Unit 1: DNA and the genome Flashcards
what does the nucleus store?
genetic information
where are chromosomes found?
nucleus
what packages the genetic information?
chromosomes
what are chromosomes made of?
DNA
what is the shape of DNA?
two strands which form a twisted structure (double helix)
what is each strand of DNA made up of?
nucleotides
what are the three parts of a nucleotide?
phosphate, deoxyribose sugar, base
what are nucleotides in a chain joined together by?
sugar-phosphate bonds
what is the name for a chain of nucleotides?
polynucleotides
what type of backbone does dna have?
sugar-phosphate backbone
where do the nucleotides bond at?
3’ and 5’
how is 3’ pronounced?
three prime
what base pairs with thymine?
adenine
what base pairs with guanine?
cytostine
what base pairs with adenine?
thymine
what base pairs with cytosine?
guanine
what joins the base pairs?
hydrogen bonds
what is the shape of the double helix called?
anti-parallel
what does anti-parallel mean in dna?
the nucleotides on one side goes from 5’ to 3’ and the other 3’ to 5’
describe a prokaryotic cell
- dna is not housed within nuclear envelope
- dna is stored in single circular chromosome
- small circular SNA is called plasmid
give an example of a prokaryotic cell
bacteria cell
describe how dna is stored in prokaryotic cells?
dna is not housed within nuclear envelope, it is stored in a single circular chromosome
where is dna not stored in a prokaryotic cell?
the nucleus
where is dna stored in a prokaryotic cell?
in small circular dna (called plasmids)
what is a plasmid
small circular dna
what is the purpose of dna supercoiling?
to package dna to fit inside a cell
describe the relationship of dna in and histones in eukaryotes
each nucleosome consists of clusters of 8 histone proteins , the dna is weapped around it
describe the storage of dna in eukaryotic cells
dna is housed within a nuclear envelope, linear dna is packaged with proteins
where are circular chromosomes also found?
mitochondria and chloroplasts
What is the DNA parental strand composed of?
2 complementary strands
What is step 1 of dna replication?
Hydrogen bonds between the bases break - separating the strands
What is step 2 of dna replication?
Free nucleotides start to line up with complementary nucleotides
What is step 3 of dna replication?
The sugar phosphate bonds form. Two dna molecules identical to the parental molecule have been formed
What are the 3 steps of dna replication?
- Hydrogen bonds between the bases break - separating the strands
- Free nucleotides start to line up with complementary nucleotides
- The sugar phosphate bonds form. Two dna molecules identical to the parental molecule have been formed
What does the enzyme DNA polymerase control?
Controls the formation of the sugar-phosphate bonds when making the new strand
What enzyme controls the formation of the sugar phosphate bonds when making the new strand?
DNA polymerase
What does dna polymerase do?
Adds dna nucleotides using complementary base pairings to the 3’ end of the new dna strand
What does dna polymerase need to start replication?
Primers
What is a primer?
A short strand of nucleotides which binds the 3’ end of the template DNA strand allowing polymerase to add DNA nucleotides
What is PCR?
DNA replication in a lab setting
What is the full name of PCR?
polymerase chain reaction
Another name for dna replication
DNA amplification
Why is dna replication sometimes called dna amplification?
Because PCR allows specific sections of dna to be amplified in vitro
What is the meaning of in vitro?
In glass
First stage of PCR?
- DNA is heated at 92-98 degrees Celsius for a few seconds. This causes the dna to separate
What temperature is dna heated to in stage 1 of PCR?
92-98 C
What stage of PCR heats dna to 92-98 C?
Stage 1
What is stage 2 of PCR?
- Dna is cooled to 50 - 65 C. This allows short primers to bind to target sequence
What temperature is dna heated to in stage 2 of PCR?
50 - 65 C
What stage of PCR heats dna to 50 - 65 C?
Stage 2
What is stage 3 of PCR?
DNA is heated to 70 - 80 C. This allows a heat tolerant DNA polymerase to replicate the dna.
What temperature is dna heated to in stage 3 of PCR?
70 - 80 C
What stage of PCR heats dna to 70 - 80 C?
Stage 3
What is the number of double stranded copies of dna after 0 PCR cycles?
1
What is the number of double stranded copies of original DNA after 1 cycle?
2
What is the number of double stranded copies of original DNA after 1 cycle?
2
What is the number of double stranded copies of orignal DNA after 0 PCR cycles?
1
What is the number of double stranded copies of orignal DNA after 1 PCR cycles?
2
What is the number of double stranded copies of orignal DNA after 2 PCR cycles?
4
Three requirements for PCR
- Primers
- Supply of nucleotides
- Heat tolerant DNA polymerase
Description of an example of PCR
Genetic Disorder Diagnosis - DNA sequences that are known to indicate certain genetic disorders or diseases are amplified using PCR for diagnosis.
Why does DNA supercoil
So that dna fits inside a cell
DNA in eukaryotes
- chromosomes tightly coiled and packaged within histones
What cells have chromosomes tightly coiled and packaged within histones
Eukaryotes
Properties of a eukaryotic cell
- dna is housed within a nuclear envelope
- linear DNA is packaged with proteins
- circular chromosomes are also found in mitochondria and chloroplasts
Why is yeast a special example of a eukaryotes
It also has plasmids
Special example of a eukaryote
Yeast
DNA replication on the leading strand
- dna is unwound and hydrogen bonds between bases break to form two template strands
- a DNA primer binds to the 3’ end of the template DNA being copied
- DNA polymerase can add free nucleotides in one direction
this is a CONTINUOUS PROCESS until the LEADING STRAND is copied
DNA polymerase can only be added to ___ the end of the new strand
3’
Describe how DNA rectification takes place on the 5’ to 3’ strand (lagging strand)
- many primers attach along the strand
- these are extended by the DNA polymerase
- these fragments are then joined by the enzyme ligase
this is a discontinuous process
requirements for DNA replication
- DNA (to act as template)
- primers
- a supply of the 4 types of nucleotide
- DNA polymerase
- ligase enzymes
- a supply of ATP (energy)
function of ligase
enzyme which joins fragments together
function of unwinding and breaking bonds between bases
template DNA strand does this in preparation for replication
function of primer
starting point for DNA synthesis
function of semi-conservative strands wind up
2 genetically identical strands are synthesised
function of DNA polymerase
enzyme that adds nucleotides to new strand
How is dna packaged in prokaryotes
Circular chromosomes
Always have plasmids
Circular chromosomes
Always have plasmids
How dna is packaged in prokaryotes
How is dna packaged in eukaryotes
Linear chromosomes with histones
Always have plasmids
Full names of all bases
Cytosine
Guanine
Thymine
Adenine
Linear chromosomes with histones
Always have plasmids
How is dna packaged in eukaryotes
Gene expression
The transcription and translation of DNA sequences
The transcription and translation of DNA sequences
Gene expression
What is
DNA —-> RNA
transcription
transcription
DNA —-> RNA
What is
RNA —> AMINO ACID CHAIN
translation
Translation
RNA —> AMINO ACID CHAIN
mRNA
Carries a copy of DNA code from nucleus to the ribosome
Carries a copy of DNA code from nucleus to the ribosome
mRNA
what does mRNA carry from the nucleus to the ribosome
a copy of the DNA code
where does mRNA carry a copy of the DNA code to and from?
From the nucleus to the ribosome
tRNA
folds due to complementary base pairings
Each tRNA carries it’s specific amino acid to the ribosome
folds due to complementary base pairings
Each tRNA carriers it’s specific amino acid to the ribosome
tRNA
folding
AMINO ACID —> PROTEIN
What is …
AMINO ACID —> PROTEIN
Folding
Why does tRNA fold
Complementary base pairings
what does complementary base pairings cause tRNA to do
fold
what does each tRNA carry
It’s specific amino acid
where does tRNA carry it’s specific amino acid to
The ribosome
rRNA
proteins form in the ribosome with rRNA
What is phenotype determined by
Proteins produced as a result of Gene expression
what does Proteins produced as a result of gene expression determine
Phenotype
What does gene expression involve
- Transcription of DNA sequences
- Translation of DNA sequences
what involves
- Transcription of DNA sequences
- Translation of DNA sequences
Gene expression
only a _____ of the genes in a cell are expressed
Fraction
only a fraction of the genes in a cell are ________
Expressed
What do amino acids build up to
Protein molecule
What do three bases carry the code for
One amino acid
What carries the code for one amino acid
Three bases
What makes each amino acid different
The combination and sequence of bases
DNA nucleotide
Phosphate deoxyribose sugar base
Phosphate deoxyribose sugar base
DNA nucleotides
RNA nucleotide
Phosphate ribose sugar base
Phosphate ribose sugar base
RNA nulceotide
Similarities of DNA and RNA nucleotides
- Phosphate
- Base
- Phosphate
- Base
Similarities of DNA and RNA nucleotides
difference of DNA and RNA nucleotides
DNA has deoxyribose sugar
RNA has ribose sugar
DNA has Thymine
RNA has uracil
DNA has deoxyribose sugar
RNA has ribose sugar
DNA has Thymine
RNA has uracil
Difference of DNA and RNA nucleotides
in RNA, what replaces thymine?
Uracil
What does uracil pair with
Adenine
DNA overview
Double stranded
Has thymine
No uracil
Double stranded
Has thymine
No uracil
DNA overview
RNA overview
Single stranded
No thymine
Has uracil
Single stranded
No thymine
Has uracil
RNA overview
Gene
A section of DNA which carries the code for the production of a protein
A section of DNA which carries the code for the production of a protein
Gene
Protein synthesis
When the instructions on DNA sequences are carried to ribosomes where they are translated into proteins
When the instructions on DNA sequences are carried to ribosomes where they are translated into proteins
Protein synthesis
where is mRNA transcribed
the nucleus
what is transcribed in the nucleus
mRNA
Codon
Three DNA bases on mRNA
Three bases on mRNA
Codon
What is mRNA transcribed from
DNA sequences
What is mRNA translated into
Proteins
Where does mRNA get translated
The cytoplasm
what is translated in the cytoplasm
the mRNA
what translates mRNA
ribosomes
where is the mRNA molecule produced
Nucleus
How does mRNA leave the nucleus
Through a pore in the nuclear membrane
what leaves the nucleus Through a pore in the nuclear membrane
mRNA
where does mRNA go after leaving the nucleus
Cytoplasm
RNA polymerase
enzyme responsible for the transcription of DNA
enzyme responsible for the transcription of DNA
RNA polymerase
What does RNA polymerase do
- Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
- RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
- Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
- RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
What does RNA polymerase do
First thing RNA polymerase does
- Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
Second thing RNA polymerase does
- RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
- RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
Second thing RNA polymerase does
- Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
First thing DNA polymerase does
What does RNA polymerase produce
mRNA transcript
RNA polymerase adds nucleotides onto the ____ end of the _____ _____ _____
3’
Growing mRNA molecule
What means that the mRNA produced will be complementary to the DNA
base pairing rules
what is mRNA because of base pairings rules
Complementary to DNA
intron
Non coding region of a gene
Non coding region of a gene
Intron
Exon
Coding region of a gene
Coding region of a gene
Exon
Exons are ______
Expressed
Transcription
DNA > PRIMARY TRANSCRIPT
DNA > PRIMARY TRANSCRIPT
transcription
What are introns removed from
The primary transcript
What are removed from the primary transcript
Introns
In the formation of the mature transcript, exons are …
Sliced together
What is spliced together in the formation of the mature transcript
Exons
What is produced when exons are spliced together
Mature transcript
Where is the mature transcript produced
Nucleus
Where does the mature transcript go after production
Cytoplasm
After mRNA has been transcribed, what is removed
Introns
When are introns removed
After mRNA has been transcribed
The order of exons is _______ during slicing
Unchanged
Where is transfer RNA found
The cytoplasm
Why do tRNA fold
Complementary base pairings
what does tRNA have
- Anti codon site
- Amino acid site
- Anti codon site
- Amino acid site
tRNA
What does each tRNA molecule carry
It’s specific amino acid
Where does each tRNA carry its amino acid to and from
From the cytoplasm to the ribosome
where are anti codon found
tRNA
ribosomes
small almost spherical structures found in all cells
small almost spherical structures found in all cells
ribosomes
what form the ribosome
rRNA and proteins
what do rRNA and proteins form
ribosome
where are ribosomes found
some are free in the cytoplasm
others attached to the endoplasmic reticulum
what are found in…..
some are free in the cytoplasm
others attached to the endoplasmic reticulum
ribosomes
what are ribosome the site of
translation of mRNA into protein
where does translation of mRNA into protein happen
ribosomes in the cytoplasm
where does translation begin
at the start codon
what begins at the start codon
translation
what ends at the stop codon
translation
where does translation end
the stop codon
what do anti codons bond to
codons
how do anticodons bond to codons
buy complementary base pairings
what happen when anticodons bond to codons
translates the genetic code into a sequence of amino acids
translates the genetic code into a sequence of amino acids
what happens when anticodons bond to codons
what does the anticodons bonding to the codons form
peptide bonds
when do peptide bonds form
when anticodons bond to codons
what joins amino acids together
peptide bonds
what do peptide bond join together
amino acids
what does tRNA do when peptide bonds form
tRNA leaves the ribosome
when does protein synthesis end
at the stop codon
_________ proteins can be expressed from one gene, because of ___________
different
alternative splicing
different proteins can be __________ from __________, because of alternative splicing
expressed from one gene
different ___________ are produced from the same ____________ depending on which ________________
different mature mRNA transcripts are produced from the same primary strand depending on which exon are retained
cellular differentiation
the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell
the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell
cellular differentiation
what does cellular differentiation allow a cell do to
to carry out specialised functions
what allows cells to carry out specialised functions
cellular differentiation
what does every cell in a body have?
all genes
what cells have all genes
every cell
what can a cell do to its genes
switch them on or off when they are required
why do cells turn genes on and off
to not waste energy
example of selective gene expression
insulin produced in pancreas cells, not in heart or brain cells
insulin produced in pancreas cells, not in heart or brain cells
example of selective gene expression
in multicellular plants, where is growth restricted to
regions called meristems
in what is growth restricted to meristems
multicellular plants
meristems
regions of unspecialised cells in plants that can divide and/or differentiate
regions of unspecialised cells in plants that can divide and/or differentiate
meristems
each cell type has a …
different and specific
- structure
- shape
- size
- function
different and specific
- structure
- shape
- size
- function
each cell has a
stem cells
unspecialised cells in an animal that can….
- divide and self renew through cell division
- differentiate into specialised cells
unspecialised cells in an animal that can….
- divide and self renew through cell division
- differentiate into specialised cells
stem cells
sources of stem cells
- embryonic
- tissue
- embryonic
- tissue
sources of stem cells
embryonic stem cells extraction
zygote > blastocyst > stem cells
zygote > blastocyst > stem cells
embryonic stem cells
tissue stem cells extraction
bone marrow > bone marrow w lots of dif cells > bone marrow w stem cells > muscle cells, neural cells, etc
bone marrow > bone marrow w lots of dif cells > bone marrow w stem cells > muscle cells, neural cells, etc
tissue stem cells extraction
embryonic stems cells can _________ into ____ cell types in an organism
differentiate, all
pluripotent
cell can differentiate into all cell types in an organism
cell can differentiate into all cell types in an organism
pluripotent
what can embryonic cells do with genes
switch them all on and off
when do embryonic cells occur
in 5 - 7 day old embryos
what stem cells can switch all genes on and off
embryonic cells
tissue stem cells can differentiate into _______________ in a ________
all types of cell found in a particular tissue type
tissue stem cells can differentiate into all types of cell found in a particular tissue type
multipotent
multipotent
tissue stem cells can differentiate into all types of cell found in a particular tissue type
what are tissue stem cells involved in
the growth, repair, and renewal of the cells found in that tissue
what stem cells are involved in the growth, repair, and renewal of the cells found in that tissue
tissue stem cells
where are tissue stem cells found
bone marrow, muscle, and brain tissue in the body
what stem cells are found in bone marrow, muscle, and brain tissue in the body
tissue stem cells
corneal repair
- corneal limbus stem cells grown in a lab
- corneal stem cells trasplanted onto diseased cornea
- corneal limbus stem cells grown in a lab
- corneal stem cells trasplanted onto diseased cornea
corneal repair
first step corneal repair
- corneal limbus stem cells grown in a lab
- corneal limbus stem cells grown in a lab
first step corneal repair
second step corneal repair
- corneal stem cells trasplanted onto diseased cornea
- corneal stem cells trasplanted onto diseased cornea
second step corneal repair
what does stem cell research provide info on
how cell processes such as cell growth, differentiation, and gene regulation occur
how cell processes such as cell growth, differentiation, and gene regulation occur
what does stem cell research provide info on
what can stem cells be used for
used as model cells to study how diseases develop for drug testing
used as model cells to study how diseases develop for drug testing
what stem cells can be used for
why are there ethical issues in stem cells
the destruction of embryos
the destruction of embryos
ethical issues in stem cells
Genome
The entire hereditary information encoded in the DNA of an organism
The entire hereditary information encoded in the DNA of an organism
Genome
Humans have _________ base pairs of DNA
Humans have 3 billion base pairs of DNA
Humans have 3 billion ______________
Humans have 3 billion base pairs of DNA
What do base pairs contain
- Protein coding genes
- Non protein coding genes
- Protein coding genes
- Non protein coding genes
Base pairs of DNA
Most of the eukaryotic genome consists of ____________
Most of the eukaryotic genome consists of non coding genes
What % do coding regions make up of DNA
2%
many non protein coding regions are _____________
many non protein coding regions are made of DNA sequences which are repeated over and over
________________ DNA sequences which are repeated over and over
many non protein coding regions are made of DNA sequences which are repeated over and over
What do non coding sequences do
- Regulate transcriptions
- Transcribed into RNA but never translated, like tRNA
What…
- Regulate transcriptions
- Transcribed into RNA but never translated, like tRNA
Non-protein-coding regions
Mutations
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised
Mutations
Mutations arise ______ and at _______
Mutations arise spontaneously and at random
What do mutation rates differ between
Different genes and different organisms
Types of mutations
- Single gene mutations
- Chromosome structure mutations
- Single gene mutations
- Chromosome structure mutations
Types of mutations
Single gene mutations
A change in one of the base pairs in the DNA sequence of a single gene
A change in one of the base pairs in the DNA sequence of a single gene
Single gene mutations
What do single gene mutations occur in
The protein coding sequence or the regulatory sequences which control expression of the gene
What occur in the protein coding sequence or the regulatory sequences which control expression of the gene
Single gene mutations
Three single gene mutations
- Deletion
- Insertion
- Substitution
- Deletion
- Insertion
- Substitution
3 types of single gene mutations
Deletion
One nucleotide is deleted from the nucleotide sequence
When one nucleotide is deleted from the nucleotide sequence
Deletion
One nucleotide is inserted into the nucleotide sequence
Insertion
Insertion
One nucleotide is inserted into the nucleotide sequence
One nucleotide is swapped for another nucleotide in the sequence
Substitution
Impact of single gene mutations
Missense mutations
Nonsense mutations
Splice site mutations
Frameshift mutations
Missense mutations
Nonsense mutations
Splice site mutations
Frameshift mutations
Impact of single gene mutations
Missense
One amino acid is changed for another
May result in a non functional protein or have little effect on protein
One amino acid is changed for another
May result in a non functional protein or have little effect on protein
Missense
Nonsense
Premature step codon produced
Shorter protein synthesised
Premature step codon produced
Shorter protein synthesised
Nonsense
Splice site mutation
Some introns being retained and/or some exons not being included in mature transcript
Protein doesn’t function properly
Some introns being retained and/or some exons not being included in mature transcript
Protein doesn’t function properly
Splice site mutations
Thalassemia
Disease caused by a defect inhoemeglobin synthesis, caused by a splice site mutation
Disease caused by a defect inhoemeglobin synthesis, caused by a splice site mutation
Thalassemia
Example of splice site mutation
Thalassemia
Mutations from substitutions
Missense
Nonsense
Splice site
A mutation in what can result in….
Missense
Nonsense
Splice site
Substitution
Frame shift mutations
Cause all of the codons and amino acids after the mutationto be changed
Has a major effect on the structure of the protein produced
all of the codons and amino acids after the mutationto be changed
Has a major effect on the structure of the protein produced
Frame-shift-mentations
What causes frame-shift mutations
Insertion or deletion
What does insertion cause
Frame shift mutations
What does deletion cause
Frame shift mutations
Chromosome structure mutations
A change in the chromosome structure due to the breakage of one a more chromosomes
A change in the chromosome structure due to the breakage of one a more chromosomes
Chromosome structure mutations
The substantial change in chromosome mutation results in what
Lethal
What can be the result of insertion
Frame shift mutations
What can be the result of substitution of a gene
Missense mutations
Nonsense mutations
Splice site mutations
What can be the result of deletion
Frame shift mutations
Types of chromosome structure mutations
Deletion
Duplication
Inversion
Translocation
Deletion
Duplication
Inversion
Translocation
Types of chromosome mutations
Chromosome deletion
A section of a chromosome is removed
A section of a chromosome is removed
Chromosome deletion
Effect of chromosome deletion
Drastic effect as genes are lost
Example of chromosome deletion
Deletion of a party of chromosome 5 leads to Cri du Chat
Duplication
A section of a chromosome is added from its homologous partner
A section of a chromosome is added from its homologous partner
Duplication
Effects of duplication
Set of genes are repeated
Can be detrimental but also important in evolution
Set of genes are repeated
Can be detrimental but also important in evolution
Duplication
Example of duplication
Duplication of oncogenes is a common cause of cancer
Evolutionary importance of gene duplication
Allows potential beneficial mutations to occur In a duplicated gene whilst original gene can still be expressed to produce its protein
Inversion
A section of chromosome is reversed
A section of chromosome is reversed
Inversion
Example of inversion
One cause of haemophilia A is the inversion within a blood clotting gene
Translocation
A section of one chromosome is added to another chromosome, not its homologous partner
A section of one chromosome is added to another chromosome, not its homologous partner
Translocation
Example of translocation
One type of Down’s syndrome is caused by this
Evolution
The changes in organisms over generations as a result of genetic variation
The changes in organisms over generations as a result of genetic variation
Evolution
Natural selection
The non random increase in the frequency of DNA sequences that increase survival and the non random decrease in the frequency of deleterious sequences
The non random increase in the frequency of DNA sequences that increase survival and the non random decrease in the frequency of deleterious sequences
Natural selection
Deleterious sequence
Any sequence that may produce a protein that causes harm
Any sequence that may produce a protein that causes harm
Deleterious sequence
Gene pool
The total of all the different genes in a population
The total of all the different genes in a population
Gene pool
What happens if a species is under no selective pressure
Frequencies of individual alleles will stay the same from generation to generation
Types of selection
Stabilising
Directional
Disruptive
Selection pressure
An environmental change that affects an organisms ability to survive and reproduce
An environmental change that affects an organisms ability to survive and reproduce
Selection pressure
Example of selection pressure
Increased competition
Temperature change
New diseases
Stabilising selection
An average phenotype is selected for and extremes of the phenotype are selected against
An average phenotype is selected for and extremes of the phenotype are selected against
Stabilising selection
What does stabilising selection cause
Reducing in genetic diversity
Directional selection
One extreme of the phenotype range is selected for
One extreme of the phenotype range is selected for
Directional selection
When is directional selection common
During periods of environmental change
What selection happens during periods of environmental change
Directional selection
Disruptive selection
Two or more phenotypes are selected for
Two or more phenotypes are selected for
Disruptive selection
What can disruptive selection result in
The population being split into two
What does vertical transfer happen by
Asexual and sexual reproduction
Natural selection happens much more _________ in prokaryotes
Quickly
Why can prokaryotes go through natural selection much faster
Prokaryotes can exchange genetic material horizontally
Vertical transfer
The transfer of genetic sequences from parents to offspring
The transfer of genetic sequences from parents to offspring
Vertical transfer
Horizontal transfer
When genes are transfer between individuals in the same generation
When genes are transfer between individuals in the same generation
Horizontal transfer
Species
a group of organisms capable of interbreeding and producing fertile offspring
a group of organisms capable of interbreeding and producing fertile offspring
Species
a group of organisms capable of interbreeding and producing fertile offspring
Species
Speciation
The generation of new biological species by evolution
The generation of new biological species by evolution
Speciation
Types of speciation
Allopathic
Sympatric
Geographical barriers cause……
Allopatric speciation
Behavioural barriers cause……….
Sympatric speciation
Ecological barriers cause…….
Sympatric speciation
Allopatric speciation
When gene flow between 2 or more populations is prevented by a geographical barrier
When gene flow between 2 or more populations is prevented by a geographical barrier
Allopatric speciation
Allopatric speciation example
Rivers
Sea
Mountain ranges
Steps of speciation
- Isolation
- Mutation
- Natural selection
- Speciation
Sympatric speciation
Two or more populations live in close proximity in the same environment, but still become genetically isolated
Two or more populations live in close proximity in the same environment, but still become genetically isolated
Sympatric speciation
What causes Sympatric speciation
Behavioural or ecological barriers
What causes allopatric speciation
Geographical barrier
Ecological barrier
Groups not genetically isolated from each other
Isolated by other things such as occupying different habitats or breeding areas
Groups not genetically isolated from each other
Isolated by other things such as occupying different habitats or breeding areas
Ecological barrier
Behavioural barrier
Breeding between groups working a population may not be possible because of differences in courtship behaviour
Breeding between groups working a population may not be possible because of differences in courtship behaviour
Behavioural barrier
Stage 1 of speciation
Large interbreeding population sharing the same ecological niche
Large interbreeding population sharing the same ecological niche
Stage 1 of speciation
Stage 2 of speciation
Alternative ecological niches appears
Some members of the population start to exploit this niche
Alternative ecological niches appears
Some members of the population start to exploit this niche
Stage 2 of speciation
Stage 3 of speciation
The two populations now exploit different resources and no longer interbreed
Behavioural had become an isolating barrier
The two populations now exploit different resources and no longer interbreed
Behavioural had become an isolating barrier
Stage 3 of speciation
Stage 4 of speciation
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
Stage 4 of speciation
Stage 5 of speciation
Natural selection factors the new mutants
and eventually over a period of time two genetically distinct species are formed which can no longer interbreeding
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
Stage 5 of speciation
genomics
the study of genes
the study of genes
genomics
What must you first do to study genomics
Determine the entire DNA sequence of the organism
When was the entire human genome sequenced
2003
Reasons for genomic sequencing
accurate diagnoses
specific pest control
Model sequencing
Genomic sequencing accurate diagnoses
Disease causing organisms have been sequenced
Eg. Viruses to help with accurate diagnoses
Genomic sequencing, specific pest control
Pest sequences have been sequenced to develop more specific measures to control rather than using general pesticides
Genomic sequencing, model sequencing
Model organisms have been sequenced so that they can be used in medical research in place of mammals,
reducing ethical concerns and costs
Bioinformatics
The use of computers and statistical analysis to identify and compare sequence date
The use of computers and statistical analysis to identify and compare sequence date
Bioinformatics
What can computer programs be used for in bioinformatics
To identify base sequences by looking for sequences similar to known genes
What can highly conserved dna sequences by used for
To compare the genomes of two species
What can be used to compare the genome of two species
Highly conserved DNA sequences
Highly conserved sequences means..
Species more closely related
Phylogenetics
The study of evolutionary history and relationships
The study of evolutionary history and relationships
Phylogenetics
What do phylogenetic trees show
How organisms are thought to have evolved into different species over time
What shows how organisms are thought to have evolved into different species over time
Phylogenetic trees
The further apart the species are on a phylogenetic tree………
The more distantly related they are
Over time, a group of closely related relative living things will accumulate __________ that will gradually __________
Mutations
Alter the genome
What do molecular clocks show
When species diverged during evolution
What do molecular clocks assume
A constant mutation rate
Requirements for molecular clocks
Genome sequence dna
Fossil evidence
Pharmocogenetics
The use of genome information in the choice of drugs
The use of genome information in the choice of drugs
Pharmocogenetics
What could knowing the genome sequence of a person be used for
Select the most effective drugs
And dosages
DNA in prokaryotes
Circular chromosomes and plasmids
Where is dna found in prokaryotes
Cytoplasm
Eukaryotes dna
Linear chromosomes packaged with histones
Circular chromosomes found in mitochondria
Where is linear dna found in eukaryotes
Nucleus
Exception in eukaryotes
Yeast has plasmids
Transcription summary
RNA polymerase unwinds DNA
hydrogen bonds between bases break
RNA polymerase attaches rna nucleotides with their complementary nucleotides
A primary transcript is produced
Exons - coding regions
Introns - non coding regions
Exons are spliced together to form mature transcript
Translation
tRNA has an amino acid attachment site and an anti codon attachment site
tRNA carries its specific amino acid
Anticodons are complementary with codons on mRNA
There are start and stop codons on mRNA
peptide bonds firm between amino acids
