Bio BME Flashcards
What are the two names bases are divided into and what bases go with these names
Bases are divided into purine and pyrimidine.
Purine: A and G
Pyrimidine: T C U
What is a nucleoside
Base and sugar with no phosphate group
How does polarity arise in DNA
Due to phosphodiester bond which offers directionality/polarity of the molecule.
What are chromatids made of
Made of solenoids which are composed of nucleosomes
What is a nucleosome
Part of the structure of chromosomes where DNA is wrapped around his tone proteins
Define transcription
And the steps
First step of gene expression we where DNA is copied into RNA
Consists of initiation, elongation and termination
what is the primary structure of the protein
AA are linked by peptide bonds and resultant polypeptide chain has an N terminus and C terminus which coincides with their amino and carboxyl ends
what is the secondary structure of a protein
carboxy and amino group are highly polar thus gives C-N bond a slight double bond character allowing H-bond=>linear polypeptide chain able to fold to certain structures ie alpha helix or beta pleated sheet
what is collagen
fibrous protein with triple helix (intertwined of 3 polypeptide chains)
what does haemoglobin have in terms of structure
2 alpha globin & 2 beta globin chain
explain quaternary structure
protein structure made of 2 more polypeptides chains forming oligomers *(few subunits)-> subunits can be same(homomers) or diff (heteromers)
what do lipoproteins do
carries dietary fats in blood
what is the function of albumin
one major protein carrier molecule in blood that bind to drugs, allergens etc
what is one of the function for collagen and fibrin
critical role in wound healing and hemostasis
Define mutation
Alteration in DNA sequence which can result form chemicals, irradiation, lack of repair of replication mistakes
What are viruses that infect bacteria called
Bacteriophages
What main process does viruses lack
Homeostasis-> capacity tor emulate and sustain internal environment
What is nucleocapsid in virus
Is the genome and the capsid together
What are oncoviruses
Viruses linked with the development of cancer-> produce proteins that inhibit or deteriorate the function of TSG which play key role in cell division
Inactive TSG= cell grow uncontrollably therefore tumour forms
How is HIV caused
Retrovirus that causes severe dampening of immunity by depleting T-lymphocytes=> opening sufferer to opportunistic infections
What is cancer (human papilloma virus)
Cervical cancer is induced by oncogenic proteins produced by special types of human papilloma virus
What is virion
The complete infective form of a virus outside a host cell with core of RNA and capsid
Define virulence
Degree of pathology caused by pathogen
What are the ways prokaryotes reproduce (4)
Binary fission
Transduction
Transformation
Conjugation
What is a capsule on a prokaryotic cell
Polysaccharide that aid prokaryotes such as bacteria to adhere to surfaces and to each other also prevent desiccation of microbe
What is appendages on prokaryotic cells
prokaryotic cells contain a few appendages which are protrusions on the cell surface such as fimbriae, pili and flagella.
What are fimbriae, pili and flagellum
- Fimbriae are thin filaments that aid adhesion.
- Pili are longer structures that play a role in conjugation and in some cases movement, whilst
- flagellum is a structure that helps the cell to move around.
what are peroxisome in the eukaryote cell
aids in metabolizing waste
define binary fission
process of asexual reproduction that bacteria uses to divide creating 2 identical daughter cells
define conjugation
direct contact used to transfer genetic material between bacteria
define transformation
exogenous DNA transferred into host
define transduction
process virus transfer genetic material between bacteria-> performed by bacteriophages
what is secondary active transport
example of coupled transport which utilized electrochemical potential difference established by the movement of ions for transport ie H pumps create electrochemical gradient which can be used via electron transport chain for cellular respiration in mitochondria
what is pinocytosis and what is it
cellular drinking
plasma membrane creates channel allowing dissolved substances to enter cell
what is phagocytosis
cellular eating
what is a pinosome
fluid filled vesicle within a cell
what is the enzyme oxidoreductases
and the 6 groups
what are the 6 groups
enzymes involved in oxidation and reduction
categorised into 6 main groups: oxidases(O as hydrogen or e- acceptor), dehydrogenase(oxidize substrates by transferring 1 or more hydride ions), oxygenase(incorporate O into organic substrate), hydroxylases(add hydroxyl group to substrate), hydro peroxidases(reduce of hydrogen peroxide and hydroperoxide) and reductases(catalyze reduction)
where does glycolysis occur
anaerobic reaction that occur in cytosol
what are the two types of metabolism and describe them
catabolism: breakdown of molecules ie glucose to pyruvate in glycolysis
anabolism: synthesis of compounds and molecules ie protein synthesis
define cytosol
intercellular fluid-liquid compartment of the cell
define muscular cramps
involuntary muscle contraction which causes significant pain and paralysis like immobility of the affected muscle usually due to lactic acid build up in muscle
what is the tumour suppressor protein in G2 phase in the cell cycle
p53
one of mainstays of cancer is mutation of p53= cause uncontrollable cell division
describe prometaphase
chromosomes led by their centromere align in centre of cell at right angle to centrosomes
spindle fibres bind to kinetochore, chromosome’s continue to condense
describe metaphase
chromosomes attach to metaphase plate of mitotic spindle
describe anaphase
centromere divide and sister chromatid are separated to opposite ends of cell by mitotic spindle pulling on kinetochore
what is metaphase plate
plane in equatorial region of spindle in dividing cells, along which chromosome’s become arranged during metaphase
what is a kinetochore
protein structure that forms on chromatid during cell division and allows to attach to spindle fibre on chromosome
what are the 4 steps in DNA replication in prokaryotes
initiation
unwinding
elongation
termination
describe initiation of DNA replication in prokaryotes
Initiation: The origin for DNA replication in E. coli is known as oriC, this genetic
locus contains the binding site for the initiator protein DnaA, single stranded binding
protein (5sb) holds the DNA bubble open allowing DnaB protein to bind! DnaB is a
helicase which uses ATP to melt double stranded DNA
describe unwinding of DNA replication in prokaryotes
Unwinding: After DNA helicase travels along the template strand and opens it for
copying, supercoiling is prevented by DNA gyrase (type Il topoisomerase). DNA Eyrase lessens supercoiling (relaxes tension) which builds up during DNA unwinding
preventing DNA breakage,
describe elongation in DNA replication in prokaryotes
Elongation: leading and lagging strand primers are elongated by the DNA polymerase
Ill holoenzyme, the subunit is a dimer, the leading and lagging strands are synthesized
simultaneously. The leading strand is made as a continuous piece (5-3 direction)
whilst the lagging strand is made in fragments (okazaki) in a 3-5 direction (see fig 1),
The looping of the lagging strands makes the process possible, DNA polymerase I fills
in the gaps once the primers are removed, DNA ligase makes the final phosphodiester
bond between the fragments.