Task 1 Flashcards
Replication, Transcription, Translation
Phenotype
observable characteristics
Genotype
complete heritable genetic identity
Alleles
Variations on your genes which is on your chromosomes
e.g. variation one gene 19 with one allele for blue eyes and one allele for green eyes
Diploid
Organisms/cells with two copies of each gene
Haploid
Organisms/cells with only one copy of each gene
Central Dogma of genetics
Genotype can influence the Phenotype, but not vice versa = The flow of info is one-way
What are somatic lines?
every cells except of gametes e.g. skin cells or heart cells
=> making more phenotypes
- Mitosis
- whole genetic material
What are germ lines?
produces gametes
e.g. sperm in males, egg cells in females
=> making more genotypes
- meiosis
- half of the genetic material
What are autosomes?
autosomes are the first 22 pairs which are numbered by size and are the same in both sexes
=> Diploid
What are Sex chromosome ?
The last chromosome number 23
- females XX
- Males XY
=> Haploid
What is the DNA?
A long chain molecule entailing 2 strands bound to each other and twisted around each other in a double helix
Out of what does the DNA consist?
- each strand is made up of a backbone of sugar and phosphates
- along each backbone are sequences of four bases: Adenin, Thymine, Cytosine; Guanine
- the bond within each strand are extremely strong => Covalent bonds
- The bonds between both strands are weaker => Hydrogen bonds
- Base pairing: A+T and C+G
What can the DNA do?
- Copies itself (Replication)
2. Makes Phenotypic material (Transcription and Translation)
What is the Start codon?
AUG = Start
- initiates the process of translation
- Methionin
What are the Stopp Codons?
UAG, UGA and UAA indicate the end
sound like monkeys
Is the Genetic code robust against errors?
- in general the code is robust against errors
- Synonymous substitution
= reading the third base wrongly, mostly won’t affect the amino acid - Non-synonymous substitution
= error in reading the first base wrong = DRAMAAA
What are Non-coding genes?
Introns, usually transcribed but not translated
- more introns than exons
- not everything is Junk as people thought for a long time
Function:
- may have regulatory functions
- may enhance genome’s evolvability (= ability to generate novel phenotypes)
- Transposable elements promote the reshuffling and reduplication of genetic material during meiosis
- possibly responsible for the phenotypical differences between and within species
Recombination / Crossing over
during meiosis, paired chromosome line up next to each other and exchange DNA
= sequence that was originally on chromosome A ends up on chromosome B and vice versa
What is independent segregation and linkage?
- the physically closer two genes are on a chromosome = the greater the degree of genetic linkage
- the probability of recombination events of breaking them apart is related to the distance between them
Describe the mutation form that leads to gene SUBSTITUTION
Substitution = replace one pair with another
C/T or G/A are chemically similar = Transition
- similar occur more often
C/G or C/A are dissimilar pairs = Transversion
Describe the mutation form that leads to gene
EXPANSION AND CONTRACTION
expansion and contraction is a repetition of a simple sequence (added or lost)
Describe the mutation form that leads to gene
INSERTION
insertion is when one pair is inserted, which change the whole sequence
= different protein synthesis
Describe the mutation form that leads to gene
DUPLICATION
duplication is two time the same gene
- two copies, whereas one can get mutated and acquire new functions and the other stays with the original form
What is a Locus?
a particular site in the genome, like a specific place on the chromosome
e.g. the locus of an allele
What is Polymorphism?
A locus for which there is more than one allele in the population
SNPs = single nucleotide polymorphism: something like one in every single 100 single bases varies from individual to individual
When Mutations have an phenotypic effect it is usually harmful but why?
Mutations are undirected => the effect of the mutation is unrelated to the physiological needs and functions of the phenotype
=> so its more likely that it functions less well
What are polygenic traits?
variations in the phenotype is related to which allele is present across a number of genes
e.g. height
What is the effect of injection of Vasopressin?
vasopressin is a hormone which injected lead to greater pair bonding
What happens when MAOA is lacked?
MAOA = Monoamine oxidase
- an enzyme that breaks down serotonin (regulation of Mood states)
- lack of MAOA may lead to violence and aggressive behaviour
What is Transcription?
Transcription is the synthesis of RNA using information in the DNA
- DNA serves as a template for assembling a complementary sequence of RNA nucleotides
- through modification RNA => mRNA (splicing)
Where does transcription takes place?
Transcription and modification processes takes place in the nucleus
What is translation?
Translation is the synthesis of polypeptides using the information in the mRNA
=> translate into proteins
Where does translation takes place?
outside of the nucleus with Ribosomes
In which direction is the mRNA written?
the mRNA is transcribed from the codogener /Antisense strang
- Antisense = 3’-5’
- mRNA = 5’-3’
Which kind of polymerase is used in Replication and which one in Transcription?
Replication = DNA polymerase
Transcription = RNA Polymerase
from which direction does the polymerase start to replicate the DNA strang?
from the Leading stand = 3’-5’
Lagging stand = 3’-5’ but with Okazaki Fragments
Explain the process of replication
- Topoisomerase untwist the DNA
- Helicase opens the DNA
- Primer binding
- DNA polymerase start to replicate (from 3’-5’)
- Problem with lagging strand
- opposite direction, can only replicate from 3’-5’
- therefore, replicate, then new primer bind to it, then replicate the next part etc etc.
=> OKIZAKI FRAGMENTS - Enzyme remove primer and Ligase put fragments together
END
Explain the process of Transcription
- takes place in the nucleus
- we have a codogener/Antisense strang and a sense strang
- RNA polymerase replicate the Antisense strang to receive the sense strang
- we have a promotor (start) and a terminator stop (Stop)
- after formation of RNA = modification (cap&tail, editing, splicing) => mRNA
Explain the process of Translation
- takes place out of the nucleus
- at ribosomes (consist of two parts)
- ribosome wander over the mRNA as long as it finds a start codon (AUG) than start to translate it into proteins
- ribosome has 3 binding points
- tRNA brings the fitting pairs
- create a long polypeptid
= Proteins
There are some point mutations (changes in a single nucleotide pair of gene)
so what is a silent mutation?
- also called synonymous
Silent mutation = substitutions that have no effect on the encoded protein
=> no observable effect on phenotype
There are some point mutations (changes in a single nucleotide pair of gene)
so what is a missense mutation?
missense mutation = substitutions that change one amino acid to another
- > little effect on the protein
- > depends on the place
There are some point mutations (changes in a single nucleotide pair of gene)
so what is a non- sense mutation?
non-sense mutation = change a codon in a stop codon
-> causes that the translation stops
What are frameshift mutations?
= insertion and deletion
What is a histone acetylation ?
histone acetylation
= the process of loosens the structure, so that transcription is easier
what is DNA methylation?
= tagging specific points in the DNA molecule wit Methyl group
-> blocks the unwinding or the transcription of the DNA
= Inactivation of genes, silencing the gene
How many amino acids do we have?
there are 64 possible triplet codons, and only 20 amino acids
What is alternative splicing?
mRNA is spliced to create different transcripts which are then translated into different proteins
=> more variation
What is a codon?
a sequence of Three base pairs, that code for a amino acid = protein
What is the hypothesis of the article “from genes to brain to antisocial behaviour” ?
Hypothesis:
Specific genes result in structural and functional brain alterations that in predispose to antisocial behaviour
Which genes can predispose one to antisocial behavior? (article)
MAOA = aggression in mice
-> maoa codes for an enzyme that breaks down serotonin, a NS which is low in anti social individuals
and 7 other genes that is also associated with aggression
How does one progress from genes over the brain to antisocial behaviour ? (article)
Gene abnormalities => structural brain abnormalities => emotional, cognitive and behavioral abnormalities = predisposition to antisocial behaviour
How does structural brain impairments give rise to antisocial behaviour ? (article)
Neural moral theory:
Antisocial individuals have a breakdown in the neural circuit normally activated during moral decision making
MPFC,VPFC, angular gyrus, amygdala etc some of those areas disrupt moral emotion and decision making = rule breaking
Can the environment change gene expressions? (article)
yes, environmental influences early in development can change gene expressions
- the social environment can interact with genetics and biological risk factors
- antisocial behaviour is exponentially increased when social and biological risk factors are combined
What is epigenetic?
epigenetics is the modification of DNA which change gene expression
- may be heritable or not
- does not involve changes to the underlying DNA sequence
- change phenotype without changing genotype
- affects how cells read the genes
- could explain how early life experiences can leave a mark on the brain and influences both behaviour and physical health
Why is the way of nurturing important? (article)
- the way how rats nurture their pubs influences how they respond to stress later in life
- less nurturing lead to increase methylation of the gene BDNF (neural growth factor) or reduce glucocorticoid receptors (important for learning and memory in the hippocampus)
- chronic stress lead to an increase in histone methylation that suppress gene activity by keeping the DNA containing the BDNF gene tightly wound
What about antidepressant and acetylation?
Antidepressant can boost histone acetylation, which helps unwind DNA from histones and promote BDNF activity
