Chapter 2 Understanding & Application Flashcards
List types of lipids
- fatty acids
- steroids
- triglycerides
- phospholipids
List types of nucleic acids
- DNA
- RNA
- nucleotides
What is anabolism? List examples
building up larger molecules
e.g. photosynthesis
converting amino acids into proteins
What is catabolism? List examples
breaking down larger molecules
e.g. cell respiration
- glycolysis
- nucleic acids –> nucleotides
Benefit of cohesive property of water
- allows surface tension (insects can glide)
- creates chain of water molecules (transport through xylem)
- high heat capacity of water (more energy needed to break these bonds b/w water molecules) –> maintains stable env. for living organisms
Benefit of adhesive property of water
- needed for water to move from roots to leaves - sticks to sides of xylem wall
- capillary action allows blood to move through vessels
Why is water a good solvent?
polarity + H bonding w/ substances
High melting & boiling point of water
- due to H bonds
- causes water to be liquid in most habitats
High specific heat capacity of water
- amount of heat that must be absorbed/released for 1 g of a substance to change its temp. by 1 C
- H-bonds
- protects habitats from lethal temp. fluctuations
High latent heat of vaporisation (coolant)
- amount of heat needed to change 1 g of liquid to a gas
- H-bonds
- as water evaporates, surface left behind is cooler
- allows organisms to cool w/ sweating
- removes heat from body
What type of bond forms b/w monosaccharides?
glycosidic linkages
What type of bond forms b/w amino acids?
peptide bonds
What type of bond forms b/w glycerol & fatty acids in lipids?
ester linkages
What types of bonds form between nucleotides?
phosphodiester bonds
Where do saturated & unsaturated fatty acids originate from?
- saturated = linear, originated from animal source, solid at room temp.
- unsaturated = bent, originated from plant source (oil), liquid at room temp.
Do trans or cis fatty acids have high melting points?
trans have high melting point & are solids at room temp. –> OCCUR IN PROCESSED FOODS
Distinguish b/w fats & oils
FATS
- solids at room temp.
- animal sources
- contain more saturated fatty acids
- e.g. butter
OILS
- liquids at room temp
- plant sources
- contain more unsaturated fatty acids
- e.g. olive oil
State functions of triglycerides
- energy
- storage of energy
- thermal insulation
- protection of organs
- water proofing
- structural roles (e.g. cholesterol)
Structural difference b/w alpha & beta glucose
- OH is DOWN on C-1 in alpha, but UP on C-1 in beta
Outline the structure & function of cellulose
- forms plant cell wall
- polymer of Beta glucose
- linear molecule
- bound in 1-4 arrangement
- tensile strength
Outline the structure & function of glycogen
- in animals
- alpha glucose
- branched molecule
- both 1-4 and 1-6 linkages
- insoluble
- energy storage
Outline the structure & function of starch in plants
- starch is polymer of a-D-glucose
- helical shape
d. storage of glucose/energy in plants
e. storage form that does not draw water
- amylose
- only 1-4 linkages so unbranched - amylopectin
- 1-4 AND 1-6 linkages so branched
How many types of amino acids exist?
many, but only 20 used in living organisms
How many possible amino acid sequences given n number of amino acids?
20^n possible dif amino acid sequences
Distinguish b/w polypeptide & protein
when polypeptide folds into specific 3D structure, it is known as protein
Example of protein (structure & function)
HEMOGLOBIN
- made of 4 subunits, each having 1 polypeptide chain + 1 heme group
- found in red blood cells that transports oxygen from lungs to tissues
Define globular proteins
- polypeptide chain folds up into a compact shape like a ball w/ an irregular surface
- e.g. enzymes
- usually have rounded shape
- FUNCTIONAL PROTEIN
e.g. hemoglobin, insulin, catalase
Define globular proteins
- polypeptide chain folds up into a compact shape like a ball w/ an irregular surface
- e.g. enzymes
- usually have rounded shape
- FUNCTIONAL PROTEIN
e.g. hemoglobin, insulin, catalase
Define fibrous proteins
- simple, elongated 3D shape
- have roles in cell requiring each individual protein molecule to span large distance
- STRUCTURAL PROTEIN
- e.g. collage, myosin, fibrin, actin, keratin
Functions of proteins
- contraction / movement
- enzyme
- hormone
- immune defense
- pigment
- receptor
- storage
- structure
- transport
- catalysis
Why does each cell of an organism have unique proteome?
- cells w/ different functions will produce dif. proteins as dif genes are expressed in dif cells
Why does each cell of an organism have unique proteome?
- cells w/ different functions will produce dif. proteins as dif genes are expressed in dif cells
State the function of rhodopsin
a pigment protein found in rod cell of retina
- extremely sensitive to light & thus enables vision in low light conditions
State the function of collagen
- structural protein
- 3 polypeptides wound together to form rope-like conformation
- used in skin to prevent tearing
- in bones to prevent fractures
- in tendons & ligaments for tensile strength
- the main component of connective tissue
- most abundant protein in mammals
State the function of spider silk
- structural protein
- used to make webs for catching flies / prey
- very high tensile strength
- resists breakage
Define denaturation
the alteration of a protein shape through some form of external stress (e.g. heat / acid) in such a way that it will no longer be able to carry out its cellular function
Outline the effects of heat on protein structure
- disrupts H bonds & non-polar hydrophobic interactions within proteins
- occurs because heat increases the kinetic energy & causes molecules to vibrate so rapidly & violently that bonds are broken
- can lead to altered protein recognition or an enzyme might becomes inactive
Outline the effects of pH on protein structure
- affect state of ionisation of acidic / basic amino acids
- if the state of ionisation of amino acids in a protein in altered then the ionic bonds that help to determine 3D shape will be altered
- leads to protein denaturation
List examples of industries in which enzymes are use
- food production
- food processing
- food preservation
- washing powders
- textile manufacture
- leather industry
- paper industry
- medical applications
How & why are industrial enzymes often immobilised?
- resistance to denaturation
- catalysis can be controlled
- enzyme concentrations higher
- products not contaminated w/ enzymes
Define immobilised enzyme
an enzyme attached to an inert, insoluble material
Methods of enzyme immobilisation
- attachment to surface such as glass (ADSORPTION)
- entrapment in membrane / gel (e.g. alginate)
- aggregation by bonding enzymes together into particles of up to 0.1 mm diameter
State source of lactase enzyme in food processing
obtained from yeast - yeast is cultured, lactase is extracted + purified
Production of lactose-free milk
- lactase added to milk (may be immobilised on surface or in beads of a porous material)
- alginate beads containing lactase & putting them into milk
- lactose concentration drops & glucose concentration rises
Advantages of lactose-free milk
- sweeter
- less crystallisation (more soluble)
- faster fermentation = yoghurt / cheese
What are pyrimidines?
- single ring nitrogenous bases
- cytosine
- thymine
- uracil
What are purines?
- double ring nitrogenous bases
- guanine
- adenine
How many nitrogenous bases per complete turn of DNA double helix?
10 pairs of bases per turn
Define semi-conservative
- the products of DNA replication each contain one of the ORIGINAL strands & one NEW strand
In which direction is the parent strand READ?
from 3’ to 5’ direction
In which direction is the daughter strand BUILT?
from 5’ to 3’ direction
- DNA polymerase adds the 5’ end of the incoming nucleotide to the 3’ end of the previously placed nucleotide
Where does transcription occur?
in the nucleus
Where does translation occur?
at a ribosome
Outline the genetic code
- rules used by all cells to translate info encoded within genetic material (DNA) into proteins
Define redundant in terms of genetic code
genetic code is redundant, meaning more than one codon may specify a particular amino acid (means DEGENERATE)
Benefits of using gene transfer technology to produce insulin
- biotechnologically produced insulin is indistinguishable from human insulin produced in pancreas
- large quantities of insulin produced
- ethical issues eliminated (e.g. can’t use pig insulin)
- this type of insulin is absorbed more rapidly
How many amino acids are in insulin?
51
Define cell respiration
the controlled release of energy from organic compounds to produce ATP
Uses of ATP in cell
- powers active transport
- synthesises polymers
- moves structures within the cell
ENERGY IS RELEASED WHEN PHOSPHATE GROUP IS REMOVED FROM ATP IN HYDROLYSIS REACTION
Compare the total amount of ATP made from anaerobic & aerobic respiration.
- net of 2 ATPs per molecule of glucose (ANAEROBIC)
- net of 38 ATPs per molecule of glucose (AEROBIC)
How is anaerobic respiration in yeast used to make ethanol drinks & biofuel?
- yeast can be used to produce ethanol by fermentation
- yeast is cultures in liquid containing sugar & other nutrients
- no oxygen, so respires anaerobically
- ethanol concentration of fluid around yeast cells rises to ~ 15% by vol
- fermentation ends, CO2 bubbles out into atm
- alcohols brewed
- also ethanol can be used for fuel
Which wavelengths of light does chlorophyll absorb?
red and blue
Define accessory pigments
Accessory pigments are light-absorbing compounds, found in photosynthetic organisms, that work in conjunction with chlorophyll a
e.g. chlorophyll b or carotenoids
Where does photolysis occur?
in thylakoids
Define limiting factor
- the variable of a system that can limit the rate of a reaction
e.g. light, temp. CO2
Explain how hydrophobic and hydrophilic properties contribute to the arrangement of molecules in a membrane (7)
a. hydrophilic is attracted to/soluble in water and hydrophobic not attracted/insoluble
b. hydrophilic phosphate/head and hydrophobic hydrocarbon/tail in phospholipids
c. phospholipid bilayer in water/in membranes
d. hydrophilic heads «of phospholipids» face outwards/are on surface
e. hydrophobic tails «of phospholipids» face inwards/are inside/are in core
f. cholesterol is «mainly» hydrophobic/amphipathic so is located among phospholipids/in hydrophobic region of membrane
g. some amino acids are hydrophilic and some are hydrophobic
h. hydrophobic «amino acids/regions of» proteins in phospholipid bilayer «core»
i. hydrophilic «amino acids/regions of» proteins are on the membrane surface
j. integral proteins are embedded in membranes due to hydrophobic properties/region
OR transmembrane proteins have a hydrophobic middle region and hydrophilic ends
k. peripheral proteins on are on the membrane surface/among phosphate heads due to being «entirely» hydrophilic OR «carbohydrate» part of glycoproteins is hydrophilic so is outside the membrane
l. pore of channel proteins is hydrophilic
What are phosphates used to make?
phospholipids/nucleotides/nucleic acids/DNA/RNA/ATP
What are nitrates used to make?
amino acids/proteins/nucleotides/nucleic acids/DNA/RNA/ATP
Outline the importance of water to living organisms
a. coolant in sweat/in transpiration;
b. water has a high heat of vaporisation / heat taken when hydrogen bonds break;
c. water is cohesive so can pulled up/so can be moved under tension in xylem;
d. water is an excellent/universal solvent/dissolves many different substances;
e. medium for transport in blood/xylem/phloem;
f. medium for metabolic reactions / (metabolic) reactions happen dissolved in water;
g. surface tension due to cohesion allows organisms to live on water surface;
h. water has high heat capacity so much energy required to change its temperature;
i. ice floats so lakes/oceans do not freeze allowing life under the ice;
j. high heat capacity so stable habitat/so temperature of water changes slowly;
k. used in chemical reactions/photosynthesis/hydrolysis in organisms;
To which end are nucleotides added in transcription?
added to 3’ end (5’ to 3’ direction)
Define condensation
joining together molecules with the release of water
State the role of four named minerals needed by living organisms.
sulfur – part of amino acids / proteins;
calcium – strengthening/formation of bones / muscle contraction / synaptic transmission;
phosphorus – formation of nucleic acids / ATP / GTP / NADP / phospholipids;
iron – formation of hemoglobin / transport of oxygen;
sodium – nerve impulse / sodium-potassium pump / osmoregulation;
potassium – nerve transmission / sodium-potassium pump / osmoregulation;
magnesium – part of chlorophyll molecule;
Distinguish b/w fibrous & globular proteins.
- fibrous proteins are strands/sheets whereas globular proteins are rounded;
- fibrous proteins (usually) insoluble whereas globular proteins (usually) soluble;
- globular more sensitive to changes in pH/temperature/salt than fibrous;
