Biological molecules Alevel P1

Define Polymer

Large complex molecule made up of repeating units called monomers

define a monomer

small basic molecular unit that joins together in long chains to form polymers

what reaction causes polymers to form

condensation reactions

examples of polymers 

DNA/RNA, Carbohydrates, Proteins 

define a condensation reaction

chemical process where a chemical/covalent bond forms between monomers which releases a molecule of water (H2O) 

what monomer makes up the polymer of protein 

amino acids 

which monomer makes up the polymer of carbohydrates

monosaccharides

what is a hydrolysis reaction

reaction that breaks the chemical bond between monomers by adding a water molecule.

what are the 3 main biological molecules

carbohydrates, proteins and lipids/fats

define a monosaccharide 

simplest form of a carbohydrate, basic subunit making up the polymer carbohydrate consisting of a single unit of sugar 

what chemical elements do monosaccharides contain

carbon, hydrogen and oxygen

give 3 examples of monosaccharides

fructose, galactose and glucose

what’s the chemical formula for glucose

C6 H12 O6

describe the basics of glucose

glucose is a hexose sugar (has 6 carbon atoms) and there are 2 isomers (types of glucose)

what are the names for the two different types of glucose

alpha and beta

give examples of some monomers and the polymer that they form

amino acids form proteins

monosaccharides form carbohydrates

nucleotides form DNA and RNA

what’s the monomer of a carbohydrate

monosaccharides

where is the OH (hydroxyl group) in alpha glucose

bottom right

where is the OH (hydroxyl group) in beta glucose

top right

define a disaccharide

when two monosaccharides join together

when monosaccharides join together what reaction takes place and what happens

condensation reaction meaning a bond of water (H2O) forms and is released leaving oxygen by itself

Because Oxygen is left due to a condensation reaction when monosaccharides join- what bond does it make

glycosidic bond

what’s the word sequence to help remember what monosaccharides join together to make disaccharides 

GOOD LUCK , MATE, FOOD SUCKS 

Good Luck (alpha g+ galactose= lactose) 

Mate (alpha g+ alpha g= Maltose)

Food Sucks (alpha g+ fructose= sucrose)

what monosaccharides join to form maltose

alpha glucose and alpha glucose

what monosaccharides join to form lactose

alpha glucose and galactose

what monosaccharides join to form sucrose

alpha glucose and fructose

define a polysaccharide

complex carbohydrates made up of many monosaccharides joined via glycosidic bonds

what are the 3 main polysaccharides

starch, glycogen and cellulose

where is starch found

only found in plant cells

how do plant cells make glucose - what’s it stored as

make glucose in photosynthesis where its stored as starch

What’s the chemical formula for photosynthesis

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. 

why is glucose stored as starch in plants

because glucose is soluble so can effect osmosis causing cells to loose water therefor its stored as starch which is insoluble

when starch is eaten to provide energy what’s it broken down into and stored as

broken down back into glucose to be stored as glycogen

what two different polysaccharides is starch made off

amylose and amylopectin

what are the main points about starch

• suited for an energy store

• compact

• insoluble

• easily hydrolysed

what are the monosaccharides of amylose and amylopectin

alpha glucose

What’s the main points about amylose (polysaccharide that makes up starch)

• linear structure made of alpha glucose

• glycosidic bonds

• twist into helix shape making it compact to store more glucose

what are the main points about amylopectin (polysaccharide that makes up starch)

• chains of alpha glucose linked by glycosidic bonds

• branched molecule meaning its easily hydrolysed for use during respiration

Where is Glycogen stored

stored in muscles and liver

is glycogen found in animal cells, plant cells, both or neither 

only animal cells 

what is glycogen made up of 

made of alpha glucose 

describe the structure of glycogen

similar structure to amylopectin but has more branches making it more compact and so because it has more free ends condensation and hydrolysis reactions occur more rapidly

main function of glycogen

main carbohydrate storage product of animals

where is cellulose found

found in the cell wall of plant cells only

what is cellulose made of

made of Beta glucose linked by glycosidic bonds

what does cellulose provide

provides strength and rigidity to the cell wall

describe the structure of cellulose

straight unbranched chains that run parallel to each other, each Beta glucose molecule is inverted in respect to its neighbour causing hydrogen bonds to form between the adjacent chains known as cross links which make it really strong

what chemical elements does protein contain

Carbon, hydrogen, oxygen and nitrogen 

amino acids are the monomers of……

proteins

What are the 3 groups that amino acids have

amino group, carboxyl group and variable group

whats in the amino group

H-N-H

what’s in the carboxyl group

COOH

what letter represents the variable group

R

why is there a variable group 

some amino acids will have a different element to create a different type of amino acid 

whats the full structure of a pro

what’s it called when two amino acids join together

Dipeptide

when a dipeptide forms through a condensation reaction creates what type of bond

peptide bond

what reaction needs to take place to break down a dipeptide

hydrolysis reaction

what is a polypeptide

is the polymer of many monomers of amino acids joined together by peptide bonds

what 4 structures do proteins have 

primary, secondary, tertiary and quaternary 

what is the primary structure

sequence of amino acids in a polypeptide chain

what’s a secondary structure

• chain doesn’t remain straight- hydrogen bonds form between amino acids in the chain

• forms either a coil of alpha helix or fold into a beta pleated sheet 

what’s a tertiary structure

• coiled or folded chains are folded/coiled more 

• more bonds form between different parts of polypeptide chain including hydrogen, ionic bons and disulfide bridges 

• proteins made of single polypeptide chain tertiary structure forms their final 3D structure 

what’s the quaternary structure

• some proteins are made of several different polypeptide chains - quaternary structure is the way chains are assembled together 

• proteins final 3D structure 

what are lipids made from

from different components and contain hydrocarbons : carbon, hydrogen and oxygen

what are the two types of lipids

triglyceride and phospholipid

what’s the structure of a triglyceride

a glycerol molecule and 3 fatty acid chains

how do the fatty acids attach to the glycerol molecule

attach in a condensation reaction where 3 h2o molecules are lost to form bonds 

what bonds are formed between fatty acids and glycerol

Ester linkage/ bonds

what properties do a Triglyceride lipid have

• long hydrocarbon fatty acid tails, when broken down lots of energy is released

• insoluble in water - doesn’t affect osmotic potential

• bundle together as insoluble droplets in cells - fatty acid tails face inwards shielding themselves from water with their glycerol head

what does unsaturated fatty acids mean

has one or more double carbon to carbon bond (C=C) causing a kink in chain

what does saturated fatty acid mean

single carbon to carbon bond (C-C) creating a straight chain 

what is the test for lipids

emulsion test

what are the fatty acid tails made of

hydrocarbons

what are the fatty acid tails known as + what does this mean

hydrophobic - repel water/cant mix

where are phospholipids found

found in cell membranes 

what is the structure of a phospholipid

contain a phosphate, glycerol molecule and 2 fatty acid chains

the phospholipids head contains what

phosphate and glycerol 

the head of phospholipids are what

hydrophilic - attracts water

what are the properties of phospholipids

-make up the phospholipid bilayer of cell membrane which controls what goes in and out

-heads are hydrophilic and tails are hydrophobic so form a double layer 

-centre of bilayer is hydrophobic so water soluble substances cant easily pass through it 

-channels made of proteins to allow water molecules across

what are the stages for the emulsion test

• shake test substance with ethanol for about a minute then pour the solution into water

• any lipid will show up as a milky emulsion

enzymes are known as…..

biological catalysts

what does it mean by enzymes being a biological catalyst

they speed up chemical reactions, they catalyse metabolic reactions both at a cellular level and for whole organism

enzyme action can be both what?

intracellular (within the cell) or extracellular (outside cells)

enzymes are a type of what

type of protein

what is the active site

is the part of the enzyme where the substrate molecule bind to

what is important about the active site

it has a specific shape 

what causes enzymes to have a highly specific shape

because they are a tertiary structured protein

when talking about the active site and substrate binding you would say they are…

complimentary

when substrate joins active site what forms

a enzyme substrate complex

define activation energy

minimum amount of energy required for a chemical reaction to occur

what do enzymes do to the activation energy

lower amount of activation energy needed to speed up the rate of reaction

why does the enzyme substrate complex lower activation energy

• if two molecules need to be joined together being attached to enzyme holds them close reducing any repulsion so they can bond easily 

• if enzyme is catalysing a breakdown reaction, fitting into active site puts stain on bonds in substrate so substrate molecule breaks up more easily 

what is the older model called of enzymes

lock and key theory/model

what does the lock and key theory state

one substrate fits one specific active site of an enzyme just like a key fits into a specific lock

as new evidence rose what was the newer version of the lock and key theory

the induced fit model

what does the induced fit model state 

• substrate doesn’t only have to be the right shape to fit active site, it has to make the active site change shape in the right way as well