dilute hydrochloric acid to the sample and heat in a water bath, then add an alkali (sodium hydroxide) to neutralise the sample and then add excess Benedict’s reagent and heat in a boiling water bath

what monomer are proteins formed from

amino acids

what elements make up amino acids

carbon, hydrogen, oxygen and nitrogen

what bonds forms between amino acids

peptide bonds

what reagent is used to test for proteins

Buiret reagent

what is the test for proteins

add buiret reagent to the sample and observe the colour change

what is a positive result when testing for proteins

solution turns purple/violet

what is buiret reagent composed of

potassium/sodium hydroxide and copper (II) sulphate

what is a negative result when testing for proteins

a blue solution

what is the primary structure of a protein

the order of amino acids within a polypeptide chain

what is the secondary structure of a protein

the interactions between the amino acids forming alpha helixes or beta pleated sheets

what is the tertiary structure of a protein

the 3D shape of the protein caused by the interactions between r groups

quaternary structure

caused by interactions between different polypeptide chains within a protein

components of an amino acid

carboxyl group, amino group, hydrogen and the r group

what is a globular protein

a spherical protein with hydrophobic interactions on the inside and hydrophilic interactions on the outside making it soluble in water

what are two examples of globular proteins

haemoglobin and insulin

what type of protein is collagen and why

a fibrous protein because it has a long chain of amino acids which are insoluble in water

what are three examples of fibrous proteins

collagen, elastin and keratin

what does TLC stand for

thin layer chromotgraphy

what is used to stain amino acids in TLC and what colour does it stain them

ninhydrin spray stains amino acids purple

what are the monomers of DNA

nucleotides

what does a nucleotide contain

a pentose sugar, phosphate group and a nitrogenous base

which bases are purines

adenine and guanine

which bases are pyrimidines

thymine and cytosine

what is a pyrimidine base

a smaller base with a single nitrogenous ring

what is a purine base

a larger base with a double nitrogenous ring

what bonds form between the sugar phosphate backbone

phosphodiester bonds

which base does adenine bond to

thymine

which base does guanine bond to

cytosine

what’s it called when DNA strands run in opposite directions

they’re antiparallel

which sugar is in an RNA nucleotide

ribose

which sugar is in a DNA nucleotide

deoxyribose

which base is different in RNA than DNA

thymine is replaced with uracil

How many strands is an RNA molecule

1 strand

what is the role of DNA polymerase

to reseal the hydrogen bonds between bases and the phosphodiester bonds in the sugar phosphate backbone

what is the role of DNA helicase

to unwind the DNA and break the hydrogen bonds between bases

how is the leading strand replicated

the leading strand (3’ to 5’) undergoes continuous replication

how is the lagging strand replicated

the lagging strand (5’ to 3’) undergoes discontinuous replication producing Okazaki fragments

semi-conservative replication

each DNA molecule consists of one parent strand and one new strand

what is meant by DNA being degenerate

multiple codons code for each amino acid

how many amino acids are there

20

what is meant by DNA being non-overlapping

there is only one start codon

what is the first stage of protein synthesis

transcription

what is the second stage of protein synthesis

translation

what forms as a result of transcription

an mRNA molecule

what is the role of RNA polymerase

to unwind a portion of the DNA molecule and break the hydrogen bonds between bases

what is the strand that acts as a template known as

the anti-sense strand

how does the mRNA strand leave the nucleus

through pores in the nuclear membrane

what is the name of 3 bases on a tRNA molecule

anticodon

what is the name of 3 bases on an mRNA molecule

codon

what does the tRNA anticodon carry

an amino acid

what is the initiator tRNA anticodon and amino acids

UAC and methionine

what bonds form between the amino acids during translation

peptide bonds

which enzyme catalyses the formation of peptide bonds during translation

peptidyl transferase