Unit 1 - DNA & The Genome Flashcards
what is the subunit of DNA
nucleotide
What sugar is found in a DNA nucleotide
deoxyribose
To which carbon (number) is the base attached
1
To which carbon (number) is the phosphate attached
5
To which carbon (number) is the phosphate on the next nucleotide attached
3
name the structure DNA forms
double stranded, double helix
what describes the strands in DNA
anti-parallel
name all 4 bases in DNA
Adenine, Thymine, Guanine, Cytosine
Give the complementary base pairing in DNA
A to T and G to C
what type of bond connects complementary base pairs
Hydrogen
what type of bond connects sugars to phosphates in DNA
(strong) covalent
The repeating sugar - phosphate structure is called the..
backbone
what cell type contains a membrane bound nucleus
eukaryote
what cell type lacks a nucleus
prokaryote
what DNA structures does a prokaryote contain
single circular chromosome and plasmids
what organelles contain DNA
nucleus, chloroplast, mitochondria
what form are the chromosomes in, in eukaryotic cells
linear
what form do the chromosomes take in chloroplast and mitochondria
circular
Name the proteins which eukaryotic chromsomes are associated with
histones
what is the charge on DNA strands
negative
what is the charge on histones
positive
why is yeast considered a ‘special’ form of eukaryote
it contains plasmids
what enzyme extends the strand in DNA replication
DNA polymerase
what enzyme joins together fragments on the lagging strand
ligase
what end of the DNA can DNA polymerase synthesise in a continuous strand
Adds to the 3’ end / Reads from 5’
what are the 2 strands called during DNA replication
leading and lagging
what is required to bind to the DNA strand for DNA polymerase to bind
primers
what are the primers made of in DNA replication
RNA
what enzyme untwists and ‘unzips’ the DNA during replication
helicase
List the 5 requirements for DNA replication
ATP, free DNA nucleotides, enzymes (helicase, ligase and DNA polymerase), Parental/Template DNA strand, primers
what is the name for the form of replication used by DNA
semi-conservative (replication)
what is the name of the structure formed where helicase breaks the bases
replication fork
what bonds break during DNA replication
Hydrogen bonds (between the complementary base pairs)
what does PCR stand for
Polymerase Chain Reaction
what is the purpose of PCR
to amplify a specific sequence of DNA
what is the purpose of primers in PCR
to bracket the required sequence
what is unusual about the DNA polymerase used in PCR
it is heat tolerant
what temperature does DNA denature at in PCR
92-98oC
what happens at 92-98oC
DNA denatures/DNA strands separate
what temperature do primers anneal at in PCR
50-65oC
what happens at 50-65oC in PCR
primers anneal
what temperature is the DNA strand extended at in PCR
70-80oC
what happens at 70-80oC in PCR
DNA strand is extended
what techinique can be used to separate different sizes of DNA fragment
gel electrophoresis
name 3 things that PCR can be used for
forensic investigations, paternity suits, testing for genetic disorders, (Covid-19 testing)
what 2 processes are involved in gene expression
transcription and translation
the pattern of gene expression determines what in an individual
phenotype
as well as genotype, what else impacts on an individuals phenotype
environmental factors
modifications to DNA which do not change the sequence are what type of change
epigenetic
all of the alleles present defines the …
genotype
different forms of gene are called
alleles
a signal from inside the cell that alteres gene expression is called
intracellular
a signal from outside the cell that alters gene expression is called
extracellular
name the 3 main forms of RNA used in gene expression
tRNA, mRNA, rRNA
where do you find rRNA
ribosome
which form of RNA is found in the nucleus and the cytoplasm
mRNA
what is the sugar found in RNA
ribose
What difference in bases is there between DNA and RNA
thymine is replaced with Uracil
how many strands do you find in DNA and RNA
2 in DNA, 1 in RNA
what enzyme creates the primary transcript in transcription
RNA polymerase
what functions (4) does RNA polymerase carry out
Untwists and Unzips gene, pairs up nucleotides and forms backbone
what is name for a triplet of bases on DNA/mRNA
codon
what is the name for the triplet of bases found on tRNA
anti-codon
what 2 main structural sites are needed on a tRNA molecule
anticodon and amino acid attachment site
what is the name of the sequence RNA polymerase binds to to start transcription
promotor
what process alters a primary transcript to a mature transcript
splicing
what process allows one gene to code for several proteins
alternative splicing
what sequences are removed during splicing
introns
what sequences are kept during splicing
exons
what is important about the sequence of exons during splicing
the sequence does not change
where does translation take place
ribosome
what codon types are required during translation (3)
start, coding, stop
what bond is formed between amino acids during translation
peptide
give an example of an interaction that helps form the 3D structure of a protein
hydrogen bonds, covalent bonds (link across chains), ionic bonds, hydrophobic interactions, Van der Waals (includes H Bonding)
give two properties of a stem cell
unspecialised, can self-renew
what is the term for a cell changing from unspecialised to specialised
differentiation
what is the name for unspecialised cells in plants
meristems
what term describes embryonic stem cells
pluripotent
what term describes cells which can form all cell types in the organism
pluripotent
what term describes cells which can form a subset of cell types
multipotent
what terms describes tissue stem cells
multipotent
what are tissue stem cells used for in the body (generally)
growth and repair
name a therapeutic use of stem cell
e.g. bone maroow transplants, corneal grafts, skin grafts….
name a research use of stem cells as model cells
e.g. new drug testing, cell growth, cell differentiation, gene expression…
stem cell research involves the destruction of early embryos. What term is used to describe the issues raised from this
ethical
what contains more sequence in the genome; coding or non-coding DNA
non-coding
all of the genetic material that can be passed on to offspring is called the…
genome
give examples of sequences which are transcribed but not translated
e.g. tRNA, rRNA, introns
give and example of why non-coding sequences needed on the genome
e.g. to regulate transcription, bind proteins, fold DNA….
a sequence of bases which codes for a protein is called a..
gene
A random change in DNA is called a..
mutation
name the 3 single gene mutations
substitution, insertion, deletion
what is meant by ‘point mutation’
a single base change
what mutations cause a frame shift
insertion and deletion
a mutation that creates a stop codon is called a..
nonsense mutation
a mutation that changes the amino acid coded for is called a ..
missense mutation
a mutation that does not change the amino acid coded for is called a ..
silent mutation
a mutation that can result in introns remaining in coding is called a
splice-site mutation
a mutation that can result in exons being removed from code is a..
splice-site mutation
name the 4 chromosome mutations
deletion, inversion, translocation, duplication
A section of chromosome added from a homologous chromosomes whould cause which type of mutation
duplication
A section of chromosome removed would cause which type of mutation
deletion
A section of chromosome flipped over cause which type of mutation
inversion
a section of chromosome moved to a non-homologous chromosome is called
translocation
duplication allows change in a gene which still retaining original function, what process is this important for
evolution
the passing of genetic information from parent to offspring is called
vertical gene transfer
the passing of genetic information between individuals in the same generation is called
horizontal gene transfer
what type of organism regularly use horizontal gene transfer
prokaryotes
the non-random increase in the frequency of alleles that favour survival is called
natural selection
phenotypes which increase the likelyhood of survival are said to have a ..
selective advantage
give 3 examples of things which can apply a selction pressure
e.g. predators, grazers, disease, climate conditions…
what are the 3 forms of selection
stabilising selection, directional selection, disruptive selection
what will happen to the mean and range in stabilising selection
mean remains the same, range is decreased
what will happen to the mean and range in directional selection
the mean will shift and the range will remain the same around the mean (also shifted on axis)
what will happen to the mean and range in disruptive selection
the range will be split into 2 and 2 distinct means start to develop
give two reasons why evolution is faster in prokaryotes
horizontal gene transfer and short generation time
what is the sequence of events in speciation (4)
isolation of gene pools, mutation/variation, natural selection with different selective pressures, many generations
what is used as a test for stating speciation has occurred
when individuals from one population can no longer produce fertile offspring with the other
if an extreme phenotype is selected for, what form of selection occurs
directional
if the extremes of phenotype are selected against, what form of selection occurs
stabilising
if the two extremes of phenotype are selected for, what form of selection occurs
disruptive
what is the source of novel alleles in a population
mutation
what are the 3 forms of isolation barrier in speciation
geographical, behavioural, ecological
give an example of a geographical isolation barrier
e.g. sea, mountain, canyons….
give an example of an ecological isolation barrier
e.g. pH, temperature, habitat choice..
give an example of a behavioural isolation barrier
e.g. reproductive cycles out of sync, active times out of sync…
where subpopulations are isolated by geographical barrier the form of speciation is called..
allopatric
what form of isolation barrier causes allopatric speciation
geographical
where subpopulations are in the same geographical location what form of speciation can occur
sympatric
what form of isolation barrier causes sympatric speciation
ecological and behavioural
the use of comparisons of sequence data and statistical analysis is called..
bioinformatics
the branch point in a phylogentic tree shows a
common ancestor
phylogenetic trees normally have a scale in..
mya / millions of years ago
as well as sequence data, what other evidence is used to track evolution
fossil record
what can you conclude if there is a high level of conserved sequence between two species
that they are closely related
what are the three domains of life
eukaryotes, prokaryotes, archae
what is the universal common ancestor
the cell that all life on earth can be tracked back to
what is a molecular clock
a gene/protein sequence which has a known mutation rate, so divergence can be used to work out time
using genetic information to determine choice or dosage of drug is called
pharmacogenetics
give an ethical issue linked to personal genomics
e.g. genetic risk could be used by companies for job/access/insurance. Who ‘owns’ the sequence/information?
