2.1.2 Flashcards
What is a monomer?
A small molecule which joins with others to form a polymer
What is a polymer?
A large molecule made up of many repeating monomers
What is a polar molecule?
A molecule with regions of negative and positive charge
How are regions of charge shown on a diagram?
Delta + or delta -
In water what charge does the oxygen have?
Negative
In water what charge do the hydrogen have?
Positive
Why is water a polar molecule?
Electrons from hydrogen and pulled towards it
How is hydrogen bonding shown on a diagram?
Dashed Line
How strong are hydrogen bonds?
Weak
What are hydrogen bonds?
The bond between negatively charged oxygen and positively charged hydrogens
Property of water beginning with L
Liquid
What happens to hydrogen bonds as the water molecules move?
Constantly break and reform
Water has a _____ viscosity
low
What is viscosity?
How well a liquid flows. Lower viscosity = better flow
Property of water beginning with D
Density
Below 4C is the density higher or lower than above 4C in water
lower
Why is ice’s density less than water’s?
Arrangement of hydrogen bonds
Ice is a _________________ arrangement
tetrahedral
Properties of ice’s structure
- Giant
- Rigid
- Open
Water is a S______
Solvent
Why does water’s polarity make it a good solvent?
It is attracted to other polar/charged molecules
How does water dissolve solutes?
Water molecules cluster around the solute particles, separating he oppositely charged ions
O - H H
l (-) l
H H - O
Will non-polar molecules dissolve in water?
No
What is cohesion?
The hydrogen bonds between water molecules pull the molecules towards each other
What is tension?
A force that tends to stretch something
What is adhesion?
Where water molecules are attracted to surfaces such as in tubes
What is specific heat capacity?
The energy needed to raise the temperature of 1 gram of something by 1C
Does water have a high or low specific heat capacity?
High
What is the specific heat capacity of water?
4.184 kJ / kg / K
Why does water have a high specific heat capacity?
Hydrogen bonds
Does water experience rapid temperature changes?
No
What is latent heat of vaporisation?
The amount of energy a substance can absorb before it changes to a gas
Does water have a high or low latent heat of vaporisation?
High
Why does water have a high latent heat of vaporisation?
Hydrogen Bonds
What is the latent heat of vaporisation of water?
2.26 MJ / Kg / K
Water is a R_________ in many reactions
Reactant
2 examples of reactions where water is a reactant
Photosynthesis
Hydrolysis
What are the 4 roles of water?
- Solvent
- Transport Medium
- Coolant
- Habitat
What is the role of water being a liquid?
- Habitats (rivers, lakes)
- Transport Medium (blood, vascular tissue)
Reaction Medium
Forms tissues
What is the role of water’s density?
- habitat
- stable environment
How does the density of water create a stable environment?
Ice is less dense so it floats
What is an advantage of ice forming at the top of bodies of water?
Provides insulation
What is the role of water being a solvent?
- Allows molecules to move around and react with each other
- transport medium
Role of water’s surface tension
Allows insects such as pond skaters to walk on water
What is capillary action?
The process where water rises up a narrow tube against gravity
What is the role of water’s cohesion?
Capillary action in plants (xylem)
Role of water’s high specific heat capacity
Gives organisms a stable temperature in order to live (reactions)
habitat (gives aquatic organisms a stable environment)
Role of water’s high latent heat of vaporisation
Coolant
How does water’s latent heat of vaporisation make it a coolant?
Mammals sweat cool skin
Water evaporating from mesophyll cells cool plant
Role of water being a reactant
Photosynthesis
hydrolysis
synthesis of large biological molecules
What are the main components of biological molecules?
Carbon, Oxygen, Hydrogen, Nitrogen + others (sulfur, phosphorus)
What reaction takes place to make a polymer?
condensation
What are the products in a condensation reaction?
Polymer + water
What is a condensation reaction?
A reaction where two molecules are joined together with a covalent bond, forming a larger molecule and water
What reaction takes place to break a polymer?
hydrolysis
What is the equation for a hydrolysis reaction?
Polymer + water —> monomer + monomer
What is a hydrolysis reaction?
A reaction where the covalent bond between two molecules is broken with the addition of a water molecule
What are the two types of carbohydrates?
Sugars
Starches
What is a sugar?
Sugars are small carbohydrates (one or two units)
e.g glucose
What is a starch?
Large, long chain carbohydrate made up of many units
e.g glycogen
A sugar made of one unit is called a _____________
Monosaccharide
A sugar made of two units is called a __________
Disaccharide
Starch made of many units is called a _________
Polysaccharide
What is the usual general formula of a carbohydrate?
Cx (H2O)y
What is the function of most carbohydrates?
Energy sources / stores, and support.
Carbohydrates make up a large proportion of ________________ compounds
organic
What is the formula of glucose?
C6H12O6
Glucose is a h_____ monosaccharide
hexose
What are the two variations of glucose?
Alpha
Beta
Glucose in _____________ in non polar substances
insoluble
Glucose is an _______ ______ in animals and plants
energy store
Why is glucose soluble?
So it can be transported
What is the difference between a-glucose and b-glucose?
a - glucose = H
OH
b - glucose = OH
H
What is an isomer?
Molecules of the same molecular formulae but different arrangement of atoms
Ribose is a _______ monosaccharide
pentose
On which carbon is the CH2OH bonded to
C4
What structure do pentose monosaccharides form?
Ring Structure
Name two important pentose monosaccharides
Ribose
Deoxyribose
What is the difference between ribose and deoxyribose?
Deoxyribose has 2 hydrogens bonded to C2, while ribose has an Oh and a H
How are disaccharides formed?
Condensation reactions
What is a glycosidic bond?
A covalent bond formed between two carbohydrates from a condensation reaction
What is maltose made of?
Two alpha glucose
What type of glycosidic bond is in maltose
1 - 4
What is sucrose made of?
a - glucose, b - fructose
What type of glycosidic bond is in sucrose?
1 - 4
What is lactose made of?
b - galactose , a - glucose
What type of glycosidic bond is in lactose?
beta 1 - 4
What is a reducing sugar?
Reducing sugars donate electrons during a redox reaction
Are reducing sugars oxidized or reduced in a redox reaction?
oxidized
Do reducing sugars show results in a benedicts test?
Yes
Do non reducing sugars show results in a benedicts test?
No
What is an aldehyde functional group?
H
R - C = O
What is a ketone functional group?
R
R - C = O
Reducing sugars are _______ sugars
simple
Examples of reducing monosaccharide
Glucose
Fructose
Galactose
Examples of reducing disaccharides
maltose
lactose
What is a non-reducing sugar?
Sugars without an aldehyde functional group
Example of non - reducing sugar
Sucrose
What is a polysaccharide which contains the same monosaccharide called?
homopolysaccharide
What is a polysaccharide containing multiple monosaccharides?
Heteropolysaccharide
What is starch?
A polymer of a-glucose
What are the two molecules of starch?
Amylose
Amylopectin
What is the structure of amylose?
Long, unbranched chain which coils up
Amylose is ______, making it good for storage
dense/compact
What is the structure of amylopectin?
long, branched chain
Why is amylopectin branched?
To increase surface area
What is a benefit of amylopectin being branched?
Easier for enzymes to break it down
Is starch a hetero or a homo polysaccharide?
Homopolysaccharide
Which monosaccharide makes up starch?
a - glucose
AT branches, what is the glycosidic bond in amylopectin?
1 - 6
Starch is a major carbohydrate in _______
Plannts
Starch is _________ in water
insoluble
Plastids meaning
Specialized membrane-bound organelles found in plant cells (e.g chloroplasts)
Glycogen is the main energy storage molecule in _______
animals
Where are the main areas glycogen is stored?
muscle cells and liver
What is the structure of amylose?
Long branched chain.
What glycosidic bonds are present in amylose?
1 - 4
1 - 6 (at branches)
Benefit of amylose having many chains
bigger surface area
Energy released quickly
Why does amylose need more branches then amylopectin?
Animals use energy quicker so energy needs to be released quicker
What is amylose made up of?
a - glucose
What is cellulose made up of?
b - glucose
Alternate molecules are ________
inverted
Cellulose is a ________ chain
straight
What in a plant cell is made up of cellulose?
cell wall
How do cellulose chains bond?
Hydrogen bonds
What is made when cellulose chains bond?
Microfibrils
What is made when bundles of microfibrils cross over?
Macrofibrils
Why is cellulose suitable for cell walls?
The macrofibres it forms are strong
What is a positive result in the benedicts test?
Brick Red
What extra is needed to be done when testing for non-reducing sugars
-Add HCl
- Heat 100C 2 mins
- cool
- add NaHCO3 until pH neutral
Lipids are _____molecules
macro
What ere the three types of lipids?
- Triglycerides
- Phospholipids
- Cholesterol
Why are lipids insoluble in water?
They are not polar
What is a macromolecule?
A very large, organic molecule
What elements do ALL lipids have in common
Carbon, Hydrogen and Oxygen
Why aren’t lipids polymers?
Not made of repeating units
Triglycerides are made up of _ molecule of _______ and 3 fatty acid molecules
1, glycerol
Triglycerides are made up of one molecule of glycerol and _ of ______ ______
3, fatty acids
Are triglycerides polar or non-polar?
Polar
Glycerol is (always/never) the same in a lipid
always
What does it mean if a molecule is saturated?
all bonds are single bonds (no double bonds)
What type of bond forms between the glycerol and fatty acids in a triglyceride?
An ester bond
What is glycerol?
A 3 carbon alcohol molecule
When does an ester bond form?
when an organic molecule (e.g fatty acid) joins to an alcohol by condensation reaction
What is the structure of a phospholipid?
1 glycerol, 2 fatty acids and a phosphate group
What bond joins the phosphate group and glycerol in a phospholipid?
ester
Why is part of a phospholipid hydrophobic while the other part is hydrophobic?
Because only part of it is charged, which is the hydrophilic part?
Which is the hydrophilic part of a phospholipid?
The phosphate group
Which is the hydrophobic part of a phospholipid?
Fatty acids
Name the four functions of lipids
- Membrane formation
- Hormone production
- electrical insulation
- waterproofing
Why are triglycerides useful for storing energy?
They are insoluble so they don’t affect water potential
Name as many functions of triglycerides as you can
- energy source
- energy store
- insulation
- buoyancy
- protection
Why are triglycerides useful for buoyancy?
Fat is less dense than water
Why are triglycerides useful as an energy source?
They can be broken down in respiration to release twice the amount of energy than sugar
Why are triglycerides used to protect organs?
Used to coat delicate organs as it can be used as a shock absorber
What is the main function of a phospholipid?
They make up the cell membrane of all eukaryotes and prokaryotes
Why are phospholipids used in cell membranes?
The hydrophobic tails and hydrophilic phosphate groups form a double layer with tails facing inwards
What is the double layer of phospholipids called which makes up cell membranes?
phospholipid bilayer
How does the phospholipid bilayer act as a barrier against water-soluble substances?
The middle is hydrophobic, making it hard for them to pass through
What are steroid alcohols known as?
sterols
Sterols are (similar/different) to fats and oils
different
Sterols are complex alcohol molecules based on a ____ carbon ring structure
with a ________ group at one end.
four, hydroxyl
What characteristic do sterols share with phospholipids?
dual hydrophilic/hydrophobic
Name 1 example of a sterol
Cholesterol
Cholesterol is a small, hydro(philic/phobic?) molecule
phobic
Cholesterol has a hydroxyl group attached to is which is hydro_____
philic
Cholesterol has a ______ group attached to is which is hydrophilic
hydroxyl
Where is cholesterol made in the body?
liver and intestines mainly
Why is cholesterol useful in cell membranes?
They position themselves between phospholipids which adds stability to the membranes
Why is cholesterol useful for making hormones?
hydrophobic nature allows it to pass through cell membranes
Name 3 examples of hormones made from cholesterol?
- Testosterone
- Oestrogen
- Vitamin D
What test is used to test for the presence of lipids?
The emulsion test
How does the emulsion test work?
- Ethanol extracts the lipid
- Lipids spontaneously comes out of the solution when water is added (lipids hydrophobic)
- forms layer
What is a positive result in the emulsion test?
A layer of cloudy white suspension forms
What are proteins made of?
amino acids
Name 3 functions of proteins
- Structural
- Catalytic
- Carriers and Pores
How are proteins used as catalysts?
Proteins make up enzymes
How are proteins used in the cell membrane?
They form pores to allow molecules through and “carrier proteins” transport the molecules
What is an amino acid?
The monomer of all proteins, all with similar structures
What elements make up all amino acids?
Carbon, Hydrogen, Oxygen, Nitrogen
(some contain sulfur)
Only __ out of over 500 amino acids are found in proteins (proteinogenic)
20
How many amino acids found in proteins can be made from other amino acids in the body?
5
How many amino acids are essential and can only be found in food?
9
How many amino acids are specifically needed in infants and growing children?
6
What is the structure of an amino acid?
- Amine Group
- Central carbon
- single hydrogen bonded to central carbon
- carboxyl group
- R group
What is an R group?
A side chain acting as a functional group?
Called the residual group
One amino acid is called a _____
Monomer
A molecule made of 2 amino acids is called a _______
dipeptide
A molecule made up of more than 2 amino acids is called a ________
polypeptide
Multiple polypeptides make up a _________
protein
