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A student mixed an unknown substance with water and ethanol. A white suspension formed in the tube. What is present? [1]
Lipids are present
Buoyancy of triglycerides
Fat is less dense than water, it is used by aquatic animals to help them stay aflot
Chloroplast
It is a steroid alcohol - a type of lipid which is not made from glycerol or fatty acids
Cohesion in water
water molecules stick together as a result of hydrogen bonding
Density of water
It provides an ideal habitat for living things.
Describe amylose
It contains alpha glucose, with 1-4 glycosidic bonds and all monomers are in the same orientation.
Describe and explain how the structure and properties of different carbohydrate and lipid molecules suit them to their role as energy storage molecules in plants and animals. [6]
q19
Describe how an enzyme, such as pepsin, breaks down a substrate.
substrate shape is complementary to active site, it then fits into the active site. It is an induced fit and forms enzyme-substrate complex, then products leaves
Describe how to do the emulsion test for lipids and how a positive result would be identified.
mix with / add , ethanol / alcohol , and water ; (goes) cloudy
Describe the formation of a hydrogen bond between two molecules of water and explain why water can form these bonds.
between O and H between electropositive H and electronegative O as it is polar
Describe the formation of a hydrogen bond between two molecules of water and explain why water can form these bonds. [3]
1.between O and H (of adjacent molecules); 2. between, electropositive / δ+ / delta+ (H), and, electronegative / δ- / delta- (O); 3.water molecule, is polar / has charge separation;
Describe the primary level of protein structure.
peptide bonds and the sequence of amino acids
Describe the process of adhesion [2]
attraction of water molecules to the impermeable walls of xylem tissue
Describe the role of cholesterol in cell surface membranes in the human body
Cholesterol binds to phospholipid fatty-acid tails/phosphate heads, increasing the packing of the membrane, therefore reducing the fluidity of the membrane.
Disulfide links
The strongest of attractions, this is a covalent chemical bond that crosslinks different protein strands together, giving someone's hair the natural tendency to be straight or curly
Draw a condensation reaction
Draw a pentose sugar
Draw a saturated fatty acid
Draw a unsaturated fatty acid
Draw an alpha glucose
Draw an beta glucose
Draw glycerol
Draw glycerol
Draw primary structure of a protein
Draw the formation of a triglyceride
Draw the general structure of an amino acid molecule in the space below.
Draw the molecular structure of an amino acid
They can be broken down in respiration to release energy and generate ATP.
Energy source of triglycerides
Its insoluble in water, they can be stored without affecting the water potential of the cell.
Energy store of triglycerides
hydrophilic head and hydrophobic tails (1) hydrophobic part / tails, repelled / AW, by water head / hydrophilic part, forms H bonds with water
Explain how the structure of phospholipids allows them to form the bilayer of a plasma membrane.
idea that the glycogen deposited is, in long chains / not branched, so not compact (which damages liver cells);
Glycogen storage disease type IV occurs when the liver is unable to catalyse the addition of branches of glucose molecules. People with this disease may develop liver damage over time. Suggest why this disease may result in liver damage.
Water requires a lot of energy to change temperature
High specific heat capacity
The phosphate group has a negative charge making polar, however the fatty acid tails are non-polar and are repelled by water.
How do phospholipids behave in water?
Hydrolyse the ester bonds and then both glycerol and the fatty acids can be broken down completely to carbon dioxide and water. Respiration of a lipid produces more water than respiration of a sugar
How do triglycerides break down for respiration?
2
How many hydrogen atoms for one oxygen atom in a carbohydrate?
Very weak bonds; occurs when a hydrogen atom in one molecule is attracted to the electrostatic atom in another molecule
Hydrogen bonds
water loving
Hydrophilic
Water fearing
Hydrophobic
Adipose tissue is a storage location for lipids in whales acting as a heat insulator.
Insulation of triglycerides
Formed when one or more electrons are transferred from one atom to another
Ionic bonds
starch AND glycogen
Name the carbohydrate molecules used to store energy in plants and animals
peptide bond
Name the covalent bond between two adjacent amino acids in a chain of amino acids.
hydrolysis; water is added
Name the type of reaction involved in breaking this bond and describe what happens in this reaction.
subunits quaternary
Polypeptides known as alpha (α) and beta (β) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ form part of the _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ structure of haemoglobin.
Humans have fat around delicate organs to act as a shock absorber.
Protection of triglycerides
primary structure
State the name given to the sequence of amino acids in a protein molecule.
1-4 glycosidic
maltose
State the precise name of the covalent bond that forms between the two glucose molecules and the name of the disaccharide that is formed. [2]
(enzymes are) globular, proteins / polypeptide; hydrophilic / water soluble, (R-)groups on outside (of enzyme);
State why the structure of enzyme molecules allows them to be detected in solution using the biuret test.
facilitated diffusion (1) conversion of ornithine into citrulline creates concentration gradients
Suggest the method by which these molecules move into and out of the organelle during the cycle. Give reasons for your choice
protein/polpeptide
Sulfur atoms are required for the synthesis of which type of biological molecule? [1]
The water molecules at the surface ar ehydrogen bonded to the molecules un
Surface tension in water
secondary
The _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ structure of collagen is described as a left-handed helix because of the direction in which the polypeptide twists.
The phospholipid bilayer
A double layer of phospholipids that makes up plasma and organelle membranes.
The secondary structure of a protein is determined by the arrangement of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ bonds, which stabilise the structure.
hydrogen
The secondary structure of a protein may contain many regions folded in zig-zag patterns known as .....
beta- pleated sheet
Water as a reactant
Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water?
Water as a solvent
many substances dissolve well in water because their polar molecules bond easily with other polar molecules
What are amino acids?
building blocks of proteins
What are disaccharides?
double sugars
What are ester bonds?
bonds between fatty acids and glycerol
What are fatty acids?
carboxylic acids, typically with a single long chain, although they can be branched
What are lipids?
A group of substances that are soluble in alcohol rather than water.
What are polysaccharides made out of?
Hundreds or thousands of monosaccharide monomers bonded together
What are polysaccharides?
polymers of monosaccharides
What are the 3 main groups of carbohydrates?
monosaccharides, disaccharides, polysaccharides
What are the 3 most important lipids?
triglycerides, phospholipids, steroids
What are the different types of disaccharides?
maltose, sucrose, lactose and cellobiose
What are the different types of polysaccharide?
Amylose, amylopcetin and glycogen
What are the features of monosaccharides?
Sweet, soluble in water and crystalline. They are easily oxidised and so are called reducing sugars
What are the features of phospholipids?
The phosphate head is hydrophilic and the fatty acid tail as hydrophobic
What are the functions of triglycerides?
Energy source Energy store Insulation Buoyancy Protection
What are the properties of water?
cohesion and surface tension , high specific heat, high heat of vaporization, density, reactant and solvent
What charge is hydrogen?
positive
What charge is oxygen?
negative
What do carbohydrates contain?
carbon, hydrogen, oxygen
What do carbohydrates do?
They act as a source of energy, as structural units and are also part of other molecules such as nucleic acids
What do lipids contain?
carbon, hydrogen, oxygen
What do nucleic acids contain?
carbon, hydrogen, oxygen, nitrogen, phosphorus
What do phospholipids look like in the presence of detergent?
B
What do proteins contain?
carbon, hydrogen, oxygen, nitrogen, sulfur
What do proteins do?
Help build and maintain cells.
What does amylopectin contain?
it contains 1-4 and 1-6 glycosidic bonds between α-glucose monomers
What does it mean if a fatty acid is saturated?
every C atom is bonded to at least two H atoms, max number of H
What does it mean if a fatty acid is unsaturated?
there is at least one double bond between successive C atoms (liquid at room temp)
What does polar mean?
unequal sharing of electrons
What does the carboyxl group ionsies into?
Into H+ and a -COO- group
What elements are in ATP?
C,H,O,N,S
What elements are in cholestrol?
C,H,O
What elements are in insulin?
C,H,O,N,S
What elements are in sucrose?
C,H,O,N
What happens in a condensation reaction in disaccharides?
Two hydroxl groups line up next to each other from which a water molecule is removed leaving an oxygen atom acting as a link between the 2 monosaccaride units
What happens when 2 disaccharide join?
A condensation reaction occurs to form a glycosidic bond
What is a carbohydrate?
compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body
What is a condensation reaction?
A reaction in which two molecules combine to form a larger molecule, producing H2O as a by product
What is a glycosidic bond?
When two monosaccharide rings are bonded using a C-O-C bond
What is a hetropolysaccharide?
A polysaccharide that contains two different kinds of monosaccharide
What is a homopolysaccharide?
A polysaccharide that contains only one kind of monosaccharide
What is a hydrogen bond?
a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.
What is a macromolecule?
large molecule
What is a molecular formula for deoxyribose?
C5H10O4
What is a monomer?
A molecule that can be bonded to other identical molecules to form a polymer.
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