Topic 2 Flashcards
Distinguish between unique and highly repetitive DNA sequences [6]
- HR makes up a larger proportion of the total genome than unique
- unique are much shorter sequences than HR
- unique are translated into proteins, HR aren’t
- unique don’t vary much between individuals, HR vary highly
- unique occur once in a genome, HR occur many times
- unique may be genes, HR are not genes
- repetitive DNA is used for profiling
- satellite DNA is formed from repetitive sequences
- prokaryotes usually don’t have repetitive sequences
Outline the outcomes of the human genome project [6]
- promote international cooperation
- provide evidence for evolutionary relationships
- improve ability to SCREEN FOR certain diseases/ find genes causing certain diseases
- tailor medication to individual genetic variation
- development of new gene therapies
- find the functions/structures of certain proteins
- all the human genes/their positions mapped
- complete human DNA SEQUENCED
- find mutations
Why C is an important compound
- forms 4 covalent bonds
- can form large variety of complex, stable molecules
What is an organic molecule
Contains carbon and is found in living org.
(exceptions - CO3(2-), CN-, CO, CO2, CaC2)
Functions of different organic molecules
Carbohydrates:
- most abundant org molecule -> CHO
- used as short term energy storage + energy source
- can be a recognition molecule (glycoproteins) or a structural component (sugar-phosphate backbone in DNA/RNA)
Proteins:
- made up of CHON(S)
- important role in catalysis of reactions (as enzymes)
- structural, cell recognition and transport functions
Nuc acids:
- make up genetic material of all cells
- DNA -> instructions for protein synth. RNA -> has many roles in protein synth
- CHOPN
Lipids:
- non-polar molecules used in membranes
- also used as a signalling molecule -> steroids
- used as long-term energy storage -> fats and oils
Monomers of different types of compounds
Carb:
- monosaccharides
Protein:
- Amino acids
Nucleic acids:
- nucleotides
Lipids:
- no monomers as such, as lipids have various different structures
- have smaller subunits -> fatty acid chains, monoglycerides
Types of lipids
simple: esters of fatty acids and alcohol
compound: esters of fatty acids, alcohols and additional groups
derived: substances derived from simple and compound lipids -> steroids/carotenoids, etc
Vitalism + disproving
vitalism: doctrine that living beings contained a vital force needed to synthesise organic molecules. Frederick Woehler showed that organic molecules were not fundamentally different from inorganic molecules
- Heated inorganic salt ammonium cyanate
- produced urea -> waste product of metabolism in many living org
Functions of metabolism
- source of energy for growth processes (reproduction, cell growth)
- synthesis and assimilation of new materials for use in cells
Anabolic v. Catabolic
A: the buildup of complex polymers from simple monomers. Often condensation reactions that are endergonic.
C: The breakdown of complex polymers into simple monomers. Often hydrolysis reactions that are exergonic
Properties of water that make it good for living organisms
- High LHV: Makes it good coolant in sweat
- High SHC: Maintenance of constant environment (internal and external)
- Surface tension bc of cohesion: organisms can walk on water
- Adhesion/cohesion: transpiration stream
- Universal solvent: component of blood, plant sap
- Expands upon freezing -> ice caps float on water -> provide a habitat
Substances that travel in blood
- Ions
- O2 (only low quantities can dissolve) mainly travels in RBC
- glucose - it has many OH groups hence can dissolve
- AAs -> either the amine or carboxyl group will be charged
Substances that don’t freely travel in blood
- Lipids: since they are large and NP
-> form lipoprotein complexes -> the hydrophilic parts of proteins, chol. and phospholipids face outwards -> hypho parts are shielded
Functions of mono, di and polysaccharides
- Mono: immediate source of energy
- Di: usually used as a transport form
- Poly: for long term energy storage
Types of sugar polysaccharides
Starch(plants):
- Amylose: alpha glucose, helical molecule, 1-4 glycosidic linkages, used to store energy -> takes up less space in plants. Harder to digest though
- Amylopectin: alpha glucose, branching structure, 1-4 and 1-6 glycosidic linkages -> branching allows for easier retrieval of glucose
Glycogen(animals):
- alpha glucose, branching (more extensive than amylopectin)
- 1,4 and 1,6 glycosidic linkages
- energy storage in animals
Cellulose:
- beta glucose, every other glucose monomer is flipped
- creates a straight chain molecule with 1-4 glycosidic linkages
- cellulose forms myofibrils
- high tensile strength to allow turgidity
Triglyceride formation
- most common form of lipids
- glycerol (CH2OHCHOHCH2OH) reacts with 3 fatty acids in a condensation reaction -> 3 ester linkages between the OHs of the glycerol and COOH of the fatty acids
LDLs and HDLs
- high density lipoproteins are good for the body -> they carry cholesterol to the liver for removal
- LDLs are bad -> they carry cholesterol from the liver to rest of body
- cis unsaturated fats increase HDLs
- saturated fats increase LDLs
- trans fats increase LDLs and decrease HDLs
Sugars v lipids to store energy
- Lipids store twice as much energy per gram than sugars
- sugars are easier to metabolise
- sugars are easier to transport in the bloodstream
- lipids are insoluble in water, hence don’t impact osmolarity
- lipids more suitable for longterm storage
calculating BMI
mass in kg/(height in m)^2
What is quaternary protein structure
more than one polypeptide chain linked together, or if proteins have inorganic prosthetic groups in the structure
eg:- haemoglobin - has 4 polypeptide chains + haeme groups
secondary structure
formed when the amino acid sequence folds into 2 stable structures
- alpha helices
- beta pleated sheets
if no 2 structure -> just forms a random coil
Effect of temperature on proteins
- if temperature too high, H bonds holding the structure together break
- the 3D structure of the protein is altered as it unfolds -> cannot effectively carry out its function
Effect of pH on proteins
- AAs are zwitterions -> neutral but contain positively and negatively charged regions
- when pH changes charge on the AA changes
- may become insoluble and change shape
Proteome
totality of the proteins expressed in a cell, tissue or organism at a given time
varies amongst individuals -> larger than the genome bc of alternative splicing + protein modification
