Water (A1.1) + Nucleic Acids (A1.2) + Carbs and Lipids (B1.1) + Proteins (B1.2) Flashcards
Define a hydrogen bond
force when a slightly positive hydrogen atom in one polar molecule is attracted to slightly negative atom of another polar molecule
Describe tertiary structure disulphide bonds between R-groups (3)
disulphide bond between amino acids with sulphur atoms
e.g cysteine and methionine
strongest covalent bonds
Chargaff’s results (2)
concentration/amount of adenine equal/similar to thymine
concentration/amount of cytosine equal/similar to guanine
Describe lactose (2)
glucose + galactose molecule
joined by glycosidic bond
Function of insulin (2)
regulates amount of glucose in bloodstream in response to high glucose levels
binds to receptors on cells - allows glucose to enter cells to be used or stored
How are chromosomes formed from nucleosomes (3)
nucleosomes joined together by linker DNA
nucleosomes stacked onto each other
stacks form chromosomes
Why does ice float on water (2)
ice is less dense as water
pattern of hydrogen bonding of ice is less dense
Explain surface tension of water (2)
cohesion between water molecules > attraction between water and floating object
object must break hydrogen bonds to break the surface of water
Applications of glucose being soluble (2)
polar so able to dissolve in water
dissolves in plasma - can be transported in blood, OH groups bond with water in plasma
Isomers of glucose (2)
alpha-glucose
beta-glucose
Name of bond between amino acids
peptide bond (type of covalent bond)
Define essential amino acids (2)
amino acids which the body cannot produced + must be obtained from diet
9/20
Number of carbon atoms for hexose (2)
6
e.g glucose, fructose
Define monounsaturated fatty acids (3)
have one double bond in hydrocarbon chain
causes a bend in the chain
liquid state at room temp. - bends make it difficult for molecules to pack together
Importance of an amino acid order
gives the protein its function
Directionality of DNA in DNA transcription (2)
nucleotides added to 3’ end of polymer
5’ phosphate of free nucleotide links to 3’ end of growing polymer
Define the Goldilocks Zone (2)
habitable zone around a star
location depends on size of star, amount of energy it emits, size of planet
Buoyancy as a physical property of water (2)
buoyancy = force exerted upward by fluid which counteracts gravity
density of object < density of liquid = buoyancy force > gravity = object will float
Why is glucose chemically stable (2)
ring structure - atoms are bonded to minimise strain + allows for strong covalent bonds
hydroxyl groups - forms bonds with water molecules (stable in aqueous solution) + prevents glucose from undergoing reactions
Define cis unsaturated fatty acids (2)
hydrogen atoms attached to carbon atoms around double bond are on same side
creates bend
Define a pyrimidine (4)
Thymine
Cytosine
Uracil
has one ring
Define unsaturated fatty acids (3)
hydrocarbons have one or more double bonds
causes bends in shape
liquid at room temp. - bends make it difficult for molecules to pack together
Strands of DNA nucleotides in relation to each other (2)
(anti)parallel - parallel but run in opposite directions
one strand ends with phosphate group other ends with deoxyribose (pentose sugar)
Examples of hydrophobic substances (2)
non-polar molecules (not positive or negative)
lipids
Examples of hydrophilic substances (2)
glucose
positive or negative ions (e.g sodium + chloride ions)
Describe the secondary structure of proteins (2)
the folding patterns that occur within the polypeptide chain
hydrogen bonds between O and H atoms on adjacent amino acids form structure
Features of glycogen (2)
insoluble due to large molecular size - does not affect osmotic concentration of cells
branched structure - can be easily hydrolysed to produce glucose
Features of lipids (3)
hydrophobic + insoluble in water - non-polar
dissolve in non-polar solvents - non-polar solvents have similar polarity to lipids
contains carbon, hydrogen, oxygen
Directionality of DNA in DNA translation (3)
ribosome reads RNA sequence
ribosome that carries out translation moves along RNA to 3’ end
5’ to 3’ directionality
Oxidisation as a property of glucose (3)
addition of oxygen to a molecule
loss of hydrogen atom
loss of electrons to another atom/ion
Applications of specific heat capacity of water (2)
aquatic habitats are more thermally stable
helps mammals maintain constant body temperatures
Define the tertiary structure of proteins (2)
folding of the polypeptide chain into a 3-dimensional structure
stabilized by interactions between R-groups of amino acids
Describe tertiary structure ionic bonds between R-groups (4)
ionic bonds between positive + negatively charged R-groups
R-group binding with hydrogen ion = positively charged
R-group losing a hydrogen ion = negatively charged
ionic bonds are more sensitive to pH due to involvement of H+
Name 2 types of secondary structure (2)
alpha helix
beta pleated sheet
Amylopectin property (3)
branch shape allows amylopectin to be more packed together - allows for more efficient storage of glucose
adding + removing glucose is quicker since branch shape has more ends
major component of starch
Materials used in the Hershey-Chase experiment (3)
virus - T2 bacteriophage
bacteriophage inner DNA coated in radioactive phosphorous
bacteriophage outer protein coated in radioactive sulfur
Application of property of glucose being chemically stable (2)
improves structural role of cellulose in plants
helpful in starch and glycogen for storage
Tryglycerides function/characteristics (4)
energy storage - chemically stable so energy not lost
used as insulators to retain heat
liquid at body temperature - can act as shock absorbers
release twice as much energy per gram in respiration than carbs
Describe Hershey-Chase experiment (5)
bacteriophage added to bacteria
blender separates bacteriophage capsid from DNA in bacteria
centrifuge separates bacteriophage from virus to allow investigator to detect radiation location
Phosphorous - virus capsid in liquid is not radioactive, bacteria are
Sulfur - viruse capsid in liquid are radioactive, bacteria are not
Tetranucleotide hypothesis (2)
DNA contains repeating sequence of 4 bases (4 nucleotides occur in equal amounts)
DNA was single-stranded
Name of bond formed between glycerol and fatty acid
ester bond
Functions of codons in genes (3)
most codons specify a particular amino acid
one codon signals that protein synthesis should start
3 codon signal that protein synthesis should stop
Collagen function
provides structural support to tissues + maintains their shape
Define a tryglyceride (4)
non-polar macromolecule + most common type of lipid
formed from one molecule of glycerol + 3 fatty acids
glycerol stays the same but there are different fatty acids
fatty acids = carboxyl groups (COOH) with a hydrocarbon tail
Hershey-Chase experiment results (3)
bacteriophages with radioactive phosphorous infected non-radioactive bacteria, all infected cells became radioactive
next-generation of bacteriophages produced from infected bacteria were all radioactive
bacteriophages coated in radioactive sulfur + virus coats separated = no radioactivity inside infected cell
Phosphate group nucleotide diagram
O-
|
O- – P – O –
||
O
Role of glycoproteins in cell to cell recognition (2)
acts as markers on the surface of cells so they can be identified
e.g immune cells attack foreign cells with different glycoproteins
Deoxyribose sugar nucleotide diagram
– CH2
| O
CH CH – N
CH CH
| |
OH OH
Define a phospholipid
glycerol molecule with a phosphate group and 2 fatty acids
phosphate head is hydrophilic when fatty acids are hydrophobic
Define a disaccharide
2 monosaccharides linked together
What happens after a polypeptide chain is synthesised (2)
protein folding - adopts specific 3D shape which corresponds to its function
influenced by sequence of amino acids, hydrogen + ionic bonding, hydrophobic interactions
Shape which chains of carbon atoms can form (2)
rings
zig zag shape
Bases in DNA (4)
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
Terms used to describe different arrangement of unsaturated fatty acids (2)
cis
trans
Cellulose characteristics (3)
structural sugar in plants
strong - hydrogen bonds between chains create lattice structure
1,4 glycosidic bond
Parts of nucleotides (3)
pentose sugar with 5 carbon atoms
phosphate group : acidic and negatively charged part of nucleic acids
base that contains nitrogen - has either 1 or 2 rings of atoms in its structure
Metabolism in water solvent property (2)
solutes can move + interact
allows for substrates to touch the active sites of enzymes
Properties of glucose (3)
glucose is soluble + small –> easily transported
glucose is chemically stable
yields energy when oxidised
Define polyunsaturated fatty acids (3)
have 2 or more double bonds in hydrocarbon chain
causes multiple bends in chain
liquid state at room-temp - bends make it more difficult for molecules to pack together
Describe amylose (2)
polysaccharide made of glucose monomers linked through alpha-1,4 -glycosidic bonds
helical shaped chain
Number of carbon atoms for pentose (2)
5
e.g ribose
Appearance of nucleosome (2)
length of DNA wrapped twice around cores of 8 histone molecules (2 copies of 4 different histones)
additional histone molecule (H1) reinforces binding of DNA to nucleosome core
Describe the primary structure of proteins (3)
sequence of amino acids
peptide bonds between carboxyl + amine group
determines shape of protein - sequence determines how polypeptide chain will fold