2C: Inheritance Flashcards
what is the process of DNA replication
- DNA helicase breaks the hydrogens bonds between the two polynucelotide strands
- complemtary base pairing takes place with each single template strand
- condensation reactions join the nucleotides of the new strands together and hydrogen bonds form between the new and OG strands
- each new DNA molecule contains one strand from original DNA strand
what is the role of DNA polymerase
to make sure the dna is accurately copied and to keep maintenance of the gene
how did meselson and stahl prove DNA replication was semi-conservative
DNA settled between the top and bottom of the centrifuge, proving that during replication, the DNA is mixed
how does genetic muatations happen
changes in AA sequence which affects the function of a protein
- DNA replication errors
how does a chnage in AA sequence affect the protein
the primary structure can change
- changes function
- changes shape
what DNA replication errors can happen
substitution
deletion
insertion
duplication
inversion
what is DNA substitution
one base is substituted another
- bases get swapped
what is DNA deletion
one base gets deleted from sequence
what is DNA insertion
an extra base is added to sequence
what is DNA duplication
one or more bases are repeated/ copied twice
what is DNA inversion
sequence of bases get reversed
what is a gene
a sequence of bases that code for a protein for certain characteristics
what is allele
different types of a gene ie blue eyes allele or brown eye allele
what is a genotype
the alleles a person has
what is a phenotype
the characteristics displayed by an organism due to their alleles
what is incomplete dominance
when a trait from a dominant allele is not completely shown so both alleles influence phenotypes
How does CF affect the respiratory system
due to thick and sticky mucus
- cilia unable to move mucus towards throat therefore airways get blocked
- can prevent gas exchange from taking place therefore smaller SA for gas exchange to take place resulting in breathing difficulties
- more prone to lung infections
how does CF affect the digestive system
- the tube connecting pancreas to small intestine can become blocked - preventing digestive enzymes reaching the small intestine -> less nutrients absorbed from food and reduced ability to digest food
- mucus can cause growth of cysts in pancreas -> inhibits production of enzymes
- mucus lining small intestine is abnomally thick therefore inhibiting absorption of nutrients
how does CF affect the reproductive system
- in men, the tubes between reproductive organs can become blocked and no sperm can reach the p*
- in women, thickened cervical mucus prevents sperm from reaching the egg therefore reduces mobility of sperm and reducing likelihood of sperm reaching the egg
what is genetic screening
scanning DNA to analyse if it contain genetic diseases
what are the main uses of genetic screening
- identify genetic disorder carriers
- preimplatation genetic disorders ( reduces chance of having a baby with genetic disorder)
- prenatal tetsing (2 types)
what are the two types of prenatal testing
aminiocentesis and chrionic villus sampling
what happens during amniocentesis
a sample of amniotic fluid is taken using a very fine needle
when is amniocentesis carried out
15-20 weeks into pregnancy
risks of amniocentesis
1% of miscarriage
what happens during chorionic villus sampling
sample of cells is taken from chorionic villi ( part of the fetus)
- done via abdomen w fine needle or via v* w a catheter
risks of CVS
1-2% of miscarriage
when is CVS carried out
11-14 weeks in pregnancy
what are the social and ethical concerns with genetic screening
- parents make informed decision on if an abortion is needed or not
- false positives can lead to abortion of a healthy baby
- quality of life of a child w genetic disorder isn’t always bad
- unethical and immoral to abort baby just bc it has a genetic disorder
