Genetics Flashcards
What is the difference between human characteristics and human traits?
Characteristics are features such as eye or hair colour, well traits are variations of these characteristics, such as brown vs blue eyes
Are all traits visible, including example?
No, as some traits may be shown by the resistance against a certain bacteria, like how some Jack Pines resist drought better than others, and some Magpies can fly longer distances
Definition of heredity?
The transmission of characteristics from one generation to the next
What are heritable characteristics?
Characteristics that can be passed on from parent to offspring
Ex: Eye colour, hair type, skin colour
What are non-heritable characteristics?
Characteristics that cannot be passed on from parent to offspring
Ex: dyed hair colour, coloured contacts, ear piercings
What is a discrete variation, with example?
A discrete variation is a variation that is an either/or.
Ex: White or purple flowers on a specific plant, earlobes are attached or not
What is a continuous variation, with example?
A variation that comes in a range of forms, is not one or another
Ex: average height of adult human ranges from 1.2m to 2.1m
Can environmental factors affect variations of an organism, with example?
Yes. Sun exposure, soil acidity, and a number of other factors can affect the variations.
Ex: two identical plants, one in sunny window other in dim closet. One thrives, other dies
How does the science of DNA explain why some dogs are pure bred while other are varied?
When you breed two chihuahuas, the pups get a complete ‘blueprint’ for a chihuahua from the DNA, well mixed breeds have two different blueprints which result in more variance of the characteristics
What are genes, what do they contain, and what are they responsible for?
Genes are: uninterrupted segments of DNA
Which contain: instructions for specific characteristics
And they are responsible for: the inheritance of these characteristics
What are 3 facts about genes?
*Genes are located on chromosomes
*Each chromosome contains many genes
*Like chromosomes, genes come in pairs
*Gene pairs have matching positions on paired chromosomes
*Both genes in a pair have the DNA instructions for a characteristic
*The DNA in paired genes may not be identical, so it may produce different traits or variations of a characteristic
What is an allele?
An allele is the genetic code for a specific trait or variation of a characteristic
What is the key difference between a gene and an allele?
A gene contains the code for a specific characteristic, well an allele contains the code for a specific trait or variation of that characteristic. A gene pair may have the same genes but different alleles.
What is a punnet square?
A punnet square is a square that is divided into a grid in order to show the different combinations of genes and their results.
If dominant and recessive traits line up, do
Dominant will show over recessive.
Mom - recessive (tt)
trait 1 trait 2
———————
| | | Dad - dominant + recessive (Tt)
| Tt | Tt | Trait 1
———————
| | | trait 2
| tt | tt |
———————
50/50 chance of dominant or recessive
What color would the kittens of a pure bred black cat and pure bred white cat be, and why?
Black fur= dominant trait white fur= recessive trait
A pure bred black cat (BB) with a pure bred white cat (bb)
Will have only black kittens. This is because:
Black cat
__B____B__
Bb|Bb| b White cat
Bb|Bb| b
All have dominant trait, no chance of white
Can 2 black cats have a white kitten, and how?
Black fur= dominant white fur= recessive
In the case that both cats are black with recessive white gene (Bb), there is a 1 out of 4 or 25% chance of a white kitten. This is because:
Black cat with recessive
__B____b__
BB|Bb| B black cat with recessive
Bb|*bb| b
50% have black with recessive
25% have pure black
25% have pure white
What is a recessive vs. dominant gene?
Recessive genes- can be passed down, but don’t appear when paired with dominant gene. More rare variations.
Ex: white fur
Dominant genes- will show above recessive genes, more common variations.
Ex: Black fur
What are the chances of a black cat with recessive and pure bred white cat having a white kitten, and why?
Black fur= dominant White fur= recessive
There is a 1 out of 2 or 50% chance of a white kitten. This is because:
Black cat with recessive
__B____b__
Bb|bb| b White cat
Bb|bb| b
2 out of 4 possibilities result in white fur.
What is the real life application of the genetics section?
Mr. Koroluk having lost the battle of genetics twice, with 2 blonde kids.
Mr. Koroluk: mom is brown haired(dominamt gene), dad is blonde(recessive gene), Bb
His wife: both genes are blonde, bb
Punnet square:
Mr. Koroluk
B b
Bb|bb| b His wife
Bb|bb| b
50/50 chance of blonde or brown hair, both kids are blonde.
