Molecular Biology Flashcards
What is Avogadro’s constant
6.022 × 10²³
Define Monomer
A singular unit, that when combined with other units forms a polymer
Define Polymer
Molecules made from multiple monomer units combined together
what is the name of the monomer for carbohydrate molecules
Monosaccharides
what is the name of the polymer for carbohydrate molecules
Polysaccharides
Monomer name for proteins
Amino acids
Polymer name for proteins
Polypeptides
Monomer name for nucleic acids
Nucleotides
polymer name for nucleic acids
DNA and RNA
Name the process by which monomers are converted into a polymer
Polymerisation
Define Condensation
A reaction forming chemical bonds between monomers, releasing a water molecule.
Define Hydrolysis
A reaction breaking chemical bonds between monomers using a water molecule.
what type of attraction is hydrogen bonding
Permanent dipole to permanent dipole attraction
When does a hydrogen bond occur
When a hydrogen atom is covalently bonded to a highly electronegative element such as nitrogen, oxygen or fluorine.
Give 3 examples of monosaccharides
Glucose, Fructose, Galactose
Give 3 examples of disaccharides
Sucrose, Maltose, Lactose
Give 2 examples of structural polysaccharides
Cellulose and Chitin
Give 2 examples of storage polysaccharides
Glycogen and Starch
Give Monosaccharide general formula
(CH2O)n
What are the names of Glucoses isomers
Beta Glucose and Alpha Glucose
where is fructose found
In fruits and nectar
How is maltose formed
Two glucose molecules joined by an alpha 1-4 glycosidic bond.
How is sucrose formed
glucose and fructose joined by an alpha 1-4 glycosidic bond.
How is lactose formed
galactose and glucose joined by a beta 1-4 glycosidic bond
What are monosaccharide’s with 3 carbon atoms called
Trioses
What are monosaccharide’s with 5 carbon atoms called
Pentoses
What are monosaccharide’s with 6 carbon atoms called
Hexoses
Which isomer of glucose forms glycogen
Alpha Glucose
Which isomer of glucose forms starch
Alpha Glucose
Which isomer of glucose forms cellulose
Beta Glucose
why are glycosidic bonds formed?
Make the monosaccharides more suitable for transport and have less effect on a cell’s osmolarity.
How are disaccharides and polysaccharides formed
when two (-OH) groups interact to form a strong covalent bond (glycosidic bond)
Where is the OH on alpha glucose
On the bottom
Where is the OH on Beta Glucose
On the top
Why are starch and Glycogen storage Polysaccharides
They are compact so large quantities can be stored and they are insoluble so will not have an osmotic effect.
What % of starch is Amylose
10 - 30%
What % of starch is amylopectin
70 - 90%
What shape does Amylose take on
A long unbranched Helix - Shaped chain made from alpha glucose molecules joined by alpha 1-4 glycosidic bonds
What shape does Amylopectin take on
Highly branched, long chains of Alpha glucose joined by alpha 1-4 glycosidic bonds with alpha 1-6 glycosidic bonds between branches.
What shape does glycogen take on
Highly branched and not coiled. It is more branched than Amylopectin.
Where are there high concentrations of glycogen
Liver and Muscle cells as cellular respiration rate is high there.
Benefits of branches on storage polysaccharides
Allows more free ends where glucose molecules can be added or removed, allowing for condensation and hydrolysis reactions to occur more rapidly.
What shape does cellulose take on
Long chains of beta glucose joined by beta 1-4 glycosidic bonds, with consecutive beta glucose molecules rotated 180 degrees. This forms many hydrogen bonds too increasing strength.
How do water and solutes leave or reach the cell membrane
The cellulose fibres are freely permeable.
What are Lipids known as
Macromolecules
What atoms are Lipids made up of
Carbon, Hydrogen, Oxygen
Give two properties of Lipids
Non-Polar and Hydrophobic
What are the names of the two groups of Lipids
Triglycerides and Phospholipids
What monomers make up Triglycerides (and how much of each)
3 Fatty Acid molecules bonded to a Glycerol molecule
What two different versions of fatty acid chains are there
Saturated (mainly animal fat) or Unsaturated (mainly vegetables)
Name the two versions of Unsaturated fatty acids
Monounsaturated and Polyunsaturated
What is the name for unsaturated fatty acids whereby the H atoms are on the same side of the double bond
Cis-Fatty Acids
What is the name for unsaturated fatty acids whereby the H atoms are on opposite sides of the double bond
Trans-Fatty acids
Can Cis fatty acids be metabolised by enzymes
Yes
Why are trans fats not metabolised
They cannot form enzyme - substrate complex’s
How are triglycerides formed
Esterification
How does an ester bond form
When a hydroxyl (-OH) group of glycerol bonds with a carboxyl (-COOH) group of fatty acids.
What type of reaction is the formation of an ester bond
Condensation reaction
How does triglycerides being hydrophobic help with energy storage in cells
They do not cause osmotic water uptake in cells, so more can be stored
In what form do plants store their triglycerides
As oil in seeds and fruit
In what form do mammals store triglycerides
As oil droplets in adipose tissue (helps them survive when food is scarce)
What part of nerve fibres do triglycerides make up
The myelin Sheath (Speeds up nerve impulses)
What does the adipose tissue layer below the skin act as
Insulation against heat loss
How does the adipose tissue layer contribute to buoyancy
It has a low a density, allows animals to float more easily
How are organs protected with triglycerides
Adipose tissue layer in mammals contains triglycerides which help protect organs from risk of damage
Name a major component of cell surface membranes
Phospholipids
Are fatty acid tails hydrophilic or hydrophobic
Hydrophobic
Are phosphate heads in phospholipids hydrophilic or hydrophobic
Hydrophilic
What is a Phospholipid comprised of
2 fatty acid tails and a phosphate head, bonded to a glycerol molecule
What is a polymer that has both hydrophobic and hydrophilic parts called
Amphipathic
What do phospholipids form in water
Monolayers or Bilayers
How is a hydrophobic core created on a cell membrane
when a phospholipid bilayer forms, hydrophobic fatty acids face inwards and phosphate heads face outwards.
What does a bilayer act as
A barrier to water soluble molecules
How do other objects pass through bilayer
Other objects other than water soluble molecules (e.g. Glucose) can pass through the hydrogen bonds between the hydrophilic heads
How will the cell membrane being made up of mainly saturated fatty acids affect it
Will be less fluid
How will the cell membrane being made up of mainly unsaturated fatty acids affect it
Will be more fluid
Are phospholipids polar or non-polar
Polar (have a polar phosphate head)
Are triglycerides polar or non-polar
Non-Polar
How many water molecules each are released during the formation of phospholipids and triglycerides
3
Function of Triglycerides
Energy Storage
Function of Phospholipids
Cell membrane component
Are bond between carbon and hydrogen in a saturated fatty acid chain all single or all double
Single
How many hydrogens is each carbon bonded to in a saturated fatty acid chain
2
What is the difference between a saturated and unsaturated fatty acid chain
Unsaturated chain contains a Carbon - Carbon double bond
How does the c-c double bond affect the chain in an unsaturated chain
Causes the chain to have a kink (bend)
Why is an unsaturated chain known as ‘unsaturated’
Does not have the maximum number of hydrogens possible
Why is an saturated chain known as ‘saturated’
has the maximum number of hydrogens possible
How many hydrogens each can the carbon atoms in the carbon - carbon double bond of the unsaturated chain bond to
1
What do triglycerides form in cells
Insoluble droplets (fatty acids on inside and glycerols outside)
