Genetics Flashcards
What is a phenotype
Expressed genes which can be seen like hair or eye colour
What is an allele
A form of a gene (e.g different blood types A,B,O,AB)
What is a gamete
A reproductive cell of a plant or animal
What is homozygous/homologous
Same pair of genes (e.g RR or rr)
What is a heterozygous/heterozygote
One of each cell (e.g Rr or rR)
What is a recessive gene
A gene only expressed when both genes are homozygous “lowercase” (e.g rr)
What is a genotype
Inherited genes
What is co-dominance (in genes)
When both genes for the characteristic or trait are expressed in a mixture (e.g a red flower and white flower create a pink flower)
What is a dominant gene?
A gene that’s expressed if you have one or more dominant/“uppercase” genes (e.g Bb creates blue eyes ) these can be heterozygous or homozygous
What is huntingtons chorea?
A dominant genetic disease which ruins nerve coordination which is fatal but only comes into effect in late 40s and there is no cure
What is haemophilia?
A recessive genetic disease. It affects blood and means you cannot clot your blood so you will bleed to death if you cut yourself and it’s sex/gender related (women can be carriers but men either get it or they don’t )
Advantages of genetic screening?
-Provides parents with choice of whether to have a child or risk a genetic disease?
-Allows parents to prepare financially and emotionally
-Reduces number of people with genetic diseases
Disadvantages of genetic screening?
-Encourages abortion which goes against many religions
-Genetic screening can be expensive
-Screening puts embryo at risk at there is a small chance of miscarriage
-May harm the mother
What is a carrier (genetic disease)
Someone who has half the gene disease (recessive) but is not unwell (they need to be homozygous to be ill)
What is PGD?
Pre-implantation genetic diagnosis (which is a genetic screening done before the embryo begins growing)
What is CVS?
Amniocentesis (which is a genetic screening done 10-14 weeks into pregnancy)
What is genetic engineering?
The deliberate modification of an organisms genes
What is a plasmid?
A small circular DNA molecule found in bacteria and some other microscopic organisms
What enzyme is used to cut a plasmid
R.E (restriction endonuclease)
What is the name of the enzyme that converts RNA into DNA
Reverse Transcriptase
Once a plasmid is cut with RE what two things are inserted?
-New DNA code for whatever the purpose of the bacteria is (e.g insulin)
-marker gene
How is the DNA and genetic marker inserted into the plasmid?
Using Ligase enzyme (sticking enzyme)
What is the purpose of the marker in the plasmid
To check if the bacteria was effective (e.g a fluorescent gene is used and if the bacteria glows then it has worked)
What is the term given to an organism that has been taken apart then remade (with or without modifications)
Recombinant Organism
How do bio reactors work?
-bacteria is inserted into a clean stainless steel container with a broth (sterile) inside
-the bacteria feeds off the broth and multiplies
-Once it multiplies past a point it is emptied to half the volume
-The broth is refilled and this keeps looping to end up with millions of copies of the bacteria
What is restriction enzyme
Used to cut a section of DNA from a longer strand
What is a lipozyme
Used to break open a bacterial cell so plasmid can be removed
What enzyme is used to “cut” a plasmid
R.E (Restriction Endonuclease)
Once the plasmid is cut what is inserted?
New DNA coding for human insulin (or whatever is being produced) which is made from pancreas RNA and R.T
What enzyme is used to Revert RNA to DNA
R.T enzyme
What enzyme is used to “stick” the plasmid back together?
Ligase enzyme
What else is inserted into a plasmid that has been cut up besides DNA coding
A marker
Why is the marker put into the plasmid?
To have a visual check if it has worked
What is an example of a marker?
Glow in the dark gene
Where is the insulin cell (with now augmented plasmid) placed to grow?
Agar plate where it is checked for the marker, whether it’s via antibiotic resistance or see if its fluorescent
How does a bioreactor work?
-The bacteria is insterted into a large broth (sterile) which is kept a constant temperature.
-In the broth it will divide
-once it doubles it is emptied till half before being refilled with more sterile broth
-This process is repeated ending up with millions of replicated cells where the insulin (or whatever is being made) is then extracted
What is the difference between mitosis and meiosis
Mitosis
-Splits to 2 pairs
-Genetically
Identical
-Diploid
-Quick process
-For Growth and Repair
Meiosis
-Creates 4 Cells (Gametes)
-Genetically Variable
-Haploid
-Slow
-Used for sexual reproduction
In protein synthesis, what enzyme “unzips” the DNA?
Helicase
What enzyme makes the mRNA in protein synthesis?
Polymerase
What happens to an RNA strand over time?
It disintegrates as a single strand doesn’t live long (but more mRNA can be made)
What are the 4 bases in DNA
A,G,C,T
Adeline, Guanine, Thymine, Cytosine
What is the tRNA?
The “dropper” for the amino acids on the mRNA
What is the requirement for the tRNA to drop an amino acid?
The anti-codon must be a match for the codon on the strand
What is a codon? (Protein synthesis)
Three bases in a strand of mRNA
What do ribosomes do in protein synthesis to the mRNA
Create “strings” of protein
How many RNA s are there and what do they do
-mRNA= message RNA - copies DNA and is the foundation for protein being made
-ribosomal RNA =contains the “dropper” and makes the “strings” of protein
-tRNA= the “dropper” which drops the amino acid when the anti codon and codon match
What are the components of DNA
Phosphate group
Pentose sugar (deoxyribose)
Nitrogenous base
What are the pairs in the DNA bases
A + T
G + C
What does DNA stand for?
Deoxyribo-Nucleic-Acid
What is the name for an organism that has been edited genetically and put back together (e.g plasmid to make insulin)
Recombinant Organism
