Genetics Inheritence Flashcards
What are chromosomes?
Structures within a cell nucleus that contain DNA (genetic information)
What is a gene?
A specific sequence of DNA. They code for a specific protein or RNA.
What are gene variants/alleles?
They have different DNA sequences than the ‘normal’ gene
What is genetics?
The study of genes, genetic variation, and heredity
What is heredity?
The transmission of traits from one generation to the next
Why is Gregor Mendel the father of genetics?
He was the first person to experimentally analyse patterns of inheritance using pea plants as his model system in 1866
What is a model system?
An organism that makes it easy for a researcher to investigate a particular scientific question
They then apply their findings to harder to study organisms
What is the blending model of inhertiance?
Inheritance involved the permanent blending of parents’ characteristics in their offspring
Why was the blending model full of holes?
Could not explain why when Mendel crossed a pure bred tall and short pea plant, he only got pea plants
Also could not explain why self fertilisation of the above tall plants would produce a 3;1 ratio of tall to short plants
What does true breeding mean in terms of mendelian genetics?
An organism must be homozygous for every trait for which it is considered true breeding
How are peas cross-pollinated and self pollinated?
Cross: Transfer pollen with brush then remove anthers
Self: Transfer own pollen to own stigma
Which traits of pea plants did mendel observe?
Format: Trait - Dom trait vs Rec trait Colour - Purple vs white Position - Axial vs terminal Seed Colour - Yellow vs Green Seed Shape - Round vs Wrinkled Pod Shape - Inflated vs Constricted Pod Colour - Green vs Yellow Stem Length - Tall vs Dwarf
What are hybrids?
The offspring of two different purebred varieties
How did Mendel determine the flower trait colour dominancy?
P Generation was with purebred white and purp
F1 generation was all power
F2 generation was 3:1 purple to white
What is the difference between phenotype and genotype?
Phenotype is what we see
Genotype is the actual allele distribution
What are Mendel’s 4 hypotheses?
- The alternative versions of genes are called alleles
- For each trait, an organism inherits two alleles, one from each parent. This organism is now diploid (remember gametes are haploid)
- If 2 alleles differ, only the dominant allele determines the phenotype
- 2 alleles in a diploid parent separate from each other so that their gametes only have one allele (haploid)
What is a Punnet Square?
A diagram used to predict outcomes of a cross breeding. It shows the combinations of gametes and the possible resulting offspring
What is complete dominance?
If this allele is present, it will display it’s phenotype over the recessive gene
How does genes relate to cystic fibrosis?
CF is a recessive genetic disorder. the C allele produces a normal function CFTR gene. A person with Cc is a carrier. A person with cc has CF, and both parents must have been carriers or have CF.
What is incomplete dominance?
Heterozygotes have an intermediate appearance between the two parents
An example would be snapdragon flower colour (RR = red, rr = white, Rr = pink)
What is co-dominance?
Both alleles are expressed in a heterozygous individual
An example would be blood cells (AA = A, BB = B, AB = AB)
If you receive incompatible blood, _____ occurs
clumping
For example, people of A has Anti B antibodies, meaning any B blood would clump (B/AB)
Describe the genetic makeup of bacteria vs eukaryotes
Bacteria: 1 circular chromosome, compact genome, no meiosis, exchange genetic material through conjugation, transformation, and transduction
eukaryotes: Often diploid, large genomes, meiosis, genes change though meiosis and fertilization
What are plasmids?
Small circular pieces of DNA
How do plasmids and bacteria relate?
Bacteria can have 1 or more plasmids that can insert themselves into the chromosome genome
Bacteria usually replicate via _______ ____________
asexual reproduction
What is binary fission?
When one bacteria divides into 2 identical daughters. Each daughter receives the exact same copy of circular chromosome and plasmids unless a mutation occurred
How can bacterial DNA change via external DNA?
Conjugation - Between a recipient and donor cell
Transformation - Update of naked DNA from the environment
Transduction - DNA transfer between bacteria using a viral vector
How does bacterial conjugation work?
The donor cell forms a pilus that connects to the recipient cell. Then a copy of part or all of the donor’s plasmid (and/or part of the chromosome) is transferred to the recipient
In bacterial transformation, where can the naked DNA go?
Inserted into the chromosome/plasmid, or it may create a new plasmid
What is antimicrobial resistance? Why is it bad?
When a bacteria, virus, fungi, or parasite change over time and no longer responds to medicines.
Increase likelihood of death and disability, prolonged illness, and longer hospital stays
Promotes the need for more expensive medicines and increases healthcare costs
How do bacteria develop AMR?
Artificial selection through mutation that provide antibiotic resistance for bacteria expose to antibiotics
Update of resistive genes from other bacteria or the environment (conjugation and transformation)
