3.1 Biological Molecules | COMPLETE Flashcards
3.1.1
what are monomers?
two examples
smaller units from which larger molecules are made from
glucose and amino acids
3.1.1
what are polymers?
two examples
molecules made from a large number of monomers joined together
polypeptides and cellulose
3.1.1
define monosaccharides
one example
single sugars which are monomers
glucose
3.1.1
name three monomers
monosaccharides
amino acids
nucleotides
3.1.1
what is a condensation reaction?
a reaction which joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water
3.1.1
what is a hydrolysis reaction?
a reaction which breaks a chemical bond between two molecules and involves the use of a water molecule
3.1.2
what are monosaccharides?
give three examples
the monomers from which larger carbohydrates are made
glucose, galactose and fructose
3.1.2
what bond forms when two monosaccharides undergo a condensation reaction?
glycosidic bond
3.1.2
when are disaccharides formed?
in a condensation reaction between two monosaccharides
3.1.2
glucose + glucose = …
maltose
3.1.2
glucose + fructose = …
sucrose
3.1.2
glucose + galactose = …
lactose
3.1.2
what are the two isomers of glucose?
α-glucose
β-glucose
3.1.2
what is an isomer?
each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties
3.1.2
TRUE OR FALSE
α-glucose has the H atoms above the OH atoms
true
3.1.2
TRUE OR FALSE
β-glucose has the H atoms above the OH atoms
false
left H is above and right H is below
3.1.2
what is a polysaccharide and how are they formed?
two examples
a chain of monosaccharides
formed by the condensation reaction of many glucose units
glycogen and cellulose
3.1.2
what is the basic structure of glycogen?
bonds between carbons 1-4 and 1-6
branches
α-glucose
glycosidic bonds
3.1.2
what is the structure of cellulose?
β-glucose
every other molecule is inverted
glycosidic bond
hydrogen bonds
chains run parallel to each other
3.1.2
what is the biological test for reducing sugars?
add benedict’s solution
add to water bath for five minutes
brick red = positive
3.1.2
what is the biological test for non-reducing sugars?
failed benedict’s test
add hydrochloric acid and boil for five minutes
add equal parts sodium hydroxide to neutralise the solution
add benedict’s and add to a water bath for five minutes
brick red = positive
3.1.2
what is the biological test for starch?
add iodine
black = positive
3.1.2
what is the biological test for lipids?
add ethanol to sample
shake
add water to sample
shake
white emulsion = positive
3.1.3
what are the components of triglycerides?
one glycerol
three fatty acids
3.1.3
what elements are in triglycerides?
carbon
hydrogen
oxygen
3.1.3
describe a glycerol molecule
glycerol molecule:
’’’ H H H
‘ | | |
H - C - C - C - H
‘’’’ | | |
‘’’’ OH OH OH
3.1.3
what group do all fatty acids contain?
COOH
3.1.3
what type of reaction occurs to form a triglyceride?
condensation
3.1.3
what are the bonds in a triglyceride?
three ester bonds
3.1.3
TRUE OR FALSE
the R-group of a fatty acid is always saturated
FALSE
it can be both saturated or unsaturated
3.1.3
what does a phospholipid contain?
two fatty acids
one glycerol
one phosphate group
3.1.3
what are four similarities between triglycerides and phospholipids?
contain glycerol
both have fatty acids
made with carbon, hydrogen and oxygen
ester bonds
3.1.3
what are three differences between triglycerides and phospholipids?
tri = 3 fatty acids, phos = two fatty acids
tri = no phosphate group, phos = one phosphate group
tri = three ester bonds, phos = two ester bonds
3.1.3
what are the properties of a polar head of a phospholipid?
hydrophilic
glycerol and phosphate group
3.1.3
what are the properties of the fatty acid tails of a phospholipid?
hydrophobic
two fatty acid tails
3.1.4
what are amino acids?
monomers which proteins are made from
3.1.4
what is the general structure of an amino acid?
general structure :
R
|
H₂N – C – COOH
|
H
3.1.4
what is NH₂?
amine group
3.1.4
what is COOH?
carboxylic group
3.1.4
what is R?
varied part of the amino acid
3.1.4
what reaction between amino acids creates a polypeptide?
condensation
3.1.4
TRUE OR FALSE
a functional protein may only contain one or more polypeptides
TRUE
3.1.4
what bonds form between R-groups in amino acids?
disulphide
ionic
3.1.4
how many different amino acids are there?
20
3.1.4
what do the bonds in between the R-groups determine?
how the protein will fold
3.1.4
how many stages/structures are there a protein can go through?
4
3.1.4
what happens in the primary structure?
the sequence of amino acids in a polypeptide chain is the primary structure
peptide bonds between amino acids
o-0-o-o-o-0-0-o-0-o-o-0-o-o-0
3.1.4
what happens in the secondary structure?
the polypeptide chain coils to produce an alpha helix or fold to produce a beta pleated sheet
hydrogen bonds between amine group and carboxylic group of two amino acids
3.1.4
what happens in the tertiary structure?
further folding produces a unique 3D shape
the shape is held in place by hydrogen, ionic and disulphide bonds between R-groups
3.1.4
what happens in the quaternary structure?
NOT ALL PROTEINS HAVE THIS LEVEL
made of more than one polypeptide chain
it is folded into an unique 3D shape held by hydrogen, ionic and disulphide bonds
3.1.4
name two examples of proteins with a quaternary structure?
collagen
haemoglobin
3.1.4
what are the two types of proteins?
fibrous
globular
3.1.4
what are the shape, function, solubility of fibrous proteins?
give two examples
long and thin
structural function
insoluble
keratin and collagen
3.1.4
what are the shape, function, solubility of globular proteins?
give two examples
spherical
biochemical function
soluble
haemoglobin and enzymes
3.1.5
what does DNA stand for?
deoxyribonucleic acid
3.1.5
what does RNA stand for?
ribonucleic acid
3.1.5
what is the difference between roles of DNA and RNA?
DNA holds genetic information
RNA transfers genetic information from DNA to the ribosomes
3.1.5
what are ribosomes formed from?
RNA and proteins
3.1.5
what monomer makes up DNA and RNA?
nucleotides
3.1.5
what is a nucleotide made up of?
pentose sugar
phosphate group
nitrogen-containing base
3.1.5
what are the bases for DNA?
adenine
cytosine
guanine
thymine
3.1.5
what are the bases for RNA?
adenine
cytosine
guanine
uracil
3.1.5
what reaction produces DNA?
condensation reaction
3.1.5
what bond is between two nucleotides?
phosphodiester bond
3.1.5
what part does phosphodiester bonds form between?
phosphate group
base
3.1.5
what are the differences between DNA and RNA?
DNA
> double helix/strands
> complimentary base pairs
> A,T,C,G
> longer
> stores genetic information
RNA
> single helix/strand
> nucleobases
> A,U,C,G
> shorter
> carries small parts of genetic info to ribosomes
3.1.5.2
describe the process of semi-conservative replication?
> DNA helicase hydrolyses the hydrogen bonds between the base pairs in the two strands within a double helix
the double helix unwinds and separates
each of the separated parental DNA strands acts as a template
free floating nucleotides within the nucleus are attracted by the complementary base pairs on the template strands
the adjacent nucleotides are joined together to form a phosphodiester bond by a condensation reaction
DNA polymerase catalyses the joining together of adjacent nucleotides
the two sets of daughter DNA contains one newly synthesised strand and one strand from the parental DNA
3.1.5.2
describe the Meselson-Stahl study?
> grew E-coli on a 15N medium
then placed the E-coli on a 14N medium
in each generation they collected a sample and measured the density using a centrifuge
15N would go to the bottom and 14N would go to the top after centrifugation
after generation one: conservative replication was dismissed because there was NOT two lines after centrifugation
after generation two: dispersive replication was dismissed because there was two lines and not one big chunk
3.1.5.2
what were the three theories of how DNA replicates and what they formed?
semi-conservative - half old, half new DNA strand
conservative - entirely new DNA helix
dispersive - patchworks of old and new DNA
3.1.5.2
who theorised how DNA replicates?
Watson and Crick
3.1.5.2
what is the name of how DNA replicates?
semi-conservative replication
3.1.6
what does ATP stand for?
adenosine triphosphate
3.1.6
TRUE OR FALSE
ATP is a nucleotide
derivative
TRUE
3.1.6
what makes up ATP?
ribose sugar
three inorganic phosphates
adenine
3.1.6
what makes a molecule inorganic?
if no carbon is present
3.1.6
how is energy stored in ATP?
in the bonds between the second and third phosphate ions
3.1.6
what is the ATP cycle?
the last phosphate ion of ATP is hydrolysed by ATP-Hydrolase
energy is released
this produces ADP+Pi
ATP-Synthase then joins them back together
3.1.7
list the five properties of water and why they are important
metabolite -> used in chemical reactions
high specific heat capacity -> buffers temperature changes to keep temperature stable
solvent -> reactions can occur and substances can dissolve to be transported
large latent heat of vaporisation -> provides a cooling effect (sweating)
cohesion -> transport water in a continuous column (in xylem)
3.1.7
TRUE OR FALSE
water is a metabolite in many metabolic reactions, including
condensation and hydrolysis reactions
TRUE
3.1.7
FILL IN THE GAPS
water has a relatively ____ heat capacity, buffering changes in
___________
high
temperature
3.1.7
where do the hydrogen bonds form between water molecules?
O–H
3.1.7
name the charges of a water molecule
O = delta minus
H2 = delta positive
3.1.7
why is it a good thing water has strong cohesion between water molecules?
supports columns of water in the tube-like transport cells of plants
produces surface tension where water meets air
3.1.7
water makes up around ___% of a cell’s contents
80%
3.1.7
does water have strong or weak cohesion between water molecules?
strong
3.1.8
where do inorganic ions occur?
in solutions (in the cytoplasm and body fluids)
3.1.8
name four inorganic ions
Iron ions Fe2+
Sodium ions Na+
Phosphate ions PO4 3-
Hydrogen ions H+
3.1.8
what are phosphate ions used in?
(four)
DNA and RNA
ATP
Phosphorylates other molecules making them more reactive
Hydrophilic part of phospholipid bilayer
3.1.8
what are iron ions used in?
(one)
haemoglobin
3.1.8
what are hydrogen ions used in?
(two)
affect on pH and enzymes
chemiosmosis in respiration and photosynthesis
3.1.8
what are sodium ions used in?
(three)
Co-transport
Affect osmosis
Role in action potentials in neurones.
