What is a covalent bonding
Formed when an atoms share electrons
What is an ionic bonding
Attractive forces between oppositely charged ions
What does
PANCAKE stand for
Positive anode Negative cathode
What are important anions in biology
.Nitrate ions (NO3-)
.Phosphate ions (PO43-)
.Chloride ions (CL-)
.Hydrogen carbonate ions (HCO3-)
What are important Cations in biology
.Sodium ions (Na+)
.Calcium ions (Ca2+)
.Hydrogen ions (H+)
.Magnesium ions (mg2+)
What bonds do water contain
Hydrogen bonds
What are the important properties of water
1)Water is a polar solvent
2)Water is an excellent transport medium
3)Ice is less dense than water
4)Water is slow to absorb and release heat
.Water is liquid so it cannot be compressed
.Water molecules are cohesive
.Water molecules are adhesive
.Water has a high surface tension
What is meant by water is cohesive
The forces between the molecules stick together
What is meant by water is adhesive
They are attracted to different molecules
Why does water have a high surface tension
The attraction between the water molecules is greater than the attraction between water molecules and the air
What is the difference between glycogen and starch
Glycogen is used as animal storage and starch is used as plant storage
Glycogen has shorter 1,4 glycosidic bonds
Glycogen is more compact
Glycogen is more branched
What are the functions of cellulose?
.Insoluable
.Gives cell Turgidity
.Allows for some movement
What molecule is formed in the hydrolysis of cellulose
B-glucose
What is the difference between Glycogen and cellulose
Glycogen contains a-glucose units whereas cellulose contains both a and b-glucose unit
Cellulose is in plants whereas glycogen is in animals
Describe triglycerides
Hydrophobic
insoluble
Describe phospholipids
Hydrophilic heads and hydrophobic tails
What’s the main difference between triglyceride and phospholipid
A phospholipid has one glycerol, two fatty acids, and a hydrophilic phosphate group
Triglyceride has three fatty acids
Triglyceride has hydrophobic head whereas phospholipid has hydrophilic heads
What are the functions of:
a) Triglycerides
b) Phospholipid
c) Cholesterol
a) Energy store and fat
b) cell membrane and cell signaling
c) Cell membrane fluidity and Steroid hormone
What is the primary structure
The specific sequence of amino acids in a protein
What is the secondary structure
The coiling and pleating of parts of the amino acids
What is the tertiary structure
The overall 3D structure of the protein
what are the Three types of bonding that occur within the R-group in tertiary structure
Disulphate bond
Hydrogen bond
Ionic bond
When do the following bonds occur:
a) Disulphate bond
b) Hydrogen bond
c) Ionic bond
a) Between amine group with sulfate ions (between cysteine groups)
b) between delta +ve and delta -ve R-groups
c) Between completely ionic R-groups
What are the two main types of tertiary structured proteins
Globular and fibrous
What is the structure and function of globular proteins
.Rolled into balls .Usually soluable .metabolic roles Examples of globular proteins .Enzyme .Antibodies .Haemoglobin
What is the structure and function of fibrous proteins
.Form fibrous .Usually insoluble .Structural roles .Examples of fibrous proteins .collagen .Keratin
What is a quaternary structure
Give an example
a protein made of more than one polypeptide
Haemoglobin and collagen
What is the structure and function of haemoglobin
.Globular .Soluable .Many amino acids .Contains prostheic group (Haem) .Alpha helix
What is the structure and function of collagen
.Fibrous .insoluable .35% glycine .No prosthetic group .Has a left handed helix structure
What are the properties of collagen
.High tensile strength
.insoluable
.not elastic
.flexable
What are
a) glycoproteins
b) lipoproteins
a) protein with a carbohydrate prosthetic group
b) protein with lipid prosthetic group
What are the properties of glycoproteins
.Water holding
.Thyre slippery and viscous
.Helps mucus produced in the stomach protect the protein wall from digestion
What are the properties of Lipoproteins
.Important in the transport of cholesterol in the blood
They have a high density (HDL) and low-density lipoproteins (LDL)
HDLS contain more proteins than LDLS hence why they are denser
What is a nucleotide made up of
Phosphate group
sugar
nitrogenous base
What is ATP
A nucleotide that has:
three phosphate groups
ribose sugar
adenine base
What is the removal of the third phosphate group catalysed by
ATPase
What happens when energy is needed from ATP
A third phosphate group is taken off
When the third phosphate is removed what does the ATP molecule break up into
ADP +Pi
What are nucleic acids
Polymers made up of many nucleotides monomer units that carry all the information needed to form new cells
What are the two main types of nucleic acids in our body
DNA and RNA
What is the difference between pyrimidines and purines
Pyrimidines have a single one ring nitrogenous base whereas purines have a double nitrogenous base ring
What are the three different types of pyrimidines
Thymine
Cytosine
Uracil
What are the two different types of purines
Adenine
Guanine
How do you know whether the sugar is ribose or deoxyribose on the nucleic acid
If the atom attached to the second carbon on the molecule is H its deoxyribose
If the atom attached to the second carbon on the molecule is OH its ribose
How is a long chain of nucleotides formed
The phosphate group that attaches to the carbon number 5 on the sugar below forms attachment with carbon number 3 on sugar above
This pattern keeps going
What are the complementary base pairings
A-T
G-C
which of the complementary base pairing has a:
A)double bond
b)triple bond
a) Adenine and thymine
2) Guanine and cytosine
what is a genome
The entire genetic material of an organism
What is DNA helicase
The enzyme involved in unzipping the two strands of the DNA molecule
What is DNA polymerase
The enzyme involved in DNA replication that lines up and catalyses the linking up of the nucleotides along the template strand
What are the steps for DNA replication
1) You start with a double helix
2) The nucleotides match up to its complementary base
3) When the DNA replicates, DNA helicase unzips the two strands of the DNA molecule and breaks the hydrogen bonds
4) Exposed bases match to another free nucleotide and are zipped back together by the DNA polymerase
5) DNA ligase catalyses the formation of phosphodiester bonds between two strands of DNA
6) This forms two new strands of DNA identical with the original piece
Which out of transcription and translation comes first
Transcription
Where does transcription take place
in the nucleus
Explain the process of transcription
1) RNA polymerase connects complementary RNA bases to the DNA
2) These RNA bases are bonded together to form mRNA
3) mRNA goes out of the nucleus into the cytoplasm where it attaches to a ribosome
4) The ribosome is made of rRNA
5) Ribosome builds our protein the next step called translation
Explain the process of Translation
1) tRNA look for complementary bases (codons) on the mRNA and when they find it, they transfer their amino acid
2) When tRNA eventually leaves, it leaves behind its amino acid
3) These amino acids are held together by a peptide bond
4) At the end of the mRNA, there’s a stop codon
What are polysomes
Groups of ribosomes, joined by a thread of mRNA, that can produce large quantities of a particular protein
What are the types of gene mutations
1) Substitution
2) Insertion
3) deletion
What do the following types of gene mutations mean:
a) Substitution
b) Insertion
c) deletion
a) You have the wrong base matched
b) Have extra bases added in
c) A base is removed
What is a chromosomal mutation
Changes in the position of entire genes within a whole chromosome
What is a whole-chromosome mutation
The loss or duplication of a whole chromosome
How is sickle cell disease caused
By a change of one base in one codon
What is a mutagen
Give an example of one
Anything that increases the rate of mutation
An example is x-rays
What are Enzymes
Proteins that have very specific shapes and are a biological catalyst
What is meant by an induced fit
The active site changes its shape to bind the substrate
How do enzymes catalyse reactions
They reduce the activation energy
What are the lock and key theory
The model that explains enzyme action by an active site in the protein structure that has a very specific shape
What is formed in the lock and key theory
1) Enzyme-substrate complex
2) Products
What does the enzyme-substrate complex look like
The substrate has to be a complementary shape to fit the active site
What is the induced fit theory
A modified version of the lock and key hypothesis for enzyme action where the active site is considered more flexible
What are enzyme inhibitors
Substances that slow down enzymes or stop them from working
What are the two main types of reverse inhibition
1) competitive inhibitors
2) non competiitve inhibitor
What do the following enzyme reverse inhibitors mean:
a) competitive inhibitors
b) non-competitive inhibitor
a) It’s similar to the shape of the substrate molecule and competes with it for the active site of the enzyme
b) The inhibitor does not compete for the active site but forms a complex with the enzyme or enzyme/substrate complex and changes the shape of the active site so it can no longer catalyse the reaction
What is meant by a reverse inhibition
Inhibition of action if an enzyme by an inhibitor that does not permanently affect the functioning of the enzyme
What is meant by an irreversible inhibition
Inhibition of the action of an enzyme that is permanent and can not be undone
What can affect enzyme activity
PH
temperature
What are regulatory enzymes
Enzymes that have a site that’s separate to the active site where another molecule can bind to have either an activating or inhibitory effect
What are End-product inhibition
A control system in many metabolic pathways in which an enzyme at the beginning of the pathway is inhibited by one of the end products of the reaction