BIOC0001 EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
Phase contrast microscopy
Allows to examine transparent/ living specimens without staining them.
Light microscopy (bring field)
Haemotoxylin (binds yo acidic molecules -DNA) and eosin stain (amino acids).
Confocal microscopy
Light microscope that uses fluorescent stains and laser to make two- and three-
dimensional images through thick cells.
Conventional fluorescent microscopy limitations
Cutting destroys material, fluorescent emitted light causes blurriness.
Electron microscopy
Causes breakage of chemical bonds and created free radical but coating specimens
with heavy metals can protect against this, but reduce the resolution.
Transmission electron microscope (TEM)
2D, image shown on fluorescent screen.
Cryo
Allows examination of hydrated, unfixed and unstained biological specimens. Samples
need to be frozen in liquid nitrogen/ ethene. Very low temperature keeps the =water
from evaporating in the vacuum.
Pyrimidines
TUC
,Purines (two rings)
GA
Generation fo new combinations of double sanded DNA sequences during gene
cloning
The generation of sticky ends following DNA restriction allows complementary DNA
sequences to hybridise. As long as the ends pieces of the DNA are complementary at
the restriction site, foreign DNA can be introduced.
DNA hybridization
Separation of the double stranded DNA can be achieved using heat and alkali
conditions. Reversing the conditions allows the DNA to re-anneal.
Palindromic sequences
Can be read both ways
Central dogma theory
DNA-transcription-RNA-translation-protein (genetic information can only flow this way)
Replisome
Complex of DNA polymerase and other enzymes that catalyzes the synthesis of DNA.
Prokaryotes DNA replication
Origin of replication OriC, one replicon.
Eukaryotes DNA replication
Multiple replicons: origins 3 & 5 initiate, followed by 1, 2 and 4 are passively replicated.
Replication initiation
, DNAa binds at oriC at DnaA boxes. DnaB helices unwinds DNA and SSB's (single
stranded DNA binding protein) keep strands from reannealing. DnaC- helices loader
transfers helices to replication origins.
DNA primase
Forms short RNA primer complementary to the unwound template strands. The primer,
still base-paired to its complementary DNA strands, is then elongated by DNA
polymerase, thereby forming new daughter cell.
Initiator protein
DnaA, recognizes DNA and binds.
Tropoisomerase type 1
Relax DNA by nicking and closing one strand of duplex DNA. (negative supercoils)
Tropoisomerase type 2
Change DNA topology by breaking and rejoining ds DNA. (overwound region, positive
supercoils) Decatenation.
DNA polymerase I
Encodes for polyA gene, fills the gaps, repairs, bidirectional, removes RNA primer form
5 to 3, only acts on lagging strand.
RNA polymerase II
mRNA
RNA polymerase III
tRNA transcription
DNA replication is accurate due to...
COMPLETE SOLUTIONS VERIFIED
Phase contrast microscopy
Allows to examine transparent/ living specimens without staining them.
Light microscopy (bring field)
Haemotoxylin (binds yo acidic molecules -DNA) and eosin stain (amino acids).
Confocal microscopy
Light microscope that uses fluorescent stains and laser to make two- and three-
dimensional images through thick cells.
Conventional fluorescent microscopy limitations
Cutting destroys material, fluorescent emitted light causes blurriness.
Electron microscopy
Causes breakage of chemical bonds and created free radical but coating specimens
with heavy metals can protect against this, but reduce the resolution.
Transmission electron microscope (TEM)
2D, image shown on fluorescent screen.
Cryo
Allows examination of hydrated, unfixed and unstained biological specimens. Samples
need to be frozen in liquid nitrogen/ ethene. Very low temperature keeps the =water
from evaporating in the vacuum.
Pyrimidines
TUC
,Purines (two rings)
GA
Generation fo new combinations of double sanded DNA sequences during gene
cloning
The generation of sticky ends following DNA restriction allows complementary DNA
sequences to hybridise. As long as the ends pieces of the DNA are complementary at
the restriction site, foreign DNA can be introduced.
DNA hybridization
Separation of the double stranded DNA can be achieved using heat and alkali
conditions. Reversing the conditions allows the DNA to re-anneal.
Palindromic sequences
Can be read both ways
Central dogma theory
DNA-transcription-RNA-translation-protein (genetic information can only flow this way)
Replisome
Complex of DNA polymerase and other enzymes that catalyzes the synthesis of DNA.
Prokaryotes DNA replication
Origin of replication OriC, one replicon.
Eukaryotes DNA replication
Multiple replicons: origins 3 & 5 initiate, followed by 1, 2 and 4 are passively replicated.
Replication initiation
, DNAa binds at oriC at DnaA boxes. DnaB helices unwinds DNA and SSB's (single
stranded DNA binding protein) keep strands from reannealing. DnaC- helices loader
transfers helices to replication origins.
DNA primase
Forms short RNA primer complementary to the unwound template strands. The primer,
still base-paired to its complementary DNA strands, is then elongated by DNA
polymerase, thereby forming new daughter cell.
Initiator protein
DnaA, recognizes DNA and binds.
Tropoisomerase type 1
Relax DNA by nicking and closing one strand of duplex DNA. (negative supercoils)
Tropoisomerase type 2
Change DNA topology by breaking and rejoining ds DNA. (overwound region, positive
supercoils) Decatenation.
DNA polymerase I
Encodes for polyA gene, fills the gaps, repairs, bidirectional, removes RNA primer form
5 to 3, only acts on lagging strand.
RNA polymerase II
mRNA
RNA polymerase III
tRNA transcription
DNA replication is accurate due to...
