Component 2 Flashcards
Acrosome reaction
Acrosome enzymes digest the corona radiata and the zona pellucida
Allele
A version of a gene at a given locus which codes for an altered phenotype
Allele frequency
Proportion of all the genes in the gene pool
Allopatrick speciation
Revolution of a new species from isolated populations by a geographical boundary
Capacitation
Removal of glycoproteins and cholesterol coat which increases permeability of the membrane to Ca+ and increases chances of bonding to allow acrosome reaction to occur
Carrier
Heterozygous for one dominant allele and one mutant recessive allele
Cortical reaction
Fusion of cortical membranes with oocyte membrane due to calcium ions being transported into the cytoplasm for SER. This causes zona pellucida to expand and harden
Dehiscence
Opening of the anther releasing pollen grains
DNA ligase
Enzyme that joins together portions of DNA by catalysing the formation of a phosphodiester bond
Dormant
Active growth of the seed is suspended
Electrophoresis
Separates molecules on the basis of size by rate of migration under an applied voltage
Epigenetics
The control of gene expression by modifying DNA or histories which does not effect the nucleotide sequence
Evolution
Change in allele frequency and the average phenotype of the population over time
Founder effect
The loss is genetic variation in a new population established by a very small number of individuals from a larger population
Fruit
Structure developing from ovary wall containing one or more seeds
Gene
Sequence of dna that codes of a polypeptide and occupies a specific locus on a chromosome
Gene pool
All alleles present of all the individuals in a population at a given time
Genetic drift
Change in allele frequency due to chance in a small population
Germination
When the seed becomes a photosynthesising plant
Hybrid
Off spring is a cross of different species
Linked
Genes are on the same chromosome and therefore do not segregate independently in meiosis
Non disjunction
Fault cell divisions no in meiosis where one of the daughter cells receives two copies of one chromosome and the other receives none
Plasmid
Small circular loop of DNA bacteria which is double stranded
Polyploidy
Having more than two complete sets of chromosomes
Primer
Single strands of DNA complementary to larger section of DNA that is going to be copied. Signals polymerisation to start
Recombinant DNA
DNA produced by combining DNA from two different species
Reproductive isolation
Prevents reproduction and gene flow between breeding groups in a species in an environment
Restriction endonucleases
Cuts sugar phosphate backbone at specific restriction sites
Reverse transcriptase
Catalysed the synthesis of DNA from an RNA template
Seed
Contains an embryo and food store within a testa
Sex linkage
Gene is located on X chromosome so is more likely in males than females
Speciation
Formation of a new species
Species
Group of organisms that can interbreed to produce fertile offspring
Stem cell
Undifferentiated cell capable of diving to give rise to daughter cells which can develop into any type of cell
Sticky end
Sequence of unpaired bases which are staggered and exposed
Sympatric speciation
Evolution of a new species from populations sharing the same environment
Test cross
Cross with homozygous recessive
Transgenic
Organism genetically modified by the addition of genes from another species
Trophoblast
Cells forming outer layer of blastocyst
Variation
Difference between organisms of the same species
Mitosis
Cell devision forming two genetically identical daughter cells with same number of chromosomes
Classification
Organisation of organisms into groups according to shared similarities
3 domains
Eubacteria
Archea
Eukaryotes
Analogous
Same function but different structure = not related
Homologous structures
Same structure different functions = divergent evolution
Biodiversity
Number of species and number of organisms of each species in an environment
3 types of adaptations
Anatomical (body shape = streamlined)
Physiological (leaves fall of with low light intensity and cold)
Behavioural (flowers in spring with pollinating insects)
Interstitial cells
Secrete testosterone for secondary sex characteristics
Sertoli cells
Nourish cells and protect from immune system
Solid ball of cells
Morula
First hormone secreted
GnRH
Function of progesterone
Produced from corpus luteum
Maintains endometrium and inhibits FSH
Function of oestrogen
Builds endometrium Inhibits FSH Stimulates LH Secondary sex characteristics Inhibits prolactin and oxytocin
Function of FSH
Stimulates Graafian follicle
Stimulates oestrogen
I’m
2 synergid cells
Aid ferlisation
3 antipodals
Direct nutrients
Pollination
Transfer of pollen grains from another to nature stigma
Self pollination
Pollen from anther is transferred to stigma of same flower or plant
Cross pollination
Pollen transferred from anther to stigma on a flower of a different plant of same species
Ensuring cross pollination
Dichogamy Anther below stigma Male and female flowers Male and female plants Genetic incompatibility
Why is maize a fruit
Testa fuses with ovary wall
What is the testa formed from
Integuments and lignin
Codominant
Both alleles have an affect on phenotype of heterozygous as both are expressed eg. Blood type AB
Incomplete dominance
Phenotype of the heterozygous is half way between the two alleles
Dihybrid cross
Cross between two individuals for two genes of different chromosomes
Assumes all allele combinations are equally likely and down to random assortment
Recognising linkage
Cross over value
Kai squared
Critical value
Degrees of freedom = number of sums -1
Use 0.05 probability value
Mutations
Change in amount arrangement structure of DNA
When do mutations occur
Crossing over in prophase 1
Non disjunction in anaphase 1/2
Increased rate in mutations
Ionising radiation
Mutagenic agents eg. Agent orange
Type of mutations
Genepoint
Chromosome
Aneuploidy
Polyploidy
Gene point mutation
DNA not copied correction
Chromosome mutation
Damaged or broken chromosome not repaired correctly
Aneuploidy mutation
Chromosome is lost or added through non disjunction
Polyploidy mutation
Double number of chromosomes due to
- endomitosis
- fusion of two haploid cells
- defect in spindle fibres
Types of gene mutation
Substitution Addition Deletion Inversion Duplication
Sickle cell anaemia
Substituting of val to glu Change in tertiary Insoluble Stick together Sickle shaped Reduces oxygen binding
Chromosome mutation
Change in structure and number of whole chromosomes
Eg. Breaks and doesn’t rejoin or non disjunction
Down’s syndrome
Down’s syndrome
Extra chromosome 21 from nondisjunction of oocyte
Translocation downs when a bit breaks off and attaches to another chromosome
Proteins that’s regulate cell division
Protooncogenes
Tumour suppressor genes
Malignant cancer
Cells break off and travel in blood to form secondary tumour = metastasis
2 ways of epigenetixs
Histone modification
DNA methylation
4 types of variation
Heritable
Non inheritable
Continuous
Discontinuous
Heritable variation
Mixing of parental genotypes
Crossing over
Random assortment
New allele combinations
Non inheritable
Environmental influences determine phenotype
Eg. Diet exercise
Not passed on
Continuous
Multiple genes polygenic
Graduation between extremes
Genetic and environmental
Discontinuous
Single gene mono genic
Discreet variables
Genetic only
Not gradation
Causes of variation
Mutation
Crossing over
Independent assortment
Random gamete formation
Environmental influence on cytoplasmic level (non inheritable)
Environmental influences on gene expression (epigenetics)
4 types of selective agents
Environmental factors eg. Fire global warming
Human influence eg. Antibiotics weed killers
Inter specific competition
Intraspecifc competition g
3 types of selection
Stabilising
Directional
Disruptive
Selection pressure
Environment factor that can alter the frequency of alleles in a population when it is limiting
Natural selection
Increased chance of survival and reproduction of organisms with phenotypes suited to their environment enhancing the transfer of favourable alleles between generations
Selection
Process that better adapted organisms are more likely to survive and breeed and pass on characteristics
Bottleneck
Disaster killed all by few individuals which changes alleles frequency
How many new species arise
Polyploidy
Isolation = restriction of gene flow
Reproductive isolation
Prevent of reproduction and gene flow between breeding groups in a species
Prezygotic isolation
Geographical Behavioural Morphological Gamete isolation Seasonal
Postzygotic
Hybrid inviability
Hybrid sterility
Hybrid breakdown
Harvey Weinberg features
Large population No mutations Random mating No selective agents No immigration or emigration
Harvest Weinberg equations
P = frequency of dominant allele Q = frequency of recessive allele P2 probability of homozygous dominant Q2 probability of homozygous recessive 2pq probability of heterozygous
Sanger sequencing
Cut up DNA Add dideoxynueotide to present polymerisation Mark end nucleotide with marker Add stop nucleotides Gel electrophoresis
Aims of human genome
determine order of bases in genome
Identify genes and mapping
Chloroquine
Delays haemoglobin digestion by the parasite
Getting the vector
EDTA to destabilise cell wall
Detergent
NaOH
Centrifuge
Two gene markers
Amphicillin
Tertracycline
Where is the gene for insulin
In tetracyline gene
GM tomatoes
Add gene with complementary sequence to the gene that codes for pectin which break down the tomatoes
Gene therapy
A working copy of the gene in placed into cells that contain a non functioning gene or repair gene by changing expression
Somatic cell therapy
Replacing fault genes with correct copies in certain body tissues so genes can’t be inherited
Germ line
Gene is inserted into embryo or gamete or all new cells contain new gene
Duchenne muscular dystrophy cause
Deletion creates frame shift
Lack of dystrophin so muscles break down and are replaced by fibrous tissue and fatty deposits
Sex linked m
Treatment for DMD
Drisapersen injections which restore reading frame by being complimentary to the mutated DNA part so section is not translated
Autologous cells
Cells from same individual
Allogenic cells
Donor of same species
Xenogenic
Cells from another species
Synergic cells
From genetically identical organism
Benefits of a scaffold
Cells can attack
Delivers and retains cells
Porous for diffusion
Biodegradable
Types of stem cells
Embryonic
Adult
Genericalll reprogrammed by viruses
Uses of stem cells
Tissue engineering
Cell based therapies
Screen for new drugs
